为了提高脉冲激光雷达的测距精度，研究了光束在空域为高斯光束、时域为钟型脉冲的激光雷达在恒电压幅度鉴别模式下，回波信号幅度变化和宽度变化对测距精度的影响。证明在一定范围内，由回波幅度变化所造成的测距误差与由回波脉宽变化引起的测距误差，随鉴别电平的取值不同，呈现出相反的变化趋势，即最佳信号门限比的存在，并导出了相应的计算公式。通过改变接收信号强度，对不同信噪比、不同信号门限比条件下大量测距实验结果进行了分析，验证了最佳信号门限比的存在。在一定的实验条件下，最佳信号门限比的取值在1．8附近，实验结果与理论计算吻合良好。这一研究结果为不同应用条件下，激光雷达鉴别电平的合理选取提供了依据。

In order to improve the ranging accuracy of a lidar,the effect of amplitude and width of the echo signal on the ranging accuracy of a lidar with bell-type laser pulses in temporal domain and Gaussian pulses in spatial domain,was studied under the condition of constant-voltage-amplitude discrimination. For different discrimination level,the range error induced by the variation of amplitude and width of echo signal exhibited reverse variant tendency. As a result,the concept of optimum signal threshold ratio was proposed to improve the ranging accuracy of the lidar and its computational formula was also presented in this paper. Further more,the existence of the optimum signal threshold ratio was verified through experiments under different signal threshold ratio and the,experiments showed that the optimum signal threshold ratio of our lidar was about 1.8.The study results provide the basis for the reasomable selection of the lidar to identify the level under different application conditions.