构造折射星场方法用于星光折射导航仿真的研究

Artificial Refracted Star Field Method in Simulation of Autonomous Navigation by Stellar Refraction

针对星光折射导航算法研究时星图模拟与匹配复杂的问题,提出一种构造折射星场的方法用于导航算法研究和评估。通过对星光折射几何关系的研究,得到一颗满足几何关系的折射星,再将它绕地心矢量方向旋转得到其他满足条件的折射星,构造折射高度均为25km的折射星场,解决了仿真研究时对星图的需求问题。建立带摄动的航天器运动方程,利用扩展卡尔曼滤波算法和构造出的星场进行导航仿真。仿真结果表明,观测到的折射星之间的角距接近于或小于星敏感器的精度时,无法进行星光折射导航;当观测到3颗星的持续时间大于等于0.8s时,该导航系统的三轴位置误差均小于139m,证实了构造折射星场方法的有效性。

Aiming at the complex star pattern simulation and recognition when carrying out the research of autonomous satellite navigation based on stellar refraction,an approach of artificial refracted star field is put forward.Through the study of starlight refraction geometry,one special refracted star which satisfies the geometry is firstly achieved,then other stars can be achieved by rotating this star around the earth-satellite vector.The star field is established and it is made up of stars whose starlight is refracted at the altitude of 25 km in the atmosphere.Finally,system equation which is established with orbit perturbations and expanded Kalman filter algorithm as well as the artificial refracted star field are used in the navigation simulation.The results show that when the angular distance between the two refracted stars is close to or less than the accurracy of the star sensor,navigation is not able to be carried out.And the accuracy of every single axis is better than 139 m when simultaneously observing three refracted stars for 0.8 s or more,thus validating the effectiveness of the artificial refracted star field method.