Symmetricom GPS Receiver 58503B User Manual

097-58503-13

Issue 2: Jul 00

58503B

GPS Time and Frequency

Reference Receiver

and

59551A

GPS Measurements

Synchronization Module

Operating and Programming

Guide

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Contents

In This Guide

Front and Rear Panels at a Glance

58503B Front Panel at a Glance

58503B/Option 001 Front-Panel Display/Keypad at a

Glance

58503B Rear Panel at a Glance

59551A Front Panel at a Glance

59551A Rear Panel at a Glance

Serial Interface Capabilities

Chapter Contents

About the RS-232C Serial Port(s)

PORT 1 Rear-Panel RS-232C Serial Port

PORT 2 Front-Panel RS-232C Serial Port (59551A Only)

Connecting a Computer or Modem

To Connect the GPS Receiver to a PC or Modem Via the

Rear-Panel PORT 1

Connecting to the Personal Computer (PC)

Connecting to a Modem

Making Your Own Cables

Configuring the RS-232C Port(s)

Making Changes to the Serial Port Settings (If Needed) 10

Configuring PORT 1 of the 59551A 10

Configuring PORT 1 of the 58503B and PORT 2 of the

59551A 10

Determining the Serial Port Settings 11

Standard 58503B and 59551A 11

Visual User Interface

Chapter Contents

Using and Reading the Visual User Interface (the Receiver

Status Screen)

Tutorial on Using the Status Screen to Interface With the

Receiver

Demonstration of Holdover Operation

Receiver Status Screen Data 11

SYNCHRONIZATION Section of the Status Screen 12

SYNCHRONIZATION Summary Line 12

SmartClock Mode 12

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Contents

Reference Outputs 13

ACQUISITION Section of the Status Screen 14

ACQUISITION Line 14

Tracking, Not Tracking 14

Time 16

Position 17

HEALTH MONITOR Section of the Screen 18

The Receiver Status Screen at a Glance 20

Command Quick Reference

Chapter Contents

An Introduction to GPS Receiver Commands

SCPI Conformance Information

Command Syntax Conventions

Command Presentation

GPS Satellite Acquisition

1 PPS Reference Synchronization

Operating Status

System Time 10

Programmable Pulse Output (59551A Only) 11

Event Time Stamping (59551A Only) 12

Serial Interface Communication 13

Receiver Initialization 14

Receiver Identification/Upgrade 15

Receiver Commands at a Glance 17

Status Reporting System at a Glance 18

Command Reference

Chapter Contents

Command Syntax Conventions

Description Format

Commands and Returns

Query-Specific Information

Description of Response Formats (ASCII-encoded)

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Contents

GPS Satellite Acquisition

1 PPS Reference Synchronization 27

Operating Status 39

System Time 73

Programmable Pulse Output (59551A Only) 83

Event Time Stamping (59551A Only) 89

Serial Interface Communication 100

Receiver Initialization 109

Receiver Identification/Upgrade 113

Error Messages

Introduction

Reading an Error

Error Queue

Error Types

No Error

Syntactic Error

Semantic Error

Hardware/Firmware Error

Query Error

General Error Behavior

List of Errors

Command Syntax and Style

Appendix Contents

Command Types, Format, and Elements

Command Types

Command Formats

Common Command Format

SCPI Command and Query Format

Elements of SCPI Commands

Common Command Syntax

Subsystem Command Syntax

Abbreviated Commands

Keyword Separator

Parameter Data Types

Parameter Separator

Query Parameters

Suffixes

Suffix Elements

Suffix Multipliers

Command Terminator

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Contents

Using Multiple Commands

Program Messages

Program Message Syntax

Elements of Response Messages

Response Messages

Response Message Syntax

Response Formats 10

Reference Documentation 12

Receiver Firmware Installation

Downloading New Firmware Using SatStat Program

Performance Tests

Introduction

Operational Verification

Complete Performance Tests

Test Record

Equipment Required

Before You Start

Operational Verification

Introduction

Power-Up Procedure

10 MHz Verification (58503B Only)

1 PPS Verification

IRIG-B Verification (59551A Only)

Time of Day and PORT 1 RS-232C Serial Interface

Verification

Antenna Power Verification

Front Panel Display/Keypad Verification (58503B Option 001

Only) 10

Time Tagging (Stamping) Verification and Programmable

Verification (59551A Only) 11

Programmable Pulse Verification (59551A Only) 13

Operational Verification Conclusion 15

In Case of Difficulty 16

Complete Performance Tests 17

Preliminary Test Setup 18

Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter (Locked to

GPS) 19

Specifications Tested 19

Procedure 19

Test 2: 10 MHz Holdover Aging and 1 PPS Accumulated Time

Error (Unlocked) 22

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Contents

Specifications Tested 22

Procedure 22

Test 3: 1 PPS Time Accuracy (Locked) 24

Test 4: 10 MHz Frequency Stability (Time Domain) and Phase

Noise (Frequency Domain) Measurements 24

Frequency Stability (Time Domain) 24

Phase Noise (Frequency Domain) 24

58503B Performance Test Record 26

59551A Performance Test Record

58503B Specifications

Specifications and Characteristics

GPS Receiver Features

Other Information

Options and Accessories

59551A Specifications

Specifications and Characteristics

GPS Receiver Features

Other Information

Options and Accessories

Command Index

General Index

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Contents

viii

Operating and Programming Guide

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In This Guide

Chapter 1, “Front and Rear Panels at a Glance,” provides overview

of the Receiver’s indicators, inputs, and outputs.

Chapter 2, “Serial Interface Capabilities,” provides RS-232 serial

interface port connection and configuration instructions.

Chapter 3, “Visual User Interface,” which is subtitled “Using the

Receiver Status Screen,” provides information on how to use the

Receiver Status screen and the SatStat program. An illustrated foldout

of the Receiver Status screen, which is a comprehensive summary of

key operation conditions and settings, is provided at the end of this

chapter.

Chapter 4,“Command Quick Reference,” is a quick reference that

summarizes the Receiver commands. The commands are presented or

grouped by their functions. A foldout sheet that presents all of the

commands on one side (Receiver Commands at a Glance) and

illustrates the status reporting system on the other side (Status

Reporting System at a Glance) is provided at the end of this chapter.

Chapter 5, “Command Reference,” provides a description of each

command that can be used to operate the GPS Receiver.

The commands are grouped by functions. The functions are grouped

and ordered the same as they are in Chapter 4, “Command Quick

Reference,” and on the foldout “Receiver Commands at a Glance

(cont’d).” A comprehensive discussion on how you can monitor and

control alarm conditions using the status registers is also provided in

this chapter.

Appendix A, “Error Messages,” lists all error messages the Receiver

could generate along with descriptions of possible causes for the errors.

Appendix B, “Command Syntax and Style,” provides an overview of

the Standard Commands for Programming Instrument (SCPI) syntax

and style to help you program the Receiver.

Appendix C, “Receiver Firmware Installation,” provides a

procedure for downloading new firmware to the GPS Receiver.

Appendix D, “Performance Tests,” provides procedures that verify

the GPS Receivers operate properly and meet electrical performance

specifications. Electrical performance is tested against the

specifications listed in Appendix E, “58503B Specifications,” and

Appendix F, “59551A Specifications,” in this guide.

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In This Guide

Appendix E, “58503B Specifications,” lists the product specifications

and characteristics.

Appendix F, “59551A Specifications,” lists the product specifications

and characteristics.

Command Index, lists all of the commands alphabetically and

provides page references.

General Index

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Front and Rear Panels at a Glance

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Chapter 1 Front and Rear Panels at a Glance

58503B Front Panel at a Glance

1 When the Power indicator

illuminates, it indicates that the

proper input power is supplied to the

Receiver.

3 When the Holdover indicator

illuminates, it indicates that the

Receiver is NOT locked to the GPS

signal. The Receiver is keeping time

based on the internal reference

oscillator signal. The internal

reference oscillator will determine

the accuracy of the 1 PPS signal and

the 10 MHz reference output.

2 When the GPS Lock indicator

illuminates, it indicates that the

Receiver is receiving the GPS signal

and is locked on one or more

satellite(s).

4 When the Alarm indicator

illuminates, it indicates that the

Receiver has detected an internal

condition that requires attention.

1-2

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Chapter 1 Front and Rear Panels at a Glance

58503B/Option 001 Front-Panel Display/Keypad at a Glance

58503B/Option 001 Front-Panel

Display/Keypad at a Glance

An alphanumeric display for displaying time, position (i.e., longitude,

latitude, and altitude), and Receiver status. The display is a highly visible

twelve-character vacuum-fluorescent display.

Status LED indicators:

When the Power indicator is illuminated, it indicates that input power is

supplied to the Receiver.

When the GPS Lock indicator is illuminated, it indicates that the

Receiver is tracking satellites and has phase-locked its internal reference

to the reference provided by GPS.

When the Holdover indicator is illuminated, it indicates that the Receiver

is not phase-locking its internal reference to the reference provided by

GPS. Typically, this would happen due to loss of satellite tracking.

When the Alarm indicator is illuminated, it indicates that the Module has

detected a condition that requires attention.

Eight MODE keys with associated LEDs for front-panel access to time,

position, and status information: Time, Long (longitude), Lat (latitude)

Alt (altitude), Sat (number of satellites tracking), Status (Receiver or

system status), and Serial Port (serial port settings). Each key selects a

different display mode. Also, pressing Shift and Alt key in sequence clears

instrument alarm.

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Chapter 1 Front and Rear Panels at a Glance

58503B Rear Panel at a Glance

1 ANT N-type (female) connector for

Option 002 1 PP2S

GPS Antenna connection.

(One-Pulse-Per-Two-Seconds)

connector for outputting a pulse

every other second, synchronized to

the even seconds in GPS time.

Pulses occur on even-numbered

seconds (i.e., 2 seconds, 4 seconds,

etc.).

2 PORT 1 RS-232C, DB-25 (female)

serial interface port for remote

control, monitoring, and

downloading of the Receiver’s

memory data and upgrading

Receiver software.

6 Alarm output for external devices

(such as red light, bell, or horn) to

indicate that the Receiver has

detected an internal condition that

requires attention.

3 10 MHz OUT output for user-specific

applications.

4 1 PPS connector for outputting a

continuous 1 Pulse Per Second

signal.

7 POWER input jack.

1-4

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Chapter 1 Front and Rear Panels at a Glance

59551A Front Panel at a Glance

1 When the Power indicator

illuminates, it indicates that the

proper input power is supplied to

the Module.

4 When the Alarm indicator

illuminates, it indicates that the

Module has detected an internal

condition that requires attention.

2 When the GPS Lock indicator

illuminates, it indicates that the

Module is receiving the GPS signal

and is locked on one or more

satellite(s).

5 PORT 2 RS-232C, DE-9S (female)

serial interface port for local

monitoring and retrieving data

stored in the Module’s memory

data.

3 When the Holdover indicator

illuminates, it indicates that the

Module is NOT locked to the GPS

signal. The Module is keeping time

based on the internal reference

oscillator signal. The internal

reference oscillator will determine

the accuracy of the 1 PPS signal.

(See specification for Accuracy in

Holdover in Appendix F, “59551A

Specifications,” in this guide.)

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Chapter 1 Front and Rear Panels at a Glance

59551A Rear Panel at a Glance

1 1 PPS (One-Pulse-Per-Second)

connector for outputting a

continuous one pulse per second

signal.

5 Alarm BITE (Built-In Test

Equipment) output for external

devices (such as red light, bell, or

horn) to indicate that the Module

has detected an internal condition

that requires attention. The relay

opens and closes with the Alarm

indicator. (Mating connector is

Amphenol part number 31-224

[glass-filled Noryl] or #31-2226

[Telfon]).

2 Programmable Pulse output connector

for outputting pulses at user-specified

time/period.

3 IRIG-B output for outputting

formatted time-code signals. (This

signal is used for general purpose

time distribution and magnetic

tape annotation applications

requiring the time of year.)

6 ANTENNA N-type (female)

connector for GPS antenna

connection.

4 Time tag input connectors for

receiving TTL conditioned time

tagging signals.

7 PORT 1 RS-232C, DB-25 (female)

serial interface port for remote

control, monitoring, and retrieving

of the Module’s memory data and

upgrading Module software.

8 AC POWER input jack. The AC

input jack is standard. The unit

operates from ac voltage. It can also

be operated from dc voltage via this

ac jack by using the supplied IEC

320 dc connector plug.

1-6

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Serial Interface Capabilities

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Chapter 2 Serial Interface Capabilities

Chapter Contents

This chapter describes how to operate the 59551A GPS Measurements

Synchronization Module and the 58503B GPS Time and Frequency

Reference Receiver via the RS-232C serial interface port. Hardware

connections and configuration are discussed.

This chapter is organized as follows:

• About the RS-232C Serial Port(s)

page 2-3

page 2-4

–

PORT 1 Rear-Panel RS-232C Serial Port

PORT 2 Front-Panel RS-232C Serial Port

(59551A Only)

• Connecting a Computer or Modem

page 2-5

–

To Connect the GPS Receiver to a PC or Modem Via page 2-6

the Rear-Panel PORT 1

–

To Connect the GPS Receiver to a PC or Modem Via page 2-6

the Rear-Panel PORT 1

• Configuring the RS-232C Port(s)

page 2-9

–

Making Changes to the Serial Port Settings

(If Needed)

page 2-10

–

Determining the Serial Port Settings

page 2-11

2-2

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Chapter 2 Serial Interface Capabilities

About the RS-232C Serial Port(s)

The 58503B has only a rear-panel (PORT 1) RS-232C serial interface

port.

The 59551A has separate rear-panel (PORT 1) and front-panel

(PORT 2) RS-232C serial interface ports.

The rear-panel (PORT 1) RS-232C serial interface port is the only port

which can be used to upgrade the Receiver firmware; therefore, it is

referred to as the PRIMARY port. The 59551A’s front-panel (PORT 2)

RS-232C serial interface port is referred to as the SECONDARY port

because it cannot be used to upgrade the Receiver firmware. The

operation and configuration of these ports are described in the

following paragraphs. More information is provided in the sections

titled “Connecting a Computer or Modem” and “Configuring the

RS-232C Port(s)” in this chapter on page 2-5 and page 2-9,

respectively.

Either port allows you full communication with the Receiver. This can

be done by connecting any computer with an RS-232C serial interface

and suitable terminal emulation software, then sending the correct

commands for transmitting or retrieving data.

PORT 1 Rear-Panel RS-232C Serial Port

This 25-pin female subminiature D (DB-25) connector (PORT 1)

RS-232C Serial Interface Port is located on the rear panel.

The pins used for PORT 1 RS-232C communication are described in

Table 2-1.

NOTE

We reserve the right to impose signals on other pins; therefore, your

connection should be restricted to the pins described in Table 2-1.

Table 2-1. PORT 1 Rear-Panel RS-232C Serial Port Connections

*Pin

Input/Output

Description

Number

Output

Transmit Data (TxD). GPS Receiver output.

Receive Data (RxD). GPS Receiver input.

Signal Ground (SG)

Input

_____

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Chapter 2 Serial Interface Capabilities

About the RS-232C Serial Port(s)

Refer to the sections titled “Connecting a Computer or Modem” in this

chapter, on page 2-5, for wiring diagrams and more information on the

RS-232C interface cables.

PORT 2 Front-Panel RS-232C Serial Port

(59551A Only)

This 9-pin female subminiature D (DB-9) connector (PORT 2) RS-232C

Serial Interface Port is located on the front panel.

The pins used for PORT 2 RS-232C communication are described in

Table 2-2.

NOTE

We reserves the right to impose signals on other pins; therefore, your

connection should be restricted to the pins described in Table 2-2.

Table 2-2. PORT 2 Front-Panel RS-232C Serial Port Connections

(59551A Only)

*Pin

Input/Output

Description

Number

Input

Receive Data (RxD). GPS Receiver input.

Transmit Data (TxD). GPS Receiver output.

Signal Ground (SG)

Output

_____

Refer to the sections titled “Connecting a Computer or Modem” in this

chapter, on page 2-5, for wiring diagrams and more information on the

RS-232C interface cables.

2-4

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Chapter 2 Serial Interface Capabilities

Connecting a Computer or Modem

To connect the GPS Receiver to a computer or modem, you must have

the proper interface cable. Most computers are DTE (Data Terminal

Equipment) devices. Since the Receiver is also a DTE device, you must

use a DTE-to-DTE interface cable when connecting to a computer.

These cables are also called “null-modem”, “modem-eliminator”, or

“crossover” cables.

Most modems are DCE (Digital Communication Equipment) devices;

thus, you must use a DTE-to-DCE interface cable.

The interface cable must also have the proper connector on each end

and the internal wiring must be correct. Connectors typically have

9 pins (DE-9 connector) or 25 pins (DB-25 connector) with a “male” or

“female” pin configuration. A male connector has pins inside the

connector shell and a female connector has holes inside the connector

shell.

To simplify interface cable selections, the following sections

tells you which cables to use.

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Chapter 2 Serial Interface Capabilities

Connecting a Computer or Modem

To Connect the GPS Receiver to a PC or Modem Via

the Rear-Panel PORT 1

Connecting to the Personal Computer (PC)

Use an HP 24542G interface cable or equivalent to connect the

Receiver’s rear-panel PORT 1 DB-25 female connector to a PC as

shown in Figure 2-1. See “Making Your Own Cables” starting on

page 2-8.

GPS Receiver

(Rear view)

Computer

WARNING: ^{NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO SERVICE TRAINED PERSONNEL.}

OUTPUTS

pps Programmable Irig-B

TOD

INPUTS

ALARM BITE

ANTENNA

Time Tag Time Tag Time Tag

POWER

129 VDC

48 VDC

FOR LABORATORY USE BY

QUALIFIED PERSONNEL

FOUR USAGE EN LABORATOIRE

PAR PERSONNEL QUALIFIE

Port

129 VDC

SERIAL PLATE

WARNING: ^{FOR CONTINUED FIRE PROTECTION, USE SPECIFIED}

LINE FUSE.

HP 24542G

or equivalent

Figure 2-1. Connecting the GPS Receiver to a PC or Laptop

Connecting to a Modem

Use an HP 40242M interface cable or equivalent to connect the

Receiver’s rear-panel PORT 1 DB-25 female connector to a modem,

which is a DCE (Digital Communication Equipment) device, as shown

in Figure 2-2. See “Making Your Own Cables” starting on page 2-8.

2-6

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Chapter 2 Serial Interface Capabilities

Connecting a Computer or Modem

GPS Receiver

(Rear view)

WARNING: ^{NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO SERVICE TRAINED PERSONNEL.}

OUTPUTS

pps Programmable Irig-B

TOD

INPUTS

ALARM BITE

ANTENNA

Time Tag Time Tag Time Tag

POWER

129 VDC

48 VDC

FOR LABORATORY USE BY

QUALIFIED PERSONNEL

FOUR USAGE EN LABORATOIRE

PAR PERSONNEL QUALIFIE

Port

129 VDC

SERIAL PLATE

WARNING: ^{FOR CONTINUED FIRE PROTECTION, USE SPECIFIED}

LINE FUSE.

Modem set to

Auto-Answer

Telephone

Line

HP 40242M

or equivalent

Figure 2-2 Connecting the GPS Receiver to a Modem

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Chapter 2 Serial Interface Capabilities

Connecting a Computer or Modem

Making Your Own Cables

If you choose to make your own cable, see Figure Figure 2-3 and

Figure Figure 2-4.

Figure Figure 2-3 illustrates how to make a DE-9S-to-DE-9P, DTE-

to-DCE interface cable that can replace the cable and adapter

combination of the HP 24542U cable and the HP 5181-6639 adapter for

use with PORT 2 of the 59551A.

Data

Terminal

Data

Communications

Equipment

59551A PORT 2

RS-232C (9-pin)

DE-9S-to-DE-9P

(DTE-to-DCE) Interface Cable

RS-232C (9-pin)

Instrument input

Instrument output

PC input

PC output

GND

DE-9P

Male

DE-9S

Female

DE-9P DE-9S

Male Female

Figure 2-3 DE-9S-to-DE-9P (DTE-to-DCE) Serial Interface Connection

to PORT 2

Figure Figure 2-4 illustrates how to make a DE-9S-to-DB-25P,

DTE-to-DTE interface cable that can replace the HP 24542G cable

(25-pin male to 9-pin female connectors) for use with PORT 1.

Data

Terminal

Data

DE-9S-to-DB-25P

(DTE-to-DTE)

Interface cable

Terminal

Equipment

PORT 1

RS-232C (25-pin)

RS-232C (9-pin)

Instrument output

Instrument input

PC input

PC output

GND

DE-9P DE-9S

Male Female

DB-25P

Male

DB-25S

Female

Figure 2-4 DE-9S-to-DB-25P (DTE-to-DTE) Serial Interface

Connection to PORT 1

2-8

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Chapter 2 Serial Interface Capabilities

Configuring the RS-232C Port(s)

The 59551A has separate rear-panel (PORT 1) and front-panel

(PORT 2) RS-232C serial interface ports.

The 58503B has one RS-232C serial interface port (PORT 1) on the

rear panel. Note: PORT 1 of the 58503B and PORT 2 of the 59551A

have the same configuration capabilities as indicated in Table 2-4.

Software pacing, baud rate, parity, data bits, and stop bits parameters

for each port are user-selectable and independent of the configuration

of the other.

Table 2-3 and Table 2-4 list the configuration factory-default values for

PORT 1 and PORT 2.

Table 2-3. Factory-Default Values for PORT 1 of the 59551A

Parameter

Default

Possible Choices

XON or NONE

1200, 2400, 9600, or 19200

EVEN, ODD, or NONE

7 or 8

Software Pacing NONE

Baud Rate

Parity

9600

NONE

Data Bits

Stop Bits

Full Duplex

1 or 2

ON or OFF

Table 2-4. Factory-Default Values for PORT 1 or the 58503B and

PORT 2 of the 59551A

Parameter

Default

Possible Choices

Software Pacing NONE

XON or NONE

Baud Rate

Parity

9600

NONE

1200, 2400, 9600, or 19200

EVEN, ODD, or NONE

Data Bits

Fixed at 7 when parity is even or odd.

Fixed at 8 when parity is none.

Stop Bits

Fixed (no choices available)

ON or OFF

Full Duplex

Procedures for configuring the RS-232C ports are provided in the

following paragraphs.

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Chapter 2 Serial Interface Capabilities

Configuring the RS-232C Port(s)

Making Changes to the Serial Port Settings

(If Needed)

CAUTION

If you change the serial port settings, your changes will be

stored in the Receiver. Cycling power will not reset to factory

defaults. Therefore, if you make a change, it is recommended

that you record the settings and keep the record with the

Receiver.

If you need to change the serial port settings, for example, to set

up for a different computer, use the guidelines given in this

section.

Serial port settings are changed by issuing commands.

It is recommended that you issue a single compound command which

simultaneously sets all the serial port parameters. Then connect the

other computer and begin using the instrument with the new settings.

NOTE

If you choose to set parameters one at a time, you will make the

procedure more difficult. That is, with each change, the instrument

will be updated, but your computer will retain its original settings.

At each step, you will have stopped serial communications and be

forced to modify your PC settings to match the Receiver in order to

continue. It is recommended that you make all changes in a single

compound command, verify the changes, and record all parameters.

Configuring PORT 1 of the 59551A

Complete configuration of PORT 1 of the 59551A requires that you set

five parameters. The command line sent in the following example

would set the RS-232C port pacing to XON, baud rate to 2400, parity to

EVEN, data bits to 7, and stop bits to 2. This command line must be

transmitted on PORT 1.

SYST:COMM:SER:PACE XON; BAUD 2400; PARITY EVEN; BITS 7; SBITS 2

Configuring PORT 1 of the 58503B and PORT 2 of the

59551A

Complete configuration of PORT 1 (58503B) and PORT 2 (59551A)

require that you set three parameters. The command line sent in the

following example would set the RS-232C port pacing to XON, baud

rate to 2400, and parity to EVEN. This command line must be

transmitted on PORT 1 or PORT 2.

SYST:COMM:SER2:PACE XON; BAUD 2400; PARITY EVEN

2-10

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Chapter 2 Serial Interface Capabilities

Configuring the RS-232C Port(s)

Determining the Serial Port Settings

Standard 58503B and 59551A

If you connect your PC, press Return, and do not get a scpi> prompt

back from the Receiver, your Receiver’s serial communication settings

may have been modified. You need to systematically step through the

data communication settings on your PC until your PC matches the

Receiver. The Receiver cannot communicate its settings until this

process is complete.

Iterate until you are able to verify that settings on your PC match the

Receiver.

When you are successful, you will have restored full RS-232C

communications, enabling you to query the Receiver’s communication

settings. Once you establish communications with one serial port, you

can query the Receiver for settings of either port.

Issue the following queries to either serial port to verify PORT 1’s

configuration.

SYST:COMM:SER:PACE?

SYST:COMM:SER:BAUD?

SYST:COMM:SER:PARITY?

SYST:COMM:SER:BITS?

SYST:COMM:SER:SBITS?

Issue the following queries to either serial port to verify PORT 2’s

configuration.

SYST:COMM:SER2:PACE?

SYST:COMM:SER2:BAUD?

SYST:COMM:SER2:PARITY?

SYST:COMM:SER2:BITS?

SYST:COMM:SER2:SBITS?

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Configuring the RS-232C Port(s)

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Visual User Interface

Using the Receiver Status Screen

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Chapter 3 Visual User Interface

Chapter Contents

This chapter provides a tutorial section on how to use the Receiver

Status Screen, a comprehensive reference information section, and an

illustrated foldout of the Receiver Status Screen, which is a

comprehensive summary of key operation conditions and settings.

This chapter is organized as follows:

• Using and Reading the Visual User Interface (the

Receiver Status Screen)

page 3-3

– Tutorial on Using the Status Screen to Interface With

the Receiver

page 3-3

– Demonstration of Holdover Operation

• Receiver Status Screen Data

page 3-8

page 3-11

page 3-12

page 3-14

page 3-18

page 3-20

– SYNCHRONIZATION Section of the Status Screen

– ACQUISITION Section of the Status Screen

– HEALTH MONITOR Section of the Screen

• The Receiver Status Screen at a Glance (foldout)

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

Using and Reading the Visual User

Interface (the Receiver Status Screen)

The combination of the PC and the GPS Receiver yields a visual user

interface called the Receiver Status Screen that lets you see what the

Receiver is doing and how it is progressing towards tracking satellites

to eventually lock to the GPS signal.

When connected to a properly configured PC, the Receiver Status

Screen can be accessed. There are two ways to access and use the

Receiver Status Screen:

• By installing a commercially available terminal emulation

program, connecting the Receiver to a PC via the PORT 1 port, and

manually sending the :SYSTEM:STATUS? query. (Refer to Chapter 1,

“Getting Started,” in 58503B/59551A Getting Started Guide.)

• By installing and operating the SatStat program, which

automatically generates continual status screen updates, and

connecting the Receiver to a PC via PORT 1. (Refer to the sections

titled “Installing the Automated SatStat Program for Continual

Status Updates” and “Operating the Automated SatStat Program”

in Chapter 1, “Getting Started,” of the 58503B/59551A Getting

Started Guide for details on installation and operation.)

The following tutorial demonstrates how you can use the Receiver

Status Screen to observe Receiver operation. The tutorial uses the

manual (:SYSTEM:STATUS?) method.

Tutorial on Using the Status Screen to Interface With

the Receiver

Type :SYSTEM:STATUS? at the scpi> prompt.

An initial power-up screen is displayed, which is similar to the

demonstration screen shown in Figure 3-1. The first data that you

should look at is in the SYNCHRONIZATION area of the screen. It is

telling you that it is in the Power-up state as indicated by the >>

marker. That is, the Receiver has just been put on line.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

Receiver Status

----------------------------

SYNCHRONIZATION.........................................

[

Outputs Invalid

Reference Outputs

TFOM

]

SmartClock Mode

Locked

Recovery

FFOM

1PPS TI --

Holdover

Power-up:GPS acquisition

HOLD THR 1.000 us

Holdover Uncertainty

Predict --

.............................................[GPS 1PPS Invalid]

Not Tracking: 6

ACQUISITION

Tracking: 0

Time

UTC

PRN El Az

*1 -- ---

*6 -- ---

*9 -- ---

*14 -- ---

*22 -- ---

*24 -- ---

12:00:00[?]01 Jan 1996

GPS 1PPS Invalid: not tracking

ANT DLY 0 ns

Position

MODE

Survey: 0% complete

Suspended:track <4 sats

INIT LAT N 0:00:00.000

INIT LON W 0:00:00.000

INIT HGT

0 m (GPS)

[ OK ]

ELEV MASK 10 deg

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

*attempting to track

......................................................

OCXO: OK EFC: OK GPS Rcv: OK

Figure 3-1. Receiver Status Screen at Powerup

The ACQUISITION area of the screen is telling you that no satellites

have been tracked. The identification numbers of several satellites

appear in the Not Tracking column. The asterisk next to the satellite

identification number, or pseudorandom noise code (PRN), indicates

the Receiver is attempting to track it.

The current time and date are shown in the Time quadrant of the

ACQUISITION area. The default power-up setting, indicated by [?], is

corrected when the first satellite is tracked. Since the Receiver is not

tracking any satellites, the GPS 1 PPS reference signal is invalid.

An accurate position is necessary to derive precise time from GPS. The

Position quadrant indicates that the Receiver is in survey mode, which

uses GPS to determine the position of the GPS antenna. This process

has not yet started, since position calculations can be performed only

while tracking four or more satellites. INIT LAT, INIT LON, and INIT

HGT are the initial estimate of the true position. These coordinates are

refined by the survey process. The Receiver uses this position and the

time-of-day to select satellites to track. Therefore, you can reduce

satellite acquisition time by specifying a close approximation of

position and time.

Now, let’s send the :SYSTEM:STATUS? query again to see what kind of

progress the Receiver has made.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

You can now see that the Receiver is tracking several satellites as

shown in Figure 3-2. The process of acquiring and tracking satellites is

described in the following paragraphs.

Receiver Status

----------------------------

Outputs Valid/Reduced Accuracy

Reference Outputs

TFOM

SYNCHRONIZATION...........................

SmartClock Mode

>>Locked to GPS: stabilizing frequency

[

]

FFOM

Recovery

Holdover

Power-up

1PPS TI +71 ns relative to GPS

HOLD THR 1.000 us

Holdover Uncertainty

Predict --

...............................................[GPS 1PPS Valid]

Not Tracking: 4

ACQUISITION

Tracking: 5

Time

UTC

PRN El Az C/N PRN El Az

2 70 337 49

7 46 188 48 16 24 243

15 33 82 38 *26 Acq..

19 28 113 36 31 -- ---

22 65 91 49

17:56:44 31 Jan 1996

GPS 1PPS Synchronized to UTC

9 11 292

ANT DLY 0 ns

Position

MODE

Survey: 1.2%

complete

AVG LAT N 37:19:34.746

AVG LON W 121:59:50.502

AVG HGT

+34.14 m (GPS)

[ OK ]

OCXO: OK EFC: OK GPS Rcv: OK

*attempting to track

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

ELEV MASK 10 deg

......................................................

Figure 3-2. Receiver Status Screen Displaying Initial Satellite

Acquisition

An asterisk (*) next to the PRN of a satellite in the Not Tracking

column indicates the Receiver is attempting to track it. The elevation

(El) and azimuth (Az) angles of the satellite are indicated. Acq . or

Acq .. tell you that the Receiver is attempting to track that satellite.

One dot after the Acq indicator shows that the Receiver is attempting

to acquire its signal, and two dots indicate impending lock. Eventually,

you will see the satellite move to the Tracking column, which shows

the satellite PRN, the elevation angle of the satellite in the sky (90°

being zenith), the azimuth angle (number of degrees bearing from true

north), and the carrier-to-noise ratio (C/N). A good carrier-to-noise

ratio is a number above 35, which would be efficient for the Receiver to

operate. Numbers below 35, suggest intermittent tracking of the

satellite or no tracking; check your antenna system should this be the

case.

As indicated by the demonstration screen in Figure 3-2, the Receiver is

now surveying for position. It is tracking four satellites which is the

minimum number that must be tracked to determine postion. As you

can see, the Position MODE line indicates survey is 1.2% complete. A

complete survey would take two hours during which four satellites or

more are continuously tracked.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

Also, you can see the initial (estimated) position has been replaced

with a computed position, which the Receiver continuous to refine until

it gets a very accurate position. The status screen indicates that a

computed position is being used by displaying the averaged latitude,

and longitude height (AVG LAT, AVG LON, and AVG HGT).

If the position were not precise, GPS timing information would be

inaccurate by an amount corresponding to the error in the computed

position. An error in the computed position of the antenna translates

into an error in the derived time and will compromise the Receiver’s

ability to be a timing source.

Let’s consider a case where four satellites are not visible at powerup

because of a poor antenna location, such as an “urban canyon” (located

between tall city buildings). If accurate position is known from a

Geodetic survey of that site, it can be programmed with the position

command, thereby bypassing the survey operation. This is useful when

four satellites cannot be tracked for an extended period of time.

Let’s send the :SYSTEM:STATUS? query again to observe the current

status of the Receiver.

The updated demonstration status screen in Figure 3-3 indicates that

the position survey is now 5.4% complete. Thus, the survey task is

beginning to iterate toward an accurate position. In the Time

quadrant, the UTC time is now correct. The date is correct, and the

GPS reference signal is synchronized to UTC.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

Receiver Status

----------------------------

Outputs Valid/Reduced Accuracy

Reference Outputs

TFOM

SYNCHRONIZATION............................

SmartClock Mode

>>Locked to GPS: stabilizing frequency

[

]

FFOM

Recovery

Holdover

Power-up

1PPS TI +20 ns relative to GPS

HOLD THR 1.000 us

Holdrover Uncertainty

Predict 432.0 us/initial 24 hrs

...............................................[GPS 1PPS Valid]

Not Tracking: 1

ACQUISITION

Tracking: 6

PRN El Az C/N PRN El Az

2 70 301 40 16 13 258

7 35 186 38

19 40 102 38

22 71 60 39

26 19 317 36

31 16 41 35

Time

UTC

18:47:07 31 Jan 1996

GPS 1PPS Synchronized to UTC

ANT DLY 0 ns

Position

MODE

Survey: 5.4%

complete

AVG LAT N 37:19:34.937

AVG LON W 121:59:50.457

AVG HGT

+67.94 m (GPS)

[ OK ]

OCXO: OK EFC: OK GPS Rcv: OK

ELEV MASK 10 deg

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

......................................................

Figure 3-3. Receiver Status Screen Displaying Progress Towards

Steady-State Operation

In the SYNCHRONIZATION area, the >> marker is pointed at the

Locked to GPS line, indicating that the Receiver is locked to GPS and

stabilizing the frequency of its oscillator. This means that the Receiver

has phase-locked its oscillator to the 1 PPS reference signal provided

by GPS, but it is not at its final, or most stable, state. The Receiver is

locked and the front-panel GPS Lock LED is illuminated.

For users without the command interface (PC/Terminal emulator

connected to the Receiver), the illuminated GPS Lock LED is probably

the first indication that after powerup that the Receiver is moving

towards a stable state.

With the command interface and status screen, you can get more

detailed information. For example, you can read the reference outputs

quality indicators in the Reference Outputs area of the status screen.

These are the Time Figure of Merit (TFOM) and Frequency Figure of

Merit (FFOM) indicators. As shown in Figure 3-3, the TFOM is 4 and

the FFOM is 1. These values will eventually decrease towards the

ultimate values that represent steady-state performance. Refer to the

subsection titled ““Reference Outputs” on page 3-13 in this chapter for

more information about TFOM and FFOM.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

Also indicated is a prediction of the accuracy of the Receiver should it

go into holdover operation.

Demonstration of Holdover Operation

CAUTION

The Receiver typically reaches stable state 24 to 72 hours after

powerup, and it will learn best if its experiences no holdover in the first

24 hours. Therefore, the holdover demonstration in the following

paragraphs will compromise the Receiver’s ability to learn the

characteristics of its internal reference oscillator. For the purpose of

education only, you will be shown how to initiate a holdover.

A user should never initiate holdover during the first 24 hours while

the Receiver is learning its internal oscillator characteristics. The

Receiver should maintain GPS lock during this time because it is using

the GPS signal to discipline the oscillator. It will learn what the

oscillator drift characteristics are relative to the GPS signal. It will

learn how the oscillator ages, and the software will learn how to

compensate for that aging.

Thus, it is recommended that the Receiver is always kept locked to

GPS during the first 24 hours.

For demonstration purposes, and since the Receiver has been powered

up for a while, let’s put the Receiver into holdover by simply removing

the antenna connection. (Note that holdover also can be manually

initiated by sending the SYNCHRONIZATION:HOLDOVER:INITIATE

command; however, for this demonstration, disconnect the antenna

cable.) The following will occur after a verification delay:

• The front-panel Holdover LED will illuminate, and

• after sending the :SYSTEM:STATUS? query again, a screen similar to

Figure 3-4 should appear.

Let’s send the :SYSTEM:STATUS? query. Figure 3-4 should appear.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

Receiver Status

----------------------------

SYNCHRONIZATION...........................

----------------------------

[

Outputs Valid/Reduced Accuracy

Reference Outputs

TFOM

]

SmartClock Mode

Locked to GPS

Recovery

FFOM

1PPS TI --

HOLD THR 1.000 us

Holdover Uncertainty

>>Holdover: GPS 1PPS invalid

Power-up

Predict 432.0 us/initial 24 hrs

Holdover Duration: 0m 14s Present 1.0 us

.............................................[GPS 1PPS Invalid]

Not Tracking: 7

ACQUISITION

Tracking: 0

Time

UTC

PRN El Az PRN El Az

*2 71 316 *31 12 29

*7 41 186

20:56:14 31 Jan 1996

GPS 1PPS Inaccurate: not tracking

ANT DLY 0 ns

Position

15 11 86

*19 35 107

*22 68 78

*26 23 314

MODE

Survey: 71.1% complete

LAT

LON

HGT

N 37:19:32.472

W 121:59:51.784

+42.19 m (GPS)

ELEV MASK 10 deg *attempting to track

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

[ OK ]

......................................................

OCXO: OK EFC: OK GPS Rcv: OK

Figure 3-4. Receiver Status Screen Displaying Holdover Operation

In the SYNCHRONIZATION area, you can see that the Receiver has

gone into holdover as indicated by >> marker that is pointing at the

Holdover line. The status screen indicates that the reason the Receiver

is in holdover is because the GPS 1 PPS reference signal is invalid.

You would expect this since the antenna has been disconnected.

The status screen shows loss of the GPS signal. As you can see on the

screen, all of the satellites in the Tracking column moved into the Not

Tracking column.

The status screen in Figure 3-4 shows that the Receiver has been in

holdover operation for 14 seconds.

If the Receiver SmartClock had had enough time to learn the internal

oscillator characteristics, the Receiver Status Screen would show that

the Receiver went into holdover, and the Receiver’s outputs were

maintained during holdover by the SmartClock.

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Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

When the GPS antenna is re-connected and the GPS signal has been

re-acquired, the Receiver has the ability to recover from holdover by

itself. The SYNCHRONIZATION area of the screen will show the >>

marker pointing at the Recovery line (and then eventually at the

Locked to GPS line), the GPS Lock LED will illuminate, and the screen

will look similar toFigure 3-5.

Receiver Status

----------------------------

Outputs Valid/Reduced Accuracy

Reference Outputs

TFOM

SYNCHRONIZATION............................

SmartClock Mode

>>Locked to GPS: Stabilizing frequency

[

]

FFOM

Recovery

Holdover

Power-up

1PPS TI +10.6 ns relative to GPS

HOLD THR 1.000 us

Holdover Uncertainty

Predict 432.0 us/initial 24 hrs

...............................................[GPS 1PPS Valid]

Not Tracking: 0

ACQUISITION

Tracking: 6

PRN El Az C/N

2 71 317 40

7 34 185 38

19 41 101 37

22 67 80 40

26 24 312 37

31 12 27 36

Time

UTC

20:59:28 31 Jan 1996

GPS 1PPS Synchronized to UTC

ANT DLY 0 ns

Position

MODE

Survey: 71.4% complete

LAT

LON

HGT

N 37:19:32.486

W 121:59:52.082

+40.06 m (GPS)

ELEV MASK 10 deg

[ OK ]

......................................................

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

OCXO: OK EFC: OK GPS Rcv: OK

Figure 3-5. Receiver Status Screen Following Recovery from

Holdover Operation

You can see the Receiver has recovered from holdover almost

immediately and it has returned to locked operation.

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Chapter 3 Visual User Interface

Receiver Status Screen Data

This section defines the data displayed in the Receiver Status Screen,

shown in Figure 3-6.

Receiver Status

----------------------------

Outputs Valid

SYNCHRONIZATION..........................................

[

Reference Outputs

]

SmartClock Mode

Locked to GPS

TFOM

FFOM

Recovery

Holdover

Power-up

1PPS TI +7.2 ns relative to GPS

HOLD THR 1.000 us

Holdover Uncertainty

Predict 49.0 us/initial 24 hrs

................................................[GPS 1PPS Valid]

Not Tracking: 1

ACQUISITION

Tracking: 6

PRN El Az C/N PRN El Az

Time

UTC

+1 leap second pending

23:59:59 31 Dec 1995

2 49 243 49

16 24 282 46

18 38 154 47

19 65 52 49

27 62 327 49

31 34 61 47

14 11 82

GPS 1PPS Synchronized to UTC

ANT DLY 120 ns

Position

MODE

Survey: 17.5% complete

AVG LAT N 37:19:32.264

AVG LON W 121:59:52.112

AVG HGT

......................................................

+41.86 m (GPS)

[ OK ]

ELEV MASK 10 deg

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

OCXO: OK EFC: OK GPS Rcv: OK

Figure 3-6. Sample Status Screen

The status screen has three major sections:

• SYNCHRONIZATION

• ACQUISITION

• HEALTH MONITOR

The SYNCHRONIZATION section of the status screen shows how the

GPS Receiver’s SmartClock technology is progressing towards its

objective, which is to synchronize the Receiver’s oscillator to the 1 PPS

reference signal produced by the Receiver’s internal GPS Engine.

The ACQUISITION section of the status screen shows how the

Receiver’s internal GPS Engine is progressing towards its objective,

which is to produce an accurate internal 1 PPS reference signal. It does

so through tracking GPS satellites.

The HEALTH MONITOR section of the status screen summarizes the

overall health of the product.

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Chapter 3 Visual User Interface

Receiver Status Screen Data

SYNCHRONIZATION Section of the Status Screen

SYNCHRONIZATION Summary Line

The SYNCHRONIZATION line in the screen summarizes the

SmartClock Status and Reference Outputs. One of three

SYNCHRONIZATION messages is shown:

Outputs Invalid

Outputs Valid/

while the Receiver (unit) is warming up,

Reduced Accuracy while the unit is in holdover or is locked but has

not achieved steady-state operation, or

Outputs Valid

while the unit is in steady-state operation.

SmartClock Mode

The SmartClock Mode area of the screen shows the four operating

modes:

• Locked to GPS

• Recovery

• Holdover

• Power-up

As shown in the sample status screen in Figure 3-6, a >> symbol

indicates the current operating mode.

Locked to GPS indicates that the Receiver is locked to GPS. The

front-panel GPS Lock LED will be illuminated.

When stabilizing frequency ... is shown, the time output (1 PPS) signal is

locked and can be used, but the frequency outputs (10 MHz) are not at

their final or most stable state.

Recovery indicates that the Receiver is actively working to become

locked to GPS. All conditions needed to proceed towards a lock have

been met. Expect an eventual spontaneous transition to a lock (unless

changing external conditions prevent this, such as loss of tracked

satellites.)

Holdover indicates that the Receiver is waiting for conditions that are

needed to allow the process of recovery from holdover to begin. Once

these conditions are met, the Receiver will transition on its own to the

recovery mode.

When the GPS 1PPS CLK invalid message follows the Holdover label,

the internal GPS 1 PPS reference signal is inaccurate.

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Chapter 3 Visual User Interface

Receiver Status Screen Data

When the manually initiated message follows the Holdover label, the

Receiver has been placed in holdover by the user. An explicit command

is required to initiate an exit from manual holdover.

When the 1 PPS TI exceeds hold threshold message follows the

Holdover label, the phase difference between the 1 PPS time output

signal and the internal GPS 1 PPS reference signal has exceeded the

user-entered holdover threshold value.

When the internal hardware problem message follows the Holdover

label, a measurement hardware error exists.

The Holdover Duration message indicates the duration that the Receiver

has been operating in holdover (and recovery). Thus, this message

gives you an assessment of the quality of the outputs. The longer the

Receiver is in holdover the more degraded the outputs become.

Power-up indicates that the Receiver hasn’t yet achieved GPS lock or

acquired satellites since it has been powered up. The Receiver is

measuring the internal reference oscillator’s frequency and adjusting it

to 10 MHz during this power-up period. Other queries can provide

insight as to the cause if the Receiver is remaining in powerup longer

than expected.

Reference Outputs

TFOM (Time Figure of Merit) indicates the accuracy of the Receiver’s

internal 1 PPS signal. A low TFOM value indicates a more accurate

signal. In the sample screen of Figure 3-6, a value of 3 is displayed,

meaning that the Time Error ranges from 100 to 1000 nanoseconds.

The following table lists the TFOM values that could be displayed and

the corresponding Time Error.

Time Error

TFOM Value (in nanoseconds)

Time Error

(in nanoseconds)

TFOM Value

less than 1

1 – 10

10⁴– 10⁵

10⁵– 10⁶

10 – 100

100 – 1000

10³– 10⁴

10⁶– 10⁷

10⁷– 10⁸

greater than 10⁸

*^{The TFOM values 0, 1, and 2 are not presently used in the Receiver. The Receiver will display}

TFOM values ranging from 9 to 3, which is consistent with the specified accuracies of each product.

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Chapter 3 Visual User Interface

Receiver Status Screen Data

FFOM (Frequency Figure of Merit) indicates the stability of the

Receiver’s internal 10 MHz signal. The 10 MHz signal is controlled by

the SmartClock’s Phase-Locked Loop (PLL). Thus, the FFOM value is

determined by monitoring the status of the PLL.

In the sample screen of Figure 3-6, the 0 indicates that the

SmartClock’s PLL is stabilized. The following table lists and defines

the FFOM values that could be displayed.

FFOM Value Definition

PLL stabilized — internal 10 MHz signal within

specification.

PLL stabilizing

PLL unlocked (holdover) — Initially the 10 MHz signal

will be within specifications. However, when in holdover,

the 10 MHz signal will eventually drift out of

specification.

PLL unlocked (not in holdover) — Do not use the output.

1PPS TI indicates the difference (timing shift) between the SmartClock

1 PPS and the internal GPS 1 PPS signals.

HOLD THR (holdover threshold) displays the user-entered time error

value.

ACQUISITION Section of the Status Screen

ACQUISITION Line

The ACQUISITION line in the screen summarizes the state of the

internal GPS Engine as indicated by the Tracking, Not Tracking, and

Position areas of the screen.

If the Receiver Engine was considered to be synchronized to the GPS

signal, the [GPS 1 PPS Valid] message will appear at the end of the

ACQUISITION line. If the Receiver has not yet synchronized to GPS,

the [GPS 1 PPS CLK Invalid] message will be displayed.

Tracking, Not Tracking

The Tracking table indicates the number of satellites the Receiver is

tracking.

The Not Tracking table indicates satellites predicted to be visible that

are not tracked, and all of the satellites that are assigned to a GPS

Engine channel but are not currently tracked.

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Receiver Status Screen Data

Health and status indicators in the tables are defined as follows:

PRN

indicates the pseudorandom noise code assigned to the

satellite.

indicates the predicted elevation angle, from a range of 0

to 90°. The predicted elevation is derived from the

almanac.

- -

indicates that the elevation angle is unknown (the

almanac did not provide this data).

indicates the predicted azimuth angle, from a range of 0

to 359°. The predicted azimuth angle is referenced to true

north, and is derived from the almanac.

- - -

indicates that the azimuth angle is unknown (the

almanac did not provide this data).

C/N

(58503B)

indicates the carrier-to-noise ratio of the received the

signal, from a range of 26 to 55. A ratio below 35 is a

weak signal that may not be acquired by the Receiver.

indicates the strength of the signal, from a range of 0 to

255. A signal strength of 20 to 30 is a weak signal that

may not be acquired by the Receiver.

(59551A)

The health and status indicators in the Not Tracking table are

described as follows:

Ignore

Not OK

Acq

indicates that the user has chosen to exclude this

satellite from a list of satellites available for tracking.

indicates GPS has reported that this satellite is

unhealthy.

indicates the unit is attempting to acquire the satellite

signal.

Acq .

indicates the unit is reading timing information from

the satellite.

Acq . .

indicates the unit is reading satellite orbital

information.

ELEV MASK indicates the elevation mask angle in degrees. Satellites

at or above this elevation angle are considered for

tracking.

*attempting

to track

indicates that the Receiver is attempting to track a

satellite.

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Receiver Status Screen Data

Time

When you first power up the unit the time and date that is stored in

the internal GPS Engine may not be the actual date. The actual time

and date will be valid after one satellite has been tracked by the

Receiver.

NOTE

There are two accurate ways to express time (GPS or UTC). GPS time

is offset from UTC time by the number of accumulated leap seconds

since midnight of January 6, 1980 UTC.

The Time area of the status screen provides three types of information:

Time, 1PPS CLK, and ANT DLY.

Time has four possible modes: GPS, UTC, LOCL GPS, and LOCAL.

GPS indicates current time and date collected from a satellite in GPS

Time.

LOCL GPS indicates GPS Time, offset for the local time zone.

UTC indicates current time and date collected from a satellite in UTC

time.

LOCAL indicates current time and date collected from a satellite offset

from UTC for the local time zone.

1PPS CLK can indicate several possible advisory messages. These

messages are:

Synchronized 1 PPS locked to GPS, referenced to GPS Time.

to GPS Time

Synchronized 1 PPS locked to GPS, referenced to UTC.

To UTC

Assessing

stability ...

applying hysteresis to locked 1 PPS signal.

not tracking satellites.

Inaccurate,

not tracking

Inaccurate,

in survey mode, but has not yet calculated a position.

inacc position

Absent or freq no 1PPS signal; or the internal GPS Engine is idle.

incorrect

3-16

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Chapter 3 Visual User Interface

Receiver Status Screen Data

ANT DLY (antenna delay) displays the user-entered value that is used

to compensate for the propagation delay of the antenna cable.

Position

Position area of the status screen provides four types of information:

MODE (hold or survey), LAT (latitude), LON (longitude), and HGT

(height).

MODE indicates whether the unit is set to Hold or Survey position

mode.

When Hold is displayed, the unit’s antenna position has been provided

by the user, or the average position has been found after completion of

survey.

If the unit is in the position Hold mode, the LAT, LON, and HGT “held”

position coordinates will be displayed.

If Survey: 57.3% complete is displayed, for example, the Receiver is

set to survey mode trying to determine the position of the antenna. The

% value indicates the progress of the surveying.

At the beginning of a survey (0% completion), the following “estimated”

position coordinates will be displayed:

INIT LAT indicates the estimated latitude (North or South) position of

the unit in degrees, minutes, and seconds.

INIT LON indicates the estimated longitude (East or West) position of

the unit in degrees, minutes, and seconds.

INIT HGT indicates estimated height of the unit’s antenna, in meters

above the GPS ellipsoid for 58503B (in meters above mean sea level,

MSL, for the 59551A).

Once survey starts, the following “averaged” position coordinates will

be displayed:

AVG LAT indicates the average latitude (North or South) position of the

unit in degrees, minutes, and seconds.

AVG LON indicates the average longitude (East or West) position of the

unit in degrees, minutes, and seconds.

AVG HGT indicates average height of the unit’s antenna, in meters

above the GPS ellipsoid for 58503B (in meters above mean sea level,

MSL, for the 59551A).

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Chapter 3 Visual User Interface

Receiver Status Screen Data

The possible advisory messages that can be displayed when position

mode is Survey are:

Suspended: track <4 sats

Suspended: poor geometry

Suspended: no track data

HEALTH MONITOR Section of the Screen

The HEALTH MONITOR section of the status screen reports errors or

failures of the key hardware functions. The OK summary message at

the end of the HEALTH MONITOR line indicates that no errors or

failures were detected. Error indicates that one or more hardware tests

failed.

For each hardware function, OK is reported when it is operating

normally; Err is displayed when a failure or an error is detected.

Hardware functions are monitored periodically, with the exception of

Self Test, which is performed at powerup or when requested.

The health and status indicators in the HEALTH MONITOR section

are described as follows:

Self Test

Last diagnostic check of the microprocessor system,

reference oscillator, satellite receiver, and power

supplies failed.

Int Pwr

Oven Pwr

OCXO

Internal power supply voltage(s) exceeds tolerance.

Oscillator oven power supply voltage exceeds tolerance.

Oscillator output failed.

EFC

Oscillator control voltage is at or near full-scale.

GPS Rcv

Satellite receiver communication failed, or GPS 1PPS

reference is absent.

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Receiver Status Screen Data

This Page Intentionally Left Blank.

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Chapter 3 Visual User Interface

The Receiver Status Screen at a Glance

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Chapter 3 Visual User Interface

The Receiver Status Screen at a Glance

The Receiver Status Screen at a Glance (cont’d)

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Chapter 3 Visual User Interface

The Receiver Status Screen at a Glance

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Command Quick Reference

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Chapter 4 Command Quick Reference

Chapter Contents

This chapter is a quick reference that summarizes the GPS Receiver

commands which allow you to operate and program the Receiver.

This chapter is organized as follows:

• An Introduction to GPS Receiver Commands

page 4-4

page 4-5

page 4-6

page 4-7

page 4-8

page 4-9

–

SCPI Conformance Information

Command Syntax Conventions

Command Presentation

• GPS Satellite Acquisition

–

Facilitating Initial Tracking

Establishing Position

Selecting Satellites

Compensating for Antenna Delay

Monitoring Acquisition

• 1 PPS Reference Synchronization

–

Monitoring 1 PPS Synchronization

Assessing 1 PPS Quality

Operating in Holdover

• Operating Status

–

Receiver Operation at a Glance

Reading the Error Queue

Reading the Diagnostic Log

Monitoring Status/Alarm Conditions

Assessing Receiver Health

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Chapter 4 Command Quick Reference

Chapter Contents

• System Time

page 4-10

–

Identifying Time of Next 1 PPS Reference Edge

Reading Current Time

Applying Local Time Zone Offset

Defining the 1 PPS Reference Edge (59551A Only) page 4-10

Reading Leap Second Status

page 4-10

page 4-11

page 4-12

page 4-13

page 4-14

page 4-15

page 4-17

• Programmable Pulse Output (59551A Only)

• Event Time Stamping (59551A Only)

–

Defining the Time-stamped Edge

Clearing Time Stamp Memory

Reading Time Stamps

Processing Memory Overflow

• Serial Interface Communication

–

Configuring I/O Port 1

Configuring I/O Port 2 (59551A Only)

Recovering the Last Query Response

• Receiver Initialization

• Receiver Identification/Upgrade

–

Reading Product Identification

Installing Firmware via I/O Port 1

• Receiver Commands at a Glance (cont’d)/Status

Reporting System at a Glance (foldout)

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Chapter 4 Command Quick Reference

An Introduction to GPS Receiver Commands

An Introduction to GPS Receiver

Commands

SCPI Conformance Information

The SCPI commands used in the GPS Receiver are in conformance

with the SCPI Standard Version 1994.0.

Details of all the GPS Receiver commands can be found in Chapter 5,

“Command Reference,” of this guide.

Information on the SCPI commands format, syntax, parameter, and

response types is provided in Appendix B, “Command Syntax and

Style,” of this guide.

Command Syntax Conventions

POSition

Means you MUST use either all the upper case letters or

the entire word. The lower case letters are optional.

For example, POS and POSITION are both valid.

However, POSI is not valid. (Note: POSition is used here

as an example, but this convention is true for all

command keywords.) In other words, the short form of

the keywords is shown in uppercase.

NOTE

When you see quotation marks in the command’s parameter, you must

send the quotation marks with the command.

Command Presentation

The shaded commands listed in the following sections are the “basic”

(fundamental) or most commonly used commands. These commands

are essential for operating the Receiver; thus, a brief description of

each of these commands is included in this section. More complete

descriptions are provided in Chapter 5, “Command Reference.”

The non-shaded commands listed in this section are not fundamental

or not commonly used. These commands are used for one-time setup,

advanced, or specialized operation of the Receiver. Descriptions of

these commands are provided in Chapter 5 only.

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Chapter 4 Command Quick Reference

GPS Satellite Acquisition

The following commands are provided to facilitate initial GPS satellite

tracking, to establish accurate GPS antenna position, to select or ignore

satellites, to compensate for antenna cable delay, and to monitor the

acquisition.

Facilitating Initial Tracking

:GPS:INITial:DATE <four-digit year>, <month>, <day>

:GPS:INITial:POSition N or S, <latitude degree>,

<latitude minute>,

<latitude second>,

E or W, <longitude degree>,

<longitude minute>,

<longitude second>,

:GPS:INITial:TIME <hour>, <minute>, <second>

Establishing Position

:GPS:POSition

N or S, <latitude degree>,

<latitude minute>,

<latitude second>,

E or W, <longitude degree>,

<longitude minute>,

<longitude second>,

Specifies the position of the GPS antenna.

:GPS:POSition?

Returns the current average position of the GPS antenna.

:GPS:POSition:ACTual?

Returns the current instantaneous position of the GPS antenna.

:GPS:POSition LAST

:GPS:POSition SURVey

:GPS:POSition:HOLD:LAST?

:GPS:POSition:HOLD:STATe?

:GPS:POSition:SURVey:PROGress?

:GPS:POSition:SURVey:STATe ONCE

:GPS:POSition:SURVey:STATe?

:GPS:POSition:SURVey:STATe:POWerup ON or OFF

:GPS:POSition:SURVey:STATe:POWerup?

Basic command

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Chapter 4 Command Quick Reference

GPS Satellite Acquisition

Selecting Satellites

<select> = IGNore or INCLude

:GPS:SATellite:TRACking:EMANgle <degrees>

Sets the GPS elevation mask angle value.

:GPS:SATellite:TRACking:EMANgle?

Returns the GPS elevation mask angle value.

:GPS:SATellite:TRACking:IGNore <PRN>, ... , <PRN>

(59551A)

Sends list of satellites to ignore.

:GPS:SATellite:TRACking:IGNore?

Returns list of satellites to ignore.

:GPS:SATellite:TRACking:INCLude <PRN>, ... , <PRN> (59551A)

:GPS:SATellite:TRACking:INCLude?

(59551A)

:GPS:SATellite:TRACking:<select>:ALL

:GPS:SATellite:TRACking:<select>:COUNt?

:GPS:SATellite:TRACking:<select>:NONE

:GPS:SATellite:TRACking:<select>:STATe? <PRN>

Compensating for Antenna Delay

:GPS:REFerence:ADELay <seconds>

Sets the GPS antenna delay value in seconds.

:GPS:REFerence:ADELay?

Returns the GPS antenna delay value in seconds.

Monitoring Acquisition

:GPS:REFerence:VALid?

Indicates whether the date and time are valid (1 = valid).

:GPS:SATellite:TRACking?

Returns a list of all satellites being tracked.

:GPS:SATellite:VISible:PREDicted?

Returns the list of satellites (PRN) that the almanac predicts should be visible, given date, time, and

position.

:GPS:SATellite:TRACking:COUNt?

:GPS:SATellite:VISible:PREDicted:COUNt?

Basic command

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Chapter 4 Command Quick Reference

1 PPS Reference Synchronization

The following commands are provided to monitor the operating mode of the

reference oscillator, to determine the accuracy and stability of the reference

output signal(s), and to control the oscillator holdover process.

Monitoring 1 PPS Synchronization

:SYNChronization:STATe?

Returns the Receiver state.

:DIAGnostic:ROSCillator:EFControl:RELative?

:LED:GPSLock?

:LED:HOLDover?

Assessing 1 PPS Quality

:SYNChronization:FFOMerit?

Returns the Frequency Figure of Merit.

:SYNChronization:HOLDover:TUNCertainty:PREDicted?

Returns an estimate of the time error that can be expected for a one day holdover, given

the current state of SmartClock learning in the Receiver.

:SYNChronization:HOLDover:TUNCertainty:PRESent?

Returns the current time interval error at any time during holdover operation, given the

current state of SmartClock learning in the Receiver.

:SYNChronization:TFOMerit?

Returns the Time Figure of Merit.

:SYNChronization:TINTerval?

Returns the difference or timing shift between the SmartClock 1 PPS and the

GPS 1 PPS signals.

:SYNChronization:HOLDover:DURation?

:SYNChronization:HOLDover:DURation:THReshold <seconds>

:SYNChronization:HOLDover:DURation:THReshold?

:SYNChronization:HOLDover:DURation:THReshold:EXCeeded?

Operating in Holdover

Initiating Manual Holdover

:SYNChronization:HOLDover:INITiate

Recovering from Holdover

:SYNChronization:HOLDover:WAITing?

Returns prioritized reason why the Receiver is waiting to recover.

:SYNChronization:HOLDover:RECovery:INITiate

:SYNChronization:HOLDover:RECovery:LIMit:IGNore

:SYNChronization:IMMediate

Basic command

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Chapter 4 Command Quick Reference

Operating Status

The following commands are provided to obtain Receiver status information.

There are several ways to obtain Receiver status using commands.

For example, you can send a command to display the Receiver Status screen,

to read the error queue, and to read the diagnostic log. You can also send a

sequence of commands to read and control the status registers for alarm

generation.

Receiver Operation at a Glance

:SYSTem:STATus?

Outputs a fully formatted status screen.

:SYSTem:STATus:LENGth?

Reading the Error Queue

:SYSTem:ERRor?

Returns the oldest error in the Error Queue and removes that error from the queue (first in, first out).

Reading the Diagnostic Log

:DIAGnostic:LOG:CLEar

Clears the diagnostic log.

:DIAGnostic:LOG:READ:ALL?

Returns all of the most recent diagnostic log entries.

:DIAGnostic:LOG:CLEar <current log size>

:DIAGnostic:LOG:COUNt?

:DIAGnostic:LOG:READ?

:DIAGnostic:LOG:READ? <entry number>

Monitoring Status/Alarm Conditions

Clearing and Presetting Alarms

*CLS

Clears the event status registers and error queue.

:STATus:PRESet:ALARm

Reading and Qualifying Alarms

:LED:ALARm?

Returns status of front-panel Alarm LED.

*SRE <bit mask>

*SRE?

*STB?

Basic command

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Chapter 4 Command Quick Reference

Operating Status

Reading and Qualifying Receiver Status

<register> = OPERation

<register> = QUEStionable

<register> = OPERation:HARDware

<register> = OPERation:HOLDover

<register> = OPERation:POWerup

:STATus:<register>:CONDition?

Returns the Condition Status Register value.

:STATus:<register>:EVENt?

Returns the Event Status Register value.

:STATus:<register>:ENABle <bit mask>

:STATus:<register>:ENABle?

:STATus:<register>:NTRansition <bit mask>

:STATus:<register>:NTRansition?

:STATus:<register>:PTRansition <bit mask>

:STATus:<register>:PTRansition?

Reading and Qualifying Command Error Status

*ESE <bit mask>

*ESE?

*ESR?

Reporting Questionable Status

:STATus:QUEStionable:CONDition:USER SET or CLEar

:STATus:QUEStionable:EVENt:USER PTR or NTR

Assessing Receiver Health

*TST?

Executes an internal selftest and reports the results.

:DIAGnostic:LIFetime:COUNt?

:DIAGnostic:TEST? ALL or DISPlay or PROCessor or RAM or EEPROM or UART or QSPI

or FPGA or INTerpolator or IREFerence or GPS or POWer

:DIAGnostic:TEST:RESult?

Basic command

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Chapter 4 Command Quick Reference

System Time

The following commands are provided to allow you to monitor and control the

system date and time. These commands allow you access to a very accurate

system clock that provides both date and time, to customize the clock for a local

time zone, to identify the exact time, to identify the accumulated time

difference (in seconds) between the GPS and UTC timelines, and to monitor

leap second occurrences.

Identifying Time of Next 1 PPS Reference Edge

^R:PTIMe:TCODe?

Returns timecode message 980 to 20 ms prior to 1 PPS of indicated time.

Reading Current Time

:PTIMe:DATE? or

:PTIMe:TIME? or

:PTIMe:TIME:STRing?

:SYSTem:DATE?

:SYSTem:TIME?

Applying Local Time Zone Offset

:PTIMe:TZONe <hours>, <minutes>

Sets the time zone local time offset to provide an offset from UTC to serve as the basis for all

reported time.

:PTIMe:TZONe?

Returns the local time zone offset.

Defining the 1 PPS Reference Edge (59551A Only)

:PTIMe:PPS:EDGE RISing or FALLing

Selects the polarity of the 1 PPS on-time edge.

:PTIMe:PPS:EDGE?

Returns the polarity of the 1 PPS on-time edge.

Reading Leap Second Status

:PTIMe:LEAPsecond:ACCumulated?

Returns the leap second difference accumulated between GPS time and UTC time since the beginning

of GPS time. The time units are seconds.

:PTIMe:LEAPsecond:DATE?

:PTIMe:LEAPsecond:DURation?

:PTIMe:LEAPsecond:STATe?

Basic command

R: Accessible via rear-panel PORT 1.

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Chapter 4 Command Quick Reference

Programmable Pulse Output (59551A Only)

Programmable Pulse Output (59551A

Only)

The following commands are provided to allow you to operate and control the

programmable pulse output of the 59551A GPS Receiver. The pulse output,

which is programmable by the user, can either generate a stream of pulses at

a specified start time and repetition interval, or can produce a single pulse at

a specified time and then stop.

:PULSe:CONTinuous:PERiod <seconds>

Sets the interval between pulses in seconds.

:PULSe:CONTinuous:PERiod?

Returns the interval between pulses in seconds.

:PULSe:CONTinuous:STATe ON or OFF

Selects whether the Programmable Pulse output will be just one pulse or a sequence of pulses.

:PULSe:CONTinuous:STATe?

Identifies whether the Programmable Pulse output is set to output a single pulse or

sequence of pulses.

:PULSe:REFerence:EDGE RISing or FALLing

Selects the polarity of the Programmable Pulse on-time edge.

:PULSe:REFerence:EDGE?

Returns the polarity of the Programmable Pulse on-time edge.

:PULSe:STARt:DATE <four-digit year>, <month>, <day>

Sets the date when the individual pulse (or first pulse of the pulse sequence) is to be generated at the

Programmable Pulse output.

:PULSe:STARt:DATE?

Returns the date when the individual pulse (or first pulse of the pulse sequence) is generated at the

Programmable Pulse output.

:PULSe:STARt:TIME <hour>, <minute>, <second>

Sets the time when the individual pulse (or first pulse of the pulse sequence) is to be generated at the

Programmable Pulse output.

:PULSe:STARt:TIME?

Returns the time when the individual pulse (or first pulse of the pulse sequence) is generated at the

Programmable Pulse output.

Basic command

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Chapter 4 Command Quick Reference

Event Time Stamping (59551A Only)

The following commands are provided to allow you to time-tag and record

events such as power surges and power outages. The time tagging input

feature allows you to use the Receiver with equipment which produce a TTL

edge when some important event happens in the base station. The Receiver has

three time tagging inputs which record the time of occurrence of TTL edge(s).

Defining the Time-stamped Edge

<channel> = 1 or 2 or 3

:SENSe:TSTamp<channel>:EDGE RISing or FALLing

Selects the polarity of the edges the Receiver will timestamp.

:SENSe:TSTamp<channel>:EDGE?

Returns the polarity of the edges the Receiver will timestamp.

Clearing Time Stamp Memory

:SENSe:DATA:CLEar

Clears the data in the measurement buffer for all Time Tag inputs.

:SENSe:DATA:CLEar "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Reading Time Stamps

:SENSe:DATA? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Returns the data in the timestamp measurement buffer for the specified Time Tag input.

:FORMat:DATA ASCii or INTeger

:FORMat:DATA?

:SENSe:DATA:POINts?

:SENSe:DATA:POINTs? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

:SENSe:DATA:TSTamp? "TSTamp 1" or "TSTamp 2" or "TSTamp 3", <entry number>

Processing Memory Overflow

:SENSe:DATA:MEMory:OVERflow:COUNt?

:SENSe:DATA:MEMory:OVERflow:COUNt? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

:SENSe:DATA:MEMory:SAVE FIRST or LAST

:SENSe:DATA:MEMory:SAVE?

Basic command

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Chapter 4 Command Quick Reference

Serial Interface Communication

The following commands are provided to allow you to configure the serial

interface port(s) for instrument communications.

Configuring I/O Port 1

:SYSTem:COMMunicate?

:SYSTem:COMMunicate:SERial1:BAUD 1200 or 2400 or 9600 or 19200

^R,F:SYSTem:COMMunicate:SERial1:BAUD?

:SYSTem:COMMunicate:SERial1:BITS 7 or 8

^R,F:SYSTem:COMMunicate:SERial1:BITS?

:SYSTem:COMMunicate:SERial1:FDUPlex ON or OFF

^R,F:SYSTem:COMMunicate:SERial1:FDUPlex?

:SYSTem:COMMunicate:SERial1:PACE XON or NONE

^R,F:SYSTem:COMMunicate:SERial1:PACE?

:SYSTem:COMMunicate:SERial1:PARity EVEN or ODD or NONE

^R,F:SYSTem:COMMunicate:SERial1:PARity?

:SYSTem:COMMunicate:SERial1:SBITs 1 or 2

(59551A)

^R,F:SYSTem:COMMunicate:SERial1:SBITs?

Configuring I/O Port 2 (59551A Only)

:SYSTem:COMMunicate?

:SYSTem:COMMunicate:SERial2:BAUD 1200 or 2400 or 9600 or 19200

^R,F:SYSTem:COMMunicate:SERial2:BAUD?

^R,F:SYSTem:COMMunicate:SERial2:BITS?

:SYSTem:COMMunicate:SERial2:FDUPlex ON or OFF

^R,F:SYSTem:COMMunicate:SERial2:FDUPlex?

:SYSTem:COMMunicate:SERial2:PACE XON or NONE

^R,F:SYSTem:COMMunicate:SERial2:PACE?

:SYSTem:COMMunicate:SERial2:PARity EVEN or ODD or NONE or ONE

^R,F:SYSTem:COMMunicate:SERial2:PARity?

^R,F:SYSTem:COMMunicate:SERial2:SBITs?

Recovering the Last Query Response

:DIAGnostic:QUERy:RESPonse?

Basic command

R: Accessible via rear-panel PORT 1.

F: Accessible via Front-panel PORT 2 of the 59551A

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Chapter 4 Command Quick Reference

Receiver Initialization

The following commands are provided to allow you to initialize or preset the

serial interface port(s) and the Receiver to their factory shipment values.

^R:SYSTem:COMMunicate:SERial1:PRESet

:SYSTem:COMMunicate:SERial2:PRESet (59551A Only)

:SYSTem:PRESet

Basic command

R: Accessible via Rear-panel PORT 1.

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Chapter 4 Command Quick Reference

Receiver Identification/Upgrade

The commands provided in this section allow you to query the identification of

the Receiver, and to perform firmware upgrades in the field after you obtain a

new firmware disk.

Reading Product Identification

*IDN?

Returns the Receiver identification.

Installing Firmware via I/O Port 1

^R*CLS

^R:DIAGnostic:DOWNload <Motorola S-record>

^R:DIAGnostic:ERASe

^R:DIAGnostic:ERASe?

^R:SYSTem:ERRor?

^R:SYSTem:LANGuage "INSTALL" or "PRIMARY"

^R:SYSTem:LANGuage?

Basic command

R: Accessible via Rear-panel Port 1.

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Chapter 4 Command Quick Reference

Receiver Identification/Upgrade

Receiver Commands at a Glance

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Chapter 4 Command Quick Reference

Receiver Identification/Upgrade

Receiver Commands at a Glance (cont’d)

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Chapter 4 Command Quick Reference

Status Reporting System at a Glance

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Command Reference

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Chapter 5 Command Reference

Chapter Contents

This chapter provides a description of each command that can be used

to operate the GPS Receiver. The commands are grouped by functions.

The functions are grouped and ordered the same as they are in

Chapter 4, “Command Quick Reference,” and on the foldout “Receiver

Commands at a Glance (cont’d).”

This chapter is organized as follows:

• Command Syntax Conventions

• Description Format

page 5-4

page 5-5

–

Commands and Returns

page 5-5

Query-Specific Information

page 5-6

• GPS Satellite Acquisition

page 5-7

–

Facilitating Initial Tracking

Establishing Position

page 5-9

page 5-12

page 5-17

page 5-22

page 5-24

page 5-27

page 5-28

page 5-30

page 5-36

page 5-39

page 5-41

page 5-42

page 5-43

page 5-48

page 5-70

Selecting Satellites

Compensating for Antenna Delay

Monitoring Acquisition

• 1 PPS Reference Synchronization

–

Monitoring 1 PPS Synchronization

Assessing 1 PPS Quality

Operating in Holdover

• Operating Status

–

Receiver Operation at a Glance

Reading the Error Queue

Reading the Diagnostic Log

Monitoring Status/Alarm Conditions

Assessing Receiver Health

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Chapter 5 Command Reference

Chapter Contents

• System Time

page 5-73

page 5-74

page 5-75

page 5-77

–

Identifying Time of Next 1 PPS Reference Edge

Reading Current Time

Applying Local Time Zone Offset

Defining the 1 PPS Reference Edge (59551A Only) page 5-78

Reading Leap Second Status

page 5-79

page 5-83

page 5-89

page 5-90

page 5-91

page 5-92

page 5-97

page 5-100

page 5-101

page 5-108

page 5-109

page 5-113

page 5-114

page 5-115

• Programmable Pulse Output (59551A Only)

• Event Time Stamping (59551A Only)

–

Defining the Time-stamped Edge

Clearing Time Stamp Memory

Reading Time Stamps

Processing Memory Overflows

• Serial Interface Communication

–

Configuring I/O Ports

Recovering the Last Query Response

• Receiver Initialization

• Receiver Identification/Upgrade

–

Reading Product Identification

Installing Firmware via I/O Port 1

See Appendix B, “Command Syntax and Style,” for details regarding

command Expanded Syntax, parameter types, and query response

types.

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Chapter 5 Command Reference

Command Syntax Conventions

POSition

Means you MUST use either all the uppercase letters or

the entire word. The lowercase letters are optional. For

example, POS and POSITION are both valid. However,

POSI is not valid. (Note POSition is used here as an

example, but this convention is true for all command

keywords.) In other words, the short form of the

keywords is shown in uppercase.

<n>

The notation <n> ending a command keyword indicates

a numeric suffix, used to differentiate multiple

instances of the same structure. The numeric suffix is

applied to both the short and long forms. The valid

range for the value n is specified from an enumerated

list, for example [1|2|3], or from a range, for example

[1..3] to indicate any of the integers from 1 to 3.

"TSTamp 1" When you see quotation marks in the command’s

parameter, you must send the quotation marks with the

command.

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Chapter 5 Command Reference

Description Format

Commands and Returns

Product Compatibility

(if not present, the command is

supported by both products)

Command Index

Default Setting

(commands only)

Required characters are shown

in bold type. "..." denotes one

or more parameters; refer to

Expanded Syntax for details.

HP 59551A

Scope

(commands only)

:SYSTem:PRESet

:PULSe:STARt:DATE . . .

Identifies a "basic"

(fundamental) command.

1994,1,1

Identifies the date when the individual p

the pulse sequence) is generated at th

output.

Synopsis

NON-VOLATILE

This command identifies the date when

the pulse sequence) is generated at the Pr

Description

Command Mnemonic

Consult Appendix B: Command

Syntax and Style for notational style.

Expanded Syntax

:PULSe:STARt:DATE <four-digit year

Allowed Values,

Range and Resolution

Parameter

The <four-digit year> range is 1994 to

The <month> range is 1 to 12.

The <day> range is 1 to 31.

When the command may

be issued

Context Dependencies

If you select a date and time which occu

the completion of powerup and first GPS

successfuly find a start – and therefore w

If the Receiver has been set up to use a t

and time, the parameters provided should

time.

:SYSTem:PRESet sets the date to January

Side Effects

Secondary effects on

other functions.

Concepts

Theory

Indicates that you cautiously use the :SYSTem:COMMunicate:SERIAL

commands to change the Receiver's serial interface parameters (i.e., BAUD, BITS,

PACE, PARity, and SBITs) from their factory default values. It is recommended that

you configure your PC's serial port settings to match the Receiver's factory default

values instead. However, if you must change the parameters, be sure to write down or

record all changes. Refer to Chapter 2, "Serial Interface Capabilities," in this guide for

more information.

This command can be executed

via the rear-panel PORT 1 only.

:SYSTem:PRESet

Not affected

:SYSTem:COMMunicate:SERial:BAUD . . .

Sets the baud rate of PORT 1.

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Chapter 5 Command Reference

Description Format

Query-Specific Information

Description of Response Formats (ASCII-encoded)

The following legend provides the meaning of each type of response

format. Refer to Table B-3 in Appendix B, “Command Syntax and

Style,” for details.

RESPONSE FORMAT Example

Description

0 or 1

Single character,

one or zero

d.d

+10

Integer

+1.5

Fixed-point number

Floating-point number

Alphanumeric characters

Quoted string

d.dEe

XYZ

+1.00000E-009

LOCK

“ XYZ ”

dd, ...

“19:49:51” or “No error”

+14, +15, +18, +22, +29

Comma-separated list of

integers

“ XYZ”, ...

“Log 001:19950101.00:00:00: Power on”,

Comma-separated list of

“Log 002:19950101.00:10:00: Log cleared” quoted strings

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Chapter 5 Command Reference

GPS Satellite Acquisition

The GPS Receiver is designed to acquire time transfer information (time, date,

and position) from the GPS satellites, which is used by the Receiver’s internal

reference oscillator and SmartClock technology to lock to GPS. It acquires a

precise time and date by tracking at least one satellite. By tracking at least four

satellites, it precisely determines the position of the antenna. With this

information, the Receiver can produce a precise 1 PPS signal that is exactly

synchronous to Coordinated Universal Time (UTC) as determined by GPS.

The following commands are provided to facilitate initiate GPS satellite

tracking, to establish accurate GPS antenna position, to select or ignore

satellites, to compensate for antenna cable delay, and to monitor the

acquisition.

! Facilitating Initial Tracking

:GPS:INITial:DATE ...

:GPS:INITial:POSition ...

:GPS:INITial:TIME ...

! Establishing Position

:GPS:POSition ...

:GPS:POSition?

:GPS:POSition:ACTual?

:GPS:POSition:HOLD:LAST?

:GPS:POSition:HOLD:STATe?

:GPS:POSition:SURVey:PROGress?

:GPS:POSition:SURVey:STATe ...

:GPS:POSition:SURVey:STATe?

:GPS:POSition:SURVey:STATe:POWerup ...

:GPS:POSition:SURVey:STATe:POWerup?

! Selecting Satellites

:GPS:SATellite:TRACking:EMANgle ...

:GPS:SATellite:TRACking:EMANgle?

:GPS:SATellite:TRACking:IGNore ...

:GPS:SATellite:TRACking:IGNore?

:GPS:SATellite:TRACking:INCLude ...

:GPS:SATellite:TRACking:INCLude?

:GPS:SATellite:TRACking:<select>:ALL

:GPS:SATellite:TRACking:<select>:COUNt?

(59551A)

:GPS:SATellite:TRACking:<select>:STATe? ...

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Chapter 5 Command Reference

GPS Satellite Acquisition

! Compensating for Antenna Delay

:GPS:REFerence:ADELay ...

:GPS:REFerence:ADELay?

! Monitoring Acquisition

:GPS:REFerence:VALid?

:GPS:SATellite:TRACking?

:GPS:SATellite:VISible:PREDicted?

:GPS:SATellite:TRACking:COUNt?

:GPS:SATellite:VISible:PREDicted:COUNt?

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Chapter 5 Command Reference

GPS Satellite Acquisition

Facilitating Initial Tracking ______________________________

:SYSTem:PRESet

:GPS:INITial:DATE . . .

Sets an approximate date for faster initial GPS acquisition.

Not affected

VOLATILE

This command sets an approximate date for faster initial GPS acquisition.

Following powerup, the Receiver obtains the current date from satellite data.

This process occurs automatically. Providing an approximate date, however,

reduces the time to initial GPS tracking by assisting the Receiver in finding

satellites.

Expanded Syntax

:GPS:INITial:DATE <four-digit year>,<month>,<day>

Parameter

Range: the year, month, and day must be valid.

Context Dependencies

This command is valid prior to first satellite tracked (see bit 0 of the Operation

Status Register). Sending this command after this time will generate

error -221.

The initial date and time needs to be within 3 minutes of the actual date and

time to be effective in enabling faster initial GPS acquisition.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Facilitating Initial Tracking ____________________ (continued)

:SYSTem:PRESet

:GPS:INITial:POSition . . .

Sets an approximate position for faster initial GPS acquisition.

:Not affected

VOLATILE

This command sets an approximate position for faster initial GPS acquisition.

Following powerup, the Receiver refines its position from the satellite data.

This process occurs automatically. This command is most effective when the

retained position differs significantly from the Receiver’s true position.

Expanded Syntax

:GPS:INITial:POSition N or S, <latitude degree>,

<latitude minute>,

<latitude second>,

E or W, <longitude degree>,

<longitude minute>,

<longitude second>,

Parameter

This command requires three position coordinates: latitude, longitude, and

height. Position must be specified with respect to the World Geodetic System

1984 (WGS-1984) datum absolute earth coordinates.

The latitude coordinate is preceded by either N or S, which denotes the

northern or southern hemisphere, respectively. The longitude coordinate is

preceded by either E or W, which denotes the eastern or western hemisphere,

respectively.

The following table lists the allowed settings of other parameters:

Parameter

Range

Precision

Parameter

Range

Precision

<height, m>

0 to 90

<longitude degrees> 0 to 180

<longitude minutes> 0 to 59

<longitude seconds> 0 to 59.999

0 to 59

0 to 59.999

0.001

0.01

0.001

-1000.00 to

18,000.00

Context Dependencies

This command is valid while the Receiver is in survey mode prior to first

computed position. Sending this command while the Receiver is not in survey

mode will generate error -221.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Facilitating Initial Tracking ____________________ (continued)

:SYSTem:PRESet

:GPS:INITial:TIME . . .

Sets an approximate time for faster initial GPS acquisition.

Not affected

VOLATILE

This command sets an approximate time for faster initial GPS acquisition.

Following powerup, the Receiver obtains the current time from satellite data.

This process occurs automatically. Providing an approximate time, however,

reduces the time to initial GPS tracking by assisting the Receiver in finding

satellites.

Expanded Syntax

:GPS:INITial:TIME <hour>,<minute>,<second>

Parameter

Range: all parameters (hour, minutes, seconds) must be valid.

Context Dependencies

This command is valid prior to first satellite tracked (see bit 0 of the Operation

Status Register). Sending this command after this time will generate

error -221.

The initial date and time needs to be within 3 minutes of the actual date and

time to be effective in enabling faster initial GPS acquisition.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position_____________________________________

:SYSTem:PRESet

:GPS:POSition . . .

Defines the position of the Receiver.

latitude:

longitude: E 0:00:00.000

height: 0 meters

N 0:00:00.000

NON-VOLATILE

This command defines the position of the Receiver. The Receiver uses this

position to predict satellite visibility and to determine time. An accurate

position is necessary for precise time transfer.

Expanded Syntax

:GPS:POSition

N or S, <latitude degree>,

<latitude minute>,

<latitude second>,

E or W, <longitude degree>,

<longitude minute>,

<longitude second>,

:GPS:POSition LAST

:GPS:POSition SURVey

Parameter

The numeric form of this command requires three position coordinates:

latitude, longitude, and height. Position must be specified with respect to the

World Geodetic System 1984 (WGS-1984) datum absolute earth coordinates.

The latitude coordinate is preceded by either N or S, which denotes the

northern or southern hemisphere, respectively. The longitude coordinate is

preceded by either E or W, which denotes the eastern or western hemisphere,

respectively.

The following table lists the allowed settings of other parameters:

Parameter

Range

Precision

Parameter

Range

Precision

<height, m>

0 to 90

<longitude degrees> 0 to 180

<longitude minutes> 0 to 59

<longitude seconds> 0 to 59.999

0 to 59

0 to 59.999

0.001

0.01

0.001

-1000.00 to

18,000.00

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Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position ___________________________ (continued)

LAST denotes the last specified position. This parameter is provided to cancel

surveying (automatic position computation) and restore the last position

setting.

SURVey directs the Receiver to stop surveying and use the computed position.

This position is the average of individual position computations.

Context Dependencies

Error -221 is generated if this command is sent as SURV and no valid survey

calculation has ever been computed.

Side Effects

This command stops position surveying. The computed position is retained and

applied only when SURVey is specified.

RESPONSE FORMAT

:GPS:POSition?

Returns the current average position of the GPS antenna.

XYZ or

dd or

d.dEe,

...

This query returns the current average position of the Receiver.

Response

Returns a list of values defining the Receiver position:

N or S, <latitude degree>, <latitude minute>, <latitude second>,

E or W, <longitude degree>,<longitude minute>, <longitude second>,

<height above the GPS ellipsoid, in meters (58303B)> or <height above mean

sea level, in meters (59551A)>.

Context Dependencies

Error -230 is generated if in survey and first calculation has not occurred.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position___________________________ (continued)

RESPONSE FORMAT

:GPS:POSition:ACTual?

Returns the current instantaneous position of the GPS antenna.

XYZ or

dd or

d.dEe,

...

This query returns the current instantaneous position of the GPS antenna.

Response

Returns a list of values defining the Receiver position:

N or S, <latitude degree>, <latitude minute>, <latitude second>,

E or W, <longitude degree>,<longitude minute>, <longitude second>,

<height above the GPS ellipsoid, in meters (58303B)> or <height above mean

sea level, in meters (59551A)>.

Context Dependencies

Error -230 is generated if in survey and first calculation has not occurred.

RESPONSE FORMAT

:GPS:POSition:HOLD:LAST?

Returns the last position-hold setting.

XYZ or

dd or

d.dEe,

...

This query returns the last position-hold setting, which is restored when the

:GPS:POSition LAST command is sent. Refer to the description of the

:GPS:POSition command on page 5-13 for details.

Response

Returns a list of values defining the Receiver position:

N or S, <latitude degree>, <latitude minute>, <latitude second>,

E or W, <longitude degree>,<longitude minute>, <longitude second>,

<height above the GPS ellipsoid, in meters (58303B)> or <height above mean

sea level, in meters (59551A)>.

Context Dependencies

This query is always valid, but if the Receiver has not been in position-hold

mode since it was preset (see :SYSTem:PRESet), the value returned will be the

preset position.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position ___________________________ (continued)

RESPONSE FORMAT

:GPS:POSition:HOLD:STATe?

Identifies whether the Receiver is in position-hold or survey mode.

0 or 1

This query identifies whether the Receiver is in position-hold or survey mode.

In survey mode, the Receiver continually refines its position. In position-hold

mode, the position setting does not change.

Response

A value of 0 indicates not in position hold (in survey mode); a value of 1

indicates in position hold.

RESPONSE FORMAT

:GPS:POSition:SURVey:PROGress?

Returns percent completed while in survey mode.

d.d

This query returns percent completed while in survey mode. Automatic

transition to position-hold mode occurs following completion of survey mode

(indicated by 100).

Response

The range is 0 to 100%. The units are percent.

Context Dependencies

This query is only valid while surveying for position (:GPS:POS:SURV:STATe?

returns ONCE or status bit 3 = 0 in the Operation Status Register). If queried

while not surveying, error -221 is generated.

:SYSTem:PRESet

:GPS:POSition:SURVey:STATe . . .

Initiates survey mode during which the Receiver determines its

position from satellite data.

ONCE

This command initiates survey mode during which the Receiver determines its

position from satellite data. The Receiver refines successive positional

estimates to obtain a final position, transitions from survey to position-hold

mode.

Expanded Syntax

:GPS:POSition:SURVey:STATe ONCE

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Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position___________________________ (continued)

RESPONSE FORMAT

:GPS:POSition:SURVey:STATe?

Identifies whether the Receiver is in survey or position-hold mode.

XYZ or 0

This query identifies whether the Receiver is in survey or position-hold mode.

In survey mode, the Receiver continually refines its position. In position-hold

mode, the position does not change.

Response

A response of ONCE indicates that the Receiver is in survey mode. A response

of 0 indicates the Receiver is in position-hold mode.

:SYSTem:PRESet

:GPS:POSition:SURVey:STATe:POWerup . . .

Selects position mode to be used at powerup.

NON-VOLATILE

This command specifies whether the Receiver always surveys at powerup or

restores its last position at powerup.

Expanded Syntax

:GPS:POSition:SURVey:STATe:POWerup ON or OFF

Parameter

OFF sets the Receiver to powerup in the last valid position. ON sets the

Receiver to survey on powerup.

RESPONSE FORMAT

:GPS:POSition:SURVey:STATe:POWerup?

Returns the position mode to be used at powerup.

0 or 1

This query returns the position mode to be used at powerup.

Response

A value of 0 indicates the Receiver is set to powerup in the last valid position.

A value of 1 indicates the Receiver is set to survey on powerup.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Selecting Satellites _______________________________________

:SYSTem:PRESet

:GPS:SATellite:TRACking:EMANgle . . .

Sets the GPS elevation mask angle value (in degrees).

NON-VOLATILE

This command instructs the Receiver to allow tracking those satellites for

which the elevation angle is greater than this elevation mask angle. Satellites

below this elevation are visible, but will not be tracked.

Expanded Syntax

:GPS:SATellite:TRACking:EMANgle <degrees>

Parameter

<degrees> range is 0 degrees (horizon) to 89 degrees. The resolution is

1 degree.

The maximum recommended value while the position is being surveyed is

15 degrees, to allow tracking of four satellites needed for an accurate position

determination.

Once the survey is complete, the elevation mask angle can be increased to avoid

interference problems caused by buildings and trees and minimize effects of

multipath, if necessary.

Values above 40 degrees severely limit GPS signal availability, and are not

recommended.

RESPONSE FORMAT

:GPS:SATellite:TRACking:EMANgle?

Returns the GPS elevation mask angle value.

This query returns the GPS elevation mask angle value.

Response

The range is 0 degrees to 89 degrees.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Selecting Satellites _____________________________(continued)

59551A

:SYSTem:PRESet

:GPS:SATellite:TRACking:IGNore . . .

Adds the specified satellites to the list that the Receiver ignores

No satellites ignored

for tracking.

NON-VOLATILE

This command adds the specified satellites to the list that the Receiver ignores

for tracking. Each satellite is identified by its pseudorandom noise code (PRN).

Expanded Syntax

:GPS:SATellite:TRACking:IGNore <PRN>, . . ., <PRN>

:GPS:SATellite:TRACking:IGNore:NONE

:GPS:SATellite:TRACking:IGNore:ALL

Parameter

<PRN> parameter is the pseudorandom noise code of the satellite(s) you want

the Receiver to ignore. Each satellite has its own unique PRN.

Context Dependencies

This command is always valid. On send, if any item in the <PRN> list is

invalid, the entire list will be rejected. Error -222 will be generated.

59551A

RESPONSE FORMAT

:GPS:SATellite:TRACking:IGNore?

Returns list of satellites to ignore.

dd, ...

This query returns a list of satellites to ignore for tracking. Each satellite is

identified by its pseudorandom noise code (PRN). Zero (0) indicates no

satellites being ignored.

Response

A value of 0 indicates no satellites being ignored. If any satellite is being

ignored, the pseudorandom noise code (PRN) of the satellite is returned.

Context Dependencies

This query is always valid.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Selecting Satellites _____________________________(continued)

59551A

:SYSTem:PRESet

:GPS:SATellite:TRACking:INCLude . . .

Adds the specified satellites to the list that the Receiver considers

All satellites included

for tracking.

NON-VOLATILE

This command adds the specified satellites to the list that the Receiver

considers for tracking. Actual satellite selection is based on satellite visibility,

geometry, and health.

Expanded Syntax

:GPS:SATellite:TRACking:INCLude <PRN>, . . ., <PRN>

:GPS:SATellite:TRACking:INCLude:NONE

:GPS:SATellite:TRACking:INCLude:ALL

Parameter

<PRN> parameter is the pseudorandom noise code of the satellite(s) you want

the Receiver to include. Each satellite has its own unique PRN.

Context Dependencies

This command is always valid. On send, if any item in the <PRN> list is

invalid, the entire list will be rejected. Error -222 will be generated.

59551A

RESPONSE FORMAT

:GPS:SATellite:TRACking:INCLude?

Returns a list of satellites to include.

dd, ...

This query returns a list of satellites to include for tracking. Each satellite is

identified by its pseudorandom noise code (PRN). Zero (0) indicates no

satellites being included (i.e., the satellites are still on the ignored list).

Context Dependencies

This query is always valid.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Selecting Satellites______________________________ (continued)

RESPONSE FORMAT

:GPS:SATellite:TRACking:IGNore:COUNt?

Returns the number of satellites that are on the list to ignore for

tracking.

:GPS:SATellite:TRACking:INClude:COUNt?

Returns the number of satellites that are on the list to include for

tracking.

The query :GPS:SATellite:TRACking:IGNore:COUNt? returns the number of

satellites that are on the list to ignore for tracking.

The query :GPS:SATellite:TRACking:INClude:COUNt? returns the number of

satellites that are on the list to be included for tracking.

Response

There may be some delay between changes made to the list of satellites being

ignored and their actual removal and inclusion in the tracking process.

At :SYSTem:PRESet, all satellites are put on the list to include for tracking.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Selecting Satellites______________________________ (continued)

RESPONSE FORMAT

:GPS:SATellite:TRACking:IGNore:STATe? . . .

Returns the ignored status of individual satellites.

0 or 1

:GPS:SATellite:TRACking:INClude:STATe? . . .

Returns the include status of the specified satellite.

0 or 1

The query :GPS:SATellite:TRACking:IGNore:STATe? returns the ignored

status of the specified satellite. A satellite is specified by its pseudorandom

noise code (PRN).

The query :GPS:SATellite:TRACking:INClude:STATe? returns the include

status of the specified satellite. A satellite is specified by its pseudorandom

noise code (PRN).

There may be some delay between changes made to the list of satellites being

ignored and their actual removal and inclusion in the tracking process.

Expanded Syntax

:GPS:SATellite:TRACking:IGNore:STATe? <PRN>

:GPS:SATellite:TRACking:INClude:STATe? <PRN>

Parameter

<PRN> parameter is the pseudorandom noise code of the satellite(s) you want

the Receiver to ignore or include. Each satellite has its own unique PRN.

Response

A value of 0 indicates not on the selected list.

A value of 1 indicates on the selected list.

Context Dependencies

After a :SYSTem:PRESet, all satellites are removed from the list to ignore.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Compensating for Antenna Delay_________________________

:SYSTem:PRESet

:GPS:REFerence:ADELay . . .

Sets the GPS antenna delay value in seconds.

0.0

NON-VOLATILE

This command sets the GPS antenna delay value in seconds. It instructs the

Receiver to output its 1 PPS output pulse earlier in time to compensate for

antenna cable delay.

CAUTION

Using this command while the Receiver is in normal locked operation could

cause the Receiver go into holdover.

Expanded Syntax

:GPS:REFerence:ADELay <numeric_value>

Parameter

Numeric_value range is 0 to 0 .000999999 seconds. The resolution is

1 nanosecond.

Zero cable delay is set for a zero-length antenna cable. Consult a cable data

book for the delay per meter for the particular antenna cable used in order to

compute the total cable delay needed for a particular installation.

See Also

:GPS:REFerence:ADELay?

The tables below list the delay values that you need to use with the

:GPS:REFERENCE:ADELAY <seconds> command for the available cable

assemblies.

Delay Values for the 58518A/519A and 58518AA/519AA RG-213 Antenna

Cables

Cable Option

Length

RG 213 or Belden 8267

Antenna Delay

Value

001

002

005

010

015

030

050

5.0 nanoseconds

10.3 nanoseconds

25.2 nanoseconds

50.5 nanoseconds

75.7 nanoseconds

151.5 nanoseconds

252.5 nanoseconds

2 m

5 m

10 m

15 m

30 m

50 m

The nominal delay value is labeled on the cables. Refer to the Designing Your

GPS Antenna System Configuration Guide for more information.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Compensating for Antenna Delay_____________(continued)

Delay Values for the 58520A/521A and 58520AA/521A LMR 400

Antenna Cables

Cable Option

Length

LMR 400 Antenna Delay Value

001

3.9 nanoseconds

002

2 m

8.0 nanoseconds

005

5 m

19.6 nanoseconds

39.3 nanoseconds

59.0 nanoseconds

118.0 nanoseconds

236.1 nanoseconds

432.9 nanoseconds

010

10 m

15 m

30 m

60 m

110 m

015

030

060

110

The nominal delay value is labeled on the cables. Refer to the Designing Your

GPS Antenna System Configuration Guide for more information.

RESPONSE FORMAT

:GPS:REFerence:ADELay?

Returns the GPS antenna delay value in seconds.

d.dEe

This query returns the GPS antenna delay value in seconds. This is the delay

value set by the system installer (or the factory default). It is not a value

measured by the Receiver.

Response

The time units are seconds.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Monitoring Acquisition ___________________________________

RESPONSE FORMAT

:GPS:REFerence:VALid?

Identifies whether the 1 PPS signal is valid.

0 or 1

This query identifies that the 1 PPS signal has locked to a valid GPS reference

and the 1 PPS signal itself is valid.

Response

A value of 1 indicates signal is valid.

A value of 0 indicates signal is not valid.

RESPONSE FORMAT

:GPS:SATellite:TRACking?

Returns a list of all satellites being tracked.

dd, ...

This query returns a list of all satellites being tracked. Each satellite is

identified by its pseudorandom noise code (PRN).

Response

A comma-separated list of satellite pseudorandom noise codes (<PRN>).

The range of each <PRN> is 1 to 32.

A response of 0 indicates no satellites being tracked.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Monitoring Acquisition _________________________ (continued)

RESPONSE FORMAT

:GPS:SATellite:VISible:PREDicted?

Returns the list of satellites (PRN) that the almanac predicts

should be visible, given date, time, and location.

dd, ...

This query returns the list of satellites (PRN) that the almanac predicts should

be visible, given date, time, and location (if any of these values are incorrect,

the prediction will be incorrect). Each satellite is identified by its

pseudorandom noise code (PRN).

Response

A comma-separated list of satellite pseudorandom noise codes (<PRN>).

The range of each <PRN> is 1 to 32.

A response of 0 indicates no satellites predicted visible.

Theory

Satellites must be in view to be tracked. At least four satellites must be in view,

and tracked, to determine the position in position survey operation. Only one

satellite must be in view, and tracked, to maintain operation of the reference

oscillator locked to GPS when in position hold operation.

RESPONSE FORMAT

:GPS:SATellite:TRACking:COUNt?

Returns the number of satellites being tracked.

This query returns the number of satellites being tracked.

Response

If there are no satellites being tracked, this query returns a 0.

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Chapter 5 Command Reference

GPS Satellite Acquisition

Monitoring Acquisition _________________________ (continued)

RESPONSE FORMAT

:GPS:SATellite:VISible:PREDicted:COUNt?

Returns the number of satellites that the almanac predicts should

be visible, given date, time, and location.

This query returns the number of satellites that the almanac predicts should

be visible, given date, time, and location (if any of these are incorrect, the

prediction will be incorrect).

Response

Number of satellites predicted visible.

Theory

Satellites must be in view to be tracked. At least four satellites must be in view,

and tracked, to determine the position in position survey operation. Only one

satellite must be in view, and tracked, to maintain operation of the reference

oscillator locked to GPS when in position hold operation.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

1 PPS and 10 MHz (58503B only) output signals are generated by the

Receiver’s internal reference oscillator. This oscillator is synchronized

(phased locked) to GPS while a sufficient number of satellites are tracked.

When the GPS signal is interrupted or absent, the Receiver maintains timing

and frequency accuracy through its oscillator “holdover” process. While in

holdover, the frequency of the reference oscillator is adjusted as necessary to

compensate for aging characteristics. The Receiver returns to “locked”

operation through a “holdover recovery” process.

The following commands are provided to monitor the operating mode of the

reference oscillator, to determine the accuracy and stability of the reference

output signal(s), and to control the oscillator holdover process.

! Monitoring 1 PPS Synchronization

:SYNChronization:STATe?

:DIAGnostic:ROSCillator:EFControl:RELative?

:LED:GPSLock?

:LED:HOLDover?

! Assessing 1 PPS Quality

:SYNChronization:FFOMerit?

:SYNChronization:HOLDover:TUNCertainty:PREDicted?

:SYNChronization:HOLDover:TUNCertainty:PRESent?

:SYNChronization:TFOMerit?

:SYNChronization:TINTerval?

:SYNChronization:HOLDover:DURation?

:SYNChronization:HOLDover:DURation:THReshold ...

:SYNChronization:HOLDover:DURation:THReshold?

:SYNChronization:HOLDover:DURation:THReshold:EXCeeded?

! Operating in Holdover

" Initiating Manual Holdover

:SYNChronization:HOLDover:INITiate

" Recovering from Holdover

:SYNChronization:HOLDover:WAITing?

:SYNChronization:HOLDover:RECovery:INITiate

:SYNChronization:HOLDover:RECovery:LIMit:IGNore

:SYNChronization:IMMediate

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Monitoring 1 PPS Synchronization _______________________

RESPONSE FORMAT

:SYNChronization:STATe?

Returns the Receiver state.

XYZ

This query returns the Receiver state.

Response

OFF, or HOLD, or WAIT, or REC, or LOCK, or POW.

OFF indicates in diagnostic mode or a temporary start-up mode; HOLD

indicates in manual holdover; WAIT indicates waiting for external conditions

to allow recovery from holdover; REC indicates actively recovering from

holdover; LOCK indicates locked to GPS; POW indicates in powerup prior to

first lock.

Context Dependencies

:SYSTem:PRESet sets the state to POWerup.

RESPONSE FORMAT

:DIAGnostic:ROSCillator:EFControl:RELative?

Returns the Electronic Frequency Control (EFC) output value of

the internal reference oscillator.

d.dEe

This query returns the Electronic Frequency Control (EFC) output value of the

internal reference oscillator. It returns a percentage value.

Response

Range is -100% to +100%.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Monitoring 1 PPS Synchronization _____________ (continued)

RESPONSE FORMAT

:LED:GPSLock?

Returns the state of the front-panel GPS Lock LED.

0 or 1

This query returns the state of the front-panel GPS Lock LED. The Receiver

sets this indicator during normal operation when it has locked the internal

reference oscillator and 1 PPS output to GPS.

Response

A value of 0 indicates the LED is off.

A value of 1 indicates the LED is on.

RESPONSE FORMAT

:LED:HOLDover?

Returns the state of the front–panel Holdover LED.

0 or 1

This query returns the state of the front-panel Holdover LED. The Receiver

sets this indicator when in holdover operation.

Response

A value of 0 indicates the LED is off.

A value of 1 indicates the LED is on.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Assessing 1 PPS Quality__________________________________

RESPONSE FORMAT

:SYNChronization:FFOMerit?

Returns the Frequency Figure of Merit.

This query returns the Frequency Figure of Merit (FFOM). Use this query

when you want to know the stability of the Receiver’s 10 MHz output.

The 10 MHz output is controlled by the SmartClock’s Phase-Locked Loop

(PLL). Thus, the FFOM value is determined by monitoring the status of

the PLL.

Response

The following table lists and defines the FFOM values (0 thru 3) that could be

returned.

FFOM Value Definition

PLL stabilized—10 MHz output within specification.

PLL stabilizing

PLL unlocked (holdover)—Initially the 10 MHz output will be

within specifications. However, when in holdover, the 10 MHz

output will eventually drift out of specification.

PLL unlocked (not in holdover)—Do not use the output.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

RESPONSE FORMAT

:SYNChronization:HOLDover:TUNCertainty:PREDicted?

Returns an estimate of the time interval error that can be expected

for a one day holdover, given the current state of SmartClock

learning in the Receiver.

d.dEe, 0 or 1

This query returns an estimate of the time interval error that can be expected

for a one day holdover, given the current state of SmartClock learning in the

Receiver.

Response

The first number in the response is the estimated time interval error. The units

are seconds, the resolution is 100 nanoseconds.

The second number in the response identifies the holdover state. A value of 0

indicates the Receiver is not in holdover; a value of 1 indicates the Receiver is

in holdover.

Context Dependencies

This query is not valid prior to first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet. Sending this query before first

lock will generate error -230.

RESPONSE FORMAT

:SYNChronization:HOLDover:TUNCertainty:PRESent?

Returns the current time interval error during holdover operation,

given the current state of SmartClock learning in the Receiver.

d.dEe

This query returns the current time error during holdover operation, given the

current state of SmartClock learning in the Receiver.

Response

The time error units are seconds.

Context Dependencies

This query is valid when the Receiver is in holdover. If not in holdover,

error -230 is generated.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

RESPONSE FORMAT

:SYNChronization:TFOMerit?

Returns the Time Figure of Merit.

This query returns the Time Figure of Merit. Use this query when you want to

know the accuracy of the Receiver’s 1 PPS output. A low TFOM value indicates

a more accurate output. A value of 3 indicates that the Time Error ranges from

100 to 1000 nanoseconds.

Response

The following table lists the TFOM values that could be returned and provides

the corresponding Time Error.

TFOM Value Time Error

(in nanoseconds)

TFOM Value Time Error

(in nanoseconds)

0^*

less than 1

10 –10

1–10

10 –10

10–100

100–1000

10 –10

greater than 10

* The TFOM values 0, 1, and 2 are not presently used in the 58503B and 59551A products. The

58503B and 59551A products will display TFOM values ranging from 9 to 3, which is consistent with

the specified accuracies of each product

RESPONSE FORMAT

:SYNChronization:TINTerval?

Returns the difference or timing shift between the SmartClock 1

PPS and the GPS 1 PPS signals.

d.dEe

This query returns the difference or timing shift between the SmartClock

1 PPS and the GPS 1 PPS signals. It generates an error when this interval is

unavailable (That is, if no GPS 1 PPS).

Response

Time interval units are seconds.

Resolution is 1E-10 seconds.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

RESPONSE FORMAT

:SYNChronization:HOLDover:DURation?

Returns the duration of the present or most recent period of

operation in the holdover and holdover processes.

d.dEe, 0 or 1

This query returns the duration of the present or most recent period of

operation in the holdover and holdover processes. This is the length of time the

reference oscillator was not locked to GPS. The time units are seconds.

Response

The first number in the response is the holdover duration. The duration units

are seconds, and the resolution is 1 second.

If the Receiver is in holdover, the response quantifies the current holdover

duration. If the Receiver is not in holdover, the response quantifies the

previous holdover.

The second number in the response identifies the holdover state. A value of 0

indicates the Receiver is not in holdover; a value of 1 indicates the Receiver is

in holdover.

Context Dependencies

This query is always valid. If this query is sent before the first holdover has

occurred, the response will be 0,0, indicating that the Receiver is currently not

in holdover and last holdover duration was 0 seconds (user infers there has not

been one yet).

Set to 0,0 after a :SYSTem:PRESet. If there was a prior holdover, the duration

will be lost.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

:SYSTem:PRESet

:SYNChronization:HOLDover:DURation:THReshold . . .

Sets the duration (in seconds) to be used as a limit each time

holdover begins.

86400

(i.e., 1 day)

NON-VOLATILE

This command sets the duration (in seconds) which represents a limit against

which the elapsed time of holdover is compared. If the elapsed time in holdover

(and associated processes) exceeds the limit, a flag is set. The flag indicating

the limit is exceeded can be queried using the

:SYNC:HOLD:DUR:THR:EXCeeded? query.

Expanded Syntax

:SYNChronization:HOLDover:DURation:THReshold <seconds>

Parameter

Resolution of the <seconds> parameter is 1 second.

RESPONSE FORMAT

:SYNChronization:HOLDover:DURation:THReshold?

Returns the duration (in seconds) which represents a limit against

which the elapsed time of holdover is compared.

This query returns the duration (in seconds) which represents a limit against

which the elapsed time of holdover is compared. If the elapsed time of holdover

(and associated processes) exceeds the limit, a flag is set.

Expanded Syntax

:SYNChronization:HOLDover:DURation:THReshold?

Response

The threshold units are seconds.

The resolution is 1 second

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

RESPONSE FORMAT

:SYNChronization:HOLDover:DURation:THReshold

:EXCeeded?

Identifies if the Receiver has been in holdover longer than the

amount of time specified by the THReshold command.

0 or 1

This query identifies if the Receiver has been in holdover longer than the

amount of time specified by the THReshold command. If it has, 1 will be

returned.

Response

A value of 1 indicates that the Receiver is in holdover, and has been operating

in holdover for a duration that exceeds the specified duration.

The value 0 indicates either the Receiver is not in holdover, or it has been in

holdover for less than the specified duration.

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Operating in Holdover ____________________________________

" Initiating Manual Holdover __________________________________

:SYNChronization:HOLDover:INITiate

Places the Receiver in holdover mode.

EVENT

This command places the Receiver in holdover mode. The Receiver will stay in

holdover until you send :SYNC:HOLD:REC:INIT.

Context Dependencies

This command is not valid prior to the first lock following powerup (see bit 2 of

the Powerup Status Register) or :SYSTem:PRESet. Sending this command

before the first lock will generate error -221.

See Also

:SYNChronization:HOLDover:RECovery:INITiate

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Operating in Holdover __________________________ (continued)

" Recovering from Holdover _________________________________

RESPONSE FORMAT

:SYNChronization:HOLDover:WAITing?

Returns prioritized reason for why the Receiver is waiting to

recover.

XYZ

This query returns prioritized reason for why the Receiver is waiting to

recover.

Response

HARD indicates there is an internal hardware reason, GPS indicates there are

no satellites, LIM indicates the time interval between GPS and internal

oscillator is exceeding the limit, and NONE indicates the Receiver isn’t waiting

to recover.

Note that if holdover has been initiated by sending the :SYNC:HOLD:INIT

command, the Receiver is not waiting to recover; the response is NONE.

This query is always valid. If not in holdover and waiting to recover, NONE will

be the response.

:SYNChronization:HOLDover:RECovery:INITiate

Initiates a recovery from manually initiated holdover.

EVENT

This command initiates a recovery from manually initiated holdover. Use this

command to take the Receiver out of a manually selected holdover. This

command is not needed to initiate holdover recovery in any other situation.

See Also

:SYNChronization:HOLDover:INITiate

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Chapter 5 Command Reference

1 PPS Reference Synchronization

Operating in Holdover __________________________ (continued)

" Recovering from Holdover (continued)

:SYNChronization:HOLDover:RECovery:LIMit:IGNore

Initiates recovery from holdover if recovery was inhibited by time

intervals exceeding limit.

EVENT

This command initiates recovery from holdover if recovery was inhibited by

time intervals exceeding limit.

The time interval used for this comparison is the time interval between the

internal oscillator’s 1 PPS edge and the GPS system’s 1 PPS edge. When this

time interval consistently exceeds the specified limit, the instrument enters

the holdover state, “Waiting to Recover.”

Recovery is initiated when the time intervals consistently fall within limits,

or when the limit is ignored by issuing this command.

:SYNChronization:IMMediate

Initiates a near-instantaneous alignment of the GPS 1 PPS and

Receiver output 1 PPS if the command is issued during recovery

from holdover.

EVENT

This command initiates a near-instantaneous alignment of the GPS 1 PPS and

Receiver output 1 PPS if the command is issued during recovery from holdover.

Context Dependencies

This command is only valid when recovering from holdover. See bit 2 of the

Holdover Status Register (if it is 1, this command is okay). Sending this

command when the Receiver is not recovering will generate error -221.

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Chapter 5 Command Reference

Operating Status

This section describes the commands that can be use to obtain Receiver status

information. There are several ways to obtain Receiver status using

commands. For example, you can send a command to display the Receiver

Status screen, to read the error queue, and to read the diagnostic log. You can

also send a sequence of commands to read and control the status registers for

alarm generation.

This section defines all of the commands used for status reporting.

A comprehensive discussion on how you can monitor and control alarm

conditions using the status registers is included.

! Receiver Operation at a Glance

:SYSTem:STATus?

:SYSTem:STATus:LENGth?

! Reading the Error Queue

:SYSTem:ERRor?

! Reading the Diagnostic Log

:DIAGnostic:LOG:CLEar

:DIAGnostic:LOG:READ:ALL?

:DIAGnostic:LOG:CLEar ...

:DIAGnostic:LOG:COUNt?

:DIAGnostic:LOG:READ?

:DIAGnostic:LOG:READ? ...

! Monitoring Status/Alarm Conditions

" Clearing and Presetting Alarms

*CLS

:STATus:PRESet:ALARm

" Reading and Qualifying Alarms

:LED:ALARm?

*SRE ...

*SRE?

*STB?

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Chapter 5 Command Reference

Operating Status

" Reading and Qualifying Receiver Status

<register> = OPERation

<register> = QUEStionable

<register> = OPERation:HARDware

<register> = OPERation:HOLDover

<register> = OPERation:POWerup

:STATus:<register>:CONDition?

:STATus:<register>:EVENt?

:STATus:<register>:ENABle ...

:STATus:<register>:ENABle?

:STATus:<register>:NTRansition ...

:STATus:<register>:NTRansition?

:STATus:<register>:PTRansition ...

:STATus:<register>:PTRansition?

" Reading and Qualifying Command Error Status

*ESE ...

*ESE?

*ESR?

" Reporting Questionable Status

:STATus:QUEStionable:CONDition:USER ...

:STATus:QUEStionable:EVENt:USER ...

! Assessing Receiver Health

*TST?

:DIAGnostic:LIFetime:COUNt?

:DIAGnostic:TEST? ...

:DIAGnostic:TEST:RESult?

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Chapter 5 Command Reference

Operating Status

Receiver Operation at a Glance ___________________________

RESPONSE FORMAT

:SYSTem:STATus?

Outputs a formatted status screen.

ASCII Data

This query outputs a formatted Receiver Status screen. Use this screen to

monitor GPS acquisition, derivation of time and position, and synchronization

of reference outputs to GPS.

Refer to Chapter 3, “Visual User Interface,” for detailed information on the

Receiver Status screen.

Response

Sending this command will display a status screen similar to the following

figure (58503B screen is shown in this figure).

Receiver Status

----------------------------

SYNCHRONIZATION..........................................

----------------------------

]

[

Reference Outputs

Outputs Valid

SmartClock Mode

Locked to GPS

TFOM

FFOM

Recovery

Holdover

Power-up

1PPS TI +7.2 ns relative to GPS

HOLD THR 1.000 us

Holdover Uncertainty

Predict 49.0 us/initial 24 hrs

................................................[GPS 1PPS Valid]

Not Tracking: 1

ACQUISITION

Tracking: 6

PRN El Az C/N PRN El Az

Time

UTC

+1 leap second pending

23:59:59 31 Dec 1995

2 49 243 49

16 24 282 44

18 38 154 49

19 65 52 43

27 62 327 44

31 34 61 38

14 11 82

GPS 1PPS Synchronized to UTC

ANT DLY 120 ns

Position

MODE

Survey: 17.5% complete

AVG LAT N 37:19:32.264

AVG LON W 121:59:52.112

AVG HGT

......................................................

+41.86 m (GPS)

[ OK ]

ELEV MASK 10 deg

HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK

OCXO: OK EFC: OK GPS Rcv: OK

RESPONSE FORMAT

:SYSTem:STATus:LENGth?

Returns the number of lines of formatted text that are in the

Receiver Status screen.

This query returns the number of lines of formatted text that are in the

Receiver Status screen.

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Chapter 5 Command Reference

Operating Status

Reading the Error Queue _________________________________

RESPONSE FORMAT

:SYSTem:ERRor?

Returns the oldest error in the Error Queue and removes that error

from the queue (first in, first out).

dd,“XYZ”

This query returns the oldest error in the Error Queue and removes that error

from the queue (first in, first out).

See Appendix A, “Error Messages,” in this guide for detailed error information.

Response

The error response format is: <error_number>, “<error_description>”, where

•

The <error_number> is an integer transferred as ASCII bytes in

<NR1>format (integer). The range is -32768 to 32767.

•

Negative error numbers are defined by the SCPI standard.

Positive error numbers are defined specifically for this Receiver.

An error number value of zero indicates that the Error Queue is empty.

The maximum length of the <error_description> is 255 characters.

Context Dependencies

:SYSTem:PRESet clears the Error Queue.

The queue is cleared (emptied) on *CLS, power-on, or upon reading the last

error from the queue.

If the Error Queue overflows, the last error in the queue is replaced with the

error -350, "Queue overflow". Any time the queue overflows, the least recent

errors remain in the queue and the most recent error is discarded.

The maximum length of the Error Queue is 30.

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Chapter 5 Command Reference

Operating Status

Reading the Diagnostic Log ______________________________

The Diagnostic Log is one way to obtain Receiver status.

The following activities and events are recorded in the diagnostic log:

•

power-on sequence,

automatic or manual transitions between locked, and holdover,

automatic or manual transitions between position survey and position

hold operation,

•

alarm indications, and

self-test failures.

Each entry is date-and-time tagged. The log entries are stored in non-volatile

memory so all data remains valid even if power is lost. Access to the diagnostic

log entries is through commands in the :DIAGnostic:LOG subtree.

For example, to read the first diagnostic log entry, use the command

:DIAG:LOG:READ? 1

The possible log messages that can be displayed on your computer display are

listed in the following table.

Table 5-1. Diagnostic Log Messages

Log Message

Comments

Log cleared

Always becomes first log message when the log is cleared.

See :DIAG:LOG:CLEAR.

Power on

Indicates Receiver has been powered on.

Indicates Receiver processor has re-booted.

Indicates beginning of survey for position.

Indicates transition from survey to position hold.

Indicates transition into locked operation.

Re-boot

Survey mode started

Position hold mode started

GPS lock started

GPS reference valid at

yyyymmdd.hh:mm:ss

Indicates when GPS reference first become valid. Time in log is the present

time from GPS.

Holdover started, manual

Indicates transition to holdover based on user request. See

:SYNC:HOLD:INIT.

Holdover started, TI error

Indicates transition to holdover due to problem detected with Receiver

ability to properly measure interval between GPS 1 PPS and internal

oscillator 1 PPS.

Holdover started, TI limit exceeded

Holdover started, not tracking GPS

Indicates transition to holdover due to the interval from GPS 1 PPS to

internal oscillator 1 PPS exceeding a limit threshold for numerous

measurements.

Indicates transition to holdover since GPS is not tracking sufficient

satellites.

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Chapter 5 Command Reference

Operating Status

Reading the Diagnostic Log ____________________ (continued)

Table 5-1. Diagnostic Log Messages (Continued)

Log Message

Comments

Holdover started, GPS RAIM alarm

Indicates transition to holdover since time RAIM algorithm has detected

GPS 1PPS timing inaccuracy.

Holdover started, GPS Alarm

Holdover started, invalid GPS 1 PPS

Holdover started, GPS

Indicates transition to holdover due to GPS engine communication failure.

Indicates transition to holdover due to problem with the GPS 1 PPS signal.

Indicates transition to holdover due to some other GPS problem.

Indicates transition to holdover due to internal hardware error.

Holdover started, HW error

Holdover started, temporary

Indicates temporary transition to holdover due to changing of certain

settings.

Holdover started

Self-test failed

System preset

Hardware failure

Indicates transition to holdover for any reason not covered above.

Indicates self-test failed on powerup.

Indicates that the Receiver has been preset to factory settings.

Indicates that a hardware failure has been detected. See Hardware Status

EEPROM save failed

Indicates that an attempt to save information to the EEPROM has failed.

The DIAGnostic commands for the log are described in the following text.

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Chapter 5 Command Reference

Operating Status

Reading the Diagnostic Log _____________________

(continued)

:SYSTem:PRESet

:DIAGnostic:LOG:CLEar

Clears the diagnostic log.

Log is cleared

NON-VOLATILE

This command is an event that removes all previous diagnostic log entries, and

effectively sets the number of diagnostic log entries to one.

RESPONSE FORMAT

:DIAGnostic:LOG:READ:ALL?

Returns all of the most recent diagnostic log entries.

“XYZ”, ...

This query returns all of the most recent diagnostic log entries.

:SYSTem:PRESet

Log is cleared

:DIAGnostic:LOG:CLEar . . .

Clears only the current diagnostic log.

NON-VOLATILE

This command clears the diagnostic log. The optional log count parameter is

provided to ensure that no log entries are unread at the time of the clear.

Expanded Syntax

:DIAGnostic:LOG:CLEar <current log size>

Parameter

If the value sent for the optional log parameter does not match the current log

entry count (use :DIAG:LOG:COUN? to obtain this number), the clear will not

take place.

Context Dependencies

This command is always valid. If the optional log count parameter is sent, and

the current and actual log count does not match log count value, the clear will

not be performed and error -222 will be generated.

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Chapter 5 Command Reference

Operating Status

Reading the Diagnostic Log _____________________

(continued)

RESPONSE FORMAT

:DIAGnostic:LOG:COUNt?

Identifies the number of entries in the diagnostic log.

This query identifies the number of entries in the diagnostic log.

Response

Range is 1 to 222, maximum is subject to change.

RESPONSE FORMAT

:DIAGnostic:LOG:READ?

Returns the most recent diagnostic log entry.

“XYZ”

This query returns the most recent diagnostic log entry.

Response

The diagnostic log entry format is: “Log NNN: YYYYMMDD.HH:MM:SS:

<log_message>”, where:

Log indicates a diagnostic log entry, and NNN is the log entry number

YYYYMMDD.HH:MM:SS is the date and time of the diagnostic log entry.

The <log_message> is a sequence of up to 255 characters.

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Chapter 5 Command Reference

Operating Status

Reading the Diagnostic Log _____________________

(continued)

RESPONSE FORMAT

“XYZ”

:DIAGnostic:LOG:READ? . . .

Returns the user-specified diagnostic log entry. Returns the most

recent diagnostic log entry if no parameter is supplied.

This query returns the user-specified diagnostic log entry.

Expanded Syntax

:DIAGnostic:LOG:READ? <entry number>

Parameter

Range is 1 to current log count.

Response

The diagnostic log entry format is: “Log NNN: YYYYMMDD.HH:MM:SS:

<log_message>”, where:

Log indicates a diagnostic log entry, and NNN is the log entry number

YYYYMMDD.HH:MM:SS is the date and time of the diagnostic log entry.

The <log_message> is a sequence of up to 255 characters.

Context Dependencies

This query is always valid. If no log message is associated with the requested

log number, error -222 is generated.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions _____________________

The Receiver is at all times monitoring various operating conditions through a

status/alarm reporting system. The Receiver is shipped from the factory with

the status system set to generate an alarm under a default set of operating

conditions.

The monitored operating conditions are organized by function into three major

groups: Questionable status, Command Error status, and Operation status.

The Operation status group has three functional subgroups: Powerup status,

Holdover status, and Hardware status.

All of the operating conditions are summarized by the Alarm status.

Figure 5-1, on the next page, includes the identification of the default alarm

conditions. Those conditions which are enabled to “feed” all the way through

the system will generate an alarm in a Receiver configured with the factory

defaults. (Note a diagram identical to Figure 5-1 is provides as part of the

Receiver Commands at a Glance (cont’d)/Status Reporting System at a Glance

foldout—pages 4-17 and 4-18, respectively.)

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

Questionable

Binary Weights

"OR"

Time Reset

User-reported

256

512

10 1024

11 2048

12 4096

13 8192

14 16384

15 32768

Alarm

128

not used

Command Error

not used

"OR"

not used

Questionable Summary

not used

Query Error

Hardware/Firmware Error

Semantic Error

Syntactic Error

not used

"OR"

Alarm

Command Error Summary

Master Summary

Operation Summary

Power Cycled

Powerup

First Satellite Tracked

Oscillator Oven Warm

Date & Time Valid

Operation

Powerup Summary

Locked

Holdover Summary

Position Hold

1 PPS Reference Valid

Hardware Summary

Log Almost Full

"OR"

Holdover

Holding

Waiting to Recover

Recovering

Exceeding Threshold

Hardware

Selftest Failure

+15V Supply Exceeds Tolerance

-15V Supply Exceeds Tolerance

+5V Supply Exceeds Tolerance

Oven Supply Exceeds Tolerance

not used

"OR"

Shading identifies

summary bit.

EFC Voltage Near Full-Scale

EFC Voltage Full-Scale

GPS 1 PPS Failure

Powerup Summary

Default Transition Filter

Default Event Enable

GPS Failure

False-to-true (positive)

transition latches event.

Event enabled to report to

summary bit.

TI Measurement Failed

EEPROM Write Failed

Internal Reference Failure

Not applicable

Event disabled

Figure 5-1. 59551A/58503B Status Reporting System Diagram

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

The following describes, for each functional group of operating status shown in

Figure 5-1, each of the operating conditions that is monitored through the

status/alarm system.

Each monitored condition bit is “set” (to one) when the named condition is true

and “cleared” (to zero) when the named condition is false.

Each monitored event bit is set when the named event has occurred and

cleared at powerup and when the user executes a command which reads or

clears the event register.

All of the conditions and events are cleared at powerup and :SYSTem:PRESet.

Alarm Status

The Alarm Status summarizes condition changes from the three major

functional status groups (Questionable, Command Error, and Operation).

•

The Questionable Summary condition (bit 3) reflects one or more latched

condition changes in the Questionable status group.

The Command Error Summary condition (bit 5) reflects one or more

latched condition changes in the Command Error status group.

The Master Summary condition (bit 6) indicates that there was at least

one reason for generating an Alarm.

The Operation Summary condition (bit 7) reflects one or more latched

condition changes in the Operation status group.

Operation Status

The Operation Status is comprised of the Operation subgroup (Powerup,

Holdover, and Hardware) summaries, Locked, Position Hold, 1 PPS Reference

Valid, and Log Almost Full status.

•

The Powerup Summary condition (bit 0) reflects one or more latched

condition changes in the Powerup status group.

The Locked condition (bit 1) indicates whether or not the Receiver is

locked to GPS.

The Holdover Summary condition (bit 2) reflects one or more latched

condition changes in the Holdover status group.

The Position Hold condition (bit 3) indicates whether the Receiver is in

position hold or survey mode.

The 1 PPS Reference Valid condition (bit 4) indicates that the GPS 1 PPS

signal is suitable to use as a locking reference.

The Hardware Summary condition (bit 5) reflects one or more latched

condition changes in the Hardware status group.

The Log Almost Full condition (bit 6) indicates whether or not the

diagnostic log is approaching the point where new entries will no longer be

logged.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

Hardware Status

This Operation subgroup comprises operating status that indicates the health

of the Receiver hardware.

One or more of the condition changes from this group are summarized in the

Operation Status group.

•

The Selftest Failure condition (bit 0) indicates whether a failure was

detected during the powerup or last user-initiated self-test.

•

The following conditions reflect the status of specific hardware that is

continuously monitored by the Receiver:

(bit 1)

(bit 2)

(bit 3)

(bit 4)

(bit 6)

(bit 7)

(bit 8)

(bit 9)

(bit 10)

(bit 12)

+15V Supply Exceeds Tolerance condition

−15V Supply Exceeds Tolerance condition

+5V Supply Exceeds Tolerance condition

Oven Supply Exceeds Tolerance condition

EFC Voltage Near Full-Scale condition

EFC Voltage Full-Scale condition

GPS 1 PPS Failure condition

GPS Failure condition

Time Interval Measurement Failed event

Internal Reference Failure condition

•

The EEPROM Write Failed event (bit 11) indicates that an attempt to

write to the non-volatile memory failed.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

Holdover Status

This Operation subgroup is comprised of operating status that occurs during

holdover.

One or more of the condition changes from this group are summarized in the

Operation Status group.

•

The following conditions indicate that the Receiver is in holdover, and the

specific holdover state:

(bit 0)

(bit 1)

(bit 2)

Holding condition

Waiting to Recover condition

Recovering condition

•

The Exceeding User-Threshold condition (bit 3) indicates whether or not

the user-specified holdover duration

(:SYNC:HOLDover:DURation:THReshold) is being exceeded.

Powerup Status

This Operation subgroup is comprised of operating status that occurs at

powerup.

One or more of the condition changes from this group are summarized in the

Operation Status group.

•

The First Satellite Tracked condition (bit 0) is cleared at powerup and set

when the first satellite becomes tracked following powerup.

The Oscillator Oven Warm condition (bit 1) is cleared at powerup and set

when the internal oscillator has warmed up following powerup.

The Date & Time Valid event (bit 2) is cleared at powerup and set when

the date and time are set during the first lock is attained after powerup.

Questionable Status

The Time Reset status event (bit 0) indicates that the Receiver reset its time

because the Receiver's time was found to be different from the time being

reported by the satellites. This could occur after an extensive holdover period.

The User-reported condition (bit 1) indicates the setting reported by the user

with the :STATus:QUEStionable:CONDition:USER or

:STATus:QUEStionable:EVENt:USER command. This is the only condition in

the status/alarm reporting that the user can directly affect.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

Command Error Status

This group contains events which indicate a command error has occurred, and

an event which indicates that the power has cycled. (See Figure 5-1.)

The following status events indicate that a command error occurred:

•

The Query Error status event (bit 2). Errors -400 through -499 are query

errors.

The Hardware/Firmware Error status event (bit 3). Errors -300 through

-399 are hardware/firmware errors.

The Semantic Error status event (bit 4). Errors -200 through -299 are

semantic errors.

The Syntactic Error status event (bit 5). Errors -100 through -199 are

syntactic errors.

The Power Cycled status event (bit 7) is set at powerup.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Clearing and Presetting Alarms ______________________________

*CLS

Clears the current alarm and prepares the Receiver for the next

alarm activation.

EVENT

When the *CLS command clears the event status registers and error queue, the

Receiver’s Alarm LED and Alarm BITE output will no longer indicate that

there was a reason to alarm. Furthermore, the Receiver is then ready to detect

a new alarm.

Context Dependencies

In the 59551A, the error queue (and corresponding serial port prompt) of the

I/O port which transmitted *CLS will be cleared.

Side Effects

The Alarm LED is extinguished.

The Alarm BITE output is set “inactive/off.”

The prompt of the serial I/O port (which transmits *CLS) reflects error queue

clearing.

The event status registers are cleared.

The error queue (and corresponding serial port prompt) of the I/O port which

transmitted *CLS will be cleared.

Theory

The *CLS command clears the event status registers and error queue.

(They are also cleared at power-up.)

Since the Alarm Condition register summarizes the event registers, it is

cleared as a result of the clearing of all of the event registers.

The alarm remains active even after the condition that caused it has gone

away.

If the condition that caused the alarm to occur is still set, a new alarm cannot

be detected until the condition clears and resets.

This command has no effect on condition, enable, or transition filter registers.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Clearing and Presetting Alarms (continued)

:STATus:PRESet:ALARm

Presets the status/alarm reporting system to generate an alarm

when a factory default set of operating conditions occurs.

EVENT

When the configurable portion of the status/alarm reporting system is preset,

the Receiver is configured to generate an alarm under the factory default set of

operating conditions.

Use this command to restore only the status/alarm reporting system to the

factory (:SYSTem:PRESet) settings.

Theory

The configurable portion of the status/alarm reporting system consists of

enable and transition filter registers. Figure 5-1 identifies the factory default

enables and transitions.

The status/alarm reporting configuration is stored in non-volatile memory.

This command performs a subset of the :SYSTem:PRESet command in that it

only presets the configuration associated with status/alarm reporting system.

This command does not affect condition or event registers.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Alarms _____________________________

Alarm

Condition

not used

Questionable Summary

not used

STB?

Command Error Summary

Master Summary

"AND"

Operation Summary

Alarm

Enable

"OR"

:LED:ALARm?

Alarm

not used

Questionable Summary

not used

SRE <bit mask>

SRE?

Command Error Summary

not used

Operation Summary

Figure 5-2. Alarm Condition and Enable Registers

RESPONSE FORMAT

:LED:ALARm?

Returns the status of the front-panel Alarm LED.

0 or 1

This query returns the status of the front-panel Alarm LED, which indicates

that a change in operating conditions was recorded. The alarm remains active

even after the condition that caused it has gone away.

Theory

This query essentially reads the Master Summary bit (bit 6) of the Alarm

Condition Register.

At power-up, the alarm status is cleared.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Alarms (continued)

:SYSTem:PRESet

*SRE . . .

Sets the Alarm Enable Register.

136

NON-VOLATILE

The setting of the Alarm Enable Register (Figure 5-2) selects which summary

status from the Alarm Condition Register is enabled to generate an alarm.

Expanded Syntax

*SRE <bit mask>

Semantics

The <bit mask> has a range of 0 to 255.

The <bit mask> value represents the sum of the binary-weighted values of the

unused bits is zero.

RESPONSE FORMAT

*SRE?

Identifies the status conditions enabled to generate an alarm.

This query identifies the status conditions enabled to generate an alarm.

Reading the Alarm Enable Register identifies which summary status from the

Alarm Condition Register is enabled to generate an alarm.

Response

The range is 0 to 255.

The response value represents the sum of the binary-weighted values of the

Theory

Reading/Querying the Alarm Enable Register does not change its contents.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Alarms (continued)

RESPONSE FORMAT

*STB?

Reads the Alarm Condition Register.

This query reads the Alarm Condition Register (Figure 5-2).

Response

The range is 0 to 255.

The response value represents the sum of the binary-weighted values of the

Theory

The Alarm Condition Register continuously monitors the summary status of

the instrument.

The Alarm Condition Register bits are updated in real time—there is no

latching or buffering.

Reading/Querying the Alarm Condition Register does not change its contents.

At powerup, the Alarm Condition Register is cleared.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status ____________________

Condition

Transition

Filter

Event

"AND"

"OR"

Summary

Bit

Enables condition changes to

report to Event Register

:STATus:<register>:PTR . . .

:STATus:<register>:PTR?

:STATus:<register>:NTR . . .

:STATus:<register>:NTR?

Latches condition changes

:STATus:<register>:EVENt?

Continuously monitors

conditions

:STATus:<register>:CONDition?

Event

Enable

positive transition or

negative transition or

either transition or

neither transition

<register> = OPERation or

QUEStionable or

Enables events to

report to summary bit

OPERation:HARDware or

:STATus:<register>:ENABle <bit mask>

:STATus:<register>:ENABle?

OPERation:HOLDover or

OPERation:POWerup

Figure 5-3. Condition, Transition Filter, Event Enable, and Event

Registers

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status (continued)

RESPONSE FORMAT

:STATus:<register>:CONDition?

Reads the specified condition register.

This query reads the specified condition register (figures 5-3 and 5-1).

Expanded Syntax

:STATus:OPERation:CONDition?

:STATus:QUEStionable:CONDition?

:STATus:OPERation:HARDware:CONDition?

:STATus:OPERation:HOLDover:CONDition?

:STATus:OPERation:POWerup:CONDition?

Response

The range is 0 to 65535.

The response value represents the sum of the binary-weighted values of the

Note that some bits, those which are “event-only”, have no corresponding

conditions.

Theory

A condition register continuously monitors the hardware and firmware status

(that is, the operating conditions) of the instrument.

Conditions register bits are updated in real time—there is no latching or

buffering.

Reading/Querying a condition register does not change its contents.

At powerup, the conditions registers are cleared.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status (continued)

RESPONSE FORMAT

:STATus:<register>:EVENt?

Reads the specified event register.

This query reads the specified event register (figures 5-3 and 5-1), retrieving

information about what has happened to the instrument since it was last

queried, or cleared by :SYSTem:PRESet or *CLS.

Expanded Syntax

:STATus:OPERation:EVENt?

:STATus:QUEStionable:EVENt?

:STATus:OPERation:HARDware:EVENt?

:STATus:OPERation:HOLDover:EVENt?

:STATus:OPERation:POWerup:EVENt?

Response

The range is 0 to 65535.

The response value represents the sum of the binary-weighted values of the

Side Effects

Reading/Querying an event register clears it.

Theory

An event register captures changes in conditions. When a transition occurs, the

corresponding bit in the event register is set TRUE. The instrument can be

configured (using :STATus:<register>:NTRansition and

:STATus:<register>:PTRansition), for each bit position, to capture the positive,

the negative, either, or neither transition.

Event register bits, once set, are latched. That is, they remain set until they are

read. When they are read, they are cleared.

At powerup, the event registers are cleared.

See Also

:STATus:<register>:NTRansition . . .

:STATus:<register>:PTRansition . . .

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status (continued)

:SYSTem:PRESet

:STATus:<register>:ENABle . . .

Sets the specified enable register.

See Figure 5-1 for Default

Event Enable identification

NON-VOLATILE

The setting of an enable register (figures 5-3 and 5-1) selects which events from

the corresponding event register are enabled to report to the corresponding

summary bit of the summarizing condition register.

Expanded Syntax

:STATus:OPERation:ENABle <bit mask>

:STATus:QUEStionable:ENABle <bit mask>

:STATus:OPERation:HARDware:ENABle <bit mask>

:STATus:OPERation:HOLDover:ENABle <bit mask>

:STATus:OPERation:POWerup:ENABle <bit mask>

Parameter

The <bit mask> has a range of 0 to 65535.

The <bit mask> value represents the sum of the binary-weighted values of the

value of unused bits is zero.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status (continued)

RESPONSE FORMAT

:STATus:<register>:ENABle?

Reads the specified enable register.

Reading an enable register (figures 5-3 and 5-1) identifies which events from

the corresponding event register are enabled to report to the corresponding

summary bit of the summarizing condition register.

Expanded Syntax

:STATus:OPERation:ENABle?

:STATus:QUEStionable:ENABle?

:STATus:OPERation:HARDware:ENABle?

:STATus:OPERation:HOLDover:ENABle?

:STATus:OPERation:POWerup:ENABle?

Response

The range is 0 to 65535.

The response value represents the sum of the binary-weighted values of the

Theory

Reading/Querying an enable register does not change its contents.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status (continued)

:SYSTem:PRESet

:STATus:<register>:NTRansition . . .

:STATus:<register>:PTRansition . . .

Sets the specified transition filter registers.

See Figure 5-1 for Default

Transition Filter

identification

NON-VOLATILE

The setting of the transition filter registers selects which condition transitions

(positive, negative, either, or neither) are enabled to report events.

Expanded Syntax

:STATus:OPERation:NTRansition <bit mask>

:STATus:QUEStionable:NTRansition <bit mask>

:STATus:OPERation:HARDware:NTRansition <bit mask>

:STATus:OPERation:HOLDover:NTRansition <bit mask>

:STATus:OPERation:POWerup:NTRansition <bit mask>

:STATus:OPERation:PTRansition <bit mask>

:STATus:QUEStionable:PTRansition <bit mask>

:STATus:OPERation:HARDware:PTRansition <bit mask>

:STATus:OPERation:HOLDover:PTRansition <bit mask>

:STATus:OPERation:POWerup:PTRansition <bit mask>

Parameter

The <bit mask> has a range of 0 to 65535.

The <bit mask> value represents the sum of the binary-weighted values of the

value of unused bits is zero.

To enable negative (one to zero) transitions of specific conditions, set the

corresponding bits to one in the <bit mask> for the NTRansition register

command.

To enable positive (zero to one) transitions of specific conditions, set the

corresponding bits to one in the <bit mask> for the PTRansition register

command.

Note that some bits, those which are “event-only”, have no transition filter

setting. Attempts to set these bits are ignored.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Receiver Status (continued)

RESPONSE FORMAT

:STATus:<register>:NTRansition?

:STATus:<register>:PTRansition?

Reads the specified transition filter registers.

Reading the transition filter registers identifies which condition transitions

(positive, negative, either, or neither) are enabled to report events.

Expanded Syntax

:STATus:OPERation:NTRansition?

:STATus:QUEStionable:NTRansition?

:STATus:OPERation:HARDware:NTRansition?

:STATus:OPERation:HOLDover:NTRansition?

:STATus:OPERation:POWerup:NTRansition?

:STATus:OPERation:PTRansition?

:STATus:QUEStionable:PTRansition?

:STATus:OPERation:HARDware:PTRansition?

:STATus:OPERation:HOLDover:PTRansition?

:STATus:OPERation:POWerup:PTRansition?

Response

The range is 0 to 65535.

The response value represents the sum of the binary-weighted values of the

The bits which are set to one in the <bit mask> of the NTRansition query

response indicate the enabled negative transitions of corresponding conditions.

The bits which are set to one in the <bit mask> of the PTRansition query

response indicate the enabled positive transitions of corresponding conditions.

Theory

Reading/Querying a transition filter register does not change its contents.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Command Error Status ____________

Command Error

Event

not used

Query Error

"AND"

Hardware/Firmware Error

Semantic Error

Syntactic Error

not used

ESR?

Power Cycled

Command Error

Enable

"OR"

Command Error

Summary Bit of

Alarm Condition

not used

Query Error

Hardware/Firmware Error

Semantic Error

Syntactic Error

not used

ESE <bit mask>

ESE?

Power Cycled

Figure 5-4. Command Error Event and Enable Registers

:SYSTem:PRESet

*ESE . . .

Sets the Command Error Enable Register.

NON-VOLATILE

The setting of the Command Error Enable Register (Figure 5-4) selects which

events from the Command Error Event Register are enabled to report to the

Command Error Summary bit of the Alarm Condition Register.

Expanded Syntax

*ESE <bit mask>

Parameter

The <bit mask> has a range of 0 to 255.

The <bit mask> value represents the sum of the binary-weighted values of the

unused bits is zero.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reading and Qualifying Command Error Status (continued)

RESPONSE FORMAT

*ESE?

Reads the Command Error Enable Register.

This query identifies the status conditions enabled to generate an alarm.

Reading the Command Error Enable Register (Figure 5-4) identifies which

events from the Command Error Event Register are enabled to report to the

Command Error Summary bit of the Alarm Condition Register.

Response

The range is 0 to 255.

The response value represents the sum of the binary–weighted values of the

Theory

Reading/Querying the Command Error Enable Register does not change its

contents.

RESPONSE FORMAT

*ESR?

Reads the Command Error Event Register.

This query reads the Command Error Event Register, retrieving information

about errors (or power cycles) that have occurred since the instrument was last

queried, or cleared by SYSTem:PRESet or *CLS.

Response

The range is 0 to 255.

The response value represents the sum of the binary-weighted values of the

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reporting Questionable Status ____________________________

:SYSTem:PRESet

:STATus:QUEStionable:CONDition:USER . . .

Sets the User-reported bit of the Questionable Condition Register.

Clear

NON-VOLATILE

This command sets the User-reported bit of the Questionable Condition

Expanded Syntax

:STATus:QUEStionable:CONDition:USER SET or CLEar

Parameter

SET will cause the User-reported bit of Questionable Condition Register to be

set to 1.

CLEar will cause the User-reported bit of Questionable Condition Register to

be set to 0.

Side Effects

The User-reported bit of the Questionable Condition Register is set or cleared

by this command.

Theory

A condition change (from SET to CLEAR, or CLEAR to SET) of the User-

reported bit of the Questionable Condition Register, and the appropriate

configuration of the Questionable Transition Filter is necessary to generate an

event in the Questionable Event Register.

Furthermore, when the User-reported bit of Questionable Event Enable

generate an ALARM.

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Chapter 5 Command Reference

Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

! Reporting Questionable Status (continued)

:STATus:QUEStionable:EVENt:USER . . .

Generates a transition of the User-reported bit of the Questionable

Condition Register.

EVENT

NON-VOLATILE

This command generates a transition of the User-reported bit of the

Questionable Condition Register.

Expanded Syntax

:STATus:QUEStionable:EVENt:USER PTRansition or NTRansition

Parameter

PTRansition will cause the User-reported bit of Questionable Condition

NTRansition will cause the User-reported bit of Questionable Condition

Context Dependencies

Issuing PTRansition, while the User-reported bit of the Questionable Positive

Transition Register is enabled, sets the User-reported bit of the Questionable

Event register.

Issuing NTRansition, while the User-reported bit of the Questionable Negative

Transition Register is enabled, sets the User-reported bit of the Questionable

Event register.

Side Effects

The user-reported bit of the Questionable Condition Register is set by the

PTRansition parameter or cleared by the NTRansition parameter.

Theory

A positive or negative (PTRansition or NTRansition) of the User-reported bit of

the Questionable Condition Register, and the appropriate configuration of the

Questionable Transition Filter is necessary to generate an event in the

Questionable Event Register.

Furthermore, when the User-reported bit of Questionable Event Enable

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Chapter 5 Command Reference

Operating Status

Assessing Receiver Health ________________________________

RESPONSE FORMAT

*TST?

Executes an internal selftest and reports the results.

This query causes an internal selftest and the response indicates whether any

errors were detected. This test takes about 40 seconds to complete.

Error -330, “Self test failed” is generated if the selftest fails.

NOTE

Manual operation of internal diagnostics will affect normal Receiver

operation, including disruption of any or all of the following: GPS satellite

tracking, reference oscillator frequency, 1 PPS output timing, and Receiver

status information. When invoked manually, any of these diagnostics should

be considered to be destructive tests.

The following elements and functions are tested:

CPU

EPROM

RAM

EEPROM

UART

QSPI

FPGA logic

Interpolators

GPS engine

Power supply levels

Reference oscillator

Response

A value of 0 indicates the tests passed, a non-zero value indicates the selftest

was not completed or was completed with errors detected.

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Chapter 5 Command Reference

Operating Status

Assessing Receiver Health ______________________ (continued)

RESPONSE FORMAT

:DIAGnostic:LIFetime:COUNt?

Returns the lifetime count, indicating the total powered-on time.

This query returns the lifetime count, indicating the total powered-on time.

Response

Range of the integer is 0 to 4,294,967,296 with a resolution of 1. Each count

represents three hours of operation.

RESPONSE FORMAT

:DIAGnostic:TEST? . . .

Returns information for user-specified test.

This query returns information for user-specified test.

Expanded Syntax

:DIAGnostic:TEST? ALL or DISPlay or PROCessor or RAM or EEPRom or UART or QSPI

or FPGA or INTerpolator or GPS or POWer.

Response

A value of 0 (zero) indicates test passed.

Parameter

ALL returns test information for all of the tests.

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Chapter 5 Command Reference

Operating Status

Assessing Receiver Health ______________________ (continued)

RESPONSE FORMAT

:DIAGnostic:TEST:RESult?

Returns the result of the last test and the type of test performed.

dd, XYZ

This query returns the result of the last test and the type of test performed.

Use this query, for example, following powerup to check the outcome of the

powerup selftest.

Response

A value of 0 indicates test passed. Non-zero value indicates test failed.

The literal or alphanumeric characters portion of the response identifies the

specific test.

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Chapter 5 Command Reference

System Time

The GPS Receiver is designed to allow you access to a very accurate system

clock that provides both date and time, to customize the clock for a local time

zone, to identify the exact time, to identify the accumulated time difference (in

seconds) between the GPS and UTC timelines, and to monitor and adjust for

leap second occurrences.

The following commands are provided to allow you to monitor and control the

system date and time.

" Identifying Time of Next 1 PPS Reference Edge

:PTIMe:TCODe?

" Reading Current Time

:PTIMe:DATE?

:PTIMe:TIME?

:SYSTem:DATE?

:SYSTem:TIME?

:PTIMe:TIME:STRing?

" Applying Local Time Zone Offset

:PTIMe:TZONe ...

:PTIMe:TZONe?

" Defining the 1 PPS Reference Edge (59551A Only)

:PTIMe:PPS:EDGE ...

:PTIMe:PPS:EDGE?

" Reading Leap Second Status

:PTIMe:LEAPsecond:ACCumulated?

:PTIMe:LEAPsecond:DATE?

:PTIMe:LEAPsecond:DURation?

:PTIMe:LEAPsecond:STATe?

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Chapter 5 Command Reference

System Time

Identifying Time of Next 1 PPS Reference Edge __________

RESPONSE FORMAT

:PTIMe:TCODe?

ASCII Data

Returns timecode message 980 to 20 ms prior to 1 PPS of

indicated time.

This query returns timecode message 980 to 20 ms prior to 1 PPS of indicated

time. This special query provides not only accurate time but also provides the

user the opportunity to correctly correlate this time with a corresponding

1 PPS edge.

Response

The query response provides the following type of information:

•

date and time of next on-time edge,

Time Figure of Merit,

Frequency Figure of Merit,

leap second indicator,

alarm indication, and

service request.

An example response is:

T2199505112055233000049

This example is in the "T2YYYYMMDDHHMMSSMFLRVcc" format, where

indicates a timecode message.

YYYYMMDD is the calendar date at the next 1 PPS on-time edge.

HHMMSS

is the 24 hour time at the next 1 PPS on-time edge.

Note that this value is influenced by the ptim:tzon setting.

is time figure of merit.

is frequency figure of merit.

is leapsecond indicator (- means a -1 leapsecond is pending,

0 means no leapsecond pending, + means a 1 leapsecond is

pending).

is the request for service bit from the status system (0 = no

service requested, 1 = service requested). An alarm will be

generated when this byte transitions to 1.

is validity byte. 1 indicates that time-related information isn't

valid, 0 indicates that it is valid.

is the checksum of the prior bytes (two Hex bytes).

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Chapter 5 Command Reference

System Time

Reading Current Time____________________________________

RESPONSE FORMAT

:PTIMe:DATE?

:SYSTem:DATE?

Returns the current calendar date.

dd, dd, dd

This query returns the current calendar date. The local calendar date is always

referenced to UTC time, offset by any local time zone value that has been

provided by the user. The year, month, and day are returned.

Response

Three fields are separated by commas: <year>,<month>,<day>.

•

The <year> range is 1994 to 2077.

The <month> range is 1 to 12.

The <day> range is 1 to 31.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet. Sending this query before the

first lock will generate error -230.

RESPONSE FORMAT

:PTIMe:TIME?

:SYSTem:TIME?

Returns the current 24-hour time.

dd, dd, dd

This query returns the current 24-hour time. The local time is always

referenced to UTC time, offset by any local time zone value that has been

provided by the user. The hour, minute, and second is returned.

Response

Three fields are separated by commas: <hour>,<minute>,<second>.

•

The <hour> range is 0 to 23.

The <minute> range is 0 to 59.

The <second> range is 0 to 60. The value of 60 only occurs as the UTC

leapsecond.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet. Sending this query before the

first lock will generate error -230.

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Chapter 5 Command Reference

System Time

Reading Current Time__________________________ (continued)

RESPONSE FORMAT

:PTIMe:TIME:STRing?

Returns the current 24-hour time suitable for display.

“XYZ”

This query returns the current 24-hour time suitable for display (for example,

15:23:06).

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet. Sending this query before the

first lock will generate error -230.

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Chapter 5 Command Reference

System Time

Applying Local Time Zone Offset _________________________

:SYSTem:PRESet

:PTIMe:TZONe . . .

Sets the time zone local time offset to provide an offset from UTC

to serve as the basis for all reported time.

0,0

NON-VOLATILE

This command sets the time zone local time offset to provide an offset from

Universal Coordinated Time (UTC) to serve as the basis for all reported time.

The local 24-hour time and local calendar date depend on the present setting

of the time zone parameter, which is used to indicate the offset from UTC.

Typical application of this command is to account for time zone differences

between the installed Receiver location and the prime meridian at Greenwich,

which uses UTC uncorrected.

Expanded Syntax

:PTIMe:TZONe <hour>, <minutes>

Parameter

•

The <hour> range is -12 to +12, and is rounded to the nearest integer.

The optionally supplied <minute> range -59 to +59, and is rounded to the

nearest integer. The <minute> is defaulted to 0 if not supplied.

Context Dependencies

:SYSTem:PRESet sets the time zone to zero (0,0).

RESPONSE FORMAT

:PTIMe:TZONe?

Returns the local time zone offset.

dd, dd

This query returns the local time zone offset.

Response

The first returned value is offset hours. The second returned value is offset

minutes.

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Chapter 5 Command Reference

System Time

Defining the 1 PPS Reference Edge (59551A Only) ____

59551A

:SYSTem:PRESet

:PTIMe:PPS:EDGE . . .

Selects the polarity of the 1 PPS on-time edge.

RISing

NON-VOLATILE

This command selects the polarity of the 1 PPS on-time edge.

Expanded Syntax

:PTIMe:PPS:EDGE RISing or FALLing

Parameter

The RISing parameter sets the 1 PPS rising edge as the on-time edge.

The FALLing parameter sets the 1 PPS falling edge as the on-time edge.

59551A

RESPONSE FORMAT

:PTIMe:PPS:EDGE?

Returns the polarity of the 1 PPS on-time edge.

XYZ

This query returns the polarity of the 1 PPS on-time edge.

Response

RIS indicates that the 1 PPS on-time edge is the rising edge.

FALL indicates that the 1 PPS on-time edge is the falling edge.

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Chapter 5 Command Reference

System Time

Reading Leap Second Status ______________________________

RESPONSE FORMAT

:PTIMe:LEAPsecond:ACCumulated?

Returns the leap second difference accumulated between GPS

time and UTC time since the beginning of GPS time. The time

units are seconds.

This query returns the leap second difference accumulated between GPS time

and UTC time since the beginning of GPS time. The time units are seconds.

Response

An example response is:

+10

which indicates that the accumulated leap second difference between the GPS

time and UTC is 10 seconds.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet. Sending this query before the

first lock will generate error -230.

Theory

The leap second value is initialized during the power-on sequence by

evaluating :PTIMe:LEAPsecond:ACC = GPS time - UTC time. In July 1994,

the value was 10 seconds.

The value is automatically adjusted immediately following the occurrence of a

leap second correction to the UTC time scale. When a 1 leap second addition is

made to the UTC time scale, the extra second delays the arrival of midnight

UTC causing :PTIM:LEAP:ACC? to increase by 1 second. When a 1 leap second

subtraction is made to the UTC time scale, the missing second hastens the

arrival of UTC midnight causing :PTIM:LEAP:ACC? to decrease by 1 second.

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Chapter 5 Command Reference

System Time

Reading Leap Second Status ____________________ (continued)

RESPONSE FORMAT

:PTIMe:LEAPsecond:DATE?

Returns the UTC calendar date of next leap second.

dd, dd, dd

This query returns the UTC calendar date of next leap second. The year,

month, and day are returned.

Response

Three fields are separated by commas: <year>,<month>,<day>.

•

The <year> range is 1994 to 2077.

The <month> range is 1 to 12.

The <day> range is 1 to 31.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet, or if no leap second is pending.

Sending this query before the first lock or if no leap second is pending will

generate error -230.

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Chapter 5 Command Reference

System Time

Reading Leap Second Status ____________________ (continued)

RESPONSE FORMAT

:PTIMe:LEAPsecond:DURation?

Returns the duration of the minute corrected by the next leap

second.

This query identifies whether a leap second is pending, distinguishes between

leap seconds which extend the minute, and leap seconds which shorten the

minute. This query returns the duration of the minute corrected by the next

leap second. The duration units are seconds.

Response

Returns a value of 59, 60 or 61:

•

A value of 59 indicates subtraction of 1 second is pending.

A value of 60 indicates no leap second pending.

A value of 61 indicates addition of 1 second is pending.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet, or if no leap second is pending.

Sending this query before the first lock or if no leap second is pending will

generate error -230.

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Chapter 5 Command Reference

System Time

Reading Leap Second Status ____________________ (continued)

RESPONSE FORMAT

:PTIMe:LEAPsecond:STATe?

Identifies if leap second is pending.

0 or 1

This query identifies if a leap second is pending. This query looks ahead to

indicate a pending leap second.

Response

A value of 0 indicates no leap second is pending.

A value of 1 indicates a leap second is pending. The leap second adjustment can

be either the addition of a second or the subtraction of a second.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the

Powerup Status Register) or :SYSTem:PRESet (but is valid if no leap second is

pending). Sending this query before the first lock will generate error -230.

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Chapter 5 Command Reference

Programmable Pulse Output (59551A Only)

Programmable Pulse Output

(59551A Only)

The Programmable Pulse output feature provides a means of using the GPS

Receiver as a pulse generator. The pulse output, which is programmable by the

user, can either generate a stream of pulses at a specified start time and

repetition interval, or it can produce a single pulse at a specified time and then

stop.

The following commands are provided to allow you to operate and control the

programmable output of the 59551A GPS Receiver.

Note that the configuring of the Programmable Pulse output requires

consideration of five settings: start date, start time, continuous on/off, pulse

period, and pulse polarity. Changing any one of the settings will stop any

previously configured pulse stream and reassert all five settings. If the start

date has already passed when you modify the repetition interval, the pulse

output will halt until you provide a new start date.

:PULSe:CONTinuous:PERiod ...

:PULSe:CONTinuous:PERiod?

:PULSe:CONTinuous:STATe ...

:PULSe:CONTinuous:STATe?

:PULSe:REFerence:EDGE ...

:PULSe:REFerence:EDGE?

:PULSe:STARt:DATE ...

:PULSe:STARt:DATE?

:PULSe:STARt:TIME ...

:PULSe:STARt:TIME?

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Chapter 5 Command Reference

Programmable Pulse Output (59551A Only)

59551A

:SYSTem:PRESet

:PULSe:CONTinuous:PERiod . . .

Sets the interval between pulses in seconds.

NON-VOLATILE

This command sets the interval between pulses in seconds.

Expanded Syntax

:PULSe:CONTinuous:PERiod <seconds>

Parameter

The <seconds> parameter range is 1 to 31536000, equivalent to one year.

Resolution is 1.

Context Dependencies

The interval set by this command is only used if :PULSe:CONTinuous:STATe

is ON.

59551A

RESPONSE FORMAT

:PULSe:CONTinuous:PERiod?

Returns the interval between pulses in seconds.

This query returns the interval between pulses in seconds.

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Chapter 5 Command Reference

Programmable Pulse Output (59551A Only)

59551A

:SYSTem:PRESet

:PULSe:CONTinuous:STATe . . .

Controls whether the Programmable Pulse output will be just one

pulse or a sequence of pulses.

OFF

NON-VOLATILE

This command controls whether the Programmable Pulse output will be just

one pulse or a sequence of pulses.

Expanded Syntax

:PULSe:CONTinuous:STATe ON or OFF

Parameter

OFF selects one pulse. ON selects a sequence of pulses.

Context Dependencies

With either state (OFF or ON) the output commences at the time and date

defined by :PULSe:STARt:DATE and :PULSe:STARt:TIME commands.

59551A

RESPONSE FORMAT

:PULSe:CONTinuous:STATe?

Identifies whether the Programmable Pulse output is set to output

a single pulse or a sequence of pulses.

0 or 1

This query identifies whether the Programmable Pulse output is set to output

a single pulse or a sequence of pulses.

Response

•

A value of 0 indicates the Receiver is set to output one pulse.

A value of 1 indicates the Receiver is set to output a sequence of pulses.

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Chapter 5 Command Reference

Programmable Pulse Output (59551A Only)

59551A

:SYSTem:PRESet

:PULSe:REFerence:EDGE . . .

Selects the polarity of the Programmable Pulse on-time edge.

RISing

NON-VOLATILE

This command selects the polarity of the Programmable Pulse on-time edge.

Expanded Syntax

:PULSe:REFerence:EDGE RISing or FALLing

Parameter

The RISing parameter sets the Programmable Pulse rising edge as the on-time

edge.

The FALLing parameter sets the Programmable Pulse falling edge as the

on-time edge.

59551A

RESPONSE FORMAT

:PULSe:REFerence:EDGE?

Returns the polarity of the Programmable Pulse on-time edge.

XYZ

This query returns the polarity of the Programmable Pulse on-time edge.

Response

RIS indicates that the Programmable Pulse on-time edge is the rising edge.

FALL indicates that the Programmable Pulse on-time edge is the falling edge.

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Chapter 5 Command Reference

Programmable Pulse Output (59551A Only)

59551A

:SYSTem:PRESet

:PULSe:STARt:DATE . . .

Identifies the date when the individual pulse (or first pulse of the

pulse sequence) is generated at the Programmable Pulse output.

1994, 1, 1

NON-VOLATILE

This command identifies the date when the individual pulse (or first pulse of

the pulse sequence) is generated at the Programmable Pulse output.

Expanded Syntax

:PULSe:STARt:DATE <four-digit year>,<month>,<day>

Parameter

•

The <four-digit year> range is 1994 to 3000.

The <month> range is 1 to 12.

The <day> range is 1 to 31.

Context Dependencies

If you select a date and time which occurs prior to the current time or prior to

the completion of powerup and first GPS lock, the Receiver will not successfully

find a start—and therefore will produce no pulses.

If the Receiver has been set up to use a time zone offset to produce local date

and time, the parameters provided should also be expressed as local date and

time.

59551A

RESPONSE FORMAT

:PULSe:STARt:DATE?

Returns the date when the individual pulse (or first pulse of the

pulse sequence) is generated at the Programmable Pulse output.

dd, dd, dd

This query returns the date when the individual pulse (or first pulse of the

pulse sequence) is generated at the Programmable Pulse output. This query

returns year, month, and day.

Response

Three fields are separated by commas: <four-digit year>,<month>,<day>.

•

The <four-digit year> range is 1994 to 3000.

The <month> range is 1 to 12.

The <day> range is 1 to 31.

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Chapter 5 Command Reference

Programmable Pulse Output (59551A Only)

59551A

:SYSTem:PRESet

:PULSe:STARt:TIME . . .

Identifies the time when the individual pulse (or first pulse of the

pulse sequence) is generated at the Programmable Pulse output.

0,0,0

NON-VOLATILE

This command identifies the time when the individual pulse (or first pulse of

the pulse sequence) is generated at the Programmable Pulse output.

Expanded Syntax

:PULSe:STARt:TIME <hour>,<minute>,<second>

Parameter

Three fields are separated by commas: <hour>,<minute>, <second>.

•

The <hour> range is 0 to 23.

The <minute> range is 0 to 59.

The <second> range is 0 to 59.

Context Dependencies

If you select a date and time which occurs prior to the current time or prior to

the completion of powerup and first GPS lock, the Receiver will not successfully

find a start—and therefore will produce no pulses.

If the Receiver has been set up to use a time zone offset to produce local date

and time, the parameters provided should also be expressed as local date and

time.

59551A

RESPONSE FORMAT

:PULSe:STARt:TIME?

Returns the time when the individual pulse (or first pulse of the

pulse sequence) is generated at the Programmable Pulse output.

dd, dd, dd

This query returns the time when the individual pulse (or first pulse of the

pulse sequence) is generated at the Programmable Pulse output.

Response

Three fields are separated by commas: <hour>, <minute>, <second>.

•

The <hour> range is 0 to 23.

The <minute> range is 0 to 59.

The <second> range is 0 to 59.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

The time stamping feature allows you to use the Receiver with equipment such

as a fault analyzer or a surge detector that produces a TTL edge when some

important event happens in the base station. The Receiver has three time

tagging inputs (Time Tag 1, Time Tag 2, Time Tag 3) which record the time

of occurrence of TTL edge(s).

The following commands are provided to allow you to tag and record events

such as power surges and power outages.

" Defining the Time-stamped Edge

:SENSe:TSTamp<channel>:EDGE ...

:SENSe:TSTamp<channel>:EDGE?

" Clearing Time Stamp Memory

:SENSe:DATA:CLEar

:SENSe:DATA:CLEar ...

" Reading Time Stamps

:SENSe:DATA? ...

:FORMat:DATA ...

:FORMat:DATA?

:SENSe:DATA:POINts?

:SENSe:DATA:POINts? ...

:SENSe:DATA:TSTamp? ...

" Processing Memory Overflow

:SENSe:DATA:MEMory:OVERflow:COUNt?

:SENSe:DATA:MEMory:OVERflow:COUNt? ...

:SENSe:DATA:MEMory:SAVE ...

:SENSe:DATA:MEMory:SAVE?

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Defining the Time-stamped Edge _________________________

59551A

:SYSTem:PRESet

:SENSe:TSTamp<channel>:EDGE . . .

Selects the polarity of the edges the Receiver will time stamp.

RISing

NON-VOLATILE

This command selects the polarity of the edges the Receiver will time stamp.

Expanded Syntax

:SENSe:TSTamp1:EDGE RISing or FALLing

:SENSe:TSTamp2:EDGE RISing or FALLing

:SENSe:TSTamp3:EDGE RISing or FALLing

Parameter

•

The RISing parameter sets the time-stamped edge as the rising edge.

The FALLing parameter sets the time-stamped edge as the falling edge.

59551A

RESPONSE FORMAT

:SENSe:TSTamp<channel>:EDGE?

Returns the polarity of the edges the Receiver will time stamp.

XYZ

This query returns the polarity of the edges the Receiver will time stamp.

Response

RIS indicates that the time-stamped edge is the rising edge.

FALL indicates that the time-stamped edge is the falling edge.

59551A

:SENSe:DATA:CLEar

Clears the data in the measurement buffer for all Time Tag inputs.

EVENT

This command clears the data in the measurement buffer and clears the

overflow counts for all Time Tag inputs.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

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Event Time Stamping (59551A Only)

Clearing Time Stamp Memory ____________________________

59551A

:SENSe:DATA:CLEar . . .

Clears the data in the time stamp measurement buffer for the user-

specified Time Tag input.

EVENT

This command clears the data in the time stamp measurement buffer for the

user-specified Time Tag input. Use "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

to select one input.

Expanded Syntax

:SENSe:DATA:CLEar "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Parameter

"TSTamp 1" clears the data in Time Tag 1 input buffer.

"TSTamp 2" clears the data in Time Tag 2 input buffer.

"TSTamp 3" clears the data in Time Tag 3 input buffer.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers.

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Event Time Stamping (59551A Only)

Reading Time Stamps ____________________________________

59551A

RESPONSE FORMAT

:SENSe:DATA? . . .

FORMAT = ASCii

Outputs data from the one specified time stamp measurement

buffer.

dd, ...

FORMAT = INTeger

BINARY Data

This query outputs data from the one specified time stamp measurement buffer

(or Time Tag input). This query does not clear the buffer. Each time stamp

provides the year, month, day, hours, minutes, seconds, milliseconds,

microseconds, nanoseconds, and TFOM (Time Figure of Merit).

Expanded Syntax

:SENSe:DATA? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Response

If the format is ASCii (the default format), the response is a sequence of

comma-separated integers.

If the format is INTeger, the response is BINARY Data (see Table B-3, in

Appendix B, “Command Syntax and Style,” in this guide for details).

To determine which format is selected, use query :FORmat:DATA?.

Parameter

Use "TSTamp 1" or "TSTamp 2" or "TSTamp 3" to select one input at a time:

•

"TSTamp 1" outputs the data from Time Tag 1 input buffer.

"TSTamp 2" outputs the data from Time Tag 2 input buffer.

"TSTamp 3" outputs the data from Time Tag 3 input buffer.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

Time stamps are not collected until after the Receiver has completed its

powerup, and has reached initial lock to GPS.

Time stamps are not collected while the user is reading/clearing or otherwise

accessing the time stamp buffers.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Reading Time Stamps __________________________ (continued)

59551A

:SYSTem:PRESet

:FORMat:DATA . . .

Selects output format for the time stamps.

ASCii

NON-VOLATILE

This command selects the output format for the time stamps.

Expanded Syntax

:FORMat:DATA ASCii or INTeger

Parameter

If the format is ASCii (the default format), the response is a sequence of

comma-separated integers.

If the format is INTeger, the response to the :SENSe:DATA? query is BINARY

Data (see Table B-3, in Appendix B, “Command Syntax and Style,” in this

guide for details).

When ASCii formatting is selected the output stream data is buffered. In

general, INT mode will provide faster output than ASC, but will require special

data-handling routines to interpret the BINARY Data.

59551A

RESPONSE FORMAT

:FORMat:DATA?

Returns the output format for time stamp data.

XYZ

This query returns the output format for time stamp data.

Response

ASC or INT is returned.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Reading Time Stamps __________________________ (continued)

59551A

RESPONSE FORMAT

:SENSe:DATA:POINts?

Returns the number of time stamps in each of the three Time Tag

inputs.

dd, ...

This query returns the number of time stamps in each of the three Time Tag

inputs.

Response

Returns three comma-separated integers corresponding to the number of time

stamps recorded for inputs 1, 2, and 3.

The numeric range for each integer is 0 to 256.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

Time stamps are not collected until after the Receiver has completed its

powerup and has reached initial GPS lock.

59551A

RESPONSE FORMAT

:SENSe:DATA:POINts? . . .

Returns the number of time stamps recorded for the one specified

Time Tag input.

This query returns the number of time stamps recorded for the one specified

Time Tag input. Use "TSTamp 1", "TSTamp 2", or "TSTamp 3" to select one

input.

Expanded Syntax

:SENSe:DATA:POINts? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Response

Returns an integer corresponding to the number of time stamps recorded for

the specified input.

•

Numeric range is 0 to 256.

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Event Time Stamping (59551A Only)

Reading Time Stamps __________________________ (continued)

Parameter

"TSTamp 1"queries for the number of points in Time Tag 1 input buffer.

"TSTamp 2" queries for the number of points in Time Tag 2 input buffer.

"TSTamp 3" queries for the number of points in Time Tag 3 input buffer.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

Time stamps are not collected until after the Receiver has completed its

powerup and has reached initial GPS lock.

59551A

RESPONSE FORMAT

:SENSe:DATA:TSTamp? . . .

Returns a single time stamp.

dd, ...

This query returns a single time stamp. Use "TSTamp 1" or "TSTamp 2" or

"TSTamp 3" to select an input channel. Use <time stamp entry> to select a

single time stamp recorded on that input.

Expanded Syntax

:SENSe:DATA:TSTamp? "TSTamp 1" or "TSTamp 2" or "TSTamp 3",

Response

The query response represents the single time stamp requested.

The query response is a sequence of ten comma-separated integers constituting

a single time stamp. The time stamp provides the year, month, day, hours,

minutes, seconds, milliseconds, microseconds, nanoseconds, and TFOM (Time

Figure of Merit).

For example,

:SENSe:DATA:TSTamp? "TSTamp 2", 37

Selects the 37th time stamp recorded on Time Tag Input 2.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Reading Time Stamps __________________________ (continued)

Parameter

<time tag input> parameter:

•

"TSTamp 1" to select Time Tag 1 input buffer.

"TSTamp 2" to select Time Tag 2 input buffer.

"TSTamp 3" to select Time Tag 3 input buffer.

<time stamp entry> parameter range is 1 to 256.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

Time stamps are not collected until after the Receiver has completed its

powerup and has reached initial GPS lock.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Processing Memory Overflows ____________________________

59551A

RESPONSE FORMAT

:SENSe:DATA:MEMory:OVERflow:COUNt?

Returns an overflow count for each of the three Time Tag inputs.

d.dEe, ...

This query returns an overflow count for each of the three Time Tag inputs.

An “overflow count” occurs after 256 time stamps have been recorded. When

any additional events are detected at the input, the overflow count increments.

If memory management protocol has been set to “FIRST,” the first 256 time

stamps are recorded. The overflow count indicates the number of time stamps

which followed the last recorded stamp, and which were discarded.

If memory management protocol has been set to “LAST,” the most recent

256 time stamps are recorded. The overflow count indicates the number of

stamps which were collected prior to the first recorded stamp, and which were

overwritten.

Response

Returns three comma-separated floating-point numbers corresponding to the

overflow count of each of the three inputs: 1, 2, 3.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

Time stamps are not collected until after the Receiver has completed its

powerup and has reached initial GPS lock.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Processing Memory Overflows __________________ (continued)

59551A

RESPONSE FORMAT

:SENSe:DATA:MEMory:OVERflow:COUNt? . . .

Returns an overflow count for the selected Time Tag input.

d.dEe

This query returns an overflow count for the selected Time Tag input.

Use "TSTamp 1", "TSTamp 2", or "TSTamp 3" to select or query one input at a

time.

Expanded Syntax

:SENSe:DATA:MEMory:OVERflow:COUNt? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Response

Returns one floating-point number corresponding to the overflow count of the

selected Time Tag input.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow

counts.

Time stamps are not collected until after the Receiver has completed its

powerup and has reached initial GPS lock.

59551A

:SYSTem:PRESet

:SENSe:DATA:MEMory:SAVE . . .

Sets the Receiver’s memory management protocol.

FIRSt

NON-VOLATILE

This command sets the Receiver’s memory management protocol.

Expanded Syntax

:SENSe:DATA:MEMory:SAVE FIRSt or LAST

Parameter

FIRSt retains time stamps for the first 256 events detected.

LAST retains time stamps of the last (most recent) 256 events detected.

Context Dependencies

:SYSTem:PRESet sets memory management protocol to retain time stamps for

FIRSt 256 events.

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Chapter 5 Command Reference

Event Time Stamping (59551A Only)

Processing Memory Overflows __________________ (continued)

59551A

RESPONSE FORMAT

:SENSe:DATA:MEMory:SAVE?

Returns the state of the memory management protocol.

XYZ

This query returns the state of the memory management protocol.

Response

FIRSt indicates that the memory retains time stamps for the first 256 events

detected.

LAST indicates that the memory retains time stamps for the last (most recent)

256 events detected.

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Chapter 5 Command Reference

Serial Interface Communication

The 59551A and 58503B GPS Receivers provide a set of commands that allow

you to configure the serial interface port(s) for instrument communications. A

set of special commands is provided for the 59551A Receiver since it has two

different serial ports (PORT 1, PORT 2).

Both Receivers have the rear-panel RS-232C serial interface port (PORT 1).

The 59551A has an additional front-panel RS-232C serial interface port

(PORT 2).

The following commands are provided to allow you to configure the ports.

! Configuring I/O Port 1 <port> = SERial1 or SERial

Configuring I/O Port 2 <port> = SERial2 (59551A Only)

:SYSTem:COMMunicate?

:SYSTem:COMMunicate:<port>:BAUD ...

:SYSTem:COMMunicate:<port>:BAUD?

:SYSTem:COMMunicate:SERial1:BITS ...

:SYSTem:COMMunicate:<port>:BITS?

:SYSTem:COMMunicate:<port>:FDUPlex ...

:SYSTem:COMMunicate:<port>:FDUPlex?

:SYSTem:COMMunicate:<port>:PACE ...

:SYSTem:COMMunicate:<port>:PACE?

:SYSTem:COMMunicate:<port>:PARity ...

:SYSTem:COMMunicate:<port>:PARity?

:SYSTem:COMMunicate:SERial1:SBITs ...

:SYSTem:COMMunicate:<port>:SBITs?

(59551A)

! Recovering the Last Query Response

:DIAGnostic:QUERy:RESPonse?

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Chapter 5 Command Reference

Serial Interface Communication

Configuring I/O Ports _____________________________________

RESPONSE FORMAT

:SYSTem:COMMunicate?

Identifies which serial port is being used.

XYZ

This query identifies which serial port is being used. Use this query when the

Receiver is installed out of sight or at a remote location. The distinction

between SERIAL1 and SERIAL2 is required in communication commands for

setting parameters such as baud and parity.

Response

SER1 or SER2 is returned.

:SYSTem:PRESet

:SYSTem:COMMunicate:<port>:BAUD . . .

R, F

Sets the baud rate of specified port.

Not affected

NON-VOLATILE

This command sets the baud rate of the specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:BAUD 1200 or 2400 or 9600 or 19200

:SYSTem:COMMunicate:SERial2:BAUD 1200 or 2400 or 9600 or 19200

Parameter

The possible baud rate values that can be entered are 1200, 2400, 9600, or

19200.

Context Dependencies

The baud rate value is stored in non-volatile memory. It is unaffected by

powerup and :SYSTem:PRESet.

:SYSTem:COMMunicate:<port>:PRESet sets the baud rate to 9600, which is

the factory-default value.

Must be received via the specified I/O port.

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Chapter 5 Command Reference

Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

RESPONSE FORMAT

R, F

:SYSTem:COMMunicate:<port>:BAUD?

Returns the baud rate of specified port.

This query returns the baud rate of specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:BAUD?

:SYSTem:COMMunicate:SERial2:BAUD?

59551A

:SYSTem:PRESet

:SYSTem:COMMunicate:SERial1:BITS . . .

Sets the data bits value of PORT 1.

Not affected

NON-VOLATILE

This command sets the data bits of PORT 1.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:BITS 7 or 8

Parameter

The possible data bits values that can be entered are 7 or 8.

Context Dependencies

The data bits value is stored in non-volatile memory. It is unaffected by

powerup and :SYSTem:PRESet.

:SYSTem:COMMunicate:SERial1:PRESet sets the data bits to 8, which is the

factory-default value.

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Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

RESPONSEFORMAT

R, F

:SYSTem:COMMunicate:<port>:BITS?

Returns the data bits value of specified port.

This query returns the data bits value of the specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:BITS?

:SYSTem:COMMunicate:SERial2:BITS?

:SYSTem:PRESet

:SYSTem:COMMunicate:<port>:FDUPlex . . .

R, F

Sets the duplex state of specified port.

Not affected

NON-VOLATILE

This command sets the duplex state of the specified port. Use this command

when you cannot see on the computer screen the characters you are typing for

your command.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:FDUPlex ON or OFF

:SYSTem:COMMunicate:SERial2:FDUPlex ON or OFF

Parameter

ON enables echoing of the characters you type (i.e., when typing a command,

the ON state allows you to see on the computer screen the characters you type).

OFF disables the echoing of the characters you type.

Context Dependencies

The duplex state is stored in non-volatile memory. It is unaffected by powerup

and :SYSTem:PRESet.

SYSTem:COMMunicate:<port>:PRESet sets the duplex state to ON, which is

the factory-default state.

Must be received via the specified I/O port.

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Chapter 5 Command Reference

Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

RESPONSEFORMAT

R, F

:SYSTem:COMMunicate:<port>:FDUPlex?

Returns the duplex state of the specified port.

0 or 1

This query returns the duplex state of the specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:FDUPlex?

:SYSTem:COMMunicate:SERial2:FDUPlex?

Response

A value of 0 indicates echo is OFF.

A value of 1 indicates echo is ON.

:SYSTem:PRESet

:SYSTem:COMMunicate:<port>:PACE . . .

R, F

Sets flow control of the specified port.

Not affected

NON-VOLATILE

This command sets flow control of the specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:PACE XON or NONE

:SYSTem:COMMunicate:SERial2:PACE XON or NONE

Parameter

The choices are XON or NONE.

Context Dependencies

The software pacing or flow control state is stored in non-volatile memory. It is

unaffected by powerup and :SYSTem:PRESet.

:SYSTem:COMMunicate:<port>:PRESet sets the flow control to NONE, which

is the factory-default state.

Must be received via the specified I/O port.

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Chapter 5 Command Reference

Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

RESPONSEFORMAT

R, F

:SYSTem:COMMunicate:<port>:PACE?

Returns flow control state of the specified port.

XYZ

This query returns the flow control state of specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:PACE?

:SYSTem:COMMunicate:SERial2:PACE?

Response

XON or NONE is returned.

:SYSTem:PRESet

:SYSTem:COMMunicate:<port>:PARity . . .

R, F

Sets parity of the specified port.

Not affected

NON-VOLATILE

This command sets parity of the specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:PARity: EVEN or ODD or NONE

:SYSTem:COMMunicate:SERial2:PARity: EVEN or ODD or NONE or ONE

Parameter

The choices for SERial1 are EVEN, ODD, or NONE.

The choices for SERial2 are EVEN, ODD, NONE, or ONE.

Context Dependencies

The parity state is stored in non-volatile memory. It is unaffected by powerup

and :SYSTem:PRESet.

:SYSTem:COMMunicate:<port>:PRESet sets the parity to NONE, which is the

factory-default state.

If parity is enabled, the Receiver sends/receives 7 data bits plus 1 parity bit.

If parity is disabled, the Receiver sends/receives 8 data bits.

Must be received via the specified I/O port.

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Chapter 5 Command Reference

Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

RESPONSE FORMAT

R, F

:SYSTem:COMMunicate:<port>:PARity?

Returns parity setting of the specified port.

XYZ

This query returns the parity setting of the specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:PARity?

:SYSTem:COMMunicate:SERial2:PARity?

Response

EVEN, ODD, NONE, or ONE is returned.

59551A

:SYSTem:PRESet

:SYSTem:COMMunicate:SERial1:SBITs . . .

Sets the stop bits value of PORT 1.

Not affected

NON-VOLATILE

This command sets the stop bits value of PORT 1.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:SBITs 1 or 2

Parameter

The possible stop bits values that can be entered are 1 or 2.

Context Dependencies

The stop bits value is stored in non-volatile memory. It is unaffected by

powerup and :SYSTem:PRESet.

:SYSTem:COMMunicate:SERial1:PRESet sets the stop bits value to 1, which

is the factory-default value.

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Chapter 5 Command Reference

Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

RESPONSE FORMAT

R, F

:SYSTem:COMMunicate:<port>:SBITs?

Returns the stop bits value of the specified port.

This query returns the stop bits value of specified port.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:SBITs?

:SYSTem:COMMunicate:SERial2:SBITs?

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Chapter 5 Command Reference

Serial Interface Communication

Recovering the Last Query Response _____________________

RESPONSE FORMAT

:DIAGnostic:QUERy:RESPonse?

Returns the last response item issued through the Receiver's

serial interface for use in an error recovery process.

Format depends on the last

issued query.

This query returns the last response item issued through the Receiver’s serial

interface for use in an error recovery process.

In the case of a serial interface data transmission error, this query can be used

to get the last response item which may otherwise be unavailable because of

the side effects of the original command. For example, the :SYST:ERRor? query

removes the oldest entry from the error queue, so to see the entry again

following a data transmission error, use :DIAG:QUER:RESP? instead of

repeating the original command.

Response

The format depends on the last issued query.

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Chapter 5 Command Reference

Receiver Initialization

The following commands are provided to allow you to initialize or preset the

serial interface port(s) and the Receiver to their factory shipment values.

:SYSTem:COMMunicate:SERial1:PRESet

:SYSTem:COMMunicate:SERial2:PRESet (59551A Only)

:SYSTem:PRESet

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Chapter 5 Command Reference

Receiver Initialization

:SYSTem:COMMunicate:<port>:PRESet

Sets the specified port configuration to its factory-default

values.

EVENT

This command is an event that sets specified port parameters to their

factory-default values.

Expanded Syntax

:SYSTem:COMMunicate:SERial1:PRESet

:SYSTem:COMMunicate:SERial2:PRESet

Factory-Default Settings for PORT 1 of the 59551A

Parameter

Software Pacing

Baud Rate

Parity

Default

NONE

9600

NONE

Possible Choices

XON or NONE

1200, 2400, 9600, or 19200

EVEN, ODD, or NONE

7 or 8

Data Bits

Stop Bits

1 or 2

Full Duplex

ON or OFF

Factory-Default Settings for PORT 1 of the 58503B and PORT 2 of the

59551A

Parameter

Software Pacing

Baud Rate

Parity

Default

NONE

9600

NONE

Possible Choices

XON or NONE

1200, 2400, 9600, or 19200

EVEN, ODD, NONE, or ONE

Fixed at 7 when parity is even or odd.

Fixed at 8 when parity is none.

Fixed (no choices available)

ON or OFF

Data Bits

Stop Bits

Full Duplex

Context Dependencies

The SERial1 preset command only is valid if transmitted on the rear-panel

(PORT 1).

:SYSTem:PRESet

Restores the Receiver parameters settings to their

factory-default values.

EVENT

This command is an event that restores the Receiver parameters settings to

their factory shipment or factory-default values (see the following Table 5-2).

NOTE

Issuing this command will result in disruption of all of the following: GPS

satellite tracking, reference oscillator frequency, 1 PPS output timing, and

Receiver status information.

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Chapter 5 Command Reference

Receiver Initialization

Table 5-2. System Preset (Factory Default) Parameter Settings

Summary

Commands

:SYSTem:PRESet

*ESE ...

0 (NV ) — See footnotes on the

bottom of the next page

*SRE ...

136 (NV)

:DIAGnostic:LOG:CLEar

Log is cleared.

:DIAGnostic:LOG:COUNt?

:DIAGnostic:QUERy:RESPonse?

cleared.

:FORMat:DATA ...

:GPS:POSition ...

ASCII (NV)

N,0,0,0,E,0,0,0,0 (NV)

LAST is also set to this position.

(NV)

:GPS:POSition:HOLD:LAST?

N,0,0,0,E,0,0,0,0 (NV)

0 (NV)

:GPS:POSition:HOLD:STATe?

:GPS:POSition:SURVey:STATe ...

:GPS:POSition:SURVey:STATe:POWerup ...

ONCE

ON (NV)

:GPS:REFerence:ADELay ...

0.0 (NV)

:GPS:SATellite:TRACking:EMANgle ...

:GPS:SATellite:TRACking:IGNore:STATe? ...

:GPS:SATellite:TRACking:IGNore ...

10 (NV)

0 for every PRN.

No satellites ignored (NV)

All satellites included (NV)

1 for every PRN.

:GPS:SATellite:TRACking:INCLude ...

:GPS:SATellite:TRACking:INCLude:STATe? ...

:PTIMe:TZONe ...

0,0 (NV)

:PULSe:CONTinuous:PERiod ...

:PULSe:CONTinuous:STATe ...

1 (NV)

OFF (NV)

:PULSe:STARt:DATE ...

:PULSe:STARt:TIME ...

1994,1,1 (NV)

0,0,0 (NV)

:SENSe:DATA?

Data is cleared.

:SENSe:DATA:MEMory:OVERflow:COUNt?

:SENSe:DATA:MEMory:SAVE ...

:SENSe:DATA:POINts?

All counts are cleared (V ).

FIRSt (NV)

All responses become 0 (zero).

(V)

:SENSe:DATA:TSTamp? ...

All timestamps cleared.

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Chapter 5 Command Reference

Receiver Initialization

Table 5-2. System Preset (Factory Default) Parameter Settings

Summary (Continued)

Commands

:SYSTem:PRESet

:STATus:OPERation:ENABle ...

36 (NV)

:STATus:OPERation:HARDware:ENABle ...

:STATus:OPERation:HARDware:NTRansition ...

:STATus:OPERation:HARDware:PTRansition ...

:STATus:OPERation:HOLDover:ENABle ...

:STATus:OPERation:HOLDover:NTRansition ...

:STATus:OPERation:HOLDover:PTRansition ...

8191 (NV)

0 (NV)

5119 (NV)

8 (NV)

0 (NV)

15 (NV)

:STATus:OPERation:NTRansition ...

0 (NV)

:STATus:OPERation:POWerup:ENABle ...

:STATus:OPERation:POWerup:NTRansition ...

:STATus:OPERation:POWerup:PTRansition ...

7 (NV)

0 (NV)

7 (NV)

:STATus:OPERation:PTRansition ...

127 (NV)

:STATus:QUEStionable:CONDition:USER ...

:STATus:QUEStionable:ENABle ...

Cleared (NV)

3 (NV)

:STATus:QUEStionable:NTRansition ...

:STATus:QUEStionable:PTRansition ...

0 (NV)

2 (NV)

:SYNChronization:HOLDover:DURation?

0,0 (Even if there was a prior

holdover, its duration will be lost.)

:SYNChronization:HOLDover:DURation:THReshold ...

86400 (that is, 1 day), (NV)

POWerup

:SYNChronization:STATe?

:SYSTem:ERRor?

Error queue is cleared.

"PRIMARY"

:SYSTem:LANGuage ...

* NV stands for non-volatile memory.

** V stands for volatile memory.

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Chapter 5 Command Reference

Receiver Identification/Upgrade

The commands provided in this section allow you to query the identification of

the Receiver, and to perform firmware upgrades in the field after you obtain a

new firmware disk.

! Reading Product Identification

*IDN?

! Installing Firmware via I/O PORT 1

*CLS

:DIAGnostic:DOWNload ...

:DIAGnostic:ERASe

:DIAGnostic:ERASe?

:SYSTem:ERRor?

:SYSTem:LANGuage ...

:SYSTem:LANGuage?

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Chapter 5 Command Reference

Receiver Identification/Upgrade

Reading Product Identification ___________________________

RESPONSE FORMAT

*IDN?

Returns the Receiver identification.

ASCII Data

This query returns the Receiver identification.

Response

•

A sequence of ASCII-encoded bytes:

HEWLETT-PACKARD, 59551A, XXXXYZZZZZ, WWWW – V

where 59551A is the product model number, XXXXYZZZZZ is the product

serial number, and WWWW is the product’s firmware revision date code,

and V is the hardware revision letter.

In the product serial number (XXXXYZZZZZ):

–

XXXX is a four-digit prefix that identifies a series of instruments.

Y identifies the country in which the instrument was manufactured

(e.g., the “A” in 3426A000123 stands for America).

–

ZZZZZ is a five-digit suffix that identifies a particular instrument

within a series.

•

For example,

HEWLETT-PACKARD, 59551A,3426A00123,3422 – A

This query should be the last query in a terminated program message;

otherwise, error -440 is generated.

Context Dependencies

Preparatory to installation of new product firmware, the instrument is

switched to the “INSTALL” language, available only on PORT 1.

The “INSTALL” language includes an *IDN? query which returns the revision

identification for the installation firmware. The response format is the same as

described above for the instrument’s “PRIMARY” language, but the

identification code may be different.

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Chapter 5 Command Reference

Receiver Identification/Upgrade

Installing Firmware via I/O PORT 1 ______________________

The commands in this section represent the command set of the “INSTALL”

language. The “INSTALL” language is part of a highly-specialized set of

features used to erase the Receiver’s firmware, and to install a new firmware

revision. It should be selected only when firmware installation is required.

The “INSTALL” language offers the limited number of commands and queries

which are documented in this section. This set is designed to provide the

Receiver status and control capability required during firmware upgrade.

NOTE

The SatStat program provides a Service menu which automates firmware

installation.

*CLS

Clears errors.

EVENT

This command clears errors.

:DIAGnostic:DOWNload . . .

Sends down a MotorolaS-record.

EVENT

This command sends down a Motorola S-record.

Expanded Syntax

:DIAGnostic:DOWNload <Motorola S-record>

:DIAGnostic:ERASe

Erases the flash EEPROM.

EVENT

This command erases the flash EEPROM. It should ONLY be sent to the

Receiver as a preparatory step during firmware upgrade. Erasing flash

EEPROM will disable the instrument until flash EEPROM is reloaded with

factory-supplied instrument firmware.

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Chapter 5 Command Reference

Receiver Identification/Upgrade

Installing Firmware via I/O Port 1 ______________ (continued)

RESPONSE FORMAT

:DIAGnostic:ERASe?

Verifies flash EEPROM has been erased.

0 or 1

This query verifies the flash EEPROM has been erased.

Response

A value of 1 indicates that flash EEPROM has been erased.

This condition normally occurs when the instrument software in flash

EEPROM is erased in preparation for installation of a more recent software

revision. That is, after command :DIAG:ERASe has been issued and erase is

complete, the :DIAG:ERASe? query response is “1”.

RESPONSE FORMAT

:SYSTem:ERRor?

Returns the oldest error in the Error Queue and removes

that error from the queue (first in, first out).

dd, “XYZ”

This query returns the oldest error in the Error Queue and removes that error

from the queue (first in, first out).

See Appendix A, “Error Messages,” in this guide for detailed error information.

Response

The error response format is: <error_number>,"<error_description>", where

•

The <error_number> is an integer transferred as ASCII bytes in <NR1>

format (integer). The range is -32768 to 32767.

•

Negative error numbers are defined by the SCPI standard.

Positive error numbers are defined specifically for this Receiver.

An error number value of zero indicates that the Error Queue is empty.

The maximum length of the <error_description> is 255 characters.

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Chapter 5 Command Reference

Receiver Identification/Upgrade

Installing Firmware via I/O Port 1 ______________ (continued)

Context Dependencies

:SYSTem:PRESet clears the Error Queue.

The queue is cleared (emptied) on *CLS, power-on, or upon reading the last

error from the queue.

If the Error Queue overflows, the last error in the queue is replaced with the

error -350, "Queue overflow". Any time the queue overflows, the least recent

errors remain in the queue and the most recent error is discarded.

The maximum length of the Error Queue is 30.

:SYSTem:PRESet

:SYSTem:LANGuage . . .

“PRIMARY”

Switches the operation mode (primary or install) of the

Receiver.

NON-VOLATILE

This command switches the operation mode (primary or install) of the

Receiver.

Expanded Syntax

:SYSTem:LANGuage "INSTALL" or "PRIMARY".

Parameter

The “INSTALL” language is part of a highly-specialized set of features used to

erase the Receiver’s firmware, and to install a new firmware revision. It should

be selected only when firmware installation is required.

The “INSTALL” language offers the limited number of commands and queries

which are documented in this section. This set is designed to provide the

Receiver status and control capability required during firmware upgrade.

NOTE

The SatStat program provides a Service menu which automates firmware

installation.

The “PRIMARY” language provides the capabilities required for normal

Receiver operation. If the “INSTALL” language has been selected as part of the

firmware upgrade, the “PRIMARY” language should be selected after the

upgrade to restore normal operation.

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Chapter 5 Command Reference

Receiver Identification/Upgrade

Installing Firmware via I/O Port 1 ______________ (continued)

RESPONSE FORMAT

:SYSTem:LANGuage?

Identifies the operation mode (primary or install) of the

Receiver.

“XYZ”

This query identifies the operation mode (primary or install) of the Receiver.

Response

“INSTALL” or “PRIMARY” is returned.

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Error Messages

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Appendix A Error Messages

Introduction

This appendix explains how to read any errors from the Receiver,

discusses the error queue, types of errors and general error behavior,

and provides a table of all of the Receiver’s errors and their probable

causes.

Reading an Error

Executing the :SYSTEM:ERROR? command reads the oldest error from

the error queue and erases that error from the queue. The :SYST:ERR?

response has the form:

An example response is:

-113,"Undefined header"

Positive error numbers are specific to the Receiver. Negative error

numbers are command language related and are discussed later in this

appendix.

All errors set a corresponding bit in the Standard Event Status

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Appendix A Error Messages

Error Queue

As errors are detected, they are placed in an error queue. This queue is

first in, first out. That is, if there has been more than one error, the

first one in the queue is read out with :SYST:ERR?. Subsequent

responses continue until the queue is empty.

If the error queue overflows, the last error in the queue is replaced

with error -350, "Queue overflow". Any time the queue overflows, the

least recent errors remain in the queue, and the most recent error is

discarded. The length of the Receiver’s error queue is 30 (29 positions

for the error messages, and 1 position for the “Queue overflow” error).

Reading an error from the head of the queue removes that error from

the queue, and opens a position at the tail of the queue for a new error,

if one is subsequently detected.

When all errors have been read from the queue, further error queries

return +0, "No error".

The error queue is cleared when any of the following occur:

• Upon power-on.

• Upon receipt of a *CLS command.

• Upon reading the last item from the queue.

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Appendix A Error Messages

Error Types

Error numbers are categorized by type as shown in Table A-1. Each

error is listed in Table A-2.

Table A-1. Error Types

Error Number

Error Type

No Error

−100 to −199

−200 to −299

−300 to −350

−400 to −499

Syntactic Errors

Semantic Errors

Hardware/Firmware Errors

Query Errors

The first error described in each class (for example, −100, −200, −300,

−400) is a “generic” error.

No Error

The :SYST:ERR? response +0, "No error" indicates that the Receiver

has no errors. The error queue is empty when every error in the queue

has been read (:SYST:ERR? query) or the queue was cleared by power-

on or *CLS.

Syntactic Error

An <error number> in the range [−100 to −199] indicates that an IEEE

488.2 syntax error has been detected by the Receiver’s parser.

The occurrence of any error in this class causes the syntactic error bit

(bit 5) in the Event Status Register to be set. One of the following

events has occurred:

• An IEEE 488.2 syntax error has been detected by the parser.

That is, a controller-to-Receiver message was received that is in

violation of the IEEE 488.2 Standard. Possible violations include a

data element that violates the Receiver listening formats or whose

type is unacceptable to the Receiver.

• An unrecognized header was received. Unrecognized headers

include incorrect Receiver-specific headers and incorrect or

unimplemented IEEE 488.2 Common Commands.

Events that generate syntactic errors do not generate semantic errors,

hardware/firmware errors, or query errors.

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Appendix A Error Messages

Error Types

Semantic Error

An <error number> in the range [−200 to −299] indicates that an error

has been detected by the Receiver’s execution control block.

The occurrence of any error in this class causes the semantic error bit

(bit 4) in the Event Status Register to be set. One of the following

events has occurred:

• A <PROGRAM DATA> element following a header was evaluated

by the Receiver as outside of its legal input range or is otherwise

inconsistent with the Receiver’s capabilities.

• A valid program message could not be properly executed due to

some Receiver condition.

Semantic errors are reported by the Receiver after rounding and

expression evaluation operations have been taken place. Rounding a

numeric data element, for example, is not reported as a semantic error.

Events that generate semantic errors do not generate syntactic errors,

hardware/firmware errors, or query errors.

Hardware/Firmware Error

An <error number> in the range [−300 to −399] or [+1 to +32767]

indicates that the Receiver has detected an error that is not a syntactic

error, a query error, or a semantic error; some Receiver operations did

not properly complete, possibly due to an abnormal hardware or

firmware condition. These codes are also used for self-test response

errors. The occurrence of any error in this class causes the

hardware/firmware error bit (bit 3) in the Event Status Register to

be set.

Query Error

An <error number> in the range [−400 to −499] indicates that the

output queue control of the Receiver has detected a problem with the

message exchange protocol. The occurrence of any error in this class

should cause the query error bit (bit 2) in the Event Status Register to

be set. One of the following is true:

• An attempt is being made to read data from the output queue when

no output is either present or pending.

• Data in the output queue has been lost.

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Appendix A Error Messages

General Error Behavior

For Commands (i.e., non-query; doesn’t provide a response):

• For any command that has numeric parameters, if the value is out

of range (beyond either the min or max allowed settings), the value

will be clipped to the appropriate limit and error −222 will be

generated (data out-of-range error) as an indication that the value

wasn’t set to the requested value.

There are some commands having numeric parameters where the

clipping behavior described above doesn’t make sense. These

include the satellite include and ignore commands, and the status

system mask commands. For these commands, an out-of-bounds

value is ignored and error −222 is generated. Also, a single

out-of-bounds value may cause the entire command to be ignored.

For example, GPS:SAT:TRAC:INCL 3,87,5 will be entirely ignored

because 87 is out-of-range (i.e., 3 and 5 do not become included even

though they are in-range).

• Commands with multiple numeric parameters can produce

multiple errors. For example, if the initial date command is sent as

GPS:INIT:TIME 25,66,−7, the actual programmed value will be

23:59:00 (23 is max hour, 59 is max minute, 0 is min second) and

three out-of-range errors will be generated. As always, only a single

prompt will be returned, but in this case three errors will be in the

error queue (de-queued via SYST:ERR? or *CLS).

• Numeric parameters between in-range values are rounded to the

closest value. For example, sending GPS:REF:ADEL 1.7 ns will set

the antenna delay to 2 ns.

For Queries (response-generating commands)

• If the query produces an error, there will not be a response (other

than the prompt that always occurs).

• If the query includes a numeric parameter, and that parameter is

out of range, error −222 will be generated and there won’t be a

response (this is consistent with the prior bullet). An example of

this would be DIAG:LOG:READ? 25 when there are fewer than

25 messages in the log. Note that for this specific example, to get

the most recent log entry, simply use DIAG:LOG:READ?.

• Another way you can view this: if you get a query response you can

know that it is responding precisely to the question asked by the

query.

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Appendix A Error Messages

List of Errors

Table A-2 lists and describes the error messages

Table A-2. Error Messages

Number

Error String

Cause

No error

The error queue is empty. Every error in the queue has been read (SYSTem:ERRor?

query) or the queue was cleared by power-on or *CLS.

-100

Command error

This is the generic syntax error used if the Receiver cannot detect more specific

errors.

-101

-102

-103

-104

Invalid character

Syntax error

A syntactic element contains a character that is invalid for that type.

An unrecognized command or data type was encountered.

Invalid separator

Data type error

The parser was expecting a separator and encountered an illegal character.

The parser recognized a data element different than one allowed. For example,

numeric or string data was expected, but block data was received.

-108

-109

-112

-113

-120

Parameter not allowed

Missing parameter

More parameters were received than expected for the header.

Fewer parameters were received than required for the header.

Program mnemonic too long The header or character data element contains more than twelve characters.

Undefined header

Numeric data error

The header is undefined. For example, the command ":HELLO".

This error, as well as errors -121 through -129, is generated when parsing a data

element which appears to be numeric. This particular error message is used when

the Receiver cannot detect a more specific error.

-121

Invalid character in number An invalid character for the data type being parsed was encountered. For example, a

"9" in ocatal data.

-123

-124

Exponent too large

Too many digits

Numeric overflow.

The mantissa of a decimal numeric data element contained more than 255 digits

excluding leading zeros.

-128

-131

Numeric data not allowed

Invalid suffix

A legal numeric data element was received, but the Receiver does not accept one in

this position for the header.

The suffix does not follow the syntax described in IEEE 488.2 or the suffix is

inappropriate for the Receiver.

-134

-138

-141

-148

-150

Suffix too long

The suffix contained more than 12 characters.

Suffix not allowed

Invalid character data

Character data not allowed

String data error

A suffix was encountered after a numeric element that does not allow a suffix.

The character data element contains an invalid character.

A legal character data element was encountered where prohibited by the Receiver.

This error can be generated when parsing a string data element. This particular error

message is used if the Receiver cannot detect a more specific error.

-151

-158

Invalid string data

A string data element was expected but was invalid for some reason.

String data not allowed

A string data element was encountered but was not allowed by the Receiver at this

point in parsing.

-170

Expression error

This error can be generated when parsing an expression data element. It is used if

the Receiver cannot detect a more specific error.

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Appendix A Error Messages

List of Errors

Table A-2. Error Messages (Continued)

Number

Error String

Cause

-178

Expression data not allowed Expression data was encountered but was not allowed by the Receiver at this point

in parsing.

-200

-220

Execution error

Parameter error

This is the generic syntax error if the Receiver cannot detect more specific errors.

Indicates that a program data element error occurred. This error is used when the

Receiver cannot detect more specific errors.

-221

-222

-223

Settings conflict

Data out of range

Too much data

Indicates that a legal program data element was parsed but could not be executed

due to the current Receiver state.

Indicates that a legal program data element was parsed but could not be executed

because the interpreted value is outside the legal range defined by the Receiver.

Indicates that a legal program data element of block, expression, or string type was

received that contained more data than the Receiver could handle due to memory or

related receiver-specific requirements.

-224

Illegal parameter value

Used where exact value, from a list of possible values, was expected (but not

received).

-230

-240

Data corrupt or stale

Hardware error

No valid data available.

Indicates that a legal program command or query could not be executed because of

a hardware problem in the Receiver.

-241

Hardware missing

Indicates that a legal program command or query could not be executed because of

missing Receiver hardware.

-300

-310

-311

-315

-321

-330

-350

-360

Device-specific error

System error

This is the generic device-dependent error.

Indicates that a system error occurred.

Memory error

Occurs on EEPROM write failure.

Configuration memory lost

Out of memory

Could happen on powerup or preset if a nonvolatile memory problem is detected.

Indicates that the Receiver has detected that insufficient memory is available.

Indicates at least one failure occurred when *TST? or :DIAG:TEST? was executed.

An error occurred but was not recorded because the error queue is full.

Self-test failed

Queue overflow

Communication error

This is the generic communication error for devices that cannot detect the more

specific errors described for errors -361 through -363.

-361

-362

-363

-440

Parity error in program

message

Parity bit not correct when data received for example, on a serial port.

Framing error in program

message

A stop bit was not detected when data was received. For example, on a serial port

(for example, a baud rate mismatch).

Input buffer overrun

Software or hardware input buffer on serial port overflows with data caused by

improper or nonexistent pacing.

Query UNTERMINATED

after indefinite response

Indicates that a query was received in the same program message after a query

requesting an indefinite response (e.g., *IDN? or :PTIM:TCOD? or :SYST:STAT?).

A-8

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Command Syntax and Style

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Appendix B Command Syntax and Style

Appendix Contents

This appendix provides an overview of the Standard Commands for

Programming Instrument (SCPI) syntax and style to help you program

the Receiver. A section that lists SCPI reference documentation is also

provided.

This appendix is organized as follows:

• Command Types, Format, and Elements

page B-3

page B-4

page B-7

page B-9

page B-12

–

Command Types

Command Formats

Elements of SCPI Commands

Using Multiple Commands

Elements of Response Messages

• Reference Documentation

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Command Types

There are two types of GPS Receiver programming commands: IEEE

488.2 Common Commands and Standard Commands for

Programmable Instruments (SCPI). The IEEE 488.2 Common

Commands control and manage communications between the

Receiver and the controller, terminal, or personal computer. The SCPI

commands control instrument functions. The format of each type of

command is described in the following paragraphs.

Command Formats

Common Command Format

The IEEE 488.2 Standard defines the Common commands as

commands that perform functions like reset, self-test, status byte

query, and identification. Common commands always begin with the

asterisk (*) character, and may include parameters. The command

keyword is separated from the first parameter by a space character.

Some examples of Common commands are as follows:

*IDN?

*ESE 32

SCPI Command and Query Format

SCPI commands perform functions like instrument setup. A subsystem

command has a hierarchical structure that usually consists of a top

level (or root) keyword, one or more lower-level keywords, and

parameters. The following example shows a command and its

associated query:

:GPS:POSition:SURVey:STATe ONCE

:GPS:POSition:SURVey:STATe?

GPS is a root-level keyword with POSition the second-level keyword,

SURVey the third-level keyword, and STATe the fourth-level. ONCE is

the command parameter.

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Elements of SCPI Commands

A program command or query is composed of functional elements that

include a header (keywords with colon separators), program data, and

terminators. These elements are sent to the Receiver over the serial

interface as a sequence of ASCII characters. Examples of a typical

Common Command and Subsystem Command are:

*CLS

:SYST:ERR?

Common Command Syntax

Figure B-1 shows the simplified syntax of a Common Command.

You must use a space (SP) between the command mnemonic and the

parameter in a Common Command.

mnemonic

parameter

NOTE: sp = space. ASCII character decimal 32

Figure B-1. Simplified Common Command Syntax Diagram

Subsystem Command Syntax

Figure B-2 shows the simplified syntax of a Subsystem Command.

You must use a space (SP) between the last command mnemonic and

the first parameter in a Subsystem Command. Note that if you send

more than one parameter with a single command, you must separate

adjacent parameters with a comma.

mnemonic

parameter

suffix

NOTE: sp = space. ASCII character decimal 32

Figure B-2. Simplified Program Command Syntax Diagram

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Abbreviated Commands

The command syntax shows most keywords as a mixture of upper and

lower case letters. Upper case letters indicate the abbreviated spelling

for the command. For better program readability, you may send the

entire keyword. The Receiver accepts either command form and is not

case sensitive.

For example, if the command syntax shows SYNChronization, then

SYNC and SYNCHRONIZATION are both acceptable forms.

Other forms of SYNChronization, such as SYNCHR or SYNCHRONIZ

will generate an error. You may use upper and/or lower case letters.

Therefore, SYNCHRONIZATION, synchronization, SyNchROnizatioN,

and SYnC are all acceptable.

Keyword Separator

A colon (:) always separates one keyword from the next lower-level

keyword as shown below:

:SYST:ERR?

Parameter Data Types

Table B-1 contains explanations and examples of parameter types.

Parameter types may be numeric value, Boolean, literal, NRf, string,

or non-decimal numeric.

Table B-1. Command and Query Parameter Types

TYPE

EXPLANATIONS AND EXAMPLES

Accepts all commonly used decimal representation of numbers including optional signs,

decimal points, and scientific notation:

123, 123e2, -123, −1.23e2, .123, 1.23e−2, 1.23000E−01.

Special cases include MINimum and MAXimum as follows:

MINimum selects minimum value available.

MAXimum selects maximum value available.

Queries using MINimum or MAXimum return the associated numeric value.

Represents a single binary condition that is either true or false:

1 or ON, 0 or OFF (Query response returns only 1 or 0.)

An <NRf> is rounded to an integer. A non-zero value is interpreted as 1.

Selects from a finite number of choices. These parameters use mnemonics to represent

each valid setting. An example of a <literal> parameter is: GPS

<NRf>

Flexible numeric representation. Only positive integers are used for NRf parameters in

the instrument.

A string parameter is delimited by either single quotes or double quotes. Within the

quotes, any characters in the ASCII B-bit code may be specified.

<non-decimal numeric>

Format for specifying hexadecimal (#H1F), octal (#Q1077), and binary (#B10101011)

numbers using ASCII characters. May be used in :STATus subsystem commands.

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Parameter Separator

If you send more than one parameter with a single command, you must

separate adjacent parameters with a comma.

Query Parameters

All selectable <numeric value> parameters can be queried to return

the minimum or maximum values they are capable of being set to by

sending a MINimum or MAXimum parameter after the “?.”

For example, consider the :GPS:REF:ADEL? query.

If you send the query without specifying a parameter

(:GPS:REF:ADEL?), the present antenna delay value is returned.

If you send the MIN parameter (using :GPS:REF:ADEL? MIN),

the command returns the minimum value currently available. If you

send the MAX parameter, the command returns the maximum value

currently available. Be sure to place a space between the question

mark and the parameter.

Suffixes

A suffix is the combination of suffix elements and multipliers that can

be used to interpret the <numeric value> sent. If a suffix is not

specified, the Receiver assumes that <numeric value> is unscaled

(that is, Volts, seconds, etc.)

For example, the following two commands are equivalent:

:GPS:REF:ADELay 100 NS

:GPS:REF:ADELay 100E-9

Suffix Elements

Suffix elements, such as HZ (Hertz), S (seconds), V (Volts), OHM

(Ohms), PCT (percent), and DEG (degrees) are allowed within this

format.

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Suffix Multipliers

Table B-2 lists the suffix multipliers that can be used with suffix

elements (except PCT and DEG).

Table B-2. Suffix Multipliers

DEFINITION

1E9

MNEMONIC

NAME

GIGA

MEGA

KILO

1E6

MA (or M for OHM and HZ)^*

1E3

1E-3

M (except for OHM and HZ)^*

MILLI

MICRO

NANO

PICO

1E-6

1E-9

1E-12

* The suffix units, MHZ and MOHM, are special cases that should not be confused with

<suffix multiplier>HZ and <suffix multiplier>OHM.

Command Terminator

A command may be terminated with a line feed (ASCII LF character

10 decimal), a carriage return (ASCII CR character 13 decimal), or one

followed immediately by the other in any order.

Using Multiple Commands

Program Messages

Program Messages are a combination of one or more properly

formatted SCPI Commands. Program messages always go from the

DTE to the Receiver. They are sent to the Receiver over the Receiver’s

serial interface as a sequence of ASCII characters.

Program Message Syntax

Figure B-3 shows the simplified syntax of a program message. You can

see Common Commands and Subsystem Commands in the same

program message. If you send more than one command in one message,

you must separate adjacent commands with a semicolon.

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

;

Subsystem Command

Common Command

NOTE:

<new line> = ASCII character decimal 10

<carriage return> = ASCII character decimal 13

Figure B-3. Simplified Program Message Syntax Diagram

When using IEEE 488.2 Common commands with SCPI Subsystem

commands on the same line, use a semicolon between adjacent

commands. For example:

*CLS;:SYST:ERR?

When multiple SCPI Subsystem commands are sent in one program

message, the first command is always referenced to the root node.

Subsequent commands, separated by “;”, are referenced to the same

level as the preceding command if no “:” is present immediately after

the command separator (the semicolon).

For example, sending

:GPS:INIT:DATE 1994,7,4;TIME 12,34,56

is equivalent to sending:

:GPS:INIT:DATE 1994,7,4

:GPS:INIT:TIME 12,34,56

:GPS:INIT:DATE 1994,7,4;:GPS:INIT:TIME 12,34,56

The “:” must be present to distinguish another root level command.

For example:

:SYNC:HOLD:DUR?;:GPS:SAT:VIS:PRED?

is equivalent to sending:

:SYNC:HOLD:DUR?

:GPS:SAT:VIS:PRED?

B-8

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

If the “:”(which is following the “;” and is in front of GPS) is omitted,

the Receiver assumes that the second command is

:SYNC:HOLD:GPS:SAT:VIS:PRED?

and generates a syntax error.

Elements of Response Messages

Response Messages

Response messages are data sent from the Receiver to the DTE in

response to a query. (A query is a command followed by a question

mark. Queries are used to find out how the Receiver is currently

configured and to transfer data from the Receiver to the DTE.)

After receiving a query, the Receiver interrogates the requested

configuration and issues its response message as soon as possible.

The message is transmitted across the serial interface to the DTE.

Response Message Syntax

Figure B-4 shows the simplified syntax of a Response Message.

Response messages may contain both commas and semicolon

separators. When a single query command returns multiple values,

a comma is used to separate each item. When multiple queries are sent

in the same program message, the groups of data corresponding to

each query are separated by a semicolon.

;

response data

NOTE:

<new line> = ASCII character decimal 10

<carriage return> = ASCII character decimal 13

; = multiple response separator (ASCII character decimal 59)

, = data separator within a response (ASCII character decimal 44)

Figure B-4. Simplified Response Message Syntax Diagram

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Response Formats

Table B-3 contains explanations of response formats.

Table B-3. Response Formats

Format

Description

This numeric format represents an integer (e.g., +9).

<digit>

−

The maximum number of characters in dd response data is 17 (maximum

16 digits, 1 sign).

dd, ...

This numeric format represents a comma-separated list of integers

(e.g., +1,+2,+3).

d.d

This numeric format represents a fixed (e.g., +10.5).

<digit>

−

d.dEe

This numeric format represents a floating-point number (e.g., +1.00E+000).

<digit>

−

<digit>

The maximum number of characters in d.dEe response data is 13 (maximum

6 mantissa digits, 2 signs, 1 decimal point, 1 'E' character, 3 exponent digits).

d.dEe,

This numeric format represents comma-separated list of floating-numbers

(e.g., +1.00000E-009, +2.00000E-009, +5.00000E-009).

0 or 1

A single ASCII-encoded byte, 0 or 1, is returned for the query of settings that

use ON, OFF, 1, or 0 parameters.

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Appendix B Command Syntax and Style

Command Types, Format, and Elements

Table B-3. Response Formats (Continued)

Format

XYZ

Description

ASCII-encoded bytes corresponding to the literal used as the command

parameter.

alpha

digit

An example of an alphanumeric response is: NONE

“XYZ ”

A string response consists of ASCII characters enclosed by double quotes.

For example, string data is used for the “<error description>” portion of

:SYST:ERR? response.

“XYZ”, ...

A list of string responses consist of comma-separated ASCII characters

enclosed by double quotes.

(e.g., “log 224:19951017.00:00:26:30: Holdover started, GPS”,

“log 225:19951017.00:00:29:02: GPS lock started”)

ASCII Data

Binary Data

A sequence of ASCII-encoded bytes.

The syntax is a pound sign (#) followed by a non-zero digit representing the

number of digits in the subsequent decimal integer. The decimal integer

specifies the number of 8-bit data bytes being sent. This is followed by the

actual data. The terminator is a line feed. For example, for transmitting 8 bytes

of data, the format might be:

Number of digits

that follow

Actual data

Terminator

#208<8 bytes of data><carriage return><new line>

Number of bytes

to be transmitted

The “2” indicates the number of digits that follow and the two digits “08” indicate

the number of data bytes to be transmitted.

<carriage return> is defined as a single ASCII-encoded byte corresponding to

13 decimal.

<new line> is defined as a single ASCII-encoded byte corresponding to

10 decimal.

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Appendix B Command Syntax and Style

Reference Documentation

This section contains a list of documentation related to the use of the

Receiver’s RS-232C serial port. Additional information that you may

find useful can be found in the following publications:

1. Beginner’s Guide to SCPI (HP Part Number H2325-90001,

July 1990 Edition).

2. Beginner’s Guide to SCPI, Barry Eppler (Hewlett-Packard

Press, Addison-Wesley Publishing Co. 1991).

3. Standard Commands for Programmable Instruments

(SCPI), Version 1992.0.

This standard is a guide for the selection of messages to be included

in programmable instrumentation. It is primarily intended for

instrument firmware engineers. However, you may find it useful if

you are programming more than one instrument that claims

conformance to the SCPI standard. You can verify the use of

standard SCPI commands in different instruments.

To obtain a copy of this standard, contact:

SCPI Consortium

8380 Hercules, Suite P3

La Mesa, CA 91942

Phone: (619) 697-8790

FAX: (619) 697-5955

4. The International Institute of Electrical Engineers and

Electronic Engineers, IEEE Standard 488.2-1987, IEEE

Standard Codes, Formats, Protocols, and Common

Commands for Use with ANSI/IEEE Std 488.1-1987

Programmable Instrumentation.

This standard defines the underlying message formats and data

types used in SCPI. It is intended more for firmware engineers

than for instrument users/programmers. However, it can be useful

if you need to know the precise definition of specific message

formats, data type, or common commands.

To obtain a copy of this standard, write to:

The Institute of Electrical and Electronic Engineers Inc.

345 East 47th Street

New York, NY 10017 USA

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Appendix C Receiver Firmware Installation

Downloading New Firmware Using SatStat Program

Downloading New Firmware Using

SatStat Program

1 Copy the file of the updated firmware disk to a directory on your PC

disk drive.

If you haven’t already installed SatStat, you should install it now

(follow instructions on the disk label or in the section titled “To Install

the Automated SatStat Program for Continual Status Updates” in

Chapter 3, “Visual User Interface,” of this guide).

2 Start SatStat (easiest way is to double-click on the icon).

3 You should establish communication with the GPS Receiver.

This requires connection from a serial RS-232 port on your PC to the

GPS Receiver’s serial port (a 25-pin RS-232 connection). Assuming

you’ve got the cable attached to make this connection, you may want to

check the settings.

a. Select CommPort, then choose Settings.

The Communication Settings dialog box is displayed. Unless

someone has reprogrammed the CommPort settings on the GPS

Receiver, these settings are probably OK. The one setting that is

likely to need changing is the Com Port. The application defaults it

to Com1, but the serial port on your PC may be assigned to a

different Com Port. Select the appropriate setting. If you are unsure,

Com1 will be your best bet (worst case, you can cycle through all of

them until it works).

b. If you made any changes on this form, select OK, otherwise you can

just Cancel.

4 Select CommPort, then choose Port Open.

The main form of the Receiver Status screen is displayed.

The application will send some commands to the GPS Receiver and

then the main form should begin to periodically update every few

seconds. If you are getting screen updates, proceed to the next step.

Otherwise, something is wrong with your CommPort settings or

perhaps the physical connection between your PC and the GPS

Receiver.

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Appendix C Receiver Firmware Installation

Downloading New Firmware Using SatStat Program

NOTE

Prior to download, interrogate the product, record any custom

configuration parameters. This step is necessary because

downloading new instrument firmware will reset all

parameters to system-preset defaults. Parameters typically

recorded include:

• antenna delay

• elevation mask angle

• timezone offset

A table of all system-preset defaults is printed in Table 5-2 on

page 5-111 in Chapter 5 of this guide; refer to it to identify

additional parameters whose default values are inappropriate

for your application. Record the settings you use prior to

download.

5 Performing the download works best if the periodic updates are

disabled. On the main form, select the Function menu, choose Status

(check mark appears), and choose Disable Updates (check mark

appears).

6 Activate the form titled “Control & Query” by clicking anywhere on it.

Select Service, then choose Download Firmware. This will bring up a

form titled “Firmware Download”.

7 Now you need to select the file that you will download. Select the

control labeled File.

This brings up a form for file selection. Download files for the GPS

Receiver have a .s appended to the file name. This form is set to only

find .s type files. In this case, you want to find and select the filename,

for example s_3503.s. Depending on where you have placed this file,

you may have to use this form to navigate for it. If it is on a different

drive, use the Drives selection in the lower right. Once you’ve located

s_3503.s select it (clicking on the name is probably the easiest) and

then select OK. The file, along with its path should now appear in the

“File to Download” portion of the “Firmware Download” form.

8 You’re now ready to perform the download. Select the control titled

Download and an erase warning will appear. This is just a

double-check to make sure you really want to do this. Assuming you do,

select Yes, Perform the Download.

The program will switch the GPS Receiver to the “INSTALL” language,

erase the flash memory, and begin downloading S-records. The

S-records are the long character strings that appear in the lower part

of the form as the downloading process proceeds. The total

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Appendix C Receiver Firmware Installation

Downloading New Firmware Using SatStat Program

downloading time varies depending on the type of PC you have, but

with communication settings optimized a typical time is about

30 minutes. Once the download is under way, an estimate of the time

to complete the process is updated every 100 S-records.

9 When the downloading has completed, the “Minutes Until Finished”

field will say “DONE”. You can then select Close on the Firmware

Download form.

There are a couple of ways to confirm that the new firmware has been

installed; the easiest is to just power-cycle the unit. Once it has

powered up, you can confirm that the new revision is in place by

selecting Query, then choosing Product ID (from the “Control & Query”

form) and selecting Send Cmd. The product ID will appear on the

Control & Query form and should contain the new date code “3503”,

for example. An alternative way to check the download is to type

SYST:LANG "PRIMARY" in the edit field on the “Control & Query”

form and select Send Cmd. This will return the unit to normal

operating mode without power-cycling. If you do this, you could then

check the product ID as described above. NOTE: it is expected that in

early software revisions the alarm will come on the first time you

power-cycle (or switch to “primary” using SYST:LANG “PRIMARY”).

If you investigate the alarm, you will find it is the software

safeguard—it has gone off because you have changed the instrument

firmware. On subsequent power-ons the alarm will not come on.

After upgrading instrument firmware, you will need to restore the

instrument settings recorded prior to the download, and restore the

instrument and PC communications settings so that BAUD rate and

echo are set according to the requirements of your installation.

C-4

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Performance Tests

Verifying Specifications

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Appendix D Performance Tests

Introduction

This appendix provides procedures to test the electrical performance of

the 58503B and 59551A GPS Receivers specifications listed in and

Appendix E, “58503B Specifications,” and Appendix F, “59551A

Specifications,” of the. Two types of testing are provided:

• Operational Verification, starting on page D-5

• Complete Performance Tests, starting on page D-17

Operational Verification

The Operational Verification operational verification test is an

abbreviated series of checks that may be performed to give a high

degree of confidence that the instrument is operating properly without

performing the Complete Performance Tests. An operational

verification is useful for incoming inspection, routine maintenance, and

after instrument repair.

Complete Performance Tests

The Complete Performance Tests performance tests verify the

specifications listed in Appendix E, “58503B Specifications or

Appendix F, “59551A Specifications.” All tests can be performed

without access to the inside of the instrument.

Test Record

The results of the Operational Verification and Complete Performance

Tests should be recorded on a copy of the appropriate (i.e., 58503B or

59551A) Performance Test Record, located at the end of this chapter.

D-2

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Appendix D Performance Tests

Equipment Required

Table D-1. Recommended Test Equipment

Instrument

Required Characteristics

Recommended Model

Use*

Digitizing

Oscilloscope

2 channels

500 MHz bandwidth (repetitive)

HP 54600B (or

equivalent)

OV, P

Digital Multimeter

(DMM)

Microvolt accuracy with leads

HP 34401A (or

equivalent)

OV, P

Terminal or

computer

Communication Software, RS-232C

connection

Any Model

Universal Counter

Resolution: 300 ps or better in T.I.

Mode

HP 53132A (or

equivalent)

Frequency Standard 1 PPS Source. Jitter: <1 ns rms

pulse-to-pulse

HP 5071A (or equivalent)

10 MHz House Standard. Accuracy:

2X10^-12or better

50Ω Feedthrough

____________________________

HP 10100C (or

equivalent)

50Ω Coaxial Cable

BNC(m) to BNC(m), 48 inches

____________________________

HP 10503A (or

equivalent)

with BNC connectors

GPS Antenna or

Antenna Assembly

58504A or 58513A

58518A, 58520A

58519A, 8521A

GPS Antenna Cable

Assembly

RG-213 or LMR 400 cables with

TNC (m)-to-N (m) connectors

Antenna

Interconnect Cable

Assembly

RG-213 or LMR 400 cables with

N (m)-to-N (m) connectors

Barrel adapter

N (f)-to-N (f)

HP 1250-0777 (or

equivalent)

*OV = Operational Verification

P = Performance Tests

T = Troubleshooting

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Appendix D Performance Tests

Before You Start

The time required to acquire lock as described in the following section

can vary significantly depending on your local conditions. In general, it

is strongly recommended that your antenna and cables be set up in

accordance with the information provided in the documents listed

below prior to performing any of the tests that follow, or the results

cannot be assumed to be valid.

Documents providing GPS Antenna System information are:

• Designing Your GPS Antenna System Configuration Guide

configuration guide, which discusses the components of an

GPS timing receiver system and how to custom design the

configuration of your antenna system. Contact your local Sales

office for a copy of this guide.

• Information Notes that provide installation procedures for the

applicable GPS antenna and accessories that you purchase.

Acquiring lock does not mean that the unit is fully operational and

meeting specifications. It just means that the GPS Receiver has

detected enough satellites to start its survey mode to determine its

precise location. An Internal measurement FFOM (Frequency Figure

of Merit) becomes 0 when the internal loops reach their proper time

constants, indicating that the output frequency and 1 PPS signals are

now fully operational and meeting their specifications. Under the

worst conditions, the GPS Receiver may take 24 to 72 hours to achieve

FFOM = 0. FFOM can be monitored in the Reference Outputs

quadrant of the Receiver Status screen (see the sample status screen,

Figure 3-1, in Chapter 3, “Visual User Interface,” of this guide if

needed). Also, using :PTIMe:TCODe? query command will provide the

FFOM value.

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Appendix D Performance Tests

Operational Verification

Introduction

The 58503B and 59551A GPS Receivers are designed to automatically

detect and acquire satellites in order to begin providing precise

frequency and time information.

Until such acquisition is complete and the unit is locked with

FFOM = 0, the signals produced on the rear panel are not precise.

However, it is possible to verify that the Receiver has been received in

good working condition by performing some simple operational

verification tests upon receipt.

Except for two tests (Time Stamp Verification and Programmable

Pulse Verification), all of the following operational verification tests do

not require usage of the GPS antenna. These tests are designed to

provide a high degree of confidence that the Receiver is functioning,

but the tests will not verify the specified performance characteristics.

Such testing requires more expensive equipment and very long test

times (over 72 hours per unit). We recommend that full or complete

Performance Testing be restricted to testing only after any repairs to

the 58503B or 59551A.

The 58503B and 59551A require no calibration.

Record the results of the Operational Verification in the

appropriate place on the appropriate (i.e., 58503B or 59551A)

Performance Test Record, which is located at the end of this

chapter.

Power-Up Procedure

NOTE

Use the HP 10100C 50Ω feedthrough on the input of the oscilloscope

for the following test.

1 Connect the Receiver to a suitable power source. The unit will perform

a self-test of internal components.

2 Verify that after 15 seconds the Power indicator is on and the Alarm

indicator is off. This ensures that all internal components and

connections are functioning. (If needed, refer to the subsection titled

“To Connect Power” in Chapter 1 of the 58503B/59551A Getting

Started Guide for assistance in connecting the Receiver to a power

source.)

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Appendix D Performance Tests

Operational Verification

10 MHz Verification (58503B Only)

1 Set the HP 54600B oscilloscope or equivalent sweep rate to 100 ns/div,

input amplitude to 0.2 Volts/div, and input coupling to ac.

2 Connect the oscilloscope to the rear-panel 10 MHz OUT output of the

58503B as shown in Figure 2.

HP 54600B

Oscilloscope or equivalent

58503B

GPS Receiver

(Rear Panel)

ANT

10 MHz

50Ω Feedthrough

(HP 10100C)

BNC Cable

Figure D-1. 58503B 10 MHz Operational Verification Setup

3 Verify that there is a 10 MHz sine wave present with approximately

1 Volt peak-to-peak into the 50 ohm load.

4 Mark Pass or Fail in Line 1 on the Operational Verification portion of

the 58503B Performance Test Record, located at the end of this

chapter.

1 PPS Verification

1 Set the oscilloscope sweep rate to 5 µs/div, input amplitude to 5 Volts,

and input coupling to dc.

2 Connect the oscilloscope to the rear-panel 1 PPS output of the Receiver

as shown in Figure D-2.

D-6

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Appendix D Performance Tests

Operational Verification

HP 54600B

Oscilloscope or equivalent

58503B

GPS Receiver

(Rear Panel)

ANT

1PPS

50Ω Feedthrough

(HP 10100C)

BNC Cable

1PPS

59551A

GPS Receiver

(Rear Panel)

Figure D-2. 1 PPS Operational Verification Setup

3 Verify the presence of a TTL level pulse with approximately 20 ^µs pulse

width.

4 Mark Pass or Fail in Line 2 on the Operational Verification portion of

the appropriate ( 58503B or 59551A) Performance Test Record, located

at the end of this chapter.

IRIG-B Verification (59551A Only)

1 Set the oscilloscope sweep rate to 1 msec/div and input amplitude to

5 Volts/div, dc-coupled.

2 Connect the oscilloscope to the rear-panel IRIG-B output of the 59551A

GPS Receiver as shown in Figure 2.

Verify that the display shows a sine wave with a period of 1 ms,

changing in amplitude from 5 Volts peak-to-peak, to greater than

10 Volts peak-to-peak. This is the IRIG-B time code modulating a

1 kHz carrier.

3 Mark Pass or Fail in Line 3 on the Operational Verification portion of

the 59551A Performance Test Record, located at the end of this

chapter.

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Appendix D Performance Tests

Operational Verification

HP 54600B

Oscilloscope or equivalent

59551A

GPS Receiver

(Rear Panel)

IRIG-B

50Ω Feedthrough

(HP 10100C or equivalent)

BNC Cable

Figure D-3. 59551A IRIG-B Operational Verification Setup

Time of Day and PORT 1 RS-232C Serial Interface

Verification

1 Connect a terminal or computer (set to 9600 baud, 8 data bits, 1 stop

bit, and no parity and no pace) to the rear-panel PORT 1. If you need

assistance in setting the serial parameters, refer to the Getting Started

guide.

2 Press the Return key on the terminal.

Verify that either a SCPI > or E-xxx> prompt is returned. The xxx can

be any number for this test. If E-xxx> is returned, send the *CLS

command to clear the error.

3 Type :SYSTEM:STATUS?, then press Enter (or Return) key.

The terminal screen displays the Receiver Status screen, which is a

complete status report of the Receiver. Without a GPS antenna, most

data will be blank or indicating that the instrument is in “Power-Up”

mode. The FFOM = 3 in the upper right corner indicates that the

Receiver is in power-up mode and frequency outputs are invalid. At

this point, the data at the bottom of the screen lists the results of all

internal self-tests. The HEALTH MONITOR, SelfTest, Int Pwr,

Oven Pwr, OCXO, EFC, and GPS Rcv should all show OK.

4 From the terminal keyboard, type

:PTIME:TCODE? and press Return.

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Appendix D Performance Tests

Operational Verification

An alphanumeric string which starts with a “T” should be displayed as

shown in the following example:

T2199505112055233000049

Note that the value above will be different for each test, depending on

the local date and time.

5 Mark Pass or Fail in Line 4 on the Operational Verification portion of

the appropriate (58503B or 59551A) Performance Test Record, located

at the end of this chapter.

Antenna Power Verification

1 Set the DMM to read a range of 5 Volts dc.

2 Measure the dc voltage from the center pin of the antenna (Type N)

connector with respect to the threaded connector shell.

Verify that the voltage is between 4.5 and 5.0 Volts dc.

3 Mark Pass or Fail in Line 5 on the Operational Verification portion of

the appropriate (58503B or 59551A) Performance Test Record, located

at the end of this chapter.

4 If you are testing the 58503B with Option 001 Front Panel and

Keypad, perform the procedure in the following section titled “Front

Panel Display/Keypad Verification (58503B Option 001 Only)” on

page D-10.

If you are testing the standard 58503B, go to the section titled

“Operational Verification Conclusion” on page D-15 in this chapter.

If you are testing a 59551A, go to the section titled “Time Tagging

(Stamping) Verification and Programmable Verification (59551A

Only)” on page D-11.

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Appendix D Performance Tests

Operational Verification

Front Panel Display/Keypad Verification (58503B

Option 001 Only)

This tests the operation of the Front Panel Display/Keypad option for

the 58503B.

1 Disconnect and re-apply power to the 58503B.

2 While the letters "HP" are moving from right to left (about 2 seconds),

press Sat key and then Time key to enter the TEST/DEMO mode.

3 The words VFD DSP TEST will momentarily appear.

The display should then show a test pattern that sequentially

illuminates all 15 segments of all digits and punctuation marks in the

display.

4 Verify that all segments illuminate.

5 When the segment illumination sequence is complete, the words

DEMO MODE should then appear.

6 Press each key one at a time. Each keypress should:

• illuminate the LED corresponding to that key, and

• display a simulated response to the function.

NOTE

(1) The Clear Alarm (Shift , Alt) function will exit the test. (2) The

values displayed are not related to the 58503B under test. They are

displayed for demonstration only.

7 To exit the diagnostic, press Shift key, and then press Alt key.

8 The 58503B power-up sequence should then continue. No further tests

are necessary.

9 Mark Pass or Fail in Line 5 on the Operational Verification portion of

the 58503B Performance Test Record, located at the end of this

chapter.

10 Proceed to the section titled“Operational Verification Conclusion” on

page D-15 to complete the operational verification.

D-10

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Appendix D Performance Tests

Operational Verification

Time Tagging (Stamping) Verification and

Programmable Verification (59551A Only)

NOTE

GPS ANTENNA REQUIRED. The steps below require that a GPS

antenna be properly set up, and the 59551A is in GPS locked mode

before proceeding. For information on how to make such a setup, refer

to the antenna information provided on page D-4 in this chapter.

If you determine that these tests will not be performed for your facility,

please proceed to the next section titled “Operational Verification

Conclusion” on page D-15.

1 Connect a GPS Antenna and cable to the 59551A and allow the

Receiver to indicate it is in “GPS Lock” mode as indicated by the

illuminated GPS Lock indicator. Until GPS lock is attained, the

following tests will not be valid. Your test setup should be similar to

Figure 1.

GPS

Antenna

Terminal or Computer

59551A

GPS Receiver

(Rear Panel)

Figure D-4. 59551A Time Tagging Operational Verification Setup

2 Enter the following commands from the terminal or computer to note

the current date and time.

:PTIME:DATE?

:PTIME:TIME?

3 On the computer or terminal, type :SENSE:DATA:CLEAR and press the

Return key.

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Appendix D Performance Tests

Operational Verification

This clears the Time Tagging event registers of any data prior to the

next step.

4 On the computer or terminal, type :FORMAT:DATA ASCII and press the

Return key.

This sets the output format of the Time Tagging Data to an ASCII

string for easier interpretation.

5 Refer to Chapter 2, “Features and Functions,” in the 58503B/59951A

Getting Started Guide to identify types of stimulus equipment that

could be used for this test.

A suggested general-purpose device could be a pulse generator, set to

output a TTL level pulse.

6 Use this signal to send an event to each of the three Time Tagging

inputs.

7 From the terminal or computer, send the following query commands to

verify that an event was recorded in each of the Time Tagging event

registers. Note that there is a space between the question mark (?) and

the quotation mark (“) in the following commands.

:SENSE:DATA? “TSTAMP 1”

:SENSE:DATA? “TSTAMP 2”

:SENSE:DATA? “TSTAMP 3”

Note that the actual date and time of the record is not being tested.

8 Verify that each response is the following format:

yyyy,mm,dd,hh,mm,ssssssss,xxxxxxxxxx

9 On the terminal, type :SENSE:DATA:CLEAR and press the Return key.

10 This again clears the Time Tagging event registers of any data from

this test.

11 Mark Pass or Fail in Line 6 on the Operational Verification portion of

the 59551A Performance Test Record, located at the end of this

chapter.

D-12

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Appendix D Performance Tests

Operational Verification

Programmable Pulse Verification (59551A Only)

1 Enter the following commands from the terminal or computer:

:PULSE:CONTINUOUS:PERIOD 1

This sets the period to 1 second.

:PULSE:CONTINUOUS:STATE ON

This sets the programmable pulse output to provide a continuous

stream of pulses.

:PULSE:START:DATE <four-digit year>, <month>, <day>

2 Set the year, month, and day to the same values read in step 2 in the

previous procedure “Time Tagging Verification.”

Example:

:PULSE:START:DATE 1995, 7, 25 is July 25, 1995.

:PULSE:START:TIME <hours>, <minutes>, <seconds>

3 Set the hours, minutes, and seconds to the same values observed in

step 2 of the previous procedure “Time Tagging Verification.”

Example:

:PULSE:START:TIME 13, 1, 5 is 13:01:05 in 24-hour format.

NOTE

Setting the time to a value earlier than the present time will start the

pulse stream immediately. If a time is input with a value some time in

the future, the pulse stream will not start until that time is attained.

4 Set the oscilloscope sweep rate to 5 msec/div, input amplitude to

5 Volts/div, and input coupling to dc.

5 Connect the oscilloscope to the rear-panel Programmable Pulse output

as shown in Figure 5.

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Appendix D Performance Tests

Operational Verification

GPS

Antenna

HP 54600B

Oscilloscope or equivalent

Programmable Pulse

50Ω Feedthrough

59551A

GPS Receiver

(HP 10100C)

BNC Cable

(Rear Panel)

Terminal or Computer

Figure D-5. 59551A Programmable Pulse Operational Verification

Setup

6 Verify that a continuous stream of TTL-compatible pulses are

occurring at a 1 second rate.

7 Mark Pass or Fail in Line 7 on the Operational Verification portion of

the 59551A Performance Test Record, located at the end of this

chapter.

D-14

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Appendix D Performance Tests

Operational Verification

Operational Verification Conclusion

NOTE

Perform the following step only if you wish to restore memory of the

58503B or 59551A Receiver to the factory default states. Doing this can

change several parameters that have been stored by a previous user. If

you have any questions or concerns, refer to Table 5-2 under the

description of the :SYSTEM:PRESET command on page 5-111 of

Chapter 5 in this guide for information on the type of information that

is stored.

On the terminal or computer, type:

:SYSTEM:PRESET and press the Return key.

This will ensure that your Receiver has been restored to the factory

defaults as originally received.

This completes the operational verification.

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In Case of Difficulty

If any of the above tests fail it should be re-checked before assuming

that the unit is defective. Return any defective unit.

D-16

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Appendix D Performance Tests

Complete Performance Tests

The specifications of the 58503B and 59551A can be verified by

performing the Performance Tests provided in this section. Table D-2

lists a summary of the 58503B/59551A Complete Performance Tests.

Table D-2. The 58503B/59551A Complete Performance Tests

Page

Time and Frequency Output Tests

Number

D-18

D-19

Preliminary Test Setup

Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter

(Locked to GPS)

D-22

Test 2: 10 MHz Holdover Aging and 1 PPS Accumulated

Time Error (Unlocked)

D-24

Test 3: 1 PPS Time Accuracy (Locked)

Test 4: 10 MHz Frequency Stability (Time Domain) and

Phase Noise (Frequency Domain) Measurements

The following tests will ensure that the 58503B GPS Time and

Frequency Reference Receiver and 59551A GPS Measurements

Synchronization Module are meeting the published specifications.

Some of these tests will require that the Receiver be operating

continuously for at least 3 days, others require that the Receiver be

disconnected from GPS, and others will require further investigation in

order to produce a satisfactory setup and measurement.

The critical specifications to be tested are the 10 MHz Frequency

Accuracy (1 day) and the 1 PPS Jitter (1 day) specifications. As long as

the Receiver is locked, the proper performance of these two

specifications will imply that the other specifications are in

conformance.

The following tests do not test “typical” or “nominal” specifications, or

“supplemental characteristics,” “supplemental information,” or

“features.”

Record the results of the Performance Test in the appropriate

place on the appropriate (i.e., 58503B or 59551A) Performance

Test Record, which is located at the end of this chapter.

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Appendix D Performance Tests

Complete Performance Tests

Preliminary Test Setup

If you have not connected the GPS antenna to the Receiver, perform

the following preliminary procedure in this section.

If you have already connected the GPS antenna to the Receiver, go to

the next subsection titled “Test 1: 10 MHz Frequency Accuracy and

1 PPS Jitter (Locked to GPS).”

1 Connect the antenna system to the rear-panel ANTENNA Type-N

connector of the Receiver as described in the instructions given in the

section titled “Preparing the GPS Receiver for Use” in Chapter 1, of the

58503B/59551A Getting Started Guide.

NOTE

Do not apply power to the Receiver unless a fully operational antenna

system is connected to the ANTENNA input connector. Power applied

with no antenna input or a non-functioning antenna will initiate an

extended search process that may increase time to reach GPS lock. You

can halt the extended search by disconnecting and reconnecting

(cycling) the external supply voltage to the Receiver (you may need to

leave power disconnected for greater than five seconds).

2 Connect the Receiver to a suitable power source. (If needed, refer to the

subsection titled “To Connect Power” in Chapter 1 of the

58503B/59551A Getting Started Guide.)

3 The Receiver will perform a self-test of internal components. Verify

that after 15 seconds the Power indicator illuminates and the Alarm

indicator is off. This ensures that all internal components and

connections are functioning.

D-18

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Appendix D Performance Tests

Complete Performance Tests

Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter

(Locked to GPS)

This test measures the relative change in the 1 PPS pulses between

the unit under test and a known accurate source. A time interval is

measured and the data is stored to be compared with a second

measurement, 24 hours later. The 1 PPS source is derived from the

internal 10 MHz, and the relative accuracy of 1 PPS is directly related

to the accuracy of the 10 MHz.

Specifications Tested

-12

Frequency Accuracy (locked): Better than 1 x 10 for a one day

average, 0 degrees to 50 degrees C.

1 PPS Jitter of leading edge: <750 ps with at least one satellite in

view, Selective Availability on.

Procedure

1 Connect the terminal or computer to the Receiver using the cable

recommended in the Getting Started Guide and ensure that they are

both communicating.

2 Ensure that the Receiver is in “GPS Lock” mode as indicated by the

illuminated GPS Lock indicator, and that FFOM = 0. The current

value of FFOM and many other characteristics of the unit can be

determined by typing :SYSTEM:STATUS? on the terminal.

3 Connect the 10 MHz reference output from the reference 1 PPS source

(HP 5071A or another stable, traceable house standard) to the

rear-panel Ref In of the Universal Counter, as shown in Figure D-6, to

provide an external timebase for the Counter.

GPS

Antenna

Ref. In (rear panel)

50Ω Feedthrough (HP 10100C)

Port1

58503B or

59551A

10 MHz External

HP 53132A

Reference Out

(rear panel)

1PPS

(rear panel)

Universal

Counter

GPS Receiver

(Rear Panel)

or equivalent

5071A

PRIMARY FREQUENCY STANDARD

Continuous

Operation

ANT

1PPS

Output

Channel 1

Channel 2

HP 5071A

Primary Frequency Standard or

House Standard

Figure D-6. 10 MHz Frequency Accuracy and 1 PPS Jitter Test Setup

(58503B GPS Receiver shown)

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4 Connect the rear-panel 1 PPS from Receiver under test to Channel 1 of

the Universal Counter.

5 Connect the 1 PPS from the reference standard (5071A) to Channel 2.

6 On the terminal or computer, enter the following command to clear all

entries in the Diagnostic (status) Log:

:DIAG:LOG:CLEAR and press the Enter (or Return) key.

7 Set the Universal Counter function to take 100 samples of Time

Interval and compute the Mean value. Ensure that the inputs are set

to DC-coupled, 50 Ohms, and rising edge. Set the trigger level for both

inputs to 1Volt dc.

8 Record the average time interval for later comparison.

_______________________________________ seconds.

9 Disconnect the reference 1 PPS from input 2 and set the counter to

“COMMON” mode so the 1 PPS from the Receiver is input to both

channels. For this step, be sure the trigger levels are both set to 1 Volt

dc.

10 Set the counter to compute the Standard Deviation for the same 100

samples.

This is the RMS Jitter of the 1 PPS.

D-20

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11 Again, allow the counter to accumulate 100 samples of time interval.

12 Note the largest deviation (greater or less) from exactly 1 second.

This the worst-case 1 PPS leading edge jitter.

13 Record the results of 1 PPS Jitter on Line 2 of Test 1 of the

Performance Test Record.

14 Wait 24 hours to complete the Frequency Accuracy test.

15 On the terminal or computer, enter the following command:

:DIAG:LOG:READ:ALL? and press the Enter (or Return) key.

Observe the messages (if any) that appear and verify that none of the

messages indicate that the 58503B/59551A has entered holdover mode.

If it has, the entire test must be re-started from step 2 above.

16 Repeat steps 2 through 8 above after the 24-hour period.

17 Compute the Frequency Accuracy using the following formula:

(t1 – t2)seconds

---------------------------------------------= Accuracy (unitless)

∆tseconds

Where,

t1 is the average time interval first measured

t2 is the average time interval last measured

∆t is the time between measurements (86,400 seconds = 24 hours)

18 Record the results of Frequency Accuracy in Line 1 of Test 1 of the

Performance Test Record.

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Appendix D Performance Tests

Complete Performance Tests

Test 2: 10 MHz Holdover Aging and 1 PPS

Accumulated Time Error (Unlocked)

The following tests are identical to the previous tests, with the

exception that during the actual test, the Receiver is not locked to the

GPS. However, the test must adhere to the restrictions noted below

with the specification in order for the results to be valid.

Specifications Tested

-10

Holdover aging: < 1 x 10 /day average frequency change in 24 hours

unlocked after 3 days locked operation for any 10 degrees C range

between 10 degrees C and 40 degrees C.

Accumulated time error: <8.6 us accumulated in 24 hours unlocked

after 3 days of locked operation with a fixed antenna location, any

10 degrees C range between 10 degrees and 40 degrees C.

Procedure

1 Ensure that the Receiver has been in GPS Lock mode for at least three

(3) days without entering holdover mode by typing the following

command on the terminal or computer:

:DIAG:LOG:READ:ALL? and press the Enter (or Return) key.

Verify that there are no messages to indicate that holdover mode was

started during the last 72 hours of operation.

2 Ensure that the temperature restrictions described above will be met

for the next 24 hours.

3 Connect the 10 MHz reference output from the reference 1 PPS source

(5071A or another stable, traceable house standard) to the rear-panel

Ref In of the Universal Counter, as shown in Figure D-6, to provide an

external timebase for the Counter.

4 Connect the rear-panel 1 PPS from Receiver under test to Channel 1 of

the Universal Counter.

5 Connect the 1 PPS from the reference standard (5071A) to Channel 2.

Ensure that the inputs are set to DC-coupled, 50 Ohms, and rising

edge. Set the trigger level for both inputs to 1 Volt dc.

6 Disconnect the antenna cable (N-type connector) at the rear of the

Receiver to force it into Holdover Mode.

7 Ensure that the Holdover indicator is illuminated and the GPS Lock is

not illuminated.

D-22

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8 Note the time interval average for 100 samples, either positive or

negative.

NOTE

Do not re-connect the antenna at this time. It must remain

disconnected for the entire 24-hour period.

9 Wait 24 hours to complete the Holdover Aging test. During this

24-hour period, ensure that the temperature restrictions are

maintained. If the temperature does exceed the range, the Receiver

will have to be re-connected to the antenna, allowed to lock, run for at

least 3 days, and re-tested with this procedure.

10 Repeat steps 3, 4, 5, and 8 above after the 24 hour period.

11 If desired, re-connect the antenna cable at this time.

12 Compute the Holdover Aging rate using the following formula:

(t1 – t2)seconds

---------------------------------------------= Aging rate (unitless)

∆tseconds

Where,

t1 is the average time interval first measured

t2 is theaverage time interval last measured

∆t is the time between measurements (86,400 seconds = 24 hours)

13 Compute the Accumulated Time Error using the following formula:

(t1 - t2) seconds = Error (seconds)

Where t1 and t2 are defined as in the previous step.

14 Record the results of Holdover Aging and 1 PPS Accumulated Time

Error in the Test 2 row of the Performance Test Record.

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Complete Performance Tests

Test 3: 1 PPS Time Accuracy (Locked)

This specification is a statistical probability that the Receiver will

conform to the standard as described. This cannot be tested with any

degree of confidence except at NIST or an equivalent National

Standards Laboratory. Actual accuracy obtained depends on the exact

knowledge of the geophysical location, characteristics and delay in the

antenna, calibration of all measurement delays, and calibration of

antenna cable delay. Calibration of both ionospheric and tropospheric

delay use the standard algorithms provided in the GPS data messages.

At the 95% confidence level, time errors associated with the Receiver,

GPS system, and ionospheric and tropospheric effects will be less than

110 ns.

Test 4: 10 MHz Frequency Stability (Time Domain)

and Phase Noise (Frequency Domain) Measurements

NOTE

High accuracy precision measurements of both time and frequency

domain stability are available through the National Institute of

Standards and Technology (NIST) in the USA, and at other equivalent

National Standards Laboratories. NIST can completely characterize

and verify all major specifications of the 58503B or 59551A. For

information regarding the various tests available, contact:

National Institute of Standards and Technology,

Measurements Services Office

325 Broadway, Boulder CO 80303-3328 USA,

Telephone: (303) 497-3753

Frequency Stability (Time Domain)

This is an engineering-level measurement requiring a special test

setup. The test setup must be carefully designed to eliminate all

sources of noise. For more information on how to make this

measurement, see Application Note 358-12. Also, see NIST Technical

Note 1337 (available from US Government Printing Office,

Washington DC., USA). This is an excellent theoretical as well as

technical reference for this measurement.

Phase Noise (Frequency Domain)

This measurement requires the HP 3048A Phase Noise Measurement

System or equivalent, a highly specialized test system. In order to

perform properly, this system must contain a reference oscillator with

phase noise characteristics that are equal to or better than the 58503B

or 59551A.

This completes the performance tests.

D-24

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Complete Performance Tests

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Appendix D Performance Tests

58503B Performance Test Record

Model 58503B GPS Time and Frequency Reference Receiver

Serial Number: __________________________ Repair/Work Order No. _______________________

Test Performed By:_______________________ Temperature: ________________________________

Date: ___________________________________ Relative Humidity: ___________________________

Notes: ________________________________________________________________________________

Line Number

Operational Verification

Test Results

Pass Fail

10 MHz Verification

____

1 PPS Verification

Time of Day RS-232 Serial Interface Verification

Antenna Power Verification

Front Panel Display/Keypad Verification

(Option 001 Only)

58503B Complete Performance Tests

Test Number Test Description

Results

Limits

Better than 1 x 10

−12

10 MHz Frequency Accuracy

1. ______________

for a

one day average, 0° to

50° C.

and

1 PPS Jitter (Locked to GPS)

2. _____________

<750 ps with at least one

satellite in view, Selective

Availability on.

−10

10 MHz Holdover Aging

and

1. ______________

2. _____________

<1 x 10 /day average

frequency change in

24 hours unlocked after

3 days locked operation

for any 10° C range

1 PPS Accumulated Time error

(Unlocked)

between 10° C and 40° C.

<8.6 us accumulated in

24 hours unlocked after

3 days of locked operation

with a fixed antenna

location, any 10° C range

between 10° C and 40° C.

1 PPS Time Accuracy (Locked)

_____________

10 MHz Frequency Stability

(Time Domain) and Phase Noise

(Frequency Domain)

Measurement

D-26

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Appendix D Performance Tests

59551A Performance Test Record

Model 59551A GPS Measurements Synchronization Module

Serial Number: __________________________ Repair/Work Order No. _______________________

Test Performed By:_______________________ Temperature: ________________________________

Date: ___________________________________ Relative Humidity: ___________________________

Notes: ________________________________________________________________________________

Line Number

Operational Verification

Test Results

Pass Fail

10 MHz Verification

____

1 PPS Verification

IRIG-B Verification

Time of Day RS-232 Serial Interface Verification

Antenna Power Verification

Time Tagging (Stamping) Verification

Programmable Pulse Verification

59551A Complete Performance Tests

Test Number Test Description

Results

Limits

Better than 1 x 10

−12

10 MHz Frequency Accuracy

1. ______________

for a

one day average, 0° to

50° C.

and

1 PPS Jitter (Locked to GPS)

2. _____________

<750 ps with at least one

satellite in view, Selective

Availability on.

−10

10 MHz Holdover Aging

and

1. ______________

2. _____________

<1 x 10 /day average

frequency change in

24 hours unlocked after

3 days locked operation

for any 10° C range

1 PPS Accumulated Time error

(Unlocked)

between 10° C and 40° C.

<8.6 us accumulated in

24 hours unlocked after

3 days of locked operation

with a fixed antenna

location, any 10° C range

between 10° C and 40° C.

1 PPS Time Accuracy (Locked)

_____________

10 MHz Frequency Stability

(Time Domain) and Phase Noise

(Frequency Domain)

Measurement

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59551A Performance Test Record

D-28

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Appendix E 58503B Specifications

Specifications and Characteristics

The specifications and characteristics of the 58503B GPS Time and

Frequency Reference Receiver are provided in this chapter.

GPS Receiver Features

Eight-channel, parallel tracking GPS engine

C/A Code, L1 Carrier

SmartClock™ technology

Enhanced GPS technology

E-2

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Appendix E 58503B Specifications

Specifications and Characteristics

Note 2

10 MHz Output

Specifications

Locked:

Additional Features

When a quartz crystal oscillator has not

been operated for a period of time, or if it

has been subjected to severe thermal or

mechanical shock, as might be

Alarm Output: TTL open collector

with internal pull-up resistor.

Circuit can sink up to 10 ma.

Provides a logic output to allow

monitoring of normal (H) and

abnormal (L) operation

Frequency Accuracy: Better than

1 × 10⁻¹², for a one-day average,

0° C to 50° C.

encountered during product shipment, the

oscillator may take some time to stabilize.

In most cases, the oscillator will drift and

then stabilize at or below its specified rate

within a few days after being turned on.

In isolated cases, depending upon the

amount of time the oscillator has been off

and the environmental conditions it has

experienced, the oscillator may take up to

one week to reach its specified aging rate

and to operate without significant

externally and remotely.

BNC connector.

Unlocked:

Holdover aging:

<1 × 10⁻¹⁰per day average

frequency change in 24 hours of

unlocked operation. (See Note 1.)

Front Panel Indicators (LEDs):

Power

GPS Lock

Holdover Mode

Alarm

Phase Noise: (Locked)

frequency “jumps.”

Offset From

Signal (Hz)

SSB Phase

Noise (dBc)

−85

Remote Interface:

When a GPS Receiver is initially turned

on and locked to the GPS satellite

system, it will achieve GPS lock within

30 minutes of operation. It has a 95%

probability of meeting unlocked (holdover)

specifications after 24 hours of warmup,

followed by GPS lock for 48 hours. The

longer GPS Receiver (and its quartz

oscillator) operates, the better its stability

and unlocked (holdover) performance

becomes.

RS-232-C DTE configuration:

Complete remote control and

interrogation of all instrument

functions and parameters.

−125

100

1000

10000

−135

−140

−145

Factory defaults: baud rate 9600,

8 data bits, 1 start bit, 1 stop bit,

no parity. Other settings are

programmable.

Time Domain Stability: (Locked)

(See graph on next page.)

Averaging

Root Allan

Time Seconds Variance

Connector: 25-pin female

rectangular D subminiature on

rear panel.

1.5 × 10⁻¹⁰

1.5 × 10⁻¹¹

5 × 10⁻¹²

5 × 10⁻¹¹

1 PPS Output

0.01

0.1

100

1000

Specifications

Time code output is available to a

computer immediately preceding

the 1 PPS signal for the current

second.

Locked:

Jitter of leading edge: <750 ps

rms with at least one satellite in

view, SA on.

Supplemental Information

Time Accuracy:

Environmental

Specifications

• Waveform: Sine wave

• Amplitude: >1 volt p-p into a

50Ω load

• Harmonic Distortion:

<−25 dBc (Typical)

• Non-harmonic signals:

<−60 dBc (Typical)

• Source impedance:

50Ω (nominal)

<110 ns with respect to UTC

(USNO MC)—95% probability

when unit is properly installed,

calibrated, and locked to GPS.

Time and Frequency Reference

Receiver (58503B)

Unlocked:

Operating: 0° C to +50° C

Storage: −40° C to +80° C

Accumulated time error: <8.6 µs

accumulated in 24 hours of

unlocked operation. (See Note 1.)

Antenna (58532A)

Operating: −30° C to +80° C

Storage: −40° C to +85° C

• Coupling: ac

• Connector: BNC

Supplemental Information

• Pulse Width: 26 µsec

• Amplitude: >2.4 volts into

50Ω load. (TTL compatible)

• Connector: BNC

Note 1

This specification has a 95% probability,

and is based on the availability of four or

more GPS satellites during three days of

locked operation with a fixed antenna

location. The temperature must remain

within a 10° C range between 10° C and

40° C.

• Rise time: <25 ns

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Appendix E 58503B Specifications

Specifications and Characteristics

Power Requirements

AC Power (standard):

90 to 132 Vac or 198 to 264 Vac,

automatically selected;

50 to 60 Hz.

Option AWQ:

Unit accepts:

+24 Vdc or + 48 Vdc nominal.

Actual operating range:

+19 to +60 Vdc operating range.

Greater than

+23 Vdc required to start.

Input Power (all options):

<35 watts (nominal).

Weight and Size

10 MHz Root Allan Variance

Dimensions:

88.5 mm H ×

212.6 mm W × 348.3 mm D.

Half-Rack Module

Weight: 3.6 kg (8 lbs).

E-4

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Appendix E 58503B Specifications

Specifications and Characteristics

Other Information

The standard 58503B does not include a display or a keypad. While not

necessary, it may be convenient to track the Receiver’s progress during

installation and startup by monitoring the satellites being tracked,

location (position), time and other parameters. The 58503B, however,

is supplied with a small Windows 3.1 program named SatStat (59551-

13401), which can serve to display important parameters. SatStat

operates on any PC that can run Windows 3.1, and that has an

available serial interface.

SatStat provides several useful functions. It continuously polls the

RS-232C interface and displays Receiver information most likely to be

of interest. This includes satellites being tracked along with their

elevation and azimuth, SmartClock State (locked, holdover, etc.),

antenna coordinates, time and frequency figures of merit and other

data. In addition, a clock window is provided to display time of day in

real time. Finally, SatStat allows you to easily change many receiver

parameters, such as antenna delay, by simply picking the item from a

pop-up menu and entering a new value. With SatStat and a PC,

you can monitor and control many aspects of the Receiver status

without developing software.

Achieving accurate time of day requires care in determining cable

delays, Receiver bias, position (Lat, Lon, Alt), atmospheric conditions

and other parameters which are dependent on each individual

installation.

Options and Accessories

Available options and accessories include an antenna, an antenna

environmental cover and ground plane, pre-configured cables,

a lightning arrester, an antenna line amplifier, a built-in display and

dc power.

Operating and Programming Guide

E-5

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Appendix E 58503B Specifications

Specifications and Characteristics

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E-6

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59551A Specifications

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Appendix F 59551A Specifications

Specifications and Characteristics

The specifications and characteristics of the 59551A GPS

Measurements Synchronization Module are provided in this chapter.

GPS Receiver Features

Eight-channel, parallel tracking GPS engine

C/A Code, L1 Carrier

SmartClock™ technology

Enhanced GPS technology

Operating and Programming Guide

F-2

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Appendix F 59551A Specifications

Specifications and Characteristics

amount of time the oscillator has been off

and the environmental conditions it has

experienced, the oscillator may take up to

one week to reach its specified aging rate

and to operate without significant

Remote Interface:

(Two RS-232C Ports)

1 PPS Output

Specifications

Locked:

RS-232-C DTE configuration:

PRIMARY PORT

Complete remote control and

interrogation of all instrument

functions and parameters.

SECONDARY PORT

Interrogation of all instrument

functions and parameters.

Factory defaults: baud rate 9600—

8 data bits, 1 start bit, 1 stop bit,

no parity. Other settings are

programmable.

Connectors: 9-pin female

rectangular D subminiature

(DB-9) on front panel, 25-pin

female rectangular D

Jitter of leading edge: <750 ps

rms with at least one satellite in

view.

frequency “jumps.”

When a GPS Receiver is initially turned

on and locked to the GPS satellite

system, it will achieve GPS lock within

30 minutes of operation. It has a 95%

probability of meeting unlocked (holdover)

specifications after 24 hours of warmup,

followed by GPS lock for 48 hours. The

longer GPS Receiver (and its quartz

oscillator) operates, the better its stability

and unlocked (holdover) performance

becomes.

Time Accuracy:

<110 ns with respect to UTC

(USNO MC)—95% probability

when unit is properly installed,

calibrated, and locked to GPS.

Unlocked:

Accumulated time error: <8.6 µs

accumulated in 24 hours of

unlocked operation. (See Note 1.)

Three Time-tag Inputs

Supplemental Information

Received signal: TTL, 50Ω.

Time-tag accuracy: same as the

accuracy of the 59551A.

Quantization: 100 ns

Input Interface: BNC

Minimum Pos/Neg pulse width:

200 ns

subminiature (DB-25) on rear

panel.

Time code output is available to a

computer immediately preceding

the 1 PPS signal for the current

second.

• Pulse Width: 26 µsec

• Amplitude: >2.4 volts into

50Ω load. (TTL compatible)

• Connector: BNC

• Rise time: <5 ns

Three time-tag buffers: 256 events

each, retrievable via RS-232C.

Minimum time between events:

1 ms

Maximum stamp rate:

1 measurement per ms

Additional Features

Alarm BITE Output:

Basic unit output: solid state relay

(normally open); closed contact

indicates system fault or loss of

satellite lock. Contact rating

200 Vdc @ 0.5 amps.

Timer/Clock Output

Programmable Pulse Output:

Single pulse at the time

Connector: Twin BNC

IRIG-B123 Output Port

BNC connector

programmed via RS-232C port,

or repetitive output pulse at a

programmable repetition period

from 1 second to 1 year.

Note 1

Quantization: 100 ns

This specification has a 95% probability,

and is based on availability of four or more

GPS satellites during three days locked

operation with a fixed antenna location.

The temperature must remain within a

10° C range between 10° C and 40° C.

Accuracy: same as the time

accuracy of the 59551A.

Front Panel Indicators (LEDs):

Power

GPS Lock

Holdover Mode

Alarm

Note 2

When a quartz crystal oscillator has not

been operated for a period of time, or if it

has been subjected to severe thermal or

mechanical shock, as might be

encountered during product shipment, the

oscillator may take some time to stabilize.

In most cases, the oscillator will drift and

then stabilize at or below its specified rate

within a few days after being turned on.

In isolated cases, depending upon the

Operating and Programming Guide

F-3

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Appendix F 59551A Specifications

Specifications and Characteristics

Environmental Specifications

Measurements Synchronization Module (59551A)

Operating: 0° C to +50° C

Storage: −40° C to +80° C

Antenna (58532A)

Operating: −40° C to +80° C

Storage: −40° C to +85° C

Power Requirements

AC Power:

90 to 132 Vac or 198 to 264 Vac, automatically selected;

50 to 60 Hz.

DC Power:

129 Vdc nominal (115 to 140 Vdc operating range).

Input Power (all options):

<35 watts (nominal).

Weight and Size

Dimensions:

88.5 mm H × 212.6 mm W × 348.3 mm D. Half-Rack Module

Weight: 3.6 kg (8 lbs).

Surge Withstand:

Meets IEEE/ANSI C37.90, C37.90.1

Operating and Programming Guide

F-4

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Appendix F 59551A Specifications

Specifications and Characteristics

Other Information

The standard 59551A does not include a display or a keypad. While not

necessary, it may be convenient to track the Receiver’s progress during

installation and startup by monitoring the satellites being tracked,

location (position), time and other parameters. The 59551A, however,