深空探测光学导航敏感器在轨几何定标方法

On-orbit Calibration Approach for Optical Navigation Sensor in Deep Space Exploration

光学导航敏感器是光学自主导航的一个核心器件,它所获得的导航目标源的光线指向的精度将直接影响自主导航的精度。设计了一个分步式的光学导航敏感器在轨几何定标方法,该方法先求解外定标参数,然后在外定标所确定的广义相机坐标系下求解内定标参数,从而完成对内外定标参数的标定。为了在星上计算资源与能力有限的环境下,利用更多的参考星图实现对定标参数的高精度估计,利用逐行法化最小二乘方法估计定标参数。实验表明,通过高精度的在轨几何定标,可以有效提高光学导航敏感器的指向量测精度,使其满足光学自主导航的需求。

Optical navigation sensor is a core instrument in optical autonomous navigation, the accuracy of the direction of light of the navigantion target it acquired will affect the accuracy of autonomous navigation directly. In this paper, a stepwise on- orbit geometric calibration approach for optical navigation sensor is designed. Firstly, the external calibration parameters are solved. Then, the internal calibration parameters are sovled in the general camera coordinate system determined by external calibration. Because the computation source and ability is limited in the satellite, in order to using more star images to achieve estimation of calibration parameters with high accuracy, a line-by-line orthogonalization method based on least square is adopted in calibration parameter estimation. The experiments demonstrates that the on-orbit calibration approach proposed in this paper can improve the pointing accuracy of optical navigation sensor, and make it meet the requirements of optical autonomous navigation.