GPS/Compass Error followed by Vibration Compensation at Low Speed – ArduCopter 4.6.3

General
1

Hello everyone,

I am troubleshooting an issue on a 10-inch FPV quad running ArduCopter 4.6.3 and would appreciate some guidance on the EKF behavior.

Hardware

  • Matek H743-Slim V4

  • Matek M9N-G4-3100 GNSS

The aircraft flies well during hover, but when I apply impulse inputs or perform ascents and descents, I start getting GPS Glitch or Compass Error, EKF disturbances/lane switching, followed by Vibration Compensation ON.

From the logs, the GPS reception appears to be very good during these events, with NSats > 24 and HDOP < 0.6.

To rule out the barometer and compass as potential sources, I am using GSF yaw and have EK3_SRC1_POSZ set to GPS.

The measured vibration levels also remain relatively low, but the GPS/compass and vibration-compensation events continue to occur.

I have two identical systems. One system flies normally without these issues, while the second system consistently shows this behavior.

To rule out a GPS hardware problem, I swapped the GPS modules between the two systems, but the problem remained with the same aircraft.

I have attached the Flight Log.

I would appreciate any suggestions on what could be triggering the EKF disturbance and subsequent vibration compensation, and what parameters or log messages I should focus on to isolate the initial cause.

Thank you.

2

Looks clear that the problem is with the GPS. Those Accuracy Metrics look poor and triggered the events.

GPS Errors
GPS Errors3413×1023 273 KB

3

Hi @dkemxr, Thanks for your input. It turns out the power wires in the second system have been a little too close to the GPS. I repositioned the GPS, did all the wire dressing again making it as far away as I could. I am waiting for weather to clear up to have a go. Lets hope today I am able to do that. I will update as soon as I am able to test.