A high accuracy multiplex two-position alignment method based on SINS with the aid of star sensor

In order to achieve high precision of initial alignment and inertial sensor calibration, this paper proposes a high accuracy multiplex two-position alignment method based on SINS (Strapdown Inertial Navigation System) with the aid of star sensor. Firstly, the Mars rover's approximate initial position is determined by the lander's landing position, and its initial attitude is obtained with the time and the output of star sensor. Based on that, a two-position alignment method aided by star sensor's precise attitude information is used to improve accuracy of initial alignment and inertial sensor calibration. It can take full advantages of both inertial navigation and celestial navigation. Finally, we deduce the relationships between estimation errors of accelerometer bias, estimation errors of misalignment angles and position errors. The rover's higher accuracy initial alignment is achieved by using the deduced relationships and the estimates of accelerometer bias to correct the rover's initial position and attitude. The simulation results demonstrate that the presented method can meet the high accuracy requirements of the rover's initial alignment and inertial sensor calibration.