空间目标天基成像探测信噪比分析

Analysis of SNR for space-based imaging detection of space object

基于光散射理论和轨道动力学,引入区域分解、网格划分和矢量坐标变换的思想,利用双向反射分布函数建立了空间目标等效星等的数学模型。结合空间目标天基成像探测的噪声来源建立了空间目标探测信噪比的数学模型。以空间目标天基红外系统为例,根据目标的结构特性、材料特性、背景特性、轨道特性及探测器的轨道特性、性能参数等,计算了目标等效星等和目标探测信噪比随时间的变化关系。结果表明,目标等效星等在观测时间内存在约3个星等的差别,导致目标探测信噪比在观测过程中也随之变化。仿真结果验证了建模方法的正确性,实现了空间目标天基成像探测信噪比的动态分析。

According to the optical scattering theory and the orbital dynamics, mathematical model of equivalent magnitude of space object was established with Bidirectional Reflectance Distribution Function (BRDF) by region classification, grid division and vector coordinates transformation. Combining with the noise resources in space-based imaging detection of space object, mathematical model of Signal-to-Noise Ratio (SNR) was put forward. On the basis of the structure, material, background and orbit parameters of the object and the orbit and performance parameters of the detector, equivalent magnitude and SNR of the Space-Based Infrared System (SBIRS) were calculated. It shows there is about three magnitudes difference in equivalent magnitude during the observation time, which leads to the correlated variation of SNR. The simulation results illustrate the validity of modeling method. The dynamic analysis of SNR for space-based imaging detection of space object is achieved.