基于模型和样条的星敏感器在轨自标定方法  

On-Orbit Self-Calibration Method for Star Sensors Based on Models and Splines

作　　者：闫浩东 支帅 陈旭睿 李照雄 丁国鹏 张洋洋 张永合 朱振才 Yan Haodong;Zhi Shuai;Chen Xurui;Li Zhaoxiong;Ding Guopeng;Zhang Yangyang;Zhang Yonghe;Zhu Zhencai(Key Laboratory of Satellite Digitization Technology,Innovation Academy for Microsatellites of Chinese Academy of Sciences,Shanghai 201210,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Information Science and Technology,ShanghaiTech University,Shanghai 201210,China)

机构地区：[1]中国科学院微小卫星创新研究院卫星数字化重点实验室,上海201210 [2]中国科学院大学,北京100049 [3]上海科技大学信息科学与技术学院,上海201210

出　　处：《光学学报》2024年第12期254-262,共9页Acta Optica Sinica

摘　　要：星敏感器长期在轨运行时,畸变会逐渐积累,因此对星敏感器进行在轨标定很有必要。目前,大多数星敏感器在轨标定算法仅依赖于星间角距的不变性,并需要较长的标定时间。本文算法的创新性在于利用星间角距关系和星点像素位置关系,将畸变信息解耦为粗校准的参数化信息和精校准的非参数化信息。充分考虑到星敏感器的工作性质,利用B样条算法的特点,使得连续的在轨校正仅需极少的时间。相较于目前常用的地面标定算法,本文算法在实现更准确的星点位置校正和更精确的姿态输出精度的前提下,训练完全部数据只需要几百毫秒的时间。在经过本文算法的标定后,在轨星敏感器的星点位置偏差由0.55766 pixel降低为0.23706 pixel,测量精度由5.857″提高到2.775″,这为未来低成本卫星搭载非专业化设计的星敏感器提供了一定的算法参考。Objective Lens distortion is a common problem in the optical system of star sensors.Vibrations during launch,changes in the space thermal environment,and other factors may cause changes in the optical system and lead to lens distortion.The changes in the optical system include the refractive index changes of optical materials,the thickness,curvature radius,and surface shapes of optical lenses,and the distance changes between optical elements.These distortions can change the focal length and principal point and can cause various nonlinear distortions of the optical system,leading to errors in the angle information obtained in the star sensor,thereby affecting the accuracy of navigation and attitude control.These errors may accumulate in long-duration missions and lead to poor system performance.Therefore,eliminating lens distortion and improving the measurement accuracy of star sensors become necessary for maintaining the attitude output accuracy of star sensors.Methods In response to the accumulation of lens distortion in star sensors due to mechanical vibrations,temperature changes,radiation,and solar radiation pressure during launch,as well as poor attitude accuracy caused by the optical distortion of uncalibrated low-cost cameras,we creatively introduce the non-parameterized B-spline algorithm into the widely used model-based correction algorithm.This approach decouples lens distortion into parameterized coarse calibration and non-parameterized fine calibration.The main advantage of B-spline curves is their flexibility and local controllability.Compared to the traditional interpolation methods,the shape of B-spline curves can be controlled locally by adjusting the positions of control points without affecting the entire curve.In the coarse calibration stage,the Levenberg-Marquardt algorithm is introduced to optimize the principal point and focal length,and the results are used as parameters for data preprocessing.Additionally,the right ascension,declination,and rotation angle of each frame image are also used

关 键 词：星敏感器 光学畸变 在轨标定 B样条算法 图像处理 

分 类 号：V241[航空宇航科学与技术—飞行器设计]