EKF2 z-gyro bias estimate

Hi there,
I have problem with the EKF2 gyro bias estimate (at least I think so;)).

When I have my drone powered after a few minutes yaw begins to continuously drift - when looking at the gyro data, this make sense, as even for no motion the z-gyro provides a small non-zero value (which is significantly larger than the x/y gyro “zero” values).

I repeated the calibration which helps for the next minutes. However, after some time the problem occurs. I was wondering whether the problem might be due to temperature changes of the sensor, but strong temperature didn’t really affect the gyro offset.
An interesting thing I notice, when I e.g. pitch the drone by 90deg the problem appears on the x-gyro, resulting in a continous drift around the vehicle’s x-axis.
I tried to manually set the gyro bias to the gyro value at stand-stil, the drift vanishes for 1-2 minutes afterwards the problem reoccurs.

For my naive understanding the problem is that the gyro bias is estimate to a wrong value which is an offset to the true sensor bias.

Any ideas and pointers are appreciated!

Thanks
Daniel

What’s the firmware version? What hardware are you using? Could you create a log? You can take a log from boot to shutdown if you set https://dev.px4.io/en/advanced/parameter_reference.html#SDLOG_MODE to 2.

Hi Julian,
we use the pixracer. We already tried various pixracer to make sure that it wasn’t just a single board.
We run the v1.8.2. Firmware on our boards.
I will create a log, but it will likely take until Monday.

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