Hi,
I am experiencing a slight drift on the yaw axis when flying in a straight line and want to recalibrate the compass.

The step by step guide in the Go app tells me first to hold the Mavic horizontally and rotate it and in the next step to turn it on the
left side and rotate it.
The manual says first horizontal and in the next step nose down and rotate.

I think I am experiencing the drift since I did the calibration the way the app told me...

Do you know whats the correct way to calibrate it?

Thanks

My version of the manual addresses this on page 50. According to the manual, rotate about the vertical axis (yaw) first, then point the nose down and rotate about longitudinal axis (roll). The DJI tutorial video found here corroborates this. Hope this helps.

I did nose down as per the manual, cant say what the app said as it was 30 feet away with the controller.
Just make sure you are well out in the open and away from any interference.
Once done correctly you should not have to do it again, unless you travel thousands of miles away.

Why would you need to calibrate the compass, did you get a warning? Drifting like that is not caused by compass, it would be more likely your IMU needs calibrating.

This might help you understand, good luck..

IMU "Inertial measurement
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.



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.

Thanks for your help guys.
So it looks like nose down is right...

Maybe "drift" was the wrong word: The Mavic is slightly rotating to the left when I try to fly in a straight line. For me that sounds like
the compass needs to be calibrated.
I did the calibration because people in this forum mentioned that the factory calibration was done some thousand miles away from the current position, so it looked
like a good idea .

Anyway, I recalibrate nose down and will do a test flight tomorrow...

daishi Posted at 2017-1-20 10:09
Thanks for your help guys.
So it looks like nose down is right...

I think you might be wrong there, if your aircraft was rotating in mid air you would receive compass warning, if not you will always run the risk getting a bad compass, half the problems around here are caused by calibration when none is needed.
It is most likely Dji calibrated compass in a suitable place, it doesn't matter if you aircraft came from Timbuktu or Australia a good compass calibration is just that.
As the manual clearly says do not calibrate unless prompted and the first lesson dji will give you is read the manual.
But it's your AC , GOOD LUCK..

hallmark007 Posted at 2017-1-20 15:57
I think you might be wrong there, if your aircraft was rotating in mid air you would receive compass warning, if not you will always run the risk getting a bad compass, half the problems around here are caused by calibration when none is needed.
It is most likely Dji calibrated compass in a suitable place, it doesn't matter if you aircraft came from Timbuktu or Australia a good compass calibration is just that.
As the manual clearly says do not calibrate unless prompted and the first lesson dji will give you is read the manual.

You are right,
a wrong calibration can cause more problems.
But at least in my case the new calibration with the nose down solved my problem of the yaw drift.
I guess I caused it myself by calibrating the compass after the firmware update and holding it on its side.

What made me calibrating it in the first place was that a lot of people in this forum say that one should do it after a firmware update or when flying in a different location.

Anyway, isn´t the calibration to take the difference between magnetic north and true north into account?
How can DJI calibrate it in a special place without knowing where it will be flown?Or is the calibration for a differnent purpose?

daishi Posted at 2017-1-21 10:35
You are right,
a wrong calibration can cause more problems.
But at least in my case the new calibration with the nose down solved my problem of the yaw drift.

You can get compasses that are 'globally balanced' to work everywhere - the Suunto M3 global is one. I'm not 100% sure what compass is in the Mavic , but if there was a need to calibrate your compass on delivery I'm sure dji would have worked that one out.
There is also technology in the Mavic to recognise when calibration need to be done as well as magnetic interference warnings, and when you get a magnetic warning it doesn't mean you need to calibrate your compass as a lot of people think, but rather to move to an area where there is none. Good luck..

hallmark007 Posted at 2017-1-21 10:59
You can get compasses that are 'globally balanced' to work everywhere - the Suunto M3 global is one. I'm not 100% sure what compass is in the Mavic , but if there was a need to calibrate your compass on delivery I'm sure dji would have worked that one out.
There is also technology in the Mavic to recognise when calibration need to be done as well as magnetic interference warnings, and when you get a magnetic warning it doesn't mean you need to calibrate your compass as a lot of people think, but rather to move to an area where there is none. Good luck..

Ok, that makes sense.
Thanks for the explanation.

As everything works as expected now I won´t calibrate again unless the Mavic tells me to.

Harbourside Posted at 2017-1-20 04:12
I did nose down as per the manual, cant say what the app said as it was 30 feet away with the controller.
Just make sure you are well out in the open and away from any interference.
Once done correctly you should not have to do it again, unless you travel thousands of miles away.

thousands? i thought it was 20 miles

So what is the correct orientation? The on-screen instructions show rotate horizontal first, then tip on it's side (not nose down) and rotate. This is the same for both the Mavic and Inspire 2.
It is clearly different from my old Inspire 1 which showed to do the second rotation nose down. Did this change or is it an error on DJI's part. It would be nice to know the official answer.
This, among other head-scratchers, like why is it that now with the Inspire 2 you cannot pan the camera 360 degrees. You must rotate the craft to do a pan or buy a second controller for a second operator.
I know that it is basically the same move, but why remove this obvious feature from a craft that has landing gear that raise up and out of the way of the camera? Maybe I would like to pan my camera instead of the bird. Why is it sometimes the most obvious things that need firmware updates to "fix". Ponder this: If I am filming a stock car race from the center of the track, why would I want to continuously rotate the entire quad when I can simply and smoothly rotate my cam, especially given the fact that the new quick spin feature has been added to avoid the camera's "hard stop".