Robust in-flight alignment approach for inertial navigation system with GPS aiding

Accuracy of inertial navigation systems (INSs) depends on how to eliminate or attenuate the influences of the external disturbances, internal noises, and parametric uncertainties. In this paper, a robust in-flight alignment approach is proposed for a class of INSs with multiple disturbances. Based on modeling and noise analysis, the drifts, unmodeled dynamics, parametric uncertainties, external disturbances are formulated into different types of disturbances. In the proposed approach, the drift filter is designed to estimate the inertial sensor drift for compensating. The robust H_∞ filtering is designed to attenuate norm bounded uncertain disturbances. Finally, simulations for in-flight alignment of an integrated INS/GPS system are given to show the efficiency of the proposed approach.