中文摘要：

火星探测器经过近火点制动进入大椭圆环绕轨道后,要求能够自主确定探测器的位置、速度等导航信息。提出了一种基于陆标和X射线脉冲星测量的自主导航方法。该方法针对火星大气辅助减速的大椭圆轨道,提出在近火点使用陆标导航,在离开火星大气后的高轨道段使用脉冲星导航。利用星上光学敏感器获得火星陆标信息和X射线敏感器测量脉冲星信号,通过扩展卡尔曼滤波方法（EKF）进行滤波处理得到探测器位置。在现有导航敏感器水平下,该组合导航方法能够取得近火点100 m,远火点1 km的导航精度。该方法实现了两种导航方式优势互补且精度高,为火星环绕段自主导航提供了一种新思路。

英文摘要：

Mars probe after brake automatically enters around a large oval orbit, requires the ability to independently determine the position of the detector, speed navigation information. A new autonomous navigation method based on landmarks measurements and X-ray pulsar measurements was proposed.Aimed at the elliptical orbit when brake passing through atmosphere, the landmarks-based navigation was used at perigee and X-ray pulsar-based navigation was used at apogee. According to the principle and measurement of pulsars and landmarks navigation, the extended Kalman filter（EKF） was designed to get the navigation information. Under the existing navigation sensor level, the integrated navigation system can get near the perigee 100 m, 1 km far from the apogee of the navigation accuracy. Simulation results show that this method was a promising and attractive scheme for autonomous navigation of Mars circle satellites.