A Novel Sun Direction/Solar Disk Velocity Difference Integrated Navigation Method Against Installation Error of Spectrometer Array

Solar disk velocity difference is a novel celestial navigation measurement, which can be obtained by four spectrometers installed on the four corners of the quadrangular pyramid. However, the characteristic of the spacecraft's high dynamic results in the spectrometer installation error. Spectrometer installation error has an obvious influence on navigation accuracy. To solve this problem, an augmented state Sun direction/solar disk velocity difference integrated navigation is proposed. After analyzing the influence of spectrometer installation error on the solar disk velocity difference measurement, the spectrometer installation error is augmented into the state vector. The state model and measurement model of the augmented state Sun direction/solar disk velocity difference integrated navigation considering spectrometer installation error are established. Unscented Kalman filter (UKF) is used to estimate and correct spectrometer installation error. Simulation results show that the proposed method greatly suppresses the effect of spectrometer installation error on navigation accuracy. Furthermore, the effects of the Sun sensor accuracy, the sample time, the number of spectrometers, and the spectrometer installation error value on the navigation performance are analyzed.