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GPS error

Discussion in 'Pro/Adv Discussion' started by fin032, Apr 2, 2016.

  1. fin032

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    My P3P has just been in for a new shell. The craft and app have also been updated since my last flight. Done the usual IMU, gimbal, rc stick and compass calibrations. Everything was fine for the first half of the test flight apart from a few weak signal warnings.

    As I was ascending to 200' I got a warning saying GPS error. The quad went in to atti mode so I brought it back down low. It had went back to GPS mode with in a few seconds and back to normal.

    When I had a look at the video at the same point in time the gimbal had dipped left and the right. I have had a look at healthy drones and can't see any problems to note apart from the rudder response seem slow. I then had a look at the flight on my tab and seen that at 8min 45sec the mode changed to atti for a few seconds but no warning came up. The battery percentage jumped from 50 to 57% at the same time.

    What do you guys think? Anything to worry about?

    Link to heathy drones

    HealthyDrones.com - Innovative flight data analysis that matters
     
  2. MrMcfly

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    If the Phantom receives less than 6 (???) satellite signals, it will switch to ATTI, because GPS is no longer being used.
    This happened for 6 seconds, so I was would not say it's a 'major' event. There's all kinds of reasons for the Phantom
    to lose satellite signal...

    A good test would be to fly in a different area to see if the GPS lock issue is area specific.
     
  3. fin032

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    Cheers for the reply MrMcfly. The quad showed 15+ sats for the full flight but yeah I will head back out today to see how I do at a different location.
     
  4. robinb

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    I would do a compass calibration just in case this is the cause.
     
  5. fin032

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    Will do Robin. If it plays up again I will also try to reinstall the craft firmware again.
     
  6. robinb

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    I had this once so did calibration and not had it since.
    I also did IMU cal at same time.
     
  7. fin032

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    Been out for a 2nd test flight after doing IMU and compass cal again. No GPS warning this time but still something no right. When yawing left or right after letting go of the sticks the phantom yaws back the opposite direction around 5 degrees every time. It's also gliding off to the right if I am attempting to fly in a straight line. I have to give it some left stick to keep it straight. The only error I am getting is a slow rudder response. I had turned the yaw gain setting down to there lowest point to get better panning shots. Do you think this could be part of the problem?

    Next on my list to try would be to downgrade the firmware and see how it flys.

    What do you guys think?
     
  8. robinb

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    You could try calibrating the RC as maybe that has a little stick input when it should be zero.
     
  9. BudWalker

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    Before downgrading the firmware why don't you try setting the yaw gain higher and see if that fixes the problem. If that works then at least you'll know what's causing the problem. It's unlikely that these problems are related to the firmware version.

    You should also take a look at either the .txt log or the .DAT log to make sure you don't have some stick input present that's causing the drifting. Either of these logs will have the necessary data. My favorite .txt log converter can be found here and my favorite .DAT converter can be found here.
     
  10. fin032

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    Cheers I will change the gains and try the sticks calibration. Will also have a look at the log files.