Generation 3 of the Harp project
Dependencies: Servo TMP36 GZ buffered-serial1 chan_fatfs_sd nmea_parser watchdog mbed-rtos mbed
Fork of HARP2 by
GPS/GPS.cpp
- Committer:
- tylerjw
- Date:
- 2012-02-22
- Revision:
- 0:ce5f06c3895f
- Child:
- 1:2ace7946a246
File content as of revision 0:ce5f06c3895f:
#include "GPS.h" GPS::GPS(PinName tx, PinName rx) : _gps(tx, rx) { _gps.baud(4800); nmea_longitude = 0.0; nmea_latitude = 0.0; utc_time = 0; ns = ' '; ew = ' '; lock = 0; satelites = 0; hdop = 0.0; msl_altitude = 0.0; msl_units = ' '; rmc_status = ' '; ground_speed_k = 0.0; ground_course_d = 0.0; date = 0; dec_longitude = 0.0; dec_latitude = 0.0; } float GPS::nmea_to_dec(float deg_coord, char nsew) { int degree = (int)(deg_coord/100); float minutes = deg_coord - degree*100; float dec_deg = minutes / 60; float decimal = degree + dec_deg; if(nsew == 'S' || nsew == 'W') // return negative { decimal *= -1; } return decimal; } int GPS::sample() { while(1) { getline(); // Check if it is a GPGGA msg (matches both locked and non-locked msg) if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d,%d,%f,%f,%c", &utc_time, &nmea_latitude, &ns, &nmea_longitude, &ew, &lock, &satelites, &hdop, &msl_altitude, &msl_units) >= 1) { if(!lock) { return 0; } else { dec_latitude = nmea_to_dec(nmea_latitude, ns); dec_longitude = nmea_to_dec(nmea_longitude, ew); return 1; } } // Check if it is a GPRMC msg) else if(sscanf(msg, "GPRMC,%f,%c,%f,%c,%f,%c,%f,%f,%d", &utc_time, &rmc_status, &nmea_latitude, &ns, &nmea_longitude, &ew, &ground_speed_k, &ground_course_d, &date) >= 1) { if(!lock) { return 0; } else { dec_latitude = nmea_to_dec(nmea_latitude, ns); dec_longitude = nmea_to_dec(nmea_longitude, ew); return 1; } } } } float GPS::trunc(float v) { if(v < 0.0) { v*= -1.0; v = floor(v); v*=-1.0; } else { v = floor(v); } return v; } void GPS::getline() { while(_gps.getc() != '$'); // wait for the start of a line for(int i=0; i<256; i++) { msg[i] = _gps.getc(); if(msg[i] == '\r') { msg[i] = 0; return; } } error("Overflowed message limit"); } float GPS::get_msl_altitude() { if(!lock) return 0.0; else return msl_altitude; } int GPS::get_satelites() { if(!lock) return 0; else return satelites; } float GPS::get_nmea_longitude() { if(!lock) return 0.0; else return nmea_longitude; } float GPS::get_dec_longitude() { if(!lock) return 0.0; else return dec_longitude; } float GPS::get_nmea_latitude() { if(!lock) return 0.0; else return nmea_latitude; } float GPS::get_dec_latitude() { if(!lock) return 0.0; else return nmea_latitude; }