一种利用地球敏感器的星光导航方法

针对直接敏感地平的红外地平仪-星光导航系统精度低的问题，提出通过建立扁率误差补偿函数，研究扁率引起的姿态角测量误差；建立地心矢量的姿态角误差模型，通过修正地球扁率误差来补偿姿态角，对卫星施加姿态偏转指令调整地心矢量偏移。同时基于SODERN地球红外辐射模型，考虑红外辐射强度随纬度和季节的变化建立真实红外辐射曲线，通过滤波算法获得精确的地球切线边缘的量测信息，提高红外地平仪测量精度。仿真结果表明，该方法有效提高了基于红外地平仪的星光导航定位方法的可靠性和精度，导航位置误差能达到500m左右，较原有系统提高3倍以上。

A Method of Starlight Navigation Using the Infrared Horizon Sensor

In order to reduce the influence of infrared horizon sensors on starlight navigation precision, the research on measuring errors of attitude angle caused by Earth oblateness is presented by developing the compensation function of oblateness. Meanwhile, the error model of attitude angle based on geocentric vector is designed. The geocentric vector is modified by correcting the inaccuracy of the oblateness, and the geocentric vector offset is adjusted by the attitude control instructions for the satellite. According to the SODERN’s Earth infrared radiation model, the real infrared radiation curve including the changes of the infrared radiation intensity with latitude and season is established, thus the accurate information of the Earth edge is obtained by means of filtering algorithm. Moreover, the measuring accuracy of the infrared horizon sensors can be improved effectively. Simulation results show the validity of the proposed strategy to improve the reliability and precision of the starlight navigation based on the scanning infrared horizon sensor. The navigation position error is 500m, which means the precision is triple better than the traditional method.