最大探测距离是表征光子雷达性能的重要参数，本文利用盖革模式雪崩光电二极管阵列对直接探测脉冲光子雷达的最大探测距离进行了研究。从激光雷达方程出发，根据盖革模式雪崩光电二极管阵列探测像元中回波激发初始电子数的泊松统计模型和系统最小可接受探测概率条件，建立了光子雷达的最大探测距离理论模型。利用光子雷达系统设计参数，研究了对最大探测距离产生影响的五个主要因素。研究结果表明发射激光脉冲能量越高，噪声越小，回波位置在距离门中越靠前，大气传输系数越大，目标反射率越高，获得的最大探测距离越大；使用脉宽为 5 ns，脉冲能量为 50 μJ的激光脉冲，最小可接受探测概率为 0.9时，可获得大于 1 km的最大探测距离；同时，选择合适的系统最小可接受探测概率对系统探测性能的改善十分重要。

Maximum detection range is an important parameter for evaluating the performance of photon ladar. In this paper, the maximum detection range of direct-detection pulse photon ladar which uses Geiger-mode Avalanche Photodiode (GM-APD) array as the detector is investigated. Based on the laser radar equation and the model of the minimum acceptable detection probability, and assuming the primary electrons triggered by the echo photons in the GM-APD pixel obey Poisson distribution, the theoretical model estimating the maximum detection range is proposed. By using the system design parameters, the influence of five main factors on the maximum detection range is investigated. The results show that the stronger emitted pulse energy, lower noise level, front echo position in the range gate, large atmospheric transmission, and high target reflectivity can result in larger maximum detection range. When the minimum acceptable detection probability is selected to 0.9, by using emitted laser pulse with pulse width 5 ns and energy 50 μJ, the system maximum detection range more than 1 km can be achieved. At the same time, it is important to select the minimum acceptable detection probability for producing a high system detection performance.