I saw a tuttorial that IMU and compass calibrations done with mavic folded!!!!This is WRONG because you have 4 metal motors near the craft so it affects callibration with  negative results!!!!!!Pleace correct the tutorial!!!

Is this the video you're referring to, ?

Ahhhhhhhh

Wrong. It needs to be done with the arms folded. Then the aircrafts body is level.  Which it needs to be for IMU. Soooo... STOP SCREAMING

When performing these calibrations it shows you that IMU is done when folded and for compass calibration it is unfolded. All of this is displayed on the app itself while you do it.

Think that may effect compass cal but not IMU.

Think fist you have 4 motors with coils which a small amount of electricity come in which creates an magnetic field which is closer to the body of the aircraft that causes malfunction to the calibration process when drone is folded as the above video.....If you unfolded the motors are away from the body and the magnetic field is weaker.Keep in mind that a small amount of electricity have the motors even if the propeller not spins.....In my opinion the above tutorial is wrong and thats the problem to all erratic behavior....Maybe a DJI expert tell to us if this is true....

KonsKall Posted at 2016-11-7 09:51
Think fist you have 4 motors with coils which a small amount of electricity come in which creates an ...

You are confusing compass calibration with IMU calibration.  This is very true for compass calibration.  IMU stands for Internal Measurement Unit (ie accelerometers).

Don't take this to hart ...

how often do you IMU Compass Calibration  the mavic

roblor@optusnet Posted at 2016-11-7 18:20
how often do you IMU Compass Calibration  the mavic

This might help how IMU works.

IMU "Inertial measurement unit"
This was not written by me , but was an answer to a question I posed.
As far as I see it, IMU calibration on a level surface updates a table of values the flight controller software uses as a reference for a level stationary hover. From there the craft responds predictably to flight commands.  It also likely measures any sensor noise and thermal drift so that these technical imperfections are accounted for when using IMU sensor data in flight. - this is likely why there must be no vibrations during the calibration process.


Bad IMU calibration could cause drift and attitude issues as the flight controller fights to hold the craft in what it thinks is the correct attitude as opposed to the correct physical attitude.


The IMU usually has 2 types of sensors – angle and acceleration and in turn 3 sensors of each type measuring in the X,Y and Z axis. These sensors can, through vibration, aging, impact etc, drift in their response over time and thus an IMU calibration will establish a new reference for the IMU’s level/stationary state that the flight controller can work with to restore stable flight.


Think of calibration as the bringing back into line the measured craft attitude with the true physical craft attitude.


As to how often an IMU calibration is needed, I wouldn’t like to say; certainly after any impact or if there are suspicions the craft can’t hover in a level attitude in a windless environment. Also after a firmware update is a good opportunity just in case the stored values get corrupted or are incompatible with the later firmware.

I did put this piece together because at least 1 person seemed to have a problem, I think Bad IMU.

Its also good to mention that the IMU is the reason why you are able to shut off the motors using just the throttle down command when on the ground. The IMU reads that the aircraft is unable to move any further, and after three seconds it determines that is has officially landed and can shut off the motors safely.

qMvQTfjUrm4z Posted at 2016-11-7 17:59
You are confusing compass calibration with IMU calibration.  This is very true for compass calibra ...

Inertial Measurement Unit.

hallmark007 Posted at 2016-11-7 11:26
Inertial Measurement Unit.

Brain fart on my part.  Thought it right, typed it wrong.  Thanks for the correction!

qMvQTfjUrm4z Posted at 2016-11-7 19:41
Brain fart on my part.  Thought it right, typed it wrong.  Thanks for the correction!

No problem, thought it was a typo..

When calibrating compass, it's unfolded, you could check it in the manual or the notice on the APP.
When calibrating IMU, please put it in a level surface when it's folded.