分析了盖革模式雪崩光电二极管(APD)工作原理,利用采样间隔内等长时间片的方法,建立了盖革模式APD的激发概率模型。在此基础上进一步分析了光子计数探测概率以及噪声模型,根据噪声模型给出了探测虚警率;针对漫反射和镜面反射两种类型目标,分析了两种反射表面的回波信号模型,结合噪声模型,最终得到了混有噪声信号的光子计数探测概率模型,并且计算了一定阈值条件下的探测概率。 The working principle of Geiger mode avalanche photodiode (APD) is analyzed. The excitation probability model of Geiger mode APD is established by using the method of equal length time slice in sampling interval. On this basis, the probability of photon detection and noise model are further analyzed, and the detection false alarm rate is given according to the noise model. For both diffuse and specular targets, the echo signal models of the two reflecting surfaces are analyzed, Finally, the photon counting probabilistic model with mixed noise signal is obtained, and the probabilities of probing under a certain threshold are calculated.