Hi,
Thanks for your inquiry.
Regarding NDOF sensor fusion and magnetometer calibration please refer to online article at https://www.edn.com/sensor-data-fusion-enhancing-gaming-navigation-and-vr-experiences/.
BNO055 NDOF sensor fusion has 2 bits magnetometer calibration status in register 0x35. 3 means the mag is fully calibrated and the heading output of BNO055 has good accuracy. 0 means that the mag is not calibrated and the heading output has large error. 1 and 2 mean the mag is being calibrated or partly calibrated. Performing figure-8 motions in 3D space can calibrate the mag automatically.
So when BNO055 is operating at indoor magnetic inference situation, you can always monitor the mag calibration status value. When the value is 3, you can trust the heading. When the value is 0, you need to perform mag calibration.
Thanks.
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