2021 mbed Grove GPS
GroveGPS.h@0:56d6407653a7, 2018-01-30 (annotated)
- Committer:
- michaelray
- Date:
- Tue Jan 30 13:04:53 2018 -0600
- Revision:
- 0:56d6407653a7
- Child:
- 1:0607ba3aa02d
Initial Commit
Who changed what in which revision?
User | Revision | Line number | New 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 |