The BNO055 contains internal sensors to measure the absolute orientation. It does not require production line calibration. Calibration happens at run time with the natural movement of the device.
When installing in vehicles however, the steel structure of the car may interfere with the magnetic sensor of the BNO055 making heading value less accurate. It is best to mount it far away from ferromagnetic meterials, such as steel in screws and cases, and cobalt in lithium-ion batteries.
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