Numerical simulation of beam propagation through atmospheric turbulence for laser radar

The multiple phase screens and Fourier-transform algorithm for numerical simulation of beam propagation through atmospheric turbulence is important for imaging problems, lidar or laser radar. In this work Fast-Fourier-transform-based model of phase screens are used to simulate the propagation of a radar beam. The refractive-index power spectrum used for phase screen generation is the so-called modified atmospheric spectrum defined by L C Andrews. The standard compensations used to correct the undersampling at low spatial frequencies are improved, and the limitations and numerical requirements for a simulation of given accuracy are established. By using the improved algorithm, the scintillation index of gaussian beams propagation through atmospheric turbulence is studied. Comparisons of simulations with analytic results are presented. The on-axis theoretical scintillation index is compared with simulated results at different ranges and good agreement is shown between numerical simulation and theoretical results.