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Clarification please

Discussion in 'General Discussion' started by CyberVet65, Jan 17, 2014.

  1. CyberVet65

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    In many of the "fly away" discussion I read about compass calibration. And I seem to find the "GPS Dance" confusing. I read that people calibrate the compass before every flight? I can only calibrate the compass using the software and the Phantom hooked to the computer.
    I understand the GPS calibration and what it does for the failsafe and rth modes but I don't understand compass calibration.
    Thanks
     
  2. Dave Pitman

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    Compass calibration is done before flying the Phantom. It is the "Compass calibration dance". Nothing to do with the GPS. For a gps lock, the Phantom should be left still in one spot until gps signal lock is signaled by the leds.

    Please do get a good understanding of all of this before flight. Not doing so could possibly lead to a user error induced fly away, which is far more likely than a Naza, or receiver error fly away.

    All of this is in the user manual.
    http://download.dji-innovations.com/dow ... ual_en.pdf

    Compass Calibration, DJI Phantom Wiki
    http://wiki.dji.com/en/index.php/Phanto ... alibration

    Compass Calibration Video
    http://www.youtube.com/watch?v=dcUYS77ZTeE
     
  3. CyberVet65

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    Got it! GPS is done automatically when the system gives me the green light. The compass calibration is specifically designed for the RTH function and Failsafe mode. Thanks
     
  4. Dave Pitman

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    The Flight controller (FC, Naza) uses gps possitioning in combination with the compass, or more correctly the "Magnetometer". The gps tells the FC "where" in 3d space it is located, but it (the FC) does not know which direction it is pointed if it is not moving. That is what the compass does. It tells the flight controller which way is magnetic North.

    If you have a gps lock, but your compass is not calibrated properly, the FC will most likely not be able stabilize the Phantom correctly, could possibly cause the "toilet bowl" death spiral, and will probably not be able to RTH or failsafe.

    This is not trivial stuff. Probably 90% of "fly aways" are caused by the pilot not truly understanding this stuff. Read the manual. and then read it again, and then ask more questions..really!