通过实验比较研究了基于SNSPD与SPAD探测器的激光测距系统.实验中, 当接收回波端衰减120 dB时, 天空光背景可忽略, 基于SPAD的激光测距系统探测概率低于0.2%, 而基于SNSPD的激光测距系统探测概率达35%; 当激光发射频率低于1 kHz, 基于SNSPD的激光测距系统探测概率比SPAD高60%以上.研究表明：在探测弱信号回波光子时, SNSPD的探测性能远远优于SPAD, 其原因是SNSPD具有较低的暗计数和高探测概率.与此同时, 在接收端无衰减情况下, 天空光背景会带来暗计数, 影响测距系统信噪比.通过仿真分析表明, 当背景亮度L0高于30 W/(m2·sr)时, 该基于SNSPD的激光测距系统的信噪比低于6, 可能影响测距系统稳定探测.

The laser ranging systems based on SNSPD and SPAD detectors are compared by experiments. In the experiments, the sky light background can be ignored when the receive echo is attenuated to 120 dB, the detection probability of SPAD is less than 0.2%, while the detection probability of SNSPD is 35%. When the laser emission frequency is below 1 kHz, the detection probability of SNSPD is more than 60% higher than that of SPAD. The study shows that the detection performance of SNSPD is much better than that of SPAD when detecting the weak signal echo photons. The reason is that SNSPD has lower dark counts and higher detection probability. At the same time, with no attenuation at the receiving end, the sky light background will bring dark counts, affecting the signal-to-noise ratio of the ranging system. Simulation analysis shows that the signal-to-noise ratio of the SNSPD-based laser ranging system is lower than 6 when the background luminance is higher than 30 W/(m2·sr), which may affect the stability detection of the laser ranging system.