Garmin GPS 16HVS - Receiver Module Instruction Manual

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Garmin GPS 16HVS - Receiver Module Instruction Manual Manual pdf 9 page image

Garmin 16-HVS GPS ReceiverWarm StartOne satellite in use, time from GPS Real Time Clock (not GPS), no position:$GPGGA,183806.0,,,,,0,01,,,,,,,*7DValid GPS FixThree satellites acquired, time and position valid:$GPGGA,005322.0,4147.603,N,11150.978,W,1,03,11.9,00016,M,-016,M,,*6EIf the almanac and ephemeris data are not stored in the non-volatile data, GPSacquisition time is less than 5 minutes. If only the ephemeris data areunknown, acquisition time is less than 45 seconds. If all data are known(warm start), GPS acquisition time is less than 15 seconds.4. CRBasic ProgrammingCRBasic is used to write programs for the CR1000, CR3000, CR800, andCR850 dataloggers. These dataloggers use several instructions to read GPSoutput, which is asynchronous serial data. As shipped from CampbellScientific, the GPS receiver will output data once a second, 1200 baud, 8 databits, no parity, and 1 stop bit. Only the GPGGA string is output. See Section3 for details on the GPGGA string. See Appendix D for specifics on changingthe GPS receiver setups, including using higher baud rates, which the CR1000,CR3000, CR800, and CR850 support.4.1 Read GPS Data4.1.1 SerialOpenSerialOpen is used to open the appropriate serial port, specify the baud rate,data format, etc. Any of the six serial ports may be used, but option codes 3, 4and 5 are not used in this application. Data format is zero, TX delay is zero,buffer size should be about 2000, which is large enough to prevent theGPGGA string from overrunning the buffer before data is read by the SerialIninstruction. If memory is limited, the buffer size can be smaller.Example: SerialOpen (com1,1200,0,0,2000)4.1.2 SerialInThe SerialIn instruction removes data from the buffer declared in theSerialOpen instruction and places the data in a variable of type string. Use atimeout of 20, a termination character of 13, and maximum number ofcharacters of 100, or 1 less than the size of the destination variable. Declare astring variable of size 101 before using SerialIn.Example: Public GPSdata as string * 101Example: SerialIn (GPSData,com1,20,13,100)4.1.3 SerialFlushThe SerialFlush instruction is used to clear all data from the buffer associatedwith the serial port.5