Jim Carver / GroveGPS

Improved, thread compatible. Adds new features

Dependents:   GroveGPS-Example

Fork of GroveGPS by Michael Ray

GroveGPS.h@0:56d6407653a7, 2018-01-30 (annotated)

Committer:
michaelray
Date:
Tue Jan 30 13:04:53 2018 -0600
Revision:
0:56d6407653a7
Child:
1:403eb5e9e994
Initial Commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
michaelray 0:56d6407653a7 1 #ifndef _GROVE_GPS_H_
michaelray 0:56d6407653a7 2 #define _GROVE_GPS_H_
michaelray 0:56d6407653a7 3
michaelray 0:56d6407653a7 4 #include "mbed.h"
michaelray 0:56d6407653a7 5 #include <stdlib.h>
michaelray 0:56d6407653a7 6 #include <string>
michaelray 0:56d6407653a7 7
michaelray 0:56d6407653a7 8 class GroveGPS {
michaelray 0:56d6407653a7 9
michaelray 0:56d6407653a7 10 public:
michaelray 0:56d6407653a7 11
michaelray 0:56d6407653a7 12 GroveGPS() : _last_line("") {}
michaelray 0:56d6407653a7 13
michaelray 0:56d6407653a7 14 void readCharacter(char newCharacter) {
michaelray 0:56d6407653a7 15 if (newCharacter == '\n') {
michaelray 0:56d6407653a7 16 parseLine();
michaelray 0:56d6407653a7 17 _last_line = "";
michaelray 0:56d6407653a7 18 } else {
michaelray 0:56d6407653a7 19 _last_line += newCharacter;
michaelray 0:56d6407653a7 20 }
michaelray 0:56d6407653a7 21 }
michaelray 0:56d6407653a7 22
michaelray 0:56d6407653a7 23 struct GGA {
michaelray 0:56d6407653a7 24 double utc_time; // Format: hhmmss.sss
michaelray 0:56d6407653a7 25 double latitude; // Format: ddmm.mmmm
michaelray 0:56d6407653a7 26 char ns_indicator; // Format: N=north or S=south
michaelray 0:56d6407653a7 27 double longitude; // Format: dddmm.mmmm
michaelray 0:56d6407653a7 28 char ew_indicator; // Format: E=east or W=west
michaelray 0:56d6407653a7 29 int position_fix; // Options: [0=not available, 1=GPS SPS mode, 2=Differential GPS, 6=dead reckoning]
michaelray 0:56d6407653a7 30 int sats_used; // Range: 0-12
michaelray 0:56d6407653a7 31 double hdop; // Horizontal Dilution of Precision
michaelray 0:56d6407653a7 32 double msl_altitude;
michaelray 0:56d6407653a7 33 char msl_altitude_units;
michaelray 0:56d6407653a7 34 double geoid_separation;
michaelray 0:56d6407653a7 35 char geoid_separation_units;
michaelray 0:56d6407653a7 36 long age_of_diff;
michaelray 0:56d6407653a7 37 long diff_ref_station_id;
michaelray 0:56d6407653a7 38 std::string checksum;
michaelray 0:56d6407653a7 39 } gps_gga;
michaelray 0:56d6407653a7 40
michaelray 0:56d6407653a7 41 void getTimestamp(char* buffer) {
michaelray 0:56d6407653a7 42 sprintf(buffer, "%f", gps_gga.utc_time);
michaelray 0:56d6407653a7 43 }
michaelray 0:56d6407653a7 44
michaelray 0:56d6407653a7 45 void getLatitude(char* buffer) {
michaelray 0:56d6407653a7 46 double coordinate = convertGPSToDecimal(gps_gga.latitude);
michaelray 0:56d6407653a7 47 if (gps_gga.position_fix==0)
michaelray 0:56d6407653a7 48 sprintf(buffer, "N/A");
michaelray 0:56d6407653a7 49 else
michaelray 0:56d6407653a7 50 sprintf(buffer, "%c%f", (gps_gga.ns_indicator == 'N') ? '0' : '-', coordinate);
michaelray 0:56d6407653a7 51 }
michaelray 0:56d6407653a7 52
michaelray 0:56d6407653a7 53 void getLongitude(char* buffer) {
michaelray 0:56d6407653a7 54 double coordinate = convertGPSToDecimal(gps_gga.longitude);
michaelray 0:56d6407653a7 55 if (gps_gga.position_fix==0)
michaelray 0:56d6407653a7 56 sprintf(buffer, "N/A");
michaelray 0:56d6407653a7 57 else
michaelray 0:56d6407653a7 58 sprintf(buffer, "%c%f", (gps_gga.ew_indicator == 'E') ? '0' : '-', coordinate);
michaelray 0:56d6407653a7 59 }
michaelray 0:56d6407653a7 60
michaelray 0:56d6407653a7 61 private:
michaelray 0:56d6407653a7 62 std::string _last_line;
michaelray 0:56d6407653a7 63
michaelray 0:56d6407653a7 64 double convertGPSToDecimal(double coordinate) {
michaelray 0:56d6407653a7 65 int degrees = coordinate/100.0;
michaelray 0:56d6407653a7 66 int minutes = ((int)coordinate) % 100;
michaelray 0:56d6407653a7 67 double seconds = coordinate - ((int)coordinate);
michaelray 0:56d6407653a7 68 return degrees + (minutes+seconds)/60;
michaelray 0:56d6407653a7 69
michaelray 0:56d6407653a7 70 }
michaelray 0:56d6407653a7 71
michaelray 0:56d6407653a7 72 void parseLine() {
michaelray 0:56d6407653a7 73 if (_last_line.find("GPGGA") != std::string::npos) {
michaelray 0:56d6407653a7 74 parseGGA();
michaelray 0:56d6407653a7 75 }
michaelray 0:56d6407653a7 76 }
michaelray 0:56d6407653a7 77
michaelray 0:56d6407653a7 78 void parseGGA() {
michaelray 0:56d6407653a7 79 char* pEnd;
michaelray 0:56d6407653a7 80 for (int i=0; i<14; i++) {
michaelray 0:56d6407653a7 81 std::string current_item = _last_line.substr(0,_last_line.find(","));
michaelray 0:56d6407653a7 82 _last_line = _last_line.substr(_last_line.find(",")+1);
michaelray 0:56d6407653a7 83 if (i==0) { // NMEA Tag
michaelray 0:56d6407653a7 84 } else if (i==1) { // UTC time
michaelray 0:56d6407653a7 85 gps_gga.utc_time = strtod(current_item.c_str(), &pEnd);
michaelray 0:56d6407653a7 86 } else if (i==2) { // Latitude
michaelray 0:56d6407653a7 87 gps_gga.latitude = strtod(current_item.c_str(), &pEnd);
michaelray 0:56d6407653a7 88 } else if (i==3) { // Latitude North/South indicator
michaelray 0:56d6407653a7 89 gps_gga.ns_indicator = current_item[0];
michaelray 0:56d6407653a7 90 } else if (i==4) { // Longitude
michaelray 0:56d6407653a7 91 gps_gga.longitude = strtod(current_item.c_str(), &pEnd);
michaelray 0:56d6407653a7 92 } else if (i==5) { // Longitude indicator
michaelray 0:56d6407653a7 93 gps_gga.ew_indicator = current_item[0];
michaelray 0:56d6407653a7 94 } else if (i==6) {
michaelray 0:56d6407653a7 95 gps_gga.position_fix = strtod(current_item.c_str(), &pEnd);
michaelray 0:56d6407653a7 96 }
michaelray 0:56d6407653a7 97 }
michaelray 0:56d6407653a7 98 }
michaelray 0:56d6407653a7 99 };
michaelray 0:56d6407653a7 100
michaelray 0:56d6407653a7 101 #endif