Automatic realtime offset calibration of gyroscopes

This paper reports on realtime offset calibration of a three-axis gyroscope, especially, offset calibration of a gyroscope exclusively based on the redundant information of one three-axis accelerometer. The self calibration is based on the knowledge that the output of any gyroscope equals zero if the inertial measurement unit is in a static position. For this purpose, a sophisticated movement recognition has been developed using unaligned acceleration signals containing sensitivity and offset errors. The proposed movement recognition identifies not exclusively human caused activities, which is state of the art, but rather extends the sensibility to small, constant yaw rates which are close to the ground noise floor of the static gyroscope. These very small, constant yaw rates are in the range of possible offsets and not identified through previously presented movement recognitions. The effectiveness of the proposed movement recognition overcomes this drawback and enables the complete rejection of the environmental dependent offset of any gyroscope. The performance of the auto calibration algorithm has been evaluated by means of simulations, human movement patterns and movement patterns generated through a turn table.