IMU calibration strategy

[AndrewS]

Hello. To avoid negative interference effects, one strategy I've heard is to do your IMU and compass calibration in an open area and away from metal objects. Assuming this is best practice, do I need to keep the unit on after calibration in order to "store" the calibration in the unit? Example: my subject flight area is located in an urbanized area with lots of metal around. One approach: I calibrate in a park some distance away from my subject area, then once completed I drive to subject area for the flight. In that example, can I turn the unit off or do I need to keep it on after calibration? Thank you!

 

[MNT DRONE SOLUTIONS]

If my Flight location is more than a 1/4 mi. away then I would recalibrate the compass. As long as you do an IMU on a flat level surface, you should not have to do one again unless you are having major flight issues and as long as you are 15 ft or more away from any obscuring objects you should be good do do a compass cal.
Just my thoughts. Safe Flying, Blue Skies!

 

[AndrewS]

Ok, got it. So, if I go to a nearby park to calibrate (say, to avoid heavy metal objects at the subject flight location), do I need to keep the drone on to retain the new setting changes until I reach my subject flight location? And your comment about "not having to do it [IMU calibration] again unless have major flight issues" confused be a bit because the IMU calibration on the EVO Pro 2, per the manual, occurs every time you power it on. ["Automatic IMU calibration is performed when the aircraft is powered on."] Thanks for your words of wisdom!

 

[MNT DRONE SOLUTIONS]

No, once you do your calibrations and power off the Drone it will retain the calibration settings. If you fly in the same area on a regular basis you will not have to recalibrate again, but if you change locations and as I said it is more than a quarter mile away I would do a compass calibration only again. You should only have to do an IMU once after each update.

 

[AndrewS]

Ok, thanks much. Incidentally, I just watched this Autel Robotics Youtube (Date: Nov 13, 2020) which describes the new IMU Calibration option which has been added to the Autel App. So we do now have the option to do IMU calibrations at any time. Strangely, he performs the calibration indoors. I would have thought the metals in a home would throw it off.

AUTEL EVO II FIRMWARE UPDATE: Constantly updated ( new V1 STABLE fw 2.7.35) - 28/02/2022 - (NEW V2 STABLE fw 2.3.8 - 19/04/2022)

Ok after testing with 2.5.12 with Android 1.1.7.10 here are my results and the error isn't always fixed. First Gimbal Calibration: Default UV lens = successful Freewell ND (non CPL) = successful Freewell ND/CPL = Fails Startup Gimbal tests. Start Evo II first let it setup and turn on RC and...

autelpilots.com

 

[Rubik3x]

I'm not an expert, but I think IMU calibration is only for the accelerometers. These respond to gravity, not the magnetic north pole. Therefore, since gravity is virtually the same everywhere, you only need to do the IMU calibration once, starting on a level surface, indoors or outdoors (or after an upgrade or accident).

The compass calibration should be done away from anything that could distort the earth's magnetic field, such as massive metal objects, pipes, powered electrical wires, etc. I would not worry about recalibrating the compass unless you want to fly many miles (100+) east or west from the previous compass calibration location.