Trying to use UBX on an BE-880 gps chip in Arduino

Projects Networking, Protocols, and Devices
1

So I've been trying to first disable any NMEA messages and instead run NAV-POSLLH messages instead for the Be-880 GPS chip by writing byte values to the chip. My problem is that when I run the second function I have none of the messages come back to the Arduino from the chip. I've been working on this for a weeks now and nothing I do fixes it.

#include <SoftwareSerial.h>

// Connect the GPS RX/TX to arduino pins 3 and 5
SoftwareSerial serial = SoftwareSerial(3,5);

const char UBLOX_INIT[] PROGMEM = {
  // Disable NMEA
  0xB5,0x62,0x06,0x01,0x08,0x00,0xF0,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x00,0x24, // GxGGA off
  0xB5,0x62,0x06,0x01,0x08,0x00,0xF0,0x01,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x2B, // GxGLL off
  0xB5,0x62,0x06,0x01,0x08,0x00,0xF0,0x02,0x00,0x00,0x00,0x00,0x00,0x01,0x02,0x32, // GxGSA off
  0xB5,0x62,0x06,0x01,0x08,0x00,0xF0,0x03,0x00,0x00,0x00,0x00,0x00,0x01,0x03,0x39, // GxGSV off
  0xB5,0x62,0x06,0x01,0x08,0x00,0xF0,0x04,0x00,0x00,0x00,0x00,0x00,0x01,0x04,0x40, // GxRMC off
  0xB5,0x62,0x06,0x01,0x08,0x00,0xF0,0x05,0x00,0x00,0x00,0x00,0x00,0x01,0x05,0x47, // GxVTG off

  // Disable UBX
  0xB5,0x62,0x06,0x01,0x08,0x00,0x01,0x07,0x00,0x00,0x00,0x00,0x00,0x00,0x17,0xDC, //NAV-PVT off
  0xB5,0x62,0x06,0x01,0x08,0x00,0x01,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x12,0xB9, //NAV-POSLLH off
  0xB5,0x62,0x06,0x01,0x08,0x00,0x01,0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x13,0xC0, //NAV-STATUS off

  // Enable UBX
  //0xB5,0x62,0x06,0x01,0x08,0x00,0x01,0x07,0x00,0x01,0x00,0x00,0x00,0x00,0x18,0xE1, //NAV-PVT on
  0xB5,0x62,0x06,0x01,0x08,0x00,0x01,0x02,0x00,0x01,0x00,0x00,0x00,0x00,0x13,0xBE, //NAV-POSLLH on
  //0xB5,0x62,0x06,0x01,0x08,0x00,0x01,0x03,0x00,0x01,0x00,0x00,0x00,0x00,0x14,0xC5, //NAV-STATUS on

  // Rate
  0xB5,0x62,0x06,0x08,0x06,0x00,0x64,0x00,0x01,0x00,0x01,0x00,0x7A,0x12, //(10Hz)
  0xB5,0x62,0x06,0x08,0x06,0x00,0xC8,0x00,0x01,0x00,0x01,0x00,0xDE,0x6A, //(5Hz)
  0xB5,0x62,0x06,0x08,0x06,0x00,0xE8,0x03,0x01,0x00,0x01,0x00,0x01,0x39, //(1Hz)
};

void setup()
{
  serial.begin(9600);

  // send configuration data in UBX protocol
  for(int i = 0; i < sizeof(UBLOX_INIT); i++) {                        
    serial.write( pgm_read_byte(UBLOX_INIT+i) );
    delay(5); // simulating a 38400baud pace (or less), otherwise commands are not accepted by the device.
  }
}

void loop() {}
'''
The function below is supposed to print out the NAV-POSLLLH messages I want to the serial monitor but nothing is happening. When going through the code I found that the checksum function isn't working but I'm not sure why. 

'''
#include <SoftwareSerial.h>

// Connect the GPS RX/TX to arduino pins 3 and 5
SoftwareSerial serial = SoftwareSerial(3,5);

const unsigned char UBX_HEADER[] = { 0xB5, 0x62 };

struct NAV_POSLLH {
  unsigned char cls;
  unsigned char id;
  unsigned short len;
  unsigned long iTOW;
  long lon;
  long lat;
  long height;
  long hMSL;
  unsigned long hAcc;
  unsigned long vAcc;
};

NAV_POSLLH posllh;

void calcChecksum(unsigned char* CK) {
  memset(CK, 0, 2);
  for (int i = 0; i < (int)sizeof(NAV_POSLLH); i++) {
    CK[0] += ((unsigned char*)(&posllh))[i];
    CK[1] += CK[0];
  }
}

bool processGPS() {
  static int fpos = 0;
  static unsigned char checksum[2];
  const int payloadSize = sizeof(NAV_POSLLH); //32

  while ( serial.available() ) {
    byte c = serial.read();
    byte t = UBX_HEADER[fpos];
    if ( fpos < 2 ) {
      if ( c == t )
        fpos++;
      else
        fpos = 0;
    }
    else {
      if ( (fpos-2) < payloadSize ) {
        ((unsigned char*)(&posllh))[fpos-2] = c;
      }
      fpos++;
      if ( fpos == (payloadSize+2) ) {
        calcChecksum(checksum);
      }
      else if ( fpos == (payloadSize+3) ) {
        Serial.println(c);
        byte y = checksum[0];
        Serial.println(y);
        if ( c != y) {
          fpos = 0;
        }
      }
      else if ( fpos == (payloadSize+4) ) {
        fpos = 0;
        byte l = checksum[1];
        if ( c == l ) {
          return true;
        }
      }
      else if ( fpos > (payloadSize+4) ) {
        fpos = 0;
      }
    }
  }
  return false;
}

void setup() 
{
  Serial.begin(9600);
  serial.begin(9600);
}

void loop() {
  if ( processGPS() ) {
    Serial.print("iTOW:");      Serial.print(posllh.iTOW);
    Serial.print(" lat/lon: "); Serial.print(posllh.lat/10000000.0f); Serial.print(","); 
    Serial.print(posllh.lon/10000000.0f);
    Serial.print(" height: ");  Serial.print(posllh.height/1000.0f);
    Serial.print(" hMSL: ");    Serial.print(posllh.hMSL/1000.0f);
    Serial.print(" hAcc: ");    Serial.print(posllh.hAcc/1000.0f);
    Serial.print(" vAcc: ");    Serial.print(posllh.vAcc/1000.0f);
    Serial.println();
  }
}
2

I moved your topic to an appropriate forum category @cgrammens22.

In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.

This is an important part of responsible forum usage, as explained in the "How to get the best out of this forum" guide. The guide contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

3

You have two times setup and two times loop in your sketch. That's not compiling.

4

When you send a command to the GPS, are you checking that the GPS responds that the command has been accepted OK ?

5

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.