File content as of revision 1:2ace7946a246:

#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() {
    int line_parsed = 0;

    if (_gps.readable()) {
        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) {
            line_parsed = 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) {
            line_parsed = 1;
        }
        if (!lock) {
            return NO_LOCK;
        } else if (line_parsed) {
            return PARSED;
        } else {
            return NOT_PARSED;
        }
    } else {
        return NO_MSG;
    }
}

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() {
    dec_longitude = nmea_to_dec(nmea_longitude, ew);
    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() {
    dec_latitude = nmea_to_dec(nmea_latitude, ns);
    if (!lock)
        return 0.0;
    else
        return nmea_latitude;
}