Statistical properties of the back-scattered signals from ground in laser radar applications
地面对激光雷达信号散射的统计研究

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.