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Compass calibration issue

Discussion in 'Inspire 1 Discussion' started by Ilmakuvausorg, Apr 21, 2015.

  1. Ilmakuvausorg

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    It is, of course, needed to calibrate the copass when you go to a new flying location, however, what is the approx. distante from previous to be a "new" location? If I fly in one spot, land and walk 200 meter with the I1 is it then in a new location? Probably not, but if I drive 500 meter or 2 kilometer, or 10 kilometer...? Any thoughts on this?
     
  2. John Alan

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    Personally.. I use a 5 mile (or 8 kilometer) value to judge if it's "new"
     
  3. The Editor

    The Editor Moderator
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    Drove 250 miles yesterday, flew 5 packs, no compass calibration. Drove home in the evening.
    I only EVER do compass calibration if the mod values are outside of the recommended range of 1400-1600 or the app tells me I need to Calibrate (which has never happened) or if I was flying to a different country where the magnetic declination was vastly different.
     
  4. m00se

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    I was going to ask the same question as the OP,
    now I will ask a different one, does the I1 know the declination values of different locations or does it literally just build a reference field during the calibration and use that ?
     
  5. The Editor

    The Editor Moderator
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    No, it has no idea of the declination values wherever it is in the world. What you are doing when you do the compass dance is giving it a reference to work on. The danger (in my opinion) of doing the 'dance' every time you walk across the road is you have no idea whether that 'dance' is a good one. It maybe skewed by a manhole cover you didn't see or something similar. When you get airborne you will be free from that object that caused the bad calibration and working on the true declination factor. I find it far more reliable to calibrate in a known good location that I have used fo the past two years and leave it at that.
    I ALWAYS check my IMU and compass mod values before EVERY take-off (between batteries etc) and if ANY of them are not right I will not take off.

    It is a practice that has served me well and I see no reason to change it.

    That's just my technique... It works for me but obviously everyone needs to make up their own mind. :)
     
  6. DCGOO

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    The calibration corrects for a large change in declination angle (difference between true north and magnetic north. This will happen when moving a fairly large distance east or west. Generally that means the next time zone, or a couple hundred miles. Moving north or south has far less of an effect.