Symmetricom Z3801A User Manual

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Z3801A

GPS Receiver

097-Z3801-01

Issue 1: May 00

User’s Guide

This guide describes how to install and operate the Z3801A GPS Receiver. 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: 3506A and above

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

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.

Indicates hazardous voltages.

Indicates earth (ground) terminal.

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

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

Indicates Alternating current.

Indicates Direct current.

In This Guide

Guide Organization..................................................................... vii

Description of the Z3801A GPS Receiver .............................. viii

Options ............................................................................................. ix

Accessories Supplied and Available.......................................... ix

Accessories Supplied ................................................................... ix

Accessories Available .................................................................. ix

Manuals............................................................................................xi

Supplied Manual ......................................................................... xi

Available Documents .................................................................. xi

1Getting Started

Z3801A Front Panel at a Glance ............................................... 1-2

Z3801A Rear Panel at a Glance ............................................... 1-3

Preparing the GPS Receiver for Use ...................................... 1-4

To Assemble and Install the Antenna System ........................ 1-4

To Assemble the DC Power Connector..................................... 1-5

Powering Up the Receiver......................................................... 1-6

Overview of the Power-Up Procedure (What to Expect) ......... 1-6

To Power Up the Receiver......................................................... 1-6

To Understand the Receiver Status Screen Data.................. 1-10

Installing the Automated SatStat Program for Continual

Status Updates ........................................................................... 1-11

Operating the Automated SatStat Program........................ 1-12

Customizing the Receiver Operation ................................... 1-13

Using Commands to Control Key Functions (Examples). 1-14

To Perform Basic Installation and Simple Customizing....... 1-14

If required, restore all of the Receiver’s internal settings to their factory shipment values by invoking a system

preset.................................................................................. 1-14

Initiate “surveying”, an automatic determination of the

Receiver’s antenna position. ............................................. 1-15

Set the Receiver to compensate for the length of the antenna

cable. .................................................................................. 1-15

Set the Receiver to exclude satellites which appear below a

specified elevation angle. .................................................. 1-16

Set the Receiver to display local time rather than

UTC time. .......................................................................... 1-16

To Install With a Limited View of the Sky, To Bypass Position

Survey Operation .................................................................... 1-16

User Guide iii

Contents

2 Features and Functions

Chapter Contents ........................................................................ 2-2

Inputs ............................................................................................. 2-3

ANTENNA Input ...................................................................... 2-3

Recommended Antenna Cable Assemblies ........................2-3

Antenna Cable Length Delay ............................................. 2-5

DC INPUT J4 Power Jack ........................................................ 2-6

Outputs .......................................................................................... 2-7

10 MHz OUT J2 Output ........................................................... 2-7

10 MHz Outputs—via I/O Port 1 J3......................................... 2-7

1 PPS (One Pulse Per Second) Outputs—via I/O Port 1 J3 .... 2-7

RS-422 Serial Port, I/O Port 1 J3 ............................................. 2-8

Indicators ...................................................................................... 2-9

Power Indicator ......................................................................... 2-9

Enabled/Active Indicator .......................................................... 2-9

Alarm Indicator ......................................................................... 2-9

GPS Lock Indicator ................................................................... 2-9

Holdover Indicator .................................................................... 2-9

Connecting to a Computer ...................................................... 2-10

Operating Concepts .................................................................. 2-11

General .................................................................................... 2-11

Holdover Description .............................................................. 2-11

In Case of a Problem ................................................................. 2-12

Hours after powerup, Receiver not establishing GPS lock ... 2-12

Receiver not maintaining GPS lock ....................................... 2-13

3 Using the Receiver Status Screen

Chapter Contents ........................................................................ 3-2

Using and Reading the Receiver Status Screen ................... 3-3

Tutorial on Using the Status Screen to Interface With the

Receiver...................................................................................... 3-4

Demonstration of Holdover Operation ..................................... 3-8

Receiver Status Screen Data .................................................. 3-11

SYNCHRONIZATION Section of the Status Screen............. 3-12

SYNCHRONIZATION Summary Line ............................ 3-12

SmartClock Mode .............................................................. 3-12

Reference Outputs ............................................................. 3-13

ACQUISITION Section of the Status Screen ........................ 3-14

ACQUISITION Line.......................................................... 3-14

Tracking, Not Tracking..................................................... 3-15

Time ................................................................................... 3-16

iv User Guide

Contents

Position .............................................................................. 3-17

HEALTH MONITOR Section of the Screen...........................3-18

The Receiver Status Screen at a Glance .............................. 3-19

4 Command Listing and Status Information

Chapter Contents ........................................................................ 4-2

Z3801A Commands ...................................................................... 4-3

SCPI Conformance Information ............................................... 4-3

SCPI Syntax Conventions......................................................... 4-3

Description of Commands ......................................................... 4-3

Detailed Description of the Two Time Code Formats ........... 4-12

Status Information .................................................................... 4-14

Standard Event Register Bit Assignments............................ 4-14

Questionable Status Register Bit Assignments .................... 4-15

Operation Status Register Bit Assignments.......................... 4-15

Powerup Status Register Bit Assignments ............................ 4-16

Holdover Status Register Bit Assignments ........................... 4-16

Hardware Status Register Bit Assignments ......................... 4-17

Information that Appears in the Diagnostic Log............... 4-18

Model for Powerup, Locked, and Holdover States ............ 4-19

Error Messages........................................................................... 4-21

5 Specifications Summary

Specifications and Characteristics ......................................... 5-2

GPS Receiver Features ............................................................. 5-2

10 MHz Output Characteristics ............................................... 5-2

J2................................................................................................ 5-2

1 PPS Output Characteristics .................................................. 5-3

Front Panel Indicators (LEDs) ................................................. 5-3

Remote Interface (Port 1).......................................................... 5-3

Antenna and Cabling Information ........................................... 5-3

Environmental........................................................................... 5-4

58504A Antenna Assembly................................................. 5-4

GPS Time and Frequency Reference Receiver .................. 5-4

Power Requirements ................................................................. 5-4

General Information ................................................................. 5-4

Other Information ..................................................................... 5-4

Index

User Guide v

Contents

vi User Guide

In This Guide

This preface contains the following information:

• Guide Organization page vii

• Description of the Z3801A GPS Receiver page viii

• Options page ix

• Accessories Supplied and Available page ix

• Manuals page xi

Guide Organization

Table of Contents

In This Guide (this preface) introduces you to the User’s Guide, and

provides general information on the GPS Receiver.

Chapter 1, “Getting Started,” is a quick-start chapter that introduces you to the GPS Receiver with a brief overview of the Receiver’s indicators and connectors. Installation and power-up instructions, and a section that provides sample commands to start operating the Receiver are provided to get you familiar and comfortable with operating the Receiver.

Chapter 2, “Features and Functions,” provides information on Receiver’s features and functions, connecting to computers, and problem solving (that is, a section titled “In Case of a Problem”).

Chapter 3, “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 Listing and Status Information,” briefly lists all of the commands that can be used to operate the Receiver and provides Receiver status and error message information.

Chapter 5, “Specifications Summary,” lists the Z3801A specifications and characteristics.

Index

User Guide vii

In This Guide

Description of the Z3801A GPS Receiver

The Z3801A GPS Receiver provides highly accurate time and frequency outputs that can be used for synchronizing CDMA Cellular Land Network wireless base stations.

The Receiver provides highly accurate timing. If a satellite signal is lost, the Receiver automatically switches to holdover mode, which ensures system synchronization for up to 24 hours with reduced accuracy.

The Z3801A has the following rear-panel Input/Output connectors:

• an I/O Port 1 25-pin female rectangular D subminiature connector (This connector provides two 1 PPS time outputs, two 10 MHz frequency outputs, and an RS-422 serial interface port).

• 10 MHz output BNC connector

• an Antenna N-type connector

• Power input jack

The front panel contains six Light-Emitting-Diode (LED) indicators to indicate that power has been applied (Power), the module has tracked and locked on to one or more GPS satellites (GPS Lock), the GPS system is operating in holdover mode (Holdover), and an error or invalid condition exists due to system fault or reduced accuracy of the outputs (Alarm), and two LEDs illuminated under user-defined conditions (Enabled, Active).

The Z3801A has no front panel display or keypad entry. Information is remotely entered into and retrieved from the Z3801A using customersupplied DCE (Digital Communications Equipment) connected to the rear-panel 25-pin RS-422 serial interface port.

viii User Guide

In This Guide

Options

• Rack Mount Tray 29.5 inch (750-millimeter)

• CV90-14271-1 GPS Receiver Unit, +27 Vdc, beige, single output

• CV90-14271-2 GPS Receiver Unit, --54 Vdc, beige, single output

• CV90-14271-11 GPS Receiver Unit, -+27 Vdc, gray, single output

• CV90-14271-12 GPS Receiver Unit, --54 Vdc, gray, single output

• CV90-15357-1 GPS Receiver Unit, +27 Vdc, beige, single output

• CV90-15357-2 GPS Receiver Unit, --54 Vdc, beige, single output

• CV90-14805-1 Shelf, Dual GPS Receiver Mounting, beige

• CV90-14805-11 Shelf, Dual GPS Receiver Mounting, gray

Accessories Supplied and Available

Accessories Supplied

SatStat Program (59551-13401)

Accessories Available

For more details on available GPS accessories refer to the Designing Your GPS Antenna System Configuration Guide (P/N 5964-9068E).

Refer to the subsections titled “Recommended Antenna Cable Assemblies” and “Antenna Cable Length Delay” in Chapter 2 of this guide for more cable information.

• CV90-14807 Coaxial cables

• CE90-14806 Antenna, GPS Receiver

• CE90-15275 Lightning Arrestor, GPS Receiver

• CE90-15276 Line Amplifier, GPS Receiver

• 58504A GPS Antenna Assembly

• 58510A GPS Antenna Environmental Cover and Ground Plane (optional use with the 58504A GPS Antenna Assembly)

• 58513A GPS Antenna Assembly

• 58505B Lightning Arrester

• 58509A Antenna Line Amplifier (recommended for distances greater than 175ft./53.3 meters for RG-213 cable; 200 ft/61 meters for LMR cable)

User Guide ix

In This Guide

• 58518A RG-213 Antenna Cable Assembly (3.3 to 164.0 ft, or 1 to 50 meters)—TNC-to-N connectors

• 58519A RG-213 Interconnect Cable Assembly (3.3 to 164.0 ft, or 1 to 50 meters)—N-to-N connectors

• 58520A LMR 400

Antenna Cable Assembly (3.3 to 360.8 ft, or

1 to 110 meters)—TNC-to-N connectors

• 58521A LMR 400

Interconnect Cable Assembly (3.3 to 360.8 ft, or

1 to 110 meters)—N-to-N connectors

• 58518AA

RG-213 TNC-N Antenna Cable Assembly

(3.3 to 164.0 ft, or 1 to 50 meters) without connectors attached

• 58519AA

RG-213 N-N Interconnect Cable Assembly

(3.3 to 164.0 ft, or 1 to 50 meters)—without connectors attached

• 58520AA

LMR 4002 TNC-N Antenna Cable Assembly

(3.3 to 360.8 ft, or 1 to 110 meters)—without connectors attached

• 58521AA

LMR 4002 N-N Interconnect Cable Assembly

(3.3 to 360.8 ft, or 1 to 110 meters)—without connectors attached

The 58513A is a completely assembled unit, which includes the 58504A Antenna, a 4-foot cable, the 58510A environmental cover and ground plane, and a 1-foot stainless steel mounting mast.

LMR 400 cables are low-loss, less flexible than RG-213, but are very good coaxial cables.

These cables do not have the connectors attached. A connector kit is supplied.

xUser Guide

In This Guide

Manuals

Supplied Manual

Z3801A User’s Guide (this guide), P/N Z3801-01

User Guide xi

In This Guide

xii User Guide

Getting Started

Chapter 1 Getting Started

Z3801A Front Panel at a Glance

I N C O R P O R A T E D

Power

Enabled Active

123 45

1 When the Power indicator is illuminated, it

indicates that the proper input power is supplied to the Receiver.

2 User-definable indicators labeled Enabled and

Active. These can be turned on through the

RS-422 port.

3 When the Alarm indicator is illuminated, it

indicates that the receiver has detected an internal condition that requires attention.

GPS RECEIVER

Alarm

GPS Lock

4 When the GPS Lock indicator is illuminated, it

indicates that the Receiver is receiving the GPS signal and is locked on one or more satellite(s).

5 When the Holdover indicator is illuminated, 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. (See specification for Accuracy in Holdover in Chapter 5, “Specifications Summary,” in this guide.)

Holdover

1-2 User Guide

Chapter 1 Getting Started

Z3801A Rear Panel at a Glance

ANTENNA

J1 J2

I/O

Port 1

10 MHz OUT

SERIAL PLATE

Made in U.S.A. with domestic and foreign content.

NRTL/C TESTED TO UL 1950

WARNING:

To avoid electric shock: Do not remove covers. No user serviceable parts inside. Refer all servicing to qualified personnel. This unit must be earth grounded.

CAUTION

METRIC & INCH HARDWARE CONSULT SERVICE MANUAL

DC INPUT

BTS

CV90 - 15357 - 1

19.5 - 30VDC

BSC

CV90 - 15357 - 2

38 - 60VDC

1 ANTENNA J1 N-type (female) connector.

2 10 MHz OUT J2 BNC (female) output connector

for user-specific applications.

3 DC INPUT J4 power connector.

User Guide 1-3

4 I/O Port 1 J3 25-pin female D Subminiature

RS-422 serial interface port for remote control, monitoring, and retrieving of the unit’s memory data. This port also provides two 1 PPS time outputs, and two 10 MHz frequency outputs.

5 E1 Ground stud provides a low impedance

ground for safety and systems grounding. WARNING: Ground stud must be connected to Safety Earth Ground.

Chapter 1 Getting Started

Preparing the GPS Receiver for Use

To Assemble and Install the Antenna System

CABLE CONSIDERATIONS. When using the antenna cables with the GPS Receiver, you should observe certain precautions. Consult your local electrical and building ordinance codes on how to install RG-213 cables (58518A/519A) or LMR 400 cables (58520A/521A). Certain codes might require you to put the cables inside a conduit, or to use cables made with a non-toxic fire retardant insulation.

To assist you with installing your GPS antenna system, refer to the following documents:

• Information Notes that provide installation procedures for the applicable GPS antenna and accessories that you purchase.

• The subsection titled “ANTENNA Input” in Chapter 2, “Features and Functions,” of this guide.

To Assemble the DC Power Connector

1 Note that you will have to assemble your own dc power cable using

18 AWG connecting wires and a three-pin AMP Universal MATE-N-LOKII® (female) connector plug (shown in Figure 1-1).

1 dc supply (+)

3 dc supply (-)

2 Not used

Figure 1-1. Three-Pin Plug Pinouts (Front View)

2 From the rear of the plug, connect the supply-side wire of the external

power supply or battery to pin 1 of the plug. Connect the external

1-4 User Guide

4 Cable wires

Chapter 1 Getting Started

Preparing the GPS Receiver for Use

battery’s return (ground) wire to pin 3. Use the rear-panel E1 ground stud to connect the GPS Receiver chassis to a system ground.

3 Observing the correct polarity, attach the other ends of the wires to a

proper dc power source to operate the Receiver.

NOTE Do not apply power to the Receiver unless a fully operational antenna

system is connected to the rear-panel ANTENNA J1 connector. Power applied with no antenna input can initiate an extended search process that may increase time to reach GPS lock. You can halt the extended search by disconnecting and reconnecting (cycling) the external dc supply (you may need to leave power disconnected for greater than five seconds).

User Guide 1-5

Chapter 1 Getting Started

Powering Up the Receiver

Overview of the Power-Up Procedure (What to Expect)

When you power up the GPS Receiver for the first time, you should expect it to run through the following sequence:

• goes through internal diagnostics and all front-panel lights flash,

• acquires and tracks four satellites,

• computes the Receiver’s position,

• locks to the 1 PPS (one pulse-per-second) time standard provided by GPS, and

• begins steady-state operation, acting as a source of timing and synchronization information derived from the GPS standard.

Elapsed time for each step will vary, depending largely on how many satellites your antenna is able to “see” when you power up. If many satellites are visible when you power up, the Receiver will take at least 8 minutes and at most 25 minutes to calculate its position from the constellation of satellites overhead. The derived position will be improved over a period of time by further averaging. When the GPS Lock indicator lights, the basic functionality of the Receiver is available; however, optimal performance is delivered later.

To Power Up the Receiver

1 Connect the antenna system to the rear-panel ANTENNA J1 Type-N

connector of the Receiver as described in the instructions given in the subsection titled “To Assemble and Install the Antenna System” on page 1-4 of this chapter.

NOTE Although connecting the GPS Receiver to a terminal or computer isn’t

necessary for it to attain GPS lock, the terminal is needed for you to observe the progress of the Receiver or to configure alarms.

2 Connect the GPS Receiver to your system DCE device (Digital

Communications Equipment) via the rear-panel I/O Port 1 J3 RS-422 port using an appropriate (customer supplied) system interface cable as shown in Figure 1-2.

1-6 User Guide

Chapter 1 Getting Started

Powering Up the Receiver

NOTE Do not apply power to the Receiver unless a fully operational antenna

GPS Receiver (Rear view)

DCE Device

Figure 1-2. Connecting the GPS Receiver to a DCE Device (DTE-to-DCE Interface cable is customer supplied)

3 Turn your DCE device (or PC equipped with a correctly wired RS-422

serial-port connector) on.

You will need to run a terminal emulation program on your DCE device in order to communicate via the RS-422 serial port. Most PCs contain a

terminal emulation program, especially PCs with Windows application. If your PC does not contain a terminal emulation program, purchase one of the following programs: PROCOMM PLUS (DATASTORM Technologies, Inc.®), PROCOMM PLUS for Windows, Cross Talk (Hayes®), or any other terminal emulation program. (Note: Symmetricom is not endorsing any of these products.)

Another option to purchasing and installing a terminal emulation program is to use the SatStat Program. See the section titled “Installing the Automated SatStat Program for Continual Status Updates” on page 1-11 for installation and operating information.

User Guide 1-7

Chapter 1 Getting Started

Powering Up the Receiver

4 Set the RS-422 port of your DCE device (or PC) to match the following

values:

Pace: NONE

Baud Rate: 19200

Parity: Odd

Data Bits: 7/char

Start Bits: 1

Stop Bits: 1

NOTE The RS-422 port configurations of the Receiver and the DCE device/PC

must be the same for communications between the two. Thus, for this power-up procedure, set your DCE device/PC to match the default values listed above.

5 Apply the proper power source to the rear-panel Power input jack of the

Receiver. (See the appropriate subsection titled “To Assemble the DC Power Connector” on page 1-4)

The following sequence of events occurs after power is applied to the Receiver.

a. Only the front-panel Power indicator lights.

b. After a moment, the Receiver runs through its self-test diagnostics

as indicated by the flashing front-panel indicators.

c. After the self test is completed, just the Power indicator remains lit.

If the Alarm indicator lights, a failure may have occurred during the self test. Refer to Table 4-2 in Chapter 4, “Command Listing and Status Information,” of this guide for information on the Alarm capability.

d. The Receiver begins to search the sky for all available satellites.

1-8 User Guide

Chapter 1 Getting Started

Powering Up the Receiver

e. From the DCE device keyboard, type

:SYSTEM:STATUS? and press Enter (or Return).

Confirm that the scpi> prompt is displayed after pressing Return. If no prompt or an error-number prompt (E-xxx>) is displayed, then try typing the command again.

The computer displays the status screen as shown in the sample status screen in Figure 1-3.

You must re-enter the :SYSTEM:STATUS? command each time you want an updated status screen.

NOTE You have been provided a Windows program called SatStat, which

provides continual status updates of the GPS Receiver’s status screen. If you are using an RS-422 equipped PC, it must have Windows installed to operate the user interface application. The application is easy to install and operate.

See the section titled “Installing the Automated SatStat Program for Continual Status Updates” on page 1 in this guide.

f. When four or more satellites are tracked as will be indicated in the

status screen, automatic position computation is initiated.

g. Finally, the Receiver goes into steady-state operation (which

requires one satellite) and the GPS Lock indicator lights, indicating the Receiver has locked on to the GPS signal.

After the initial powerup, the Receiver is set for basic operation. That is, the Receiver operating parameters are set to their powerup default values or states.

If you need to customize the Receiver operation, see the section titled “Customizing the Receiver Operation” on page 1-13 for a list of key things you may want to perform to customize the operating parameters of the Receiver.

User Guide 1-9

Chapter 1 Getting Started

Powering Up the Receiver

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

SYNCHRONIZATION SmartClock Mode

Locked to GPS: stabilizing frequency...

Recovery Holdover Power-up

ACQUISITION Satellite Status

Tracking: 5 PRN El Az

ELEV MASK HEALTH MONITOR

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

337

188

113

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

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

Not Tracking: 4 PRN

SS 134 117

29 128

12 11 292 16 24 243

*26 Acq..

31 -- ---

*attempting to track

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

Receiver Status

[

Outputs Valid/Reduced Accura Reference Outputs TFOM FFOM

1PPS TI HOLD THR

Time GPS 1PPS CLK Synchronized to GPS Ti ANT DLY

Position MODE

AVG LAT AVG LON AVG HGT

3 0

+20 ns relative to GPS

1.000 us

[GPS 1PPS CLK Accurate]

03:56:44 1994 DEC 01

120 ns

Survey: 57.3% complete

NW37:19:31.330

121:59:50.468

+54.89 m (MSL)

cy ]

[ OK ]

Figure 1-3. Sample Status Screen

To Understand the Receiver Status Screen Data

One of the key indicators on the screen is the ACQUISITION status indicator. It shows “GPS 1 PPS Valid ” as soon as satellite information is sufficient.

Refer to Chapter 3, “Using the Receiver Status Screen,” in this guide for a tutorial on how to use the status screen (shown in Figure 1-3). A reference section that defines the different data indicated in the status screen is also provided in Chapter 3.

1-10 User Guide

Chapter 1 Getting Started

Installing the Automated SatStat Program for Continual Status

Updates

Installing the Automated SatStat Program for Continual Status Updates

This Windows application provides continual status updates of the Receiver Status screen. Your PC must be equipped with a correctly wired (See Table 2-3 in Chapter 2.) RS-422 serial-port adapter and have Windows installed to operate the user interface application. The application is easy to install and operate.

1 Insert the SatStat disk in drive A.

2 From the File menu in either the Program Manager or File Manager,

choose Run.

3 Type a:setup, and press Enter (or Return). The SatStat Setup screen

will appear, and installation will proceed.

4 Once the program is installed, you can start it by double-clicking the

SatStat icon that was created during the installation.

5 You should establish communication with the GPS Receiver.

This requires connection from the DCE device (Digital Communications Equipment) via the rear-panel I/O Port 1 J3 RS-422 port using an appropriate (customer supplied) system interface cable. Assuming you’ve got the cable attached to make this connection, you may want to check the settings.

a. Select CommPort, then choose Settings.

The Communication Settings dialog box is displayed. Unless someone has reprogrammed the CommPort settings on the GPS Receiver, these settings are probably OK. The one setting that

is likely to need changing is the Com Port. The application defaults it to Com1, but the serial port on your PC may be assigned to a different Com Port. Select the appropriate setting. If you are unsure, Com1 will be your best bet (worst case, you can cycle through all of them until it works).

b. If you made any changes on this Settings form, select OK,

otherwise you can just Cancel.

User Guide 1-11

Chapter 1 Getting Started

Operating the Automated SatStat Program

1 Select CommPort, then choose Port Open.

The main form of the Receiver Status screen is displayed. The program will send some commands to the GPS Receiver and then the main form should begin to periodically update every few seconds. If you are getting screen updates, proceed to the next step. Otherwise, something is wrong with your CommPort settings or perhaps the physical connection between your PC and the Receiver.

If you need to control the Receiver or query for the status of a setting of the Receiver, use the “Control & Query” form (this form will usually be stacked beneath the main form). To activate this form, click anywhere on it. Select Control (or Query), then choose the type of control (or query) you want. This will pull down a list of control (or query) functions that you can choose from, and the corresponding command will be displayed. To send the command, click on Send Cmd. Hence, with the Control & Query form you can control the Receiver without knowing the command or query.

More information about the Windows program is provided in the “Getting Started” Help file.

2 Refer to the section titled “Using and Reading the Receiver Status

Screen” in Chapter 3, “Using the Receiver Status Screen,” of this guide for a tutorial and demonstration of what to look for when viewing the status screen.

1-12 User Guide

Chapter 1 Getting Started

Customizing the Receiver Operation

Here are some key things you might want to perform to customize the Receiver operation:

• Execute a system preset if you've found the Receiver in an unknown or questionable operating state.

• Make the Receiver survey if it wasn’t already surveying.

• Set the antenna delay.

• Set the elevation mask angle.

• Set the time zone.

See the section titled “Using Commands to Control Key Functions (Examples)” on the following page for more information.

User Guide 1-13

Chapter 1 Getting Started

Using Commands to Control Key Functions (Examples)

The operation of the GPS Receiver is designed to be as automatic as possible. However, there are several situations where serial interface control is required. The tasks described here are those most commonly encountered.

For each task in this section, you can use either a terminal emulation program or the SatStat program to issue the selected commands. Additional information about the commands is provided in Chapter 4, “Command Listing and Status Information,” of this guide.

To Perform Basic Installation and Simple Customizing

After connecting the Receiver to the antenna, power source, DCE device RS-422 port, and after the self test is completed, you may want to complete installation using one or more of the capabilities described below.

If required, restore all of the Receiver’s internal settings to their factory shipment values by invoking a system preset.

After executing the system preset, the Receiver will begin normal operation: it will acquire GPS signals, determine the date, time, and position automatically, bring the reference oscillator ovens to a stable operating temperature, lock the reference oscillator and its output to 10 MHz, and synchronize the 1 PPS output to UTC.

Settings affected by system preset are listed in Chapter 4, “Command Listing and Status Information,” of this guide under the :SYSTEM:PRESET command definition.

The Receiver is preset using the command:

:SYSTEM:PRESET

Note that system preset should be performed only when necessary.

1-14 User Guide

Chapter 1 Getting Started

Using Commands to Control Key Functions (Examples)

Initiate “surveying”, an automatic determination of the Receiver’s antenna position.

When “position survey” is invoked, the Receiver is set to ascertain the position of its antenna automatically. This survey is important; correct antenna position data is required for the Receiver to deliver specified performance.

The Receiver uses data from orbiting satellites to survey; hence, the antenna must be installed and operational for the survey to work. However, if you have a limited view of the sky, you can complete basic installation, then read forward to the section titled “To Install With a Limited View of the Sky, To Bypass Position Survey Operation” on page 1-16 for a means of overriding the survey operation and entering position data directly.

The survey is an iterative process. The Receiver transits to “Position Hold” when a usable position has been obtained.

Set the Receiver to survey using command:

:PTIME:GPSYSTEM:POSITION:SURVEY ONCE

Set the Receiver to compensate for the length of the antenna cable.

The Receiver can be custom-configured to compensate for the length of the antenna cable. The phase of the Receiver’s internal clock is therefore offset from the GPS standard by the number of nanoseconds of delay introduced through the antenna cable. The amount of error is typically on the order of a few hundred nanoseconds. Should you decide to correct for this error, Table 2-1A and Table 2-1B in Chapter 2, “Features and Functions,” of this guide provides typical corrections for standard antenna cable lengths.

Set the Receiver to compensate for antenna cable delay using command:

:PTIME:GPSYSTEM:ADELAY <seconds>

:PTIME:GPSYSTEM:ADELAY <nanoseconds> NS

It is normal to observe that the Receiver momentarily goes into holdover after any change in antenna delay.

User Guide 1-15

Chapter 1 Getting Started

Using Commands to Control Key Functions (Examples)

Set the Receiver to exclude satellites which appear below a specified elevation angle.

At the factory, and whenever the Receiver is preset, the Receiver is set to seek satellites visible from zenith down to 10 degrees above the horizon—down to an “elevation mask angle” of 10 degrees. The factory elevation mask angle setting is intended to provide a full view of the sky. The Receiver can be custom-configured to use a different elevation mask angle.

Set the Receiver elevation mask angle using the command:

:PTIME:GPSYSTEM:EMANGLE <degrees>

Set the Receiver to display local time rather than UTC time.

Set the offset from UTC time to local time using the command:

:PTIME:TZONE <hours>, <minutes>

To Install With a Limited View of the Sky, To Bypass Position Survey Operation

In order to reach steady-state operation, the Receiver must know the position of the antenna. The Receiver is able to collect enough information from four satellites to compute this position. The “position survey operation” takes in data from the satellites, iterating until the antenna position is known to the required precision. The Receiver will automatically use its position survey operation on powerup and :SYSTEM:PRESET.

Alternatively, if the antenna position is already known to seconds of arc, and the Receiver cannot see enough satellites, you may manually enter antenna position as shown in the following text.

NOTE An incorrect value for the position will confuse the Receiver, and will

degrade the timing information accuracy or even prevent tracking any satellites.

Set the Receiver antenna position using the command format shown below (for clarity, an example is provided rather than a complex description.):

:PTIM:GPS:POS N,37,19,32.5,W,121,59,51.2,40.12

1-16 User Guide

Chapter 1 Getting Started

Using Commands to Control Key Functions (Examples)

Set the latitude, longitude, and height parameters to represent the latitude (in degrees, minutes, seconds), longitude (in degrees, minutes, seconds), and altitude in meters above mean sea level (MSL). (Note: if you know the position to this accuracy, the desired position is of the antenna rather than the Receiver.)

NOTE For faster acquisition following repair, or power failure you may want

to write down the position after the Receiver has completed its survey.

User Guide 1-17

Chapter 1 Getting Started

Using Commands to Control Key Functions (Examples)

1-18 User Guide

Features and Functions

Chapter 2 Features and Functions

Chapter Contents

You will find that this section makes it easy to look up all the details about a particular feature of the Z3801A GPS Receiver. This chapter provides inputs, outputs, indicators, terminal and computer connections, operating concepts (GPS lock and holdover), and problem-solving information.

This chapter is organized as follows:

• Inputs page 2-3

– ANTENNA Input page 2-3

– DC INPUT J4 Power Jack page 2-6

• Outputs page 2-7

– 10 MHz OUT J2 Output page 2-7

– 10 MHz Outputs—via I/O Port 1 J3 page 2-7

– 1 PPS (One Pulse Per Second) Outputs— via I/O

Port 1 J3

– RS-422 Serial Port, I/O Port 1 J3 page 2-8

• Indicators page 2-9

– Power Indicator page 2-9

– Enabled/Active Indicator page 2-9

– Alarm Indicator page 2-9

– GPS Lock Indicator page 2-9

–Holdover Indicator page2-9

• Connecting to a Computer page 2-10

• Operating Concepts page 2-11

– General page 2-11

– Holdover Description page 2-11

• In Case of a Problem page 2-12

page 2-7

2-2 User Guide

Chapter 2 Features and Functions

Inputs

ANTENNA Input

The N-type (female) ANTENNA connector allows you to connect the 58504A or 58513A Antenna Assembly. The antenna assemblies are “active” antennas; a “passive” antenna will not work with the Receiver.

Integral to the antenna assembly is a low noise amplifier (LNA) that is provided for Receiver operation with antenna cable lengths up to 378 feet (115.2 meters) for LMR 400 cables or 175 feet for RG-213 cables. The single coax cable is used to provide signals from the antenna to the Receiver and to supply a dc voltage to the LNA. For longer antenna feed runs, an additional amplifier (58509A Antenna Line Amplifier) is required to compensate for lengths greater than 378 feet (115.2 meters) or 175 feet (53.3 meters). An environmental cover that shields the antenna from wind, rain, and snow, and a ground plane that prevents problems with reflected signals is available as the 58510A—or combined in the 58513A.

(53.3 meters)

Refer to Chapter 1, “Getting Started,” in this guide for information on the components of the antenna system and installation instructions.

Recommended Antenna Cable Assemblies

There are two types of cable assemblies that we recommend you use to connect your antenna system: LMR 400 or RG-213 (Belden® 8267).

The following paragraphs describes when and how many line amplifiers are required with the LMR 400 and RG-213 cables.

One hundred and seventy-five feet includes the sum total of all of the cables used to connect the antenna to the (such as the cable between the antenna and line amplifier, the cable between the line amplifier and lightning arrester, and the cable between the lightning arrester and the ).

User Guide 2-3

Chapter 2 Features and Functions

Inputs

LMR 400 Cable Line Amplifier Requirements

If cable length between GPS Receiver and antenna is:

• Less than 115 meters (377 feet), no line amplifier is necessary.

• More than 115 meters (377 feet) and less than 240 meters (787 feet), you need 1 line amplifier.

• More than 240 meters (787 feet) and less than 360 meters (1181 feet), you need 2 line amplifiers.

• More than 360 meters (1181 feet), contact sales/support for assistance.

RG-213 Cable Line Amplifier Requirements

If cable length between GPS Receiver and antenna is:

• Less than 53 meters (174 feet), no line amplifier is necessary.

• More than 53 meters (174 feet) and less than 105 meters (345 feet), you need 1 line amplifier.

• More than 105 meters (345 feet) and less than 158 meters (518 feet), you need 2 line amplifiers.

• More than 158 meters (518 feet), contact sales/support for assistance.

2-4 User Guide

Chapter 2 Features and Functions

Inputs

Antenna Cable Length Delay

The RG 213 propagation delay is 1.54 nanoseconds per foot (5.05 ns/meter). The LMR 400 propagation delay is 1.2 nanoseconds per foot (3.93 µs/meter). Given these delay values per foot you can calculate the delay for your cable length.

Tables 2-1A and 2-1B list the delay values that you need to use with the :GPSYSTEM:REFERENCE:ADELAY <seconds> command for the available the cable assemblies.

Table 2-1A. Delay Values for the 58518A/519A and 58518AA/519AA RG-213 Antenna Cables

Cable Option Length RG 213 or Belden 8267

Antenna Delay Value

001 3.3 ft (1m) 5.0 nanoseconds

002 6.7 ft (2 m) 10.3 nanoseconds

005 16.4 ft (5 m) 25.2 nanoseconds

010 32.8 ft (10 m) 50.5 nanoseconds

015 49.2 ft (15 m) 75.7 nanoseconds

030 98.4 ft (30 m) 151.5 nanoseconds

050 164.0 ft (50 m) 252.5 nanoseconds

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

Designing Your GPS Antenna System Configuration Guide

(P/N 5964-9068E for more information.)

User Guide 2-5

Chapter 2 Features and Functions

Inputs

Table 2-1B. Delay Values for the 58520A/521A and 58520AA/521A LMR 400 Antenna Cables

Cable Option Length LMR 400 Antenna Delay

Value

001 3.3 ft (1m) 3.9 nanoseconds

002 6.7 ft (2 m) 8.0 nanoseconds

005 16.4 ft (5 m) 19.6 nanoseconds

010 32.8 ft (10 m) 39.3 nanoseconds

015 49.2 ft (15 m) 59.0 nanoseconds

030 98.4 ft (30 m) 118.0 nanoseconds

060 196.8 ft (60 m) 236.1 nanoseconds

110 360.8 ft. (110 m) 432.9 nanoseconds

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

Designing Your GPS Antenna System Configuration Guide

(P/N 5964-9068E for more information.)

DC INPUT J4 Power Jack

The DC INPUT J4 jack allows you to connect a BTS 19.5-30.0 Vdc or BSC -38 to -60 Vdc power source to drive the Receiver.

Table 2-2 lists the input jack pin assignments. This jack is used for DC power only.

Table 2-2. DC INPUT J4 Power Connections

Pin Number Signal Name

1 dc supply (+)

3 dc return (−)

See Figure 1-1 in Chapter 1, “Getting Started,” in this guide for an illustration of the AMP Universal MATE-N-LOKII® dc power jack.

2-6 User Guide

Chapter 2 Features and Functions

Outputs

10 MHz OUT J2 Output

This is a 10 MHz output reference signal traceable to UTC (USNO) that can be used for synchronizing CDMA test equipment.

10 MHz Outputs—via I/O Port 1 J3

Two additional 10 MHz synchronization signals are available through the I/O Port 1 J3 connector. Refer to Table 2-3 for signal characteristics and connector pin assignment information.

1 PPS (One Pulse Per Second) Outputs— via I/O Port 1 J3

The Receiver outputs two highly accurate 1 PPS time standard outputs for user-specific synchronization applications. Refer to Table 2-3 for signal characteristics and connector pin assignment information.

In the GPS locked mode, the Receiver outputs a 1 PPS signal derived from the internal oscillator, which is locked and traceable back to Coordinated Universal Time (UTC) as determined by GPS. In the absence of GPS, the 1 PPS signal will continue to exist, but the oscillator will go into a holdover mode in which the SmartClock™ algorithm will compensate for the instabilities in the oscillator. In the holdover mode, the timing 1 PPS accuracy will degrade as the holdover time increases.

User Guide 2-7

Chapter 2 Features and Functions

Outputs

RS-422 Serial Port, I/O Port 1 J3

The 25-pin female D Subminiature (DB-25) connector located on the rear panel provides RS-422 serial communications capability.

This can be used by connecting a DCE device with an RS-422 serial interface port (wired to interface with the receiver's I/O port as listed in Table 2-3) and suitable terminal emulation software, then sending the correct commands for transmitting or retrieving data. You can customize the Receiver on installation, to change the Receiver’s operating characteristics, retrieve Receiver state information, and clear the stored data. The pins used are described in Table 2-3.

Table 2-3. Rear-Panel RS-422 Serial Port/10 MHz/1PPS Pin Assignments

*Pin Number Input/Output Description

1 Cable Shield

2 (A),

14 (B)

3 (A),

16 (B)

7 ——— Signal Ground (SG)

*All other pins, no connection.

Output Transmit Data (TxD)—GPS Receiver

output RS-422 (per RS-530)

Input Receive Data (RxD)—GPS Receiver

input RS-422 (per RS-530)

10 MHz_1-

10 MHz_1+

10 MHz_2-

10 MHz_2+

1 PPS/_1-

1 PPS/_1+-

1 PPS/_2-

1 PPS/_2+

Differential pseudo ECL 10 MHz output

Differential pseudo ECL 1 PPS output

2-8 User Guide

Chapter 2 Features and Functions

Indicators

Power Indicator

This indicator lights when the input power is supplied to the Receiver.

Enabled/Active Indicator

These user definable indicators light when turned on through the RS-422 serial interface port.

Alarm Indicator

The Receiver lights this indicator to indicate it has detected an internal condition that requires attention.

Refer to Table 4-2 in Chapter 4, “Command Listing and Status Information” of this guide for information on Alarm capability.

GPS Lock Indicator

This indicator lights when the Receiver is tracking satellites and phase-locked its internal reference to the reference time derived from satellite data. This indicator will go off whenever the above condition is not met, which would typically occur when satellite tracking is lost or while the Receiver is powering up.

The principal Receiver setting that can affect this indication is manual selection of reference oscillator holdover operation.

Holdover Indicator

The Receiver lights this indicator to show that GPS lock has been lost and the Receiver is in holdover mode. It only lights it the Receiver has been locked once; it will never light until the Receiver has been locked once. While in holdover, the internal reference oscillator will be adjusted by SmartClock™ technology .

NOTE If the Holdover indicator lights before the Receiver has been locked

24 hours, then the Receiver has not had sufficient time to learn the characteristics of the internal reference oscillator. In this case, the specification for Timing Accuracy during holdover may not be met. This specification applies only after the Receiver has had sufficient stable operation time.

Refer to the subsection titled “Holdover Description” on page 2-11 in this chapter for more information.

User Guide 2-9

Chapter 2 Features and Functions

Connecting to a Computer

To connect the GPS Receiver to a computer, you must have an appropriately wired RS-422 interface cable (customer supplied). Refer to Table 2-3 for rear-panel I/O Port 1 J3 pin assignments and signal characteristic information.

The interface cable must also have the proper connector on each end and the internal wiring must be correct. The GPS Receiver is considered the Data Terminal Equipment (DTE) for this interface.

The Z3801A rear-panel serial interface port has a fixed configuration as described in Chapter 1 of this guide on page 1-3.

2-10 User Guide

Chapter 2 Features and Functions

Operating Concepts

General

The time required to acquire GPS lock as described in the following paragraph can vary significantly depending on your local conditions. In general, we strongly recommends that your antenna and cables be set up in accordance with the information provided in this guide prior to using the output signals of the Receiver to ensure they are valid.

Acquiring lock does not mean that the Receiver is fully operational and meeting all specifications. It just means that the Receiver has detected enough satellites to start its survey mode to determine its precise location. An internal measurement FFOM (Frequency Figure of Merit) becomes 0 when the internal loops reach their proper time constants, indicating that the output frequency and 1 PPS signals are now fully operational and meeting their specifications. Under the worst conditions, the Receiver may take up to 24 hours to achieve FFOM = 0. FFOM can be monitored in the Reference Outputs quadrant of the Receiver Status screen (see Figure 3-1 in Chapter 3, “Using the Receiver Status Screen,” of this guide). Also, using the appropriate SCPI query command will provide FFOM value (refer to Chapter 4, “Command Listing and Status Information,” in this guide for specifics).

The Receiver is designed to automatically detect and acquire satellites in order to begin providing precise frequency and time information. Until such acquisition is complete and the instrument is locked with FFOM = 0, the signals produced on the rear panel are not precise.

Holdover Description

If the GPS signal is interrupted, the Receiver enters an intelligent holdover mode that uses SmartClock® technology. SmartClock takes over control of the quartz oscillator that has been steered to the GPS reference during locked operation. SmartClock predicts the performance of the quartz oscillator based on the information gathered during the “learning period” (locked to GPS). Corrections are automatically issued over time, keeping the performance of the quartz oscillator as close as possible to the performance achieved while locked to the GPS reference signal.

Holdover frequency is maintained to better than <1 × 10 The time specifications 1 µs locked, and 7µs unlocked for 24 hours. When the GPS reference signal is restored, the Receiver automatically switches back to normal mode of operation.

-9

per day.

User Guide 2-11

Chapter 2 Features and Functions

In Case of a Problem

Hours after powerup, Receiver not establishing GPS lock

SYMPTOM

Solution Check antenna:

Date, time, and position still show power-up defaults, or these parameters are incorrect.

Receiver Position Mode = Survey.

Receiver cycling from one set of satellites to another.

No satellites consistently tracked.

• Verify antenna has an unobstructed view of the sky—antenna is not under or beside an impervious object.

• Verify antenna is connected.

• Verify antenna is connected properly:

– cable run not too long.

– cable with antenna attached neither shorted nor open.

• Verify antenna is being properly driven—Hint:

(1) connect Tee-connector to Receiver’s rear-panel ANTENNA J1

input; connect antenna cable to one end of Tee. Measure a little less than +5 Volts from the other end of the Tee using a digital voltmeter (DVM) as shown in Figure 2-1. If your reading is a lot less than +5 Volts, you will have to determine if the line amplifier or lightning arrester is at fault by using conventional troubleshooting isolation techniques. If the line amplifier and lightning arrester are good, then the antenna may be faulty.

(2) If the Receiver +5 Volts is okay, check +5 Volts at the antenna

end of the cable with a voltmeter connected between the center conductor and shell. If insufficient voltage is present, it may indicate that the shield of the cable is not making adequate contact to one of the cable connectors.

• After the antenna connection has been verified, cycle power on the Receiver to facilitate rapid recovery from the fault.

NOTE Remove the Tee connector and restore antenna connection as loading of

the Tee connector will prevent proper reception of the GPS signal by the antenna.

2-12 User Guide

Chapter 2 Features and Functions

In Case of a Problem

SYMPTOM

SOLUTION

SYMPTOM

SOLUTION

1 Tee-connector 2 DVM

Figure 2-1. Measuring +5 Volts Across Antenna Input

Same as previous symptoms, except Receiver Position Mode = Hold.

Enable SURVEY mode using specified command.

Receiver not maintaining GPS lock

Position data incorrect.

Survey to obtain correct position,

SYMPTOM

SOLUTION

Correct position data using specified command.

Position data correct.

Sufficient satellites in view.

No satellites tracked.

If candidate satellites are marked “Ignore” on status screen, disable the feature which ignores satellites.

If candidate satellites are below the mask angle specified on Receiver Status screen, reset the elevation mask angle. Default is 10 degrees— all satellites between the horizon and 10 degrees of the horizon are masked.

User Guide 2-13

Chapter 2 Features and Functions

In Case of a Problem

2-14 User Guide

Using the Receiver Status Screen

Chapter 3 Using the Receiver Status Screen

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 Receiver Status Screen page 3-3

– Tutorial on Using the Status Screen to Interface

With the Receiver

– Demonstration of Holdover Operation page 3-8

• Receiver Status Screen Data page 3-11

– SYNCHRONIZATION Section of the Status

Screen

– 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 page 3-20

page 3-4

page 3-12

3-2 User Guide

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

The Receiver Status screen can be accessed when the GPS Receiver is connected to a properly configured terminal or PC. There are two ways to access and use the Receiver Status screen:

• By installing a commercially available terminal emulation program, connecting the GPS receiver to a DCE device (Digital Communications Equipment) via the rear-panel I/O Port 1 J3 RS-422 port using an appropriate (customer supplied) system interface cable, and manually sending the :SYSTEM:STATUS? query. (Refer to Chapter 1, “Getting Started,” in this guide.)

• By installing and operating the SatStat program which automatically generates continual status screen updates, and connecting the GPS Receiver to a PC via via the rear-panel I/O Port 1 J3 RS-422 port using an appropriate (customer supplied) system interface cable. (Refer to the sections titled “Installing the Automated HP SatStat Program for Continual Status Updates” and “Operating the Automated HP SatStat Program” in Chapter 1, “Getting Started,” of this guide for details on installation.)

The following tutorial demonstrates how you can use the Receiver Status screen to observe GPS Receiver operation. The tutorial uses the manual (:SYSTEM:STATUS?) method.

User Guide 3-3

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

Tutorial on Using the Status Screen to Interface With the Receiver

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

An initial power-up screen is displayed, which is similar to the demonstration screen shown in Figure 3-1. The first data that you should look at is in the SYNCHRONIZATION area of the screen. It is telling you that it is in the Power-up state as indicated by the >> marker. That is, the Receiver has just been put on line.

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

Locked Recovery Holdover

Power-up:GPS acquisition

ACQUISITION Satellite Status

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

[ 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

12:00:00[?] 01 JAN 1996

0 ns

Survey: 0% complete Suspended:Track <4 sats

NW0:00:00.000

Outputs Invalid

FFOM

[GPS 1PPS Invalid]

0:00:00.000

0 m (MSL)

[ 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.

3-4 User Guide

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

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 an 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.

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 Satellite Status

Tracking: 5

PRN El Az

337

188

113

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 134 117

54 29

128

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

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 (MSL)

[ OK ]

Figure 3-2. Receiver Status Screen Displaying Initial Satellite Acquisition

]

User Guide 3-5

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

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 from the Not 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 signal strength (SS). A good signal strength is a number above 20, which would be efficient for the Receiver to operate. Numbers below 20, 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 position. 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.

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.

3-6 User Guide

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

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

SYNCHRONIZATION SmartClock Mode

Locked to GPS: stabilizing frequency

Recovery Holdover Power-up

ACQUISITION Satellite Status

Tracking: 6

PRN El Az

301

186

102

317

31 5216 41 ELEV MASK HEALTH MONITOR Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

10 deg

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

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

Not Tracking: 1

PRN 82 71 61 84 54

16 13 258

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

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 (MSL)

[ 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.

Also indicated is a prediction of the accuracy of the Receiver should it go into holdover operation.

User Guide 3-7

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

Demonstration of Holdover Operation

CAUTION The Receiver typically reaches stable state 24 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 :

• The front-panel Holdover LED will illuminate, and

• after sending the :SYSTEM:STATUS? query again, a screen similar to Figure 3-4 should appear.

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

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Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

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

Locked to GPS Recovery Holdover: GPS 1PPS invalid

Power-up

ACQUISITION Satellite Status

Tracking: 0

ELEV MASK HEALTH MONITOR

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

10 deg

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

Holdover Duration: 0m 14s

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

Not Tracking: 7

El Az

PRN *2 71 316 *7 41 186

15 11 86 *19 35 107 *22 68 78 *26 23 314 *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 Present 1.0 us

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 (MSL)

[ 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, instantaneously, 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 (24 hours), the Receiver status screen would show that the Receiver went into holdover, and the Receiver’s outputs were maintained during holdover by the SmartClock.

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 to Figure 3-5.

User Guide 3-9

Chapter 3 Using the Receiver Status Screen

Using and Reading the Receiver Status Screen

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

SYNCHRONIZATION SmartClock Mode

Locked to GPS: Stabilizing frequency

Recovery Holdover Power-up

ACQUISITION Satellite Status

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

80 312

10 deg

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

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

Not Tracking: 0

SSEl

80 73 64 87 55 49

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

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 (MSL)

[ 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.

3-10 User Guide

Chapter 3 Using the Receiver Status Screen

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

PRN

El Az 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

10 deg

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

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

SS 168 125 132 168 246 133

Not Tracking: 1

PRN El Az

14 11 82

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

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 (MSL)

[ 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.

User Guide 3-11

Chapter 3 Using the Receiver Status Screen

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

Outputs Valid while the unit is in steady-state operation.

while the unit is in holdover or is locked but has not achieved steady-state operation, or

SmartClock Mode

The SmartClock Mode area of the screen shows the four operating modes:

•Locked to GPS

• Recovery

•Holdover

• Power-up

As shown in the sample status screen in Figure 3-6, a >> symbol indicates the current operating mode.

Locked to GPS indicates that the Receiver is locked to GPS. The front-panel GPS Lock LED will be illuminated.

When stabilizing frequency ... is shown, the time output (1 PPS) signal is locked and can be used, but the frequency outputs (10 MHz) are not at their final or most stable state.

Recovery indicates that the Receiver is actively working to become locked to GPS. All conditions needed to proceed towards a lock have been met. Expect an eventual spontaneous transition to a lock (unless changing external conditions prevent this, such as loss of tracked satellites.)

Holdover indicates that the Receiver is waiting for conditions that are needed to allow the process of recovery from holdover to begin. Once these conditions are met, the Receiver will transition on its own to the recovery mode.

When the GPS 1PPS CLK invalid message follows the Holdover label, the internal GPS 1 PPS reference signal is inaccurate.

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Chapter 3 Using the Receiver Status Screen

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 1 PPS output. A low TFOM value indicates a more accurate output. 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.

TFOM Value Time Error

(in nanoseconds)

*0 less than 1 5 10

*1 1–10 6 105–10

*2 10–100 7 106–10

3 100–1000 8 107–10

410

–10

TFOM Value Time Error

(in nanoseconds)

–10

9 greater than 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.

User Guide 3-13

Chapter 3 Using the Receiver Status Screen

Receiver Status Screen Data

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

Receiver’s 10 MHz output. The 10 MHz output is controlled by the SmartClock’s Phase-Locked Loop (PLL). Thus, the FFOM value is determined by monitoring the status of the PLL.

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—10 MHz output within specification.

1 PLL stabilizing

2 PLL unlocked (holdover)—Initially the 10 MHz output

will be within specifications. However, when in holdover, the 10 MHz output will eventually drift out of specification.

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.

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Chapter 3 Using the Receiver Status Screen

Receiver Status Screen Data

Tracking, Not Tracking

The Tracking table indicates the number of satellites the unit 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.

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 to 90°. The predicted elevation is derived from the 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).

SS 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

Not OK

Acq

Acq .

Acq . .

ELEV MASK indicates the elevation mask angle in degrees. Satellites at or

indicates that the user has chosen to exclude this satellite from a list of satellites available for tracking.

indicates GPS has reported that this satellite is unhealthy.

indicates the unit is attempting to acquire the satellite signal.

indicates the unit is reading timing information from the satellite.

indicates the unit is reading satellite orbital information.

above this elevation angle are considered for tracking.

*attempting

indicates that the unit is attempting to track a satellite.

to track

User Guide 3-15

Chapter 3 Using the Receiver Status Screen

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 UTC

Assessing stability ...

Inaccurate, not tracking

Inaccurate, inacc position

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.

Absent or freq incorrect

ANT DLY (antenna delay) displays the user-entered value that is used to compensate for the propagation delay of the antenna cable.

3-16 User Guide

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

Chapter 3 Using the Receiver Status Screen

Receiver Status Screen Data

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 mean sea level (MSL).

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

AVG LAT indicates the average latitude (North or South) position of the unit in degrees, minutes, and seconds.

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

AVG HGT indicates average height of the unit’s antenna, in meters above mean sea level (MSL).

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

User Guide 3-17

Chapter 3 Using the Receiver Status Screen

Receiver Status Screen 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.

3-18 User Guide

Chapter 3 Using the Receiver Status Screen

Receiver Status Screen Data

User Guide 3-19

Chapter 3 Using the Receiver Status Screen

t v k

The Receiver Status Screen at a Glance

SYNCHRONIZATION

time and frequency reference signals with GPS.

HP SmartClock technology compares and adjusts (locks) the reference oscillator to GPS. In the absence of GPS, HP SmartClock operates in "holdover" mode, which maintains precise time and frequency over an extended duration by predicting and compensating for aging and temperature effects.

SmartClock Mode

Locked to GPS

Reference signals are synchronous with GPS. When

is reported, short-term frequency errors limit the

frequency

accuracy of the 10-MHz reference.

Recovery: ...

Adjusting the frequency and phase of the oscillator to correct errors accrued while in holdover operation. The phase difference between the GPS 1PPS reference and disciplined oscillator 1PPS signal is shown.

Holdover: ...

Reference outputs are not synchronous with GPS due to the reported condition. HP SmartClock maintains timing accuracy by applying learned oscillator characteristics.

GPS 1PPS invalid

Not tracking any satellites, or position is inaccurate

1PPS TI exceeds hold threshold

Phase difference between 1PPS signals exceeds a specified limit (HOLD THR)

manually initiated

User-initiated holdover. Holdover Duration is the cumulative duration of holdover and

recovery operations.

Power-up: ...

Warm-up/initial adjustment of the oscillator.

Reference Outputs

Measures of signal quality: TFOM (Time Figure of Merit)

Accuracy of the 1PPS reference. A number between 0 (best) and 9 that denotes a timing error of 10 nanoseconds.

FFOM (Frequency Figure of Merit) Frequency stability of the 10-MHz reference:

0 Stable, signal within specification 1 Stabilizing this signal 2 Holdover mode; frequency will drift 3 Signal is unusable.

1PPS TI (Time Interval) Average phase difference between the GPS reference and oscillator 1PPS signals.

HOLD THR (Holdover Threshold) 1PPS phase difference that while exceeded forces holdover operation.

profiles the process of synchronizing

stabilizing

TFOM-1

to 10

TFOM

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

Locked Recovery:

Holdover Power-up

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

phase alignment [TI +1.296 us]

Holdover Duration: 1m 45s

ACQUISITION Tracking: 1 PRN El AzSSEl

31 16875 254

ELEV MASK

HEALTH MONITOR Self Test: OK Int Pwr: OK Oven Pwr: O

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

10 deg

Not Tracking: 9 PRN

* 2 19 313 * 4 Acq * 5 * 7 -- --* 9

15 *24 *26 *attempting to track

Acq

35 140 Ignore

Acq

47 258

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

HEALTH MONITOR

components and internal signals.

Self Test Result of the last diagnostic check of the processor

Int Pwr Oven Pwr OCXO EFC GPS Rcv

Holdover Uncertainty

Estimations of timing accuracy while in holdover mode, which reflect the extent to which HP SmartClock has learned the oscillator's characteristics:

Predict

Maximum timing error that can be expected over the initial 24 hours of holdover operation.

Present

Maximum timing error currently expected.

reports the operational status of key receiver

system, reference oscillator, satellite receiver and power supplies

Internal power supplies Oscillator oven power supply Oscillator 1PPS output Oscillator frequency control voltage Satellite receiver communication interface.

Receiver S

PRN El Az

Not OK

Tra

Sat mus deri trac sele elev

Not

Sat be v pre

Tra abo

Acq

Ign Not

3-20 User Guide

Chapter 3 Using the Receiver Status Screen

The Receiver Status Screen at a Glance

eiver Status

.........

1.296 us]

n: 1m 45s

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

NElAz 9

Not OK

track

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

n Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK

Tracking

Satellites currently tracked by the receiver. Four or more satellites must be tracked to determine position. Timing information is derived from all tracked satellites, and is considered accurate while tracking at least one satellite from a known position. The receiver selects satellites highest in the sky that are at or above the minimum elevation angle specified by ELEV MASK.

Not Tracking

Satellites considered for tracking. These satellites are predicted to be visible or are selected by the "sky search" algorithm. Visibility is predicted from the satellite almanac, current time and position.

Tracking and Not Tracking tables provide supplemental information about satellite position, signal strength and health:

PRN Identification number (pseudorandom noise code)

EI Elevation of the satellite (degrees) predicted by the

Az Azimuth of the satellite (degrees), referenced to true

SS Relative signal strength, proportional to the signal-to-

Acq Locking code and carrier tracking loops to initially

Acq . Demodulating the satellite broadcast (NAV) message,

Acq .. Reading the satellite ephemeris (orbital information)

Ignore The satellite is excluded from the selection process. Not OK GPS or Time RAIM reports the satellite is unhealthy.

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

Outputs Valid/Reduced Accuracy

[

Reference Outputs TFOM FFOM 1PPS TI -HOLD THR Holdover Uncertainty Predict 55.8 us/initial 24 hrs Present 1.0 us

Time UTC GPS 1PPS Synchronized to UTC ANT DLY

Position MODE

AVG LAT AVG LON AVG HGT

1.000 us

[ GPS 1PPS Valid ]

03:11:57 31 Jan 1996

120 ns

Survey: 26.1% complete Suspended: track <4 sats

NW37:19:31.797

121:59:52.018

60.52 m (MSL)

[ OK ]

assigned to the satellite. Satellites are sorted by ascending PRNs.

almanac. "---" denotes it is unknown, such as when the satellite is not predicted to be visible but is selected for tracking by the sky search algorithm.

north, predicted by the almanac; "---" if unknown.

noise ratio of the received signal. The maximum value is 255; 20 to 30 is the minimum range for stable tracking.

acquire the satellite signal.

and determining current time.

from the NAV message.

]

ACQUISITION

GPS. GPS provides time-of-day information and a 1PPS reference signal used to discipline the internal oscillator.

Time

Time of day:

UTC LOCAL GPS LOCL GPS

[ ? ] identifies a default power-up setting that is corrected when the first satellite is tracked.

+1 (or -1) leap second pending correction to UTC is pending.

GPS 1PPS indicates the validity of the GPS 1PPS reference: Synchronized to UTC (or GPS Time)

1PPS reference is synchronous with GPS

Questionable accuracy... Assessing stability...

1PPS must be accurate for 35 seconds

Inaccurate: not tracking

One or more satellites must be tracked

Inaccurate: inacc position

Postition must be known to derive time

Inaccurate: Time RAIM err

GPS timing integrity is suspect.

ANT DLY offsets the GPS 1PPS reference to compensate for signal propagation delays introduced by the antenna system. (Time is referenced to the position of the antenna.)

Position

An accurate position is necessary to transfer time from GPS. Two position MODEs are provided, hold and survey.

In Hold mode, a fixed position is used to derive time. This position may be specified if known, or determined by the survey process.

In Survey mode, position is determined from GPS. Four or more satellites must be tracked. Successive positional estimates (pseudoranges) are refined to obtain the true position, which is entered as the held position at the completion of this process.

Averaged (AVG) position coordinates and progress are reported while surveying. When surveying is suspended, an advisory message describes the reason:

Suspended: track <4 sats Four or more satellites must be tracked to determine position

Suspended: poor geometry DOP (dilution of precision) is too large for an accurate pseudo range measurement.

Specifying an approximate initial (INIT) position will reduce satellite acquisition time.

profiles the process of acquiring precise time from

Coordinated Universal Time UTC with local time zone offset GPS Time GPS Time, with time zone offset.

is reported if a leap second

User Guide 3-21

Chapter 3 Using the Receiver Status Screen

The Receiver Status Screen at a Glance

3-22 User Guide

Command Listing and Status Information

Chapter 4 Command Listing and Status Information

Chapter Contents

This chapter provides a description of each command that can be used to operate the Z3801A GPS Receiver.

This chapter is organized as follows:

• Z3801A Commands page 4-3

– SCPI Conformance Information page 4-3

– SCPI Syntax Conventions page 4-3

– Description of Commands page 4-3

– Detailed Description of the Two Time Code

Formats

• Status Information page 4-14

– Standard Event Register Bit Assignments page 4-14

– Questionable Status Register Bit Assignments page 4-15

– Operation Status Register Bit Assignments page 4-15

– Powerup Status Register Bit Assignments page 4-16

– Holdover Status Register Bit Assignments page 4-16

– Hardware Status Register Bit Assignments page 4-17

• Information that Appears in the Diagnostic Log page 4-18

• Model for Powerup, Locked, and Holdover States page 4-19

• Error Messages page 4-21

page 4-12

4-2 User’s Guide

Chapter 4 Command Listing and Status Information

Z3801A Commands

SCPI Conformance Information

The Standard Commands for Programmable Instruments (SCPI) commands used in the Z3801A are in conformance with the SCPI Standard Version 1994.0.

SCPI Syntax Conventions

[ ] An element inside brackets is optional. Note, the brackets

are NOT part of the command and should NOT be sent to the Receiver.

1 | 2 Means use either 1 or 2.

<numeric_value> Means enter a number.

SENSe Means you MUST use either all the upper case letters or

the entire word. The lower case letters are optional. For example, SENS and SENSE are both valid. However, SEN is not valid. (Note, SENSe is used here as an example, but this convention is true for all SCPI commands.) 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.

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

send the quotation marks with the command.

Description of Commands

Two command tables are provided:

• Table 4-1, which lists the “INSTALL” language commands (used to download firmware).

• Table 4-2, which lists the “PRIMARY” language commands (used for normal instrument operation).

User’s Guide 4-3

Chapter 4 Command Listing and Status Information

Z3801A Commands

Refer to the 58503B/59551A GPS Receivers Operating and Programming Guide (58503-90013) for detailed descriptions of

commands listed in tables 4-1 and 4-2.

Table 4-1. Z3801A INSTALL Commands

Keyword/Syntax Parameters/

Responses

*CLS Clear errors.

*IDN? returns unquoted string Identify revision of download control firmware.

DIAGnostic

:DOWNload <Motorola® S_Record> Send down a Motorola S-Record.

:ERASe Erase Flash.

:SYSTem Node Only.

:ERRor? returns INT, quoted string first parameter is error number, quoted string is error

:LANGuage “PRIMARY” | “INSTALL” Use “PRIMARY” to switch to normal operation

Comments

Node Only. “INSTALL” language is used for downloading firmware.

description.

commands.

Table 4-2. Z3801A PRIMARY Commands

Keyword/Syntax Parameters/

Responses

Comments

*CLS Clears event status registers and error queue.

*ESE <mask value> Sets or returns standard event status enable

*ESR? returns register value Returns and clears standard event status

*IDN? returns unquoted string Returns identification string.

*SRE <mask value> Sets or returns service request enable register.

*STB? returns INTEGER Returns the value of the Status Byte.

*TST? returns INTEGER Runs self tests. 0 = passed, non-zero is test

specific code.

4-4 User’s Guide

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

:DIAGnostic

:IDENtification Node Only.

:GPSystem? returns a sequence of

quoted strings

:LIFetime Node Only.

:COUNt? returns 32-bit integer Returns lifetime count, indicating total powered

:LOG Node Only. See list of log messages later in this

:CLEar [<log count>] Clears the log. The optional log count parameter

:COUNt? returns INTEGER Identifies number of entries in log.

[:READ]? [<numeric>]

send: [<numeric>] returns: quoted string

Comments

Node Only

Returns the model number, serial number, and revision of the internal GPS receiver.

on time.

document.

is provided to ensure that no log entries are unread at the time of the clear. If value sent in doesn't match current log entry count (Use :DIAG:LOG:COUNt? to obtain this number.), the clear will not take place.

Outputs single log entry. Optional numeric parameter can be used to identify a specific log entry. If no numeric is provided, will output most recent log entry.

:ROSCillator Node Only.

:EFControl Node Only.

[:RELative]? returns INTEGER in % Outputs EFC value in %, range -100% to +100%.

Note :DIAG:ROSC:EFC? will give same response.

:QUERY Node Only

:RESPonse? returns unquoted string Queries the last response item. Used when

transmission error has occurred.

:LED

:ACTive 0 | OFF | 1 | ON Sets or queries Active LED.

:ALARm? returns 0 | 1 Query Alarm LED. Conditions for enabling alarm

:USER 0 | OFF | 1 | ON Provides a way to directly set Alarm.

:ENABled 0 | OFF | 1 | ON Sets or queries Enabled LED.

:GPSLock? returns 0 | 1 Queries Lock LED.

:HOLDover? returns 0 | 1 Queries Holdover LED.

Node Only

are determined via :LED:ALARm:USER.

User’s Guide 4-5

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

[SOURce]:PTIMe

:FFOMerit? returns INT Frequency figure of merit. Generates an error

:GPSystem Node Only

:ADELay <numeric in seconds> Sets antenna delay in seconds. Caution: use of

:EMANgle <numeric in deg> Sets elevation mask angle in degrees. 90 is

:INITial Node Only. By setting all of the commands in this

Comments

Node Only

(−230, Data corrupt or stale) when this value is unavailable.

this command while Receiver is in normal locked operation can cause jump to holdover.

straight up.

group, faster initial GPS acquisition may occur. Receiver uses initial date, time, position with almanac to predict which satellite should be visible. Note that time and position only have to be approximate for this to speed up acquisition. Acquisition will still occur even if these commands are not used.

:DATE <yr>,<mo>,<day> Use to speed up tracking of first satellite.

Not queryable.

:TIME <hr>,<min>,<sec> Use to speed up tracking of first satellite.

Not queryable.

:POSition <location> Use to speed up tracking of first satellite.

<location> = N | S, <deg>, <min>, <sec>,E|W,<deg>,<min>,<sec>,<elevation in m (mean sea level). Not queryable.

:POSition send: <location> |

SURVey | LAST

returns: <location>

:HOLD Node Only

:LAST? returns location

(see definition with :GPS:INIT:POSition)

Places Receiver in position-hold mode at this location. See above for <location> definition. SURV means to use current survey location estimate, LAST means use last position-hold value. During survey, query returns current survey location estimate.

Identifies last hold position. This can be used if the Receiver has been commanded to survey but is making no progress. This query returns the last location.

4-6 User’s Guide

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

[SOURce]:PTIMe (Cont.)

:GPSystem (Cont.)

:POSition (Cont.)

:SURVey (Cont.) Node Only

:PROGress? returns INT in % During survey, provides % completed (from

[:STATe] send: ONCE

returns: ONCE | 0

:SATellite Node Only.

:TRACking? returns INT, INT, ... Returns a list of all satellites being tracked.

:TRACKing Node Only.

:COUNt? returns INTEGER Returns the number of satellites being tracked.

Comments

survey start until automatic transition to position hold).

Specify ONCE to survey position. When position hold mode is attained, 0 is returned when queried.

Satellites are identified by PRN (range 1...32). 0 means no satellites being tracked.

:IGNore INT, INT, ...

(one or more PRNs)

:COUNt? returns INTEGER Returns the number of satellites excluded from

:INCLude INT, INT, ...

(one or more PRNs)

:COUNt? returns INTEGER Returns the number of satellites considered for

:VISible Node Only.

:PREDicted Node Only.

:COUNt? returns INTEGER Returns the number of satellites that the almanac

:PREDicted? returns INT, INT, ... Returns list of satellites (PRN) that the almanac

Sends or queries list of satellites (use PRN) to ignore. 0 means no satellites being ignored.

tracking.

Sends or queries for list of satellites (use PRN) to include. 0 means no satellites being included (i.e., they are all on ignore list).

tracking.

predicts are visible.

predicts should be visible, given date, time, and location (If any of these values are incorrect, the prediction will be incorrect). 0 means no satellites are predicted to be visible.

User’s Guide 4-7

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

[SOURce]:PTIMe (Cont.)

:LEAPsecond

:ACCumulated? returns INT Identifies accumulated time difference (in

:GPSTime? returns INT in HEX GPS time of next pending leapsecond.

:SYNChronization Node Only.

:IMMediate Used during recovery to initiate a near

:TCODe:FORMat F1 | F2 Selects or queries the format of the time code

:TCODe? returns quoted string Provides timecode message 980 to 20 ms prior to

Comments

seconds) between GPS and UTC time scales.

instantaneous alignment of GPS 1 PPS and Receiver output 1 PPS.

message returned by :PTIM:TCOD?

1 PPS of indicated time. Format is specified by :PTIM:TCOD:FORMat. Type of data provided: time in secs of next on-time edge, TFOM, leapsec data, alarm indication, and service request.

See “Detailed Description of the Two Time Code Formats” on page 4-12 for complete information.

:TINTerval? returns REAL in seconds Returns the filtered GPS 1 PPS to internal

oscillator 1 PPS interval. Generates an error (−230, Data corrupt or stale) when this interval is unavailable (e.g., if no GPS 1 PPS or no satellites available).

[SOURce]:ROSCillator

:HOLDover Node Only

:DURation? returns REAL in seconds,

0 | 1

:INITiate Places the Receiver in holdover. It will stay there

:RECovery Node Only

:INITiate Initiates a recovery from holdover. Use this

Node Only. (Note: [SOURCe]:SYNChronization

is an alias for [SOURCe]:ROSCillator.)

First parameter is amount of time that Receiver has been in current holdover or amount of time of last holdover, depending on holdover state. Second parameter identifies holdover state: 0 = not in holdover, 1 = in holdover.

until you send :ROSC:HOLD:REC:INITiate.

command to take the Receiver out of a manually selected holdover. It is not used to initiate holdover recovery in any other situation.

4-8 User’s Guide

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

[SOURce]:ROSCillator (Cont.)

:HOLDover (Cont.)

:RECovery (Cont.)

:LIMit Node Only.

:IGNore Action only. Causes transition in holdover state

:DURation Node Only.

:THReshold send: <numeric> [s]

returns: INTEGER

:EXCeeded? returns 0 | 1 Returns 1 when the duration of holdover

Comments

from waiting-to-recover to recovering when the reason this transition isn't taking place is due to the TI limit being exceeded.

Sets the duration (in seconds) that should be used as a limit each time holdover begins. When the receiver remains in holdover longer than this duration, the EXCeed state will change (see next command).

operation exceeds the threshold set by :ROSC:HOLD:DUR:THReshold.

:LIMit Node Only.

:THReshold <numeric in seconds> Sets the time interval limit (in seconds) which, if

exceeded for some duration, will cause a transition from locked to holdover.

:TUNCertainty Node Only.

:PREDicted? returns REAL in seconds Returns an estimate of the time error that can be

expected for a 1 day holdover, given the current state of SmartClock learning in the Receiver.

:PRESent? returns REAL in seconds Returns the present timing uncertainty while in

holdover operation.

:WAITing? returns HARDware | GPS |

LIMit | NONE

[:STATe]? OTH, or HOLD, or WAIT,

or REC, or LOCK, or POW.

Returns prioritized reason why Receiver is waiting to recover: HARD means there is an internal hardware reason, GPS means there are no satellites, LIM means the TI between GPS and internal oscillator is exceeding the limit. NONE means it isn't waiting to recover.

OTH indicates in diagnostic mode or temporary start-up mode; HOLD indicates in manual holdover mode; WAIT indicates waiting for external conditions to allow recovery from holdover; LOCK indicates locked to GPS; POW indicates in power-up prior to first lock.

User’s Guide 4-9

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

:STATus

:OPERation Node Only.

:CONDition? returns register value

:ENABle <mask value>

[:EVENt]? returns register value

:HARDware Node Only. (See table in “Status Information”

:CONDition? returns register value

:ENABle <mask value>

[:EVENt]? returns register value

:NTRansition <filter value>

:PTRansition <filter value>

:HOLDover Node Only. (See table in “Status Information”

:CONDition? returns register value

:ENABle <mask value>

Comments

Node Only.

starting on page 4-14 for bit assignments.)

[:EVENt]? returns register value

:NTRansition <filter value>

:PTRansition <filter value>

:NTRansition <filter value>

:POWerup Node Only. (See table in “Status Information”

starting on page 4-14 for bit assignments.)

:CONDition? returns register value

:ENABle <mask value>

[:EVENt]? returns register value

:NTRansition <filter value> ____

:PTRansition <filter value> ____

4-10 User’s Guide

Chapter 4 Command Listing and Status Information

Z3801A Commands

Table 4-2. Z3801A PRIMARY Commands (continued)

Keyword/Syntax Parameters/

Responses

:STATus (Cont.)

:PRESet

:ALARm Presets the status/alarm reporting system to

:QUEStionable Node Only. (See table in “Status Information”

:CONDition? returns register value ____

:USER CLEar | SET User-controlled condition for questionable

:ENABle <mask value> ____

[:EVENt]? returns register value ____

:NTRansition <filter value> ____

:PTRansition <filter value> ____

Comments

Node Only

generate an alarm when one or more factory-default operating conditions occurs. These conditions are also retored by :SYST:PRESet.

starting on page 4-14 for bit assignments.)

:SYSTem

:ERRor? returns INT, quoted string The first parameter is error number, quoted string

:LANGuage “PRIMARY” | “INSTALL” Select “INSTALL” for firmware download.

:PRESet Returns Receiver parameters to factory settings.

:STATus? returns ASCII Outputs a fully formatted status screen.

Node Only

is error description.

User’s Guide 4-11

Chapter 4 Command Listing and Status Information

Z3801A Commands

Detailed Description of the Two Time Code Formats

The :PTIMe:TCODe? time code query returns an ASCII string that begins with “T1” or “T2” followed by the time of the next 1 PPS pulse, measures of the accuracy and stability of reference signals, and service-request status.

The syntax and content of these messages are (Note that spaces are

inserted here for clarity; there are no embedded spaces in the actual message.):

T1 #Hxxxxxxxx t f l r v cc <cr><lf> (19 characters,

excluding <cr><lf>)

T2 yyyymmddhhmmss t f l r v cc <cr><lf> (23 characters,

excluding <cr><lf>)

where (see next page for description of each item in the format):

4-12 User’s Guide

Chapter 4 Command Listing and Status Information

Z3801A Commands

T1 or T2 is a literal, two-character header that identifies the format of

the message.

[T1 format]

xxxxxxxx is the date and time of the next 1 PPS pulse, referenced to

[T2 format]

yyyymmdd

hhmmss is the time of the next 1 PPS pulse, referenced to UTC or local

is a literal, two-character prefix of the unsigned hexadecimal number that follows.

GPS Time, expressed as the number of seconds that have elapsed since January 6, 1980.

is the date of the next 1 PPS pulse, referenced to UTC or local time, expressed in year (yyyy)/month (mm)/day (dd) format.

time, expressed in hour (hh)/minute (mm)/second (ss) format.

t is the Time Figure of Merit, a measure of the accuracy of the

1 PPS pulse.

f is the Frequency Figure of Merit, a measure of the stability of

the 10 MHz signal.

l is the status of a pending leap second adjustment:

0 (no adjustment pending), or + (a positive adjustment is pending), or

− (a negative adjustment is pending).

r is the request-for-service summary bit of the Status Byte

v is the validity of time-related information in this message:

0 (valid) or 1 (invalid).

cc is the checksum of all preceding characters, computed as the

sum of their ASCII-encoded values, and reported as a two-digit, ASCII-encoded hexadecimal number.

Use the :PTIMe:TCODe:FORMat <format> command to change the format of this message:

:PTIMe:TCODe:FORMat F1 — to select “T1”

:PTIMe:TCODe:FORMat F2 — to select “T2”

:PTIMe:TCODe:FORMat? queries the current setting. It returns an ASCII string, either “F1” or “F2”.

T1 is the default time code format.

User’s Guide 4-13

Chapter 4 Command Listing and Status Information

Status Information

Listed below are the specific bit assignments for the status registers that have assignments that are customized by the timing Receiver. See Figure 4-1 for a simplified illustration of the relationships between the Status Registers.

Powerup

Operation

Holdover

Hardware

Questionable

Standard Event

Figure 4-1. Simplified Relationships Between Status Registers

Standard Event Register Bit Assignments

Bit Information Reported Comments

0 Not Used ____

Status Byte Registers &

Service Request Enable

1 Not Used ____

2 Not Used ____

3 Device-dependent Error These are errors in the -3xx range or any positive numbered errors.

4 Execution Error These are errors in the -2xx range.

5 Command Error These are errors in the -1xx range.

6 Not Used ____

7 Power-On Identifies that the unit has undergone a transition to power-on

(useful for detecting if power has been lost).

4-14 User’s Guide

Chapter 4 Command Listing and Status Information

Status Information

Questionable Status Register Bit Assignments

= Positive Transition

= Negative Transition

= Enable

= Alarm LED

Bit Information Reported Comments P N E A

0 Time has been set. Event only This could occur after an extensive holdover

period. When GPS is re-acquired, if receiver time differs from GPS time, this bit will be set.

1 User-reported ____ 0000

__11

Operation Status Register Bit Assignments

= Positive Transition

= Negative Transition

= Enable

= Alarm LED

Bit Information Reported Comments P N E A

0 Powerup operation summary Summary of powerup status register 1000

1 Locked operation Condition = 1 if locked to GPS, 0 otherwise. 1000

2 Holdover operation summary Summary of holdover status register. 1011

3 Position hold operation Condition = 1 if in position-hold mode, 0 if in

survey mode.

4 Sufficient satellites to allow

lock to GPS

5 Hardware status summary Summary of hardware status register. 1011

6 Log almost full Condition = 1 indicates that the diagnostic log

Condition = 1 indicates current satellite tracking allows for locking.

is nearly full (you may want to read and clear it)

1000

User’s Guide 4-15

Chapter 4 Command Listing and Status Information

Status Information

Powerup Status Register Bit Assignments

= Positive Transition

= Negative Transition

= Enable

= Alarm LED

Bit Information Reported Comments P N E A

0 First satellite tracked Condition = 1 when first satellite becomes

tracked following powerup.

1 Oscillator oven warmed up This bit sets when the internal oscillator has

warmed up following powerup.

2 Date & Time Valid This bit sets when first lock is attained after

powerup.

1010

Holdover Status Register Bit Assignments

= Positive Transition

= Negative Transition

= Enable

= Alarm LED

Bit Information Reported Comments P N E A

0 Holding Condition = 1 if in holdover and holding. 1000

1 Waiting Condition = 1 if in holdover and waiting to

recover.

2 Recovering Condition = 1 if in holdover and recovering. 1000

3 User-specified threshold

exceeded

Condition = 1 if in holdover longer than value set by :ROSC:HOLD:DUR:THReshold.

1000

1011

4-16 User’s Guide

Chapter 4 Command Listing and Status Information

Status Information

Hardware Status Register Bit Assignments

= Positive Transition

= Negative Transition

= Enable

= Alarm LED

Bit Information Reported Comments

(NOTE: For every bit in this register, STAT:PRES or SYST:PRES will cause an alarm to be generated if the bit sets)

0 Selftest failure. Sets if something failed during powerup or

user-initiated selftest.

1 +15V supply out of range Continually evaluated during normal operation.

Sets if detected.

2 -15V supply out of range Continually evaluated during normal operation.

Sets if detected.

3 +5V supply out of range Continually evaluated during normal operation.

Sets if detected.

4 Primary oven voltage out of

range

5 Secondary oven voltage out or

range

6 EFC voltage within 5% of limit Continually evaluated during normal operation.

7 EFC voltage at limit Continually evaluated during normal operation.

Continually evaluated during normal operation. Sets if detected.

Sets if detected.

PNEA

1011

8 GPS 1 PPS failure Continually evaluated during normal operation.

Sets if detected.

9 GPS Failure Continually evaluated during normal operation.

Sets if detected.

10 Time Interval Errors have

occurred. This is an event only. (There is no condition information; condition bit will always be 0.)

11 EEPROM write failure. This is

an event only. (There is no condition information; condition bit will always be 0.)

12 Internal Reference Failure Continually evaluated during normal operation.

Continually evaluated during normal operation. Sets if detected. Event only (i.e., condition bit doesn't change).

Sets if there is a failure in any attempt to save information to non-volatile memory

Sets if detected.

User’s Guide 4-17

1011

__11

1011

Chapter 4 Command Listing and Status Information

Information that Appears in the Diagnostic Log

Significant events are logged by the timing Receiver. Each entry contains a brief description of the event and a time of occurrence. See the DIAG:LOG command node for commands that allow control and retrieval of logged information. Listed below are the possible log messages:

Log Message Comments

Log cleared Always becomes first log message when the log is cleared. See

:DIAG:LOG:CLEar.

Power on Indicates Receiver has been powered on.

Re-boot Indicates Receiver processor has re-booted.

Survey mode started Indicates beginning of survey for position.

Position hold mode started Indicates transition from survey to position hold.

GPS lock started Indicates transition into locked operation.

Holdover started, manual Indicates transition to holdover based on user-request.

See :ROSC:HOLD:INITiate.

Holdover started, GPS Indicates transition to holdover due to GPS satellite conditions (e.g., loss

of satellite) or gross problem with GPS 1 PPS.

Holdover started, TI error Indicates transition to holdover due to problem detected with Receiver

ability to properly measure interval between GPS 1 PPS and internal oscillator’s 1 PPS.

Holdover started, TI limit exceeded

Holdover started Indicates transition to holdover for any reason not covered above.

SYST:PRES performed Indicates that the instrument has been preset to factory settings.

System preset indicates that the instrument has been preset to factory settings.

EEPROM save failed Indicates that an attempt to save information to the EEPROM has failed.

Indicates transition to holdover due to the interval from GPS 1 PPS to internal oscillator’s 1 PPS exceeding a limit threshold for numerous measurements. See :ROSC:HOLD:LIM:THReshold.

4-18 User’s Guide

Chapter 4 Command Listing and Status Information

Model for Powerup, Locked, and Holdover States

Figure 4-2 provides a model for thinking about the relationships between powerup, locked, and holdover operation of the Receiver. This model is consistent with commands that allow these states to be evaluated (e.g., see :ROSC:STATe?). Three of the states are part of holdover operation. If the Receiver is in any of these states, the holdover LED will be lit:

• Holding means that the Receiver has been placed in holdover by the user. An explicit command will be required to initiate an exit from holdover.

• Waiting to recover means 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 Recovering state.

• Recovering means that the Receiver is actively working to become locked. All conditions needed to proceed toward locked have been met. Expect an eventual spontaneous transition to locked (unless external conditions change to prevent this, such as loss of tracked satellites).

The other two states are:

• Powerup, indicating that the Receiver hasn't yet achieved GPS lock since it's been powered on. Other queries can provide insight as to the cause if the Receiver is remaining in powerup longer than expected.

• Locked, meaning that the Receiver is locked to GPS. The locked LED will be lit.

Commands that can be used to transition between states are shown in Figure 4-2.

User’s Guide 4-19

Chapter 4 Command Listing and Status Information

Model for Powerup, Locked, and Holdover States

Powerup

ROSC:HOLD:REC:INIT

Holdover Operation

Holding

ROSC:HOLD:INIT

Waiting

ROSC:HOLD:INIT

external conditions

ROSC:HOLD:INIT

Recovering

lock condition

satisfied

lock condition

satisfied

Locked

Recover

external conditions

Figure 4-2. Model of Relationships Between Powerup, Locked, and Holdover Operation of the Receiver

4-20 User’s Guide

Chapter 4 Command Listing and Status Information

Error Messages

Number Error String Cause

+0 No Error The error queue is empty. Every error in the queue has been

read (:SYSTem:ERRor? query) or the queue was cleared by power-on or *CLS.

-100 Command error This is the generic syntax error used if the Receiver cannot detect more specific errors.

-101 Invalid character A syntactic element contains a character that is invalid for that type.

-102 Syntax error An unrecognized command or data type was encountered.

-103 Invalid separator The parser was expecting a separator and encountered an illegal character.

-104 Data type error The parser recognized a data element different than the one allowed. For example, numeric or string data was expected, but block data was received.

-108 Parameter not allowed More parameters were received than expected for the header.

-109 Missing parameter Fewer parameters were received than required for the header.

-112 Program mnemonic too long The header or character data element contains more than twelve characters.

-113 Undefined header The header is undefined. For example, the command “:HELLO”.

-120 Numeric data error This error, as well as errors -121 through -129, is generated when parsing a data element which appears to be numeric. This particular error message is used when the Receiver cannot detect a more specific error.

-121 Invalid character in number An invalid character for the data type being parsed was encountered. For example, a “9” in octal data.

-123 Exponent too large Numeric overflow.

-124 Too many digits The mantissa of a decimal numeric data element contained more than 255 digits excluding leading zeros.

-128 Numeric data not allowed A legal numeric data element was received, but the Receiver does not accept one in this position for the header.

-131 Invalid suffix The suffix does not follow the syntax described in IEEE 488.2 or the suffix is inappropriate for the Receiver.

-134 Suffix too long The suffix contained more than 12 characters.

-138 Suffix not allowed A suffix was encounterd after a numeric element that does not allow a suffix.

User’s Guide 4-21

Chapter 4 Command Listing and Status Information

Error Messages

Number Error String Cause

-141 Invalid character data The character data element contains an invalid character.

-148 Character data not allowed A legal character data element was encountered where prohibited by the Receiver.

-150 String data error This error can be generated when parsing a string data element. This particular error message is used if the Receiver cannot detect a more specific error.

-151 Invalid string data A string data element was expected but was invalid for some reason.

-158 String data not allowed A string data element was encountered but was not allowed by the Receiver at this point in parsing.

-170 Expression error This error can be generated when parsing an expression data element. It is used if the Receiver cannot detect a more specific error.

-178 Expression data not allowed Expression data was encountered but was not allowed by the Receiver at this point in parsing.

-200 Execution error This is the generic syntax error if the Receiver cannot detect more specific errors.

-220 Parameter error Indicates that a program data element error occurred. This error is used when the Receiver cannot detect more specific errors.

-221 Settings conflict Indicates that a legal program data element was parsed but cound not be executed due to the current receiver state.

-222 Data out of range Indicates that a legal program data element was parsed but could not be executed because the interpreted value is outside the legal range defined by the Receiver.

-223 Too much data Indicates that a legal program data element of block, expression, or string type was received that contained more data than the Receiver could handle due to memory or related receiver-specific requirements.

-224 Illegal parameter value Used where exact value, from a list of possible values, was expected (but not received).

-230 Data corrupt or stale No valid data available.

-240 Hardware error Indicates that a legal program command or query could not be executed because of a hardware problem in the Receiver.

-241 Hardware missing Indicates that a legal program command or query could not be executed because of missing receiver hardware.

-300 Device-specific error This is the generic device-dependent error.

-310 System error Indicates that a system error occurred.

-321 Out of memory Indicates that the Receiver has detected that insufficient memory is available.

4-22 User’s Guide

Chapter 4 Command Listing and Status Information

Error Messages

Number Error String Cause

-330 Self-test failed Indicates at least one failure occurred when *TST? or :DIAG:TEST? was executed.

-360 Communication error This is the generic communication error for devices that cannot detect the more specific errors described for errors

-361 through -363.

-361 Parity error in program

message

-362 Framing error in program

message

-363 Input buffer overrun Software or hardware input buffer on serial port overflows

+521 EEPROM failed An attempt to write to EEPROM failed.

Parity bit not correct when data received.

A stop bit was not detected when data was received.

with data caused by improper or nonexistent pacing.

User’s Guide 4-23

Chapter 4 Command Listing and Status Information

Error Messages

4-24 User’s Guide

Specifications Summary

Chapter 5 Specifications Summary

Specifications and Characteristics

The specifications and characteristics of the Z3801A GPS Time and Frequency Reference Receiver are provided in this chapter.

GPS Receiver Features

Six-channel, parallel tracking GPS engine C/A Code, L1 Carrier SmartClock™ technology Enhanced GPS technology

10 MHz Output Characteristics

Frequency Accuracy: < 1 × 10-9 , one day average

Phase Noise:

Offset (Hz) SSB Phase Noise (dBc)

100 -120

1000 -135

10000 -135

Waveform: Sine wave, 1.9 Vp-p into a 50Ω load (typical)

Source Impedance (nominal): 50Ω

Coupling: AC

Connector: BNC

NOTE Complete product specifications are defined by Qualcomm CDMA Land

Network Specification 80-12225.

5-2 User Guide

Chapter 5 Specifications Summary

Specifications and Characteristics

1 PPS Output Characteristics

Jitter of leading edge: < 200 nanoseconds between pulses.

Accumulated time error: < 7 microseconds per day unlocked, for

24 hours, after one day of stabilization and 2 days of locked operation with a fixed antenna location.

Waveform: Pulse width 10 to 50 microseconds.

Time Accuracy: < 1 microsecond (Locked to GPS)

Connector: DB-25 (J3)

Front Panel Indicators (LEDs)

Power (Z3801A has power applied)

Enabled, Active (user-defined operation)

GPS Lock (Z3801A is locked to GPS)

Holdover (Z3801A is operating in holdover mode)

Alarm (indicates an alarm condition)

Remote Interface (Port 1)

RS-422 DTE configuration: Complete remote control and

interrogation of all instrument functions and parameters.

Baud Rate: 19200—7 data bits, 1 start bit, 1 stop bit, odd parity (fixed configuration).

Connectors: 25-pin female rectangular D subminiature (DB-25) on rear panel.

Antenna and Cabling Information

The 58504A Antenna Assembly is recommended to ensure specified performance.

Power Requirements (supplied by the Z3801A): 5 Volts nominal; 50 ma maximum.

Antenna Cable: 200 feet Cables are Belden 9913 with a type N connector one end and a type TNC connector on the other.

User Guide 5-3

Chapter 5 Specifications Summary

Specifications and Characteristics

Environmental

58504A Antenna Assembly

Operating: -40° C to +80° C

Storage: -40° C to +85° C

GPS Time and Frequency Reference Receiver

Operating: 0° C to +50° C

Storage: -40° C to +80° C

Power Requirements

DC Power:

BTS; +27 Vdc nominal (19 Vdc ± 0.5 Vdc to 30 Vdc ± 0.5 Vdc operating

range). Greater than 23 Vdc ± 0.5 Vdc starting.

BSC; -54 Vdc nominal (-60 Vdc ± 0.5 Vdc to -37 Vdc ± 0.5 Vdc operating range). Less than -46 Vdc ± 0.5 Vdc starting.

Input Power (BTS and BSC): < 25 Watts (nominal)

General Information

Dimensions: 127 mm Height × 301.5 mm Width × 345.4 mm Depth.

(Half-Rack Module)

Weight: 3.6 kg

Acceleration: 2g

Power: < 25 Watts

Surge withstand: Meets IEEE/ANSI C37.90, C37.90.1, C37.90.2

Other Information

The standard Z3801A does not include a display or a keypad. While not necessary, it may be convenient to track the Receiver’s progress during installation and startup by monitoring the satellites being tracked, location (position), time and other parameters.

Achieving accurate time of day requires care in determining cable delays, Receiver bias, position (Lat, Lon, Alt), atmospheric conditions, and other parameters which are dependent on each individual installation.

5-4 User Guide

Index

NUMERICS

1 PPS output, 1-2 1 PPS output 1 PPS output synchronization 10 MHz OUT J2 connector 10 MHz output 10 MHz reference output 10811 oven reference oscillator 1 PPS output

, 2-7

, 1-14

, 1-3

, 2-7

, 1-2, 1-14

, 2-9

, 1-3

accessories

available

supplied acquiring GPS lock ACQUISITION Active indicator Alarm Alarm indicator AMP SYMBOL 226 f antenna

cable length delay

delay values

propagation delay ANTENNA and Cabling Information antenna assembly antenna cable antenna cables antenna delay ANTENNA J1 connector Antenna Line Amplifier application note

, ix

, 2-11

, 3-11, 3-14

, 1-2, 2-9

, viii

, 1-2, 1-8, 2-9

, 1-5

, 2-3

, 2-5

, 5-3

, ix

, x, 2-3

, x

, 3-16

, 1-3

, ix

, xi

arrester

lightning, ix azimuth angle

, 3-15

Belden( 8267 cable, 2-3 BTS power supply

, ix

cable

antenna

interconnect, antenna

LMR_400

recommended

RG213 cable assemblies cable length delay cables CDMA Cellular Land Network wireless

base stations chassis ground commands

, x, 2-3

, x

, 2-3

, 1-4, 2-3

, 2-3

, 2-5

, viii, 2-7 , 1-3

, 1-14

commands, examples compensating for antenna cable

delay, 1-15 configuration guide configuration, DCE device or PC

2-10 conformance

, 4-3

SCPI connecting a computer connecting power Coordinated Universal Time (UTC) customer supplied RS-422 interface

cable, 2-10 customizing installation customizing the Receiver operation

DC INPUT J4 connnector, 1-3 dc power connections DCE device

, viii

DCE device configuration dc-power connector wiring delay value delay values

, 2-5

description

holdover, 2-11 description of the HPZ3801A diagnostic log

, 4-18

difficulty

in case of a problem, 2-12 digital communications equipment documents

available, xi

E1 ground stud, 1-3, 1-5 EFC

, 3-18

elevation angle elevation mask angle Enabled indicator environmental information error messages example commands external power supply

features and functions, 5-2 FFOM (Frequency Figure of Merit) FFOM value foldout

, 3-14

, 3-19

foldout, Receiver Status screen

GPS ANTENNA input, 2-3

, 1-14

, xi, 1-4

, 1-8,

, 2-10

, 1-5

, 2-7

, 1-14

, 1-13

, 2-6

, 1-8

, 1-5

, viii

, 3-15

, 1-16, 3-15

, 1-2, 2-9

, 5-4

, 4-21

, 1-14

, 1-5

, 2-11

, 3-19

User Guide Index-1

Index

GPS Lock indicator, 1-2, 2-9 GPS status GPS time ground plane ground stud guide organization

, 1-9

, 3-16

, ix

, 1-3

, vii

HEALTH MONITOR, 3-11 health monitor screen height

, 1-17

help from HP

, 1-4, 2-4

Hold position mode holdover

tutorial

, 2-9, 3-12

, 3-8

holdover description Holdover indicator holdover mode

, viii, 2-7

holdover operation holdover state

, 4-19

Holdover Status Register holdover threshold How to use the Status Screen HP 10811 oven oscillator HP 58506A 50ft Cable

, 3-11

, 3-17

, 2-11

, 1-2, 2-9

, 3-8

, 4-16

, 3-14

, 3-4

, 2-9

, x

HP 58509A antenna line amplifier HP 58518A/519A cable HP 58518AA/519AA cable HP 58520A/521A cable HP 58520AA/521AA cable HP SmartClock HP_SatStat

operating

, 1-11, 3-3 , 1-12

HP_SmartClock HP_SmartClock compensation

, 2-5

, 2-6

, 2-9

, 3-11

, 2-7

HP_Z3801A GPS Receiver

Commands

, 4-2

I/O Port 1 J3 connector, 1-3

, 3-15

Ignore in case of a problem indicator

Active, 1-2, 2-9

, 1-2, 1-8, 2-9

Alarm Enabled GPS Lock Holdover Power

indicators

, 1-2, 2-9

, 1-2, 1-8, 2-9

, 2-9

input

antenna, 2-3 POWER

, 2-3, 2-6

Input/Output (I/O) INSTALL Commands installing HP_SatStat interconnect cables

, 2-12

, 2-8

, 4-4

, 1-11

, x

, ix

interface cable, 2-10 internal reference oscillator

, 1-2, 2-9

latitude, 1-17 LED

, 1-2, 2-9

Active Alarm

, 1-2, 1-8, 2-9

Enabled GPS Lock Holdover

Power Light-Emitting Diodes lightning arrester line amplifier line amplifier requirements list of options LMR cables LMR_400 cable local time local time zone locked state longitude

, 1-2, 2-9

, 1-2, 1-8, 2-9

, viii

, ix

, 2-4

, ix

, 1-4

, 2-3

, 1-16

, 3-16

, 4-19

, 1-17

manuals, xi messages

diagnostic log, 4-18 Model for Powerup, Locked, and Holdover

, 4-19

States

not tracking., 3-15

obtaining GPS status, 1-9 One Pulse Per Second Operation Status Register

, ix

options

, 2-7

, 4-15

output

1 PPS, 2-7

10 MHz

, 2-7

plug, dc-power connector, 1-5 Position position survey power connection Power indicator POWER input jack power requirements powering up the Receiver power-on self test power-up procedure powerup state Powerup Status Register PRIMARY Commands propagation delay

, 3-17

, 1-15

, 1-5

, 1-2, 1-8, 2-9

, 2-3, 2-6

, 5-4

, 1-6

, 1-8

, 1-6

, 4-19

, 4-16

, 4-4

, 2-5

Index-2 User Guide

Index

pseudorandom noise, 3-15

quality

FFOM

, 3-14

, 3-13, 3-14

signal

, 3-13

TFOM

Questionable Status Register

, 4-15

rack mount tray, ix reading Receiver Status screen rear-panel RS-422 Serial Port/10 MHz/

1PPS connection wiring, 2-8

receiver

antenna cable delay

compensation

, 1-15

command syntax conventions controlling functions via

commands, 1-14 customizing operation degraded timing performance diagnostic log

, 4-18

elevation mask angle error messages grounding

, 4-21

, 1-3

HP_SatStat installation INSTALL commands messages, diagnostic log messages, error position survey power input

, 4-21

, 1-15

, 1-3

power-on event sequence power-on self test

, 1-8

PRIMARY commands relationships between powerup, locked,

and holdover operation, 4-20 RS-422 serial port

, 1-3

RS-422 serial port, specifications serial-port configuration specifications and characteristics status information

Receiver Status screen

, 4-14

, 3-3, 3-11

Receiver Status Screen at a Glance Recovery recovery from Holdover RG213 cable RG213 cables RS-232 cables supplied

, 3-12

, 3-10

, 2-3

, 1-4

RS-422 interface cable, customer

supplied

RS-422 serial port

, 2-10

, ix, 1-9, 2-8

RS-422 serial port, specifications RS-422 serial-port configuration

values, 1-8, 2-10

, 3-11

, 4-3

, 1-9, 1-13

, 1-16

, 1-11

, 4-4

, 4-18

, 1-8

, 4-4

, 5-3

, 1-8, 2-10

, 5-2

, 3-19

, 5-3

Safety Earth Ground, 1-3 sample status screen Satellite Status

, 1-10, 3-11

, 3-15

SCPI

conformance, 4-3

version Self Test serial interface

, 4-3

, 3-18

, 1-3

serial-port configuration values signal

quality, 3-13, 3-14 signal strength SmartClock SmartClock Mode SmartClock’s PLL specifications

HP Z3801A Standard Event Register

, 3-15

, 2-9

, 3-12

, 3-14

, 5-2

, 4-14

Status Registers

Hardware Status, 4-17

Holdover Status

Operation Status

Powerup Status

Questionable Status

simplified relationships

Standard Event status screen strength of the signal Survey position mode survey using command SYNCHRONIZATION

, 4-16

, 4-15

, 4-16

, 4-15

, 4-14

, 3-4, 3-11

, 3-15 , 3-17

, 1-15

, 3-11

SYSTEM

PRESET command

STATUS?

, 4-11

STATUS? command

, 1-14

, 1-9

terminal emulation program, 1-7 TFOM value

, 3-13

Time and Frequency Reference

Receiver

, viii

Timing Receiver Windows User

Interface, 1-7 timing shift troubleshooting tutorial

using the Status Screen

, 3-14

, 2-12

, 3-3

, 3-4

user interface, ix

, 2-7

UTC UTC (USNO) UTC time

, 2-7

, 1-16, 3-16

Windows, 1-9

, 1-8

User Guide Index-3

Index

wiring, dc-power input, 1-5

Index-4 User Guide

Symmetricom Z3801A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents

In This Guide

Guide Organization

Options

Accessories Supplied and Available

Manuals

Getting Started

Z3801A Front Panel at a Glance

Z3801A Rear Panel at a Glance

Preparing the GPS Receiver for Use

Powering Up the Receiver

Installing the Automated SatStat Program for Continual Status Updates

Operating the Automated SatStat Program

Customizing the Receiver Operation

Using Commands to Control Key Functions (Examples)

Features and Functions

Chapter Contents

Inputs

Outputs

Indicators

Connecting to a Computer

Operating Concepts

In Case of a Problem

Using the Receiver Status Screen

Chapter Contents

Using and Reading the Receiver Status Screen

Receiver Status Screen Data

The Receiver Status Screen at a Glance

Command Listing and Status Information

Chapter Contents

Z3801A Commands

Status Information

Information that Appears in the Diagnostic Log

Model for Powerup, Locked, and Holdover States

Error Messages

Specifications Summary

Specifications and Characteristics

Index