基于分形的大气湍流随机相位屏数值模拟

激光大气传输湍流效应是制约合成孔径激光雷达高质量成像的重要因素之一,对大气湍流统计特性进行了研究,建立了大气湍流随机相位屏分形模型,使用随机中点位移法进行模拟,分别产生了符合Kolmogorov及non-Kolmogorov统计规律的湍流相位屏.通过计算模拟相位屏的相位结构函数,与理论值比对,验证模拟相位屏的准确性,并与现有的谱反演法和结构函数法进行了对比,分析了各自的优缺点.结果表明,基于分形方法产生的相位屏与理论值更加接近,效果良好.

Numerical Simulation of Phase Screen Distorted by Atmospheric Turbulence Based on Fractal Theory

Accurately simulating the effect of atmospheric turbulence on the laser beams will improve the imaging ability of practical synthetic aperture ladar. A formalism to model the phase screen(PS) distorted by atmospheric turbulence based on fractal theory is provided. The random midpoint motion(RMM) algorithm is introduced and used to simulate the phase screens corresponding to Kolmogorov and non-Kolmogorov turbulence respectively. Simulation accuracy evaluation is carried out by comparing the phase structure function and the theoretical results. Power spectrum method and structure function method are also used. Results show that RMM algorithm can give a better approximation to the theoretical value.