Compass confusion?

Discussion in 'Mavic Pro Help' started by thefrisbee995, Nov 4, 2016.

  1. thefrisbee995

    thefrisbee995 Well-Known Member

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    I've heard all sorts from people saying that compass and gimbal need calibration every time before flight in all sorts of scenarios. When is the right time to actually calibrate both of these (if at all necessary)?


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  2. kmaluo

    kmaluo Well-Known Member

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    Short answer, compass only once in open field, no metal around. Gimbal as needed for tilted horizon issue.
     
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  3. getoutandplay

    getoutandplay Active Member

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    I calibrate my compass before every flight to be safe. But have only been prompted to recalibrate if I have moved the Mavic a good distance from last flight or if it has been in my backpack and I have been on the bike.
     
  4. kmaluo

    kmaluo Well-Known Member

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    Not a good idea. Your compass needs a good baseline in idea conditions for the natural surrounding terrain. Look for Msinger and his compass calibration guide.
     
  5. getoutandplay

    getoutandplay Active Member

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    Didn't Msinger's info really just come from Ianwood's post? Both only say not to calibrate if there could be interference when doing so. But that seems fairly obvious to me because the point of calibration is to eliminate compass errors.
     
  6. 4wd

    4wd Well-Known Member

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    You can view the 'state' of calibration in the app.
    There's no need to keep re-doing it even if you drive 100s of miles it will still be near enough most likely.
    Every time you recalibrate there's a chance the new setting will be affected by something you aren't aware of.
    If things have gone wildly out because it was accidentally near a magnet (e.g. speaker) the app will tell you in fact won't let you start.
     
  7. kmaluo

    kmaluo Well-Known Member

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    Yeah I was too lazy to find who he was qouting. But it does basically say, callibrate one good time and leave it. You start calibrating all the time and happen to miss the rebar, pipe underground, car in the corner, power lines behind you, keys or phone in your pocket, then you might get into trouble once the craft gains altitude and the surrounding magnetic signature has changed.
     
  8. djv

    djv Member

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    Got mine last week...it hasnt prompted me to calibrate yet....am I missing something?
     
  9. thefrisbee995

    thefrisbee995 Well-Known Member

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    No, I think a lot of people are calibrating it excessively by the sound it.
     
  10. tooFLYforayoungGUY

    tooFLYforayoungGUY Active Member

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    Just traveled from Phoenix, where my drone was first flown, to Dallas TX. When I tried to get this bird In the air, the compass calibration came up, but also mag interference. My guess is this hotel parking lot has rebar and even a few feet above the ground, the compasses are just confused. Headed out to a park tomorrow to minimize my chances of interference.


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  11. Andart

    Andart Well-Known Member

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    Manual actually said do not calibrate unless asked.
    I think there are loads of problems caused by calibrating compass badly and then mavic fighting between GPS and a compass that is disagreeing

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  12. Anthony

    Anthony Well-Known Member

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    I have never calibrated the compass. .. and only had to do the gimbal once so far ...
     
  13. f3honda4me

    f3honda4me Well-Known Member

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    Per the manual, calibrate only if it tells you. The mavic is not like old drones where you have to calibrate compass if you fly in a different location.
     
  14. Scapegoat

    Scapegoat Well-Known Member

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    Flown mine 3 times since receiving , haven't calibrated anything yet. FW update & charge, that's it .
     
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  15. bakerboy

    bakerboy Well-Known Member

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    Calibrated once when I got it, and haven't touched it since. As per the manual there is no need to do it but a lot of old dji fliers will tell you that you must every flight (but give no explanation why they do it for the mavic when the manual says otherwise ;) ) These same dji only folk also reckon you should calibrated if stored near a sub-woofer but again can't give a reason. It's no different to transporting in a car, in a big metal box, the mavic doesn't care about the magnetic fields around it whilst it's off, because the FC had no idea because it isn't on

    I have driven several hundred kilometers from one launch to another and not calibrated, because A) it didn't need it and B) if the mavic doesn't have auto declination to account for the change in magnetic field I'll be very very surprised
     
  16. BudWalker

    BudWalker Well-Known Member

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    The Mavic doesn't discover or compensate for geomagnetic declination during compass calibration. And, neither does the P3. It's impossible for geomagnetic declination to be discovered. The compass calibration procedure (the "compass dance") can't provide the data necessary to determine geomagnetic declination. A necessary step would be something like precisely aligning the AC along true north and then tell the AC that it's aligned true north. For the same reason the compass calibration can not discover, know about, or compensate for local or regional geomagnetic distortions.

    The purpose of the calibration is to measure and compensate for magnetic distortions caused by the AC itself. Ideally, this would be done by placing the AC in every possible orientation in a uniform magnetic field. But, using the geomagnetic field as that uniform magnetic field and the compass dance are good enough. All that's really required is that, within the confines of the dance, the geomagnetic field isn't distorted and it's strength isn't drastically different from the flight location. The strength criteria is the reason that a calibration may be required when the location is changed. The difference in strength criteria is much looser with the Mavic than it is with the P3. That's why the Mavic can be calibrated at the factory in China and not require a calibration out of the box.

    I once did an experiment with my P3 where it was calibrated upside down; the horizontal step was upside down and the vertical step the AC was pointed up instead of down. Flew fine; it didn't try to fly upside down back to China.:)

    I haven't calibrated my Mavic and don't intend to unless the it tells that it's necessary. I figure it's a whole lot smarter than I am.
     
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  17. bakerboy

    bakerboy Well-Known Member

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  18. BudWalker

    BudWalker Well-Known Member

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    What I'm saying is that the declination can not be determined from the compass calibration procedure that the Mavic uses. The article you quoted computes the declination from the GP coords and has nothing to do with the compass calibration.
     
  19. bakerboy

    bakerboy Well-Known Member

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    Never said you could get declination from calibration
     
  20. BudWalker

    BudWalker Well-Known Member

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    I agree you didn't say that. That's why I didn't quote your post.
     
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