User manual HAICOM USB GPS RECEIVER

[. . . ] The receiver uses this information to calculate its position. 2 Although GPS was designed for military use, many thousands of civilians make use of it. The satellites actually broadcast two signals, one is only for military use, and the other can be used by both military and civilians. Since GPS is passive (you only need to receive the signal), there are no restrictions on who can use the signal available to civilians. GPS technology can be used in a variety of fields besides providing navigation for vehicles on the sea, in the air and on the ground. [. . . ] Accuracy of the one-pulse-per-second output is maintained only when the GPS receiver has valid position fix. The 1PPS output is always generated when the GPS receiver is powered-on. Proper adjustment of the 1PPS output to align with the GPS second requires calculation of the receiver clock offset and clock drift-rate as part of the position-velocity-time (PVT) solution. When enough satellite signals are received to generate valid position fixes, the 1PPS output is adjusted to align with the GPS second in several seconds. When the 1PPS output is brought in sync with the GPS second, the 1PPS Valid Signal on the I/O pin becomes active (HIGH); when the 1PPS output is not yet in sync with the GPS second, the 1PPS Valid Signal remains inactive (LOW). 13 As long as enough satellite signals are received to generate valid position fixes, the 1PPS output remains synchronized to the GPS second, and the 1PPS Valid Signal remains active. If signal blockage prevents the receiver from generating valid position fix, the 1PPS output will drift away from the GPS second and the 1PPS Valid Signal will become inactive. Upon re-acquiring enough satellites to generate consecutive valid position fixes, the 1PPS Valid Signal will become active again, signaling that the 1PPS output is again synchronized with the GPS second. For best stable operation of the 1PPS signal, it is to be operated in static environment having clear view of the sky. 14 SECTION 4 SOFTWARE INTERFACE This section describes the details of the serial port commands through which the HI-204III-USB is controlled and monitored. The serial port commands allow users to set the receiver parameters, configure output message type, and retrieve status information. The baud rate and protocol of the host COM port must match the baud rate and protocol of the GPS receiver serial port for commands and data to be successfully transmitted and received. The default receiver protocol is 4800 bps, 8 data bits, 1 stop bit, and none parity. 4. 1 NMEA OUTPUT MESSAGE SPECIFICATION The HI-204III-USB supports NMEA-0183 output format as defined by the National Marine Electronics Association (http://www. nmea. org). The currently supported NMEA messages for GPS applications are: GGA Global Positioning System Fix Data GLL Geographic Position Latitude / Longitude GSA GNSS DOP and Active Satellites GSV GNSS Satellites in View RMC Recommended Minimum Specific GNSS Data VTG Course Over Ground and Ground Speed 15 4. 1. 1 NMEA Messages The serial interface protocol is based on the National Marine Electronics Association's NMEA 0183 ASCII interface specification. This standard is fully define in "NMEA 0183, Version 3. 01" The standard may be obtained from NMEA, www. nmea. org 4. 1. 2 GGA - GPS FIX DATA Time, position and position-fix related data (number of satellites in use, HDOP, etc. ). Format: $GPGGA, <1>, <2>, <3>, <4>, <5>, <6>, <7>, <8>, <9>, M, <10>, M, <11>, <12>, *<13><CR><LF> Example: $GPGGA, 104549. 04, 2447. 2038, N, 12100. 4990, E, 1, 06, 01. 7, 00078. 8, M, 0016. 3, M, , *5C<CR><LF> 16 Field Example Description 1 104549. 04 UTC time in hhmmss. ss format, 000000. 00 ~ 235959. 99 2 2447. 2038 Latitude in ddmm. mmmm format Leading zeros transmitted 3 N Latitude hemisphere indicator, 'N' = North, 'S' = South 4 12100. 4990 Longitude in dddmm. mmmm format Leading zeros transmitted 5 E Longitude hemisphere indicator, 'E' = East, 'W' = West 6 1 Position fix quality indicator 0: position fix unavailable 1: valid position fix, SPS mode 2: valid position fix, differential GPS mode 7 06 Number of satellites in use, 00 ~ 12 8 01. 7 Horizontal dilution of precision, 00. 0 ~ 99. 9 9 00078. 8 Antenna height above/below mean sea level, -9999. 9 ~ 17999. 9 10 0016. 3 Geoidal height, -999. 9 ~ 9999. 9 11 Age of DGPS data since last valid RTCM transmission in xxx format (seconds) NULL when DGPS not used 12 Differential reference station ID, 0000 ~ 1023 NULL when DGPS not used 13 5C Checksum Note: The checksum field starts with a '*' and consists of 2 characters representing a hex number. The checksum is the exclusive OR of all characters between '$' and '*'. 17 4. 1. 3 GLL - LATITUDE AND LONGITUDE, WITH TIME OF POSITION FIX AND STATUS Latitude and longitude of current position, time, and status. Format: $GPRMC, <1>, <2>, <3>, <4>, <5>, <6>, <7>, <8>, <9>, <10>, <11>, <12>*<13><CR><LF> Example: $GPRMC, 104549. 04, A, 2447. 2038, N, 12100. 4990, E, 016. 0, 221. 0, 250304, 003. 3, W, A*22<CR><LF> 23 Field Example Description 1 104549. 04 UTC time in hhmmss. ss format, 000000. 00 ~ 235959. 99 2 A Status, 'V' = navigation receiver warning, 'A' = valid position 3 2447. 2038 Latitude in dddmm. mmmm format Leading zeros transmitted 4 N Latitude hemisphere indicator, 'N' = North, 'S' = South 5 12100. 4990 Longitude in dddmm. mmmm format Leading zeros transmitted 6 E Longitude hemisphere indicator, 'E' = East, 'W' = West 7 016. 0 Speed over ground, 000. 0 ~ 999. 9 knots 8 221. 0 Course over ground, 000. 0 ~ 359. 9 degrees 9 250304 UTC date of position fix, ddmmyy format 10 003. 3 Magnetic variation, 000. 0 ~ 180. 0 degrees 11 W Magnetic variation direction, 'E' = East, 'W' = West 12 A Mode indicator 'N' = Data invalid 'D' = Differential 'A' = Autonomous 'E' = Estimated 13 22 Checksum 24 4. 1. 7 VTG - COURSE OVER GROUND AND GROUND SPEED Velocity is given as course over ground (COG) and speed over ground (SOG). Format: GPVTG, <1>, T, <2>, M, <3>, N, <4>, K, <5>*<6><CR><LF> Example: $GPVTG, 221. 0, T, 224. 3, M, 016. 0, N, 0029. 6, K, A*1F<CR><LF> Field 1 2 3 4 5 Example 221. 0 224. 3 016. 0 0029. 6 A Description True course over ground, 000. 0 ~ 359. 9 degrees Magnetic course over ground, 000. 0 ~ 359. 9 degrees Speed over ground, 000. 0 ~ 999. 9 knots Speed over ground, 0000. 0 ~ 1800. 0 kilometers per hour Mode indicator 'N' = Data invalid 'A' = Autonomous 6 1F Checksum 'D' = Differential 'E' = Estimated 25 APPENDIX B DEFAULT VALUES The product has the following factory preset default values: Datum: NMEA Enable Switch: 000 (WGS-84) GGA ON ( 1 sec. output) Checksum ON Baud Rate: Elevation Mask: DOP Mask: 4800 Baud 5 degrees DOP Select: Auto GDOP: 10 PDOP: 10 HDOP: 10 Receiver Operating Mode: Normal Mode (without 1PPS) Commands can be issued to the HI-204III to change the settings of the receiver. The new settings will remain effective on next power-on as long as the on-board rechargeable backup battery is not discharged. After the backup battery is discharged, factory preset default settings will be used. 26 TROUBLESHOOTING Problem No Position output but timer is counting Reasons Weak or no GPS signal can be received at the place of HI-204III-USB unit At outdoor space but GPS signal is blocked by building or car roof To try again, go to outdoor and press 'Reset' or connect external antenna on the side of HI-204III-USB to improve the poor GPS signal Can's open COM port The PS/II connector did not insert correctly or some other application is the COM port Can not find HI-204III-USB No signal Poor connection No action for few minites may causes PocketPC into the power saving mode. Weak or no GPS signal when using HI-204III-USB indoor or inside the car. Put HI-204III-USB to an open space or car roof, then, press the Reset button Check HI-204III-USB if Plug firmly Close all applications and exacute it again to re-open the COM port Plug HI-204III-USB connector firmly or close all other application that occupied the COM port Solutions Place the HI-204III-USB under an open space, then, press 'Reset' 27 USB Driver Setup Guide HI-204III-USB USB GPS Receiver 28 A. [. . . ] If your system is Windows 2000, please refer to Windows XP installation guide. 2. If you follow the steps but the GPS receiver doesn't work, please try to unplug the GPS receiver from the USB port, wait for 5~8 seconds, and re-plug the GPS receiver into your PC. 3. Occasionally the mouse cursor does not work properly when you run the Win2000 and Win XP, and this situation is owing to Win2000 and Win XP operating system instead of the GPS receiver. Microsoft announces that this situation is "the serial device may be detected as a serial mouse in Win2000 and Win XP". 60 4. 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