EKF compass free operation failsafe

ArduCopter Copter 4.5
1

I’m flying a 10" (flat) carbon frame quadcopter without compass due to high variance following Compass-less Operation — Copter documentation.

I’m getting a lot of EKF issues claiming “GPS glitch or compass error”, “EKF variance” and a land failsafe towards the end of the flight.

In logs, I can see a lot of innovation in position and yaw, the conditions were slightly windy, maybe 3m/s or so.

I’m not familiar with EKF3 operation so some tips would be nice on how to approach the issue. GPS signal should be good, sattelite count is generally above 20.
I’ve also noticed in flight that at least on OSD the horizon from ardupilot is tiltled relative to the real horizon. Also surprised that EKF is not doing any windspeed estimation, is this intentional?

Vibrations are in 99% of the flight below 20(VIBE values in log), not sure why the z vibration excursion occurs in the middle but errors don’t seem related to that.

google drive link:

Any ideas on how to debug the issue?

2

There are several messages about vibration failsafes (Vibration Compensation On).

I’m not certain but I’m going to guess that using the GSF will make the EKF more sensitive to vibration issues. You might want to chase down the vibrations a bit more than you might need to on a quad with a compass.

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