Information-reusing alignment technology for rotating inertial navigation system

Abstract

This paper proposes a real-time information-reusing alignment strategy for rotating inertial navigation system (INS), which is devoted to improving alignment performance in a limited time by making full use of all sensor data. In the forward coarse alignment stage, all sensor data was recorded for subsequent fine alignment while the rough attitude was determined, and the well-designed data extraction strategy significantly reduced the memory space and the computation load without losing solution accuracy. In the fine alignment stage, the stored data was used for backtracking navigation update and Kalman filtering in the local level geographic frame rather than the inertial frame, simplifying the fine alignment algorithm. The lever arm between the center of the inertial measurement unit (IMU) and the rotating center of the turntable was automatically estimated by the fine alignment Kalman filter, which helped to suppress motion interference and improve alignment performance. Finally, the simulation tests and the practical experiments justified the proposed information-reusing alignment method.