Since the IMU and the Barometer are the only things keeping the Mavic airborne when GPS signals and visioning position is unavailible which can happen for a number of reasons I wanted to ensure mine was as dead nuts right as possible. I've watched several videos on IMU calibration of the Mavic and noticed most do not put an emphasis on performing the calibration on a dead level surface and many show the calibration being done with the props in place.  The instructions say to perform the calibration on a level surface but I suspect many folks assume their floor, deck, or table are level which is often not the case.  Also in the intructions it says to remove the props, yet the pictures that appear on the screen show the props installed and I think this confuses people. Anyway, I did an IMU calibration today and thought I'd post up the process I used and the results.
First - I made sure my work surface was actually level by checking it with a decent level in both directions.



Here is why IMO it's important to take the props off before starting the calibration. Note that with the props on the Mavic does not sit exactly as intended during the calibrtion process:

This...


Opposed to this...



Level surface, props off, and ready to begin IMU calibration


Make sure to not disturb the aircraft while the calibration is running until instructed to rotate the craft into each position shown on the screen of the device you have connected to the RC.








Once the process is completed flip the mavic back upright and restart it and check your IMU readings.




The real test though was to see how it would fly in ATTI mode with no GPS signal and all visioning positioning turned off so I headed for the basement where all GPS signals are blocked.



I didn't set up a video camera for this test flight and wasn't going to trust my exensive quad in the air with my hands not on the remote to take another picture with it in close quarters and blinded. With all sensors off except for the IMU and barameter it flew absolutley as well as could be expected with no tendancy to drift in any particular direction and was very controllable considering it was flying blind. Caution is strongly advised if you try flying it in this mode in close quarters with this expensive piece of tech. With no sensors to assist other than the barameter and IMU it will bahave very differently than you may be used to. You will need to make slight corrections for altitude and drift on a nearly constant basis. Get heavy handed or panic and you will toss into into a wall, ceiling or floor.

Anyway, that's it. No fancy polished pictures or video but hopefully this will help someone who may have blindly followed the steps of a nice looking video that may have had bad instructions.

I'd welcome any comments/opinions from folks about the process as I outlined it and if you have found the IMU calibration not all that important. For me, I know I feel more confident knowing that my Mavic will fly well with only a minimum of sensors active to assist when things go south.

Awesome post with the level and tile. Mine tends to drift backwards though while atti with a level calibration. Gyros all read .002 - .005

Maybe I should take it out in the garage and do it where there's no central heat. Supposed to do it cold.

Great info.. Thanks for sharing..

Irish Posted at 2017-1-31 10:18
Great info.. Thanks for sharing..

Great post.

I would just add put the AC out in the cold for half hour and then follow the above instructions with NO props.

nice write up...

Since the IMU and the Barometer are the only things keeping the Mavic airborne when GPS signals and visioning position is unavailible

While you did a good job calibrating your IMU, your information that IMU and barometer are the only things keeping your aircraft in the air is quite wrong.
If you loose gps and VPS the one thing that will keep your AC from dropping out of the sky is radio control and a good pilot,

IMU has nothing to do with keeping your AC in the air,
The IMU controls the stability of your AC by monitoring the AC tilt relative to its desired tilt, the IMU can adjust the speed of the motor to return the AC back to where it should be. It also does a whole lot more , but it doesn't keep your aircraft in the air.

Barometer are used to measure the rate of change of pressure as height increase and so offers height information.

And although you have completed your calibration successfully , I'd does say in the manual NOT to calibrate your compass or IMU unless prompted, I do imagine this is because there is a good chance if everyone was doing this there is a good chance that many would get it wrong and this may have a very detrimental effect on a lot of people's Aircraft.

However having said all that your demo of how to preform IMU was a good one.. good luck..

@ hallmark007 - Great point about it being the pilot and the controls keeping the unit airborne!   I should have stated the IMU being properly calibrated makes it easier for the pilot to keep the craft under control.

I agree that the chances of screwing up the calibration is likely the reason why owners are instructed to not perform a calibration unless prompted.  Like a compass calibration, getting it wrong could have a much larger detrimental effect than it being slightly out of calibration.  I don't know how far out of calibration the firmware allows the IMU to get before prompting for it to be recalibrated but I suspect it allows for a fair amount of variance.  Regardless, having seen many videos that appeared to skip a couple of relevant points of the process I thought I'd throw how I had done it out there. I appreciate the feedback.  

@Dronist - Good point about having the IMU cool when calibrating. Dang it. It's so easy to miss mentioning important points!  Mine had been in the car overnight so it was pretty cool when I started but I didn't mention it.

great information i always assumed my floor was level. i may need to check even tho i have no current issues but i may recalibrate anyway to make sure its perfect

no more photo ? i cant not see :-(

Kilroy Posted at 2017-2-1 13:25
no more photo ? i cant not see :-(

Seems ok now? I did link to the photos from my photobucket account and some places block photobucket. Should have thought about that and maybe loaded them directly to this site.

Yes Perfect.
Thank you very much for sharing

I have always wondered about "level". If the mavic itself needs to be true level during the whole calibration. What about when you're directed to stand the mav on it's tail end with the front pointing up? That's definitely not level, it's angled in quite a bit because of the slant of the legs. Is that something to worry about?

This is really great information. Very well done too. I did not know about the cold aspect. When I first got my MP I obviously did the IMU calibration, I even checked for level on my tile floor. I believe I have only recalibrated it once since. However, I often check the IMU to see if has drifted. I would not accept anything more than .005 and if one is off I would recalibrate.
Thanks very much for all the work. It fills a lot of squares that the manual doesn't.