Gten says that the V3 doesn’t need calibrating..
That might be true, but calibrating the compass is a good thing to do, and is very important as well in case of a RTL.
If you use RTL and the compass orientation is not good you might get a fly away!
Also when you have a lot of toiletbowling you might want to calibrate the compass.
Some people say that hovering in ALTHOLD and turning 2x 360 left and 2x 360 right is enough to calibrate.
I have never noticed any difference, and I don’t think that will work to be honest.
If you want to calibrate the V3 you do need missionplanner, and you can download that in this post
You can only do the calibration if you have done the USB Mod
Once you have prepared everything it is important to watch this video from the marker I have set.
That shows you exactly how to calibrate your compass, and that will stop toiletbowling and any other compass related issues!
Be sure you have set the rotation to ROLL_270!! that is VERY important! otherwise the calibration will fail!
Make sure you are at least 1m away from any metal objects before you start calibrating.