Hi everyone,
I’m working with a Cube Orange+ (ArduCopter 4.5.7) on a hexa-frame. We’ve observed a strange and concerning behavior during GNSS spoofing or jamming tests.
While the drone is stationary on the ground (not armed), the IMU reports motion: sometimes indicating that the drone is rotating, tilting, or even slightly changing altitude – even though it is not physically moving at all. Ground speed is about 60m/s. This includes noticeable changes in accelerometer and gyroscope values, as if the drone were flying. At the same time, GPS positions differ significantly (even by millions of meters) and the EKF switches states or resets frequently.
Interestingly, this behavior happens only on one of our test drones. An almost identical drone placed next to it during the same tests behaves correctly – IMU remains stable, and no false motion is reported.
I checked paramlist, logs and it seems like IMU sensor is OK. Message shows IMU is using GPS. But why it does onlly on one drone and doesn’t on the almost same one? It also could be some magnetic field from USB ports on Raspberry, but seems strange due to normal work on another drone.
Must say that we’ve been working with this drones for a year, and no such problem was noticed even with strongest spoofing areas. What could it be? Thank you!