GroveGPS.h

00001 #ifndef _GROVE_GPS_H_
00002 #define _GROVE_GPS_H_
00003 
00004 #include "mbed.h"
00005 #include <stdlib.h>
00006 #include <string>
00007 
00008 
00009 class GroveGPS {
00010 
00011 public:
00012 
00013     GroveGPS() : _last_line("") {
00014 
00015     }
00016 
00017     std::string _last_line;
00018     
00019     struct GGA {
00020         double  utc_time;       // Format: hhmmss.sss
00021         double  latitude;       // Format: ddmm.mmmm
00022         char    ns_indicator;   // Format: N=north or S=south
00023         double  longitude;      // Format: dddmm.mmmm
00024         char    ew_indicator;   // Format: E=east or W=west
00025         int position_fix;   // Options: [0=not available, 1=GPS SPS mode, 2=Differential GPS, 6=dead reckoning]
00026         int sats_used;      // Range: 0-12
00027         double  hdop;           // Horizontal Dilution of Precision
00028         double  msl_altitude;
00029         char    msl_altitude_units;
00030         double  geoid_separation;
00031         char    geoid_separation_units;
00032         long    age_of_diff;
00033         long    diff_ref_station_id;
00034         int     new_flag;
00035         std::string  checksum;
00036     } gps_gga;
00037     
00038     struct ZDA {
00039         double  utc_time;       // Format: hhmmss.sss
00040         int day;
00041         int month;
00042         int year;
00043         int new_flag;
00044         std::string  checksum;
00045     } gps_zda;
00046 
00047     struct VTG {
00048         double  course1; 
00049         int truec;
00050         double  course2; 
00051         int magnetic;
00052         double  speed1; 
00053         int knots;
00054         double  speed2; 
00055         int kmh;
00056         int new_flag;
00057         std::string  checksum;
00058     } gps_vtg;
00059 
00060     void getTimestamp(char* buffer) {
00061         if (gps_gga.position_fix==0)
00062             sprintf(buffer, "N/A");
00063         else
00064             sprintf(buffer, "%f", gps_gga.utc_time);
00065     }
00066     
00067     void getAltitude(char* buffer) {
00068         if (gps_gga.position_fix==0)
00069             sprintf(buffer, "N/A");
00070         else
00071             sprintf(buffer, "%f", gps_gga.msl_altitude);
00072     }
00073    
00074     void getCourse(char* buffer) {
00075         if (gps_gga.position_fix==0)
00076             sprintf(buffer, "N/A");
00077         else
00078             sprintf(buffer, "%f", gps_vtg.course1);
00079     }
00080     
00081     void getSpeed(char* buffer) {
00082         if (gps_gga.position_fix==0)
00083             sprintf(buffer, "N/A");
00084         else
00085             sprintf(buffer, "%f", gps_vtg.speed1);
00086     }
00087 
00088     
00089     void getUncertanty(char* buffer) {
00090         if (gps_gga.position_fix==0)
00091             sprintf(buffer, "N/A");
00092         else
00093             sprintf(buffer, "%f", gps_gga.hdop);
00094     }
00095         
00096     void getLatitude(char* buffer) {
00097         double coordinate = convertGPSToDecimal(gps_gga.latitude);
00098         if (gps_gga.position_fix==0) {
00099             sprintf(buffer, "N/A");
00100         } else {    
00101         if(gps_gga.ns_indicator == 'S') coordinate *= -1.000;
00102         sprintf(buffer, "%f", coordinate);
00103         }
00104     }
00105 
00106     void getLongitude(char* buffer) {
00107         double coordinate = convertGPSToDecimal(gps_gga.longitude);
00108         if (gps_gga.position_fix==0)
00109             sprintf(buffer, "N/A");
00110         else {
00111         if(gps_gga.ew_indicator == 'W') coordinate *= -1.0000;
00112         sprintf(buffer, "%f", coordinate);
00113         }
00114     }
00115 
00116 
00117     double convertGPSToDecimal(double coordinate) {
00118         int degrees = coordinate/100.0;
00119         int minutes = ((int)coordinate) % 100;
00120         double seconds = coordinate - ((int)coordinate);
00121         return degrees + (minutes+seconds)/60;
00122 
00123     }
00124 
00125 void parseVTG() {
00126         char* pEnd;
00127         for (int i=0; i<5; i++) {
00128             std::string current_item = _last_line.substr(0,_last_line.find(","));
00129             _last_line = _last_line.substr(_last_line.find(",")+1);
00130             if (i==0) {         // NMEA Tag
00131             } else if (i==1) {  // UTC time
00132                 gps_vtg.course1 = strtod(current_item.c_str(), &pEnd);
00133             } else if (i==3) {
00134                 gps_vtg.course2 = strtod(current_item.c_str(), &pEnd);
00135             } else if (i==5) {
00136                 gps_vtg.speed1 = strtod(current_item.c_str(), &pEnd);
00137             } else if (i==7) {
00138                 gps_vtg.speed2 = strtod(current_item.c_str(), &pEnd);
00139             }
00140             if(gps_vtg.course2 > gps_vtg.course1) gps_vtg.course1 = gps_vtg.course2;
00141             if(gps_vtg.speed2 > gps_vtg.speed1) gps_vtg.speed1 = gps_vtg.speed2;
00142         }
00143     gps_vtg.new_flag = 1;   
00144     }
00145         
00146 void parseZDA() {
00147         char* pEnd;
00148         for (int i=0; i<5; i++) {
00149             std::string current_item = _last_line.substr(0,_last_line.find(","));
00150             _last_line = _last_line.substr(_last_line.find(",")+1);
00151             if (i==0) {         // NMEA Tag
00152             } else if (i==1) {  // UTC time
00153                 gps_zda.utc_time = strtod(current_item.c_str(), &pEnd);
00154             } else if (i==2) {
00155                 gps_zda.day = strtod(current_item.c_str(), &pEnd);
00156             } else if (i==3) {
00157                 gps_zda.month = strtod(current_item.c_str(), &pEnd);
00158             } else if (i==4) {
00159                 gps_zda.year = strtod(current_item.c_str(), &pEnd);
00160             }
00161         }
00162     gps_zda.new_flag = 1;   
00163     }
00164 
00165     void parseGGA() {
00166         char* pEnd;
00167         for (int i=0; i<14; i++) {
00168             std::string current_item = _last_line.substr(0,_last_line.find(","));
00169             _last_line = _last_line.substr(_last_line.find(",")+1);
00170             if (i==0) {         // NMEA Tag
00171             } else if (i==1) {  // UTC time
00172                 gps_gga.utc_time = strtod(current_item.c_str(), &pEnd);
00173             } else if (i==2) {  // Latitude
00174                 gps_gga.latitude = strtod(current_item.c_str(), &pEnd);
00175             } else if (i==3) {  // Latitude North/South indicator
00176                 gps_gga.ns_indicator = current_item[0];
00177             } else if (i==4) {  // Longitude
00178                 gps_gga.longitude = strtod(current_item.c_str(), &pEnd);
00179             } else if (i==5) {  // Longitude indicator
00180                 gps_gga.ew_indicator = current_item[0];
00181             } else if (i==6) {
00182                 gps_gga.position_fix = strtod(current_item.c_str(), &pEnd);
00183             }else if (i==7) {
00184                 gps_gga.sats_used = strtod(current_item.c_str(), &pEnd);
00185             } else if (i==8) { // Uncertanty
00186                 gps_gga.hdop = strtod(current_item.c_str(), &pEnd);
00187             } else if (i==9) { //  Altitude mean sea level
00188                 gps_gga.msl_altitude = strtod(current_item.c_str(), &pEnd);
00189             } else if (i==11) {
00190                 gps_gga.geoid_separation = strtod(current_item.c_str(), &pEnd);
00191                 gps_gga.msl_altitude += gps_gga.geoid_separation;
00192             }
00193         }
00194     gps_gga.new_flag = 1;
00195     }
00196     
00197 };
00198 
00199 #endif