基于信息融合的大椭圆轨道卫星组合导航方法

An Information Fusion Based Integrated Navigation Method for Highly Elliptical Orbit Satellite

为了实现大椭圆轨道卫星自主、连续的导航信息输出,提出了一种天文导航与GPS导航相结合的组合导航方法。单纯的以星光仰角为观测量的天文导航方法在近地点由于动力学特性变化剧烈,其导航精度严重下降。而能够实现高精度导航的GPS导航方法,受到导航卫星高度的限制,GPS信号无法较好地覆盖远地点。考虑到两种方法的特点,本文采用UKF滤波方法进行信息融合。当卫星进入近地点附近,主要通过GPS实现精确导航,同时通过信息融合修正估计方差阵,进而对天文导航估计进行修正。当卫星在远地点时,则主要采用天文导航方法。仿真结果表明,所提出的组合导航方法,能够弥补两种导航方法的不足,实现整个卫星在轨运行中自主、连续的导航信息输出,其导航精度较单纯的天文导航方法提高61.2%～82.7%。

In order to realize autonomous and continuous navigation information outputs, an integrated navigation system based on celestial navigation and GPS navigation is proposed. Since the celestial navigation method based on star- earth angle observation is vitiated due to severely dynamics change around perigee, the navigation accuracy declines seriously. Moreover, the GPS navigation method with high estimate accuracy in the near-earth space can not cover the apogee due to the altitude limitation of GPS satellites. In this paper, both celestial and GPS navigation outputs are fused by the UKF filter. When the satelhte is near the perigee, the GPS navigation is introduced to achieve accurate navigation. At the same time, the estimate eovariance is revised through information fusion to improve the celestial navigation estimate. When the satellite is near the apogee, the celestial navigation method plays the major role in navigation process. Simulation results show that the proposed integrated navigation method can overcome the disadvantages of the two navigation methods, and achieve autonomous and continuous navigation information outputs during on-orbit operation. The navigation accuracy is improved by 61.2% - 82.7% compared with the only celestial navigation method.