Acutime™2000 Synchronization Kit User Guide F Part Number 45005-00-ENG Revision A April 2001
Corporate Office Copyright and Trademarks Trimble Navigation Limited © 2001, Trimble Navigation Limited. All rights reserved. No part of this manual may be 645 North Mary Avenue Post Office Box 3642 Sunnyvale, CA 94088-3642 U.S.A. Phone: +1-408-481-8940, 1-800-545-7762 Fax: +1-408-481-7744 www.trimble.com copied, reproduced, translated, or reduced to any electronic medium or machine-readable form for any use other than with the Acutime™ 2000 GPS Smart Antenna, or Acutime 2000 Synchronization Kit.
Software and Firmware License, Limited Warranty This Trimble software and/or firmware product (the “Software”) is licensed and not sold. Its use is governed by the provisions of the applicable End User License Agreement (“EULA”), if any, included with the Software. In the absence of a separate EULA included with the Software providing different limited warranty terms, exclusions, and limitations, the following terms and conditions shall apply.
TRIMBLE NAVIGATION LIMITED IS NOT RESPONSIBLE FOR THE OPERATION OR FAILURE OF OPERATION OF GPS SATELLITES OR THE AVAILABILITY OF GPS SATELLITE SIGNALS. Limitation of Liability TRIMBLE’S ENTIRE LIABILITY UNDER ANY PROVISION HEREIN SHALL BE LIMITED TO THE GREATER OF THE AMOUNT PAID BY YOU FOR THE PRODUCT OR SOFTWARE LICENSE OR U.S.$25.00.
Contents About This Manual Scope and Audience . . . . . . . . . . . Organization . . . . . . . . . . . . . . . Reader Feedback . . . . . . . . . . . . . Related Information . . . . . . . . . . . Update Notes . . . . . . . . . World Wide Web (WWW) Site Technical Assistance. . . . . . Abbreviations . . . . . . . . . . . . . . . Document Conventions . . . . . . . . . . Cautions and Notes . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents 3 Acutime 2000 Installation 3.1 3.2 3.3 3.4 4 4.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 3-4 3-5 3-6 Interface and Power Connections. . . . . . . . . . . Interface Cables and Connectors . . . . . . . . . . . 4.2.1 Pin-Outs . . . . . . . . . . . . . . . . . . Connection Instructions . . . . . . . . . . . . . . . 4.3.1 Power Connection (Red and Black Wires) 4.3.2 Timing Pulse Connections . . . . . . . . . 4.3.
Contents 5.5 5.6 6 Using the Acutime 2000 in Mobile Applications . . . . . . . . . 5-15 Customizing Acutime 2000 Operations . . . . . . . . . . . . . . 5-16 NTP Software Installation and Configuration 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Network Time Protocol. . . . . . . . . . . . . . . 6.1.1 NTP Time Servers . . . . . . . . . . . . Software Sources and Compatibility . . . . . . . . 6.2.1 Installation Support . . . . . . . . . . . Pre-Installation Check List . . . . . . . . . . . . . 6.3.1 GPS Preparation .
Contents 6.8 A viii Monitoring NTP . . . . . . . . . . . . . . 6.8.1 NTP Events on Windows NT . . 6.8.2 UNIX System Log Files . . . . . 6.8.3 NTPQ – The NTP Query Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-31 .6-32 .6-34 .6-35 A.1 Interface Scope . . . . . . . . . . . . . . . . . . . . . A.1.1 Packet Structure . . . . . . . . . . . . . . . A.2 Physical Interface Characteristics . . . . . . . . . . . A.2.1 Nomenclature . . . . .
Contents B Timing Receiver Monitor B.1 B.2 C NMEA 0183 C.1 C.2 C.3 C.4 D Start-Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 Main screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2 The NMEA 0183 Communication Interface . . . . . . . . . NMEA 0183 Message Format . . . . . . . . . . . . . . . . NMEA 0183 Message Options . . . . . . . . . . . . . . . . NMEA 0183 Message Formats. . . . . . . . . . . . . . . . C.4.1 GGA – GPS Fix Data . . . . . . . . . . . . . . .
Contents E.3 E.4 E.5 F E.2.4 Running NTP with Event Polling Disabled E.2.5 Incorrect Port and Bad Data . . . . . . . . E.2.6 Serial Port is Unavailable . . . . . . . . . Compiling the NTP Distribution . . . . . . . . . . . Windows NT Administration . . . . . . . . . . . . . E.4.1 Controlling the NTP Service . . . . . . . E.4.2 Removing the NTP Service . . . . . . . . Additional Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of Figures Figure 1-1 Figure 2-1 Figure 3-1 Figure 4-1 Figure 4-2 Figure 5-1 Figure 5-2 Figure 6-1 Figure 6-2 Figure 6-3 Figure 6-4 Figure D-1 Figure D-2 Figure F-1 Figure F-2 Acutime 2000 GPS Smart Antenna Enclosure . . . . . . Connection Diagram . . . . . . . . . . . . . . . . Mounted Antenna . . . . . . . . . . . . . . . . . Acutime 2000 Interface Connector . . . . . . . . . . Acutime 2000 12-pin Connector format. . . . . . . . . PPS Quantization Error . . . . . . . . . . . . . . .
List of Figures xii Acutime 2000 Synchronization Kit User Guide
List of Tables Table 4-1 Table 4-2 Table 4-3 Table 5-1 Table 5-2 Table 5-3 Table 5-4 Table 5-5 Table 5-6 Table 5-7 Table 5-8 Table 5-9 Table 6-1 Table A-1 Table A-2 Table A-3 Table A-4 Table A-5 Table A-6 Table A-7 Table A-8 Table A-9 Table A-10 Mating Connectors . . . . . . . . . . . . . . . Acutime 2000 RS-422 Cable Pin-Out . . . . . Acutime 2000 RS-232 Cable Pin-Out . . . . . Default Satellite Mask Settings. . . . . . . . . Receiver Configuration (segment 2) . . . . . . OEM Configuration (segment 3) . .
List of Tables Table A-11 Table A-12 Table A-13 Table A-14 Table A-15 Table A-16 Table A-17 Table A-18 Table A-19 Table A-20 Table A-21 Table A-22 Table A-23 Table A-24 Table A-25 Table A-26 Table A-27 Table A-28 Table A-29 Table A-30 Table A-31 Table A-32 Table A-33 Table A-34 Table A-35 Table A-36 Table A-37 Table A-38 Table A-39 Table A-40 xiv Satellite Data Packets. . . . . . . . . . . . . . . . . . . . Customizing Receiver Operations . . . . . . . . . . . . . Advanced Packets . . . . . . . . . . . .
List of Tables Table A-41 Table A-42 Table A-43 Table A-44 Table A-45 Table A-46 Table A-47 Table A-48 Table A-49 Table A-50 Table A-51 Table A-52 Table A-53 Table A-54 Table A-55 Table A-56 Table A-57 Table A-58 Table A-59 Table A-60 Table A-61 Table A-62 Table A-63 Table A-64 Table A-65 Table A-66 Table A-67 Table A-68 Table A-69 Table A-70 Report Packet 4B . . . . . . . . . . . . . . . . . . . . . Byte 1 Bit Encoding – Status 1 . . . . . . . . . . . . . . Report Packet 4C . . . . . . . . . . . . . . .
List of Tables Table A-71 Table A-72 Table A-73 Table A-74 Table A-75 Table A-76 Table A-77 Table A-78 Table A-79 Table A-80 Table A-81 Table A-82 Table A-83 Table A-84 Table A-85 Table A-86 Table A-87 Table A-88 Table A-89 Table A-90 Table A-91 Table A-92 Table A-93 Table A-94 Table A-95 Table A-96 Table A-97 Table A-98 Table A-99 Table A-100 xvi Command Packet 8E-14 . . . . . . . . . . . . . . . . Command Packet 8E-14 . . . . . . . . . . . . . . . . Command Packet 8E-20 . . . . . . . . . . . . . . . .
List of Tables Table A-101 Table C-1 Table C-2 Table C-3 Table C-4 Table C-5 Table C-6 Table C-7 Table C-8 Table C-9 Table D-1 Table D-2 Table D-3 Table D-4 Table D-5 Table E-1 Table E-2 Table F-1 Datums . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NMEA 0183 Characteristics . . . . . . . . . . . . . . . . . . Acutime 2000 NMEA Messages . . . . . . . . . . . . . . . . GGA – GPS Fix Data Message Parameters . . . . . . . . . . GLL – Geographic Position – Latitude / Longitude Message Parameters .
List of Tables xviii Acutime 2000 Synchronization Kit User Guide
About This Manual Welcome to the Acutime™ 2000 Synchronization Kit User Guide. This manual describes how to integrate the Acutime 2000 smart antenna with your host system. ! Note – The Acutime 2000 has replaced the Palisade™ and Palisade Network Time Protocol (NTP). It can be used with NTP (See Chapter 6) or as a stand-alone timing receiver. In some instances the term Palisade is still used in the screen captures and text in this manual. This will be updated in future revisions.
About This Manual Organization This manual contains the following: xx • Chapter 1, Introduction, describes the Acutime 2000 GPS smart antenna. • Chapter 2, Getting Started, describes how to quickly install, connect and operate the Acutime 2000. • Chapter 3, Acutime 2000 Installation, provides general installation guidelines. • Chapter 4, Acutime 2000 Connections, provides detailed interfacing guidelines for connecting the Acutime 2000 GPS smart antenna to the host system.
About This Manual • Appendix F, Theory of Operation, gives a more detailed technical description of many of the Acutime 2000 GPS smart antenna's operating characteristics. A brief overview of the system architecture is also presented. • The Glossary contains definitions of GPS and technical terms used in this manual. Reader Feedback Your feedback about the product documentation helps us to improve it with each revision.
About This Manual Related Information The following sections discuss other sources of information that introduce, extend, or update this manual. Update Notes If any changes are made to the firmware, update notes and firmware are posted to the Trimble Web site. World Wide Web (WWW) Site For more information about Trimble, visit our site on the World Wide Web: • xxii www.trimble.
About This Manual Technical Assistance If you have a problem and cannot find the information you need in the product documentation, contact your sales representative. Alternatively, request technical support via email at trimble_support@trimble.com or by phone at 1-800-767-4822.
About This Manual Cautions and Notes Cautions, notes, and tips draw attention to important information and indicate its nature and purpose. " ! # xxiv Caution – Cautions describe operating procedures and practices required for correct operation and alert you to situations that could cause hardware damage or malfunction or software error. Note – Notes give additional significant information about the subject to increase your knowledge, or guide your actions.
1 Introduction This chapter provides an overview of the Acutime 2000 GPS smart antenna. 1.1 Overview The Acutime 2000 is the latest in the Trimble family of GPS smart antennas. The smart antenna allows OEMs and systems integrators to add GPS capability to their product lines quickly and easily, without becoming GPS experts. The Trimble Acutime 2000 GPS smart antenna encompasses the experience of four product lines: Acutis™, Acutime™, Acutime™ II and Palisade™.
1 Introduction To integrate the Acutime 2000, the OEM only needs to add a standard serial interface port on the host system and develop a software interface. Commonly used interface protocols, such as NMEA 0183, and the software interface tool (the Timing Receiver Monitor), simplify this task, minimizing the engineering costs associated with integrating the Acutime 2000. 1.
1 Introduction • a waterproof, UV-resistant, plastic (polycarbonate) enclosure with a proven epoxy seal. (The enclosure is illustrated in Figure 1-1). Figure 1-1 Acutime 2000 GPS Smart Antenna Enclosure Acutime 2000 generates a PPS synchronized to UTC within 50 nanoseconds (one sigma). This level of precision is obtained using an overdetermined time solution, an 80-nanosecond pulse steering resolution and a T-RAIM (Time-Receiver Autonomous Integrity Monitor) algorithm.
1 Introduction 1.3 Starter Kit The Acutime 2000 Synchronization Kit includes the following: • Acutime 2000 with RS-422 interface and 8-channel receiver • Acutime 2000 User Guide • 100’ interface cable with DB25 connectors • RS-422 to RS-232 converter • Timing Receiver Monitor software • Power Supply For information about Acutime 2000 interface cables, see Chapter 4, Acutime 2000 Connections. For information about part numbers, refer to: • 1-4 www.trimble.
2 Getting Started This chapter describes how to quickly install, connect and communicate with the Acutime 2000 GPS Smart Antenna. ! Note – For permanent installations, see the instructions in Chapter 3.
2 Getting Started • A mounting pole The Acutime 2000 accepts a standard 1"-14 straight thread. 2.1 Connecting the Smart Antenna The Acutime 2000 can be placed anywhere with a clear view of the sky. Connect the interface cable to the smart antenna. The connector on the interface connector has a locking ring for securing the connection.
2 Getting Started 2.2 Connecting the Computer and Power Source The connection instructions illustrated in Figure 2-1 assume use of the Trimble interface cable included in the Synchronization Kit. If you are using your own cable, modify the instructions accordingly. Wall Power Acutime 2000 Synchronization Interface Module (RS-422 to RS-232 converter) PPS Port A Port B PC (primary port) Port A (The starter kit includes only one cable.
2 Getting Started 2.3 Communicating with the Acutime 2000 When power is applied, the Acutime 2000 acquires a valid set of satellites and automatically transmits position and time messages. During the satellite acquisition process, the Acutime 2000 outputs periodic status messages. To begin communicating with the Acutime 2000, start the Timing Receiver Monitor program. Data fields in the Timing Receiver Monitor program fill up as the data becomes available.
3 Acutime 2000 Installation This chapter provides installation guidelines for the Acutime 2000 GPS smart antenna. Installation of the Acutime 2000 requires four steps: 1. Choosing a location. 2. Mounting the smart antenna. 3. Routing and securing the interface cable. 4. Connecting the host system. Each of these installation steps is described on the following pages.
3 Acutime 2000 Installation 3.1 Choosing a Location Select an outdoor location for the antenna (such as the roof of your building) that has a relatively unobstructed view of the sky. Consider the length of the cable run and the length of the interface cable when selecting a location. The Acutime 2000 GPS smart antenna is designed for a pole mount. (The mounting pole is not included with the Acutime 2000.) Pole mounting is illustrated in Figure 3-1.
3 Acutime 2000 Installation The antenna can receive satellite signals through glass, canvas, and thin fiberglass, but dense wood, concrete and metal structures shield the antenna from satellite signals. The Acutime 2000 GPS smart antenna contains an active antenna. For optimal performance, place it as far as possible from transmitting antennas, including radars, satellite communication equipment and cellular transmitters.
3 Acutime 2000 Installation 3.2 Mounting the Smart Antenna The smart antenna is designed for a pole mount, as illustrated in Figure 3-1. The threaded socket in the base of the antenna accepts a standard 1"-14 straight thread. A wide variety of 1"-14 pole mounts are available from marine hardware suppliers. After obtaining an appropriate mounting pole, follow these simple steps to install the Acutime 2000 GPS smart antenna. " 1.
3 3.3 Acutime 2000 Installation Routing and Securing the Interface Cable After the smart antenna is mounted: 1. ! Route the interface cable from the smart antenna to the host location. Note – The interface cable is a digital cable, so it can be spliced and extended, if necessary. Choose the most direct path to the host system, while avoiding the following hazards: • • • • • • 2.
3 Acutime 2000 Installation 3.4 Connecting the Host System The final step, if applicable, is the installation of the connector on the host end of the cable. The connector installation instructions depend on the type of connector required by the host system. For information on pin-outs, see Chapter 4, Acutime 2000 Connections.
4 Acutime 2000 Connections This chapter provides instructions on connecting the Acutime 2000 to the host system and power source.
4 Acutime 2000 Connections 4.1 Interface and Power Connections The black plastic connector located in the base of the Acutime 2000 supports both the interface and power connections. The Acutime 2000 uses a 12-pin connector. Figure 4-1 illustrates the location of the connector.
4 Acutime 2000 Connections Figure 4-2 illustrates the pin arrangement for this connector.
4 Acutime 2000 Connections 4.2 Interface Cables and Connectors Interface cables for the Acutime 2000 are available in the following standard lengths. • 50' (15-meter) • 100' (30-meter) • 200' (60-meter) • 400' (120-meter) Contact Trimble for custom-length cables up to 300 m. For a list of part numbers, refer to: • www.trimble.
4 Acutime 2000 Connections 4.2.1 Pin-Outs Table 4-2 lists the pin-out descriptions and color codes for the standard interface cables.
4 Acutime 2000 Connections Table 4-3 Acutime 2000 RS-232 Cable Pin-Out Signal Description Wire Color Protocol Acutime 2000 Connector DC Power Red +8 to +36V Pin 1 Port B: RS-232 Receive Violet TSIP RS232 Pin 2 Not Used Orange Not Used Pin 3 Port B: RS-232 Transmit Brown TSIP RS232 Pin 4 Not Used Yellow Not Used Pin 5 Port A: RS-232 Receive White Event Input/RTCM Pin 6 Port A: RS-232 Transmit Gray TSIP RS232 Pin 7 Vback Green Battery Backup Pin 8 DC Ground Black Grou
4 Acutime 2000 Connections 4.3 Connection Instructions This section provides detailed information for connecting the Acutime 2000's power, timing pulse and data packet lines. 4.3.1 Power Connection (Red and Black Wires) The red wire (Acutime 2000 pin #1) and black wire (Acutime 2000 pin #9) in the interface cable support the power and ground connections, respectively. The Acutime 2000 features a switching DC power supply, which accepts from 8 to 36 volts.
4 Acutime 2000 Connections For more information on using the timing pulse, see Chapter 5, System Operation. 4.3.3 Serial Port Connections The recommended use of the serial ports on the Acutime 2000 for most users is as follows: • Use Port B to configure the Acutime 2000 as necessary. • Disable the automatic output packets on Port B using command packet 8E-A5. • Use Port B to transmit the desired timing packet. • Use Port B to query for specific satellite data as needed.
4 Acutime 2000 Connections TSIP timing packets 8F-0B, 8F-AB and 8F-AC (which work together as a pair of packets) or 8F-AD can be enabled on Port B using command packet 8E-A5. These packets are sent within 30 milliseconds after the PPS pulse when enabled. By default, the Acutime 2000 automatically sends a variety of satellite data packets on Port B that you may not need. You can disable these automatic output packets with command packet 8E-A5 so that only the timing packets are sent.
4 Acutime 2000 Connections ! 4-10 Note – These Port A pins are shared between the external event input and serial RTCM message inputs. When differential GPS is enabled, this input is set up to receive RTCM messages. When differential GPS is off, this input is set up to receive external event signals.
5 System Operation This chapter describes the operating characteristics of the Acutime 2000 GPS smart antenna, including start-up, satellite acquisition, operating modes, serial data communication, and the timing pulse. The Acutime 2000 acquires satellites and computes position and time solutions. It outputs data in the TSIP (or NMEA) protocol through its serial ports. For more technical information on system operation, see Appendix F, Theory of Operation . 5.
5 System Operation 5.2 Automatic Operation When the Acutime 2000 has acquired and locked onto a set of satellites that pass the mask criteria listed below, and has obtained a valid ephemeris for each satellite, it performs a self-survey. After a number of position fixes, lasting approximately 40 minutes, the selfsurvey is complete. At that time, the Acutime 2000 automatically switches to a time-only mode and periodic outputs of navigation information cease. 5.2.
5 System Operation SNR Mask Although the Acutime 2000 is capable of tracking signals with SNRs as low as 2, the default SNR mask is set to 4 to eliminate poor quality signals from the fix computation. Low SNR values can result from: • • • low-elevation satellites partially obscured signals (for example, dense foliage) multi-reflected signals (multipath) Multi-reflected signals, also known as multipath, can degrade the position solution.
5 System Operation 5.2.2 Tracking Modes The Acutime 2000 operates in one of two main fix modes: • • Self-Survey (Position fix mode) Overdetermined Clock mode After establishing a reference position in Self-Survey mode, the Acutime 2000 automatically switches to Overdetermined (OD) Clock mode. Self-Survey Mode At power-on, the Acutime 2000 performs a self-survey by averaging 2000 position fixes. The number of position fixes until survey completion is configurable using the 8E-4B or 8E-A9 command.
5 System Operation Overdetermined Clock Mode Overdetermined Clock Mode is used only in stationary timing applications. This is Acutime 2000's default mode. After the Acutime 2000 self-surveys its static reference position, it automatically switches to Overdetermined Clock Mode and determines the clock solution. The timing solution is qualified by a T-RAIM algorithm, which automatically detects and rejects faulty satellites from the solution.
5 System Operation 5.2.3 PPS Output Options The PPS (Pulse Per Second) output is the primary timing output generated by the Acutime 2000. In all configurations of the product, the PPS output is provided through a RS-422 differential driver. Although using a RS-422 differential receiver to receive the PPS provides the best noise immunity, you can use just one side of the differential signal for single-ended applications. You can program the characteristics of the PPS output using TSIP packets.
5 System Operation 5.2.4 PPS Quantization Error The Acutime 2000 uses a high-precision, fixed-frequency oscillator as the timing source to down-convert and decode the GPS signal and to generate the PPS output signal. Since a fixed-frequency oscillator is used, the Acutime 2000 must place the PPS output on the clock edge that it determines is closest to UTC or GPS.
5 System Operation Figure 5-2 illustrates the result of removing the quantization error from the PPS output in a user system. The top plot shows the offset of the PPS output pulse relative to a stable standard such as a Cesium atomic clock. The quantization error is responsible for the jagged appearance of the waveform. The middle plot shows the quantization error as reported by the Acutime 20000 in packet 0x8F-AC. The bottom plot is the result of subtracting the quantization error from the PPS offset.
5 System Operation 5.2.5 External Event Input The Acutime 2000 provides an External Event Input that allows the user to time tag external event pulses. The event capture mechanism is triggered on the low-to-high transition of the external event input. The time tag provides a resolution of 320 nanoseconds and represents the time at which the event pulse occurred at the Acutime 2000 connector input. Therefore, it is offset by the amount of delay in the cable.
5 System Operation 5.3 Serial Data Communication When the Acutime 2000 has acquired a set of satellites that conforms to the mask and mode settings and has collected a valid ephemeris for each satellite, it automatically commences periodic outputs of GPS data and generates a timing pulse (PPS). 5.3.1 Port B The Acutime 2000 outputs periodic TSIP health, mode, and time messages on Port B. These status messages confirm that the receiver is working.
5 System Operation 10 Hertz rate. Use packet 8E-A5 to configure this port to output the 8F-0B (or 8F-AD) packet in response to external events.
5 System Operation 5.4 GPS Timing In many timing applications, such as time/frequency standards, site synchronization systems, wireless voice and data networks, and event measurement systems, GPS receivers are used to steer a local reference oscillator. The steering algorithm combines the short-term stability of the oscillator with the long-term stability of the GPS PPS.
5 System Operation GPS time accuracy is affected by the same major source of error that affects position accuracy: Selective Availability (S/A). The position and time errors are related by the speed of light. Therefore, a position error of 100 meters corresponds to a time error of approximately 333 nanoseconds. The GPS receiver's clocking rate and software affect PPS accuracy. The Acutime 2000’s 12.5 MHz clocking rate enables a steering resolution of 80 ns (±40 ns).
5 System Operation Timing Pulse Output (PPS) A pulse-per-second (PPS), 1 microsecond-wide pulse is available on the Acutime 2000’s interface connector. The pulse is sent once per second and the leading edge of the pulse is synchronized to UTC or GPS time. The pulse shape is affected by the distributed capacitance of the attached cabling and input circuit. The leading edge is typically less than 20 nanoseconds wide. The pulse's trailing edge should never be used for timing applications.
5 5.5 System Operation Using the Acutime 2000 in Mobile Applications Although it is intended primarily for use in static applications, the Acutime 2000 can also be used in mobile applications. The factory default settings for the Acutime 2000 assume that the antenna is going to be used in a static timing application. To use the Acutime 2000 in mobile applications, you must disable the Acutime’s selfsurvey mechanism and ensure that a stored position does not exist in the nonvolatile EEPROM.
5 System Operation 5.6 Customizing Acutime 2000 Operations The Acutime 2000 provides a number of user configurable parameters that allow you to customize the operation of the unit. These parameters are stored in a non-volatile memory chip (EEPROM) to be retained during loss of power and through resets. At reset or power-up, the Acutime 2000 configures itself based on the parameters stored in the EEPROM.
5 Table 5-2 System Operation Receiver Configuration (segment 2) Parameter Factory default Set Request Report Operating dimension 4 (Full Position 3D) BB BB BB DGPS mode 3 (Auto DGPS/GPS) BB BB BB Dynamics code 1 (Land) BB BB BB Elevation mask 0.175 radians (10 degrees) BB BB BB Signal level mask 4.0 AMU BB BB BB PDOP mask 8.0 BB BB BB PDOP switch 6.
5 System Operation Table 5-4 Port A and B Configuration (segment 4) Parameter Factory default Set Request Report Input baud rate 9600 BC BC BC Output baud rate 9600 BC BC BC Parity Odd BC BC BC Data bits 8 BC BC BC Stop bits 1 BC BC BC Input protocol none BC BC BC Output protocol TSIP BC BC BC Table 5-5 PPS Configuration (segment 5) Parameter Factory default Set Request Report PPS enabled switch Enabled 8E-4A 8E-4A 8E-4A PPS timebase UTC 8E-4A 8E-4A
5 Table 5-7 System Operation Self-Survey Configuration (segment 7) Parameter Factory default Set Request Report Survey enable flag TRUE 8E-A6 8E-A6 8F-A6 Survey length 2000 8E-A6 8E-A6 8F-A6 Survey save flag FALSE 8E-A6 8E-A6 8F-A6 Survey operating dimension Full Position 3D 0xBB 0xBB 0xBB The survey operating dimension can be set to auto and 2D if segments are saved (8E-26) while a survey is in process. The receiver uses the dimension setting saved for the next survey.
System Operation 5-20 5 Acutime 2000 Synchronization Kit User Guide
6 6.1 NTP Software Installation and Configuration Network Time Protocol The Network Time Protocol (NTP) is a family of programs that are used to adjust the system clock on your computer and keep it synchronized with external sources of time. NTP was developed by Dr. David Mills at the University of Delaware. Information is available at the official NTP web site: www.eecis.udel.
NTP Software Installation and Configuration ! 6.1.1 6 Note – The Acutime 2000 has replaced the Palisade and Palisade NTP. It can be used with NTP or as a stand-alone timing receiver. In some instances the term Palisade is still used in the screen captures and text in this manual. This will be updated in future revisions. NTP Time Servers A primary network time server is a networked computer connected to an accurate external source of reference time.
6 6.2 NTP Software Installation and Configuration Software Sources and Compatibility The list of systems supporting the Acutime NTP reference clock is continuously growing. For updated information, see the Trimble web site at www.trimble.com/oem/ntp. For the latest documentation for the Acutime driver, or if Acutime NTP reference clocks are not supported by the version of NTP shipped with your operating system, see the Trimble FTP site at ftp://ftp.trimble.com/pub/ntp.
NTP Software Installation and Configuration 6.2.1 6 Installation Support Trimble is attempting to provide the best possible support for customers who use the Acutime NTP Synchronization Kit to transfer time to NTP hosts. Due to the wide variety of systems, peripherals, and associated configurations, Trimble is not able to provide assistance installing and testing NTP.
6 NTP Software Installation and Configuration 6.3.1 GPS Preparation • ! ! Perform the checkout, installation and connection instructions in chapters 1–4. Note – Temporary installations, as described in Chapter 2, can be used to establish functionality of NTP, but reliable performance cannot be achieved until the Acutime smart antenna is properly installed with clear view of the sky. • The Acutime and Synchronization Interface Module should be powered up.
NTP Software Installation and Configuration 6.3.2 6-6 6 Host System Preparation • Installation of NTP must be performed by a user with administrative or super-user privileges. • Network Time Protocol can not coexist with other clock synchronization utilities, such as the TimeServ utility available in the Microsoft Windows NT Resource Kit. Any other time synchronization utility running on the host system must be stopped, disabled or de-installed.
6 NTP Software Installation and Configuration 6.3.3 Operating System Specific Information This documentation is applicable to Windows NT and UNIX Installation. Separate instructions for the different operating systems are provided where required.
6 NTP Software Installation and Configuration 6.4 Time Transfer Cable Connection The serial port of the host computer serves as a precision synchronization interface between NTP and the Acutime smart antenna. Connect Port A on the Acutime Synchronization Interface Module, to the NTP time server’s serial port, as shown in Figure 6-1. Trimble provides a standard DB-9 serial cable with the Acutime NTP Synchronization Kit.
6 NTP Software Installation and Configuration 6.4.1 Optional Connections Port B and the PPS output of the Synchronization Interface Module are not currently used by the Acutime NTP reference clock driver, and do not require connection. They are available for other applications, such as backup timing interfaces on the time server.
NTP Software Installation and Configuration 6.5 6 NTP Software Installation NTP software installation consists of copying the NTP program and utilities to the host system’s fixed disk, and configuring the system to start NTP after booting. The same NTP software can be used on servers and client workstations. This versatility allows efficient reconfiguration of time servers to function with the Acutime NTP reference clock if necessary.
6 NTP Software Installation and Configuration 6.5.1 NTP Configuration File The NTP configuration file, NTP.CONF, is a human readable text file which contains information about security settings, time servers and reference clocks. NTP reads the information in this file at startup, and initializes itself according to the configuration entries. The order of the line items in the configuration file is arbitrary. You must edit the configuration file for the serial port connection on your system.
NTP Software Installation and Configuration 6.5.2 6 Acutime Configuration The following line must be found in the NTP configuration file to declare an external Acutime NTP reference clock: server 127.127.29.x The prefix 127.127.29 uniquely identifies the Acutime NTP reference clock. The last number, represented by x, represents the reference clock unit number. Unit Number The unit number identifies the physical serial port to which Acutime is connected.
6 NTP Software Installation and Configuration 6.5.3 Network Server Selection To complete the configuration file, you need to define additional sources of time for the server. Each time server on the network should have at least three independent clock references to function optimally. In large organizations there may already be network time servers in operation. Consult your system administrators for their names or IP numbers.
NTP Software Installation and Configuration 6.5.4 6 Additional Configuration Information This documentation provides only minimal required configuration information. For complete information about available configuration options, please refer to documentation provided with your NTP distribution.
6 6.6 NTP Software Installation and Configuration Windows NT Installation The following instructions are specific to installing the port of NTP for Windows NT distributed by Trimble Navigation at ftp://ftp.timble.com/pub/ntp/binaries/winnt. ! Note – To install NTP, you must log into the Windows NT system as a user with administrator privileges. ! Note – Other third-party distributions of NTP for Windows NT may not support the Acutime NTP reference clock.
NTP Software Installation and Configuration 6.6.1 6 Automatic Installation The automatic installation program for Windows NT performs all the steps required to install and configure the Network Time Protocol Service for Windows NT, with minimal input from the user. For detailed installation instructions, please refer to the documentation accompanying the NTP installation program.
6 NTP Software Installation and Configuration 6.6.2 Manual Installation Manual installation requires the user to create the configuration file, copy the NTP executable to the appropriate location on disk, and then install, configure and start the NTP service. The manual installation procedures for the NTP software are below. Create the Configuration File The NTP configuration file, NTP.CONF, should be created in the \WINNT\ directory. The lines preceded by # symbols are comments and are ignored by NTP.
NTP Software Installation and Configuration ! 6-18 3. Add SERVER lines for available NTP servers on your network. You must add one line for each NTP server with which you want your time server to communicate. 4. NTP clients should not be included in the SERVER configuration entries in the configuration file. 6 Note – If you are using NOTEPAD to create the configuration file, make sure that you select All files in the Save as type drop-down menu (this avoids creating a file named NTP.CONF.
6 NTP Software Installation and Configuration Copying Executable Files The NTP service requires the NTP service executable, NTPD.EXE, to be available at system boot. In this example, the NTP executable is located in the \WINNT\SYSTEM32 directory. 1. Verify that all required files are present. The file sizes and dates may vary, but all files must be present for successful installation.
NTP Software Installation and Configuration 2. 6 Copy NTPQ.EXE, NTPDATE.EXE, NTPDC.EXE, NTPTRACE.EXE and NTPD.EXE to the \WINNT\SYSTEM32 directory. This operation ensures the NTP service files are available to Windows NT when the system starts.
6 NTP Software Installation and Configuration Installing the Service The NTP service must be registered with the Windows NT Service Control Manager and configured to start at system boot. To register the service, use the command line utility, INSTSRV.EXE, provided with NTP. The INSTSRV.EXE utility requires a single parameter representing the complete path to the location of the NTPD.EXE executable. This example assumes Windows NT is installed in: C:\WINNT.
NTP Software Installation and Configuration ! 6 Note – Make sure to also type the .exe extension of the file name. The program has registered the NTP service with the operating system. A message is printed informing the user to change the account name and password for NTP. This is not necessary in later versions of the Windows NT port.
6 NTP Software Installation and Configuration 6.6.3 Starting the Service The last steps are performed using the Services Applet in the Windows NT Control panel. 1. Open the Control Panel Services Applet. 2. Scroll to Network Time Protocol. 3. Make sure Startup is set to Automatic. 4. Click Start. NTP starts and the Network Time Protocol service status changes to Started. Close the Services Applet. Manual NTP configuration is complete. NTP will start each time the system is booted.
NTP Software Installation and Configuration 6.7 6 UNIX Installation Unix installation must be performed by a user with root (or super-user) privileges on the system. The host system is usually configured to start NTP when the system boots, so that re-synchronization can be established quickly in case of a power or network failure. Consult your UNIX system documentation to determine what start-up scripts must be modified to load NTP at system boot time.
6 NTP Software Installation and Configuration 6.7.1 Create the Configuration File The NTP configuration file, NTP.CONF, should be located in the /ETC directory. The window below shows a simple configuration file declaring a Acutime NTP reference clock and a network time server in the Trimble.COM domain. The Acutime NTP reference clock is declared as unit #1. A maximum of four Acutime NTP reference clocks can be connected to any UNIX host. Valid unit numbers on UNIX systems are 0–3.
NTP Software Installation and Configuration 6.7.2 6 Set Up Device Links NTP attempts to open the I/O file /DEV/ACUTIMEX, to communicate with the Acutime NTP reference clock. The x represents the unit number of the reference clock in the configuration file. A symbolic link /DEV/ACUTIMEX must be set up to point to the correct host serial port.
6 NTP Software Installation and Configuration 1. Replace the string ttyb in the ln command with the appropriate serial port designator for your system. 2. Replace the number 1 in the string /dev/Acutime1 with the unit number in your NTP configuration file. Serial port designators on UNIX systems are usually designated by /dev/cuau or /dev/ttyu, where u may be composed of one or more alphanumeric characters.
NTP Software Installation and Configuration 6.7.3 6 Hardware Configuration You may want to use a system configuration tool to enable and configure system serial ports to function with Acutime. Turn off any login service or modem server that may be attempting to use the port. Figure 6-3 Disabling Serial Port Services Using an Administrative Tool Acutime NTP uses the following serial port configuration: • 9600 baud, 8-bits, 1-stop bit, odd parity. • No DSR signal is generated.
6 NTP Software Installation and Configuration 6.7.4 Copying Executable Files If you obtained binary executable versions of the NTP daemon and its utilities, you will have to unpack the archive and manually move the files to the desired storage directory. NTP is commonly located in /USR/LOCAL/BIN. You must also edit your startup scripts to point to the location of the NTP executable you choose.
NTP Software Installation and Configuration 6.7.5 6 System Initialization Some systems may require additional initialization before NTP can run. Sun OS and Solaris may require running the TICKADJ utility to turn off synchronization with the onboard real-time clock.
6 NTP Software Installation and Configuration 6.7.6 Start NTP Execute NTP from the command line by typing the path and name of the ntp executable: /usr/local/bin/ntpd Installation of NTP is complete. You still need to modify startup scripts to ensure NTP is loaded when the system reboots. To verify the correct operation of NTP and the Acutime NTP reference clock, follow the instructions in the next section, Monitoring NTP.
NTP Software Installation and Configuration 6.8.1 6 NTP Events on Windows NT On Windows NT, the Application Event Log is used to record NTP events. Event Log Entries Check the Application Event Log for status messages from the NTP task. Event log entries generated by the NTP service appear in the event log as shown. When reviewing events in the event log, begin with the first event, and move upwards reviewing events in chronological order.
6 NTP Software Installation and Configuration The first entry in the Application log is the NTP startup message, reporting the NTP Version and build date. This entry indicates that NTP has started. For more information on system log entries generated by NTP, see Appendix E, NTP Diagnostics and Debugging.
NTP Software Installation and Configuration 6.8.2 6 UNIX System Log Files In its native UNIX environment, NTP uses the host system’s system log facilities to send reports to the operating system log files. Refer to your specific system’s documentation to learn how to check the system log reports. Monitor the host’s system message log for status messages from the NTP task.
6 NTP Software Installation and Configuration 6.8.3 NTPQ – The NTP Query Utility NTP includes a network-enabled monitoring utility called NTP QUERY. This utility has a number of features that enable the user to monitor the performance of all time servers from a single console. To learn more about NTPQ, please refer to NTP documentation.
NTP Software Installation and Configuration 6 NTP is Communicating with the Acutime NTP Reference Clock The Acutime NTP reference clock is identified in the list as GPS_ACUTIME. The data indicates that the Acutime GPS is selected as reference clock, that it was last polled 61 seconds ago, and that it has responded to each of the last 11 polls. The offset between the system clock and UTC is 17 microseconds, with a jitter of 2 microseconds. The use of the rv command is also shown above.
6 NTP Software Installation and Configuration NTP is not Running If NTP is not running on the machine, you will see a timeout message: ntpq> pe hostname.trimble.com: timed out, nothing received ***Request timed out ntpq> Problems with NTP and the Acutime NTP reference clock can be observed using NTPQ by monitoring the when and reach fields of the GPS_ACUTIME line item.
NTP Software Installation and Configuration 6 The reach count for GPS_ACUTIME is 0, which indicates a clock or communication failure. Observe also that the status reports sync_ntp, and that refid is no longer GPS, indicating the server has fallen back to an available network time source. For more information on correcting this condition, see Appendix E.
A Trimble Standard Interface Protocol The Trimble Standard Interface Protocol (TSIP) provides commands that the system designer can use to configure a GPS receiver for optimum performance in a variety of applications. TSIP enables the system designer to customize the configuration of a GPS module to meet the requirements of a specific application. TSIP is a simple bidirectional, binary packet protocol used in a wide variety of Trimble GPS receivers.
A Trimble Standard Interface Protocol meaning and format of the data that follows. Each packet begins and ends with control characters. A.1.1 Packet Structure TSIP packet structure is the same for both commands and reports.The packet format is: is the byte 0x10, is the byte 0x03, and is apacket identifier byte, which can have any value except for and . The bytes in the data string can have any value.
A Trimble Standard Interface Protocol DOUBLE (8 byte REAL) is sent as a series of eight bytes (a, b, c, d, e, f, g, h); it has a precision of 52 significant bits, a little better than 15 digits. The TSIP protocol is the primary protocol used by the Ace UTC and Acutime 2000 receivers. This document describes in detail all TSIP packet identification codes, the format of each packet, and all available information that can be output from the Ace UTC and Acutime 2000.
A Trimble Standard Interface Protocol A.2.1 Nomenclature Historically, the ports of the Smart Antenna product lines which include Acutis, Acutime and Palisade products, have been described using letters "A" and "B". The board-level products, such as Lassen, Ace and Core Module 3, have historically used port numbers "1" and "2" to label the ports on the starter kit. The Acutime 2000 ports are referenced by letters "A" and "B", conformant to standards established by the Palisade product line.
A Trimble Standard Interface Protocol For systems with minimal bandwidth for processing serial data streams, the receivers can be configured as silent devices, which only generate I/O when polled. On the other end of the spectrum, the Ace UTC and Acutime 2000 receivers can be configured to output various automatic report packets and protocols to satisfy demanding real-time update requirements of complex monitoring systems.
A Trimble Standard Interface Protocol Secondary Port Features (Ace UTC) Due to the number of available I/O pins, the Ace UTC does not generate output on its secondary port. The input port may be configured as shown in the table below. Table A-4 A.2.3 Secondary Port Features (Ace UTC) Port Designator Input Default Output “Port 2” TSIP, RTCM TSIP N/A Event Input The Ace UTC and Acutime 2000 receivers are capable of timestamping external events with high-precision.
A Trimble Standard Interface Protocol operating condition of the receiver. Messages are output in the following order. Upon output of packet 82, the sequence is complete and the receiver is ready to accept commands. Table A-6 Packets Output at Power-Up Output ID Description 46 Receiver health 4B Machine code/status 45 Software version 83 Double precision XYZ position If single precision is selected, packet 42 is output instead.
A Trimble Standard Interface Protocol A.5 Default Background Packets for Acutime 2000 The Acutime 2000 automatically outputs a set of packets that you can monitor for changes in receiver operations, including receiver health, time, almanac pages, and ephemeris updates. These messages are output at the rates indicated in the table below.
A A.6 Trimble Standard Interface Protocol Default Automatic Position and Velocity Reports for Acutime 2000 The Acutime 2000 automatically outputs position and velocity reports at set intervals. Report intervals are controlled by packet 35. Table A-9 ! A.
A Trimble Standard Interface Protocol A.8 Low-Latency Timing Packets The Ace UTC and Acutime 2000 feature a sequence of high-priority timing super packets, which are output within a bounded period of time after the PPS. The LLT packets offer an advanced data interface for applications requiring accurate data reports in a time constrained environment. On Acutime 2000 and Ace UTC, the first super packet will start transmission no later than 15 – 25 ms after the PPS transition.
A A.9 Trimble Standard Interface Protocol Event Packets Event packets 8F-0B and 8F-0A are output in response to the event input as configrured by packet 8E-A5 A.10 Satellite Data Packets The following packets request data transmitted by the GPS satellites and satellite tracking information.
A Trimble Standard Interface Protocol A.11 Customizing Receiver Operations The following packets let you customize the receiver output for your application.
A Trimble Standard Interface Protocol The following packets let you customize receiver operations.
A Trimble Standard Interface Protocol A.12 Command Packets Sent to the Receiver Table A-14 summarizes the command packets sent to the receiver. It includes a short description of each packet and the associated output packet. In some cases, the response packets depend on user-selected options. These selections are described beginning on page A-20.
A Table A-14 Trimble Standard Interface Protocol Command Packets Sent to the Receiver (Continued) Input Packet Description Output ID 38 Load satellite system data 58 39 Satellite enable/disable and health heed/ignore 59 (Note 3) 3A Last raw measurement 5A 3B Satellite ephemeris status 5B 3C Tracking status 5C 3D Timing port configuration 3D 3F-11 Request EEPROM segment status 5F-11 7A Set/request NMEA interval and message mask 7B BB Set receiver configuration BB BC Set port
A Trimble Standard Interface Protocol Table A-14 Input Command Packets Sent to the Receiver (Continued) Packet Description Output ID Note 2: Entering 1SV mode initiates automatic output of packet 54. Note 3: Not all packet 39 operations have a response. See packet 39 description. Note 4: Output is determined by packet 35 settings. A.13 Report Packets Sent by the GPS Receiver to the User Table A-15 summarizes the packets output by the receiver.
A Table A-15 Trimble Standard Interface Protocol Report Packets Sent by GPS Receiver to User (Continued) Output ID Packet Description Input 54 One-satellite bias and bias rate 22 55 I/O options 35 56 Velocity fix (ENU) 37 57 Information about last computed fix 37 58 GPS system data/acknowledge 38 59 Satellite enable/disable and health heed/ignore 39 5A Raw measurement data 3A 5B Satellite ephemeris status 3B 5C Satellite tracking status 3C 5F-11 Request EEPROM segment statu
A Trimble Standard Interface Protocol Table A-15 Output ID Report Packets Sent by GPS Receiver to User (Continued) Packet Description Input 8F-A6 Response to self-survey command 8E-A6 8F-AB Primary timing packet 8E-AB 8F-AC Supplemental timing packet 8E-AC 8F-AD UTC event time Event/Auto A-18 Acutime 2000 Synchronization Kit User Guide
A A.14 Trimble Standard Interface Protocol Packet Structure TSIP packet structure is the same for both commands and reports. The packet format is: is the byte 0x10, is the byte 0x03, and is a packet identifier byte, which can have any value except for and . The bytes in the data string can have any value.
A Trimble Standard Interface Protocol A.15 Packet Descriptions Command packets are sent from an external device, such as a computer or terminal, to the receiver when requesting report packets, setting receiver parameters, or performing receiver command operations such as resetting the receiver. Many command packets have a corresponding report packet, which is sent to the external device in response to the command packet. Some commands perform discrete operations and have no matching report packet.
A Trimble Standard Interface Protocol 0x1E Command Packet 1E Initiate Cold or Factory Reset This command packet tells the receiver to perform either a cold reset or a factory reset. A cold reset clears all navigation data (for example, almanac, and ephemeris) stored in RAM and is equivalent to a power cycle. A factory reset also restores the factory defaults for all configuration and navigation parameters stored in non-volatile memory.
A Trimble Standard Interface Protocol 0x20 Command Packet 20 Almanac Request This packet requests almanac data for one satellite from the GPS receiver. This packet contains one data byte specifying the satellite PRN number. The GPS receiver returns packet 40 hex. 0x21 Command Packet 21 Current Time Request This packet requests current GPS time. This packet contains no data. The GPS receiver returns packet 41 hex.
A Trimble Standard Interface Protocol Table A-19 0x24 Command Packet 23 Byte Item Type Units 4-7 Y Single meters 8-11 Z Single meters Command Packet 24 GPS Receiver Position Fix Mode Request This packet requests the current position fix mode of the GPS receiver. This packet contains no data. The GPS receiver returns packet 6D. 0x25 Command Packet 25 Initiate Soft Reset / Self Test Command This packet commands the GPS receiver to perform a software reset.
A Trimble Standard Interface Protocol 0x27 Command Packet 27 Signal Levels Request This packet requests signal levels for all satellites currently being tracked. This packet contains no data. The GPS receiver returns packet 47. 0x28 Command Packet 28 GPS System Message Request This packet requests the GPS system ASCII message sent with the navigation data by each satellite. This packet contains no data. The GPS receiver returns packet 48.
A Trimble Standard Interface Protocol To use the fixed altitude survey mode, the receiver must be configured to Manual 2-D navigation mode using packet BB. The reference altitude will be used in 2-D survey from both warm and cold starts. ! Note – If the receiver altitude is set above 18,000 m, the receiver will be forced to reset each time it acquires satellites. This is implemented to conform with the COCOM industry standard.
A Trimble Standard Interface Protocol 0x2B Command Packet 2B Initial Position (Latitude, Longitude, Altitude) Command This packet provides the GPS receiver with an approximate initial position in latitude and longitude coordinates (WGS-84). This packet is useful if the user has moved more than about 1,000 miles since the previous fix. ! Note – The GPS receiver can initialize itself without any data from the user; this packet merely reduces the time required for initialization.
A 0x2E Trimble Standard Interface Protocol Command Packet 2E GPS Time Command This packet provides the approximate GPS time of week and the week number to the GPS receiver. The GPS receiver returns packet 4E. The data format is shown below. The GPS week number reference is Week # 0 starting January 6, 1980. The seconds count begins at the midnight which begins each Sunday morning.
Trimble Standard Interface Protocol A Inputting accurate position sets the self-survey completion state to 100%. The uploaded position is not stored in EEPROM unless it is stored with command packet 8E-26. The input position is reported by packet 8F-AC.
A 0x32 Trimble Standard Interface Protocol Command Packet 32 Accurate Initial Position (Latitude, Longitude, Altitude) Command This packet is identical in content to packet 2B. This packet provides the GPS receiver with an initial position in latitude, longitude, and altitude coordinates. However, the GPS receiver assumes the position provided in this packet to be accurate.
A Trimble Standard Interface Protocol 0x35 Command Packet 35 I/O Option Flags Command This packet requests the current I/O option states and optionally allows the I/O option states to be set as desired. To request the option states without changing them, the user sends the packet with no data bytes included. To change any option states, the user includes 4 data bytes with the values indicated below in the packet.
A Trimble Standard Interface Protocol Table A-22 Command Packet 35 Byte Parameter Name Bit Position Default Bit Value Option Associated Packets 0 Position 0 (LSB) 0 XYZ ECEF Output 0: Off, 1: On 42 or 83 1 1 LLA Output 0: Off, 1: On 4A or 84 2 0 LLA ALT Output 0: HAE (current datum) 1: MSL geoid WGS-84 4A or 84 3 0 ALT input 0: HAE (current datum) 1: MSL geoid WGS-84 2A 4 1 Precision-of-position output 0: Single-precision packet 42 and/or 4A.
A Trimble Standard Interface Protocol Table A-22 Command Packet 35 (Continued) Byte Parameter Name Bit Position Default Bit Value Option Associated Packets 2 Timing 3 0 Synchronized measurements 0: Off 1: On N/A 4 0 Minimize Projection 0: Off, 1: On N/A 3 Auxiliary 5-7 0 Unused 0 0 Raw measurements 0: Off, 1: oN 5A 1 1 Doppler smoothed codephase 0: Raw, 1: Smoothed 5A 2-7 Unused Packet 35 is used to control the format and timing of the position and velocity output.
A Trimble Standard Interface Protocol Alternatively, in the integer second mode, the most recent measurements are projected to next integer second, and the solution is then valid at this time. The benefit of this mode is the standard fix time and a 1 Hz output rate. The drawbacks are that some measurement projection is performed and that the fix may be slightly older than with the default option. This mode also conforms to the output rate of NMEA.
A Trimble Standard Interface Protocol • Minimized Projection - This bit controls the time of the position fix relative to the time of the satellite range measurements. The default mode is OFF. In this mode, the time of solution is the time at which the GPS position fix is computed. Thus, all measurements are projected by an interval which is roughly the amount of time it takes to compute the solution.
A 0x37 Trimble Standard Interface Protocol Command Packet 37 Last Position and Velocity Request This packet requests information regarding the last position fix. The GPS receiver returns packet 57 and the appropriate position packet 42 or 4A, or 83 or 84, and the appropriate velocity packet 43 or 56, based on the I/O options in effect. In timing mode, the GPS receiver returns packets 57 and 54.
A Trimble Standard Interface Protocol Table A-23 Command Packet 38 Byte Item Type Value Meaning 0 Operation Byte 1 2 Request data from receiver Load data into receiver 1 Type of data Byte 1 2 3 4 5 6 Not used Almanac Health page, T_oa, WN_oa Ionosphere UTC Ephemeris 2 Sat PRN# Byte 0 1-32 Data that is not satellite-ID specific satellite PRN number 3 length (n) Byte 4 to n+3 data A-36 Number of bytes of data to be loaded n Bytes Acutime 2000 Synchronization Kit User Guide
A 0x39 Trimble Standard Interface Protocol Command Packet 39 Satellite Attribute Database Command Normally the GPS receiver selects only healthy satellites (based on transmitted values in the ephemeris and almanac) that satisfy all mask values for use in the position solution. This packet allows you to override the internal logic and force the receiver to either unconditionally disable a particular satellite or to ignore a bad health flag.
A Trimble Standard Interface Protocol 0x3A Command Packet 3A Last Raw Measurement Request This packet requests the most recent raw measurement data for one specified satellite. The GPS receiver returns packet 5A if data is available.
A 0x3C Trimble Standard Interface Protocol Command Packet 3C Satellite Tracking Status Request This packet requests the current satellite tracking status. The GPS receiver returns packet 5C if data is available.
A Trimble Standard Interface Protocol 0x3D Command Packet 3D Timing Port Configuration Command This packet is superceded by 0xBC. 0x3F-11Command Packet 3F-11 EEPROM Segment Commands This command packet requests the status of the EEPROM segments and clears the EEPROM status minor alarm bit (Bit 10) in the supplemental timing packet 8F-AC. The ACE UTC replies with report packet 5F-11.
A Table A-29 Trimble Standard Interface Protocol Report Packet 40 Byte Item Type Units 23-26 square_root_A SINGLE (meters) 27-30 OMEGA_0 SINGLE radians 31-34 omega SINGLE radians 35-38 M_0 SINGLE radians 1/2 T_zc is normally positive. If no almanac data is available for this satellite, then T_zc is negative. T_zc and the week number in this packet refer to the Z-count time and week number at the time the almanac was received. The remaining items are described in the ICD-GPS-200.
A Trimble Standard Interface Protocol " Caution – GPS week numbers run from 0 to 1023 and then cycles back to week #0. Week #0 began January 6, 1980. Another week #0 began August 22, 1999. The receiver automatically adds 1024 to the GPS week number after August 21, 1999, and reports the cumulative week number. The seconds count begins with "0" each Sunday morning at midnight GPS time.
A 0x42 Trimble Standard Interface Protocol Report Packet 42 Single-Precision Position Fix, XYZ ECEF Report This packet provides current GPS position fix in XYZ ECEF coordinates. If the I/O "position" option is set to "XYZ ECEF" and the I/O "precision-of-position output" (Packet 35) is set to singleprecision, and the packet is masked for output by packet 8E-4D, then the GPS receiver sends this packet each time a fix is computed. The data format is shown below.
A Trimble Standard Interface Protocol 0x43 Report Packet 43 Velocity Fix, XYZ ECEF Report This packet provides current GPS velocity fix in XYZ ECEF coordinates. If the I/O "velocity" option (Packet 35) is set to "XYZ ECEF ", and the packet is masked for output by packet 8E-4D, then the GPS receiver sends this packet each time a fix is computed if selected by the I/O "timing" option. The data format is shown below.
A 0x45 Trimble Standard Interface Protocol Report Packet 45 Software Version Information Report This packet provides information about the version of software in the Navigation and Signal Processors. The GPS receiver sends this packet after power-on and in response to packet 1F.
A Trimble Standard Interface Protocol 0x46 Report Packet 46 Health of Receiver Report This packet provides information about the satellite tracking status and the operational health of the receiver. The receiver sends this packet after power-on or software-initiated resets, in response to packet 26, during an update cycle, when a new satellite selection is attempted, and when the receiver detects a change in its health. Packet 4B is always sent with this packet.
A Trimble Standard Interface Protocol The error codes in Byte 1 of packet 46 are encoded into individual bits within the byte. The bit positions and their meanings are shown in Table A-36.
A Trimble Standard Interface Protocol 0x47 Report Packet 47 Signal Levels for all Satellites Report This packet provides received signal levels for all satellites currently being tracked or on which tracking is being attempted (that is, above the elevation mask and healthy according to the almanac). The receiver sends this packet only in response to packet 27. Table A-37 shows the data format.
A 0x49 Trimble Standard Interface Protocol Report Packet 49 Almanac Health Page Report This packet provides health information on all 32 satellites. Packet data consists of 32 bytes each containing the 6-bit health from almanac page 25. The first byte is for satellite #1, and so on. The receiver sends this packet in response to packet 29 and when this data is received from a satellite.
A Trimble Standard Interface Protocol The Single-Precision LLA Position Fix variation of the packet provides current GPS position fix in LLA (latitude, longitude, and altitude) coordinates. If the I/O "position" option is set to "LLA" and the I/O "precision-of-position output" is set to single-precision, and the packet is masked with packet 8E-4D, then the receiver sends this packet each time a fix is computed. The data format is shown below.
A 0x4B Trimble Standard Interface Protocol Report Packet 4B Machine/Code ID and Additional Status Report The receiver transmits this packet in response to packets 25 and 26 and following a change in state. This packet identifies the receiver and may present error messages. Packet 46 is always sent with this packet. The machine ID can be used by equipment communicating with the receiver to determine the type of receiver to which the equipment is connected.
A Trimble Standard Interface Protocol 0x4C Report Packet 4C Operating Parameters Report This packet provides several operating parameter values of the receiver. The receiver sends this packet in response to packet 2C. The data string is four SINGLE values. The dynamics code indicates the expected vehicle dynamics and is used to assist the initial solution. The elevation angle mask determines the lowest angle at which the receiver tries to track a satellite.
A 0x4D Trimble Standard Interface Protocol Report Packet 4D Oscillator Offset This packet provides the current value of the receiver master oscillator offset in Hertz at carrier. This packet contains one SINGLE number (4 Bytes). The receiver sends this packet in response to packet 2D. 0x4E Report Packet 4E GPS Time Change Acknowledgment Indicates whether the receiver accepted the time given in a Set GPS time packet. The receiver sends this packet in response to packet 2E.
A Trimble Standard Interface Protocol 0x4F Report Packet 4F UTC Parameters Report This packet is sent in response to command packet 2F and contains 26 bytes. It reports the UTC information broadcast by the GPS system. For details on the meanings of the following parameters, consult ICD200, Sections 20.3.3.5.2.4, 20.3.3.5.1.8, and Table 20-IX. On the simplest level, to get UTC time from GPS time, subtract ∆TLS seconds.
A 0x54 Trimble Standard Interface Protocol Report Packet 54 Bias and Bias Rate Report The receiver sends this packet to provide the computed clock-only solution when the receiver is in the manual or automatic Overdetermined Clock mode or Time Only (1-SV) mode. Table A-46 Report Packet 54 Byte Item Type Units 0-3 Bias SINGLE meters 4-7 Bias rate SINGLE meters/second 8-11 Time of fix SINGLE seconds The bias is the offset of the receiver internal time clock from GPS time.
A Trimble Standard Interface Protocol 0x56 Report Packet 56 Velocity Fix, East-North-Up (ENU) Report If East-North-Up (ENU) coordinates have been selected for the I/O "velocity" option (Packet 35), the receiver sends this packet under the following conditions: (1) each time that a fix is computed if masked for output by packet 8E-4D; (2) in response to packet 37 (last known fix). The data format is shown in Table A-47.
A Trimble Standard Interface Protocol 0x57 Report Packet 57 Information About Last Computed Fix Report This packet provides information concerning the time and origin of the previous position fix. The receiver sends this packet, among others, in response to packet 37. The data format is shown below.
A Trimble Standard Interface Protocol 0x58 Report Packet 58 Satellite System Data/Acknowledge from Receiver This packet provides GPS data (almanac, ephemeris, etc.). The receiver sends this packet under the following conditions: (1) on request; (2) in response to packet 38 (acknowledges the loading of data). The data format is shown below.
A Trimble Standard Interface Protocol Table A-50 Report Packet 58 – ALMANAC Data Report Byte Item Type Meaning 4 t_oa_raw BYTE (cf. ICD-200, Sec 20.3.3.5.1.2) 5 SV_HEALTH BYTE (cf. ICD-200, Sec 20.3.3.5.1.2) 6-9 e SINGLE (cf. ICD-200, Sec 20.3.3.5.1.2) 10-13 t_oa SINGLE (cf. ICD-200, Sec 20.3.3.5.1.2) 14-17 i_o SINGLE (cf. ICD-200, Sec 20.3.3.5.1.2) 18-21 OMEGADOT SINGLE (cf. ICD-200, Sec 20.3.3.5.1.2) 22-25 sqrt_A SINGLE (cf. ICD-200, Sec 20.3.3.5.1.
A Trimble Standard Interface Protocol Table A-51 Report Packet 58 – ALMANAC HEALTH Data Report Byte Item Type Meaning 4 week # for health BYTE (cf. ICD-200, Sec 20.3.3.5.1.3) 5-36 SV_health 32 BYTES (cf. ICD-200, Sec 20.3.3.5.1.3) 37 t_oa for health BYTE (cf. ICD-200, Sec 20.3.3.5.1.
A Trimble Standard Interface Protocol Table A-53 Report Packet 58 – UTC Data Report Byte Item Type Meaning 4-16 --- --- compact storage of the following info 17-24 A_0 DOUBLE (cf. ICD-200, Sec 20.3.3.5.1.8) 25-28 A_1 SINGLE (cf. ICD-200, Sec 20.3.3.5.1.8) 29-30 delta_t_LS INTEGER (cf. ICD-200, Sec 20.3.3.5.1.8) 31-34 t_ot SINGLE (cf. ICD-200, Sec 20.3.3.5.1.8) 35-36 WN t INTEGER (cf. ICD-200, Sec 20.3.3.5.1.8) 37-38 WN_LSF INTEGER (cf. ICD-200, Sec 20.3.3.5.1.
A Trimble Standard Interface Protocol Table A-54 Report Packet 58 – EPHEMERIS Data Report (Continued) Byte Item Type Meaning 41 IODE BYTE (cf. ICD-200, Sec 20.3.3.4) 42 fit_interval BYTE (cf. ICD-200, Sec 20.3.3.4) 43-46 C_rs SINGLE (cf. ICD-200, Sec 20.3.3.4) 47-50 delta_n SINGLE (cf. ICD-200, Sec 20.3.3.4) 51-58 M_0 DOUBLE (cf. ICD-200, Sec 20.3.3.4) 59-62 C_uc SINGLE (cf. ICD-200, Sec 20.3.3.4) 63-70 e DOUBLE (cf. ICD-200, Sec 20.3.3.4) 71-74 C_us SINGLE (cf.
A 0x59 Trimble Standard Interface Protocol Report Packet 59 Satellite Attributes Database Report This packet is returned in response to packet 39 if operation mode 3 or 6 is used with packet 39. Normally the GPS receiver selects only healthy satellites (based on transmitted values in the ephemeris and almanac) which satisfy all mask values, for use in the position solution.
A Trimble Standard Interface Protocol 0x5A Report Packet 5A Raw Measurement Data Report This packet provides raw GPS measurement data. If the I/O auxiliary option for "raw data" has been selected (packet 35), and it is masked for output by packet 8E-4D, the receiver outputs a packet 5A for each satellite being tracked, once per second. The receiver also sends this packet in response to packet 3A. The data format is shown below.
A Trimble Standard Interface Protocol Signal level The Signal Level (Byte 5) is a linear approximation of C/N0 which is stated in antenna amplitude measurement units (AMUs), a Trimble devised unit. Note – SNR (±3) = 20log((signal counts/noise counts)*(BW/2)) where: signal counts = 64 * AMU; noise counts = 90, and BW = 1000Hz.
A Trimble Standard Interface Protocol Time of measurement The time of measurement (Byte 17) is the center of the sample interval adjusted by adding the receiver-supplied codephase (modulo mS) to a user-determined integer number of mS between user and satellite. The receiver codephase resolution is 1/16th of a C/A code chip. This corresponds to: 1/16 × C/A code chip ≈ 977.517ns/16 ≈ 61.0948 ns ≈ 61.0948 × speed of light, m/s ≈ 18.
A Trimble Standard Interface Protocol on the status of the ephemeris in the receiver for a given satellite. The structure of packet 5B is shown in the table below. Table A-57 Report Packet 5B Byte Item Type 0 Satellite PRN number BYTE 1-4 Time of Collection SINGLE 5 Health BYTE 6 IODE BYTE 7-10 toe SINGLE 11 Fit Interval Flag BYTE 12-15 SV Accuracy (URA) SINGLE Units seconds seconds meters SV PRN Number is from 1 to 32 representing the satellite PRN number.
A Trimble Standard Interface Protocol 0x5C Report Packet 5C Satellite Tracking Status Report This packet provides tracking status data for a specified satellite. Some of the information is very implementation-dependent and is provided mainly for diagnostic purposes. The receiver sends this packet in response to packet 3C hex. The data format is shown below.
A Table A-58 Trimble Standard Interface Protocol Report Packet 5C (Continued) Byte/Item Type/Units Value/Meaning Byte 12-15 / Elevation SINGLE/ radians Approximate elevation of this satellite above the horizon. Updated about every 15 seconds. Used for searching and computing measurement correction factors. Byte 16-19 / Azimuth SINGLE/ radians Approximate azimuth from true north to this satellite. Updated about every 15 seconds. Used for computing measurement correction factors.
A Trimble Standard Interface Protocol 0x5F-11 Report Packet 5F-11 EEPROM Segment Status Reports This report packet is sent in response to command packet 3F-11. It contains all the segments in the EEPROM. The Segment Status is bitwise encoded with the status of each segment and is cleared to 0 after it is read. A zero in the bit field indicates that the segment contents are valid.
A Trimble Standard Interface Protocol 0x60 Command Packet 0x60 Type 1 Differential GPS Corrections This packet provides the ACE UTC GPS with differential corrections from RTCM SC-104 record types 1 and 9, in the TSIP format. There is no response to this packet. If bit 6 is set, the corrections are as in RTCM Type 9 records. The format for this packet is shown in Table A-60. Table A-60 Byte Bit Report Packet 0x60 Data Formats Item Type Range Units 0-1 Modified z-count UINT16 0-5999 .
A Trimble Standard Interface Protocol The next 5 bytes are repeated as a group for each satellite. The SV PRN and scale factor contains the SV PRN in the lower 5 bits, and the scale factor in the upper 3 bits. Range corrections are scaled by 0.02 meters times 2 raised to the scale factor power. Range-rate corrections are scaled by 0.002 meters per second times 2 raised to the scale factor power. The format is shown in Table A-61.
A Trimble Standard Interface Protocol 0x61 Command Packet 0x61 Set Differential GPS Corrections This TSIP packet provides the delta differential corrections from RTCM-104 record type 2. There is no response to this packet. Scale factors are version 1 unless the version 2 flag is set. The format for this packet is shown in Table A-62. Table A-62 Byte Command Packet 0x61 Data Formats Bit 0-1 Item Type Value Definition Modified Z-count UINT16 0-5999 .
A Trimble Standard Interface Protocol 0x6D Report Packet 6D All-In-View Satellite Selection Report This packet provides a list of satellites used for position fixes by the GPS receiver. The packet also provides the PDOP, HDOP, and VDOP of that set and provides the current mode (automatic or manual, 3-D or 2-D). This packet has variable length equal to 16+nsvs (minimum 4), where "nsvs" is the number of satellites used in the solution.
A Trimble Standard Interface Protocol 0x7A Command Packet 7A Set or Request NMEA Interval and Message Mask The NMEA mask determines whether or not a given NMEA message will be output. If the bit for a message is set, the message will be sent every “interval” seconds. To determine the NMEA interval and message mask, use the values shown in Table A-64. While fixes are being generated, the output order is: ZDA, GGA, GLL, VTG, GSA, GSV, RMC.
A Trimble Standard Interface Protocol 0x7B Report Packet 7B NMEA Message Output This packet is sent in response to command packet 7A and has the same data format as packet 7A. 0x83 Report Packet 83 Double-precision XYZ Position Fix And Bias Information This packet provides current GPS position fix in XYZ ECEF coordinates. If the I/O "position" option is set to "XYZ ECEF" and the I/O double-precision option is selected (packet 35), the receiver sends this packet each time a fix is computed.
A 0x84 Trimble Standard Interface Protocol Report Packet 84 Double-precision LLA Position Fix and Bias Information This packet provides current GPS position fix in LLA coordinates. If the I/O "position" option is set to "LLA" and the double-precision option is selected (packet 35), the receiver sends this packet each time a fix is computed. The data format is shown in the table below.
A Trimble Standard Interface Protocol 0xBB Command Packet BB Set Primary Receiver Configuration TSIP command packet BB contains the primary receiver configuration parameters. The Ace UTC and Acutime 2000 store 3 independent sets of configuration parameters. These are designated as the "Mobile", "Survey" and "Timing" configurations.
A Trimble Standard Interface Protocol Table A-68 Vaild GPS Configuration Settings Survey State Active Configuration Dynamics Code Operating Dimension Survey Disabled Mobile any any Survey Active Survey Land/Sea/Air 2D or 3D or Auto Survey Complete Timing Stationary 1SV or Over-determined Send packet BB with subcode 0 as the only data byte, to query for the primary receiver configuration. The receiver will respond with report packet BB.
Trimble Standard Interface Protocol A Frequent constellation switching is undesirable because position jumps may be experienced when Selective Availability is present and DGPS is not available to remove these effects. The benefit of a low elevation mask is that more satellites are available for use in a solution and a better PDOP may be yielded. The current default mask is set to 0.1745 radians (10°) and provides a reasonable trade-off between the benefits and drawbacks.
A Trimble Standard Interface Protocol PDOP Mask and Switch The PDOP mask is the maximum PDOP limit for which any 2-D or 3-D position solution will be made. The PDOP switch is the level at which the receiver stops attempting a 3-D solution, and tries for a 2-D solution when in automatic 2-D, 3-D mode. The switch level has no effect on either manual mode.
A Trimble Standard Interface Protocol Table A-69 Command Packet BB (Continued) Byte # Item Type Value Meaning Default 4 Solution Mode BYTE 1 Overdetermined fix Overdetermined fix 5-8 Elevation Mask SINGLE 0-π/2 Lowest satellite elevation for fixes 0.1745 9-12 AMU Mask SINGLE Minimum signal level for fixes 4.
A Trimble Standard Interface Protocol 0xBB Report Packet BB Report Receiver Configuration TSIP report packet BB is used to report the GPS Processing options. For information about the data formats, see command packet BB. 0xBC Command Packet BC Set Port Configuration Parameters TSIP command packet BC is used to set the communication parameters on Port 1 and Port 2. The table below lists the individual fields within the BC packet. Flow control is not supported. Please refer to section A.
A Trimble Standard Interface Protocol Table A-70 Command Packet BC (Continued) Byte # Item Type Value Meaning Default 4 Parity BYTE 0 1 2 None Odd Even Odd 5 # Stop Bits BYTE 0 2 1 bit 2 bits 1 bit 6 reserved BYTE 0-15 0 = none 0 7 Input Protocols BYTE 0 2 8 none TSIP RTCM (Port 2 only) none 8 Output Protocols BYTE 0 2 4 none TSIP NMEA TSIP 9 Reserved BYTE 0 None 0xBC Report Packet BC Request Port Configuration Parameters TSIP packet BC is used to request the c
A A.16 Trimble Standard Interface Protocol Custom OEM Packets Several packets have been added to the core TSIP protocol to provide additional capability for OEM receivers. In OEM packets 8E and their 8F responses, the first data byte is a subcode that indicates the superpacket type. For example, in packet 8E-14, 14 is the subcode that indicates the superpacket type. Therefore, the ID code for OEM packets is 2 bytes long, followed by the data. A.
A Trimble Standard Interface Protocol 0x8E-0B Command Packet 8E-0B Request or Configure Super Packet Output The 8E-0B packet is identical in function to the 8E-AD packet. If the 8E-0B byte sequence is sent with no data, the receiver will return an 8F-0B packet on port 1. The time reported by the 8F-0B packet on port 1 is always the beginning of the current second.
A Trimble Standard Interface Protocol 0x8E-14 Command Packet 8E-14 Set New Datum This packet allows the user to change the default datum from WGS-84 to one of 180 selected datums or to a user-entered custom datum. The datum is a set of 5 parameters which describe an ellipsoid to convert the GPS receiver's internal coordinate system of XYZ ECEF into Latitude, Longitude and Altitude (LLA). This will affect all calculations of LLA in packets 4A and 84 and 8F-AC and 8F-0B.
A Trimble Standard Interface Protocol Alternatively, the unit will accept a 40 byte input packet containing 5 double-precision floating point values representing the ellipse. The first 3 are DX, DY, and DZ, which represent an offset in meters from the ECEF origin for the ellipse. The fourth parameter is the semi-major axis of the ellipse (called the a-axis) and is also in meters. The fifth parameter is the eccentricity of the ellipse and is dimensionless.
A Trimble Standard Interface Protocol 0x8E-20 Command Packet 8E-20 Request Last Fix with Extra Information This packet requests packet 8F-20 or marks it for automatic output. If only the first byte (20) is sent, an 8F-20 report containing the last available fix will be sent immediately. If two bytes are sent, the packet is marked/unmarked for auto report according to the value of the second byte.
A Trimble Standard Interface Protocol 0x8E-42 Command Packet 8E-42 Production Parameters This packet is used to request the production parameters stored in nonvolatile memory. This packet contains only a single byte, the subpacket ID. The receiver returns packet 8F-42.
A Trimble Standard Interface Protocol 0x8E-4A Command Packet 8E-4A Set/Request PPS Characteristics Using this packet, you can query and control the receiver’s PPS characteristics. The receiver responds to a query or control command with packet 8F-4A.
A Trimble Standard Interface Protocol The default setting for byte 3 is positive. Bytes 4 to 11 define the PPS cable delay offset. The default offset is 0, which corresponds to a 100foot (30-meter) cable. These bytes allow the application to adjust the cable delay offset for longer or shorter cable lengths. Use a cable delay of ± 1.25 ns/foot to adjust PPS offset for cable lengths different than 100 feet. For a longer cable, a negative value should be used to advance the PPS.
A Trimble Standard Interface Protocol The bits are numbered in descending order of receipt, starting with bit 31 as the MSB of Byte 1, down to bit 0 as the LSB of Byte 4. A "0" in the bit position disables automatic output of the associated packets; a "1" in the bit position makes the associated packets available for automatic output. Table A-77 describes the packets affected by each bit.
A Trimble Standard Interface Protocol Table A-77 Bit # Command Packet 8E-4D - Packets Affected By Bits Output Packets When Output Meaning Default Default A2K ACE UTC 1 0 1 0 12 1 0 Reserved 13-29 1 0 Reserved 10 11 (Note 1) 6D, 46, 4B, 82 Reserved Constellation Change, New Fix New satellite selection 30 42, 43, 4A, 54, 56, 83, 84, 8F-20, 1 0 New Fix Update Kinetic and Timing information. Output must be enabled using I/O options.
A Trimble Standard Interface Protocol always on or during fixes which you get if you set the driver switch to 3 or 4.
A Trimble Standard Interface Protocol formats, the ACE UTC GPS will broadcast only one of the formats. If more than one of the formats is masked on for broadcast, then the format with the greatest precision of content will be sent and the rest will not.
A Trimble Standard Interface Protocol Table A-80 Byte Bit Item Type Default Description Subcode UINT8 A 2 K A C E 0xA5 0 1 2 3 4 5 6 0x8F-20 Bit field 0x8F-AB 1 0 0 0 0 1 0 0 0 0 0 0 1 1 7 0x8F-AC 0 1 8 0x8F-0B 0 0 9 0x8F-0B 1 0 10 11 12 0x8F-0B 0x8F-0B 0x8F-AD 0 0 1 0 0 0 13 0x8F-AD 1 0 14 15 0x8F-AD 0x8F-AD 0 0 1 0 Enable 0x8F-20 output on Port Reserved Reserved Reserved Reserved Enable auto TSIP outputs 0x8F-AB, Primary timing info on all TSIP output ports 0x8F-
A Trimble Standard Interface Protocol 0x8E-A6 Command Packet 8E-A6 Issue Self-Survey Command This command packet starts a self-survey. The ACE UTC GPS responds with report packet 8F-A6. This command has no effect when survey is disabled.
A Trimble Standard Interface Protocol 1: Automatically save the surveyed position when the selfsurvey is complete. Self-Survey Length: Use this field to specify the number of position fixes that are to be averaged together to form the self-surveyed position used for clock-only fixes. 31 Limits: 1 to (2 - 1) fixes. ! Note – After disabling the self-survey, the survey in progress can be stopped by issuing a restart self-survey command (0x8E-A6).
A Trimble Standard Interface Protocol 0x8E-AB Command Packet 8E-AB Request Primary Timing Packet This command packet may be used to request the primary timing packet 8F-AB. To receive report packet 8F-AB once per second use command 8E-A5 to enable the automatic output. The Request Type item determines how the ACE UTC GPS will reply to this command. Table A-83 • Request Type 0: The most current primary timing values will be sent in report packet 8F-AB immediately.
A Trimble Standard Interface Protocol 0x8E-AC Command Packet 8E-AC Request Supplemental Timing Packet This command packet can be used to request the supplemental timing packet 8F-AC. To receive report packet 8F-AC once per second use command 8E-A5 to enable the automatic output. The Request Type item determines how the ACE UTC GPS will reply to this command. Table A-84 • Request Type 0: The most current supplemental timing values will be sent in report packet 8F-AC immediately.
A Trimble Standard Interface Protocol 0x8E-AD Command Packet 8E-AD (Acutime 2000 only) Request or Configure Super Packet Output If the 8E-AD byte sequence is sent with no data, the receiver will generate an 8F-AD packet on port 1. The time reported by the 8F-AD packet on port 1 is always the beginning of the current second.
A Trimble Standard Interface Protocol 0x8F-0B Report Packet 8F-0B Comprehensive Time The output of the packet is synchronized with the PPS, and may also be generated in response to external events. Report packet 8F-0B provides easy identification of each timing pulse and contains all the information required for most timing and synchronization applications. Output of this packet can be disabled and configured using the 8E-A5 packet on Port 1.
A Trimble Standard Interface Protocol Table A-85 Report Packet 8F-0B (Continued) Byte # Item Type Meaning 38-41 Oscillator Drift Uncertainty SINGLE Oscillator bias rate uncertainty (meters/second) 42-49 Latitude DOUBLE Latitude in radians 50-57 Longitude DOUBLE Longitude in radians 58-65 Altitude DOUBLE Altitude according to current datum, meters 66-73 Satellite ID 8 BYTES Identification numbers of tracking and usable satellites Bytes 66 through 73 identify the tracking and usabl
A Trimble Standard Interface Protocol 0x8F-14 Report Packet 8F-14 Current Datum Values This packet contains 43 data bytes with the values for the datum currently in use and is sent in response to packet 8E-14. If a built-in datum is being used, both the datum index and the five double-precision values for that index are returned. If the receiver is operating on a custom user-entered datum, the datum index is set to −1 and the five values are displayed.
A Trimble Standard Interface Protocol 00x8F-20 Report Packet 8F-20 Last Fix with Extra Information (binary fixed point) This packet provides information concerning the time and origin of the previous position fix. This is the last-calculated fix; it could be quite old. The receiver sends this packet in response to Packet 8E-20; it also can replace automatic reporting of position and velocity packets.
A Trimble Standard Interface Protocol Table A-87 Report Packet 8F-20 (Continued) Byte # Item/Type Meaning 25 Reserved 0 26 Datum Datum index +1 27 Fix Type / BYTE Type of fix. This is a set of flags.
A Trimble Standard Interface Protocol 0x8F-26 Report Packet 0x8F-26 Response to Save EEPROM Segments This report packet is output after the command packet 8E-26 has been executed.
A Trimble Standard Interface Protocol 0x8F-41 Report Packet 8F-41 Manufacturing Parameters This packet provides information on the manufacturing parameters stored in nonvolatile memory in response to command packet 8E-41.
A Trimble Standard Interface Protocol 0x8F-42 Report Packet 8F-42 Production Parameters This packet provides information on the production parameters stored in nonvolatile memory in response to command packet 8E-42.
A Trimble Standard Interface Protocol 0x8E-AD Command Packet 8E-AD (Request 8F-AD) Request or Configure Super Packet Output If the 8E-AD byte sequence is sent with no data, the receiver will generate an 8F-AD packet on port B. The time reported by the 8F-AD packet on port B is always the beginning of the current second. Output of the 8F-AD Primary UTC timing packet on Port A is configured by sending a 3 byte message 8E-AD n, where n ranges from 0 to 3, as defined below.
A Trimble Standard Interface Protocol 0x8F-4A Report Packet 8F-4A PPS Characteristics This packet reports ACE UTC’s PPS characteristics. This packet is sent in response to a query or control command with packet 8E-4A.
A Trimble Standard Interface Protocol 0x8F-4D Report Packet 8F-4D Automatic Packet Output Mask This packet provides information on the automatic packets that may be output by the receiver. Sent in response to 8E-4D query or set.
A Trimble Standard Interface Protocol Table A-95 Bit # Report Packet 8F-4D (Continued) Output Packets When Output Meaning 9 Reserved 10 Reserved 11 6D, 82 Constellation Change New satellite selection 12 Reserved 13-29 Reserved 30 4A, 8F-20, 42, 43, 54, 56, 82, 83, 84 New Fix Update Dynamic and Timing information. Output must be enabled with I/O options. 31 (Note 1) 5A New Fix Output must be enabled with I/O options.
A Trimble Standard Interface Protocol 0x8F-A6 Report Packet 8F-A6 This report packet is output after the command packet 8E-A6 has been executed and is identical in structure to packet 8E-A6. See the corresponding command packet for information about the data formats. 0x8F-A9 Report Packet 0x8F-A9 This report packet is output after the command packet 8E-A9 has been executed and is identical in structure to packet 8E-A9. See the corresponding command packet for information about the data formats.
A Trimble Standard Interface Protocol number roll-over occurred as August 21, 1999 (GPS) transitioned to August 22, 1999 (GPS). The ACE UTC GPS adjusts for this week rollover by adding 1024 to any week number reported by GPS that is less than week number 1023, which began on December 14, 1997. With this technique, the ACE UTC GPS will provide an accurate translation of GPS week number and TOW to time and date until July 30, 2017.
A Trimble Standard Interface Protocol Table A-96 Byte Item Type 0 Subcode BYTE 0xAB 1-4 Time of week ULONG GPS seconds of week 5-6 Week Number UINTEGER GPS Week Number (see above) 7-8 UTC Offset INTEGER UTC Offset (seconds) Timing Flag Bit Field 0 1 0 1 0 1 0 1 GPS time UTC time Reserved Reserved Time is set Time is not set Have UTC info No UTC info 10 Seconds BYTE 0-59 (60 for UTC leap second event) 11 Minutes BYTE 0-59 Minutes of Hour 12 Hours BYTE 0-23 Hour of Day
Trimble Standard Interface Protocol A 0x8F-AC Report Packet 8F-AC This report packet provides supplemental timing information once per second if enabled with command packet 8E-A5. Information regarding position, unit status and health, and the operational state of the unit is provided. This packet can be requested with command packet 8E-AC. When enabled, this packet is transmitted once per second shortly after report packet 8F-AB.
A Trimble Standard Interface Protocol Minor Alarms: This field is bitwise encoded with several minor alarm indicators. A minor alarm indicates a condition that the user should be alerted to, but does not indicate an immediate (or necessarily any) impairment of functionality. For each bit, a value of 0 means that the condition is not indicated. Bits not described below should be ignored.
Trimble Standard Interface Protocol A GPS Decoding Status: This field indicates the decoding status of the GPS receiver. Local Clock Offset: This field carries the offset of the local clock relative to UTC or GPS as reported by the GPS receiver in nanoseconds. Positive values indicate that the ACE UTC GPS’s local clock is late relative to GPS or UTC. Also known as bias.
A Trimble Standard Interface Protocol The table below identifies the fields associated with packet 8F-AC.
A Trimble Standard Interface Protocol Table A-97 Byte Bit Report Packet 8F-AC (Continued) Item Type Value Meaning 13 Reserved 14 Reserved 15 Reserved 16-19 Bias SINGLE Estimate of UTC/GPS offset (ns) of local clock 20-23 Bias Rate SINGLE Estimate of UTC/GPS offset (ppb) of local clock 24-27 Reserved 28-31 Reserved 32-35 Reserved 36-43 Latitude DOUBLE Radians 44-51 Longitude DOUBLE Radians 52-59 Altitude DOUBLE Meters 60-63 PPS Quantization Error Single PPS quantiza
A Trimble Standard Interface Protocol 0x8F-AD Report Packet 8F-AD Primary UTC Time The output of the 8F-AD packet is synchronized with the PPS, and may also be generated in response to external events. This packet provides accurate time and date information for time stamping and time transfer. The leap flag provides complete UTC event information, allowing implementation of sophisticated distributed systems intended to operate synchronously with UTC time.
A Trimble Standard Interface Protocol The tracking status flag allows precise monitoring of receiver tracking status and allows a host system to determine whether the time output by the receiver is valid. After self-survey has completed, the receiver only needs to track one satellite to maintain precise synchronization with UTC. Table A-99 Tracking Status Flag Definitions Flag Value Status Meaning 0 DOING_FIXES Receiver is navigating.
A Trimble Standard Interface Protocol Leap Second Flag Leap seconds are inserted into the UTC timescale to counter the effect of gradual slowing of the earth’s rotation due to friction. The 8F-AD packet provides extensive UTC leap second information to the user application. The Leap Scheduled bit is set by the receiver, when the leap second has been scheduled by the GPS control segment. The Control segment may schedule the leap second several weeks before the leap second takes place.
A Trimble Standard Interface Protocol A.18 Datums The table on the following pages lists datums. Table A-101 Datums Index DX DY 0 0 0 1 -128 481 2 -8 160 3 -9 4 -87 5 -133 6 DZ A-axis Eccentricity Description 0 6378137.000 0.00669437999014 /*WGS-84*/ 664 637797.155 0.00667437311265 /*Tokyo from old J6 values*/ 176 6378206.400 0.0067865799761 /*NAD-27*/ 151 185 6378206.400 0.00676865799761 /*Alaska/Canada*/ -98 -121 6378388.000 0.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 25 -125 -108 -295 6378249.145 0.00680351128285 /*Arc 1950-Lesotho*/ 26 -161 -73 -317 6378249.145 0.00680351128285 /*Arc 1950-Malawi*/ 27 -134 -105 -295 6378249.145 0.00680351128285 /*Arc 1950Swaziland*/ 28 -169 -19 -278 6378249.145 0.00680351128285 /*Arc 1950-Zaire*/ 29 -147 -74 -283 6378249.145 0.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 47 -263 6 431 6378249.145 0.00680351128285 /*Carthage*/ 48 175 -38 113 6378388.000 0.00672267002233 /*Chatham 1971*/ 49 -134 229 -29 6378388.000 0.00672267002233 /*Chua Astro*/ 50 -206 172 -6 6378388.000 0.00672267002233 /*Corrego Alegre*/ 51 -377 681 -50 6377397.155 0.00667437223180 /*Djakarta (Batavia)*/ 52 230 -199 -752 6378388.000 0.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 71 -156 -271 -189 6378388.000 0.00672267002233 /*Hong Kong 1963*/ 72 209 818 290 6377276.345 0.00663784663020 /*Indian-Thai/Viet*/ 73 295 736 257 6377301.243 0.00663784663020 /*Indian-India/Nepal*/ 74 506 -122 611 6377340.189 0.00667053999999 /*Ireland 1965*/ 75 208 -435 -229 6378388.000 0.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 97 -9 161 179 6378206.400 0.00676865799761 /*NAD 27-Eastern US*/ 98 -5 135 172 6378206.400 0.00676865799761 /*NAD 27-Alaska*/ 99 -4 154 178 6378206.400 0.00676865799761 /*NAD 27-Bahamas*/ 100 1 140 165 6378206.400 0.00676865799761 /*NAD 27-San Salvador*/ 101 -10 158 187 6378206.400 0.00676865799761 /*NAD 27-Canada*/ 102 -7 162 188 6378206.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 118 -130 110 -13 6378200.0 0.00669342162297 /*Old Egyptian 1907*/ 119 61 -285 -181 6378206.400 0.00676865799761 /*Old Hawaiianmean*/ 120 89 -279 -183 6378206.400 0.00676865799761 /*Old HawaiianHawaii*/ 121 45 -290 -172 6378206.400 0.00676865799761 /*Old Hawaiian*/ 122 65 -290 -190 6378206.400 0.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 138 -278 171 -367 6378388.0 0.00672267002233 /*Prov S. American 1956-Equador*/ 139 -298 159 -369 6378388.0 0.00672267002233 /*Prov S. American 1956-Guyana*/ 140 -279 175 -379 6378388.0 0.00672267002233 /*Prov S. American 1956-Peru*/ 141 -295 173 -371 6378388.0 0.00672267002233 /*Prov S. American 1956-Venez*/ 142 11 72 -101 6378206.4 0.
A Trimble Standard Interface Protocol Table A-101 Datums (Continued) Index DX DY DZ A-axis Eccentricity Description 158 -58 0 -44 6378160.0 0.00669454185459 /*S. American 1969Peru*/ 159 -45 12 -33 6378160.0 0.00669454185459 /*S. American 1969Trin/Tob*/ 160 -45 8 -33 6378160.0 0.00669454185459 /*S. American 1969Venezuela*/ 161 7 -10 -26 6378155.0 0.00669342162297 /*South Asia*/ 162 -499 -249 314 6378388.0 0.
A Trimble Standard Interface Protocol A.19 Sample TSIP Routines The following sections give sample routines that use command packet 0x1F and report packet 0× 45 for getting software version information from the ACE UTC GPS via COM1. Source code for a working TSIP monitor program is available at www.trimble.com/ support/files.
A Trimble Standard Interface Protocol All TSIP packet formats take the form , where and are reserved frame characters with values 0x10 and 0x03, respectively, and is the packet identifier. The following routines perform DLE stuffing on a command packet and send it to the ACE UTC GPS.
A Trimble Standard Interface Protocol To issue command packet 0x41 to request software version from the ACE UTC GPS use the following routine. /* Request software version */ void cmd_0x1F(void) { TSIPPKT cmd; cmd.cnt = 0; cmd.code = 0x1F; send_cmd(&cmd); } Handling incoming TSIP packet 0x45 Report routines handle incoming receiver packets.
A Trimble Standard Interface Protocol case ETX: /* End of message. */ rpt->status = COMPLETE; return(TRUE); default: /* If previous message has ended, this is new ID code. */ reset_rptbuf(rpt); /* if not, this is an error. */ rpt->code = this_byte; return(FALSE); } } else if (this_byte == DLE) { /* DLE byte without previous DLE stuffing…must be stuffing.
Trimble Standard Interface Protocol A-138 A Acutime 2000 Synchronization Kit User Guide
B Timing Receiver Monitor The Timing Receiver Monitor program disk is included with the Acutime 2000 Synchronization Kit. The latest version of the program is also available on the Trimble website: • B.1 www.trimble.com/products/acutime2000 Start-Up The Serial Port Selection screen shown below appears at the start of the program: This screen lets you choose which PC serial port the Acutime 2000 is connected to.
B Timing Receiver Monitor B.2 Main screen The main screen for the Timing Receiver Monitor is shown below: The main screen displays time, position, SV selection and data, receiver status, and timing outputs. The status bar displays Tx and Rx activity, program hints, firmware version number, and serial port settings. The menu provides other options for sending data to and requesting data from the receiver. For additional program information and help, see the Help menu.
C NMEA 0183 NMEA 0183 is an interface protocol created by the National Marine Electronics Association. The latest release of NMEA 0183 is Version 2.1 (October 15, 1995). This protocol was originally established to allow marine navigation equipment to share information. NMEA 0183 is a simple, yet comprehensive ASCII protocol which defines both the communication interface and the data format.
C NMEA 0183 C.1 The NMEA 0183 Communication Interface NMEA 0183 allows a single source (talker) to transmit serial data over a single twisted wire pair to one or more receivers (listeners). The table below lists the characteristics of the NMEA 0183 data transmissions. Table C-1 C.2 NMEA 0183 Characteristics Signal Characteristic NMEA Standard Baud Rate 4800 Data Bits 8 Parity None (Disabled) Stop Bits 1 NMEA 0183 Message Format The NMEA 0183 protocol covers a broad array of navigation data.
C NMEA 0183 Dn Each message contains multiple data fields (Dn), which are delimited by commas. “*” The asterisk serves as a checksum delimiter. CS The checksum field contains two ASCII characters which indicate the hexadecimal value of the checksum. [CR][LF] The carriage return [CR] and line feed [LF] combination terminate the message. NMEA 0183 messages vary in length, but each message is limited to 79 characters or less. This length limitation excludes the “$” and the [CR][LF].
C NMEA 0183 C.3 NMEA 0183 Message Options The Acutime 2000 can output any or all of the messages listed in Table C-2. When NMEA is chosen, its default configuration (as shipped from the factory) outputs two messages: GGA and VTG. These messages are output at a one-second interval with the “GP” talker ID and checksums. ! # Note – The user can configure a custom mix of the messages listed in Table C-2.
C C.4 NMEA 0183 NMEA 0183 Message Formats The format for each message is described in more detail in the following sections. C.4.1 GGA – GPS Fix Data The GGA message includes time, position and fix related data for the GPS receiver. $GP GGA,hhmmss,llll.lll,a,nnnnn.nnn,b,t,uu,v.v,w.w, M,x.x,M,y.
C NMEA 0183 C.4.2 GLL – Geographic Position – Latitude/Longitude The GLL message contains the latitude and longitude of the present vessel position, the time of the position fix and the status. $GP GLL,llll.lll,a,yyyyy.yyy,a,hhmmss.
C NMEA 0183 C.4.3 GSA – GPS DOP and Active Satellites The GSA messages indicates the GPS receiver's operating mode and lists the satellites used for navigation and the DOP values of the position solution. $GP GSA,a,x,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx, xx,xx,x.x,x.x,x.x*hh Table C-5 GSA – GPS DOP and Active Satellites Message Parameters Field # Description 1 Mode: M = Manual, A = Automatic. In manual mode, the receiver is forced to operate in either 2D or 3D mode.
C NMEA 0183 C.4.4 GSV – GPS Satellites in View The GSV message identifies the GPS satellites in view, including their PRN number, elevation, azimuth and SNR value. Each message contains data for four satellites. Second and third messages are sent when more than four satellites are in view. Fields #1 and #2 indicate the total number of messages being sent and the number of each message respectively.
C NMEA 0183 C.4.5 RMC – Recommended Minimum Specific GPS/Transit Data The RMC message contains the time, date, position, course, and speed data provided by the GPS navigation receiver. A checksum is mandatory for this message and the transmission interval may not exceed two seconds. All data fields must be provided unless the data is temporarily unavailable. Null fields may be used when data is temporarily unavailable. $GP RMC,hhmmss.s,A,llll.lll,a,yyyyy.yyy,a,x.x,x.x, xxxxxx,x.
C NMEA 0183 C.4.6 VTG – Track Made Good and Ground Speed The VTG message conveys the actual track made good (COG) and the speed relative to the ground (SOG). $GP VTG,x.x,T,x.x,M,x.x,N,x.x,K*hh Table C-8 C-10 VTG – Track Made Good and Ground Speed Message Parameters Field # Description 1 Track made good in degrees true. 2 Track made good in degrees magnetic. 3,4 Speed over the ground (SOG) in knots. 5,6 Speed over the ground (SOG) in kilometer per hour.
C NMEA 0183 C.4.7 ZDA – Time & Date The ZDA message contains UTC, the day, the month, the year and the local time zone. $GP ZDA,hhmmss.s,xx,xx,xxxx,,*hh Table C-9 ! ZDA – Time & Date Message Parameters Field # Description 1 UTC 2 Day (01 to 31) 3 Month (01 to 12) 4 Year 5 unused 6 unused hh Checksum Note – Fields #5 and #6 are null fields in the Acutime 2000 output. A GPS receiver cannot independently identify the local time zone offsets.
NMEA 0183 C-12 C Acutime 2000 Synchronization Kit User Guide
D Specifications and Drawings This appendix contains the specifications for the Acutime 2000 GPS smart antenna and a diagram of the Acutime 2000 Interface Cable. ! D.1 Note – The interface cable specifications provided in this appendix are for the 100-foot (30-meter) versions of the cables. Longer versions of these cables are available. The specifications for the longer cables are identical to that of the 100-foot version.
D Specifications and Drawings Table D-2 Environmental Specifications Operating temp: -40 to +85° C Storage temp: -55 to +105° C Vibration: 0.008 g2/Hz 0.05 5 Hz to 20 Hz g2/Hz 20 Hz to 100 Hz -3dB/octave Table D-3 100 Hz to 900 Hz Operating Humidity: 95% RH, non-condensing @ 60° C EMC: CE, FCC Class B Performance Specifications General: L1 frequency, C/A code (SPS), continuous tracking receiver.
D Table D-3 Specifications and Drawings Performance Specifications (Continued) Acceleration: 4g (39.2 m/sec.2) Jerk: 20 m/sec.3 PPS output Physical Interface: RS-422 Width: 10 microseconds (default). User-programmable from 10 microseconds to 500 milliseconds. On-Time Edge: Rising edge on-time (default). User-programmable rising or falling.
D Specifications and Drawings Table D-5 Serial Protocols Port Interface Protocols Defaults TxB (primary) RS-422/485 or RS-232 TSIP, NMEA TSIP @ 9600, 8-odd-1 RxB (primary) RS-422/485 or RS-232 TSIP TSIP @ 9600, 8-odd-1 TxA (secondary) RS-422/485 or RS-232 TSIP TSIP @ 9600, 8-odd-1 RxA (secondary) RS-422/485 or RS-232 Event/RTCM Event Input All ports support baud rates of 300-38,400; 8 data bits; even, odd, no parity NMEA messages (default): ZDA Available messages: GGA, GLL, VTG, G
D D.2 Specifications and Drawings Acutime 2000 Standard Interface Cable Diagram Figure D-1 provides a technical drawing of the Acutime 2000 standard interface cable.
D Specifications and Drawings 50' ±6" 1.6"±0.1" REF Pin 10 Pin 1 4.0" ±1.
Specifications and Drawings Figure D-2 D-7 NTP Interface Cable D
Specifications and Drawings D-8 D
E E.1 NTP Diagnostics and Debugging Diagnostics and Debugging This section presents common reports and failure conditions that may occur on Windows NT and UNIX systems, and provides suggestions for their possible sources. ! E.1.1 Note – Administrators should check the system’s log files periodically. Failures usually do not occur unexpectedly, and can be averted in many cases. System Log Entries The system log entries are shown here in a Windows NT context.
E NTP Diagnostics and Debugging Serial Port Acces Report The configuration of the Acutime NTP reference clock is acknowledged by a report of the COM port used by the driver. Verify that the correct port is being used by NTP. If this message does not appear, there has been a failure. Refresh the system log to observe additional error messages.
E NTP Diagnostics and Debugging E.1.2 Error Log Entries The following entries show NTP errors that degrade system operation. These failures should be corrected immediately. Configuration File Not Found If the Configuration File is not found, the following event log entry will be generated: On a UNIX system, the message will report the file name .
E NTP Diagnostics and Debugging ! # Note – If you are using Windows NT, please review Create the Configuration File, page 6-17 to ensure the configuration file is named correctly. Warning – NTP does not stop because of this error. Provide a valid configuration file, and stop and re-start NTP. For more information on correcting this error, see NTP Configuration File, page 6-11.
E NTP Diagnostics and Debugging Acutime Configuration Failure An Event Log message that indicates a problem configuring the Acutime NTP reference clock is shown below: This message is accompanied by additional messages indicating the source of the failure.
E NTP Diagnostics and Debugging COM Port Unavailable If the COM port defined in the NTP configuration file is not found, or is locked by another application, the following Application Event Message is generated: This message is unique to Windows NT, but the solution is based on general guidelines. For more information on resolving device unavailablility, see page E-16.
E NTP Diagnostics and Debugging System Clock Not Set The system clock must be set close to the correct local time. If NTP finds the system clock too far offset, it will stop and report the following error: Solution: The sample screen below demonstrates using NTPDATE to reset UNIX system time to another NTP server. The utility requires an additional –b parameter behind the server name when run on Windows NT. If you cannot use NTPDATE, use your system’s native clock function to reset the system clock.
E NTP Diagnostics and Debugging E.2 Running NTP in Debug Mode NTP can be run in debug mode as a foreground command line application. In this mode, messages reporting system events are printed to the screen, which reveal more information about errors and problems encountered by the program. In order to be able to quickly diagnose communication problems with the Acutime, it is helpful to have a debug version of NTP available.
E NTP Diagnostics and Debugging E.2.1 Debug Mode Not Available If NTP is not compiled in debug mode, it will report: ntpd not compiled with -DDEBUG option - no DEBUG supportusage: ... E.2.
E NTP Diagnostics and Debugging The Acutime NTP reference clock driver reports requests and receipt of the time stamp data. Typical Acutime NTP time transfer debug output appears as four lines in the debug output, as shown here. Palisade_poll: unit 0: polling event Palisade_receive: unit 0: 1999 131 06:25:36.981446 Palisade_receive: unit 0: bae24be0.fc549b62 Mon, May 10 1999 23:25:36.985 refclock_receive: at 18 127.127.29.0 The Acutime driver reports the GPS time stamp in the first Acutime_receive line.
E NTP Diagnostics and Debugging E.2.3 Acutime is not Responding If the Acutime smart antenna is not responding to polls, the following output is generated in the debug stream: The last two lines of output on this screen show the Acutime NTP driver reporting failure to receive a time stamp from the GPS. These messages indicate that NTP is not receiving data from the reference clock.
E NTP Diagnostics and Debugging Table E-1 shows troubleshooting options. Table E-1 Troubleshooting: Acutime is Not Responding Possible Problem Solution Cabling or connectors have become detached. Connect and secure loose or disconnected cables and connectors. System does not support event polling. Configure fallback to synchronous polling mode. Update NTP software. No activity of Power or PPS indicators on the Acutime Synchronization Interface Module. Confirm availability of wall power.
E NTP Diagnostics and Debugging To configure NTP to disable output you need to edit the configuration file and add the line: fudge 127.127.127.x flag2 1 Then run NTP in debug mode (ntpd -d), to observe Palisade_receive events.
E NTP Diagnostics and Debugging Receive events generated without event polling should be reported as poll events of this format: Palisade_poll: unit x: polling synchronous packet The seconds value reported by the Acutime NTP reference clock is always an integer, since the synchronous packets are always transmitted at the beginning of the second.
E NTP Diagnostics and Debugging After confirming functionality of NTP using synchronous packets, you can remove fudge flag2 from the configuration file and restart NTPD in debug mode to observe event polling receive events. E.2.5 Incorrect Port and Bad Data If the Acutime NTP driver detects invalid packet data on the serial line, it generates debug messages similar to the following.
E NTP Diagnostics and Debugging E.2.6 Serial Port is Unavailable When NTP is unable to open a serial port, the following debug message is generated, along with an error report in the system log: Palisade(2) start: open /dev/Acutime2 failed A failed serial port open attempt is shown below: On a Windows NT system, the device name would refer to a device such as COM1: Possible Problems: • The configured serial port is not actually present on the system.
E NTP Diagnostics and Debugging • Other services or applications are attempting to use the same port as NTP. Solution: Reconfigure NTP or the conflicting application to resolve the conflict. E.3 Compiling the NTP Distribution To obtain compatibility updates, download the latest published versions of the Acutime NTP reference clock I/O module and associated documentation from: ftp://ftp.trimble.
E NTP Diagnostics and Debugging E-18 5. Start configuration by typing: ./configure 6. If the configuration program fails, or does not complete by creating make files, you will need to consult with your software or system administrator to obtain the correct compiler and libraries for your system. 7. After configuration is complete, type make to begin the software build. If the build does not complete sucessfully, please consult with your software or system administrator to diagnose the problem.
E NTP Diagnostics and Debugging NTP installs into the directory /USR/LOCAL/BIN. If you wish to install into a different directory, please consult the NTP documentation. 8. To install NTP into the default directory, log in as super user, or root, and type make install from the NTP-4.XX.XX directory.
E NTP Diagnostics and Debugging To complete installation of NTP on your system, see UNIX Installation, page 6-24.
E NTP Diagnostics and Debugging E.4 Windows NT Administration This section describes starting and stopping NTP on Windows NT, and removing the NTP service from the system. E.4.1 Controlling the NTP Service Use the Control Panel Services Applet to Stop or Disable the NTP service at any time. This procedure is the same whether you installed the NTP service manually or using the installation program. E.4.
E NTP Diagnostics and Debugging 2. Start a command prompt window, and change to the directory containing the INSTSRV.EXE utility. 3. Type instsrv remove. The program reports successful removal of the service. The executable files copied during installation, as well as the configuration file must be manually removed from the system if a permanent installation is desired. This concludes the manual Windows NT installation.
E E.5 NTP Diagnostics and Debugging Additional Information For up-to-date hardware, software, and configuration information, please refer to the Trimble Navigation NTP Web Site at www.trimble.com/oem/ntp.
NTP Diagnostics and Debugging E-24 E Acutime 2000 Synchronization Kit User Guide
F Theory of Operation This chapter describes the smart antenna's satellite acquisition and tracking processes, performance characteristics and system architecture. This discussion assumes you are familiar with basic GPS theory. The smart antenna's satellite acquisition and tracking algorithms can achieve a position solution without any initialization. The receiver tracks up to eight satellites and automatically selects the best combination of satellites to compute position, velocity and time.
F Theory of Operation F.1 GPS Satellite Message Every GPS satellite transmits the Coarse/Acquisition (C/A) code and satellite data modulated onto the L1 carrier frequency (1575.42 MHz). The C/A code is a unique pseudo-random sequence for each satellite. The satellite data transmitted by each satellite includes a satellite almanac for the entire GPS system, its own satellite ephemeris, and its own clock correction. The satellite data is transmitted in 30-second frames.
F Theory of Operation F.2 Satellite Acquisition and Time to First Fix This section describes satellite acquisition times for different start conditions. F.2.1 Cold Start The term cold start describes the performance of a GPS receiver at power-on when no navigation data is available. Cold signifies that the receiver does not have a current almanac, satellite ephemeris, initial position, or time.
F Theory of Operation F.2.2 Warm Start In a warm start condition, the receiver has a current almanac, an initial position (within 3,000 km) and current time (within five minutes) stored in memory. Although the smart antenna does not have an onboard battery for preserving memory, it can be initialized using the TSIP protocol. To force a warm start, the almanac, time, and initial position must be uploaded to the receiver.
F Theory of Operation F.2.3 "Garage Search" Strategy During a warm start search, the smart antenna knows which satellites to search for, based on the system almanac, the initial position and the current time. In some cases, the receiver may not be able to acquire the expected satellite signals (for example, if the Acutime 2000 is in a jamming environment). Trimble's patented garage search strategy, also known as a split search, is designed for such situations.
F Theory of Operation F.3 Position Accuracy GPS position accuracy is degraded by atmospheric distortion, satellite and receiver clock errors, and Selective Availability (S/A). Effective models for atmospheric distortion of satellite signals have been developed to minimize the impact of tropospheric and ionospheric effects. The impact of satellite clock errors is minimized by incorporating the clock corrections transmitted by each satellite used in the position solution.
F Theory of Operation F.4 Coordinate Systems This section lists the coordinate system formats supported by the TSIP and NMEA 0183 protocols. F.4.1 TSIP In the default TSIP configuration, position is output in a LatitudeLongitude-Altitude (LLA) format based on a default datum, WGS-84. The LLA format can be easily converted by the host system to other coordinate systems using the appropriate translation algorithm.
F Theory of Operation F.5 Performance Characteristics This section lists performance information for the Acutime 2000. F.5.1 Update Rate The Acutime 2000 updates position at one-second intervals during self-survey. The surveyed position is frozen after the survey completes. F.5.2 Dynamic Limits The dynamic operating limits for the various receiver designs are listed below.
F Theory of Operation If ephemeris or almanac data is available for the lost satellite, then the satellite's velocity is factored into the center frequency calculation. The diminished accuracy of an older almanac is accounted for in the width of the search range. If neither the ephemeris nor almanac is available, then the Doppler frequency at last lock is searched for two minutes.
F Theory of Operation F.6 System Architecture The standard Acutime 2000 incorporates a proprietary DSP (Digital Signal Processor), which operates at the L1 frequency (1575.42 MHz) and processes the Coarse/Acquisition (C/A) code portion of the GPS signal. The RF and digital signal processing components of the GPS module are custom ASICs designed by Trimble. In addition to the signal processing functions, these ASICs also contain support circuitry for the microprocessor.
F Theory of Operation Acutime 2000 12-Pin Connector Internal Patch Antenna Preamp RF ASIC RF In Tx 4 Port B Tx Rx 2 Port B Rx Microcontroller/ Tx GPS Receiver Port A ASIC Rx 7 Port A Tx Event In 6 Event In / Port A Rx PPS Out 11 12 PPS Out (+) PPS Out (-) 8 VBack 1 9 DC Power In Ground Port B TCXO 12.
Theory of Operation F-12 F Acutime 2000 Synchronization Kit User Guide
Glossary This section defines technical terms and abbreviations used in this manual. It includes terms from the field of GPS technology. 2-D Two Dimensional. A 2-D position is defined as latitude and longitude. Altitude is assumed to be fixed. 2-D GPS mode A procedure of determining a 2-D position using signals received from the best (or only) three available GPS satellites. Altitude is assumed to be known and constant.
Glossary ASCII American Standard Code for Information Interchange. A standard set of 128 characters, symbols and control codes used for computer communications. ASCII characters require 7 bits of data to send, but are often sent 8 bits at a time with the extra bit being a zero. auto GPS mode A procedure of automatically determining either a 2-D or 3D position using signals received from GPS satellites.
Glossary C/A code The Coarse/Acquisition code. This is the civilian code made available by the Department of Defense. It is subject to selective availability (SA). Users can reduce the effects of SA by using differential GPS. carrier The radio signal on which information is carried. The carrier can be sensed to determine the presence of a signal. channel Either a single frequency or a pair of radio frequencies used as a communication path.
Glossary differential relative positioning Determination of relative coordinates of two or more receivers which are simultaneously tracking the same satellites. Static differential GPS involves determining baseline vectors between pairs of receivers. Also see differential GPS.
Glossary elevation mask angle A measure of the minimum elevation angle, above the horizon, above which a GPS satellite must be located before the signals from the satellite will be used to compute a GPS location solution. Satellites below the elevation angle are considered unusable. The elevation mask angle is used to prevent the GPS receiver from computing position solutions using satellites which are likely to be obscured by buildings or mountains.
Glossary GDOP Geometric Dilution of Precision. GDOP describes how much an uncertainty in pseudo-range and time affects the uncertainty in a position solution. GDOP depends on where the satellites are relative to the GPS receiver and on GPS clock offsets. geodetic datum A mathematical model designed to best fit part or all of the geoid. It is defined by an ellipsoid and the relationship between the ellipsoid and a point on the topographic surface established as the origin of datum.
Glossary GPS Global Positioning System. A satellite-based navigation system operated and maintained by the U.S. Department of Defense and consisting of a constellation of 24 satellites providing worldwide, 24-hour, three-dimensional (3-D) GPS coverage. These satellites transmit signals used (by GPS receivers) to determine precise location (position, velocity, and time) solutions. GPS signals are available in all weather conditions.
Glossary interface cable The interface cable allows data to flow between the Acutime 2000 and the communication equipment. interference Refers to the unwanted occurrences on communication channels that are a result of natural or man-made noises and signals, not properly a part of the signals being transmitted or received. integrated Doppler A measurement of Doppler shift frequency or phase over time. IODE Issue Of Data, Ephemeris. Part of the navigation data.
Glossary packet An "envelope" for data, which contains addresses and error checking information as well as the data itself. parity A scheme for detecting certain errors in data transmission. Parity defines the condition (i.e., even or odd) of the number of items in a set (e.g., bits in a byte). PDOP Position Dilution of Precision. PDOP is a unitless figure of merit that describes how an uncertainty in pseudo-range affects position solutions.
Glossary range A term used to refer to the distance radio signals can travel before they must be received or repeated due to loss of signal strength, the curvature of the earth and the noise introduced because of moisture in the air surrounding the earth's surface. range rate The rate of change of range between the satellite and receiver. The range to a satellite changes due to satellite and observer motions. Range rate is determined by measuring the Doppler shift of the satellite beacon carrier.
Glossary satellite masks As satellites approach the horizon, their signals can become weak and distorted, preventing the receiver from gathering accurate data. Satellite masks enable you to establish criteria for using satellite data in a position solution. There are three types of satellite masks: Elevation, SNR, and PDOP. SA Selective Availability.
Glossary SPS Standard Positioning Service. Refers to the GPS as available to the authorized user. start bit In asynchronous transmission, the start bit is appended to the beginning of a character so that the bit sync and character sync can occur at the receiver equipment. stop bit In asynchronous transmission, the stop bit is appended to the end of each character. It sets the receiving hardware to a condition where it looks for the start bit of a new character. SV Space Vehicle (GPS satellite).
Index A C abbreviations used in manual xxiii Acutime 2000 GPS Smart Antenna 12-pin connector format 4-3 communicating with 2-4 connecting 2-2 connecting host system 3-6 connection diagram 2-3 connections 4-1 enclosure illustration 1-3 installation choosing location 3-2 routing and securing interface cable 3-5 installing 2-1, 3-1 interface cables and connectors 4-4 interface connector 4-3 mounting 3-4 overview 1-2 specifications D-1 start-up 5-1 almanac A-40, A-58 Appendix F, Theory of Operation xxi, 5-1 A
E M ECEF A-30 electrical specifications D-3 elevation mask 5-2 environmental specifications D-2 event input 4-9 external event input 5-9 main screen B-2 manual installation Windows NT 6-17 monitoring NTP 6-31 mounting the smart antenna 3-4 N G garage search strategy F-5 getting started 2-1 Glossary Glossary-1 GPS timing 5-12 H HAE A-30 health of receiver A-46 health of satellite A-49 height above ellipsoid A-30 hot start F-5 I installation 3-1 software 6-1 UNIX 6-24 Windows NT 6-15 interface and power
update rate F-8 performance specifications D-2 physical specifications D-1 pin-out descriptions 4-5 position accuracy F-6 selective availability F-6 power connection 4-7 PPS output options 5-6 PPS quantization error 5-6, 5-7 pre-installation check list 6-4 preparation GPS 6-5 host system 6-6 R raw measurement data A-38 re-acquisition F-8 reader comment form 5 report packets A-16 routing interface cable 3-5 S satellite acquisition F-3 cold start F-3 garage search strategy F-5 hot start F-5 warm start F-4 s
0x4C, Operating Parameters Report A-52 0x4E, GPS Time Change Acknowledgment A-53 0x57, Information About Last Computed Fix Report A-57 0x59, Satellite Attributes Database Report A-63 0x5A, Raw Measurement Data Report A-64 0x5C, Satellite Tracking Status Report A-68 0x5F, EEPROM Segment Status Reports A-70 U unit number 6-12 UNIX installation 6-24 hardware configuration 6-28 update notes xxii update rate F-8 W warm start F-4 Windows NT installation 6-15 automatic 6-16 manual 6-17 World Wide Web (WWW) site
Reader Comment Form Acutime 2000 Synchronization Kit User Guide P/N: 45005-00-ENG April 2001 Revision A We appreciate your comments and suggestions for improving this publication. Contributors of particularly helpful evaluations will receive a thank-you gift.
