• Une arduino (dans mon cas une UNO basique)
• un ProtoShield pour arduino
• GPS Chip Set EM-411 http://www.dealextreme.com/p/em-411-gps-engine-board-module-with-sirf-star-iii-chipset-80037?item=2

Le module GPS discute en liaison série simple.

Alimenté, il envoie des trames sans cesses.

le but est de récupérer cette trame

#include <NewSoftSerial.h>
 
NewSoftSerial GPS =  NewSoftSerial(2, 3);
 
void setup()
{
  GPS.begin(4800);
  Serial.begin(9600);
}
void loop()
{
  char someChar = GPS.read();
 
  Serial.print(someChar,BYTE);
  delay(100);
 
}

• Résultat sur une serie

$GPGGA,184830.000,4451.8758,N,00033.6537,W,1,07,1.2,22.9,M,49.7,M,,0000*7E
$GPGSA,A,3,30,25,31,14,29,12,02,,,,,,1.8,1.2,1.3*33
$GPGSV,2,1,08,29,85,102,26,25,61,073,34,31,58,297,26,12,19,090,24*73
$GPGSV,2,2,08,14,19,222,17,30,18,289,26,02,18,044,14,21,16,170,*79
$GPRMC,184830.000,A,4451.8758,N,00033.6537,W,0.41,5.71,150512,,,A*7F

#include <SoftwareSerial.h>
 
SoftwareSerial GPS = SoftwareSerial(2,3);
 
int byteGPS=-1;
char linea[300] = "";
char comandoGPR[7] = "$GPRMC";
int cont=0;
int bien=0;
int conta=0;
int indices[13];
 
 
void setup(){
  GPS.begin(4800);
  Serial.begin(115200);
}
 
void loop(){
   byteGPS=GPS.read();         // Read a byte of the serial port
   if (byteGPS == -1) {           // See if the port is empty yet
     delay(100); 
   } else {
     linea[conta]=byteGPS;        // If there is serial port data, it is put in the buffer
     conta++;                      
     Serial.print(byteGPS, BYTE); 
     if (byteGPS==13){            // If the received byte is = to 13, end of transmission
//       digitalWrite(ledPin, LOW); 
       cont=0;
       bien=0;
       for (int i=1;i<7;i++){     // Verifies if the received command starts with $GPR
         if (linea[i]==comandoGPR[i-1]){
           bien++;
         }
       }
       if(bien==6){               // If yes, continue and process the data
         for (int i=0;i<300;i++){
           if (linea[i]==','){    // check for the position of the  "," separator
             indices[cont]=i;
             cont++;
           }
           if (linea[i]=='*'){    // ... and the "*"
             indices[12]=i;
             cont++;
           }
         }
         Serial.println("");      // ... and write to the serial port
         Serial.println("");
         Serial.println("---------------");
         for (int i=0;i<12;i++){
           switch(i){
             case 0 :Serial.print("Time in UTC (HhMmSs): ");break;
             case 1 :Serial.print("Status (A=OK,V=KO): ");break;
             case 2 :Serial.print("Latitude: ");break;
             case 3 :Serial.print("Direction (N/S): ");break;
             case 4 :Serial.print("Longitude: ");break;
             case 5 :Serial.print("Direction (E/W): ");break;
             case 6 :Serial.print("Velocity in knots: ");break;
             case 7 :Serial.print("Heading in degrees: ");break;
             case 8 :Serial.print("Date UTC (DdMmAa): ");break;
             case 9 :Serial.print("Magnetic degrees: ");break;
             case 10 :Serial.print("(E/W): ");break;
             case 11 :Serial.print("Mode: ");break;
             case 12 :Serial.print("Checksum: ");break;
           }
           for (int j=indices[i];j<(indices[i+1]-1);j++){
             Serial.print(linea[j+1]); 
           }
           Serial.println("");
         }
         Serial.println("---------------");
       }
       conta=0;                    // Reset the buffer
       for (int i=0;i<300;i++){    //  
         linea[i]=' ';             
       }                 
     }
   }
}

• Exemple sur une série

---------------
Time in UTC (HhMmSs): 184830.000
Status (A=OK,V=KO): A
Latitude: 4451.8758
Direction (N/S): N
Longitude: 00033.6537
Direction (E/W): W
Velocity in knots: 0.41
Heading in degrees: 5.71
Date UTC (DdMmAa): 150512
Magnetic degrees: 
(E/W): 
Mode: A