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!


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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