太阳对成像型天基激光告警系统的影响

针对成像型天基激光告警系统中的太阳背景辐射问题,通过理论分析和数值计算研究了太阳与系统探测器不同空间位置关系时直射太阳光和地球反射太阳光对系统成像信噪比、威胁激光检测、探测器自身安全的影响.结果表明:太阳光是天基激光告警系统的主要背景辐射,地球反射太阳光是系统红外探测器成像的主要背景光|反射太阳光辐照在探测器像面上的最大能量密度为0.97 mJ/cm2,反射太阳光背景下,攻击激光成像信噪比在103以上,信标激光信噪比小于1,反射太阳光对攻击激光检测没有影响,对信标激光成像是强背景干扰|直射太阳光辐照探测器是系统不可避免的情况,太阳成像光斑功率密度最大时约20 W/cm2,将导致探测器像元饱和甚至损坏|太阳成像光斑特征与入射激光相似,会造成系统严重虚警.

Effects of Sun on Imaging Space-Based Laser Detection System

In view of the problem of solar radiation in the imaging space-based laser warning system,the effects of sunlight on the infrared detector of warning system were studied by theoretical analysis and numerical calculation.On the basis of analysis of the different spatial relationship of sun and detector,the influences of direct sunlight and sunlight reflected by earth to the signal to noise ratio(SNR) of infrared image,laser threat detection,the detector safety were investigated respectively.The results show that the sunlight is the mainly background radiation to space-based laser warning system.The sunlight reflected by earth is the main imaging background light of system′s near infrared detector,and the maximum energy density of reflected sunlight exposuring the CCD is 0.97 mJ/cm2.In the reflected sunlight background,the SNR of attack laser image exceeds 103,for the beacon laser is always below 1.While the reflected sunlight has no effect on attack laser detection,but it is strong background interference to the beacon laser detection.The sunlight direct exposure detector is unavoidable to the warning system.As the maximum energy density of the sun imaging spot is about 20 W/cm2,it will lead to the pixel of CCD saturation or even damaged.Since the imaging spot of sun is similar to the laser,direct sunlight will cause serious false alarm.