大气对532nm激光影响在漫反射激光测距中的应用

Study of Atmospheric Effects on a 532nm Laser and Its Applications in the Laser Ranging Based on Diffuse Reflection

激光光束在大气中的传输是与大气特征有关的,如大气湍流、大气散射与吸收,而且激光测距的回波除了与距离有关外,其回波数及精度也与大气特征相关。漫反射激光测距的目标是低轨空间碎片,在一定反射截面的条件下,应用一定功率的激光进行地面靶板漫反射测距试验,以确定多少功率的激光器可实现空间碎片的漫反射测距,这时地面靶的距离选取应该具有代表性,它代表了在一定斜程下穿过整个大气层的效应。通过对大气湍流和大气衰减对激光传输的影响进行分析,理论上计算出在低轨目标为400km时,漫反射激光测距试验地面靶的水平距离该取多远时才能代表在一定斜程下穿过400km大气层的效应,从而为漫反射激光测距试验地面靶距离的选取提供参考依据。

In tests of laser ranging based on diffuse reflection of ground targets, the selection of distances to targets must take into account influences from the atmosphere. This is because only tests based on considerations of atmospheric influences can adequately reflect the reality encountered in future applications of laser ranging based on diffuse reflection. Since the purpose is to detect low-orbit space debris, these tests use ground targets to determine the effective ranges of laser ranging for a given target cross section at a given laser power. Among the relevant settings for such tests are target locations, which need to be at different heights along the direction of laser-beam propagation to represent different levels of laser-beam transmission within the amosphere. This paper describes the effects of atmospheric turbulence and atmospheric attenuation on laser transmission by focusing on the generating mechanisms of these effects. We list theoretical calculations at different elevation angles and different laser transmission distances, and yield the relations of these effects to the levels of transmission. Finally we determine the practical parameters for a test of laser ranging based on diffuse reflection.