Model of a burst imaging lidar through the atmosphere

ABSTRACT This paper presents a model used to predict the performances of a burst illumination imaging lidar propagating through theatmosphere. The laser beam propagates near the ground on a long distance and undergoes strong perturbations due toatmospheric turbulences. This model takes into account both propagating paths: forward propagation as the wavefrontprogresses towards the observed object and backward propagation as the light is reflected back to the receiver.Keywords : active imaging system, gated camera, turbulence speckle pattern 1. INTRODUCTION The burst illumination laser imaging technique5 can be summarized as follows: a pulsed laser delivers high power peak andinstantaneously illuminates a slice of space. A gated camera views this slice of space with adequate time synchronization.The main advantages of this technique, compared to passive imagery, are the atmospheric scattering rejection in adverseweather conditions (fog, rain . . .), the small dependence on the environment radiance variations (active system), goodangular resolution due to short wavelength and no need of a scanning device.Such devices can be used for long range target observation. As it implies long path propagation of the laser beam throughthe atmosphere, the wavefront is disturbed by atmospheric scattering and turbulence effects. The purpose of this paper is toaddress only the latter effect on this type of laser imagery.