Problem with GPS and AHRS difference and a hard landing of the drone


we ran into a little problem with our drone, hope you guys can help me out with finding the problem.

The problem started with the error message “GPS and AHRS difference by 10m” sometimes more. So far I never had this message with any drone. So we disconnected the battery, connected it again, no error message and the copter could be started. The flight was okay, no real problems. After changing the battery, the same message comes, we did the same thing, short flight, everything was okay.

The next day, same location, again the message, but this time the flight was very instable with holding the height. We landed, restarted the drone and did another flight, first it seemed to be okay, but shortly the drone goes down, we tried to give more throttle, without any results and the drone did hard landing. So far, only the landing gear is damaged.

You can check the logfile and here the part, where the crash from the last flight happened.


So far, I didn´t find the real reason for this, hope you can find more in the logfiles than I did.

best regards

Hi do you find any source of this problem! I start to see this message today after using 2 GPSs

What version are you using?
Please update to 4.4.2 the error messages have improved and are more descriptive

I am on 4.3.7 i will try to observe more and get the log to see.

The solution might be to wait longer before arming, to make sure the solutions have time to converge. Post a .bin log file with LOG_DISARMED = 1

We made 8 flights today. the last flight it gets GPS glitch or Compass error.
something to do with compass and GPS. but this time EKF lane switch and land badly.
The GPS seem to work okay. but why it went to glitch?

Crash log

GNSS receivers glitch when they have interference.
Have you done EMC tests with it?

Have you calibrated the compass with MagFit using MAVExplorer?
Compass drifts when the high current wires are near the compass.

I did not do EMC tests. Actually I don’t even know what it is. :wink:
it is happening 2 times at the same place that GPS glitch or Compass error message promp and then crash.

Have you calibrated the compass with MagFit using MAVExplorer?
I normally do compass dance with QGC.

EMC Electromagnetic compatibility tests

Instead of compass dance you need to do a compass flight followed by magfit using mavexplorer