Tilt path atmospheric turbulence phase screen generation and light field transmission simulation method

Abstract

The invention discloses a slant path atmospheric turbulence phase screen generation and light field transmission simulation method. Belongs to the technical field of satellite-ground laser communication. The method comprises the following steps: firstly, establishing a three-layer height spectrum model in a slant-range atmospheric turbulence environment, then generating an initial field suitable for vacuum and turbulence environments by using an angular spectrum method, and generating n corresponding random dynamic phase screens according to atmospheric turbulence characteristics of different heights on a slant-range path and distribution characteristics of atmospheric wind speed. Superposing the initial field and the first phase screen, performing two-dimensional Fourier transform, and performing inverse Fourier transform on the transform field by using an angular spectrum method to obtain field distribution in front of the next phase screen; and repeating the process to pass through n phase screens in sequence, and finally obtaining the output field distribution of the uplink and the downlink. The method can effectively simulate the effects of refractive index fluctuation, wavefront distortion, light intensity flicker and the like caused by oblique-range atmospheric turbulence, and provides important theoretical support and application value for researching oblique-range laser transmission characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite-to-ground laser communications, and in particular relates to a method for generating an atmospheric turbulence phase screen and simulating light field transmission on a slant path. Background Art

[0002] With the deepening of free-space optical communication research, researchers have not only extensively studied horizontal links but also slant links. Slant links generally refer to space-to-ground laser communications. Unlike horizontal links, the atmospheric refractive index parameters of slant links vary with factors such as altitude, wind speed, and humidity. Furthermore, communications between space stations and ground stations, and between ground stations using satellite relays, involve slant transmission of laser beams because one party is in motion. Compared to vertical and horizontal laser communications, slant transmission atmospheric laser communications are more common.

[0003] However, atmospheric turbulence is a significant factor affecting laser communications. It can cause fluctuations in the refractive index, which in turn leads to random variations in the amplitude and phase of the light wave. This can lead to phenomena such as light intensity flickering, wavefront distortion, arrival angle fluctuations, and beam drift, severely impacting the transmission performance of space optical communications. Therefore, building on the theoretical foundation of research on the optical transmission characteristics of unidirectional links, the current mainstream research approach is to investigate the bidirectional optical transmission characteristics of slant-path links.

[0004] Researchers have continuously deepened their understanding of atmospheric turbulence and discovered that actual atmospheric turbulence is non-uniform and anisotropic, with its power spectrum function varying with factors such as altitude. To this end, some researchers have proposed non-Kolmogorov turbulence models, which can describe various types of non-uniform turbulence. In the paper "Numerical Simulation of a Three-Layer Transmission Model for Earth-Satellite Atmospheric Turbulence Paths," Shen Lingjun et al. from Shanghai University proposed a three-layer Earth-Satellite transmission simulation model, using three layers of phase screens to build a satellite-to-ground laser transmission system. In the paper "Satellite-to-ground Optical Downlink Model Using Mode Mismatching Multi-mode Photonic Lanterns," Guo et al. used 20 layers of von-Karman atmospheric turbulence phase screens to simulate satellite-to-ground atmospheric turbulence effects within a 0-20 km radius. However, the statistical characteristics of atmospheric turbulence and the distribution of atmospheric wind speeds vary at different altitudes along the slant path. Traditional slant-path laser atmospheric turbulence modeling and simulation methods cannot accurately represent the evolution of real atmospheric turbulence. Summary of the Invention

[0005] (1) Technical problems solved

[0006] In view of the shortcomings of the existing technology, the present invention provides a method for generating an atmospheric turbulence phase screen and simulating light field transmission in an oblique path, which solves the problems raised in the above-mentioned background technology.

[0007] (2) Technical solution

[0008] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0009] A method for generating an atmospheric turbulence phase screen and simulating light field transmission in a slant path, comprising the following steps:

[0010] S1: Establish a three-layer height spectrum model for the power spectrum index of atmospheric turbulence at different altitudes in the slant path;

[0011] S2: Generate initial fields suitable for vacuum and turbulent environments using the angular spectrum method;

[0012] S3: Generate n corresponding dynamic random phase screens according to the atmospheric turbulence characteristics at different heights on the slant path and the distribution characteristics of atmospheric wind speed;

[0013] S4: The initial field is superimposed on the first phase screen and then a two-dimensional Fourier transform is performed. Then, the transformed field is inversely Fourier transformed using the angular spectrum method to obtain the field distribution before the next phase screen.

[0014] S5: Repeat the S4 process to make the initial field pass through n dynamic random phase screens in sequence, and finally obtain the output field distribution of the uplink and downlink, thereby effectively simulating the refractive index fluctuations, wavefront distortion and light intensity scintillation effects caused by slant atmospheric turbulence.

[0015] Furthermore, a three-layer height spectrum model is established in S1, which is divided into three relatively stable layers in the vertical direction: boundary layer, troposphere, and stratosphere;

[0016] The boundary layer refers to the atmospheric layer with an altitude of 1 to 2 km, the troposphere refers to the atmospheric layer with an altitude of 8 to 10 km, and the stratosphere refers to the atmospheric layer above 10 km. For the three-layer altitude spectrum, the specific expression is as follows:

[0017]

[0018] Where: Φ n (κ,α,h) is the three-dimensional spatial power spectral density; κ is the spatial frequency; is the spatial wave number, where λ is the wavelength of the light wave; α is the turbulence spectrum index that varies with altitude h; h is the altitude above the ground; L = Hsec(ζ) is the total transmission distance, where H is the total altitude and ζ is the zenith angle;

[0019] Turbulence spectral index α(h) and atmospheric refractive index structure constant Determined by the following expression:

[0020]

[0021] Where: α1, α2 and α3 are the turbulence spectrum indices in the boundary layer, troposphere and stratosphere respectively; H1 and H2 are the atmospheric boundaries; b1 and b2 are the interlayer smoothing coefficients; w (m / s) is the root mean square wind speed; A0 (m -23 ) is the ground refractive index structure parameter.

[0022] Furthermore, the angular spectrum method in S2 refers to the spatial spectrum of the light field distribution, which converts the spatial domain problem into the spectrum domain through Fourier transform, and then calculates the propagation of the light field through the propagation operator;

[0023] The propagation of the light field U(x,y,z) can be described by its angular spectrum A(f x ,f y ,z) to describe, where f x and f y is the spatial frequency, and the angular spectrum of the light field is obtained by the two-dimensional Fourier transform of the light field:

[0024] A(f x ,f y ,z)=FFT{U(x,y,0)}

[0025] Where: A(f x ,f y ,z) is the angular spectrum at z = 0; U(x,y,0) is the light field at z = 0; the operator FFT represents fast Fourier transform.

[0026] Furthermore, since the atmospheric turbulence intensity of the oblique bidirectional optical transmission path S3 has a distinct layered structure and varies dramatically with altitude, in order to fully sample the regions with different refractive index fluctuations, the value of n will be determined using the equal Rytov variance interval phase screen method. Based on the integral effect of the refractive index fluctuations of the random medium, it is assumed that the integral effect caused by the turbulent atmosphere between adjacent phase screens is equal.

[0027] The specific expression is as follows:

[0028]

[0029] Where Δz j is the distance between the phase screens from step j to step j+1; The spacing is Δz j Rytov variance; c is a constant.

[0030] Furthermore, the output field distribution of the uplink and downlink is finally obtained in S5, and the specific expression is as follows:

[0031]

[0032] Where n is the number of steps of light field distribution propagation; the operator represents angular spectrum diffraction propagation; E(x1,y1) is the initial field; E(x,y,z) is the output field; is the scaling factor from step j to step j+1 in the light propagation process; xj and yj are the propagation grids in step j; z j is the j-th propagation distance, j=1,2,3···n; S(x j ,y j ) is the introduced super-Gaussian filter function; is the random complex phase disturbance of the j-th step turbulence, which is the random phase screen.

[0033] Furthermore, the slant propagation path is divided into n segments using the equal Rytov variance interval phase screen method. The simulation assumes that the atmospheric refractive index structure constant of each segment is uniform, and the atmospheric refractive index structure constant of each segment can be obtained. The specific method is: take the path average value of the turbulent atmospheric refractive index structure constant between two phase screens;

[0034]

[0035] Where Δz j is the distance between the phase screens from step j to step j+1; The spacing is Δz j The path average of z j is the propagation distance of the jth step.

[0036] Further, is the random complex phase disturbance of the j-th step turbulence, that is, the random phase screen. However, the actual atmospheric turbulence has the characteristics of dynamic evolution over time, and the static phase screen model is difficult to accurately reflect this real dynamic change process. Taking into account the altitude distribution characteristics of the oblique atmospheric turbulence and the distribution characteristics of the atmospheric wind speed, the Non-Kolmogorov turbulence model and Taylor turbulence freezing theory are used to construct the dynamic atmospheric turbulence phase screen of the oblique link.

[0037] Furthermore, in the dynamic turbulence simulation process, the phase screen is first generated by the power spectrum inversion method with subharmonic compensation, and then the rotation interception phase screen method is used to finally obtain a small phase screen with correlation.

[0038] Non-Kolmogorov turbulence model with random phase screen in time domain In the form of:

[0039]

[0040] Where C is an N×N complex random matrix with a mean of 0 and a variance of 1; N and x are the number of sampling points of the numerical simulation respectively;

[0041] When performing numerical simulations, the formula needs to be written in the form of Fourier series Φ(jx,ly):

[0042]

[0043] Where, is the wave number increment;

[0044] Fourier series for low-frequency harmonic compensation Expressed as:

[0045]

[0046] Where p is the subharmonic order and the subharmonic frequency interval is k xp =k x / 3 p , k yp =k y / 3 p ;

[0047] The final phase Φ(x,y) expression of the phase screen is:

[0048]

[0049] Taylor's turbulence freezing theory holds that actual atmospheric turbulence exhibits dynamic characteristics in both time and space, but within a relatively short characteristic time, its spatial structure can be approximately regarded as a "frozen" state. At this time, the spatial distribution characteristics of turbulence remain stable, that is, the spatial characteristics of turbulence at a certain point in space remain unchanged, while the temporal characteristics vary with wind speed. The formula is as follows:

[0050]

[0051] Where, is the wavefront phase; t is the time variable; v h is the lateral wind speed; t d is the characteristic time;

[0052] The temporal characteristics of dynamic turbulence are generally measured using the Greenwood frequency as an indicator, which is related to wind speed and atmospheric coherence length parameters. The simple calculation formula is:

[0053]

[0054] Where, f Gis the Greenwood frequency; v is the wind speed; r0 is the atmospheric coherence length.

[0055] (3) Beneficial effects

[0056] Compared with the prior art, the present invention provides a method for generating an atmospheric turbulence phase screen and simulating light field transmission along an oblique path, which has the following beneficial effects:

[0057] The present invention simulates a space laser communication system with bidirectional optical transmission by establishing a three-layer height spectrum model of bidirectional optical transmission in an slant-range link. According to the statistical characteristics of atmospheric turbulence at different altitudes of the slant-range link, dynamic phase screens of atmospheric turbulence at multiple altitudes are generated. Through the multi-layer phase screens, the output field distribution of the uplink and downlink links is finally generated, thereby realizing the simulation of effects such as refractive index fluctuations and wavefront phase distortion caused by atmospheric turbulence. Compared with the traditional slant-range atmospheric turbulence simulation system, the present invention can effectively characterize the statistical characteristics of atmospheric turbulence at different altitudes and the distribution characteristics of atmospheric wind speed, and conforms to the laws of real atmospheric turbulence evolution, which can provide a technical reference for the field of slant-range laser communication channel simulation in the new generation of information technology industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a block diagram of the overall structure provided by an embodiment of the present invention;

[0059] Figure 2 Schematic diagram of a three-layer height spectrum model provided by an embodiment of the present invention;

[0060] Figure 3 This is a schematic diagram of an oblique path divided into n segments provided by an embodiment of the present invention;

[0061] Figure 4 1 is a schematic diagram of a dynamic turbulence phase screen simulation provided by an embodiment of the present invention;

[0062] Figure 5 This is a system simulation model diagram of bidirectional optical transmission provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0064] Example

[0065] like Figure 1As shown, an embodiment of the present invention provides a method for generating an atmospheric turbulence phase screen and simulating light field transmission along an oblique path, comprising the following steps:

[0066] S1: Establish a three-layer height spectrum model for the power spectrum index of atmospheric turbulence at different altitudes in the slant path;

[0067] Specifically, a schematic diagram of a three-layer height spectrum model proposed in one embodiment of the present invention is shown as follows: Figure 2 As shown. Three relatively stable layers are roughly divided in the vertical direction: boundary layer, troposphere, and stratosphere. The boundary layer refers to the atmospheric layer with an altitude of 1 to 2 km, the troposphere refers to the atmospheric layer with an altitude of 8 to 10 km, and the stratosphere refers to the atmospheric layer above 10 km. For the three-layer altitude spectrum, the specific expression is as follows:

[0068]

[0069] Where: Φ n (κ,α,h) is the three-dimensional spatial power spectral density; κ is the spatial frequency; is the spatial wave number, where λ is the wavelength of the light wave; α is the turbulence spectrum index that varies with altitude h; h is the altitude above the ground; L = Hsec(ζ) is the total transmission distance, where H is the total altitude and ζ is the zenith angle;

[0070] Turbulence spectral index α(h) and atmospheric refractive index structure constant Determined by the following expression:

[0071]

[0072] Where: α1, α2 and α3 are the turbulence spectrum indices in the boundary layer, troposphere and stratosphere respectively; H1 and H2 are the atmospheric boundaries; b1 and b2 are the interlayer smoothing coefficients; w (m / s) is the root mean square wind speed; A0 (m -23 ) is the ground refractive index structure parameter.

[0073] S2: Generate initial fields suitable for vacuum and turbulent environments using the angular spectrum method.

[0074] Among them, the angular spectrum method refers to the spatial spectrum of the light field distribution. The spatial domain problem is converted to the spectrum domain through Fourier transform, and then the propagation of the light field is calculated through the propagation operator.

[0075] Specifically, the propagation of the light field U(x,y,z) can be expressed as x ,f y ,z) to describe, where f x and f y is the spatial frequency, and the angular spectrum of the light field is obtained by the two-dimensional Fourier transform of the light field:

[0076] A(f x ,f y ,z)=FFT{U(x,y,0)}

[0077] Where: A(f x ,f y ,z) is the angular spectrum at z = 0; U(x,y,0) is the light field at z = 0; the operator FFT represents fast Fourier transform.

[0078] S3: Generate n corresponding dynamic random phase screens according to the atmospheric turbulence characteristics at different heights on the slant path and the distribution characteristics of atmospheric wind speed.

[0079] Specifically, an embodiment of the present invention proposes a schematic diagram of dividing the oblique path into n segments, such as Figure 3 As shown. The equal Rytov variance interval phase screen method is used. Based on the integral effect of the refractive index fluctuation of the random medium, it is assumed that the integral effect caused by the turbulent atmosphere between adjacent phase screens is equal. The specific expression is as follows:

[0080]

[0081] Where Δz j is the distance between the phase screens from step j to step j+1; The spacing is Δz j Rytov variance; c is a constant.

[0082] S4: The initial field is superimposed on the first phase screen and then a two-dimensional Fourier transform is performed; then the transformed field is inverse Fourier transformed using the angular spectrum method to obtain the field distribution before the next phase screen.

[0083] S5: Repeat the above four steps to pass through n phase screens in sequence, and finally obtain the output field distribution of the uplink and downlink. The specific expression is as follows:

[0084]

[0085] Where n is the number of steps of light field distribution propagation; the operator represents angular spectrum diffraction propagation; E(x1,y1) is the initial field; E(x,y,z) is the output field; is the scaling factor from step j to step j+1 in the light propagation process; xj and yj are the propagation grids in step j; z j is the j-th propagation distance, j=1,2,3···n; S(x j ,y j ) is the introduced super-Gaussian filter function; is the random complex phase disturbance of the j-th step turbulence, which is the random phase screen.

[0086] like Figure 4 As shown, a schematic diagram of a dynamic turbulence phase screen simulation of an oblique path atmospheric turbulence phase screen generation and light field transmission simulation method proposed by an embodiment of the present invention is shown. Since actual atmospheric turbulence has the characteristic of dynamic evolution over time, it is difficult for a static phase screen model to accurately reflect this real dynamic change process. Taking into account the altitude distribution characteristics of oblique path atmospheric turbulence and the distribution characteristics of atmospheric wind speed, the Non-Kolmogorov turbulence model and Taylor turbulence freezing theory are used to construct a dynamic atmospheric turbulence phase screen for an oblique path link. In the dynamic turbulence simulation process, the phase screen is first generated by the power spectrum inversion method of subharmonic compensation, and then the rotation interception phase screen method is used to finally obtain a small phase screen with correlation.

[0087] Non-Kolmogorov turbulence model with random phase screen in time domain In the form of:

[0088]

[0089] Where C is an N×N complex random matrix with a mean of 0 and a variance of 1; N and x are the number of sampling points of the numerical simulation respectively;

[0090] When performing numerical simulations, the formula needs to be written in the form of Fourier series Φ(jx,ly):

[0091]

[0092] Where, is the wave number increment;

[0093] Fourier series for low-frequency harmonic compensation Expressed as:

[0094]

[0095] Where p is the subharmonic order and the subharmonic frequency interval is k xp =k x / 3 p , k yp =k y / 3 p ;

[0096] The final phase Φ(x,y) expression of the phase screen is:

[0097]

[0098] Taylor's turbulence freezing theory states that actual atmospheric turbulence exhibits dynamic characteristics in both time and space, but within a relatively short characteristic timeframe, its spatial structure can be approximated as being in a "frozen" state. During this period, the spatial distribution of turbulence remains stable, meaning that the spatial characteristics of turbulence at a given point in space remain unchanged, while its temporal characteristics vary with wind speed. The formula is as follows:

[0099]

[0100] Where, is the wavefront phase; t is the time variable; v h is the lateral wind speed; t d is the characteristic time;

[0101] The temporal characteristics of dynamic turbulence are generally measured using the Greenwood frequency as an indicator, which is related to wind speed and atmospheric coherence length parameters. The simple calculation formula is:

[0102]

[0103] Where, f G is the Greenwood frequency; v is the wind speed; r0 is the atmospheric coherence length.

[0104] like Figure 5 As shown, a system simulation model diagram of bidirectional optical transmission of a slant path atmospheric turbulence phase screen generation and light field transmission simulation method proposed by an embodiment of the present invention, the initial field is bidirectionally transmitted through multiple layers of dynamic random phase screens in the slant path link.

[0105] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for generating an atmospheric turbulence phase screen and simulating light field transmission in a slant path, characterized in that the steps include: S1: Establish a three-layer height spectrum model for the power spectrum index of atmospheric turbulence at different altitudes in the slant path; S2: Generate initial fields suitable for vacuum and turbulent environments using the angular spectrum method; S3: Generate n corresponding dynamic random phase screens according to the atmospheric turbulence characteristics at different heights on the slant path and the distribution characteristics of atmospheric wind speed; S4: The initial field is superimposed on the first phase screen and then a two-dimensional Fourier transform is performed. Then, the transformed field is inversely Fourier transformed using the angular spectrum method to obtain the field distribution before the next phase screen. S5: Repeat the S4 process to make the initial field pass through n dynamic random phase screens in sequence, and finally obtain the output field distribution of the uplink and downlink, thereby effectively simulating the refractive index fluctuations, wavefront distortion and light intensity scintillation effects caused by slant atmospheric turbulence.

2. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 1, characterized in that: In the S1, a three-layer height spectrum model is established, which is divided into three relatively stable layers in the vertical direction: boundary layer, troposphere, and stratosphere; The boundary layer refers to the atmospheric layer with an altitude of 1 to 2 km, the troposphere refers to the atmospheric layer with an altitude of 8 to 10 km, and the stratosphere refers to the atmospheric layer above 10 km. For the three-layer altitude spectrum, the specific expression is as follows: Where: Φ n (κ,α,h) is the three-dimensional power spectrum density; κ is the spatial frequency; is the spatial wave number, where λ is the wavelength of the light wave; α is the turbulence spectrum index that varies with altitude h; h is the altitude above the ground; L = Hsec(ζ) is the total transmission distance, where H is the total altitude and ζ is the zenith angle; Turbulence spectral index α(h) and atmospheric refractive index structure constant Determined by the following expression: Where: α1, α2 and α3 are the turbulence spectrum indices in the boundary layer, troposphere and stratosphere respectively; H1 and H2 are the atmospheric boundaries; b1 and b2 are the interlayer smoothing coefficients; w (m / s) is the root mean square wind speed; A0 (m -23 ) is the ground refractive index structure parameter.

3. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 1, characterized in that: The angular spectrum method in S2 refers to the spatial spectrum of the light field distribution. The problem in the spatial domain is converted to the spectral domain through Fourier transform, and then the propagation of the light field is calculated through the propagation operator. Specifically, the propagation of the light field U(x,y,z) can be expressed as x ,f y ,z) to describe, where f x and f y is the spatial frequency, and the angular spectrum of the light field is obtained by the two-dimensional Fourier transform of the light field: A(f x ,f y ,z)=FFT{U(x,y,0)} Where: A(f x ,f y ,z) is the angular spectrum at z = 0; U(x,y,0) is the light field at z = 0; the operator FFT represents fast Fourier transform.

4. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 1, characterized in that: Because the atmospheric turbulence intensity of the oblique bidirectional optical transmission path has a distinct layered structure and varies dramatically with altitude, in order to fully sample the regions with different refractive index fluctuations, the value of n will be determined using the equal Rytov variance interval phase screen method. Based on the integral effect of the refractive index fluctuations of the random medium, it is assumed that the integral effect caused by the turbulent atmosphere between adjacent phase screens is equal. The specific expression is as follows: Where Δz j is the distance between the phase screens from step j to step j+1; The spacing is Δz j Rytov variance; c is a constant.

5. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 1, characterized in that: The output field distribution of uplink and downlink is finally obtained in S5, and the specific expression is as follows: Where n is the number of steps of light field distribution propagation; the operator represents angular spectrum diffraction propagation; E(x1,y1) is the initial field; E(x,y,z) is the output field; is the scaling factor from step j to step j+1 in the light propagation process; xj and yj are the propagation grids in step j; z j is the j-th propagation distance, j=1,2,3···n; S(x j ,y j ) is the introduced super-Gaussian filter function; is the random complex phase disturbance of the j-th step turbulence, which is the random phase screen.

6. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 4, characterized in that: The slant propagation path is divided into n segments using the equal Rytov variance interval phase screen method. The simulation assumes that the atmospheric refractive index structure constant of each segment is uniform. The atmospheric refractive index structure constant of each segment can be obtained by taking the path average value of the turbulent atmospheric refractive index structure constant between two phase screens. Where Δz j is the distance between the phase screens from step j to step j+1; The spacing is Δz j The path average of z j is the propagation distance of the jth step.

7. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 5, characterized in that: is the random complex phase disturbance of the j-th step turbulence, that is, the random phase screen. However, the actual atmospheric turbulence has the characteristics of dynamic evolution over time, and the static phase screen model is difficult to accurately reflect this real dynamic change process. Taking into account the altitude distribution characteristics of the oblique atmospheric turbulence and the distribution characteristics of the atmospheric wind speed, the Non-Kolmogorov turbulence model and Taylor turbulence freezing theory are used to construct the dynamic atmospheric turbulence phase screen of the oblique link.

8. The method for generating an atmospheric turbulence phase screen and simulating light field transmission along a slant path according to claim 7, characterized in that: In the dynamic turbulence simulation process, the phase screen is first generated by the power spectrum inversion method of subharmonic compensation, and then the rotation interception phase screen method is used to finally obtain a small phase screen with correlation. Non-Kolmogorov turbulence model with random phase screen in time domain In the form of: Where C is an N×N complex random matrix with a mean of 0 and a variance of 1; N and x are the number of sampling points of the numerical simulation respectively; When performing numerical simulations, the formula needs to be written in the form of Fourier series Φ(jx,ly): Where, is the wave number increment; Fourier series for low-frequency harmonic compensation Expressed as: Where p is the subharmonic order and the subharmonic frequency interval is k xp =k x / 3 p , k yp =k y / 3 p ; The final phase Φ(x,y) expression of the phase screen is: Taylor's turbulence freezing theory holds that actual atmospheric turbulence exhibits dynamic characteristics in both time and space, but within a relatively short characteristic time, its spatial structure can be approximately regarded as a "frozen" state. At this time, the spatial distribution characteristics of turbulence remain stable, that is, the spatial characteristics of turbulence at a certain point in space remain unchanged, while the temporal characteristics vary with wind speed. The formula is as follows: Where, is the wavefront phase; t is the time variable; v h is the lateral wind speed; t d is the characteristic time; The temporal characteristics of dynamic turbulence are generally measured using the Greenwood frequency as an indicator, which is related to wind speed and atmospheric coherence length parameters. The simple calculation formula is: Where, f G is the Greenwood frequency; v is the wind speed; r0 is the atmospheric coherence length.

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