Echo characteristics of laser beams reflected from rough targets with a finite size in atmospheric turbulence

Abstract

Based on the extended Huygens-Fresnel principle, echo characteristics of the plane and spherical waves reflected from a rough target with a finite size in atmospheric turbulence were studied. The expressions of the intensity variance, covariance functions and scintillation index of the plane and spherical waves reflected from a rough target in double-path propagation through atmospheric turbulence were proposed considering the turbulence perturbations. The expressions were numerically calculated, and the results show that the intensity fluctuation caused by turbulence decreases with increasing target size. It is also found that under weak turbulence, it is mainly the log-amplitude fluctuations that affect the second-order statistical properties of the received beam intensity. Results obtained can potentially provide theoretical and technical guidance for the future applications of laser target detection and target recognition in space.