GM-83 GPS Engine Board User's Guide Version: 2.0 HOLUX Technology Inc. 8F, 26, Tai-Yuen Street, Tai-Yuen Hi-Tech Industrial Park, Chu Pei City 302, Hsinchu, Taiwan. Phone: +886-3-552-6268 Fax: +886-3-552-6108 E-Mail: info@holux.com.tw Web: www.holux.com.tw All Right Reserved GM-83 User's manual TABLE OF CONTENTS 1. Introduction .............................................................................................. 1.1 Overview ........................................................................................... 1.2 Features ........................................................................................... 1.3 Technical Specifications ........................................................................... 3 3 3 3 2. Operational Characteristics 2.1 Initialization 2.2 Navigation ..................................................................... ....................................................................................... 4 4 ....................................................................................... 5 3. Hardware Interface .................................................................................... 6 3.1 Standard Model .................................................................................. 6 4. Software Interface .................................................................................... .................................................................... 8 4.1 NMEA Transmitted Sentences 4.2 RTCM Received Data 8 ............................................................................ 11 5. Earth Datums ............................................................................................. 12 5.1 Earth Datums ..................................................................................... 12 5.2 Manufacture Default ................................................................................. 13 6. Ordering Information ................................................................................ 6.1 Product Options ................................................................................. 6.2 Accessories ....................................................................................... 6.3 Other Products .................................................................................. 14 14 14 14 2 GM-83 User's manual 1. Introduction 1.1 Overview The HOLUX GM-83 Engine Board is a total solution GPS receiver, designed based on SiRF star II Architecture. This positioning application meets strict needs such as car navigation, mapping, surveying, agriculture and so on. Only clear view of sky and certain power supply are necessary to the unit. GM-83 communicates with other electronic utilities via compatible dual-channel through RS-232 or TTL and saves critical satellite data by built­in memory backup. With low power consumption, the GM-83 tracks up to 12 satellites at a time, re-acquires satellite signals in 100 ms and updates position data every second. Trickle-Power allows the unit operates a fraction of the time and Push-to-Fix permits user to have a quick position fix even though the receiver usually stays off. 1.2 Features The GM-83 provides a host of features that make it easy for integration and use. SiRF Star II/LP chipset with embedded ARM7TDMI CPU available for customized applications in firmware 12 parallel satellite-tracking channels for fast acquisition and reacquisition High speed signal acquisition using 1920 time/frequency search channels Built-in WAAS/EGNOS Demodulator Support U.S. Coast Guard DGPS beacon signal Low power consumption with Advanced Trickle-Power and Push-To-Fix mode Optional Rechargeable battery for memory and RTC backup and for fast Time to First Fix(TTFF) Support NMEA0183 v2.2 data protocol and SiRF binary code Enhanced algorithms -SnapLock and SnapStart provide superior navigation performance in urban, canyon and foliage environments For Car Navigation , Marine Navigation ,Fleet Management ,AVL and Location-Based Services , Auto Pilot ,Personal Navigation or touring devices, Tracking devices/systems and Mapping devices application 1.3 Technology Specifications 1.3.1 Physical Dimension 1) PCB Size: 40.6(W) x 71.1(D) x 9.1(H) (mm) (The height of pin is excluded) 2) Weight: 18 g 1.3.2 Environmental Characteristics 1) Operating temperature: -40oC to +85oC (internal temperature) 2) Storage temperature: -45oC to +100oC 1.3.3 Electrical Characteristics 1) Less than 75mA (without antenna ) 2) Backup power:(optional)3V Rechargeable Lithium cell battery, up to 1000 hours discharge. 3) MCX antenna connector: Active. 3 GM-83 User's manual 1.3.4 Performance 1) Tracks up to 12 satellites. 2) Update rate: 1 second. 3) Acquisition time: Reacquisition Hot start Warm start Cold start 4) Position accuracy: Non DGPS (Differential GPS) Position 5~25 Velocity 0.1 Time 1 DGPS (Differential GPS) Position Velocity EGNOS/WAAS Position 5) Dynamic Conditions: Altitude Velocity Acceleration Jerk 18,000 515 4 20 meters(60,000 feet) max meters/second (700 knots) max G, max meters/second³, max 1 to 5 0.05 < 2.2 <5 meter CEP meters/second. microsecond synchronized GPS time meters, typical meters/second, typical meters, horizontal 95% of time meters, vertical 95% of time 0.1 8 38 45 sec, averaged sec. averaged sec. averaged sec. averaged 1.3.5 Interfaces 1) Dual communication channel TTL or RS232 levels, with user selectable baud rate (4800-Default, 9600, 19200, 38400). 2) NMEA 0183 Version 2.2 ASCII output (GPGGA, GPGLL, GPGSA, GPGSV (5 seconds) (GPRMC, and GPVTG for optional)). 3) Real-time Differential Correction input (RTCM SC-104 message types 1, 2 and 9). 2. Operational characteristics 2.1 Initialization As soon as the initial self-test is complete, the GM-83 begins the process of satellite acquisition and tracking automatically. Under normal circumstances, it takes approximately 45 seconds to achieve a position fix, 38 seconds if ephemeris data is known. After a position fix has been calculated, information about valid position, velocity and time is transmitted over the output channel. The GM-83 utilizes initial data, such as last stored position, date, time and satellite orbital data, to achieve maximum acquisition performance. If significant inaccuracy exists in the initial data, or the orbital data is obsolete, it may take more time to achieve a navigation solution. The GM-83 Auto-locate feature is capable of automatically determining a navigation solution without intervention from the host system. However, acquisition performance can be improved as the host system initializes the GM-83 in the following situation: Moving further than 500 kilometers. Failure of Data storage due to the inactive internal memory battery. 4 GM-83 User's manual 2.2 Navigation After the acquisition process is complete, the GM-83 sends valid navigation information over output channels. These data include: 1) 2) 3) 4) 5) Latitude/longitude/altitude Velocity Date/time Error estimates Satellite and receiver status 2.3 Manufacturing Default: Datum: WGS84. Baud Rate: 4800. Output: GGA, GSA, GSV, RMC or by demand. DGPS: RTCM SC-104(Type 1,2,9) or WAAS (in USA area) or EGNOS (in European area) 5 GM-83 User's manual 3. Hardware interface 3.1 Standard Model GM-83 GM-83-A W/ angle MCX connector and standard hole to hole dimension Pin # 1 2 3 4 5 6 7 8 9 10 Name NC VCC_5V VBAT NC PBRESEN GPIO1 GPIO2 GPIO3 GPIO4 GND J1 connector pin definition: Description No function Regulated 5.0V +/-5% input power, 160mA typical. Battery backup input. 2.5V to 3.3V ,10uA typical. No function Manual reset input, ground to reset receiver. Leave floating for normal operation. The minimum plus width is 150 ms reset signal. General purpose I/O pin 1 General purpose I/O pin 2 General purpose I/O pin 3 General purpose I/O pin 4 Ground 6 GM-83 User's manual 11 12 13 14 15 16 17 18 19 20 TXA RXA GND TXB RXB GND GPIO5 GND TIMEMARK NC Port A Serial Transmit Data GPS messages. Port A Serial Receive Data GPS commands. Ground Port B Serial Transmit Data. Port B Serial Receive Data DGPS messages. Ground. Reserved for re-programming flash. Ground 1PPS Time mark output No function 1. VCC_5V: + 5V DC voltage input. 2. Dual communication channel TTL levels (GM-83-T0/T1) or RS-232 levels (GM-83-A0/A1), with user selectable baud rates (4800-Default, 9600, 19200, 38400). RXA: Main Receive Channel. This input is used to receive software commands to the GM-83 from user written software. RXB: Auxiliary Receive Channel. This input is used to receive serial differential GPS data. TXA: Main Serial Output. This output provides navigation data to user written software. TXB: For user's application (not currently used). 3. PBRESEN: This pin provides an active-low reset input to the GM-83. Activation of this pin will reset and start acquisition process. It may be left open if not utilized. 4. TIMEMARK: This pin provides One-Pulse-Per-Second output from the GM-83 board, which is synchronized to GPS time. This is not available in Trickle-Power mode. 5. VBAT: Battery backup input for powering the RAM and RTC. Typical current is 10uA. Without an external backup battery the GM-83 will execute a cold start when turning on each time. To achieve the faster start-up offered by a hot or warm start, either a battery backup must be connected. A 2.5V and 3.6V power source is required in order to maximize battery lifetime. With a lithium cell battery, the data retention is 1,000 hours. 6. GPIO Functions: Several I/Os of CPU are connected to the digital interface connector for customer's applications and are labeled as GPIO1 to GPIO5. 7 GM-83 User's manual 4. Software Interface The GM-83 interface protocol is based on the National Marine Electronics Association's NMEA 0183 ASC interface specification, which is defined in NMEA 0183, Version 2.2 and the Radio Technical Commission for Maritime Services (RTCM Recommended Standards For Differential Navstar GPS Service, Version 2.1, RTCM Special Committee No.104). 4.1 NMEA Transmitted Messages The default communication parameters for NMEA output are 4800 baud, 8 data bits, stop bit, and no parity. Table 4-1 NMEA-0183 Output Messages NMEA Record Description GPGGA Global positioning system fixed data GPGLL Geographic position- latitude/longitude GPGSA GNSS DOP and active satellites GPGSV GNSS satellites in view GPRMC Recommended minimum specific GNSS data GPVTG Course over ground and ground speed GPMSS Radio-beacon Signal-to-noise ratio, signal strength, frequency, etc. 4.1.1 Global Positioning System Fix Data (GGA) Table 4-2 contains the values for the following example: $GPGGA,161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M, , , ,0000*18 Name Table 4-2 GGA Data Format Example Units Description Message ID $GPGGA UTC Time 161229.487 Latitude 3723.2475 N/S Indicator N Longitude 12158.3416 E/W Indicator W Position Fix Indicator 1 Satellites Used 07 HDOP 1.0 MSL Altitude (1) 9.0 Units M Geoid Separation(1) Units M Age of Diff. Corr. Diff. Ref. Station ID 0000 Checksum *18 GGA protocol header hhmmss.sss ddmm.mmmm N=north or S=south dddmm.mmmm E=east or W=west See Table 5-3 Range 0 to 12 Horizontal Dilution of Precision Meters Meters Meters Meters second Null fields when DGPS is not used End of message termination (1). SiRF Technology Inc. does not support geoid corrections. Values are WGS84 ellipsoid heights. Value Table 4-3 Position Fix Indicator Description 0 1 2 3 0 Fix not available or invalid GPS SPS Mode, fix valid Differential GPS, SPS Mode, fix valid GPS PPS Mode, fix valid 8 GM-83 User's manual 4.1.2 Geographic Position with Latitude/Longitude(GLL) Table 4-4 contains the values for the following example: $GPGLL,3723.2475,N,12158.3416,W,161229.487,A*2C Name Table 4-4 GLL Data Format Example Units Description Message ID Latitude N/S Indicator Longitude E/W Indicator UTC Position Status Checksum $GPGLL 3723.2475 N 12158.3416 W 161229.487 A *2C GLL protocol header ddmm.mmmm N/S Indicator N N=north or S=south dddmm.mmmm E=east or W=west hhmmss.sss A=data valid or V=data not valid End of message termination 4.1.3 GNSS DOP and Active Satellites (GSA) Table 4-5 contains the values for the following example: $GPGSA,A,3,07,02,26,27,09,04,15, , , , , ,1.8,1.0,1.5*33 Name Table 4-5 GSA Data Format Example Units Description Message ID Mode 1 Mode 2 Satellite Used(1) Satellite Used(1) ...... Satellite Used(1) PDOP HDOP VDOP Checksum 1. Satellite used in solution. $GPGSA A 3 07 02 1.8 1.0 1.5 *33 GSA protocol header See Table 5-6 See Table 5-7 Sv on Channel 1 Sv on Channel 2 .... Sv on Channel 12 Position Dilution of Precision Horizontal Dilution of Precision Vertical Dilution of Precision End of message termination Table 4-6 Mode 1 Value Description M A Value Manual--forced to operate in 2D or 3D mode 2DAutomatic--allowed to automatically switch 2D/3D Table 4-7 Mode 2 Description 1 2 3 Fix Not ...