针对空中快速运动目标远距离成像探测的需求，推导了适用于点目标的光子级激光主动成像探测公式，搭建基于64×64 像元Gm-APDs 的光子级成像探测系统，通过低频成像探测实验，实现对4.3 km 处点目标的成像探测。实验结果表明，基于Gm-APDs 的低频、光子级回波激光成像探测技术，在无需长时间、多次累积探测的情况下，实现对点目标快速成像探测。为破解对远距离、空中快速运动目标的主动成像探测技术难题奠定基础。

A photon-level imaging-detection system is developed based on 64?64 pixel Geiger-mode avalanche photodiodes(Gm-APDS). By performing a low-frequency imaging-detection test, imaging detection of a point target 4.3 km away is realized. The experimental results show that the low-frequency photon-level echo laser imaging-detection technology based on Gm-APDS can quickly image and detect point targets without requiring long-term and multiple cumulative detections. This study lays a good technical foundation for the active detection of long-distance fast-moving targets in air.