白天激光漫反射测距中微弱信号检测的单开门多触发方法

白天激光漫反射测距因存在强背景噪声,导致微弱回波信号的检测十分困难,严重限制了激光漫反射测距的广泛应用。因此,提出了采用单开门多触发方法解决白天激光漫反射测距的微弱信号检测难题。首先,介绍了一种GM-APD (Geiger-ModeAvalanchePhotoDiode,盖革模式雪崩光电二极管)多触发概率分布函数的快速求解方法。接着,取激光漫反射测距系统典型参数,理论分析了多触发情况下的回波信号检测概率,分析结果表明单开门多触发方法可提高激光漫反射测距在白天情况下的回波信号检测概率。同时,通过对触发次数限制的优选,可以增加有效检测比,减少白天观测条件下回波信号的提取代价。最终,通过系统仿真验证了理论分析结果的正确性。因此,单开门多触发方法是解决白天激光漫反射测距微弱信号检测的可行途径之一。

Multi-Hit Method for Weak Signal Detection of Diffuse Reflection Laser Ranging in Daylight

The weak echo signal in diffuse reflection laser ranging is very difficult to detect in daylight because of strong background noise, and this limits the extensive application of diffuse reflection laser ranging. In this paper,a multi-hit method is proposed to solve the problem. First, a fast performance prediction method for multi-hit GM-APD (Geiger-Mode Avalanche PhotoDiode) is introduced. Then, the detection probability of echo signal is analysed under different firing times based on the typical parameters of a diffuse reflection laser ranging system. Furthermore, effective detection ratio is defined to evaluate the extraction cost of echo signal. Theoretical analysis shows that processing only a few firings in one gate window can result in large increase of detection probability for diffuse reflection laser ranging in daylight. Meanwhile, optimization of firing time for GM-APD can increase effective detection ratio and reduce extraction cost of echo signal. Finally, the correctness of theoretical analysis is verified by system simulation. Therefore, the multi-hit method is one of the feasible ways to detect the weak echo signal of diffuse reflection laser ranging in daylight.