Study Of Laser Propagation And Attenuation Through The Rain And Fog Environment

Laser reaching the process of receiving equipment via the atmospheric transmission, theability to penetrate the atmosphere is weak, it can be scattered and absorbed by atmosphericmolecules, aerosol, dust and others,which results in the attenuation of laser signals and thereducing of detecting ability, the laser energy that reaches the receiving device is reduced,affect the performance of laser communication, therefore, the study of laser transmissioncharacteristics in complex atmospheric environment has important significance. This papermainly studies the scattering of laser signals and attenuation characteristics in rainfall and fogenvironment.In this paper, the physical properties of rainfall and fog is introduced a more detailedelaboration, micron wavelength laser propagation in the atmosphere, the main theory is Miescattering theory, simulates and analyzes attenuation factor efficiency’s variation features withthe change of scattering particle size, at the same time, analyzes of the spatial distributionparticle scattering light intensity. Based on rain and fog characteristics and the Mie scatteringtheory:1) is deduced the theoretical calculation of the attenuation of raindrop size distributionmode in rainfall environment,combining empirical model, by Matlab simulates and analyzesrain attenuation coefficient of M-P, Joss and two empirical model with the change of rainfallrate, it is concluded that the laser transmission attenuation is more serious in light rain than theheavy rain;2) based on a single property of the droplets, gives common experience model ofcausing laser attenuation in fog environment,by Matlab simulates and analyzes attenuationcharacteristics between different models of the advection fog and radiation fog, it is concludedthat the the laser wavelength is longer, the attenuation coefficient is smaller, when visibility ismore than500metres, each model attenuation were similar, but the visibility is less than500meters, the difference between them with the decrease of visibility is more and more big,multiple scattering is considered. This paper also discussed laser attenuation when the laser transmission in the fog by oblique cheng,by the simulation analysis it is concluded that theenergy attenuation and transport highly linear change.