提出用星敏感器和地平仪测量星光角距作为主要观测量 ,用地平仪直接测量得到地心方向矢量 ,用间接测得的地心距离作为补充观测量 ,并用推广卡尔曼滤波方法来实时确定航天器的轨道。文中对系统的构成、模型的建立、以及卡尔曼滤波的方法都作了认真的仿真研究 ,并获得了满意的结果 Proposed the star sensor and the horizon to measure the celestial horn as the main observation, the direct measurement of the center of gravity with the geodetic vector, using the indirectly measured geocentric distance as a supplementary observation, and using the extended Kalman filter method to determine Spacecraft orbit. In this paper, the system structure, the establishment of the model, and the Kalman filtering method are carefully simulated and obtained satisfactory results