舰船尾流场激光偏振探测机理研究

The studies on laser polarization scattering mechanism, detection model and experimental is an important part of the optical properties of physics research for ship wakes field and is an important foundation for the studies of the underwater remote detection ang the target detection and the identification of the target feature. It is an important tool to improve the probability of detection and lower false alarm rate. First, this study will intend to expand the two-phase model of wake field to a four-phase model. The impacts of the bubble deformation, the turbulent field will be considered to polarized laser scattering. Based on overlapping T-matrix theory, ray tracing theory, vector radiative transfer theory and stratified random medium VRT theory, the four-phase model of the laser polarization scattering mechanism will be studied. On this basis, though the establishment of the photon collision type random distribution adaptive algorithm, the laser polarization detection overall model of ship wakes will be established with vector Monte Carlo method. Finally, the underwater laser polarization detection experimental system will be built. The above models will be corrected and validated through experiments. The quantitative studies of the relations between the parameters of bubbles, turbulence and seawater and the polarization echo signals will be finished. This study is of great significance for elucidating the mechanism and the law of laser polarization detection for ship wakes and will promote the development of laser-guided torpedo technology. It has important significance of values of academic and engineering applications for underwater laser ranging, underwater laser communication, the underwater laser bathymetry and other fields.

舰船尾流场激光偏振散射机理、探测模型及实验研究是舰船尾流物理场光学特性研究的重要组成部分，也是水下远程探测和目标特性识别研究的重要基础，是提高探测系统探测概率、降低虚警率的重要手段。首先，本课题拟将尾流场两相模型扩展为四相，并考虑气泡形变、湍流场等对偏振激光散射的影响，基于重叠T-matrix理论、光线追迹理论、矢量辐射传输理论、分层随机介质VRT理论研究四相模型激光偏振散射机理。在此基础上，拟通过研究光子碰撞类型随机抽样分发自适应算法，结合矢量Monte Carlo仿真，建立舰船尾流场激光偏振探测模型。最后，拟构建水下激光偏振探测实验系统并开展实验研究，修正、验证上述模型，定量研究气泡群、湍流及海水参数与偏振回波信号的反演关系。本项研究对阐明尾流场偏振激光探测机理及规律有重要意义，对水下激光测距、水下激光通信、水下激光测深等领域也具有重要的学术和工程应用价值。

舰船尾流场激光偏振散射机理、探测模型及实验研究是舰船尾流物理场光学特性研究的重要组成部分，也是水下远程探测和目标特性识别研究的重要基础，是提高探测系统探测概率、降低虚警率的重要手段。.首先，本课题基于Mie散射理论、GOA光线追迹理论和随机取向平均理论，研究了单个微小半径近球形气泡、较大半径椭球形气泡、背景海水等的光散射强度特性和偏振特性。求解得到了散射相位函数、不对称因子及相位矩阵元素随入射角的分布特性。利用随机取向平均法求解了随机取向椭球形气泡的光散射特性，计算得到了不同长短轴比率情况下，随机取向椭球形气泡的平均散射相位函数和平均相位矩阵元素的角分布特性。详细对比分析了尾流气泡与背景海水的相位矩阵元素的差异，验证了采用气泡光散射的偏振特性进行尾流探测和识别的理论可行性。在此基础上，通过研究光子碰撞类型随机抽样算法、碰撞形式随机抽样算法、回波光子偏振贡献接收算法和回波信号偏振信息结果统计算法，结合矢量Monte Carlo仿真，建立了舰船尾流场激光偏振探测模型，研究了多重散射效应、不同接收视场角、不同气泡群密度、不同长短轴比率的气泡群与回波信号的强度及偏振特征的关系。最后，构建了模拟尾流场激光偏振探测实验系统并开展了实验研究，对理论分析进行验证。测量研究了固定距离上气泡群有无两情况的特征、低信噪比回波信号中气泡群位置信息的提取、气泡群密度信息的提取、船底识别和分辨等内容。.本项研究对阐明尾流场偏振激光探测机理及规律有重要意义，对水下激光测距、水下激光通信、水下激光测深等领域也具有重要的学术和工程应用价值。