星敏感器图像模拟及目标背景运动特性分析

Image Simulation of Star Sensor and Movement Characteristic Analysis of Background and Target

考虑了星敏感器的方位和俯仰角度,给出了一种星空背景和目标的星敏感器序列图像模拟方法。利用TLE轨道根数与SGP4/SDP4模型计算出星敏感器和目标的精确位置和速度。考虑了传感器坐标系、星体坐标系、2000.0地心惯性坐标系三者的关系,对背景和目标分别计算其在CCD中的成像位置和灰度值并叠加生成序列图像。最后在图像仿真的基础上,分析了图像中背景与目标的运动性质。对背景和目标在图像中运动性质的分析结果对于弱小目标图像检测问题的解决也有帮助。

Considering azimuth angle and elevation angle of star sensor, a new method about images simulation of star sensor was presented. Firstly, exact speed and position of star sensor platform and target were computed by NORAD TLE data and the SGP4/SDP4 model. Secondly, the relations of sensor coordinate system, spacecraft body coordinate system and J2000 geocentric inertial coordinate system were considered. Then the precise position and gray value of stars and targets in CCD images were computed, and sequence images were generated by accumulating stars image and target image. Finally, according to simulation result, movement characteristics of stars and targets in images were analyzed. The method is more reliable than traditional methods. The movement characteristic analysis is effective for dim target and helpful to detect target in star sensor images.