Discussions

"No GPS" Problem

Posted by Cody O. on May 14, 2012 at 2:32pm

So here's the issue:

My APM2.0 always has the 3DFix light go solid within a couple minutes, but quite frequently Mission Planner will display "No GPS" (and of course hdop:0 and sats:0) when connected via 3DR radios.  I can get the GPS to register by disconnecting Mission Planner, pressing the reset button on the APM2, and then reconnecting Mission Planner.  The GPS will keep its 3D Fix during the AMP2 reset.  Sometimes I need to do this more than once before "No GPS"  will turn into "No Fix" or "3D Fix" on Mission Planner.  Everything seems to work fine when connected via USB instead of radio.  All other sensors/telemetry work fine.  I am using Mission Planner 1.1.85 and ArduPlane 2.34, which are the current versions.

Does anyone know why Mission Planner fails to detect/read the GPS on my APM2.0?

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Replies

  • yassine March 25, 2014 at 3:29pm

    Hello,

    I have a problem to arm my Pixhawk, it is flashing blue (disarmed, searching for GPS. Autonomous, loiter, and return-to-launch modes require GPS lock).
    can you help me please 
    Thank you very much 
    • Gabor H > yassine January 11, 2016 at 5:43am

      Hi,

      I also have similar issue with Pixhawk.

      Any news how to use the GPS's compass when it is connected to I2C splitter board, and not directly to Pixhawk?
      Because I've only GPS fix when the compass cable of the GPS directly connected to the Pixhawk. If I connect compass to I2C spliiter, then no GPS fix. Or if the compass cable disconnected from the splitter board, then I also have GPS fix.

      Any idea how to use the I2C splitter board to give it power?
  • 100KM
    Hein du Plessis June 12, 2013 at 1:26am

    I finally solved my problem by powering the APM from my receiver to the input rail, bridging positive and negative over to the output rail AND using the APM power module, all with JP1 connected. It's the only scenario that allows my GPS to work.

  • Cody O. June 20, 2012 at 4:10pm

    "I was getting 5-7 sats consistently, but there was no lock.  9999hdp as well"

    "I really am out of ideas. 1.5+ hrs of 6-7 sats with no 3Dfix."

    Jonathan,

    It could be your environment.  At my office I get 10-11 satellites, but the location dances wildly up to 100m.  My best guess is that all the nearby sheet metal covered buildings are playing havoc on the GPS signal.  At my rural testing grounds it's another story; I get a fix good enough to track a 1m width walking path.  Try taking your bare APM2 to a different location and see if you get a lock then.

  • Cody O. June 15, 2012 at 8:00pm

    I believe I discovered the cause of my problem:

    I was powering the APM2 from a 5v 650mA linear regulator (even though the wiki says not to) since my ESC's BEC is 6v.  The regulator actually put out about 4.93v, which I think was under-powering the board.  Everything has been working great since I replaced the linear regulator with a 5v 3A BEC.

  • Dave W June 14, 2012 at 6:33am

    I have a very similar problem as Cody O. 

    GPS telemetry parameters works fine over USB but refuses to work over 3DR Radio.

    All other parameters like airspeed are fine.

    APM 2 with GPS shield, ArduPilot 2.34 (unmodified)
    3DR Radio kit (433 Mhz), SiK 1.5 on HM-TRP
    APM Planner 1.1.92 MavLink 0.9, Windows 7 Service Pack 1 x86

    1. Connect ESC to IN1 to power APM2 (bench testing)
    2. Switch on APM2 with 3DR Radio connected to UART 0/2(USB disconnected)
    3. Wait for solid blue light on GPS shield indicating GPS fix/lock.
    3. Open APM Planner and connect to APM2 using 3DR Radio
    4. View artificial horizon and status tab.

    GPS telemetry is not displayed in APM Planner.
    "NO GPS" is displayed.
    Status tab shows gpsstatus=0, gpshdop=0, satcount=0.

    Have tried flashing the radio firmware and all sorts of diffident orders of connect, start up and pressing the reset button.

    I've joined in with all this late (only recently bought APM2).

    This is the only problem I have come across so far.

  • Cody O. May 21, 2012 at 7:50am

    I think my issue is different from what you have, John and James.

    I ALWAYS get a 3D fix indicated on the APM2 within a couple minutes.  The problem is Mission Planner displays "No GPS" instead of "No Fix"/"3D Fix".  This issue is reliably fixed by waiting for the 3D Fix light to go solid, pressing the APM2 reset button, and reconnecting MAVLink on Mission Planner.

    This only occurs occasionally; sometimes everything works fine without the need to reset the board.  If I had to guess what the problem is, I'd say there's still a start sequence bug in ArduPlane 2.34, like Michael refers to.

  • Developer
    Michael Oborne May 15, 2012 at 4:35am

    make sure you have the latest firmware. re the reset bug

  • Moderator
    Dean Wynton May 15, 2012 at 1:17am

    Is it just the gps? sometimes when I am connected via mavlink I have to switch out of one tab into another tab and then back to show the correct data.

    You could try that and see if it makes a difference? I think it just needs refreshing sometimes..

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