Initial Alignment Method for Rotating Strapdown Inertial Navigation System Based on Fuzzy Adaptive Kalman Filter

The rotating strapdown inertial navigation system (RSINS) has been studied on the basis of traditional system structure. The gyroscopes and accelerometers are installed on the rotating base, thus their non-stochastic errors could be eliminated by the integral calculation in strapdown navigation algorithm. Considering the structural characteristics of the RSINS, a novel initial alignment method based on fuzzy adaptive Kalman filter algorithm is proposed, which can rapidly estimate the platform misalignment errors. In this paper, the error mathematical model of the navigation system is established, according to which the state equations and observation equations are derived. The verifications based on fuzzy adaptive Kalman filter are given via digital simulation. Finally, based on a certain type of IMU with fiber optic gyroscopes (FOGs) and Micro-Electro-Mechanical System (MEMS) accelerometers, the algorithm performance of the practical navigation system is further verified through a rotating experiment on a high-precision rotating platform. The results show that, the proposed alignment method has comparatively high alignment performance for low and medium precision FOG RSINS, thus having certain engineering application value in aviation-related field.