基于舰船尾流激光雷达的Monte Carlo模型及方差消减方法研究

Monte Carlo model and variance reduction method based on lidar of ship wake

对舰船尾流激光散射机理及探测过程的数值模拟是研究舰船尾流激光探测与制导的重要基础.首先分析了Monte Carlo方法引入到尾流激光雷达数值模拟领域研究的可行性.结合自行研制的尾流激光雷达实际参数,建立了尾流激光探测的Monte Carlo数值仿真模型.通过对仿真结果进行统计,深入剖析了仿真结果方差大及光子利用率低等问题的成因.为解决该问题,基于有偏采样理论和分裂-轮盘赌基本原理提出了接收光学视场内光子强行碰撞方法和以光子自由程总长度为准则的光子分裂方法,并进行了两方法的融合.仿真与实验结果的对比分析表明,提出的模型仿真结果与实验数据符合较好,验证了模型的正确性;提出的接收光学视场内光子强行碰撞方法和光子分裂方法能有效减小方差并提高光子利用率;解决了Monte Carlo方法引入到尾流激光雷达模拟过程中的适用性问题.

The numerical simulation of ship wake laser scattering mechanism and the detection process are important foundations for the laser detection and guidance of the ship wake. The feasibility that Monte Carlo method is introduced into the numerical simulation of lidar of ship wake is analyzed firstly. The Monte Carlo simulation model of laser detection of ship wake is developed with the actual parameters of self-developed lidar of ship wake. The causes of the large variance and low photon utilization of simulation results are in-depth analyzed by statistics on the simulation results. To resolve this problem, the method of photon collision forced in the receive optical fields, the photon splitting method with the total free pach of photon serving as a criterion, and the conbination of the two methods are put forward based on partial sampling theory and the basic principle of division-roulette bet. The comparative analyses of the simulation and the experimental results show that the proposed model simulation results fit to experimental data better, thus the correctness of the model is verified. The photon collision forced in the receive optical field and division-the roulette method can effectively reduce the variance and increase the photon utilization. In this paper, the Monte Carlo method is introduced into the simulation process of lidar of ship wake.