hey i used this code for gps sim908 ,it works but i have problem ,the location of latitude and longitude are far from my location by few KM but i want to get the exact location.
int8_t answer;
int onModulePin= 13;
int counter;
long previous;
char aux_string[30];
char data[100];
int data_size;
int x = 0;
char N_S,W_E;
char frame[200];
char latitude[15];
char longitude[15];
char altitude[6];
char date[16];
char time[7];
char satellites[3];
char speedOTG[10];
char course[10];
void setup(){
pinMode(onModulePin, OUTPUT);
Serial.begin(115200);
Serial.println("Starting...");
power_on();
delay(3000);
// sets the PIN code
//sendATcommand("AT+CPIN=****", "OK", 2000);
//sendATcommand("AT+CPIN?", "READY", 500);
delay(3000);
// sets APN, user name and password
sendATcommand("AT+CGPSPWR=1", "OK", 2000);
sendATcommand("AT+CGPSRST=1", "OK", 2000);
delay(1000);
// waits for fix GPS
while( (sendATcommand("AT+CGPSSTATUS?", "2D Fix", 5000) ||
sendATcommand("AT+CGPSSTATUS?", "3D Fix", 5000)) == 0 );
// Basic
// Clean the input buffer
sendATcommand("AT+CGPSINF=0", "AT+CGPSINF=0\r\n\r\n", 2000);
counter = 0;
answer = 0;
memset(frame, '\0', 100); // Initialize the string
previous = millis();
// this loop waits for the NMEA string
do{
if(Serial.available() != 0){
frame[counter] = Serial.read();
counter++;
// check if the desired answer is in the response of the module
if (strstr(frame, "OK") != NULL)
{
answer = 1;
}
}
// Waits for the asnwer with time out
}
while((answer == 0) && ((millis() - previous) < 2000));
frame[counter-3] = '\0';
// Parses the string
strtok(frame, ",");
strcpy(longitude,strtok(NULL, ",")); // Gets longitude
strcpy(latitude,strtok(NULL, ",")); // Gets latitude
strcpy(altitude,strtok(NULL, ".")); // Gets altitude
strtok(NULL, ",");
strcpy(date,strtok(NULL, ".")); // Gets date
strtok(NULL, ",");
strtok(NULL, ",");
strcpy(satellites,strtok(NULL, ",")); // Gets satellites
strcpy(speedOTG,strtok(NULL, ",")); // Gets speed over ground. Unit is knots.
strcpy(course,strtok(NULL, "\r")); // Gets course
convert2Degrees(latitude);
convert2Degrees(longitude);
Serial.println("*************************************************");
Serial.print(" Longitude: ");
Serial.println(longitude);
Serial.print("Latitude: ");
Serial.println(latitude);
sendATcommand("AT+CGPSPWR=0", "OK", 2000);
}
void loop(){
}
void power_on(){
uint8_t answer=0;
// checks if the module is started
answer = sendATcommand("AT", "OK", 2000);
if (answer == 0)
{
// power on pulse
digitalWrite(onModulePin,LOW);
delay(3000);
digitalWrite(onModulePin,HIGH);
// waits for an answer from the module
while(answer == 0){
// Send AT every two seconds and wait for the answer
answer = sendATcommand("AT", "OK", 2000);
}
}
}
int8_t sendATcommand(char* ATcommand, char* expected_answer1,
unsigned int timeout)
{
uint8_t x=0, answer=0;
char response[100];
unsigned long previous;
memset(response, '\0', 100); // Initialize the string
delay(100);
// Clean the input buffer
while( Serial.available() > 0) Serial.read();
Serial.println(ATcommand); // Send the AT command
x = 0;
previous = millis();
// this loop waits for the answer
do{
if(Serial.available() != 0){
response[x] = Serial.read();
x++;
// check if the desired answer is in the response of the module
if (strstr(response, expected_answer1) != NULL)
{
answer = 1;
}
}
//Waits for the asnwer with time out
}while((answer == 0) && ((millis() - previous) < timeout));
return answer;
}
int8_t convert2Degrees(char* input){
float deg;
float minutes;
boolean neg = false;
//auxiliar variable
char aux[10];
if (input[0] == '-')
{
neg = true;
strcpy(aux, strtok(input+1, "."));
}
else
{
strcpy(aux, strtok(input, "."));
}
// convert string to integer and add it to final float variable
deg = atof(aux);
strcpy(aux, strtok(NULL, '\0'));
minutes=atof(aux);
minutes/=1000000;
if (deg < 100)
{
minutes += deg;
deg = 0;
}
else
{
minutes += int(deg) % 100;
deg = int(deg) / 100;
}
// add minutes to degrees
deg=deg+minutes/60;
if (neg == true)
{
deg*=-1.0;
}
neg = false;
if( deg < 0 ){
neg = true;
deg*=-1;
}
float numeroFloat=deg;
int parteEntera[10];
int cifra;
long numero=(long)numeroFloat;
int size=0;
while(1){
size=size+1;
cifra=numero%10;
numero=numero/10;
parteEntera[size-1]=cifra;
if (numero==0){
break;
}
}
int indice=0;
if( neg ){
indice++;
input[0]='-';
}
for (int i=size-1; i >= 0; i--)
{
input[indice]=parteEntera[i]+'0';
indice++;
}
input[indice]='.';
indice++;
numeroFloat=(numeroFloat-(int)numeroFloat);
for (int i=1; i<=6 ; i++)
{
numeroFloat=numeroFloat*10;
cifra= (long)numeroFloat;
numeroFloat=numeroFloat-cifra;
input[indice]=char(cifra)+48;
indice++;
}
input[indice]='\0';
}
