@sar104:
- The link attached to " It works," is dead. Do you have another URL to this webpage?
- I want to compliment you for your clear and accurate article
"A short explanation of compass function, calibration and errors". And also for your experiment with a disturbing magnetic field: "
Compass error demonstration". Both very illuminating!
For me two lessons stand out:
- Check the heading of the direction indicator as soon as the aircraft reaches an altitude of ca. 10 metres.
- Never calibrate the compass if you are not absolutely sure there are no magnetic disturbances in the vicinity of the aircraft.
I find it strange that DJI orders to calibrate the compass as soon as its measurements are 'out of bounds', because there is no way the system can know whether this is caused by environmental causes or by causes connected to the aircraft. In the former case it is even dangerous to recalibrate the compass because compensations will be made to counteract magnetic deviations which will not be present anymore after takeoff.
Electric currents cause magnetic fields. Once I got a compass calibration message in a meadow about 2 metres away from an electric fence (for cattle, only a few wires). On YouTube I have seen video's where drones are used to inspect high tension electrical transport cables, and the masts carrying them, in close proximity. I know these lines cause deviations to hand-held compasses on the ground, so I wonder how those inspections can be done.