GPS.cpp: 
/* mbed EM-406 GPS Module Library
 * Copyright (c) 2008-2010, sford
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
 
#include "GPS.h"



GPS::GPS(PinName tx, PinName rx) : _gps(tx, rx) {
    _gps.baud(4800);    
    longitude = 0.0;
    latitude = 0.0;        
}

int GPS::sample() {
    float time;
    char ns, ew, ns2, ew2, warning;
    int lock, timefix;

    while(1) {        
        getline();

        // Check if it is a GPGGA msg (matches both locked and non-locked msg)
 if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d", &time, &latitude, &ns, &longitude, &ew, &lock) >= 1) 
        { 
           if(!lock)
           {
             longitude = 0.0;
               latitude = 0.0;        
                return 0;
            } else 
            
           {
               if(ns == 'S') {    latitude  *= -1.0; }
               if(ew == 'W') {    longitude *= -1.0; }
               float degrees = trunc(latitude / 100.0f);
               float minutes = latitude - (degrees * 100.0f);
               latitude = degrees + minutes / 60.0f;
               degrees = trunc(longitude / 100.0f );         
              // Edit:original GPS.h had, degrees = trunc(longitude/100.f*0.01f);
               minutes = longitude - (degrees * 100.0f);
               longitude = degrees + minutes / 60.0f;
               return 1;
            }
       }
        else
        {                                       
if (sscanf(msg, "GPRMC,%d,%c,%f,%c,%f,%c,%f,%f", &timefix,&warning,&lat,&ns2,&lon,
                        &ew2,&speedgnd,&course) >=1)       

 {
           if(ns == 'S') {lat *= -1.0;}
           if(ew == 'W') { lon *= -1.0;}
           float deg = trunc( lat/100.0f);
           float min= lat - (deg*100.0f);
           lat = deg + min/60.0f;
deg = trunc(lon/100.0f); // This line too maybe should have had (lon/100.0f*0.0f);
           min= lon - (deg*100.0f);
           lon = deg + min/60.0f;
           
           return 1;
                  
        }        
        }
        
    }
}

float GPS::trunc(float v) {
    if(v < 0.0) {                        // floor(x) returns the largest integer value not greater than x.
        v*= -1.0;
        v = floor(v);
        v*=-1.0;
    } else {
        v = floor(v);
    }
    return v;
}

void GPS::getline() {
    while(_gps.getc() != '$');    // wait for the start of a line
    for(int i=0; i<256; i++) {
        msg[i] = _gps.getc();
        if(msg[i] == '\r') {
            msg[i] = 0;
            return;
        }
    }
    error("Overflowed message limit");
}

Main.cpp: 

#include "mbed.h"
#include "GPS.h"

Serial pc(USBTX, USBRX);
GPS gps(p9, p10);

int main() {
    while(1) {
        if(gps.sample()) {
            pc.printf(" GPGGA says: I'm at %f, %f\r\n", gps.longitude, gps.latitude);
            pc.printf("GPRMC says: I am at %f, %f\r\n", gps.lon, gps.lat);
  pc.printf("Speed over ground: %f, Course over ground: %f \r\n\r", gps.speedgnd, gps.course);
            pc.printf("\r\n");           
        } else {
            pc.printf("Oh Dear! No lock :(\n");
        }
    }
}