I have a RPi3 with Navio2 + an external compass HMC5843, Copter V3.4.3-rc1 with APM Planner 2.
When I rotate my quad by hand on 360 degrees, I see that heading is shifted on ~20° in HUD as well as in a logs. The same problem occurs if I use an internal compasses.
If I turn off compasses then I get normal value.
The same problem: https://community.emlid.com/t/heading-off-by-up-to-40-after-two-spins-on-yaw-axis-with-my-quadcopter/4357/1
log: 14.BIN (736 KB)
What could be a problem?