基于H_∞的低精度捷联惯导系统初始对准方法

An Approach for Initial Alignment of Low-accuracy SINS Based on H_∞ Filter

由于低精度捷联惯导系统的陀螺精度较低,初始对准时方位失准角的估计精度往往不高;另外,进行初始对准的常用方法是采用Kalman滤波技术,但在实际应用时,其鲁棒性不高,因此迫切需要一种能够改善低精度捷联惯导系统方位失准角的估计精度且兼具鲁棒性的初始对准方法。提出了一种将H∞滤波用于引入磁航向的低精度捷联惯导系统的初始对准方法,能够解决上述问题。建立了一种引入磁航向的捷联惯导系统初始对准的误差模型,通过可观测性和可控性分析,得出可观可控系统,利用H∞滤波方法对其进行了仿真分析,仿真结果表明,能够改善低精度捷联惯导系统方位失准角的估计精度,并能有效抑制有色噪声及建模误差的影响,将其应用于低精度捷联惯导系统的初始对准是切实可行的。

Because of the low precision of gyros in low - accuracy SINS, the accuracy of estimate of azimuth angle misalignment is not very high; and the Kalman filter is commonly used in initial alignment, which shows low robustness in practical application, thus an approach which can improve the accuracy and robustness for initial alignment of low - accuracy SINS is urgently needed. Through the introduction of magnetic heading,a new method of ini- tial alignment has been developed for low - accuracy SINS by using H∞ filter, which can solve the problem. An error model of SINS with magnetic heading is proposed. The observability and controllability of the model are analyzed, and it is concluded that the system is observable and controllable. The H∞ filter is designed, and the simulation results illustrate that this method can restrain colored noises and modeling error effectively. This approach can be used in initial alignment of low - accuracy SINS.