Does needing advanced IMU recalibration mean a bad Phantom?

Discussion in 'Specific Models of Quadcopters and Drones' started by Dave Austin, Jan 13, 2014.

  1. Dave Austin

    Dave Austin New Member

    Hi Folks,

    A guy just purchased my Phantom V1 but could not get GPS to calibrate after unboxing it and attempting to in the field. It would not start the props up either.

    Anyway, he called me and I drove over, picked it up, brought it home and after I did an an advanced IMU calibration, it immediately started up, calibrated, locked in, and flys fine. The props not starting up was not surprising since DJI says if "sensor error is too big, the system will not work".

    HOWEVER, he now tells me that he has "lost confidence" in it because it had to have the recalibration. I explained to him that any precision instrument needs to be recalibrated at times, but he is adamant that the Phantom is now unreliable.

    So... I'm short on reasons why IMU would need to be recalibrated. Is it because I traveled from NY to Florida which is where I dropped the Phantom off to him at?

    It wasn't dropped or treated roughly. Adult owned and operated, named "Betsy" and cared for gingerly. Only one IMU calibration done the first week I owned it (three months ago) and has approx. 30-40 hours of unremarkable (except for great videos!) flight time.

    Do you think there's any reason to be suspicious of the Phantom's future performance?

    Thanks much for any input.
     
    Dave Austin, Jan 13, 2014
    #1
  2. IceFyre13th

    IceFyre13th Guest

    In a nut shell, NY to FL is a long distance......satellites are in a different place in the sky, magnetic north is in a different location.......so yes the GPS needs to re-learn where it is and calibrate to the new location.

    Even my Garmin has a hard time when I have it on at home, turn it off and drive 100 miles away....turn it on there and it takes forever to figure out where I am now.....it all has to do with everything (satellites, magnetic fields, etc.) being in a different location.

    Anyway, just for general use its a good idea to recalibrate the system.
     
    IceFyre13th, Jan 14, 2014
    #2
  3. Dave Austin

    Dave Austin New Member


    Thank you for the reply.
     
    Dave Austin, Jan 14, 2014
    #3
  4. webman

    webman Administrator Staff Member

    Make sure he watches the video and does the Compass re-calibration also! That should be done once in a while anyway, and must be done when you have moved it a distance!

    http://wiki.dji.com/en/index.php/Phantom-GPS_%26_Compass_Calibration

    DJI makes it clear:
    "The GPS module has a built-in magnetic field sensor for measuring the geomagnetic field, which is not the same in different areas. The GPS module will not work unless the Compass Module has been connected. Make sure to the Compass Module connections is correct."

     
    webman, Jan 14, 2014
    #4
  5. Dave Austin

    Dave Austin New Member

    Thank you, webman.
     
    Dave Austin, Jan 14, 2014
    #5
  6. Tom Wolves

    Tom Wolves New Member

    What is advanced IMU? Or what does it mean? Thank you for your time.
    T.W.
     
    Tom Wolves, Feb 11, 2014
    #6
  7. Tom Wolves

    Tom Wolves New Member

    Never mind, I looked up IMU (inertial measurement unit) in the glossery.
     
    Tom Wolves, Feb 12, 2014
    #7

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