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Permalink Reply by Fête Mobile on March 22, 2012 at 1:30am

OK, I seem to have found a work-around. After powering up, the APM needs to be warm-booted (reset with the reset switch). Opening the CLI does this, and that seems to be why the GPS was working only in CLI mode. I'm not sure why it needs to be reset like this.

Also, darn if that reset switch isn't hard to reach with the way I've mounted the APM!

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Permalink Reply by Aleksey Kharlanov on March 22, 2012 at 1:47am

Maybe, GPS need some time to initialize when you power on board (Cold Start). So APM not see working GPS. When you doing reset (Warm start) your GPS already initialized and APM detected it.

 

Try to add mavlink_delay(250) in system.pde

 

    // Read in the GPS
        for (byte counter = 0; ; counter++) {

                g_gps->update();

                if (g_gps->status() != 0){

                        GPS_enabled = true;

                        break;

                }

if (counter >= 2) {
                        GPS_enabled = false;

                        break;

          }

          mavlink_delay(250);

        }

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Permalink Reply by Aleksey Kharlanov on March 24, 2012 at 6:13am

Ok. I have same issue. Also I can say, my code above will not works.

I'm connected my Logic Analyzer to see when GPS start to send any data on its COM port. And can say, cold start usually takes 2.5 sec. APM tried to initialize GPS after 1.5 sec after powering on, so at this moment GPS still not ready to accept commands.

So I'm moved GPS initialization after INS initialization (Gyro), it will give more time for GPS.

Try attached system.pde (2.5.1)

Attachments:

• system.pde, 17 KB

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