地面对激光雷达信号散射的统计研究

从理论角度研究了利用高斯光束照射远场目标时,激光散斑的统计特性.导出了散射光场的自相关函数和光强度的二阶矩的解析表达式,计算了激光散斑的面积.研究表明:在接收面上,光强的分布与目标表面高度的相关长度和均方根高度密切相关,激光散斑面积和散斑光强的相关系数只与激光束腰的尺度有关,与目标的均方根高度和相关长度无关. 关键词： 激光散斑 自相关函数 高斯分布 协方差

Statistical properties of the back-scattered signals from ground in laser radar applications

The surface roughness dependence of the optical field atuocorrelation function and the intensity autocorrelation function of the speckle pattern, produced in the far field under the illumination of a Gaussian beam, has been theoretically investigated with the assumption that the irregularities of the target surfaces are larger than the laser wavelength. Analytical expressions for the first-and second-order moments of the intensity have been derived, and the size of the speckle cell has been computed. The analysis indicates that the mean intensity of the speckle patterns is closely related to the ratio of the lateral correlation length to the surface root-mean-square height of the surface. Whereas the size of the speckle cell and the correlation degree of the speckle intensities are shown to be independent of the parameters characterizing the roughness of a surface, and only determined by the laser beam waist.