nmea gps library - without any serial
Dependents: HARP2 HARP3 20180621_FT813
Fork of GPS_parser by
NMEA GPS Serial Output parser.
Routine taken from NMEA Software Standard (NMEA 0183) http://www.winsystems.com/software/nmea.pdf
Only handles GGA and RMC Messages
GPS_parser.cpp
- Committer:
- tylerjw
- Date:
- 2012-12-12
- Revision:
- 6:4ed12067a314
- Parent:
- 5:94daced1e61a
- Child:
- 7:01a8379370e4
File content as of revision 6:4ed12067a314:
#include "GPS_parser.h" GPS_Parser::GPS_Parser() { 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; } float GPS_Parser::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_Parser::sample(char *msg) { int line_parsed = 0; // 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,%f,%c,%f,%c,%f,%f,%d", &utc_time, &nmea_latitude, &ns, &nmea_longitude, &ew, &speed_k, &course_d, &date) >= 1) { line_parsed = RMC; } 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_Parser::trunc(float v) { if (v < 0.0) { v*= -1.0; v = floor(v); v*=-1.0; } else { v = floor(v); } return v; } // GET FUNCTIONS ///////////////////////////////////////////////////////////////// float GPS_Parser::get_msl_altitude() { if (!lock) return 0.0; else return msl_altitude; } int GPS_Parser::get_satelites() { if (!lock) return 0; else return satelites; } float GPS_Parser::get_nmea_longitude() { if (!lock) return 0.0; else return nmea_longitude; } float GPS_Parser::get_dec_longitude() { dec_longitude = nmea_to_dec(nmea_longitude, ew); if (!lock) return 0.0; else return dec_longitude; } float GPS_Parser::get_nmea_latitude() { if (!lock) return 0.0; else return nmea_latitude; } float GPS_Parser::get_dec_latitude() { dec_latitude = nmea_to_dec(nmea_latitude, ns); if (!lock) return 0.0; else return dec_latitude; } float GPS_Parser::get_course_t() { if (!lock) return 0.0; else return course_t; } float GPS_Parser::get_course_m() { if (!lock) return 0.0; else return course_m; } float GPS_Parser::get_speed_k() { if (!lock) return 0.0; else return speed_k; } float GPS_Parser::get_speed_km() { if (!lock) return 0.0; else return speed_km; } float GPS_Parser::get_altitude_ft() { if (!lock) return 0.0; else return 3.280839895*msl_altitude; } // NAVIGATION FUNCTIONS //////////////////////////////////////////////////////////// float GPS_Parser::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 360.0-(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_Parser::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_Parser::calc_dist_to_ft(float pointLat, float pontLong) { return calc_dist_to_mi(pointLat, pontLong)*5280.0; } double GPS_Parser::calc_dist_to_km(float pointLat, float pontLong) { return calc_dist_to_mi(pointLat, pontLong)*1.609344; } double GPS_Parser::calc_dist_to_m(float pointLat, float pontLong) { return calc_dist_to_mi(pointLat, pontLong)*1609.344; }