激波辐射对红外成像探测影响的抑制方法研究

带有红外成像系统的大气层内高速飞行器的头罩窗口外激波的热辐射将降低系统的探测性能。采用单线组模型描述激波的辐射特性。由于激波辐射相对成像系统是近场辐射，建立相应的模型，计算了激波辐射在探测器阵列上产生的光子辐射照度，还计算了激波对目标辐射的吸收特性。得到了如下的计算结果:激波辐射在探测器阵列上产生的背景辐射可以近似为均匀的背景辐射；激波对目标辐射的吸收可以忽略；激波辐射具有强烈的光谱选择性。根据激波的这些辐射性质，在成像系统中通过分别选用不同的带通滤光片，不改变成像系统工作波段的波长宽度，而仅改变其位置，可以减小激波辐射对目标探测的影响，提高探测的信噪比。

Method of mitigating shock layer radiation effect on detection performance of an IR imaging system

Radiation from shock layer near a window of an IR imaging detection system carried by an endo-atmospheric high-speed flying vehicle can degrade detection performance of the system. Single Line Group Model (SLG Model) was selected to describe radiation characteristic of the shock layer. Because the shock layer radiation was near field radiation to the imaging system, a relevant physical model was constructed to calculate photon irradiances caused by the shock layer radiation in the detector array. Absorption characteristic of the shock layer to target radiation was also calculated. Calculation results show that background radiation caused by the shock layer radiation in the detector array is nearly uniform and the target radiation absorbed by the shock layer can be neglectable. The magnitude of the shock layer radiation varies greatly with wavelength. In the imaging system, respective selection of different optical bandpass filters can change position of the working wave band of the system without changing wavelength width of the working wave band. According to the characteristics of the shock layer radiation, the change of the working wave band can mitigate the shock layer radiation effect on target detection and improve signal-to-noise ratio of target detection.