EKF Velocity and POS error > EKF Lane switch > Scary in-flight AHRS error

Vova_Reznik_RangeVid · November 3, 2021, 3:55pm

This was a scary moment in flight-
Seems the GPS glitched and caused the EKF to go a bit crazy.

Hope someone can analyze the log with more insight.

Plane 4.1.1 Holybro Mini Pixhawk4. Matek M8Q
Tlog and .bin:

https://drive.google.com/file/d/1F_0kjmfY_7NbfeiHomI9o-asQBO4gYRM/view?usp=sharing, https://drive.google.com/file/d/1yQ2eyEh-mn96Anzz4kMpDgFaO2nRimj7/view?usp=sharing

Vova_Reznik_RangeVid · November 3, 2021, 4:03pm

vbnhu · November 3, 2021, 9:53pm

Looks similar to: EKF3 Lane Switch - almost a FRIDAY FAIL
and EKF3 switching to DCM and back - #2 by vbnhu
@priseborough says: "The lane selection logic got suckered into a switch to the second IMU EKF by a GPS glitch at 04:54:50. Unfortunately IMU2 had developed a large Y gyro offset before takeoff and was in intermittent bad health which allowed the switch.

This is another example where the user should have been warned by the GCS if the backup EKF is unhealthy."

Vova_Reznik_RangeVid · November 4, 2021, 1:04pm

I think the safest option for me will be to disable EKF completely.

tridge · November 8, 2021, 9:49pm

Your GPS did indeed glitch:

it was particularly bad in height:

your GPS is claiming you climbed 200 meters in 20 seconds, whereas the baro shows you didn’t climb at all.
The EKF correctly fixed the error and allowed you to keep flying.

I don’t understand why you would do that. The EKF corrected the GPS glitch. If you disable it and get a bad GPS glitch then you would be much worse off.

Vova_Reznik_RangeVid · November 11, 2021, 5:55pm

Thank you. I will change GPS with larger antenna and enable EKF3 and test again.