System-level calibration for the star sensor installation error in the stellar-inertial navigation system on a swaying base

The star sensor installation error has a great influence on the attitude accuracy of the stellar-inertial navigation system and should be precisely calibrated. However, it is difficult to realize the installation error without a proper reference on a swaying base, which becomes a limitation for operation accuracy and reaction ability improvement. In this paper, a star sensor installation error calibration method on a swaying base is proposed. The measurement equation is established using accelerometer information, gravity and direct star vector observations in the inertial frame. The state equation is deduced according to the navigation error model. The installation error can be calibrated in the inertial frame instead of the zero-velocity information with respect to the Earth. The simulations and experimental results indicate that the proposed method performs much better than the traditional method on a swaying base. The calibration accuracy can be within 1 arc-s in simulation, and the stability is approximately 5 arc-s in the experiment. High accuracy can be achieved without precise external devices and artificial references. The proposed method is very suitable for mooring ships and for readiness on duty vehicles. The on-line accuracy and rapid-response ability can be significantly improved.