Tyler Weaver / nmea_parser

nmea gps library - without any serial

Dependents:   HARP2 HARP3 20180621_FT813

Fork of GPS_parser by Tyler Weaver

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@5:94daced1e61a, 2012-12-12 (annotated)

Committer:
tylerjw
Date:
Wed Dec 12 17:32:31 2012 +0000
Revision:
5:94daced1e61a
Child:
6:4ed12067a314
bug fix

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tylerjw 5:94daced1e61a 1 #include "GPS_parser.h"
tylerjw 5:94daced1e61a 2
tylerjw 5:94daced1e61a 3 GPS_Parser::GPS_Parser()
tylerjw 5:94daced1e61a 4 {
tylerjw 5:94daced1e61a 5 nmea_longitude = 0.0;
tylerjw 5:94daced1e61a 6 nmea_latitude = 0.0;
tylerjw 5:94daced1e61a 7 utc_time = 0;
tylerjw 5:94daced1e61a 8 ns = ' ';
tylerjw 5:94daced1e61a 9 ew = ' ';
tylerjw 5:94daced1e61a 10 lock = 0;
tylerjw 5:94daced1e61a 11 satelites = 0;
tylerjw 5:94daced1e61a 12 hdop = 0.0;
tylerjw 5:94daced1e61a 13 msl_altitude = 0.0;
tylerjw 5:94daced1e61a 14 msl_units = ' ';
tylerjw 5:94daced1e61a 15
tylerjw 5:94daced1e61a 16 rmc_status = ' ';
tylerjw 5:94daced1e61a 17 speed_k = 0.0;
tylerjw 5:94daced1e61a 18 course_d = 0.0;
tylerjw 5:94daced1e61a 19 date = 0;
tylerjw 5:94daced1e61a 20
tylerjw 5:94daced1e61a 21 dec_longitude = 0.0;
tylerjw 5:94daced1e61a 22 dec_latitude = 0.0;
tylerjw 5:94daced1e61a 23
tylerjw 5:94daced1e61a 24 gll_status = ' ';
tylerjw 5:94daced1e61a 25
tylerjw 5:94daced1e61a 26 course_t = 0.0; // ground speed true
tylerjw 5:94daced1e61a 27 course_t_unit = ' ';
tylerjw 5:94daced1e61a 28 course_m = 0.0; // magnetic
tylerjw 5:94daced1e61a 29 course_m_unit = ' ';
tylerjw 5:94daced1e61a 30 speed_k_unit = ' ';
tylerjw 5:94daced1e61a 31 speed_km = 0.0; // speek km/hr
tylerjw 5:94daced1e61a 32 speed_km_unit = ' ';
tylerjw 5:94daced1e61a 33
tylerjw 5:94daced1e61a 34 altitude_ft = 0.0;
tylerjw 5:94daced1e61a 35 }
tylerjw 5:94daced1e61a 36
tylerjw 5:94daced1e61a 37 float GPS_Parser::nmea_to_dec(float deg_coord, char nsew)
tylerjw 5:94daced1e61a 38 {
tylerjw 5:94daced1e61a 39 int degree = (int)(deg_coord/100);
tylerjw 5:94daced1e61a 40 float minutes = deg_coord - degree*100;
tylerjw 5:94daced1e61a 41 float dec_deg = minutes / 60;
tylerjw 5:94daced1e61a 42 float decimal = degree + dec_deg;
tylerjw 5:94daced1e61a 43 if (nsew == 'S' || nsew == 'W') { // return negative
tylerjw 5:94daced1e61a 44 decimal *= -1;
tylerjw 5:94daced1e61a 45 }
tylerjw 5:94daced1e61a 46 return decimal;
tylerjw 5:94daced1e61a 47 }
tylerjw 5:94daced1e61a 48
tylerjw 5:94daced1e61a 49 int GPS_Parser::sample(char *msg)
tylerjw 5:94daced1e61a 50 {
tylerjw 5:94daced1e61a 51 int line_parsed = 0;
tylerjw 5:94daced1e61a 52
tylerjw 5:94daced1e61a 53 // Check if it is a GPGGA msg (matches both locked and non-locked msg)
tylerjw 5:94daced1e61a 54 if (sscanf(msg, "$GPGGA,%f,%f,%c,%f,%c,%d,%d,%f,%f,%c", &utc_time, &nmea_latitude, &ns, &nmea_longitude, &ew, &lock, &satelites, &hdop, &msl_altitude, &msl_units) >= 1) {
tylerjw 5:94daced1e61a 55 line_parsed = GGA;
tylerjw 5:94daced1e61a 56 }
tylerjw 5:94daced1e61a 57 // Check if it is a GPRMC msg
tylerjw 5:94daced1e61a 58 else if (sscanf(msg, "$GPRMC,%f,%f,%c,%f,%c,%f,%f,%d", &utc_time, &nmea_latitude, &ns, &nmea_longitude, &ew, &speed_k, &course_d, &date) >= 1) {
tylerjw 5:94daced1e61a 59 line_parsed = RMC;
tylerjw 5:94daced1e61a 60 }
tylerjw 5:94daced1e61a 61
tylerjw 5:94daced1e61a 62 if(satelites == 0) {
tylerjw 5:94daced1e61a 63 lock = 0;
tylerjw 5:94daced1e61a 64 }
tylerjw 5:94daced1e61a 65 if (!lock) {
tylerjw 5:94daced1e61a 66 return NO_LOCK;
tylerjw 5:94daced1e61a 67 } else if (line_parsed) {
tylerjw 5:94daced1e61a 68 return line_parsed;
tylerjw 5:94daced1e61a 69 } else {
tylerjw 5:94daced1e61a 70 return NOT_PARSED;
tylerjw 5:94daced1e61a 71 }
tylerjw 5:94daced1e61a 72 }
tylerjw 5:94daced1e61a 73
tylerjw 5:94daced1e61a 74
tylerjw 5:94daced1e61a 75 // INTERNAL FUNCTINS ////////////////////////////////////////////////////////////
tylerjw 5:94daced1e61a 76 float GPS_Parser::trunc(float v)
tylerjw 5:94daced1e61a 77 {
tylerjw 5:94daced1e61a 78 if (v < 0.0) {
tylerjw 5:94daced1e61a 79 v*= -1.0;
tylerjw 5:94daced1e61a 80 v = floor(v);
tylerjw 5:94daced1e61a 81 v*=-1.0;
tylerjw 5:94daced1e61a 82 } else {
tylerjw 5:94daced1e61a 83 v = floor(v);
tylerjw 5:94daced1e61a 84 }
tylerjw 5:94daced1e61a 85 return v;
tylerjw 5:94daced1e61a 86 }
tylerjw 5:94daced1e61a 87
tylerjw 5:94daced1e61a 88 // GET FUNCTIONS /////////////////////////////////////////////////////////////////
tylerjw 5:94daced1e61a 89 float GPS_Parser::get_msl_altitude()
tylerjw 5:94daced1e61a 90 {
tylerjw 5:94daced1e61a 91 if (!lock)
tylerjw 5:94daced1e61a 92 return 0.0;
tylerjw 5:94daced1e61a 93 else
tylerjw 5:94daced1e61a 94 return msl_altitude;
tylerjw 5:94daced1e61a 95 }
tylerjw 5:94daced1e61a 96
tylerjw 5:94daced1e61a 97 int GPS_Parser::get_satelites()
tylerjw 5:94daced1e61a 98 {
tylerjw 5:94daced1e61a 99 if (!lock)
tylerjw 5:94daced1e61a 100 return 0;
tylerjw 5:94daced1e61a 101 else
tylerjw 5:94daced1e61a 102 return satelites;
tylerjw 5:94daced1e61a 103 }
tylerjw 5:94daced1e61a 104
tylerjw 5:94daced1e61a 105 float GPS_Parser::get_nmea_longitude()
tylerjw 5:94daced1e61a 106 {
tylerjw 5:94daced1e61a 107 if (!lock)
tylerjw 5:94daced1e61a 108 return 0.0;
tylerjw 5:94daced1e61a 109 else
tylerjw 5:94daced1e61a 110 return nmea_longitude;
tylerjw 5:94daced1e61a 111 }
tylerjw 5:94daced1e61a 112
tylerjw 5:94daced1e61a 113 float GPS_Parser::get_dec_longitude()
tylerjw 5:94daced1e61a 114 {
tylerjw 5:94daced1e61a 115 dec_longitude = nmea_to_dec(nmea_longitude, ew);
tylerjw 5:94daced1e61a 116 if (!lock)
tylerjw 5:94daced1e61a 117 return 0.0;
tylerjw 5:94daced1e61a 118 else
tylerjw 5:94daced1e61a 119 return dec_longitude;
tylerjw 5:94daced1e61a 120 }
tylerjw 5:94daced1e61a 121
tylerjw 5:94daced1e61a 122 float GPS_Parser::get_nmea_latitude()
tylerjw 5:94daced1e61a 123 {
tylerjw 5:94daced1e61a 124 if (!lock)
tylerjw 5:94daced1e61a 125 return 0.0;
tylerjw 5:94daced1e61a 126 else
tylerjw 5:94daced1e61a 127 return nmea_latitude;
tylerjw 5:94daced1e61a 128 }
tylerjw 5:94daced1e61a 129
tylerjw 5:94daced1e61a 130 float GPS_Parser::get_dec_latitude()
tylerjw 5:94daced1e61a 131 {
tylerjw 5:94daced1e61a 132 dec_latitude = nmea_to_dec(nmea_latitude, ns);
tylerjw 5:94daced1e61a 133 if (!lock)
tylerjw 5:94daced1e61a 134 return 0.0;
tylerjw 5:94daced1e61a 135 else
tylerjw 5:94daced1e61a 136 return dec_latitude;
tylerjw 5:94daced1e61a 137 }
tylerjw 5:94daced1e61a 138
tylerjw 5:94daced1e61a 139 float GPS_Parser::get_course_t()
tylerjw 5:94daced1e61a 140 {
tylerjw 5:94daced1e61a 141 if (!lock)
tylerjw 5:94daced1e61a 142 return 0.0;
tylerjw 5:94daced1e61a 143 else
tylerjw 5:94daced1e61a 144 return course_t;
tylerjw 5:94daced1e61a 145 }
tylerjw 5:94daced1e61a 146
tylerjw 5:94daced1e61a 147 float GPS_Parser::get_course_m()
tylerjw 5:94daced1e61a 148 {
tylerjw 5:94daced1e61a 149 if (!lock)
tylerjw 5:94daced1e61a 150 return 0.0;
tylerjw 5:94daced1e61a 151 else
tylerjw 5:94daced1e61a 152 return course_m;
tylerjw 5:94daced1e61a 153 }
tylerjw 5:94daced1e61a 154
tylerjw 5:94daced1e61a 155 float GPS_Parser::get_speed_k()
tylerjw 5:94daced1e61a 156 {
tylerjw 5:94daced1e61a 157 if (!lock)
tylerjw 5:94daced1e61a 158 return 0.0;
tylerjw 5:94daced1e61a 159 else
tylerjw 5:94daced1e61a 160 return speed_k;
tylerjw 5:94daced1e61a 161 }
tylerjw 5:94daced1e61a 162
tylerjw 5:94daced1e61a 163 float GPS_Parser::get_speed_km()
tylerjw 5:94daced1e61a 164 {
tylerjw 5:94daced1e61a 165 if (!lock)
tylerjw 5:94daced1e61a 166 return 0.0;
tylerjw 5:94daced1e61a 167 else
tylerjw 5:94daced1e61a 168 return speed_km;
tylerjw 5:94daced1e61a 169 }
tylerjw 5:94daced1e61a 170
tylerjw 5:94daced1e61a 171 float GPS_Parser::get_altitude_ft()
tylerjw 5:94daced1e61a 172 {
tylerjw 5:94daced1e61a 173 if (!lock)
tylerjw 5:94daced1e61a 174 return 0.0;
tylerjw 5:94daced1e61a 175 else
tylerjw 5:94daced1e61a 176 return 3.280839895*msl_altitude;
tylerjw 5:94daced1e61a 177 }
tylerjw 5:94daced1e61a 178
tylerjw 5:94daced1e61a 179 // NAVIGATION FUNCTIONS ////////////////////////////////////////////////////////////
tylerjw 5:94daced1e61a 180 float GPS_Parser::calc_course_to(float pointLat, float pontLong)
tylerjw 5:94daced1e61a 181 {
tylerjw 5:94daced1e61a 182 const double d2r = PI / 180.0;
tylerjw 5:94daced1e61a 183 const double r2d = 180.0 / PI;
tylerjw 5:94daced1e61a 184 double dlat = abs(pointLat - get_dec_latitude()) * d2r;
tylerjw 5:94daced1e61a 185 double dlong = abs(pontLong - get_dec_longitude()) * d2r;
tylerjw 5:94daced1e61a 186 double y = sin(dlong) * cos(pointLat * d2r);
tylerjw 5:94daced1e61a 187 double x = cos(get_dec_latitude()*d2r)*sin(pointLat*d2r) - sin(get_dec_latitude()*d2r)*cos(pointLat*d2r)*cos(dlong);
tylerjw 5:94daced1e61a 188 return 360.0-(atan2(y,x)*r2d);
tylerjw 5:94daced1e61a 189 }
tylerjw 5:94daced1e61a 190
tylerjw 5:94daced1e61a 191 /*
tylerjw 5:94daced1e61a 192 var y = Math.sin(dLon) * Math.cos(lat2);
tylerjw 5:94daced1e61a 193 var x = Math.cos(lat1)*Math.sin(lat2) -
tylerjw 5:94daced1e61a 194 Math.sin(lat1)*Math.cos(lat2)*Math.cos(dLon);
tylerjw 5:94daced1e61a 195 var brng = Math.atan2(y, x).toDeg();
tylerjw 5:94daced1e61a 196 */
tylerjw 5:94daced1e61a 197
tylerjw 5:94daced1e61a 198 /*
tylerjw 5:94daced1e61a 199 The Haversine formula according to Dr. Math.
tylerjw 5:94daced1e61a 200 http://mathforum.org/library/drmath/view/51879.html
tylerjw 5:94daced1e61a 201
tylerjw 5:94daced1e61a 202 dlon = lon2 - lon1
tylerjw 5:94daced1e61a 203 dlat = lat2 - lat1
tylerjw 5:94daced1e61a 204 a = (sin(dlat/2))^2 + cos(lat1) * cos(lat2) * (sin(dlon/2))^2
tylerjw 5:94daced1e61a 205 c = 2 * atan2(sqrt(a), sqrt(1-a))
tylerjw 5:94daced1e61a 206 d = R * c
tylerjw 5:94daced1e61a 207
tylerjw 5:94daced1e61a 208 Where
tylerjw 5:94daced1e61a 209 * dlon is the change in longitude
tylerjw 5:94daced1e61a 210 * dlat is the change in latitude
tylerjw 5:94daced1e61a 211 * c is the great circle distance in Radians.
tylerjw 5:94daced1e61a 212 * R is the radius of a spherical Earth.
tylerjw 5:94daced1e61a 213 * The locations of the two points in
tylerjw 5:94daced1e61a 214 spherical coordinates (longitude and
tylerjw 5:94daced1e61a 215 latitude) are lon1,lat1 and lon2, lat2.
tylerjw 5:94daced1e61a 216 */
tylerjw 5:94daced1e61a 217 double GPS_Parser::calc_dist_to_mi(float pointLat, float pontLong)
tylerjw 5:94daced1e61a 218 {
tylerjw 5:94daced1e61a 219 const double d2r = PI / 180.0;
tylerjw 5:94daced1e61a 220 double dlat = pointLat - get_dec_latitude();
tylerjw 5:94daced1e61a 221 double dlong = pontLong - get_dec_longitude();
tylerjw 5:94daced1e61a 222 double a = pow(sin(dlat/2.0),2.0) + cos(get_dec_latitude()*d2r) * cos(pointLat*d2r) * pow(sin(dlong/2.0),2.0);
tylerjw 5:94daced1e61a 223 double c = 2.0 * asin(sqrt(abs(a)));
tylerjw 5:94daced1e61a 224 double d = 63.765 * c;
tylerjw 5:94daced1e61a 225
tylerjw 5:94daced1e61a 226 return d;
tylerjw 5:94daced1e61a 227 }
tylerjw 5:94daced1e61a 228
tylerjw 5:94daced1e61a 229 double GPS_Parser::calc_dist_to_ft(float pointLat, float pontLong)
tylerjw 5:94daced1e61a 230 {
tylerjw 5:94daced1e61a 231 return calc_dist_to_mi(pointLat, pontLong)*5280.0;
tylerjw 5:94daced1e61a 232 }
tylerjw 5:94daced1e61a 233
tylerjw 5:94daced1e61a 234 double GPS_Parser::calc_dist_to_km(float pointLat, float pontLong)
tylerjw 5:94daced1e61a 235 {
tylerjw 5:94daced1e61a 236 return calc_dist_to_mi(pointLat, pontLong)*1.609344;
tylerjw 5:94daced1e61a 237 }
tylerjw 5:94daced1e61a 238
tylerjw 5:94daced1e61a 239 double GPS_Parser::calc_dist_to_m(float pointLat, float pontLong)
tylerjw 5:94daced1e61a 240 {
tylerjw 5:94daced1e61a 241 return calc_dist_to_mi(pointLat, pontLong)*1609.344;
tylerjw 5:94daced1e61a 242 }
tylerjw 5:94daced1e61a 243