Agilent 58503A Operating and Programming Guide

Download

58503B

GPS Time and Frequency

Reference Receiver

097-58503-13

Issue 2: Jul 00

and

59551A

GPS Measurements

Synchronization Module

Operating and Programming

Guide

This guide describes how to operate the Symmetricom 58503B GPS Time and Frequency Reference Receiver and 59551A GPS Measurements Synchronization Module via the RS-232C port(s). The information in this guide applies to instruments having the number prefix listed below, unless accompanied by a “Manual Updating Changes” package indicating otherwise.

SERIAL PREFIX NUMBER:3805A and above (58503B), 3805A and above (59551A)

Warning Symbols That May Be Used In This Book

Instruction manual symbol; the product will be marked with this symbol when it is necessary for the user to refer to the instruction manual.

Instruments with serial numbers below 3805A may have earlier versions of firmware installed. There are no operator-specific differences in previous versions of firmware.

FIRMWARE REVISION:3805A and above (58503B), 3805A and above (59551A)

Firmware revision can be identified by using a “*IDN?” command sent to the Receiver via RS-232C port. See the section “Connecting a Computer or Modem,” in Chapter 2, “Serial Interface Capabilities,” of this guide for instructions on connecting a computer or modem to these products.

For assistance, contact:

Symmetricom, Inc. 2300 Orchard Parkway San Jose, CA 95131-1017

U.S.A. Call Center:

888-367-7966 (from inside U.S.A. only – toll

free)

408-428-7907

Indicates hazardous voltages.

Indicates earth (ground) terminal.

Indicates terminal is connected to chassis when such connection is not apparent.

Indicates Alternating current.

Indicates Direct current.

U.K. Call Center:

+44.7000.111666 (Technical Assistance) +44.7000.111888 (Sales)

Fax: 408-428-7998

E-mail: ctac@symmetricom.com

Internet: http://www.symmetricom.com

Contents

In This Guide

1 Front and Rear Panels at a Glance

58503B Front Panel at a Glance 2 58503B/Option 001 Front-Panel Display/Keypad at a

Glance 3 58503B Rear Panel at a Glance 4 59551A Front Panel at a Glance 5 59551A Rear Panel at a Glance 6

2 Serial Interface Capabilities

Chapter Contents 2 About the RS-232C Serial Port(s) 3

PORT 1 Rear-Panel RS-232C Serial Port 3 PORT 2 Front-Panel RS-232C Serial Port (59551A Only) 4

Connecting a Computer or Modem 5

To Connect the GPS Receiver to a PC or Modem Via the Rear-Panel PORT 1 6

Connecting to the Personal Computer (PC) 6 Connecting to a Modem 6

Making Your Own Cables 8 Configuring the RS-232C Port(s) 9

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

3Visual User Interface

Chapter Contents 2 Using and Reading the Visual User Interface (the Receiver

Status Screen) 3

Tutorial on Using the Status Screen to Interface With the Receiver 3

Demonstration of Holdover Operation 8

Receiver Status Screen Data 11

SYNCHRONIZATION Section of the Status Screen 12

SYNCHRONIZATION Summary Line 12 SmartClock Mode 12

Operating and Programming Guide iii

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

4 Command Quick Reference

Chapter Contents 2 An Introduction to GPS Receiver Commands 4

SCPI Conformance Information 4 Command Syntax Conventions 4 Command Presentation 4

GPS Satellite Acquisition 5 1 PPS Reference Synchronization 7 Operating Status 8 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

5 Command Reference

Chapter Contents 2 Command Syntax Conventions 4 Description Format 5

Commands and Returns 5 Query-Specific Information 6 Description of Response Formats (ASCII-encoded) 6

iv Operating and Programming Guide

Contents

GPS Satellite Acquisition 7 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

A Error Messages

Introduction 2 Reading an Error 2 Error Queue 3 Error Types 4

No Error 4 Syntactic Error 4 Semantic Error 5 Hardware/Firmware Error 5 Query Error 5

General Error Behavior 6 List of Errors 7

B Command Syntax and Style

Appendix Contents 2 Command Types, Format, and Elements 3

Command Types 3 Command Formats 3

Common Command Format 3 SCPI Command and Query Format 3

Elements of SCPI Commands 4

Common Command Syntax 4 Subsystem Command Syntax 4 Abbreviated Commands 5 Keyword Separator 5 Parameter Data Types 5 Parameter Separator 6 Query Parameters 6 Suffixes 6 Suffix Elements 6 Suffix Multipliers 7 Command Terminator 7

Operating and Programming Guide v

Contents

Using Multiple Commands 7

Program Messages 7 Program Message Syntax 7

Elements of Response Messages 9

Response Messages 9 Response Message Syntax 9 Response Formats 10

Reference Documentation 12

C Receiver Firmware Installation

Downloading New Firmware Using SatStat Program 2

D Performance Tests

Introduction 2

Operational Verification 2 Complete Performance Tests 2 Test Record 2

Equipment Required 3 Before You Start 4 Operational Verification 5

Introduction 5 Power-Up Procedure 5 10 MHz Verification (58503B Only) 6 1 PPS Verification 6 IRIG-B Verification (59551A Only) 7 Time of Day and PORT 1 RS-232C Serial Interface

Verification 8 Antenna Power Verification 9 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

vi Operating and Programming Guide

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 27

E 58503B Specifications

Specifications and Characteristics 2

GPS Receiver Features 2 Other Information 5 Options and Accessories 5

F 59551A Specifications

Specifications and Characteristics 2

GPS Receiver Features 2 Other Information 5 Options and Accessories 5

Command Index

General Index

Operating and Programming Guide vii

Contents

viii Operating and Programming Guide

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.

Operating and Programming Guide ix

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

x Operating and Programming Guide

Front and Rear Panels at a Glance

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.

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).

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.

4 When the Alarm indicator

illuminates, it indicates that the Receiver has detected an internal condition that requires attention.

1-2 Operating and Programming Guide

Chapter 1 Front and Rear Panels at a Glance

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

1 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.

2 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.

3 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.

Operating and Programming Guide 1-3

Chapter 1 Front and Rear Panels at a Glance

58503B Rear Panel at a Glance

1 ANT N-type (female) connector for

GPS Antenna connection.

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.

3 10 MHz OUT output for user-specific

applications.

4 1PPS connector for outputting a

continuous 1 Pulse Per Second signal.

Option 002 1PP2S

(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.).

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.

7 POWER input jack.

1-4 Operating and Programming Guide

Chapter 1 Front and Rear Panels at a Glance

59551A Front Panel at a Glance

When the Power indicator

illuminates, it indicates that the proper input power is supplied to the Module.

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).

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.)

4 When the Alarm indicator

illuminates, it indicates that the Module has detected an internal condition that requires attention.

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

serial interface port for local monitoring and retrieving data stored in the Module’s memory data.

Operating and Programming Guide 1-5

Chapter 1 Front and Rear Panels at a Glance

59551A Rear Panel at a Glance

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

connector for outputting a continuous one pulse per second signal.

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.)

4 Time tag input connectors for

receiving TTL conditioned time tagging signals.

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]).

6 ANTENNA N-type (female)

connector for GPS antenna connection.

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 Operating and Programming Guide

Serial Interface Capabilities

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

– PORT 1 Rear-Panel RS-232C Serial Port page 2-3

– 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

the Rear-Panel PORT 1

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

the Rear-Panel PORT 1

• Configuring the RS-232C Port(s) page 2-9

– Making Changes to the Serial Port Settings

(If Needed)

– Determining the Serial Port Settings page 2-11

page 2-4

page 2-6

page 2-10

2-2 Operating and Programming Guide

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 Number

2 Output Transmit Data (TxD). GPS Receiver output.

3 Input Receive Data (RxD). GPS Receiver input.

Input/Output Description

_____

Signal Ground (SG)

Operating and Programming Guide 2-3

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 Number

2 Input Receive Data (RxD). GPS Receiver input.

3 Output Transmit Data (TxD). GPS Receiver output.

Input/Output Description

_____

Signal Ground (SG)

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 Operating and Programming Guide

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.

Operating and Programming Guide 2-5

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)

NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO SERVICE TRAINED PERSONNEL.

WARNING:

1 pps Programmable

WARNING:

INPUTS

OUTPUTS

Time Tag1Time Tag2Time Tag

Irig-B

TOD

! !

Port 1

FOR CONTINUED FIRE PROTECTION, USE SPECIFIED ~ LINE FUSE.

SERIAL PLATE

FOR LABORATORY USE BY QUALIFIED PERSONNEL FOUR USAGE EN LABORATOIRE PAR PERSONNEL QUALIFIE

ANTENNA

ALARM BITE

POWER

129 VDC

48 VDC

129 VDC

Computer

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 Operating and Programming Guide

Chapter 2 Serial Interface Capabilities

Connecting a Computer or Modem

GPS Receiver (Rear view)

NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO SERVICE TRAINED PERSONNEL.

WARNING:

OUTPUTS

1 pps Programmable

Irig-B

TOD

! !

Port 1

FOR CONTINUED FIRE PROTECTION, USE SPECIFIED ~ LINE FUSE.

WARNING:

INPUTS

Time Tag1Time Tag2Time Tag

FOR LABORATORY USE BY QUALIFIED PERSONNEL FOUR USAGE EN LABORATOIRE PAR PERSONNEL QUALIFIE

SERIAL PLATE

ANTENNA

ALARM BITE

POWER

129 VDC

48 VDC

129 VDC

HP 40242M or equivalent

Modem set to

Auto-Answer

Telephone

Line

Figure 2-2 Connecting the GPS Receiver to a Modem

Operating and Programming Guide 2-7

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, DTEto-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.

RS-232C (9-pin)

PC input

PC output

Data

Terminal

Equipment

GND

DE-9P

Male

DE-9S-to-DE-9P

(DTE-to-DCE) Interface Cable

11 22 33 44 55 66 77 88 99

DE-9S Female

DE-9P

Male

Data Communications Equipment

59551A PORT 2

RS-232C (9-pin)

Instrument input

Instrument output

GND

DE-9S 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.

RS-232C (9-pin)

PC input

PC output

Data

Terminal

Equipment

RX TX

GND

DE-9P Male

1 2 3 4 5 6 7 8 9

DE-9S Female

DE-9S-to-DB-25P

(DTE-to-DTE)

Interface cable

DB-25P

Male

Data Terminal Equipment

PORT 1

RS-232C (25-pin)

1 2 3 4 5 6 7

8 20 22

DB-25S Female

TX RX

GND

Instrument output Instrument input

Figure 2-4 DE-9S-to-DB-25P (DTE-to-DTE) Serial Interface Connection to PORT 1

2-8 Operating and Programming Guide

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

Software Pacing NONE XON or NONE

Baud Rate 9600 1200, 2400, 9600, or 19200

Parity NONE EVEN, ODD, or NONE

Data Bits 8 7 or 8

Stop Bits 1 1 or 2

Full Duplex ON 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 9600 1200, 2400, 9600, or 19200

Parity NONE EVEN, ODD, or NONE

Data Bits 8 Fixed at 7 when parity is even or odd.

Fixed at 8 when parity is none.

Stop Bits 1 Fixed (no choices available)

Full Duplex ON ON or OFF

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

Operating and Programming Guide 2-9

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 Operating and Programming Guide

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?

Operating and Programming Guide 2-11

Chapter 2 Serial Interface Capabilities

Configuring the RS-232C Port(s)

This page intentionally left blank.

2-12 Operating and Programming Guide

Visual User Interface

Using the Receiver Status Screen

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)

– Tutorial on Using the Status Screen to Interface With

the Receiver page 3-3

– Demonstration of Holdover Operation page 3-8

• Receiver Status Screen Data page 3-11

– SYNCHRONIZATION Section of the Status Screen page 3-12

– ACQUISITION Section of the Status Screen page 3-14

– HEALTH MONITOR Section of the Screen page 3-18

• The Receiver Status Screen at a Glance (foldout) page 3-20

page 3-3

3-2 Operating and Programming Guide

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

:SYSTEM:STATUS?

query. (Refer to Chapter 1,

• 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

:SYSTEM:STATUS?

Type

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.

at the scpi> prompt.

Operating and Programming Guide 3-3

Chapter 3 Visual User Interface

Using and Reading the Visual User Interface (the Receiver Status

Screen)

---------------------------- ---------------------------SYNCHRONIZATION SmartClock Mode

Locked Recovery Holdover

Power-up:GPS acquisition

ACQUISITION Tracking: 0

ELEV MASK HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

10 deg

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

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

Not Tracking: 6 PRN

El Az *1 -- --*6 -- --*9 -- ---

*14 -- --*22 -- --*24 -- ---

*attempting to track

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

Receiver Status

Outputs Invalid Reference Outputs TFOM 1PPS TI HOLD THR Holdover Uncertainty Predict --

Time UTC GPS 1PPS Invalid: not tracking ANT DLY

Position MODE

INIT LAT INIT LON INIT HGT

[

1.000 us

[GPS 1PPS Invalid]

12:00:00[?] 01 Jan 1996

0 ns

Survey: 0% complete Suspended:track <4 sats

NW0:00:00.000

0:00:00.000

FFOM

0 m (GPS)

[ 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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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.

---------------------------- ---------------------------SYNCHRONIZATION SmartClock Mode

Locked to GPS: stabilizing frequency

Recovery Holdover Power-up

ACQUISITION Tracking: 5

PRN El Az

El 70 46 33 28 65

Az 337 188

113

7 15 19 22

ELEV MASK HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

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

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

10 deg

Not Tracking: 4 PRN

C/N

49 48 38 36 49

9 11 292

16 24 243

*26 Acq..

31 -- ---

*attempting to track

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

Receiver Status

[

Outputs Valid/Reduced Accuracy Reference Outputs TFOM FFOM

1PPS TI HOLD THR Holdover Uncertainty Predict --

Time UTC GPS 1PPS Synchronized to UTC ANT DLY

Position MODE

AVG LAT AVG LON AVG HGT

+71 ns relative to GPS

1.000 us

[GPS 1PPS Valid]

17:56:44 31 Jan 1996

0 ns

Survey: 1.2% complete

NW37:19:34.746

121:59:50.502

+34.14 m (GPS)

[ OK ]

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.

Operating and Programming Guide 3-5

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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Using and Reading the Visual User Interface (the Receiver Status

Screen)

---------------------------- ---------------------------SYNCHRONIZATION

SmartClock Mode

Locked to GPS: stabilizing frequency

Recovery Holdover Power-up

ACQUISITION Tracking: 6

PRN El Az

El 70 35 40 71 19

Az 301 186 102

317

7 19 22 26 31 3516 41

ELEV MASK HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

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

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

Not Tracking: 1

C/N

PRN

16 13 258 38 38 39 36

10 deg

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

Receiver Status

Outputs Valid/Reduced Accuracy

[

Reference Outputs TFOM FFOM 1PPS TI HOLD THR Holdrover Uncertainty Predict 432.0 us/initial 24 hrs

Time UTC GPS 1PPS Synchronized to UTC ANT DLY

Position MODE

AVG LAT AVG LON AVG HGT

+20 ns relative to GPS

1.000 us

[GPS 1PPS Valid]

18:47:07 31 Jan 1996

0 ns

Survey: 5.4% complete

NW37:19:34.937

121:59:50.457

+67.94 m (GPS)

[ 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.

Operating and Programming Guide 3-7

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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Using and Reading the Visual User Interface (the Receiver Status

Screen)

---------------------------- ---------------------------SYNCHRONIZATION SmartClock Mode

Locked to GPS Recovery Holdover: GPS 1PPS invalid

Power-up

ACQUISITION Tracking: 0

ELEV MASK HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

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

Holdover Duration: 0m 14s Present 1.0 us

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

Not Tracking: 7 PRN

El Az *2 71 316 *7 41 186

15 11 86 *19 35 107 *22 68 78 *26 23 314

10 deg

*attempting to track

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

Receiver Status

PRN El Az

*31 12 29

[

Outputs Valid/Reduced Accuracy Reference Outputs TFOM FFOM

1PPS TI -HOLD THR Holdover Uncertainty Predict 432.0 us/initial 24 hrs

Time UTC GPS 1PPS Inaccurate: not tracking ANT DLY

Position MODE

LAT LON HGT

1.000 us

[GPS 1PPS Invalid]

20:56:14 31 Jan 1996

0 ns

Survey: 71.1% complete

NW37:19:32.472

121:59:51.784

+42.19 m (GPS)

[ 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.

Operating and Programming Guide 3-9

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.

---------------------------- ---------------------------SYNCHRONIZATION SmartClock Mode

Locked to GPS: Stabilizing frequency

Recovery Holdover Power-up

ACQUISITION Tracking: 6

PRN

7 19 22 26 31 12 27

ELEV MASK HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

71 34 41 67 24

Az 317 185 101

312

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

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

Not Tracking: 0

C/NEl

40 38 37 40 37 36

10 deg

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

Receiver Status

[

Outputs Valid/Reduced Accuracy Reference Outputs TFOM FFOM

1PPS TI +10.6 ns relative to GPS HOLD THR Holdover Uncertainty Predict 432.0 us/initial 24 hrs

Time UTC GPS 1PPS Synchronized to UTC ANT DLY

Position MODE

LAT LON HGT

1.000 us

[GPS 1PPS Valid]

20:59:28 31 Jan 1996

0 ns

Survey: 71.4% complete

NW37:19:32.486

121:59:52.082

+40.06 m (GPS)

[ 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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Receiver Status Screen Data

This section defines the data displayed in the Receiver Status Screen, shown in Figure 3-6.

---------------------------- ---------------------------SYNCHRONIZATION SmartClock Mode

Locked to GPS Recovery Holdover Power-up

ACQUISITION Tracking: 6

El Az

PRN

2 49 243 16 24 282 18 38 154 19 65 52 27 62 327 31 34 61

ELEV MASK HEALTH MONITOR

Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

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

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

Not Tracking: 1

C/N

PRN El Az

14 11 82 46 47 49 49 47

10 deg

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

Receiver Status

[ Reference Outputs TFOM FFOM

1PPS TI +7.2 ns relative to GPS HOLD THR Holdover Uncertainty Predict 49.0 us/initial 24 hrs

Time UTC GPS 1PPS Synchronized to UTC ANT DLY

Position MODE

AVG LAT AVG LON AVG HGT

1.000 us

+1 leap second pending

23:59:59 31 Dec 1995

120 ns

Survey: 17.5% complete

NW37:19:32.264

121:59:52.112

Outputs Valid

[GPS 1PPS Valid]

+41.86 m (GPS)

[ 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.

Operating and Programming Guide 3-11

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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 while the Receiver (unit) is warming up, Outputs Valid/

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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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

*0 less than 1 5 104 – 10

*1 1 – 10 6 105 – 10

*2 10 – 100 7 106 – 10

3 100 – 1000 8 107 – 10

4 103 – 10

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.

(in nanoseconds)

TFOM Value

9 greater than 10

Time Error (in nanoseconds)

Operating and Programming Guide 3-13

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

0 PLL stabilized — internal 10 MHz signal within

specification.

1 PLL stabilizing

2 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.

3 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.

El indicates the predicted elevation angle, from a range of 0

. The predicted elevation is derived from the

to 90 almanac.

- - indicates that the elevation angle is unknown (the

almanac did not provide this data).

Az 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.

(59551A)

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.

The health and status indicators in the Not Tracking table are described as follows:

Ignore indicates that the user has chosen to exclude this

satellite from a list of satellites available for tracking.

Not OK indicates GPS has reported that this satellite is

unhealthy.

Acq 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.

Operating and Programming Guide 3-15

Chapter 3 Visual User Interface

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 to GPS Time

Synchronized To U T C

Assessing stability ...

Inaccurate, not tracking

Inaccurate, inacc position

Absent or freq incorrect

1 PPS locked to GPS, referenced to GPS Time.

1 PPS locked to GPS, referenced to UTC.

applying hysteresis to locked 1 PPS signal.

not tracking satellites.

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

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

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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 LO N indicates the average longitude (East or West) position of the unit in degrees, minutes, and seconds.

AVG HG T 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).

Operating and Programming Guide 3-17

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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 Internal power supply voltage(s) exceeds tolerance.

Oven Pwr Oscillator oven power supply voltage exceeds tolerance.

OCXO 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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This Page Intentionally Left Blank.

Operating and Programming Guide 3-19

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The Receiver Status Screen at a Glance

3-20 Operating and Programming Guide

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The Receiver Status Screen at a Glance

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

Operating and Programming Guide 3-21

Chapter 3 Visual User Interface

The Receiver Status Screen at a Glance

3-22 Operating and Programming Guide

Command Quick Reference

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

– SCPI Conformance Information page 4-4

– Command Syntax Conventions page 4-4

– Command Presentation page 4-4

• GPS Satellite Acquisition page 4-5

– Facilitating Initial Tracking page 4-5

– Establishing Position page 4-5

– Selecting Satellites page 4-6

– Compensating for Antenna Delay page 4-6

– Monitoring Acquisition page 4-6

• 1 PPS Reference Synchronization page 4-7

– Monitoring 1 PPS Synchronization page 4-7

– Assessing 1 PPS Quality page 4-7

– Operating in Holdover page 4-7

• Operating Status page 4-8

– Receiver Operation at a Glance page 4-8

– Reading the Error Queue page 4-8

– Reading the Diagnostic Log page 4-8

– Monitoring Status/Alarm Conditions page 4-8

– Assessing Receiver Health page 4-9

4-2 Operating and Programming Guide

Chapter 4 Command Quick Reference

Chapter Contents

• System Time page 4-10

– Identifying Time of Next 1 PPS Reference Edge page 4-10

– Reading Current Time page 4-10

– Applying Local Time Zone Offset page 4-10

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

– Reading Leap Second Status page 4-10

• Programmable Pulse Output (59551A Only) page 4-11

• Event Time Stamping (59551A Only) page 4-12

– Defining the Time-stamped Edge page 4-12

– Clearing Time Stamp Memory page 4-12

– Reading Time Stamps page 4-12

– Processing Memory Overflow page 4-12

• Serial Interface Communication page 4-13

– Configuring I/O Port 1 page 4-13

– Configuring I/O Port 2 (59551A Only) page 4-13

– Recovering the Last Query Response page 4-13

• Receiver Initialization page 4-14

• Receiver Identification/Upgrade page 4-15

– Reading Product Identification page 4-15

– Installing Firmware via I/O Port 1 page 4-15

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

Reporting System at a Glance (foldout)

page 4-17

Operating and Programming Guide 4-3

Chapter 4 Command Quick Reference

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>,

E or W, <longitude degree>,

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

<latitude minute>, <latitude second>,

Establishing Position

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

<latitude minute>,

E or W, <longitude degree>,

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?

<latitude second>,

Basic comman

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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? (59551A)

Returns list of satellites to ignore.

:GPS:SATellite:TRACking:INCLude <PRN>, ... , <PRN> (59551A) :GPS:SATellite:TRACking:INCLude? (59551A) :GPS:SATellite:TRACking:<select>:ALL (59551A) :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 comman

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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 comman

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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 comman

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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 comman

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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

:PTIMe:TCODe?

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

Reading Current Time

:PTIMe:DATE? or :SYSTem:DATE? :PTIMe:TIME? or :SYSTem:TIME? :PTIMe:TIME:STRing?

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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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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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

:SYSTem:COMMunicate:SERial1:BAUD?

R,F

:SYSTem:COMMunicate:SERial1:BITS 7 or 8 (59551A)

:SYSTem:COMMunicate:SERial1:BITS?

R,F

:SYSTem:COMMunicate:SERial1:FDUPlex ON or OFF

:SYSTem:COMMunicate:SERial1:FDUPlex?

R,F

:SYSTem:COMMunicate:SERial1:PACE XON or NONE

:SYSTem:COMMunicate:SERial1:PACE?

R,F

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

:SYSTem:COMMunicate:SERial1:PARity?

R,F

:SYSTem:COMMunicate:SERial1:SBITs 1 or 2 (59551A)

:SYSTem:COMMunicate:SERial1:SBITs?

R,F

Configuring I/O Port 2 (59551A Only)

:SYSTem:COMMunicate?

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

:SYSTem:COMMunicate:SERial2:BAUD?

R,F

:SYSTem:COMMunicate:SERial2:BITS?

R,F

:SYSTem:COMMunicate:SERial2:FDUPlex ON or OFF

:SYSTem:COMMunicate:SERial2:FDUPlex?

R,F

:SYSTem:COMMunicate:SERial2:PACE XON or NONE

:SYSTem:COMMunicate:SERial2:PACE?

R,F

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

:SYSTem:COMMunicate:SERial2:PARity?

R,F

:SYSTem:COMMunicate:SERial2:SBITs?

R,F

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.

: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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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

*CLS

:DIAGnostic:DOWNload <Motorola S-record>

:DIAGnostic:ERASe

:DIAGnostic:ERASe?

:SYSTem:ERRor?

:SYSTem:LANGuage "INSTALL" or "PRIMARY"

: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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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

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 page 5-4

• Description Format page 5-5

– Commands and Returns page 5-5

– Query-Specific Information page 5-6

• GPS Satellite Acquisition page 5-7

– Facilitating Initial Tracking page 5-9

– Establishing Position page 5-12

– Selecting Satellites page 5-17

– Compensating for Antenna Delay page 5-22

– Monitoring Acquisition page 5-24

• 1 PPS Reference Synchronization page 5-27

– Monitoring 1 PPS Synchronization page 5-28

– Assessing 1 PPS Quality page 5-30

– Operating in Holdover page 5-36

• Operating Status page 5-39

– Receiver Operation at a Glance page 5-41

– Reading the Error Queue page 5-42

– Reading the Diagnostic Log page 5-43

– Monitoring Status/Alarm Conditions page 5-48

– Assessing Receiver Health page 5-70

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Chapter Contents

• System Time page 5-73

– Identifying Time of Next 1 PPS Reference Edge page 5-74

– Reading Current Time page 5-75

– Applying Local Time Zone Offset page 5-77

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

– Reading Leap Second Status page 5-79

• Programmable Pulse Output (59551A Only) page 5-83

• Event Time Stamping (59551A Only) page 5-89

– Defining the Time-stamped Edge page 5-90

– Clearing Time Stamp Memory page 5-91

– Reading Time Stamps page 5-92

– Processing Memory Overflows page 5-97

• Serial Interface Communication page 5-100

– Configuring I/O Ports page 5-101

– Recovering the Last Query Response page 5-108

• Receiver Initialization page 5-109

• Receiver Identification/Upgrade page 5-113

– Reading Product Identification page 5-114

– Installing Firmware via I/O Port 1 page 5-115

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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Description Format

Commands and Returns

Command Index

Required characters are shown in bold type. "..." denotes one or more parameters; refer to Expanded Syntax for details.

Identifies a "basic" (fundamental) command.

Synopsis

Description

HP 59551A

:PULSe:STARt:DATE . . .

Identifies the date when the individual p the pulse sequence) is generated at th output.

This command identifies the date when the pulse sequence) is generated at the Pr

Product Compatibility

(if not present, the command is supported by both products)

Default Setting

(commands only)

Scope

(commands only)

:SYSTem:PRESet

NON-VOLATILE

1994,1,1

Command Mnemonic

Consult Appendix B: Command

and Style for notational style.

Syntax

Allowed Values, Range and Resolution

When the command may be issued

Secondary effects on other functions.

Concepts

Expanded Syntax

:PULSe:STARt:DATE <four-digit year

Parameter

The <four-digit year> range is 1994 to The <month> range is 1 to 12. The <day> range is 1 to 31.

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

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 o 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:COMMunicate:SERial:BAUD . . .

Sets the baud rate of PORT 1.

:SYSTem:PRESet

Not affected

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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 0 Single character,

one or zero

dd +10 Integer

d.d +1.5 Fixed-point number

d.dEe +1.00000E-009 Floating-point number

XYZ LOCK Alphanumeric characters

“ XYZ ” “19:49:51” or “No error” Quoted string

dd, ... +14, +15, +18, +22, +29 Comma-separated list of

integers

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

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

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Comma-separated list of quoted strings

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 ... (59551A) :GPS:SATellite:TRACking:IGNore? (59551A) :GPS:SATellite:TRACking:INCLude ... (59551A) :GPS:SATellite:TRACking:INCLude? (59551A) :GPS:SATellite:TRACking:<select>:ALL (59551A) :GPS:SATellite:TRACking:<select>:COUNt? :GPS:SATellite:TRACking:<select>:STATe? ...

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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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GPS Satellite Acquisition

Facilitating Initial Tracking ______________________________

:GPS:INITial:DATE . . .

Sets an approximate date for faster initial GPS acquisition.

:SYSTem:PRESet

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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GPS Satellite Acquisition

Facilitating Initial Tracking ____________________

:GPS:INITial:POSition . . .

Sets an approximate position for faster initial GPS acquisition.

(continued)

:SYSTem:PRESet

: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>,

E or W, <longitude degree>,

Parameter

<latitude minute>, <latitude second>,

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

<latitude degrees> 0 to 90 1 <longitude degrees> 0 to 180 1

<latitude minutes> 0 to 59 1 <longitude minutes> 0 to 59 1

<latitude seconds> 0 to 59.999 0.001 <longitude seconds> 0 to 59.999 0.001

<height, m> -1000.00 to

18,000.00

Context Dependencies

0.01

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 ____________________

:GPS:INITial:TIME . . .

Sets an approximate time for faster initial GPS acquisition.

(continued)

:SYSTem:PRESet

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.

Operating and Programming Guide 5-11

Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position_____________________________________

:GPS:POSition . . .

Defines the position of the Receiver.

:SYSTem:PRESet

latitude: N 0:00:00.000 longitude: E 0:00:00.000 height: 0 meters

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>,

E or W, <longitude degree>,

:GPS:POSition LAST :GPS:POSition SURVey

Parameter

<latitude minute>, <latitude second>,

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 following table lists the allowed settings of other parameters:

Parameter Range Precision Parameter Range Precision

<latitude degrees> 0 to 90 1 <longitude degrees> 0 to 180 1

<latitude minutes> 0 to 59 1 <longitude minutes> 0 to 59 1

<latitude seconds> 0 to 59.999 0.001 <longitude seconds> 0 to 59.999 0.001

<height, m> -1000.00 to

18,000.00

0.01

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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.

:GPS:POSition?

Returns the current average position of the GPS antenna.

RESPONSE FORMAT

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.

Operating and Programming Guide 5-13

Chapter 5 Command Reference

GPS Satellite Acquisition

Establishing Position___________________________

:GPS:POSition:ACTual?

Returns the current instantaneous position of the GPS antenna.

(continued)

RESPONSE FORMAT

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:

Context Dependencies

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

:GPS:POSition:HOLD:LAST?

Returns the last position-hold setting.

RESPONSE FORMAT

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:

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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Establishing Position ___________________________

:GPS:POSition:HOLD:STATe?

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

(continued)

RESPONSE FORMAT

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.

:GPS:POSition:SURVey:PROGress?

Returns percent completed while in survey mode.

RESPONSE FORMAT

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.

:GPS:POSition:SURVey:STATe . . .

Initiates survey mode during which the Receiver determines its position from satellite data.

:SYSTem:PRESet

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

Operating and Programming Guide 5-15

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GPS Satellite Acquisition

Establishing Position___________________________

:GPS:POSition:SURVey:STATe?

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

(continued)

RESPONSE FORMAT

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.

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

Selects position mode to be used at powerup.

:SYSTem:PRESet

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.

:GPS:POSition:SURVey:STATe:POWerup?

Returns the position mode to be used at powerup.

RESPONSE FORMAT

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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GPS Satellite Acquisition

Selecting Satellites _______________________________________

:GPS:SATellite:TRACking:EMANgle . . .

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

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.

:SYSTem:PRESet

NON-VOLATILE

:GPS:SATellite:TRACking:EMANgle?

Returns the GPS elevation mask angle value.

RESPONSE FORMAT

This query returns the GPS elevation mask angle value.

Response

The range is 0 degrees to 89 degrees.

Operating and Programming Guide 5-17

Chapter 5 Command Reference

GPS Satellite Acquisition

Selecting Satellites _____________________________

59551A

:GPS:SATellite:TRACking:IGNore . . .

Adds the specified satellites to the list that the Receiver ignores for tracking.

(continued)

:SYSTem:PRESet

No satellites ignored

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

:GPS:SATellite:TRACking:IGNore?

Returns list of satellites to ignore.

RESPONSE FORMAT

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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Selecting Satellites _____________________________

59551A

:GPS:SATellite:TRACking:INCLude . . .

Adds the specified satellites to the list that the Receiver considers for tracking.

(continued)

:SYSTem:PRESet

All satellites included

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

:GPS:SATellite:TRACking:INCLude?

Returns a list of satellites to include.

RESPONSE FORMAT

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______________________________

:GPS:SATellite:TRACking:IGNore:COUNt?

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

(continued)

RESPONSE FORMAT

: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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Selecting Satellites______________________________

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

Returns the ignored status of individual satellites.

(continued)

RESPONSE FORMAT

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.

Operating and Programming Guide 5-21

Chapter 5 Command Reference

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Compensating for Antenna Delay_________________________

:GPS:REFerence:ADELay . . .

Sets the GPS antenna delay value in seconds.

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.

:SYSTem:PRESet

0.0

NON-VOLATILE

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