Phase screen modeling method for discrete raindrop media based on spectral inversion method
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A phase screen and spectral inversion technology, applied in measurement devices, instruments, scientific instruments, etc., can solve the problems of incomplete description of light field information, not in line with virtual experiments, not considering the phase disturbance of raindrops, etc.
Active Publication Date: 2017-05-10
HARBIN INST OF TECH
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[0005] The purpose of the present invention is to solve the problem that the phase screen model of the existing discrete raindrop medium does not fully describe the light field information, does not meet the requirements of the virtual experiment, and does not consider the phase disturbance of the raindrop to the light field, and proposes a method based on The phase screen modeling method of the discrete raindrop medium by the spectral inversion method includes the following steps:
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specific Embodiment approach 1
[0032] Embodiment one: the phase screen modeling method of the discrete raindrop medium based on the spectrum inversion method of the present embodiment includes the following steps:
[0033] Step 1: Get the raindrop particle at position r relative to the position R j Scattering potential energy V(r) of raindrop particles;
[0034] Step 2: Use Fourier transform to express the scattering potential energy V(r) of raindrop particles, and obtain the scattering potential energy V after Fourier transform 0 (r);
[0035] Step 3: Through the Fourier transformed scattering potential energy V 0 (r) and the scattering amplitude function f of a single scattering particle 0 (K), combined with the Born approximation method, we get:
[0036]
[0037] where f 0 (K) represents the spatial frequency spectrum of the scattering amplitude of a plane wave passing through a particle with a radius of a, is the approximate value of the scattering potential energy;
[0038] Step 4: Express t...
specific Embodiment approach 2
[0053] Specific implementation mode two: the difference between this implementation mode and specific implementation mode one is: f 0 (K) specifically:
[0054]
[0055] where k is the wave number, J 1 Represents a first-order Bessel function.
[0056] Other steps and parameters are the same as those in Embodiment 1.
specific Embodiment approach 3
[0057] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that in step two, the scattering potential energy V after the Fourier transform is 0 (r) specifically:
[0058]
[0059] Other steps and parameters are the same as those in Embodiment 1 or Embodiment 2.
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Abstract
The invention relates to a phase screen modeling method for discrete raindrop media based on a spectral inversion method, and belongs to discrete raindrop medium phase screen modeling field. In order to overcome the shortcomings that the description of light field information is incomplete in a phase screen model of discrete raindrop media, the requirements of a virtual test is not satisfied, and the phase disturbance of raindrops to the light field is not considered, the invention proposes a phase screen modeling method for discrete raindrop media based on the spectral inversion method, the phase screen modeling method including the steps of obtaining scattering potential energy of raindrop particles; obtaining the scattering potential energy after Fourier transform; obtaining an approximate value of the scattering potential energy through the scattering potential energy after Fourier transform; expressing a second-order correlation moment three-dimensional power spectral function of a dielectric constant of the raindrop particles by a formula; expressing a dielectric constant power spectrum of the raindrops by a formula; expressing a second-order correlation moment power spectrum of a medium refractive index of the raindrops by a formula; and obtaining a phase screen model of mixed media on a transmission path according to the spectral inversion method. The invention is applicable to a simulation model of laser transmission in rain.
Description
technical field [0001] The invention relates to a phase screen modeling method of a discrete raindrop medium based on a spectrum inversion method, and belongs to the field of phase screen modeling of a discrete raindrop medium. Background technique [0002] Due to the change of the dielectric constant of the atmospheric medium, the light wave front of the laser beam transmitted in the atmosphere will be affected by random phase disturbance. These phase disturbances are mainly caused by turbulent and turbid media, and the scattering of individual particles is also accompanied by a certain degree of attenuation. Therefore, in the virtual experiment, for the atmospheric space constructed by the low-scattering medium, the laser transmission model needs to give all the information of the light field including the amplitude and phase of the target plane. In the medium with low scattering properties, rain is the most important atmospheric medium that causes laser power attenuation...
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