EKF or Inertial Nav failure

Hello to the forum. I’ve just set up my first Pixhawk in a small hexacopter and all seems to be well except I keep getting a flashing red/yellow light with a rising tone whenever I start chucking the copter around with any enthusiasm. Apparently this error is “EKF or Inertial Nav failure” but I can’t find any info on what this actually means. Apart from the warning signal, there’s no noticable problem in the way the copter handles.

Should I be concerened about this and if so what should I do?


Thanks for the reply and here’s the extra info.
I have a Pixhawk running 3.2.1 with a 3DR GPS/compass unit. It is fitted in a small custom built “spider” style hexacopter similar to a Blackout Hex, controlled by a Taranis and X8R radio. The alarm sounds when I fly in stablize mode and only when I start throwing it about. I can’t feel any problem in the way it responds, it’s just an alarm. I have flown in loiter mode, but it is not sufficiently responsive to throw about enough to cause the alarm. The position hold in loiter is poor with a lot of toilet bowling which I think is maybe because I have the compass unit too close to the ESCs and their wiring.

There’s a log attached which seems to show some compass error.