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Compass module CANNOT work in the polar circle.

Discussion in 'Phantom 2 Discussion' started by auen1, Feb 26, 2015.

  1. auen1

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    I"m reading through the NAZA manual preparing for my first flight and came across this
    OK, so I'm a few hundred miles from the Arctic Circle.
    How can I tell if the compass is working?
    And can somebody tell me what are the limitations that cause the compass to NOT work?

    Thanks!
     
  2. landmannnn

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    Cannot is a bit strong. Magnetic errors can be pretty high in the arctic circle so the phantom may not function as designed.
    Bearing in mind that flying off in a random direction appears to be part of the design, probably not a bad thing.
     
  3. jumanoc

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    You can fly in ATTi mode or Manual Mode. No Compass or Bad compass readings affects RTH, HL, CL (IOC features).
    Test your readings after calibrating IMU. According to DJI, correct values are above 750 and below 2.250 better if it is between 1.000 and 1.700 after calibration.
     
  4. ianwood

    ianwood Taco Wrangler
    Staff Member

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    I've never flown in a polar region but this is what I would guess:

    • Calibrate the compass in every location you fly. Follow the primer viewtopic.php?f=4&t=32829
    • Look for signs of TBE (toilet bowl effect, circling).
    • Keep it close by until you are sure there is no TBE.
    • If the horizon on the gimbal is very bad, that is another indication of a bad compass reading.
    • Do not use RTH in case of TBE. Use ATTI to get it back.
     
  5. f1nutter

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    I recently flew in Muonio, northern Finland. It is at 67deg 57.5' North, approx 100 miles inside the Arctic circle and 1500 miles from the North Pole.

    I did a compass calibration before the first flight and didn't need to do it again. Everything worked brilliantly. I also use RTH when I lost line-of-sight in the clear blue sky.
     
  6. auen1

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    Alright, my IMU readings are 1,690 after recalibration. I did get a "high MC temp" message. Turned the bird off for 5 minutes and the IMU recalibration continued. Thought the warning was odd as I only had the battery on for about 5 minutes.

    That is good to know.

    Thank to all for the advice!
     
  7. ianwood

    ianwood Taco Wrangler
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    IMU and compass are two different systems. IMU should be calibrated as well but it should work as it would anywhere in the world. It is the compass that you need to be focused on when in polar regions.
     
  8. JTBernier

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    If you look at a declination map, you quickly realize why the polar circle is a challenge... but more so in some areas than others.

    Nome, AK isn't really too much of a challenge. Now if you were in Nunavut, it might be different :)

    http://maps.ngdc.noaa.gov/viewers/histo ... clination/
     
  9. auen1

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    Thanks JT,
    I see now what is going on with the compass.
    Your right, looks like I should not have any problems.
    Thanks for that link.
     
  10. AnselA

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    Location:
    Declination +8° 11'
    Muonio data:

    Latitude: 67° 56' 7.7" N
    Longitude: 23° 41' 21.4" E
    Magnetic declination: +10° 20'

    is a lot, but should not be a problem after DJI "fixed" the firmware in summer 2014...