Electromagnetic wave atmospheric attenuation correction factor engineering algorithm and device

Abstract

The invention discloses an electromagnetic wave atmospheric attenuation correction factor engineering algorithm and device. The algorithm comprises the following steps: S1, obtaining zenith attenuation # imgabs0 # of a certain frequency according to data; s2, engineering estimated values A'at different angles can be simulated and calculated through zenith attenuation # imgabs 1 #; s3, fitting an exponential function by using the change rule of the angle to model the atmospheric attenuation correction factor N; s4, re-calculating the atmospheric attenuation of different frequencies by using the modeled formula; and S5, repeating the steps S2-S4, comparing a re-calculation result with an ITU theoretical calculation value, and carrying out repeated iterative fitting to obtain a constant of which the degree is less than 10 degrees and the error is less than 5%. According to the method, attenuation correction factors of different frequencies are calculated on the basis of zenith attenuation, the error range of actual attenuation is considered, the reference calculation amount of a standard ITU organization is used as comparison, attenuation correction of different frequency bands is calculated, and rapid and accurate attenuation values can be provided in the engineering application process.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication engineering applications, and particularly to an engineering algorithm and device for correcting the atmospheric attenuation of electromagnetic waves. Background Art

[0002] The attenuation of gas refers to the absorption or scattering of electromagnetic radiation by the gas, resulting in the phenomenon that the energy of electromagnetic radiation decreases when passing through the gas. The ITU-R P.618-13 Recommendation (12 / 2017), "Propagation data and prediction methods required for the design of land-to-air telecommunication systems", states that usually at elevation angles above 10 degrees, depending on different propagation conditions, only gas attenuation, rain and cloud attenuation, and possible scintillation effects are relatively significant. Among them, the ITU-R P.676-13 Recommendation (08 / 2022), "Attenuation of radio waves in atmospheric gases and related effects", gives a complete method for calculating the attenuation of atmospheric gases.

[0003] The attenuation caused by atmospheric gases entirely originates from absorption and is mainly related to frequency, elevation angle, height above the horizontal plane, and water vapor density (absolute humidity), etc. At frequencies below 10 GHz, it can usually be ignored. At frequencies above 10 GHz, its importance gradually increases, especially at low elevation angles.

[0004] According to the ITU-R P.676 standard, the line-by-line calculation method for gas attenuation is used for atmospheric attenuation and analysis. Line-by-line calculation means calculating each spectral line separately to obtain the gas attenuation within the entire spectral range. This method is usually used to accurately calculate the spectral absorption and emission characteristics of gases and to study the spectral properties of gases. At any air pressure, any temperature, and any humidity, by accumulating the spectral lines of oxygen and water vapor respectively, the specific attenuation up to 1000 GHz frequency mainly caused by dry air and water vapor can be accurately calculated.

[0005] Figure 1 The specific attenuation (step size is 1 GHz) in the 0-1000 GHz frequency band under two conditions of air pressure 1013.25 Pa, temperature 15 °C, water vapor density 7.5 g / m³ (standard) and dry air (dry) calculated using the prediction method is given.

[0006] According to the specific attenuation standard chart provided by ITU-R P.676-13, the specific attenuation values corresponding to the frequency range of 0-100 GHz at air pressure 1013.25 Pa, temperature 15 °C, and water vapor density 7.5 g / m³ (standard) are as Figure 2 shown.

[0007] During the electromagnetic wave communication with frequencies less than 100 GHz, it can be seen that the attenuation caused by electromagnetic waves passing through the atmosphere forms two peaks, approximately at 22 GHz and 60 GHz.

[0008] High-precision gas radiation calculations are very important in scientific research and engineering applications in multiple disciplines. The line-by-line method, as the most accurate gas radiation model, is difficult to use in practical applications due to its complex calculation process and high time consumption. It is more used as a precision scale to measure the calculation accuracy of other radiation models. Summary of the invention

[0009] In order to solve the problem of complex calculation process of the original line-by-line method, the present invention provides an engineering algorithm for the atmospheric attenuation correction factor of electromagnetic waves, simplifies the original calculation formula, forms a fast calculation method for atmospheric attenuation in satellite communications with theoretical basis, and achieves consistency between the atmospheric attenuation calculated by simulation and the measured in actual engineering applications.

[0010] The specific plan is as follows: An electromagnetic wave atmospheric attenuation correction factor engineering algorithm comprises the following steps: S1, obtain the zenith attenuation of a certain frequency based on the data ; The zenith attenuation is the attenuation value of the electromagnetic wave passing through the atmosphere when the elevation angle is 90 degrees; S2, attenuation through the zenith The engineering estimate value A' can be simulated and calculated at different angles;

[0011] in, is the theoretically estimated value of zenith attenuation, in dB. is the elevation angle of the measuring station; S3, using the angle variation law to fit the exponential function to model the atmospheric attenuation correction factor N; S4, use the modeled formula to recalculate the atmospheric attenuation of different frequencies. Specifically, correct the engineering estimate A' according to the correction factor N to obtain the final atmospheric attenuation value. ; S5, repeat steps S2-S4, compare the recalculated result with the ITU theoretical calculated value, repeatedly iterate and fit to find a constant that is less than 10 degrees and within an error of 5%. The calculation formula of the correction factor N is summarized as follows ;in, is a natural constant, is the elevation angle of the measuring station, in degrees.

[0012] Preferably, in step S1, the target frequency range is 2-100 GHz, with an interval of 1 GHz.

[0013] The present invention also discloses a device for realizing an engineering algorithm for an electromagnetic wave atmospheric attenuation correction factor, comprising: A data acquisition module for acquiring zenith attenuation data at a certain frequency; A simulation calculation module for calculating engineering estimation values at different angles based on the zenith attenuation; A modeling module for modeling the atmospheric attenuation correction factor N; A recalculation module for recalculating the atmospheric attenuation using the modeled formula; A comparison module for comparing the recalculation results with the ITU theoretical calculation values; A correction module for repeatedly iterating and fitting to find constants that meet the error requirements and summarizing the calculation formula for the correction factor N.

[0014] The present invention also discloses a computer-readable storage medium with a computer program stored thereon. After the computer program runs, it executes the algorithm described in any one of the above.

[0015] The present invention also discloses a computer system, including a processor and a storage medium. The storage medium stores a computer program, and the processor reads and runs the computer program from the storage medium to execute the algorithm described in any one of the above.

[0016] The beneficial effects of the present invention are as follows: Based on the zenith attenuation, the present invention calculates the attenuation correction factors at different frequencies, considers the error range of the actual attenuation, uses the reference calculation value of the standard ITU organization for comparison, and calculates the attenuation correction amounts at different frequency bands, which can provide fast and accurate attenuation values in the engineering application process.

[0017] Compared with the ITU standard calculation value, above an elevation angle of 10 degrees, the error does not exceed 5%. It solves the complex calculation process of the original line-by-line method, simplifies the original calculation formula, forms a fast calculation method for atmospheric attenuation in satellite communication with a theoretical basis, and achieves the consistency between the simulated atmospheric attenuation and the measured value in actual engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is the specific attenuation value standard diagram (0 - 1000 GHz) of ITU-R P.676-13; Figure 2 It is the specific attenuation value standard diagram (0 - 100 GHz) of ITU-R P.676-13; Figure 3 It is a schematic diagram of atmospheric attenuation and zenith attenuation path. Specific Embodiments

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Based on the ITU atmospheric attenuation theory method, for the relationship between the zenith attenuation of different frequencies and the elevation angle of the measuring station, the present invention uses software to deduce an engineering simplified algorithm. By analyzing the comparison between the engineering calculation results and the theoretical calculation results, the attenuation function can be accurately determined through the elevation angle parameter of the measuring station and the change of the attenuation amount, so as to calculate more conveniently and obtain the atmospheric attenuation value generated when passing through the atmosphere at different frequencies (2 - 100 G, with an interval of 1 G) from the perspective of engineering practice application. The basic principle and process are as Figure 3 shown.

[0022] As shown in the figure, h1 is the schematic height of the low-density atmosphere layer, and h2 is the schematic height of the high-density atmosphere layer. Point A is the location of the measuring station, communicating with the satellite at point B. At the elevation angle of , the length passing through the atmosphere is L. R is the radius of the earth, and H is the theoretical height of the atmosphere affecting the communication electromagnetic wave. Due to its different densities, the density of the atmosphere gradually decreases from a higher density near the ground to a lower density.

[0023] When considering the zenith attenuation corresponding to H, then L corresponds to the in-atmosphere propagation path when the corresponding elevation angle is for the atmospheric attenuation value. According to this idea, only by converting the zenith attenuation into the atmospheric attenuation value at the elevation angle of , and then subtracting the value of the correction factor N corresponding to the frequency, the atmospheric attenuation value of a certain frequency band corresponding to the length L at the measuring station can be obtained.

[0024] Specifically, an engineering algorithm for the correction factor of electromagnetic wave atmospheric attenuation includes the following steps: S1. Obtain the zenith attenuation of a certain frequency from the data; the zenith attenuation is the attenuation value of the electromagnetic wave passing through the atmosphere when the elevation angle is 90 degrees. Among them, the target frequency range is 2 - 100 GHz, with an interval of 1 GHz.

[0025] S2. Through the zenith attenuation , the engineering estimated value A' at different angles can be simulated and calculated;

[0026] Among them, is the theoretical calculation value of zenith attenuation, with the unit of dB, is the elevation angle of the station.

[0027] S3. Use the variation law of the angle to fit an exponential function to model the atmospheric attenuation correction factor N.

[0028] S4. Use the modeled formula to recalculate the atmospheric attenuation at different frequencies. Specifically, correct the engineering estimation value A' according to the correction factor N to obtain the final atmospheric attenuation value .

[0029] S5. Repeat steps S2 - S4, compare the recalculation results with the ITU theoretical calculation values, and iteratively fit to find the constant that meets the requirements of being below 10 degrees and having an error within 5%. That is: optimize the correction factor parameters by comparing with the ITU theoretical calculation values until the elevation angle ≥ 10° and the error ≤ 5%; summarize the calculation formula of the correction factor N as follows ; Among them, is the natural constant, is the elevation angle of the station, with the unit of degree.

[0030] The present invention also discloses a device for implementing the engineering algorithm of the electromagnetic wave atmospheric attenuation correction factor, including: A data acquisition module for acquiring zenith attenuation data of a certain frequency; A simulation calculation module for calculating the engineering estimation values at different angles according to the zenith attenuation; A modeling module for modeling the atmospheric attenuation correction factor N; A recalculation module for recalculating the atmospheric attenuation using the modeled formula; A comparison module for comparing the recalculation results with the ITU theoretical calculation values; A correction module for iteratively fitting to find the constant that meets the error requirements and summarizing the calculation formula of the correction factor N.

[0031] Example: Taking the working frequency of 14 GHz as an example, calculate the attenuation correction factor N, and the results are shown in Table 1. It meets the requirement of having an error within 5% above 10 degrees.

[0032] Table 1: Attenuation correction results for a working frequency of 14 GHz

[0033]

[0034] When calculating the attenuation of electromagnetic waves passing through the atmosphere using the steps of the present invention, the total time consumed by an ordinary industrial computer is less than 1 ms. While the line-by-line method takes more than 1 s. The calculation time of the present invention is reduced by three orders of magnitude.

[0035] Based on the zenith attenuation, the present invention calculates the attenuation correction factors for different frequencies. Considering the error range of the actual attenuation, using the reference calculation values of the standard ITU organization for comparison, and calculating the attenuation correction amounts for different frequency bands, it can provide fast and accurate attenuation values during the engineering application process. Moreover, compared with the ITU standard calculation values, the error of the present invention is not more than 5% when the elevation angle is above 10 degrees. It solves the complex calculation process of the original line-by-line method, simplifies the original calculation formula, and forms a fast calculation method for atmospheric attenuation in satellite communication with a theoretical basis, achieving the consistency between the simulated atmospheric attenuation and the measured values in actual engineering applications.

[0036] The present invention also discloses a computer-readable storage medium and a computer system. Among them, the medium stores a computer program. After the computer program runs, it executes the algorithm described in any one of the above. The computer system includes a processor and a storage medium. The storage medium stores a computer program, and the processor reads and runs the computer program from the storage medium to execute the algorithm described in any one of the above.

[0037] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system. Skilled artisans may implement the described functionality in different ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

[0038] The foregoing description of the disclosure has been provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electromagnetic wave atmospheric attenuation correction factor engineering algorithm, characterized in that: The following steps are involved: S1, obtain the zenith attenuation of a certain frequency based on the data ; The zenith attenuation is the attenuation value of the electromagnetic wave passing through the atmosphere when the elevation angle is 90 degrees; S2, attenuation through the zenith The engineering estimate value A' can be simulated and calculated at different angles; ； in, is the theoretically estimated value of zenith attenuation, in dB. is the elevation angle of the measuring station; S3, using the angle variation law to fit the exponential function to model the atmospheric attenuation correction factor N; S4, use the modeled formula to recalculate the atmospheric attenuation of different frequencies. Specifically, correct the engineering estimate A' according to the correction factor N to obtain the final atmospheric attenuation value. ; S5, repeat steps S2-S4, compare the recalculated result with the ITU theoretical calculated value, repeatedly iterate and fit to find a constant that is less than 10 degrees and within an error of 5%. The calculation formula of the correction factor N is summarized as follows ;in, is a natural constant, is the elevation angle of the measuring station, in degrees.

2. The algorithm according to claim 1, characterized in that: In step S1, the target frequency range is 2-100 GHz with an interval of 1 GHz.

3. A device for implementing the electromagnetic wave atmospheric attenuation correction factor engineering algorithm as described in any one of claims 1-2, characterized in that: include: Data acquisition module, used to obtain zenith attenuation data of a certain frequency; A simulation calculation module is used to calculate engineering estimates at different angles based on zenith attenuation; A modeling module, used to model the atmospheric attenuation correction factor N; The recalculation module is used to recalculate the atmospheric attenuation using the modeled formula; Comparison module, used to compare the recalculated results with the ITU theoretical calculation values; The correction module is used to repeatedly iterate and fit to obtain a constant that meets the error requirements and summarize the calculation formula of the correction factor N.

4. A computer-readable storage medium, characterized in that: A computer program is stored on the medium, and after the computer program is run, the algorithm as described in any one of claims 1 to 2 is executed.

5. A computer system, characterized in that: The method comprises a processor and a storage medium, wherein a computer program is stored in the storage medium, and the processor reads and runs the computer program from the storage medium to execute the algorithm as claimed in any one of claims 1 to 2.

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