Hi
what is the solution for compass calibration of the large and heavy vehicles?
It is impossible to rotate the vehicle in 6 direction.
The problem is the whole purpose of compass calibration is to subtract out the magnetic parts of the drone that affect the compass reading. So removing from it the drone is unlikely to accomplish that.
Is it possible to calibrate compasses manually with a calibrated compass?
Why dont you do like this ? Check the video of painless360 (after 18minutues):
Other equipments in drone affect magnetic field of compasses.
In my honest opinion, you don’t have many choices.
I think for now, the best choice would be to mount the compass as far away as possible from wires that could cause a shift in the magnetic field. Then calibrate and try. Never use the internal compass, always external mounted.
There should be an option to calibrate just 1 direction, like in calibration of the accelerometers to just calibrate level.
@mohammad Hey did you happened to find a good solution for this ? Is two sided calibration process a good solution. Your thoughts ?
Regards
I did not finded any Solution, so i calibrate autopilot seprately and then put it in drone.
For this method we must use compass of autopilot because we can not seprate gps/compass from drone.
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if you trust your ability to fly in acro mode, and assuming your magnetometer compensation is good, you can use the data from a flight to generate calibration parameters. Fly in toilet bowls. you don’t need to make a perfect sphere, you just need to generate enough orientation data to make a reliable ellipse fit, ie, your yaw needs to go all the way around, but pitch and roll can stay sort of small. It’s imperfect, but it’s the best you can do with a large craft, UNLESS you can fly inverted.
Large vehicle compass calibration is now available in PX4 and is documented here: Compass Calibration | PX4 Guide (main)
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@bresch awesome! Can you say a bit about how it works?
Which details would you need?
This calibration process leverages external knowledge of vehicle’s orientation and location, and a World Magnetic Model (WMM) to calibrate the hard iron biases.
This means that we simply calculate the sensor offsets by comparing the expected and measured magnetic fields.
Oh it just does hard iron! My bad. I thought it was somehow doing soft iron as well. This makes sense. Cool feature!