File content as of revision 0:02573593bcdc:

#include "mbed.h"
#include "MBed_Adafruit_GPS.h"

int main()
{

    int flag = 0;

    Serial* gps_Serial = new Serial(p28,p27);
    Adafruit_GPS myGPS(gps_Serial);
    myGPS.begin(9600);

    const double target_x = 37.524988, target_y = 139.938585;
    double robot_x = 0.0, robot_y = 0.0;
    double sub_x = 0.0, sub_y = 0.0;
    double distance = 0.0;
    Timer GPS_Timer;
    GPS_Timer.start();
    const int GPS_Time = 1000;

    myGPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCONLY);
    myGPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ);
    myGPS.sendCommand(PGCMD_ANTENNA);

    while(true) {

        myGPS.read();
        if ( myGPS.newNMEAreceived() ) {
            if ( !myGPS.parse(myGPS.lastNMEA()) ) {
                continue;
            }
        }

        if (GPS_Timer.read_ms() >= GPS_Time) {
            GPS_Timer.reset();
            if(myGPS.fix) {
                robot_x = (double)myGPS.latitudeH + (double)(myGPS.latitudeL / 10000.0 / 60.0);
                robot_y = (double)myGPS.longitudeH +(double)(myGPS.longitudeL / 10000.0 / 60.0);
            }

            sub_x = (abs(target_x) - abs(robot_x)) * 111135.0;
            sub_y = (abs(target_y) - abs(robot_y)) * 91191.0;
            distance = sqrt(sub_x*sub_x - sub_y*sub_y);
            printf("latitude:%f, longitude:%f, distance:%f\n", robot_x, robot_y, distance);

        }
    }
    return 0;
}