Stochastic Integration H∞ Filter for Rapid Transfer Alignment of INS

The performance of an inertial navigation system (INS) operated on a moving base greatly depends on the accuracy of rapid transfer alignment (RTA). However, in practice, the coexistence of large initial attitude errors and uncertain observation noise statistics poses a great challenge for the estimation accuracy of misalignment angles. This study aims to develop a novel robust nonlinear filter, namely the stochastic integration H filter (SIH F) for improving both the accuracy and robustness of RTA. In this new nonlinear Ho filter, the stochastic spherical-radial integration rule is incorporated with the framework of the derivative-free Ho filter for the first time, and the resulting simultaneously attenuates the negative effect in estimations caused by significant nonlinearity and large uncertainty. Comparisons between the SIHeOF and previously well-known methodologies are carried out by means of numerical simulation and a van test. The results demonstrate that the newly-proposed method outperforms the cubature Ho filter. Moreover, the SIH,F inherits the benefit of the traditional stochastic integration filter, but with more robustness in the presence of uncertainty.