基于事件的高动态星敏感器星点提取方法  

An Event-based Method for Extracting Star Points from High Dynamic Star Sensors

作　　者：曾思康 赵汝进[1,2,3] 马跃博 朱自发 唐雨萍 朱梓建 ZENG Sikang;ZHAO Rujin;MA Yuebo;ZHU Zifa;TANG Yuping;ZHU Zijian(Institute of Optics and Electronics of Chinese Academy of Sciences,Chengdu 610209,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Science and Technology on Space Optoelectronic Precision Measurement,Chinese Academy of Sciences,Chengdu 610209,China)

机构地区：[1]中国科学院光电技术研究所,成都610209 [2]中国科学院大学,北京100049 [3]中国科学院空间光电精密测量技术重点实验室,成都610209

出　　处：《光子学报》2022年第9期343-354,共12页Acta Photonica Sinica

基　　金：中国科学院“西部之光”人才计划(No.YA21K001);四川省西部之光专项,四川省杰出青年科技人才项目。

摘　　要：针对传统帧模式星敏感器在高动态(≥3°/s)下星点质心提取精度低或提取失败的问题,提出一种基于事件的高动态星敏感器星点提取方法。该方法基于事件相机低延迟、高时间分辨率的特性,解决了高动态条件下的运动模糊问题。首先,提出基于时空密度的噪声去除方法,针对事件流进行降噪处理,平均去噪精度在0.85以上,提高了事件信噪比。其次,提出基于均值漂移的星点定位方法,计算星点事件簇的中心作为星点质心。最后,通过不同条件下的仿真实验,验证了所提去噪方法的有效性和鲁棒性,且角速度达到20°/s时,仍可完成星点提取,角速度在3°/s~10°/s时,平均质心误差小于0.04 pixel,角速度达到15°/s时,平均质心误差小于0.1 pixel。Star sensor is a device that relies on measuring the pointing of the navigation star in the spacecraft coordinate system to determine the attitude of the spacecraft,and is the highest precision attitude sensor,whose accuracy can reach the angular second level,with the advantages of no drift,long working life,etc.It is a fundamental and critical device for the survival and performance improvement of spacecraft.It is of strategic importance in space applications such as remote sensing to the earth,deep space exploration and high precision detection.Most of the current star sensors use traditional optical sensors.Conventional star sensors use frame-based imaging modes,such as global exposure and roll-up exposure,which generate a frame of star image within a fixed exposure time(usually 100 ms).However,under the high dynamic conditions of large spacecraft maneuvers,this imaging mode produces motion blur and"star point trailing"effect,which,together with the noise effect,significantly reduces the signal-to-noise ratio of the star map,resulting in lower accuracy or even failure of star point extraction,and severely limits the dynamic performance of the star sensor.Star point center of mass extraction is a crucial part of the star sensor,which is directly related to the final attitude measurement accuracy of the star sensor.The sensitive navigation stars are long-range targets,and their orientations in the celestial coordinate system are highprecision astronomical observations with milliarcsecond accuracy and almost constant,so the final attitude accuracy of the star sensor depends on the extraction accuracy of the star point masses in the digital images.Therefore,the accuracy of the final solution of the star sensor depends mainly on the extraction accuracy of the star point center in the digital image.In the traditional star sensor,the average gray value of the whole image is used as the background noise gray value,and then the background noise is subtracted from the star point region gray value to obtain the corrected

关 键 词：星敏感器 事件相机 质心提取 高动态 时空密度 均值漂移 

分 类 号：V249.31[航空宇航科学与技术—飞行器设计]