asd
Fork of GPS by
GPS.cpp
- Committer:
- tylerjw
- Date:
- 2012-07-17
- Revision:
- 0:3611af72bfd7
- Child:
- 2:24e0699d784f
File content as of revision 0:3611af72bfd7:
#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 = ' '; speed_k = 0.0; course_d = 0.0; date = 0; dec_longitude = 0.0; dec_latitude = 0.0; gll_status = ' '; course_t = 0.0; // ground speed true course_t_unit = ' '; course_m = 0.0; // magnetic course_m_unit = ' '; speed_k_unit = ' '; speed_km = 0.0; // speek km/hr speed_km_unit = ' '; altitude_ft = 0.0; #ifdef OPEN_LOG is_logging = false; #endif } #ifdef OPEN_LOG void GPS::start_log() { is_logging = true; } void GPS::new_file(void) { _openLog.newFile(); } void GPS::stop_log(void) { is_logging = false; } #endif 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(); #ifdef OPEN_LOG if (is_logging && lock) { format_for_log(); _openLog.write(bfr); } #endif // 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 = GGA; } // Check if it is a GPRMC msg else if (sscanf(msg, "GPRMC,%f,%c,%f,%c,%f,%f,%d", &utc_time, &ns, &nmea_longitude, &ew, &speed_k, &course_d, &date) >= 1) { line_parsed = RMC; } // GLL - Geographic Position-Lat/Lon else if (sscanf(msg, "GPGLL,%f,%c,%f,%c,%f,%c", &nmea_latitude, &ns, &nmea_longitude, &ew, &utc_time, &gll_status) >= 1) { line_parsed = GLL; } // VTG-Course Over Ground and Ground Speed else if (sscanf(msg, "GPVTG,%f,%c,%f,%c,%f,%c,%f,%c", &course_t, &course_t_unit, &course_m, &course_m_unit, &speed_k, &speed_k_unit, &speed_km, &speed_km_unit) >= 1) { line_parsed = VTG; } if(satelites == 0) { lock = 0; } } if (!lock) { return NO_LOCK; } else if (line_parsed) { return line_parsed; } else { return NOT_PARSED; } } // INTERNAL FUNCTINS //////////////////////////////////////////////////////////// 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() != '$'); // wait for the start of a line for (int i=0; i<1022; i++) { msg[i] = _gps.getc(); if (msg[i] == '\r') { msg[i] = 0; return; } } error("Overflow in getline"); } void GPS::format_for_log() { bfr[0] = '$'; for (int i = 0; i < 1022; i++) { bfr[i+1] = msg[i]; if (msg[i] == 0 || msg[i] =='$') { bfr[i+1] = '\r'; bfr[i+2] = '\n'; bfr[i+3] = 0; return; } } error("Overflow in format"); } // GET FUNCTIONS ///////////////////////////////////////////////////////////////// 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 dec_latitude; } float GPS::get_course_t() { if (!lock) return 0.0; else return course_t; } float GPS::get_course_m() { if (!lock) return 0.0; else return course_m; } float GPS::get_speed_k() { if (!lock) return 0.0; else return speed_k; } float GPS::get_speed_km() { if (!lock) return 0.0; else return speed_km; } float GPS::get_altitude_ft() { if (!lock) return 0.0; else return 3.280839895*msl_altitude; } // NAVIGATION FUNCTIONS //////////////////////////////////////////////////////////// float GPS::calc_course_to(float pointLat, float pontLong) { const double d2r = PI / 180.0; const double r2d = 180.0 / PI; double dlat = abs(pointLat - get_dec_latitude()) * d2r; double dlong = abs(pontLong - get_dec_longitude()) * d2r; double y = sin(dlong) * cos(pointLat * d2r); double x = cos(get_dec_latitude()*d2r)*sin(pointLat*d2r) - sin(get_dec_latitude()*d2r)*cos(pointLat*d2r)*cos(dlong); return atan2(y,x)*r2d; } /* var y = Math.sin(dLon) * Math.cos(lat2); var x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(dLon); var brng = Math.atan2(y, x).toDeg(); */ /* The Haversine formula according to Dr. Math. http://mathforum.org/library/drmath/view/51879.html dlon = lon2 - lon1 dlat = lat2 - lat1 a = (sin(dlat/2))^2 + cos(lat1) * cos(lat2) * (sin(dlon/2))^2 c = 2 * atan2(sqrt(a), sqrt(1-a)) d = R * c Where * dlon is the change in longitude * dlat is the change in latitude * c is the great circle distance in Radians. * R is the radius of a spherical Earth. * The locations of the two points in spherical coordinates (longitude and latitude) are lon1,lat1 and lon2, lat2. */ double GPS::calc_dist_to_mi(float pointLat, float pontLong) { const double d2r = PI / 180.0; double dlat = pointLat - get_dec_latitude(); double dlong = pontLong - get_dec_longitude(); double a = pow(sin(dlat/2.0),2.0) + cos(get_dec_latitude()*d2r) * cos(pointLat*d2r) * pow(sin(dlong/2.0),2.0); double c = 2.0 * asin(sqrt(abs(a))); double d = 63.765 * c; return d; } double GPS::calc_dist_to_ft(float pointLat, float pontLong) { return calc_dist_to_mi(pointLat, pontLong)*5280.0; } double GPS::calc_dist_to_km(float pointLat, float pontLong) { return calc_dist_to_mi(pointLat, pontLong)*1.609344; } double GPS::calc_dist_to_m(float pointLat, float pontLong) { return calc_dist_to_mi(pointLat, pontLong)*1609.344; }