nmea gps library - without any serial
Fork of GPS by
GPS_parser.cpp@7:01a8379370e4, 2012-12-13 (annotated)
- Committer:
- tylerjw
- Date:
- Thu Dec 13 04:57:10 2012 +0000
- Revision:
- 7:01a8379370e4
- Parent:
- 6:4ed12067a314
- Child:
- 8:59acef1c795b
tokenizer replaces sscanf :)
Who changed what in which revision?
User | Revision | Line number | New 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 | 7:01a8379370e4 | 11 | satellites = 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 | 7:01a8379370e4 | 24 | altitude_ft = 0.0; |
tylerjw | 5:94daced1e61a | 25 | |
tylerjw | 7:01a8379370e4 | 26 | current = NULL; |
tylerjw | 5:94daced1e61a | 27 | } |
tylerjw | 5:94daced1e61a | 28 | |
tylerjw | 5:94daced1e61a | 29 | float GPS_Parser::nmea_to_dec(float deg_coord, char nsew) |
tylerjw | 5:94daced1e61a | 30 | { |
tylerjw | 5:94daced1e61a | 31 | int degree = (int)(deg_coord/100); |
tylerjw | 5:94daced1e61a | 32 | float minutes = deg_coord - degree*100; |
tylerjw | 5:94daced1e61a | 33 | float dec_deg = minutes / 60; |
tylerjw | 5:94daced1e61a | 34 | float decimal = degree + dec_deg; |
tylerjw | 5:94daced1e61a | 35 | if (nsew == 'S' || nsew == 'W') { // return negative |
tylerjw | 5:94daced1e61a | 36 | decimal *= -1; |
tylerjw | 5:94daced1e61a | 37 | } |
tylerjw | 5:94daced1e61a | 38 | return decimal; |
tylerjw | 5:94daced1e61a | 39 | } |
tylerjw | 5:94daced1e61a | 40 | |
tylerjw | 5:94daced1e61a | 41 | |
tylerjw | 5:94daced1e61a | 42 | // INTERNAL FUNCTINS //////////////////////////////////////////////////////////// |
tylerjw | 5:94daced1e61a | 43 | float GPS_Parser::trunc(float v) |
tylerjw | 5:94daced1e61a | 44 | { |
tylerjw | 5:94daced1e61a | 45 | if (v < 0.0) { |
tylerjw | 5:94daced1e61a | 46 | v*= -1.0; |
tylerjw | 5:94daced1e61a | 47 | v = floor(v); |
tylerjw | 5:94daced1e61a | 48 | v*=-1.0; |
tylerjw | 5:94daced1e61a | 49 | } else { |
tylerjw | 5:94daced1e61a | 50 | v = floor(v); |
tylerjw | 5:94daced1e61a | 51 | } |
tylerjw | 5:94daced1e61a | 52 | return v; |
tylerjw | 5:94daced1e61a | 53 | } |
tylerjw | 5:94daced1e61a | 54 | |
tylerjw | 5:94daced1e61a | 55 | // GET FUNCTIONS ///////////////////////////////////////////////////////////////// |
tylerjw | 6:4ed12067a314 | 56 | |
tylerjw | 5:94daced1e61a | 57 | float GPS_Parser::get_msl_altitude() |
tylerjw | 5:94daced1e61a | 58 | { |
tylerjw | 5:94daced1e61a | 59 | if (!lock) |
tylerjw | 5:94daced1e61a | 60 | return 0.0; |
tylerjw | 5:94daced1e61a | 61 | else |
tylerjw | 5:94daced1e61a | 62 | return msl_altitude; |
tylerjw | 5:94daced1e61a | 63 | } |
tylerjw | 5:94daced1e61a | 64 | |
tylerjw | 7:01a8379370e4 | 65 | int GPS_Parser::get_satellites() |
tylerjw | 5:94daced1e61a | 66 | { |
tylerjw | 5:94daced1e61a | 67 | if (!lock) |
tylerjw | 5:94daced1e61a | 68 | return 0; |
tylerjw | 5:94daced1e61a | 69 | else |
tylerjw | 7:01a8379370e4 | 70 | return satellites; |
tylerjw | 5:94daced1e61a | 71 | } |
tylerjw | 5:94daced1e61a | 72 | |
tylerjw | 5:94daced1e61a | 73 | float GPS_Parser::get_nmea_longitude() |
tylerjw | 5:94daced1e61a | 74 | { |
tylerjw | 5:94daced1e61a | 75 | if (!lock) |
tylerjw | 5:94daced1e61a | 76 | return 0.0; |
tylerjw | 5:94daced1e61a | 77 | else |
tylerjw | 5:94daced1e61a | 78 | return nmea_longitude; |
tylerjw | 5:94daced1e61a | 79 | } |
tylerjw | 5:94daced1e61a | 80 | |
tylerjw | 5:94daced1e61a | 81 | float GPS_Parser::get_dec_longitude() |
tylerjw | 5:94daced1e61a | 82 | { |
tylerjw | 5:94daced1e61a | 83 | dec_longitude = nmea_to_dec(nmea_longitude, ew); |
tylerjw | 5:94daced1e61a | 84 | if (!lock) |
tylerjw | 5:94daced1e61a | 85 | return 0.0; |
tylerjw | 5:94daced1e61a | 86 | else |
tylerjw | 5:94daced1e61a | 87 | return dec_longitude; |
tylerjw | 5:94daced1e61a | 88 | } |
tylerjw | 5:94daced1e61a | 89 | |
tylerjw | 5:94daced1e61a | 90 | float GPS_Parser::get_nmea_latitude() |
tylerjw | 5:94daced1e61a | 91 | { |
tylerjw | 5:94daced1e61a | 92 | if (!lock) |
tylerjw | 5:94daced1e61a | 93 | return 0.0; |
tylerjw | 5:94daced1e61a | 94 | else |
tylerjw | 5:94daced1e61a | 95 | return nmea_latitude; |
tylerjw | 5:94daced1e61a | 96 | } |
tylerjw | 5:94daced1e61a | 97 | |
tylerjw | 5:94daced1e61a | 98 | float GPS_Parser::get_dec_latitude() |
tylerjw | 5:94daced1e61a | 99 | { |
tylerjw | 5:94daced1e61a | 100 | dec_latitude = nmea_to_dec(nmea_latitude, ns); |
tylerjw | 5:94daced1e61a | 101 | if (!lock) |
tylerjw | 5:94daced1e61a | 102 | return 0.0; |
tylerjw | 5:94daced1e61a | 103 | else |
tylerjw | 5:94daced1e61a | 104 | return dec_latitude; |
tylerjw | 5:94daced1e61a | 105 | } |
tylerjw | 5:94daced1e61a | 106 | |
tylerjw | 7:01a8379370e4 | 107 | float GPS_Parser::get_course_d() |
tylerjw | 5:94daced1e61a | 108 | { |
tylerjw | 5:94daced1e61a | 109 | if (!lock) |
tylerjw | 5:94daced1e61a | 110 | return 0.0; |
tylerjw | 5:94daced1e61a | 111 | else |
tylerjw | 7:01a8379370e4 | 112 | return course_d; |
tylerjw | 5:94daced1e61a | 113 | } |
tylerjw | 5:94daced1e61a | 114 | |
tylerjw | 5:94daced1e61a | 115 | float GPS_Parser::get_speed_k() |
tylerjw | 5:94daced1e61a | 116 | { |
tylerjw | 5:94daced1e61a | 117 | if (!lock) |
tylerjw | 5:94daced1e61a | 118 | return 0.0; |
tylerjw | 5:94daced1e61a | 119 | else |
tylerjw | 5:94daced1e61a | 120 | return speed_k; |
tylerjw | 5:94daced1e61a | 121 | } |
tylerjw | 5:94daced1e61a | 122 | |
tylerjw | 5:94daced1e61a | 123 | float GPS_Parser::get_altitude_ft() |
tylerjw | 5:94daced1e61a | 124 | { |
tylerjw | 5:94daced1e61a | 125 | if (!lock) |
tylerjw | 5:94daced1e61a | 126 | return 0.0; |
tylerjw | 5:94daced1e61a | 127 | else |
tylerjw | 5:94daced1e61a | 128 | return 3.280839895*msl_altitude; |
tylerjw | 5:94daced1e61a | 129 | } |
tylerjw | 5:94daced1e61a | 130 | |
tylerjw | 5:94daced1e61a | 131 | // NAVIGATION FUNCTIONS //////////////////////////////////////////////////////////// |
tylerjw | 5:94daced1e61a | 132 | float GPS_Parser::calc_course_to(float pointLat, float pontLong) |
tylerjw | 5:94daced1e61a | 133 | { |
tylerjw | 5:94daced1e61a | 134 | const double d2r = PI / 180.0; |
tylerjw | 5:94daced1e61a | 135 | const double r2d = 180.0 / PI; |
tylerjw | 5:94daced1e61a | 136 | double dlat = abs(pointLat - get_dec_latitude()) * d2r; |
tylerjw | 5:94daced1e61a | 137 | double dlong = abs(pontLong - get_dec_longitude()) * d2r; |
tylerjw | 5:94daced1e61a | 138 | double y = sin(dlong) * cos(pointLat * d2r); |
tylerjw | 5:94daced1e61a | 139 | double x = cos(get_dec_latitude()*d2r)*sin(pointLat*d2r) - sin(get_dec_latitude()*d2r)*cos(pointLat*d2r)*cos(dlong); |
tylerjw | 5:94daced1e61a | 140 | return 360.0-(atan2(y,x)*r2d); |
tylerjw | 5:94daced1e61a | 141 | } |
tylerjw | 5:94daced1e61a | 142 | |
tylerjw | 5:94daced1e61a | 143 | /* |
tylerjw | 5:94daced1e61a | 144 | var y = Math.sin(dLon) * Math.cos(lat2); |
tylerjw | 5:94daced1e61a | 145 | var x = Math.cos(lat1)*Math.sin(lat2) - |
tylerjw | 5:94daced1e61a | 146 | Math.sin(lat1)*Math.cos(lat2)*Math.cos(dLon); |
tylerjw | 5:94daced1e61a | 147 | var brng = Math.atan2(y, x).toDeg(); |
tylerjw | 5:94daced1e61a | 148 | */ |
tylerjw | 5:94daced1e61a | 149 | |
tylerjw | 5:94daced1e61a | 150 | /* |
tylerjw | 5:94daced1e61a | 151 | The Haversine formula according to Dr. Math. |
tylerjw | 5:94daced1e61a | 152 | http://mathforum.org/library/drmath/view/51879.html |
tylerjw | 5:94daced1e61a | 153 | |
tylerjw | 5:94daced1e61a | 154 | dlon = lon2 - lon1 |
tylerjw | 5:94daced1e61a | 155 | dlat = lat2 - lat1 |
tylerjw | 5:94daced1e61a | 156 | a = (sin(dlat/2))^2 + cos(lat1) * cos(lat2) * (sin(dlon/2))^2 |
tylerjw | 5:94daced1e61a | 157 | c = 2 * atan2(sqrt(a), sqrt(1-a)) |
tylerjw | 5:94daced1e61a | 158 | d = R * c |
tylerjw | 5:94daced1e61a | 159 | |
tylerjw | 5:94daced1e61a | 160 | Where |
tylerjw | 5:94daced1e61a | 161 | * dlon is the change in longitude |
tylerjw | 5:94daced1e61a | 162 | * dlat is the change in latitude |
tylerjw | 5:94daced1e61a | 163 | * c is the great circle distance in Radians. |
tylerjw | 5:94daced1e61a | 164 | * R is the radius of a spherical Earth. |
tylerjw | 5:94daced1e61a | 165 | * The locations of the two points in |
tylerjw | 5:94daced1e61a | 166 | spherical coordinates (longitude and |
tylerjw | 5:94daced1e61a | 167 | latitude) are lon1,lat1 and lon2, lat2. |
tylerjw | 5:94daced1e61a | 168 | */ |
tylerjw | 5:94daced1e61a | 169 | double GPS_Parser::calc_dist_to_mi(float pointLat, float pontLong) |
tylerjw | 5:94daced1e61a | 170 | { |
tylerjw | 5:94daced1e61a | 171 | const double d2r = PI / 180.0; |
tylerjw | 5:94daced1e61a | 172 | double dlat = pointLat - get_dec_latitude(); |
tylerjw | 5:94daced1e61a | 173 | double dlong = pontLong - get_dec_longitude(); |
tylerjw | 5:94daced1e61a | 174 | 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 | 175 | double c = 2.0 * asin(sqrt(abs(a))); |
tylerjw | 5:94daced1e61a | 176 | double d = 63.765 * c; |
tylerjw | 5:94daced1e61a | 177 | |
tylerjw | 5:94daced1e61a | 178 | return d; |
tylerjw | 5:94daced1e61a | 179 | } |
tylerjw | 5:94daced1e61a | 180 | |
tylerjw | 5:94daced1e61a | 181 | double GPS_Parser::calc_dist_to_ft(float pointLat, float pontLong) |
tylerjw | 5:94daced1e61a | 182 | { |
tylerjw | 5:94daced1e61a | 183 | return calc_dist_to_mi(pointLat, pontLong)*5280.0; |
tylerjw | 5:94daced1e61a | 184 | } |
tylerjw | 5:94daced1e61a | 185 | |
tylerjw | 5:94daced1e61a | 186 | double GPS_Parser::calc_dist_to_km(float pointLat, float pontLong) |
tylerjw | 5:94daced1e61a | 187 | { |
tylerjw | 5:94daced1e61a | 188 | return calc_dist_to_mi(pointLat, pontLong)*1.609344; |
tylerjw | 5:94daced1e61a | 189 | } |
tylerjw | 5:94daced1e61a | 190 | |
tylerjw | 5:94daced1e61a | 191 | double GPS_Parser::calc_dist_to_m(float pointLat, float pontLong) |
tylerjw | 5:94daced1e61a | 192 | { |
tylerjw | 5:94daced1e61a | 193 | return calc_dist_to_mi(pointLat, pontLong)*1609.344; |
tylerjw | 5:94daced1e61a | 194 | } |
tylerjw | 5:94daced1e61a | 195 | |
tylerjw | 7:01a8379370e4 | 196 | char *GPS_Parser::my_token(char *source,char token) |
tylerjw | 7:01a8379370e4 | 197 | { |
tylerjw | 7:01a8379370e4 | 198 | char *start; |
tylerjw | 7:01a8379370e4 | 199 | /* The source string is real only for the first call. Subsequent calls |
tylerjw | 7:01a8379370e4 | 200 | are made with the source string pointer as NULL |
tylerjw | 7:01a8379370e4 | 201 | */ |
tylerjw | 7:01a8379370e4 | 202 | if(source != NULL) { |
tylerjw | 7:01a8379370e4 | 203 | /* If the string is empty return NULL */ |
tylerjw | 7:01a8379370e4 | 204 | if(strlen(source) == 0) |
tylerjw | 7:01a8379370e4 | 205 | return NULL; |
tylerjw | 7:01a8379370e4 | 206 | strcpy(stat_string,source); |
tylerjw | 7:01a8379370e4 | 207 | /* Current is our 'current' position within the string */ |
tylerjw | 7:01a8379370e4 | 208 | current = stat_string; |
tylerjw | 7:01a8379370e4 | 209 | } |
tylerjw | 7:01a8379370e4 | 210 | start = current; |
tylerjw | 7:01a8379370e4 | 211 | |
tylerjw | 7:01a8379370e4 | 212 | while (true) { |
tylerjw | 7:01a8379370e4 | 213 | /* If we're at the end of the string, return NULL */ |
tylerjw | 7:01a8379370e4 | 214 | if((*current == '\0') && (current == start)) |
tylerjw | 7:01a8379370e4 | 215 | return NULL; |
tylerjw | 7:01a8379370e4 | 216 | /* If we're at the end now, but weren't when we started, we need |
tylerjw | 7:01a8379370e4 | 217 | to return the pointer for the last field before the end of string |
tylerjw | 7:01a8379370e4 | 218 | */ |
tylerjw | 7:01a8379370e4 | 219 | if(*current == '\0') |
tylerjw | 7:01a8379370e4 | 220 | return start; |
tylerjw | 7:01a8379370e4 | 221 | /* If we've located our specified token (comma) in the string |
tylerjw | 7:01a8379370e4 | 222 | load its location in the copy with an end of string marker |
tylerjw | 7:01a8379370e4 | 223 | so that it can be handled correctly by the calling program. |
tylerjw | 7:01a8379370e4 | 224 | */ |
tylerjw | 7:01a8379370e4 | 225 | if(*current == token) { |
tylerjw | 7:01a8379370e4 | 226 | *current = '\0'; |
tylerjw | 7:01a8379370e4 | 227 | current++; |
tylerjw | 7:01a8379370e4 | 228 | return start; |
tylerjw | 7:01a8379370e4 | 229 | } else { |
tylerjw | 7:01a8379370e4 | 230 | current++; |
tylerjw | 7:01a8379370e4 | 231 | } |
tylerjw | 7:01a8379370e4 | 232 | } |
tylerjw | 7:01a8379370e4 | 233 | } |
tylerjw | 7:01a8379370e4 | 234 | |
tylerjw | 7:01a8379370e4 | 235 | int GPS_Parser::parse(char *string) |
tylerjw | 7:01a8379370e4 | 236 | { |
tylerjw | 7:01a8379370e4 | 237 | int field_count; |
tylerjw | 7:01a8379370e4 | 238 | field_count = 0; |
tylerjw | 7:01a8379370e4 | 239 | /* NMEA 0183 fields are delimited by commas. The my_token function returns |
tylerjw | 7:01a8379370e4 | 240 | pointers to the fields. |
tylerjw | 7:01a8379370e4 | 241 | */ |
tylerjw | 7:01a8379370e4 | 242 | /* Get the first field pointer */ |
tylerjw | 7:01a8379370e4 | 243 | field[0] = my_token(string,','); |
tylerjw | 7:01a8379370e4 | 244 | field_count++; |
tylerjw | 7:01a8379370e4 | 245 | |
tylerjw | 7:01a8379370e4 | 246 | while (true) { |
tylerjw | 7:01a8379370e4 | 247 | /* Contiue retrieving fields until there are no more (NULL) */ |
tylerjw | 7:01a8379370e4 | 248 | field[field_count] = my_token(NULL,','); |
tylerjw | 7:01a8379370e4 | 249 | if(field[field_count] == NULL) |
tylerjw | 7:01a8379370e4 | 250 | break; |
tylerjw | 7:01a8379370e4 | 251 | field_count++; |
tylerjw | 7:01a8379370e4 | 252 | } |
tylerjw | 7:01a8379370e4 | 253 | /* If we got at least ONE field */ |
tylerjw | 7:01a8379370e4 | 254 | if(field_count) { |
tylerjw | 7:01a8379370e4 | 255 | /* Check the first field for the valid NMEA 0183 headers */ |
tylerjw | 7:01a8379370e4 | 256 | if(strcmp(field[0],"$GPGGA") == 0) { |
tylerjw | 7:01a8379370e4 | 257 | /* Retrieve the values from the remaining fields */ |
tylerjw | 7:01a8379370e4 | 258 | utc_time = atof(field[1]); |
tylerjw | 7:01a8379370e4 | 259 | nmea_latitude = atof(field[2]); |
tylerjw | 7:01a8379370e4 | 260 | ns = *(field[3]); |
tylerjw | 7:01a8379370e4 | 261 | nmea_longitude = atof(field[4]); |
tylerjw | 7:01a8379370e4 | 262 | ew = *(field[5]); |
tylerjw | 7:01a8379370e4 | 263 | lock = atoi(field[6]); |
tylerjw | 7:01a8379370e4 | 264 | satellites = atoi(field[7]); |
tylerjw | 7:01a8379370e4 | 265 | hdop = atof(field[8]); |
tylerjw | 7:01a8379370e4 | 266 | msl_altitude = atof(field[9]); |
tylerjw | 7:01a8379370e4 | 267 | msl_units = *(field[10]); |
tylerjw | 7:01a8379370e4 | 268 | } |
tylerjw | 7:01a8379370e4 | 269 | if(strcmp(field[0],"$GPRMC") == 0) { |
tylerjw | 7:01a8379370e4 | 270 | /* Retrieve the data from the remaining fields */ |
tylerjw | 7:01a8379370e4 | 271 | utc_time = atof(field[1]); |
tylerjw | 7:01a8379370e4 | 272 | nmea_latitude = atof(field[3]); |
tylerjw | 7:01a8379370e4 | 273 | ns = *(field[4]); |
tylerjw | 7:01a8379370e4 | 274 | nmea_longitude = atof(field[5]); |
tylerjw | 7:01a8379370e4 | 275 | ew = *(field[6]); |
tylerjw | 7:01a8379370e4 | 276 | speed_k = atof(field[7]); |
tylerjw | 7:01a8379370e4 | 277 | course_d = atof(field[8]); |
tylerjw | 7:01a8379370e4 | 278 | date = atol(field[9]); |
tylerjw | 7:01a8379370e4 | 279 | } |
tylerjw | 7:01a8379370e4 | 280 | } |
tylerjw | 7:01a8379370e4 | 281 | return field_count; |
tylerjw | 7:01a8379370e4 | 282 | } |