姿态关联帧星敏感方法误差机理研究

The attitude accuracy of a star sensor decreases rapidly when star images become motion-blurred under dynamic conditions. Since the star sensor is the best choice as an attitude sensor in the fields of deep space exploring, satellite and etc. Thus, the attitude accuracy improving methods are become a research hot spot. The exiting techniques focused on a single star image frame to solve this problem and improvements are obtained at a certain extent. An attitude-correlated frames (ACF) approach, which focuses on the features of the space attitude transforms of the adjacent star image frames, has been proposed by our group to improve upon the existing techniques. With the ACF method, a much larger star image frame is obtained through the combination of adjacent frames. As a result, the effect of motion-blurring and the error of the star centroid are reduced. The improvement of the attitude accuracy is approximately proportional to the square root of the number of correlated star image frames. We are going to focus on the research of the theory of the ACF approach. The processing method of a single motion-blurred star image frame is one of the main missions as well. Finally, simulations and experiments will be implemented to verify the related algorithms.

运动模糊导致动态条件下星敏感器的测量精度显著降低，但星敏感器在深空探测、卫星导航等领域的广泛应用及其不可替代性的地位与作用，促使人们研究高动态环境下星敏感器姿态测量精度进一步提升的新方法。现有技术都聚焦在单帧星图上，采取措施改进其性能，并收到了良好的效果。本项目在利用现有技术基础上，立足于星敏感器图像序列中帧与帧之间的空间姿态关联特性，采用本课题组提出的姿态关联帧（Attitude Correlated Frame，ACF）处理方法，将图像序列中的星图帧合并成一幅巨大的星图进行匹配处理，可有效抑制星点提取噪声和运动模糊的影响，其抑制能力与关联帧数量的平方根近似成正比。本项目将对姿态关联帧方法的理论与算法进行深入研究，同时研究动态条件下星敏感器单帧星图的预处理方法，最后对相关算法进行仿真与实验验证。

星敏感器广泛应用在深空探测、卫星导航等领域，为航天器提供高精度姿态信息。项目重点围绕姿态关联帧（ACF） 方法的误差机理展开研究，基于星敏感器图像序列中帧与帧之间的空间姿态关联特性，提出了一种动态环境下提高星敏感器测量精度的方法，并对其误差机理开展了深入研究，并完成了相关的试验验证。首先分析了星敏感器的动态误差特性，提出了基于数学形态学的星图预处理算法和区域限制的模糊星点分割与复原方法，可有效增强动态条件下星点的信噪比，提高星点提取精度和识成功率。深入研究了星敏感器姿态关联帧方法的误差理论与方法改进，以课题组研制的高精度激光陀螺捷联惯导系统为实验平台和参照对象，搭载于在某试验舰上进行了试验验证，试验结果表明可有效抑制星点提取噪声和运动模糊的影响，应用 ACF 方法且关联帧数量为16时解算得到的姿态测量结果，其光轴指向误差和横滚角误差分别为4.07 角秒（1σ）和4.61角秒（1σ），达到了本项目研究所要达到的技术指标。