My application is a 2-axis pitch-roll gimbal, to watch for whale blow from a moving boat. The camera must stare continuously at the horizon, unattended for weeks and months.

I have an Extended Long board, encoder firmware and GUI version 2.7b0, and I have tried tuning with a Basecam I2C IMU and a Basecam CAN IMU and in both cases I have the following problem:

When I first power up the gimbal it points level in pitch and roll as expected. But after a few minutes, pitch and roll have drifted, extremely slowly, a few degrees. They continue to drift over many minutes until these axes hit their mechanical stops. I'm trying to eliminate this drift.

I believe it should be possible for the Basecam gimbal to compensate for this drift by using the accelerometers ( and a very low-pass filter). I don't understand why the controller doesn't do this by default.

The only setting that seems to make it do what I want is Hardware tab -> IMU Sensors Settings -> Gyro-to-accelerometer trust. If this is zero (default), the gimbal is stable and works well, but drifts over many minutes. If I set it to 1, it is stable and doesn't drift, but linear surge/sway accelerations cause significant and unnecessary excursions in pitch/roll.

Is there a setting that I am missing that will produce the expected long-term drift compensation without coupling the platform acceleration to the gimbal rotation axes?

Thanks for your help!