Unexpected Land in Auto Mission

Last week I had an unexpected RTL in an Auto Mission and today it was a Land Command. There are some EKF errors present at the Land mode but I don’t know what’s causing this. Log in the link if anyone cares to take a look.


Looking at it really quickly it appears you had an EKF_FAILSAFE. Since your FS_EKF_ACTION is set to 1 (Land), that’s what caused it.

It also looks like you had a radio issue where the throttle dropped below the failsafe value.

Thanks for looking Tulsa. The loss of radio/throttle was expected as the mission was beyond radio, and ground station, range. It’s what causing the EKF_FAILSAFE, and subsequent Land, that has me puzzled.

When I was looking, it appeared that the EKF compass threshold was being superseded. Are you flying in an area that might have a lot of interference? Powerlines and the like? Maybe a lot of concrete? Reebar in the concrete can create some compass issues.

I typically don’t have trouble flying in this area with the other quads I have. But I have seen Compass Inconsistent errors in the HUD on occasion on the bench so you are probably right about what caused the EKF fault. Which parameter in the log did you find this “above threshold” fault so I can troubleshoot this going forward? Thanks again for your input.

Compass inconsistent errors are usually triggered when you use both an external and internal compass and have both active. The internal compass will get interference from EMI and make the compasses all wonky. One will be ok and the other will be out of whack.

The error that is most concerning when flying is EKF Compass Variance. That means the EKF expected one thing and got another for a long enough period of time it entered failsafe.

For me, I’ve found it helpful. to use the tlog data to pinpoint where in the flights my vehicles are having the worst problems with EKF compass variances. It easiest if you’re using firmwre 3.3.x and above (and you appear to be using .3.4 rc1).