BNO055 Magnetometer and External Fields

[jspear16]

We have been playing around with some functionality of the BNO055, and decided to test out it's heading accuracy given a powerful external field (such as placing a permanent magnent) nearby, and to our surprise there was no change in the readings. We see that there is a functionality where it mitgates magnetic field distortion once it is calibrated, but it is still confuses us that, if something like a magnet is slowly brought close to the sensor from a significant distance, shouldn't there be some form of disturbance being detected? We like this functionality, but are skeptical of it's reliability. So, if I am completely incorrect with my assumptions, please correct me, and any explanation that can be given on this feature would be greatly appreciated.

Thanks!

[BSTRobin]

Hello jspear16,

There was sensor fusion software runs the calibration algorithm in the background to remove the offsets(acc, gyro, mag) inside BNO055.

[jspear16]

Is this a proprietary software to Bosch? Is ther any other general information that you can share with me in regards to how the system makes these offsets? If not, that's understandable, but I would like to ask just in case.

Thanks.

[BSTRobin]

Hello jspear16,

The fusion algorithm runs inside the sensor and is not officially released. You can configure how to use it through the register instructions in the data sheet.

[jspear16]

Ok, just to put a cap on this thread, it can be said that the driving algorithm used in the BNO055 is robust enough to tell the difference between a magnet being brought close to the device, and an actual change in position because of the combination of data from all three sensors?

I am assuming this is correct, but I just want to end in clarity.