Research On Multiple Scattering And Modeling Of Laser In Complex Atmosphere Environment

The main research content of this paper is the transmission characteristics of laser in complex environment.Laser transmission in the atmosphere will inevitably be affected by aerosols,especially in fog and sand environments.Water droplets and sand particles scatter and absorb the laser,which affects the intensity of laser transmission and the accuracy of radar detection.Therefore,it is of great significance to study the laser transmission in complex environments.First,the composition of aerosol particles,physical properties of mist and dust particles,including size parameters,refractive index,etc.are introduced.The relationship between various parameters of aerosol was discussed in detail.It is found that fog type,water content,size distribution,and dielectric constant corresponding to different wavelengths are important parameters that affect fog visibility.Sand and dust areas,electrical properties,water content,and height are important parameters that affect the visibility of the sand and dust environment.Based on the radiation transmission theory,the scattering characteristics of different laser incidents in the fog environment were analyzed using Mie theory.The scattering coefficients of laser in fog are calculated: asymmetry factor,albedo,attenuation coefficient,extinction coefficient,etc.Considering the low visibility environment,the Monte Carlo method is more accurate,and the attenuation and scattering characteristics of the laser incident into the low visibility fog are analyzed.On this basis,a new laser forward attenuation model and backward attenuation model in low visibility fog are established.Comparing most of the existing forward attenuation models,it is found that in low visibility environments,the results of Monte Carlo calculation are more accurate.The backward attenuation fitting parameters of the new model were tested,and a more accurate fitting result was obtained.Finally,the transmission characteristics of laser in sand and dust are considered,the four-flux method is introduced,the single and multiple scattering characteristics of laser in sand and dust environment are calculated,and different attenuation models are compared.