Sudden position drift with EKF2 and motion capture causing crash


The quadcopter is using motion capture. Position data is forwarded from the ground with a wifi link to a companion computer. The data looks good from the motion capture software, and in the log (Visual odometry position)

However, the local Z position estimate diverges quickly at 2:20, causing the crash:

The vertical position check bit is triggered at 2:20, so the estimator detects the divergence.

It could be an issue with the wifi. If there is a sudden lag spike, I think it would be undetected in the log files, and the packet would arrive late, but the data would still look correct on the log file as there is a timestamp.

Is there any other clue I could get from the log file?
Any idea of how to troubleshoot this?

Here is the log file of the issue:

@charles-blouin You have ALOT of vibration in your airframe. This might make the EKF to diverge

Thanks, it makes sense. I will check this and update.