Navigation accuracy of SINS steps down gradually with the passage of time, and the gyro drift and accelerometer bias are the primary elements that result in the decline of navigation accuracy. With the emergence of rotating modulation technique, a four-position drift measurement of SINS based on single-axis rotation in static or mooring conditions is proposed. Gyrocompass alignment is conducted as an auxiliary tool and the misalignment angles are related to gyro drift as well as accelerometer bias after alignment, and then the conversion relationship between the attitude error and misalignment angles is derived. Attitude error can be obtained with the transposition of rotating mechanism and the results of gyrocompass alignment. The sensor drift are calculated with the equations which established by the relationships between misalignment angles and inertial sensor drift. Finally, both the simulation and turntable experiments validate its effectiveness. The results show that the gyro drift and accelerometer bias can be accurately calculated, and the accuracy is better than 90%. Position error can be reduced by nearly 50% after the inertial sensor bias were compensated.
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