Compass problems, why the two or perhaps more and possibly mutually exclusive symptoms?

Yorkshire_Pud · Jul 18, 2022

That I have seen there are two symptoms.
1) Take off is allowed and then the drone flies seemingly out of control and some times in an arc.
2) A warning saying that "compass calibration is required" etc. is issued and the drone will not start motors.

I am not asking for the solutions, I am asking why differing symptoms?

akdrone · Jul 19, 2022

what drone are you talking about? I've never seen either symptom. I fly a Mini 3, Mavic 3 and FPV. Might you be trying to fly from a place or area with magnetic interference?

Yorkshire_Pud · Jul 19, 2022

Any of them. There is a Mavic 3 flyaway thread running at the moment which seems to be due to 1) and that is actually what prompted this question. I quite frequently get compass needs calibrating messages with a Mavic Mini.

Meta4 · Jul 24, 2022

Yorkshire_Pud said:
That I have seen there are two symptoms.
1) Take off is allowed and then the drone flies seemingly out of control and some times in an arc.
2) A warning saying that "compass calibration is required" etc. is issued and the drone will not start motors.
... I am asking why differing symptoms?

There are two important features of magnetic fields:

Strength of the field

Direction of the field

The magnetic field that the compass works mostly is the earth's magnetic field, which is fairly weak.
When the compass detects a magnetic field that is stronger than the earth's magnetic field, it's programmed to warn you.

When the compass is close to a magnetic field of similar (or weaker) strength to the earth's, if it is has a different direction to the earth's field, it can deflect the compass but you won't get any warning because the compass has no way to tell that it's not the earth's magnetic field.