christian b / GPS

Mbed library to handle GPS data reception and parsing

Dependents:   GPS_U-blox_NEO-6M_Code

Features

  • All positionning parameters are contained into a global data structure.
  • Automatic nema string parsing and data structure update.
    • GSA,GGA,VTG and RMC
  • Convert latitude and longitude to decimal value.
  • Converts latittude,longitude and altitude to ECEF coordinates.

Planed developement

  • Test library for RTOS use.
  • Complete the nema parsing decoders (couple of parameters are not parsed yet and not present in the data structure).
  • Add conversion tool to get ENU coordinates.

utils/GPSUtils.hpp@1:fade122a76a8, 2015-04-06 (annotated)

Committer:
chris215
Date:
Mon Apr 06 17:41:43 2015 +0000
Revision:
1:fade122a76a8
Parent:
0:0c1aa5906cef
Child:
2:72ac4d7044a7
various updates;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
chris215 0:0c1aa5906cef 1 #ifndef _GPSUTILS_H_
chris215 0:0c1aa5906cef 2 #define _GPSUTILS_H_
chris215 0:0c1aa5906cef 3
chris215 0:0c1aa5906cef 4 #include "mbedGPSDefs.h"
chris215 0:0c1aa5906cef 5 #include "GPGGAdecoder.hpp"
chris215 0:0c1aa5906cef 6 #include "GPVTGdecoder.hpp"
chris215 0:0c1aa5906cef 7 #include "GPGSAdecoder.hpp"
chris215 0:0c1aa5906cef 8 #include "GPRMCdecoder.hpp"
chris215 0:0c1aa5906cef 9 #include "WGS84.h"
chris215 0:0c1aa5906cef 10
chris215 0:0c1aa5906cef 11 #define PI 3.141592653589793238462643383279502884
chris215 0:0c1aa5906cef 12 #define RADIANS_TO_DEGREES(radians) ((radians) * (180.0 / PI))
chris215 0:0c1aa5906cef 13 #define DEGREES_TO_RADIANS ( PI / 180.0)
chris215 0:0c1aa5906cef 14 #define WGS84_A 6378137.000
chris215 0:0c1aa5906cef 15 //298.257223563
chris215 0:0c1aa5906cef 16 #define WGS84_E 0.081819190842621
chris215 0:0c1aa5906cef 17
chris215 0:0c1aa5906cef 18
chris215 0:0c1aa5906cef 19 /*
chris215 0:0c1aa5906cef 20 Source of information about nema sentences :
chris215 0:0c1aa5906cef 21 http://www.gpsinformation.org/dale/nmea.htm
chris215 0:0c1aa5906cef 22 */
chris215 0:0c1aa5906cef 23 void DecodeMessage(message& msg,GPSInfo& data)
chris215 0:0c1aa5906cef 24 {
chris215 0:0c1aa5906cef 25
chris215 0:0c1aa5906cef 26 if(strstr(msg.data,GPS_CMD_GPGGA)){
chris215 0:0c1aa5906cef 27 DecodeGPGGA(msg.data,data);
chris215 0:0c1aa5906cef 28 }
chris215 0:0c1aa5906cef 29
chris215 0:0c1aa5906cef 30 if(strstr(msg.data,GPS_CMD_GPVTG)){
chris215 0:0c1aa5906cef 31 DecodeGPVTG(msg.data,data);
chris215 0:0c1aa5906cef 32 }
chris215 0:0c1aa5906cef 33
chris215 0:0c1aa5906cef 34 if(strstr(msg.data,GPS_CMD_GPGSA)){
chris215 0:0c1aa5906cef 35 DecodeGPGSA(msg.data,data);
chris215 0:0c1aa5906cef 36 }
chris215 0:0c1aa5906cef 37 if(strstr(msg.data,GPS_CMD_GPRMC)){
chris215 0:0c1aa5906cef 38 DecodeGPRMC(msg.data,data);
chris215 0:0c1aa5906cef 39 }
chris215 0:0c1aa5906cef 40 }
chris215 0:0c1aa5906cef 41
chris215 0:0c1aa5906cef 42 ECEFPoint GeoDesicToECEF(geodPoint p)
chris215 0:0c1aa5906cef 43 {
chris215 0:0c1aa5906cef 44 ECEFPoint newECEFpoint;
chris215 0:0c1aa5906cef 45 double lat = 0.0;
chris215 0:0c1aa5906cef 46 double lon = 0.0;
chris215 0:0c1aa5906cef 47 lat = p.latitude;
chris215 0:0c1aa5906cef 48 lon = p.longitude;
chris215 0:0c1aa5906cef 49
chris215 0:0c1aa5906cef 50 double clat = cos(lat * DEGREES_TO_RADIANS);
chris215 0:0c1aa5906cef 51 double slat = sin(lat * DEGREES_TO_RADIANS);
chris215 0:0c1aa5906cef 52 double clon = cos(lon * DEGREES_TO_RADIANS);
chris215 0:0c1aa5906cef 53 double slon = sin(lon * DEGREES_TO_RADIANS);
chris215 0:0c1aa5906cef 54
chris215 0:0c1aa5906cef 55 double N = WGS84_A / sqrt(1.0 - WGS84_E * WGS84_E * slat * slat);
chris215 0:0c1aa5906cef 56
chris215 0:0c1aa5906cef 57 newECEFpoint.x = (N + p.altitude) * clat * clon;
chris215 0:0c1aa5906cef 58 newECEFpoint.y = (N + p.altitude) * clat * slon;
chris215 0:0c1aa5906cef 59 newECEFpoint.z = (N * (1.0 - WGS84_E * WGS84_E) + p.altitude) * slat;
chris215 0:0c1aa5906cef 60
chris215 0:0c1aa5906cef 61 return newECEFpoint;
chris215 0:0c1aa5906cef 62 }
chris215 0:0c1aa5906cef 63
chris215 0:0c1aa5906cef 64 ECEFDistance DistanceBetweenTwoECEFPoints(ECEFPoint p1, ECEFPoint p2)
chris215 0:0c1aa5906cef 65 {
chris215 0:0c1aa5906cef 66 ECEFDistance newDistance;
chris215 0:0c1aa5906cef 67 newDistance.dx = p1.x-p2.x;
chris215 0:0c1aa5906cef 68 newDistance.dy = p1.y-p2.y;
chris215 0:0c1aa5906cef 69 newDistance.dz = p1.z-p2.z;
chris215 0:0c1aa5906cef 70 newDistance.d = sqrt((newDistance.dx*newDistance.dx) + (newDistance.dy*newDistance.dy) + (newDistance.dz*newDistance.dz));
chris215 0:0c1aa5906cef 71 return newDistance;
chris215 0:0c1aa5906cef 72 }
chris215 0:0c1aa5906cef 73
chris215 0:0c1aa5906cef 74 float nmea_to_dec(double nema_coor, char nsew) {
chris215 0:0c1aa5906cef 75 int degree = (int)(nema_coor/100);
chris215 0:0c1aa5906cef 76 double minutes = nema_coor - degree*100;
chris215 0:0c1aa5906cef 77 double dec_deg = minutes / 60;
chris215 0:0c1aa5906cef 78 double decimal = degree + dec_deg;
chris215 0:0c1aa5906cef 79 if (nsew == 'S' || nsew == 'W') { // return negative
chris215 0:0c1aa5906cef 80 decimal *= -1;
chris215 0:0c1aa5906cef 81 }
chris215 0:0c1aa5906cef 82 return decimal;
chris215 0:0c1aa5906cef 83 }
chris215 1:fade122a76a8 84
chris215 1:fade122a76a8 85 // Coverts ECEF to ENU coordinates centered at given lat, lon
chris215 1:fade122a76a8 86 void ecefToEnu(double lat, double lon, double x, double y, double z, double xr, double yr, double zr, double *e, double *n, double *u)
chris215 1:fade122a76a8 87 {
chris215 1:fade122a76a8 88 double clat = cos(lat * DEGREES_TO_RADIANS);
chris215 1:fade122a76a8 89 double slat = sin(lat * DEGREES_TO_RADIANS);
chris215 1:fade122a76a8 90 double clon = cos(lon * DEGREES_TO_RADIANS);
chris215 1:fade122a76a8 91 double slon = sin(lon * DEGREES_TO_RADIANS);
chris215 1:fade122a76a8 92 double dx = x - xr;
chris215 1:fade122a76a8 93 double dy = y - yr;
chris215 1:fade122a76a8 94 double dz = z - zr;
chris215 1:fade122a76a8 95
chris215 1:fade122a76a8 96 *e = -slon*dx + clon*dy;
chris215 1:fade122a76a8 97 *n = -slat*clon*dx - slat*slon*dy + clat*dz;
chris215 1:fade122a76a8 98 *u = clat*clon*dx + clat*slon*dy + slat*dz;
chris215 1:fade122a76a8 99 }
chris215 0:0c1aa5906cef 100 #endif