Bosch BNO055 disappointments

I have started testing EFIS 19264 flying at zero ft AGL 🙂

In other words I have set it up in my car and compare magnetic compass to GPS magnetic heading and altitude to GPS altitude.

Good news is the altimeter is working wonderfully. With QNH set correctly the altitude was always within +/- 25ft of GPS altitude.

Its accelerometer is perfect.

Its gyro is OK (occasionally displays a small false roll, but recovers within a few seconds)

The magnetometer of the BNO055 is the centre of my disappointment.

The main problem is it drifts away over time by as much as 20 degrees. It doesnt hold calibration in a moving car. The calibration level goes from 3 down to 1 within minutes of driving. Resetting the unit with the stored calibration data only helps for a minute.

I think the problem is that the internal software is constantly re-calibrating the magnetometer. There is no way to disable the re-calibration in the NDOF operation mode.

The problem with heading drift could be hiding in the magnetic field distortion created by the car’s body and its electric circuits. The degradation of the calibration status is anyone’s guess.

I’ll keep testing the system in the car some more. Maybe the issue has environmental roots.

I’ll also try to contact Bosch support. Will see what they have to say about it.

If this is a limitation of BNO055 chip, then I need to look for some other alternatives.

If you use BNO055 for your systems and found the solution for compass drift, please let me know.