Research on Error Online Calibration Method of Inertial/Stellar Refraction Integrated Navigation System

Inertial/stellar refraction integrated navigation system can use the observation information of the refraction star sensor to correct the output of the inertial navigation system (INS), thereby effectively improving the positioning performance of the integrated navigation system. However, in practical applications, the errors of navigation system such as inertial navigation misalignment angle and star sensor installation error will affect the overall performance of the integrated navigation system to some extent, so it needs to be calibrated online. Since the carrier cannot achieve continuous observation of the refracted starlight, the system observability is weak. Therefore, a new online error calibration strategy is proposed, which is to construct observations by using the position information of the INS and the attitude and star spots information of the star sensor, and establish the relationship equations between the observations, the misalignment angle of the inertial navigation and installation error of star sensor. After linearization and decoupling, the inertial navigation misalignment angle and star sensor installation error are estimated by the least square method. Monte Carlo target practice simulation results show that, compared with the traditional filtering estimation method, the system error online calibration method proposed in this paper can more effectively estimate the inertial navigation misalignment angle and star sensor installation error, and improve the positioning and speed accuracy of the inertial/stellar refraction integrated navigation system.