为了实现大椭圆轨道卫星在整个轨道上的自主导航,提出了一种天文导航与雷达高度计测高相结合的组合导航方法.由于大椭圆轨道卫星在近地点动力学特性变化剧烈,单纯的以星光仰角为观测量的天文导航方法精度严重下降.雷达高度计能够直接获得高度测量,但是受其体积和功率的限制,测量范围仅为1000 km以下的高度.考虑到两种方法的特点,采用两种方法的组合导航方案,利用UKF滤波方法进行导航估计.当卫星进入近地点附近,其高度小于1000 km时,在天文导航中引入雷达高度计测量实现精确导航；当卫星在远地点时,则仅采用天文导航方法.仿真结果表明,所提出的组合导航方案,能够充分结合两种导航方法的特点,实现大椭圆轨道卫星自主,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约68.9％.%In order to realize autonomous navigation of highly elliptical orbit satellite, an integrated navigation system based on celestial and radar altimeter navigation method is proposed. Since the dynamics of highly elliptical orbit satellite changes severely around perigee, the precision of celestial navigation method based on star-earth angle observation declines seriously. Though the orbit height can be measured by radar altimeter, the measuring range is less than 1000 km due to the limitation of size and power. To make full use of the methods, the integrated navigation system is composed by both the celestial and radar altimeter methods, and the UKF algorithm is used to estimate the navigation information. When the satellite is near the perigee and the height is below 1000 km, the radar altimeter measurement is introduced as additional observation to celestial navigation. When the satellite is near the apogee, only the celestial navigation method is used in navigation process. Simulation results show mat the proposed integrated navigation method can make full use of the two navigation methods, and achieve autonomous and continuous navigation information outputs. The navigation precision is increased 68.9% compared with that only by celestial navigation.
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