|Strapdown Inertial Navigation System (SINS)/Celestial Navigation System (CNS) integrated navigation system, owing to good autonomy and high accuracy and high reliability, is an important development trend of ballistic missile integrated navigation. However, large velocity, position and attitude errors can be caused by initial misalignments, gyro drifts and accelerometer bias during the course of the SINS/CNS integrated navigation because of environmental disturbance, model nonlinearity and uncertainty. The integrated system can estimate online attitude errors and calibrate gyro drifts with CNS after the ballistic missile flies out the atmosphere, and then can compensate the velocity and position errors caused by initial misalignments and gyro drifts, but no estimating the accelerometer bias and compensating its velocity and position errors. To this shortage, an online compensation method based on genetic programming (GP) and Genetic Algorithms (GA) for movement error of SINS/CNS integrated navigation is presented. This method adopts a compensating model based on the system’s state transition matrix built and optimized by GP and GA to deal with the environmental disturbance and model uncertainty, and use the Unscented Kalman Filter (UKF) to solve the nonlinearity of system model and the observation model. The method will be valid and can be used to effectively compensate the velocity and position errors caused by accelerometer bias of SINS/CNS integrated navigation system.
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