Abstract: MEMS inertial sensors benefit the lowcost and miniaturization of strapdown inertial navigation system， but their errors are large. To improve the navigation performance， a systematic error autocompensation method—rotation modulation(RM)was introduced. The RM effects on restraining constant biases and improving navigation accuracy were elaborated. The rotation modulation schemes including the number of rotating axis， rotation direction， rotation continuity and rotation speed were compared. Based on the error characteristics of MEMS sensor， an appropriate rotation scheme was determined for that and a prototype was selfdeveloped. Static and land vehicle experiments showed that RM can greatly improve the navigation performance by constraining the constant biases of MEMS sensors. The attitude accuracy is 5 times better and velocity/position accuracy is nearly 10 times better in 200s.

Key words: rotation modulation, MEMS sensors, SINS, IMU, error autocompensation