基于蒙特卡罗方法的波动水面对激光水下目标探测的影响

机载海洋激光雷达在探测水下目标时,水面波动会影响向下传输的激光光束质量。基于蒙特卡罗方法定量分析了光子在目标平面上的空间分布,以及光子返回海气界面的空间分布和时间分布。模拟结果表明,随着风速的增加,光子在目标平面上的空间分布越来越偏离高斯分布;而光子返回海气界面的空间分布则严重偏离高斯分布,且风速的影响已经不再占主导地位。根据计算获得的光子返回海气界面的时间分布,发现当风速较大时,激光雷达的探测深度降低。

Influence of Wavy Sea Surface on Laser Detection of Underwater Target with Monte Carlo Method

When airborne lidar is detecting the underwater target, the laser beam will be influenced by the wavy sea surface. Based on Monte Carlo method, the space distribution of photons on the target surface is quantitatively analysed and the space distribution and time distribution of the photons return which the sea-air interface are analysed. Simulation results show that the space distribution of photons at the target surface gradually deviates from Gauss distribution as the velocity of wind increases and the space distribution badly of the photons which return the sea-air interface deviates from Gauss distribution. The influence of wind velocity is no longer important. By computing the time distribution of photons which return the sea-air interface, it is found that when the wind velocity increases, the detection depth of lidar decreases.