Hi there, sorry to be absent for so long on this issue.
We’re preparing to release Copter-4.0.4-rc1 for beta testing this week and I’d like to ensure we get the right fix (if necessary) included.
The basic check is that the two EKF cores and DCM are all reporting the same attitude. I think we have a couple of different failures reported above:
- “EKF2 Yaw inconsistent by XX deg” means that the two EKF cores are reporting different headings which is quite bad and we should try and resolve this. It seems like from the analysis above that some IMUs are suffering from high z-axis gyro drift. I would have though that performing a gyro calibration would resolve this.
- “DCM Yaw inconsistent by XX deg” means the DCM doesn’t agree with the EKF. This is probably a false-positive and I’m planning to disable the check of DCM because we don’t actually use it in copter. It runs in the background but the flight code never uses it for attitude control or anything except reporting.
So if you’re seeing these types of errors:
- if it starts with “DCM Yaw” please post a log and I’ll have a look to confirm that the EKF is OK and we can disable the DCM check in 4.0.4
- if it starts with “EKF Yaw” then please try triggering a gyro recalibration and see if that fixes it. If not then please post a log and I’ll have a peek.
- I don’t think it’s a good idea to switch to the EKF3 to try and get around this problem. The EKF3 seems safe but we know there are some small issues. By the way, we plan to make EKF3 the default for Copter-4.1.0.
@Bobmarr kindly provided logs above. I’ve had a look and in the 11.BIN log it looks like DCM is off, in the 12.BIN log it appears the 2nd EKF lane is off. I’ll discuss this with Tridge and others.
Thanks very much for the log and sorry for the delay on this!