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
Diff: GPS_parser.cpp
- Revision:
- 5:94daced1e61a
- Child:
- 6:4ed12067a314
diff -r 6e2d98b5cb86 -r 94daced1e61a GPS_parser.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/GPS_parser.cpp Wed Dec 12 17:32:31 2012 +0000 @@ -0,0 +1,243 @@ +#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; +} +