Offshore non-uniform electromagnetic wave propagation loss detection method
By collecting meteorological and hydrological data through buoy platforms deployed at sea, and combining a three-dimensional variational assimilation algorithm and an ocean-air-wave coupling model, electromagnetic wave propagation loss was calculated. This solved the problem of accuracy in electromagnetic wave propagation loss under non-uniform evaporation waveguide environments, achieving precise electromagnetic wave loss detection and improving the performance of maritime communication and radar.
Patent Information
- Application Number
- CN202511518043.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-02-17
AI Technical Summary
Existing technologies struggle to accurately characterize the propagation loss of electromagnetic waves at sea in non-uniform evaporation waveguide environments, leading to significant prediction errors and impacting the performance optimization of communication, navigation, and marine monitoring systems.
Multiple buoy platforms were used to collect meteorological and hydrological data. Combined with a three-dimensional variational assimilation algorithm and an ocean-atmosphere-wave coupling model, electromagnetic wave propagation loss was calculated using parabolic equations and split-step Fourier algorithms to accurately simulate a non-uniform evaporation waveguide environment.
It enables accurate detection of the propagation loss of non-uniform electromagnetic waves at sea, accurately reflects the non-uniformity of the ocean atmosphere, and improves the stability of communication links and radar detection performance.
Smart Images
Figure CN121543320A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of marine electromagnetic environment detection, and particularly relates to a method for detecting offshore non-uniform electromagnetic wave propagation loss. BACKGROUND
[0002] At present, electromagnetic wave propagation technology has been widely applied in electronic navigation, weather prediction, radar monitoring, satellite communication and marine remote sensing and other fields, and plays an important role in supporting offshore information acquisition and transmission system. Accurate characterization of electromagnetic wave propagation loss is of great significance to improve the stability of offshore communication link, optimize radar detection performance and ensure navigation safety.
[0003] Existing researches usually lay out single-point observation devices to obtain meteorological and hydrological parameters such as temperature, relative humidity, atmospheric pressure, and combine simulation or empirical models to construct regional uniform electromagnetic propagation loss under the condition of evaporation waveguide. This method can provide certain basis for electromagnetic wave propagation loss analysis in theory, but since it assumes that the atmospheric structure remains uniform in space, it is difficult to fully reflect the electromagnetic wave propagation loss under the condition of real non-uniform evaporation waveguide.
[0004] In fact, the offshore electromagnetic environment is affected by wind speed, temperature, relative humidity, atmospheric pressure and other factors, and shows significant spatio-temporal non-uniformity. This non-uniform structure will lead to complex changes in electromagnetic wave propagation loss characteristics, so that the model based on the uniform assumption has large deviation when predicting the propagation loss. Therefore, it is urgent to establish a high-precision electromagnetic wave propagation loss measurement method under the condition of non-uniform evaporation waveguide, so as to more accurately simulate and predict the offshore electromagnetic wave propagation characteristics, and provide scientific support for the performance optimization of communication, navigation and marine monitoring systems. SUMMARY
[0005] To solve the above technical problems, the present application provides a method for detecting offshore non-uniform electromagnetic wave propagation loss, so as to accurately detect offshore non-uniform electromagnetic wave propagation loss and truly reflect the non-uniformity characteristics existing in the marine atmosphere.
[0006] To achieve the above purpose, the technical scheme of the present application is as follows: A method for detecting offshore non-uniform electromagnetic wave propagation loss, comprising the following steps: Step 1: deploying a plurality of buoy platforms in the target sea area, installing meteorological and hydrological sensors on the buoy platforms, and collecting meteorological and hydrological data observation values of the target sea area; Step 2: Divide the target sea area into several analysis grids. Using meteorological and hydrological data collected by buoys, simulate the meteorological and hydrological data of each analysis grid using a three-dimensional variational assimilation algorithm. Then, substitute the meteorological and hydrological data of each analysis grid into the ocean-atmosphere-wave coupling model to obtain the simulated meteorological and hydrological data values of each analysis grid, including atmospheric temperature, relative humidity, atmospheric pressure, sea surface temperature and wind speed of each analysis grid. Step 3: Substitute the atmospheric temperature, relative humidity, atmospheric pressure, and sea surface temperature of each analysis grid obtained in Step 2 into the evaporation waveguide prediction model to calculate the evaporation waveguide height of each analysis grid, thereby obtaining the atmospheric corrected refractive index profile of the evaporation waveguide of each analysis grid, and further obtaining the atmospheric refractive index of each analysis grid. Step 4: Based on the wind speed of each analysis grid obtained in Step 2, use the Shadowed model to calculate the roughness attenuation factor of each analysis grid, and further calculate the surface impedance coefficient to determine the impedance boundary conditions of the parabolic equation. Step 5: Input the transmitting antenna height and electromagnetic wave transmission frequency into the parabolic equation, combine it with the atmospheric refractive index of each analysis grid, and use the split-step Fourier algorithm to solve the parabolic equation to obtain the electromagnetic wave propagation loss of each analysis grid, thereby obtaining the non-uniform electromagnetic wave propagation loss at sea.
[0007] In the above scheme, the meteorological and hydrological data observations include atmospheric temperature, relative humidity, atmospheric pressure, sea surface temperature and wind speed.
[0008] In the above scheme, in step two, the target sea area is divided into an analysis grid with a spatial resolution of 10 kilometers, and buoys are distributed on the regional analysis grid points.
[0009] In the above scheme, in step three, the evaporation waveguide height of each analysis grid is substituted into the mathematical expression of the atmospheric corrected refractive index profile of the evaporation waveguide to obtain the atmospheric corrected refractive index profile of the evaporation waveguide for each analysis grid; when the height is less than 40m, the mathematical expression of the atmospheric corrected refractive index profile of the evaporation waveguide is as follows: ; in, For height Atmospheric corrected refractive index of the evaporation waveguide at that location The atmospheric corrected refractive index for the sea surface. Here is the height of the evaporation waveguide and the roughness length. .
[0010] In a further technical solution, the atmospheric refractive index N is calculated based on the following relationship between the atmospheric corrected refractive index of the evaporation waveguide and the atmospheric refractive index N: ; in, For height Atmospheric corrected refractive index of the evaporation waveguide at that location a z is the average Earth radius; z is the altitude. Then, the atmospheric refractive index n is calculated based on the following relationship between the atmospheric refractive index N and the atmospheric refractive index n: .
[0011] In the above scheme, the specific method for step four is as follows: First, the roughness attenuation factor is calculated using the Shadowed model. Then calculate the effective reflection coefficient. : ; in, It is the Fresnel reflection coefficient, which represents the effect of a rough sea surface on the scattering of electromagnetic waves; Then calculate the surface impedance coefficient. : ; in, For local surface glancing angle, For free space wavenumber, i It is a complex number; Thus, the impedance boundary conditions for the parabolic equation are determined: ; in, Represents the horizontally polarized electric field component or the vertically polarized electric field component. For height, This is the horizontal distance at sea level.
[0012] In the above scheme, the specific method for step five is as follows: The parabolic equation under the given evaporation waveguide conditions is expressed as follows: ; in, The electric field components representing horizontal or vertical polarization are parameters of antenna transmission altitude, electromagnetic wave transmission frequency, distance, and atmospheric refractive index. For height, The horizontal distance at sea level For free space wavenumber, i It is a complex number. For regionally non-uniform evaporation waveguide atmospheric correction refractive index profile; The parabolic equation is solved using a step-by-step Fourier transform algorithm. In each step, a Fourier transform operation is performed in conjunction with the impedance boundary conditions, and then multiplied by the atmospheric refractive index to obtain the final value. Finally, the regional non-uniform electromagnetic wave propagation loss was obtained. : ; in, It is the frequency of the electromagnetic wave.
[0013] The above technical solution provides a method for detecting the propagation loss of non-uniform electromagnetic waves at sea, which has the following beneficial effects: 1. This invention utilizes a buoy platform to achieve real-time measurement of meteorological and hydrological conditions in the target sea area; 2. This invention utilizes a buoy platform and introduces a three-dimensional variational assimilation algorithm and an ocean-air-wave coupling model to more accurately simulate regional non-uniform evaporation waveguide environments; 3. This invention utilizes a simulated regional non-uniform evaporation waveguide environment to achieve on-site accurate detection of regional non-uniform electromagnetic wave propagation loss. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.
[0015] Figure 1 This is a schematic diagram of a method for detecting the propagation loss of non-uniform electromagnetic waves at sea, as disclosed in an embodiment of the present invention. Figure 2 This is a schematic diagram of the buoy platform structure used in an embodiment of the present invention; Figure 3 A schematic diagram of grid division and data transmission for the target sea area.
[0016] In the diagram, 1 is a wind speed sensor; 2 is a communication antenna; 3 is an air inlet; 4 is an atmospheric pressure sensor; 5 is an infrared temperature sensor; 6 is a temperature and humidity sensor; 7 is a solar panel; 8 is a battery module; 9 is a data acquisition module; and 10 is a data transmission module. Detailed Implementation
[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
[0018] This invention provides a method for detecting the propagation loss of non-uniform electromagnetic waves at sea, such as... Figure 1 As shown, it includes the following steps: Step 1: Deploy multiple buoy platforms in the target sea area, install meteorological and hydrological sensors on the buoy platforms, and collect meteorological and hydrological data observations of the target sea area.
[0019] like Figure 2As shown, a solar panel 7 is installed on the buoy body of the buoy platform; a communication antenna 2 is installed on the upper mast of the buoy platform; a Stevenson screen is installed on the upper mast of the buoy platform, with a temperature and humidity sensor 6 installed inside the Stevenson screen, and a wind speed sensor 1 is installed on the upper mast of the buoy platform; an air intake disk is installed on the upper mast of the buoy platform, with an air intake hole 3 on the side of the air intake disk, and an atmospheric pressure sensor 4 is installed inside the air intake hole; an infrared temperature sensor 5 is installed on the upper mast of the buoy platform, and the infrared temperature sensor 5 is installed at an angle downwards, forming a 45° angle with the buoy platform; a data acquisition module 9 is installed inside the buoy platform, in this embodiment using an industrial control computer MIO-2263J-U0A2; a battery module 8 is installed inside the buoy platform; a data transmission module 10 is installed inside the buoy platform, in this embodiment using a wireless DTU. The data transmission module 10 is connected to the communication antenna 2, and transmits the meteorological and hydrological data collected by the data acquisition module 9 to the shore-based platform for processing via a communication satellite.
[0020] The aforementioned sensors collect atmospheric temperature, relative humidity, atmospheric pressure, sea surface temperature, and wind speed in the target sea area. The wind speed, atmospheric temperature, relative humidity, atmospheric pressure, and sea surface temperature collected by the data acquisition module 9 are transmitted to the shore-based platform via the data transmission module 10.
[0021] Step two involves dividing the target sea area into several analysis grids, with buoys distributed across these grid points. Using meteorological and hydrological data collected by the buoys, a three-dimensional variational assimilation algorithm is employed to simulate the meteorological and hydrological data for each analysis grid. This data is then substituted into the ocean-atmosphere-wave coupled model to obtain simulated meteorological and hydrological data for each grid, including atmospheric temperature, relative humidity, atmospheric pressure, sea surface temperature, and wind speed. This yields simulated values for the regionally non-uniform meteorological and hydrological data.
[0022] Step 3: Substitute the atmospheric temperature, relative humidity, atmospheric pressure, and sea surface temperature of each analysis grid obtained in Step 2 into the evaporation waveguide prediction model to calculate the evaporation waveguide height of each analysis grid. This leads to the atmospheric corrected refractive index profile of the evaporation waveguide for each analysis grid, which is the atmospheric corrected refractive index profile of the regional non-uniform evaporation waveguide. Furthermore, the atmospheric refractive index of each analysis grid is obtained. The evaporation waveguide prediction model includes, but is not limited to, the PJ model, the MGB model, and the NPS model.
[0023] Substituting the evaporation waveguide height of each analysis grid into the mathematical expression for the atmospheric corrected refractive index profile of the evaporation waveguide, we obtain the atmospheric corrected refractive index profile of the evaporation waveguide for each analysis grid. When the height is less than 40m, the mathematical expression for the atmospheric corrected refractive index profile of the evaporation waveguide is as follows: ; in, For height Atmospheric corrected refractive index of the evaporation waveguide at that location This is the atmospheric corrected refractive index for the sea surface, typically taken as 350. Here is the height of the evaporation waveguide and the roughness length. .
[0024] The atmospheric refractive index N is determined based on the following relationship between the atmospheric corrected refractive index of the evaporating waveguide and the atmospheric refractive index N: ; in, For height Atmospheric corrected refractive index of the evaporation waveguide at that location a z is the average Earth radius; z is the altitude. Then, the atmospheric refractive index n is calculated based on the following relationship between the atmospheric refractive index N and the atmospheric refractive index n: .
[0025] Step 4: Based on the wind speed of each analysis grid obtained in Step 2, use the Shadowed model to calculate the roughness attenuation factor of each analysis grid, which is the regional non-uniform roughness attenuation factor. Further calculate the surface impedance coefficient to determine the impedance boundary conditions of the parabolic equation.
[0026] The specific method is as follows: First, the roughness attenuation factor is calculated using the Shadowed model. Then calculate the effective reflection coefficient. : ; in, It is the Fresnel reflection coefficient, which represents the effect of a rough sea surface on the scattering of electromagnetic waves; Then calculate the surface impedance coefficient. : ; in, For local surface glancing angle, For free space wavenumber, i It is a complex number; Thus, the impedance boundary conditions for the parabolic equation are determined: ; in, Represents the horizontally polarized electric field component or the vertically polarized electric field component. For height, This is the horizontal distance at sea level.
[0027] Step 5: Input the parameters of the transmitting antenna height and electromagnetic wave transmission frequency into the parabolic equation, and combine them with the atmospheric refractive index of each analysis grid. Use the step-by-step Fourier algorithm to solve the parabolic equation to obtain the electromagnetic wave propagation loss of each analysis grid, and then obtain the non-uniform electromagnetic wave propagation loss at sea.
[0028] The specific method is as follows: The parabolic equation under the given evaporation waveguide conditions is expressed as follows: ; in, The electric field components representing horizontal or vertical polarization are parameters of antenna transmission altitude, electromagnetic wave transmission frequency, distance, and atmospheric refractive index. For height, To detect the distance between the radar and the target being detected, For free space wavenumber, i It is a complex number. For regionally non-uniform evaporation waveguide atmospheric correction refractive index profile; The parabolic equation is solved using a step-by-step Fourier transform algorithm. In each step, a Fourier transform operation is performed in conjunction with the impedance boundary conditions, and then multiplied by the atmospheric refractive index to obtain the final value. Then, substituting into the formula below, we obtain the regional non-uniform electromagnetic wave propagation loss. : ; in, It is the frequency of the electromagnetic wave.
[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for detecting propagation loss of non-uniform electromagnetic waves at sea, characterized in that, Includes the following steps: Step 1: Deploy multiple buoy platforms in the target sea area, install meteorological and hydrological sensors on the buoy platforms, and collect meteorological and hydrological data observations of the target sea area; Step 2: Divide the target sea area into several analysis grids. Using meteorological and hydrological data collected by buoys, simulate the meteorological and hydrological data of each analysis grid using a three-dimensional variational assimilation algorithm. Then, substitute the meteorological and hydrological data of each analysis grid into the ocean-atmosphere-wave coupling model to obtain the simulated meteorological and hydrological data values of each analysis grid, including atmospheric temperature, relative humidity, atmospheric pressure, sea surface temperature and wind speed of each analysis grid. Step 3: Substitute the atmospheric temperature, relative humidity, atmospheric pressure, and sea surface temperature of each analysis grid obtained in Step 2 into the evaporation waveguide prediction model to calculate the evaporation waveguide height of each analysis grid, thereby obtaining the atmospheric corrected refractive index profile of the evaporation waveguide of each analysis grid, and further obtaining the atmospheric refractive index of each analysis grid. Step 4: Based on the wind speed of each analysis grid obtained in Step 2, use the Shadowed model to calculate the roughness attenuation factor of each analysis grid, and further calculate the surface impedance coefficient to determine the impedance boundary conditions of the parabolic equation. Step 5: Input the transmitting antenna height and electromagnetic wave transmission frequency into the parabolic equation, combine it with the atmospheric refractive index of each analysis grid, and use the split-step Fourier algorithm to solve the parabolic equation to obtain the electromagnetic wave propagation loss of each analysis grid, thereby obtaining the non-uniform electromagnetic wave propagation loss at sea.
2. The method for detecting propagation loss of non-uniform electromagnetic waves at sea according to claim 1, characterized in that, The meteorological and hydrological data observations include atmospheric temperature, relative humidity, atmospheric pressure, sea surface temperature, and wind speed.
3. The method for detecting propagation loss of non-uniform electromagnetic waves at sea according to claim 1, characterized in that, In step two, the target sea area is divided into an analysis grid with a spatial resolution of 10 kilometers, and buoys are distributed on the regional analysis grid points.
4. The method for detecting propagation loss of non-uniform electromagnetic waves at sea according to claim 1, characterized in that, In step three, the evaporation waveguide height of each analysis grid is substituted into the mathematical expression for the atmospheric corrected refractive index profile of the evaporation waveguide to obtain the atmospheric corrected refractive index profile of each analysis grid. When the height is less than 40m, the mathematical expression for the atmospheric corrected refractive index profile of the evaporation waveguide is as follows: ； in, For height Atmospheric corrected refractive index of the evaporation waveguide at that location The atmospheric corrected refractive index for the sea surface. Here is the height of the evaporation waveguide and the roughness length. .
5. The method for detecting propagation loss of non-uniform electromagnetic waves at sea according to claim 1, characterized in that, In step three, the atmospheric refractive index N is calculated based on the following relationship between the atmospheric corrected refractive index of the evaporation waveguide and the atmospheric refractive index N: ； in, For height Atmospheric corrected refractive index of the evaporation waveguide at that location a z is the average Earth radius; z is the altitude. Then, the atmospheric refractive index n is calculated based on the following relationship between the atmospheric refractive index N and the atmospheric refractive index n: 。 6. The method for detecting propagation loss of non-uniform electromagnetic waves at sea according to claim 1, characterized in that, The specific method for step four is as follows: First, the roughness attenuation factor is calculated using the Shadowed model. Then calculate the effective reflection coefficient. : ； in, It is the Fresnel reflection coefficient, which represents the effect of a rough sea surface on the scattering of electromagnetic waves; Then calculate the surface impedance coefficient. : ； in, For local surface glancing angle, For free space wavenumber, i It is a complex number; Thus, the impedance boundary conditions for the parabolic equation are determined: ； in, Represents the horizontally polarized electric field component or the vertically polarized electric field component. For height, This is the horizontal distance at sea level.
7. The method for detecting propagation loss of non-uniform electromagnetic waves at sea according to claim 1, characterized in that, The specific method for step five is as follows: The parabolic equation under the given evaporation waveguide conditions is expressed as follows: ； in, The electric field components representing horizontal or vertical polarization are parameters of antenna transmission altitude, electromagnetic wave transmission frequency, distance, and atmospheric refractive index. For height, The horizontal distance at sea level For free space wavenumber, i It is a complex number. For regionally non-uniform evaporation waveguide atmospheric correction refractive index profile; The parabolic equation is solved using a step-by-step Fourier transform algorithm. In each step, a Fourier transform operation is performed in conjunction with the impedance boundary conditions, and then multiplied by the atmospheric refractive index to obtain the final value. Finally, the regional non-uniform electromagnetic wave propagation loss was obtained. : ； in, It is the frequency of the electromagnetic wave.