using GPS

[basha gajula]

How to use GPS which comes with dragonfly board. can we get AT commands set for dragonfly

[Steve Kovarik]

Hello Basha

You would need to interface an active GPS antenna to the “G” U.FL
interface on the modem, and place the GPS antenna where it has a clear
vies of the sky.

at$gpsnmun=1,1,0,0,0,0,0 (enable unsolicited messages)
at$gpsp=1 (start GPS receiver in standalone mode)

After a time, a continuous streaming of GGA sentences are sent to the modem
serial interface.

at$gpsnmum=0,1,0,0,0,0,0 (Stop streaming of GGA sentences)

at$gpsacp (get latest GPS coordinates)

at$gpsp=0 (Turn off GPS receiver)

Link to manual
http://www.multitech.com/manuals/telit_3g_modules_at_commands_reference_guide_r9.pdf

-Best Regards

[Mike Fiore]

Basha,

There is also a GPS API in the MTSAS library on mbed.

    /** Enables GPS.
    * @returns true if GPS is enabled, false if GPS is not supported.
    */
    virtual bool GPSenable();
 
    /** Disables GPS.
    * @returns true if GPS is disabled, false if GPS does not disable.
    */
    virtual bool GPSdisable();
 
    /** Checks if GPS is enabled.
    * @returns true if GPS is enabled, false if GPS is disabled.
    */
    virtual bool GPSenabled();
        
    /** Get GPS position.
    * @returns a structure containing the GPS data field information.
    */
    virtual gpsData GPSgetPosition();
 
    /** Check for GPS fix.
    * @returns true if there is a fix and false otherwise.
    */
    virtual bool GPSgotFix();

The library can be found here: https://developer.mbed.org/teams/MultiTech/code/mtsas/

Cheers,

Mike

[Michael Schwerin]

I am having trouble getting the GPS API to work. After the cellular system is connected and PPP link is established I do the following:

1. if GPSenabled() is false I call GPSenable()
2. wait until GPSenabled() returns true.
3. Start calling GPSgotFix() every 5 seconds waiting for a fix but never get one.

On the first call of GPSgotFix() I get the following error over the debug serial port:
[ERROR] Expected 11 fields but there are 0 fields in “”

My cell phone could see 19 satellites and was using 10 in the same location. Two different GPS antennas were tried.

[Vivek Ratna Kansakar]

I am also having similar problems with the GPS API. I am having difficulty in getting the GPS fix.

if(! radio->GPSenabled())
{
 if(radio->GPSenable())
 {
  logInfo("Checking for GPS fix.");
  if(radio->GPSgotFix())
  {
   displayGpsData();
  }
  else
  {
   logInfo("No GPS fix.");
  }
 }
 else
 {
  logError("Error in enabling GPS.");
 }
}

The displayGpsData() method prints out the number of satellites, latitudes & longitudes.

• This reply was modified 7 years, 6 months ago by Vivek Ratna Kansakar.

[Vivek Ratna Kansakar]

Hi,

I solved my problem. The GPS antenna needs to be place in an open space with no roofs where it can pick up satellite signals (at least 3 satellites should be detected).

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