中文摘要：

信噪比是激光雷达辐射能力的表征,是度量激光雷达回波信号品质的重要参数,对信噪比的评估一直是研究者面临的问题。针对大气探测激光雷达,对激光雷达回波信号噪声比例因子（NSF）和信噪比进行了分析研究;通过自行研制的532 nm瑞利散射激光雷达的昼夜连续观测,对噪声比例因子进行了估算,计算得出实验激光雷达系统噪声比例因子在白天和夜间分别为0.07和0.034;采用白天噪声比例因子值对激光雷达回波信号信噪比进行了估算,计算结果表明：基于噪声比例因子的信噪比估算法可较好地估算出系统回波信噪比。该方法为大气激光雷达系统总体设计和大气参数反演提供了数据依据。

英文摘要：

The signal-to-noise ratio（SNR） of Lidar（light detection and ranging） reflects its radiance and is one of the most important parameters for evaluation of lidar return signal quality. However, it is very difficult to estimate the value of SNR quantitatively in practical engineering. At the first, the algorithm was used to estimate lidar returns noise scale factor（NSF） and SNR. Then, the value of NSF of the Rayleigh lidar were estimated by measuring 0-40 km atmosphere day and night with 532 nm wavelength laser, which is 0.07 in daytime and 0.034 in nighttime. Finally, the SNR of the atmospheric lidar was estimated by the value of NSF in daytime. Result shows that the method which based on the NSF in nighttime of lidar to estimate the value of SNR is feasible. The evaluating of NSF and SNR of the lidar can be used as the basis for its overall design and inversion.