Campbell GPS16X-HVS, Product Manual

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GPS16X-HVS GPS Receiver
14
CRBasic Example 8-1. Reading the GPS Using the GPS() Instruction
'Program the GPS16-HVS to use 38.4 kbaud, no parity, 8 data bits, and 1 stop bit
PipeLineMode
Const LOCAL_TIME_OFFSET = -6 'Local time offset relative to UTC time
Dim nmea_sentence(2) As String * 100
Public gps_data(15)
Alias gps_data(1) = latitude_a 'Degrees latitude (+ = North; - = South)
Alias gps_data(2) = latitude_b 'Minutes latitude
Alias gps_data(3) = longitude_a 'Degress longitude (+ = East; - = West)
Alias gps_data(4) = longitude_b 'Minutes longitude
Alias gps_data(5) = speed 'Speed
Alias gps_data(6) = course 'Course over ground
Alias gps_data(7) = magnetic_variation 'Magnetic variation from true north (+ =
'East; - = West)
Alias gps_data(8) = fix_quality 'GPS fix quality: 0 = invalid, 1 = GPS, 2 =
'differential GPS, 6 = estimated
Alias gps_data(9) = nmbr_satellites 'Number of satellites used for fix
Alias gps_data(10) = altitude 'Antenna altitude
Alias gps_data(11) = pps 'usec into sec of system clock when PPS
'rising edge occurs, typically 990,000 once
'synced
Alias gps_data(12) = dt_since_gprmc 'Time since last GPRMC string, normally less
'than 1 second
Alias gps_data(13) = gps_ready 'Counts from 0 to 10, 10 = ready
Alias gps_data(14) = max_clock_change 'Maximum value the clock was changed in msec
Alias gps_data(15) = nmbr_clock_change 'Number of times the clock was changed
'Define Units to be used in data file header
Units latitude_a = degrees
Units latitude_b = minutes
Units longitude_a = degrees
Units longitude_b = minutes
Units speed = knots
Units course = degrees
Units magnetic_variation = unitless
Units fix_quality = unitless
Units nmbr_satellites = unitless
Units altitude = m
Units pps = ms
Units dt_since_gprmc = s
Units gps_ready = unitless
Units max_clock_change = ms
Units nmbr_clock_change = samples
BeginProg
'Use SetStatus prior to scan if baud rate needs to be changed for device
Scan (1,Sec,0,0)
GPS (latitude_a,Com4,LOCAL_TIME_OFFSET*3600,100,nmea_sentence(1))
NextScan
EndProg
9. Troubleshooting
Testing and evaluation of serial communications is best done by reducing the
whole system to small manageable systems. Usually some portions of the
whole system are working. The first steps involve finding what is working.
During this process, you may find parts of the system that are not working or
mistakes that can be easily corrected. Fix each subsystem before testing others.