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Gyroscope: it gets self-calibrated quickly, and usually doesn’t need to move the sensor around to finish the calibration
Magnetometer: the most cumbersome calibration. For a magnetometer to sense the Earth’s magnetic field correctly, it needs to remove the magnetic field effect caused by the magnetic materials from the aircraft body and the electronics on board. The calibration requires the sensor to be mounted on the aircraft and rotates the aircraft to different angles until the sensor figures out the correction parameters.
Further Reading
References:
https://www.vectornav.com/resources/inertial-navigation-primer
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