多视场星敏感器近地轨道自主定位导航方法

传统航天器自主天文导航需要星敏感器、红外地平仪、磁强计等多种敏感器采集导航数据，增加了航天器的成本和复杂度。利用多视场星敏感器的特点，分别对恒星与地球进行成像，在完成姿态测量的同时，得到地心矢量信息，从而进行自主天文导航。首先建立地球几何模型，结合航天器轨道参数与多视场星敏感器的安装布局，实现各个视场内地球边缘的成像模拟，使用Steger 算法提取地球边缘。综合考虑地球扁率的影响，对不同视场中观测到的地球边缘进行拟合得到精确地心矢量，最后进行基于星光角距的直接敏感地平导航仿真。仿真结果表明，在一个视场观测恒星，另外两个视场观测地球边缘的布局情况下，地心矢量精度和导航位置精度分别达到0.017 2（1）和190 m（1）。

Autonomous orientation for LEO spacecraft using multi-FOV star tracker

The traditional methods for spacecraft autonomous navigation need several sensors, such as star sensor, infrared horizon sensor and magnetometer, to collect navigation data. As a result the load of spacecraft will gain in weight, size and power. Based on the advantages of multi-field of view (FOV) star tracker, an autonomous navigation method was proposed which used multi-FOV star tracker (MFST) to image the star and the earth respectively and got the orientation vectors of them. Combining with the orbit parameters of the spacecraft and the layout of the MFST, a mathematic model of the earth imaging was set up to implement the earth edge images in every single FOV. The Steger method was used to determine the earth edge in the images. Considering the earth oblateness, the orientation vector of the earth will be obtained through circle-fitting the earth edge points in each FOV. With the configuration that one FOV measures the navigation star and the other two FOV measures the earth edge, the autonomous orientation based on the starlight angle is simulated and the result indicates that the accuracy of the earth vector and the spacecraft position respectively reaches 0.017 2(1) and 190 m(1)。