激光主动侦测系统探测能力分析

摘要

An active laser detection system could detect and recognize cat ’ s eye targets at long distance .Detection capability analysis was the basis of system design .To assess the detection capability , a mathematical model of the system ’ s signal-to-noise ratio ( SNR ) was established based on laser echo power .The dependence of SNR on several factors , such as receiving optical lens diameter , laser peak power , laser divergence angle , defocusing distance was quantitively analyzed .The results show that at a certain distance , the detector noise comes mainly from shot noise and background noise which surpass dark current noise and thermal noise at least 2 magnitudes .The most effective way to improve detection capability is to use lasers with small divergence angles .The result is helpful for the design of active laser detection systems .%激光主动侦测系统可实现远距离“猫眼”目标的成像探测与识别，探测能力分析是系统设计的前提和基础。为了评估激光主动侦测系统对猫眼目标的探测能力，以激光回波功率为基础，建立了系统信噪比的数学物理模型。分析了影响探测能力的因素，数值模拟了信噪比与接收光学镜头直径、发射激光峰值功率、激光束散角以及等效反射面离焦量的定量关系。结果表明，在一定作用距离范围内，散粒噪声、背景噪声与暗电流噪声、热噪声相差至少2个数量级，系统噪声主要来源于散粒噪声及背景噪声；提高系统探测能力最为有效的方法是选用激光束散角小的光源。这一结果可用于指导激光主动侦测系统的设计。