A comprehensive simulation analysis method and system for shortwave beyond-line-of-sight communication

Abstract

A short-wave over-the-horizon communication comprehensive simulation analysis method is designed for the problem of cascade and comprehensive analysis of antenna radiation characteristics and radio propagation environment. The method includes the simulation of short-wave antenna radiation characteristics, the construction of ionosphere model, the simulation of short-wave signal propagation path in ionosphere by ray tracing technology, the comprehensive calculation of signal energy distribution in the drop area by integrating antenna characteristics, ionosphere environment and propagation mechanism, and the realization of comprehensive evaluation and analysis of short-wave over-the-horizon communication reachable range. The method can comprehensively master the signal propagation path and fading characteristics from the radiation source to the receiving end, and provide guidance and basis for antenna selection, erection, coverage range analysis and communication quality estimation in the practical engineering application of short-wave over-the-horizon communication.

Description

Technical Field

[0001] This invention belongs to the field of shortwave communication, and particularly relates to the comprehensive simulation and analysis of shortwave beyond-line-of-sight communication. Background Technology

[0002] Shortwave over-the-horizon communication relies on the ionospheric reflection mechanism to achieve long-range wireless communication beyond the horizon, and is widely used in emergency communication, remote command, military deployment, and maritime and air communication. Its link quality and communication performance typically depend on the coupling effects of multiple complex factors, including antenna radiation characteristics, ionospheric structure, and radio wave propagation paths. Therefore, establishing a complete, dynamic, and scalable integrated simulation and analysis system is crucial for ensuring the reliability of shortwave communication links, adapting to complex battlefield environments, and achieving precise deployment planning.

[0003] Currently, shortwave communication systems commonly employ modular modeling in simulation and evaluation, where antenna radiation characteristics, ionospheric propagation environment, and reception characteristics are modeled and analyzed independently. While this approach offers advantages in local optimization of individual subsystems, it can hinder effective information transfer between modules at the system-level. For instance, in most current systems, antenna radiation characteristics are typically input into the radio wave propagation module as static parameters or pre-defined models, resulting in a lack of dynamic response capabilities to factors such as frequency, incident angle, and time-varying ionospheric characteristics. Conversely, while the radio wave propagation path is influenced by complex environmental factors such as ionospheric electron density distribution, magnetic fields, and solar activity, their feedback effects on the effective radiation direction and power coverage area of ​​the antenna are not considered in the modeling. Therefore, effective cascading and comprehensive analysis of antenna radiation characteristics and the radio wave propagation environment is urgently needed. Summary of the Invention

[0004] To address the problem of cascading and comprehensive analysis of antenna radiation characteristics and radio wave propagation environment, this invention provides a comprehensive simulation analysis method for shortwave beyond-line-of-sight communication. This method can perform integrated simulation research and simulation of antenna radiation characteristics and signal propagation process, obtain the signal propagation path and fading characteristics from the radiation source to the receiving end, realize the comprehensive evaluation and analysis of the reachable range of shortwave beyond-line-of-sight communication, and predict the quality and reliability of communication links.

[0005] According to one aspect of the present invention, a comprehensive simulation and analysis method for shortwave beyond-line-of-sight communication is provided, comprising:

[0006] Within the shortwave band, select a frequency to simulate the radiation characteristics of the antenna, and generate a gain matrix based on elevation and azimuth angles.

[0007] Based on the empirical model of the ionosphere, a three-dimensional ionospheric plasma grid and collision frequency grid are generated around the emission point to construct an ionospheric channel model;

[0008] At the transmission point, an electromagnetic wave signal of a selected frequency is transmitted according to the aforementioned elevation and azimuth angles.

[0009] Based on the constructed ionospheric channel model, combined with the numerical ray tracing method, the propagation process of the electromagnetic wave signal is simulated and calculated to obtain the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss.

[0010] Based on the ray tracing simulation results, identify the rays with landing points and their locations, and calculate the total loss of electromagnetic waves during propagation in the ionosphere.

[0011] By combining antenna gain, ray tracing simulation results, and total loss, the energy of the landing area of ​​a ray with a landing point is calculated.

[0012] Interpolation is performed on the calculated energy of the landing area to achieve a comprehensive analysis of the reachability range of shortwave beyond-line-of-sight communication.

[0013] As a further technical solution, the method also includes:

[0014] In the selected simulated scenario, a shortwave antenna is erected, and the antenna's erection position and attitude are determined based on the three-dimensional spatial coordinates and tilt angle.

[0015] The gain matrix of the antenna is generated by calculating the elevation and azimuth angles that change in equal steps.

[0016] As a further technical solution, based on the empirical model of the ionosphere, a three-dimensional ionospheric plasma grid and a collision frequency grid are generated around the emission point. The dimensions of the grid include longitude, latitude, and height. The height of the three-dimensional grid is the range of the ionosphere, and the longitude and latitude range of the three-dimensional grid is estimated based on the great circle distance of shortwave propagation.

[0017] As a further technical solution, after obtaining the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss, the method further includes:

[0018] The obtained propagation paths and ionospheric absorption losses are stored according to elevation and azimuth angles.

[0019] As a further technical solution, the location of the ray with a landing point and the location of the landing point are identified, including:

[0020] During ray tracing, all rays with valid landing points are marked as 1, and rays that escape at the top of the ionosphere or terminate at high altitudes are marked as -2 or -3.

[0021] All ray markers are scanned. If a ray marked as 1 is encountered, the landing point of the ray, the propagation path of the electromagnetic wave signal on the ray, and the ionospheric absorption loss are selected as the basic data source for subsequent energy superposition and interpolation analysis of the landing area.

[0022] As a further technical solution, the total loss of electromagnetic waves during propagation in the ionosphere is calculated, including:

[0023]

[0024] Where Li represents ionospheric absorption loss, Yp represents ionospheric additional system loss, La represents ground scattering loss, and Lps represents free space transport loss.

[0025]

[0026] Where f is the frequency and p is the path length of the electromagnetic wave.

[0027] As a further technical solution, the energy E of the landing region of the ray with a landing point is calculated as follows:

[0028] E = Pt + G1 - L

[0029] Where Pt is the transmit power, L is the total loss, and G1 is the antenna gain; the direction of the antenna gain G1 matches the transmission direction of the ray, and is indexed and matched by the elevation angle and azimuth angle.

[0030] As a further technical solution, interpolation is performed on the calculated landing area energy, including:

[0031] A bilinear interpolation algorithm is used to perform bilinear interpolation on the calculated ray energy, transforming the discrete and finite number of ray energy values ​​into a continuous, visualized, and analyzable regional coverage map.

[0032] As a further technical solution, to address the error of the interpolation result extending towards the center, the central hole is masked as follows:

[0033] For data where the energy of discrete ray impact points is distributed in a non-closed ring around the emission point, the edges in the Delaunay triangulation are filtered by the α-shape principle to extract the boundary contours that fit the true shape of the scattered point set, thus obtaining a closed region. Interpolation is only performed within the closed region.

[0034] For data where the energy of discrete rays is distributed in a closed ring around the emission point, for a set of rays at each azimuth angle, find the closest point to the emission point. After finding the closest points to the emission point at all azimuth angles, the inner ring boundary is obtained. Fit the points of the inner boundary to a closed inner boundary curve, perform masking on the closed region, and after interpolation, set the masked points to null values, retaining only the energy interpolation results outside the closed region.

[0035] According to one aspect of the present invention, a shortwave beyond-line-of-sight communication integrated simulation and analysis system is provided, comprising:

[0036] The first main module is used to simulate the radiation characteristics of the antenna at a selected frequency in the shortwave band and generate a gain matrix according to the elevation and azimuth angles.

[0037] The second main module is used to generate a three-dimensional ionospheric plasma grid and a collision frequency grid around the emission point based on the ionospheric empirical model, and to construct an ionospheric channel model.

[0038] The third main module is used to transmit electromagnetic wave signals of a selected frequency at the transmission point according to the elevation angle and azimuth angle.

[0039] The fourth main module is used to simulate and calculate the propagation process of the electromagnetic wave signal based on the constructed ionospheric channel model and combined with the numerical ray tracing method, so as to obtain the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss.

[0040] The fifth main module is used to find the rays with landing points and their locations based on the ray tracing simulation results, and to calculate the total loss of electromagnetic waves during propagation in the ionosphere.

[0041] The sixth main module is used to calculate the energy of the landing area of ​​a ray with a landing point by combining the antenna gain and ray tracing simulation results.

[0042] The seventh main module is used to interpolate the calculated energy of the landing area to achieve a comprehensive analysis of the reachability range of shortwave beyond-line-of-sight communication.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1. The shortwave beyond-line-of-sight communication integrated simulation analysis method provided by this invention uses an open algorithm interface to simulate the radiation characteristics of the antenna, connecting theoretical design with practical application, ensuring that the antenna achieves the optimal balance in terms of efficiency, performance, and cost, while reducing development risks, and plays an important role in engineering design and practical application.

[0045] 2. The shortwave over-the-horizon communication integrated simulation analysis method provided by this invention can perform integrated simulation research and simulation of antenna radiation characteristics and signal propagation process, obtain the signal propagation path and fading characteristics from the radiation source to the receiving end, realize the comprehensive evaluation and analysis of the reachable range of shortwave over-the-horizon communication, predict the quality and reliability of communication links, and provide guidance and basis for antenna selection, installation, coverage analysis and communication quality estimation in the practical engineering application of shortwave over-the-horizon communication. Attached Figure Description

[0046] 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. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a flowchart of the shortwave beyond-line-of-sight communication integrated simulation analysis method provided in the embodiments of the present invention;

[0048] Figure 2 The radiation pattern of a 15-meter long and 0.1-meter wide dipole antenna according to an embodiment of the present invention has a frequency of 7MHz;

[0049] Figure 3 The radiation pattern of a 15-meter long and 0.1-meter wide dipole antenna in one embodiment of the present invention is shown in the direction of the STL reflector, with a frequency of 7MHz.

[0050] Figure 4 The total loss diagram for ray tracing in one embodiment of the present invention is shown, with the ionospheric time set to 8:00 AM on December 22, 2009, and the frequency set to 7 MHz.

[0051] Figure 5 This is an energy fall-off map according to an embodiment of the present invention, with the ionospheric time set to 8:00 AM on December 22, 2009, and no antenna is included;

[0052] Figure 6 This is an energy fall-off map of an embodiment of the present invention. The ionospheric time is set to 8:00 on December 22, 2009. The added antenna is a 15-meter long and 0.1-meter wide dipole antenna with a frequency of 7MHz, and is introduced into an STL reflector.

[0053] Figure 7 This is an energy fall-off map according to an embodiment of the present invention. The ionospheric time is set to 18:00 on September 22, 2009, the frequency is 7MHz, and no antenna is added.

[0054] Figure 8This is an energy fall-off map of an embodiment of the present invention. The ionospheric time is set to 18:00 on September 22, 2009. The antenna is a 15-meter long and 0.1-meter wide dipole antenna with a frequency of 7MHz and no STL reflector.

[0055] Figure 9 This is an energy fall-off map of an embodiment of the present invention. The ionospheric time is 7:00 on December 23, 2009. The antenna is a 15-meter long and 0.1-meter wide dipole antenna. The radio wave frequency and antenna are set to 14MHz during ray tracing, and there is no STL reflector. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to 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 those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the scope of the invention.

[0058] This invention provides a comprehensive simulation and analysis method for shortwave beyond-line-of-sight communication. It simulates the radiation characteristics of a shortwave antenna, constructs an ionospheric model, and uses ray tracing technology to simulate the propagation path of shortwave signals in the ionosphere. By integrating antenna characteristics, ionospheric environment, and propagation mechanism, it calculates the energy distribution of the signal's landing area, thereby achieving a comprehensive evaluation and analysis of the reachability of shortwave beyond-line-of-sight communication.

[0059] like Figure 1 As shown, the implementation of this invention includes the following steps:

[0060] Step S1: Set up a shortwave antenna in a certain scenario. Select a frequency of 7MHz within the 3~30MHz band to simulate the radiation characteristics of the antenna. Generate a gain matrix according to the elevation angle and azimuth angle. The azimuth angle can be set to -180:1:179 and the elevation angle can be set to 10:0.5:50.

[0061] It should be noted that the deployment of shortwave antennas in specific scenarios can be provided by STL files (such as STL files for simulating a flat ground plane). An interface is provided here for users to import STL files and create their own simulation scenarios. The antenna's mounting position and attitude are determined based on three-dimensional spatial coordinates and tilt angles. For example, for a single 15-meter long and 0.1-meter wide dipole antenna with a frequency of 7MHz, the simulated radiation characteristics are as follows... Figure 2 As shown. The imported STL scene consists of two mutually perpendicular 50×50 planes, with the antenna installed at [0 0 0] and at a 0-degree angle. The results of the radiation characteristic simulation are as follows. Figure 3 As shown. Figure 3 In order to be in Figure 2 Based on this, import the antenna pattern of the STL reflector, and from... Figure 2 and Figure 3 It can be seen that the addition of the reflective surface creates a main lobe with a clear directionality.

[0062] Step S2: Based on the IRI2016 model, a three-dimensional ionospheric plasma grid and a collision frequency grid are generated around the emission point to construct an ionospheric channel model.

[0063] It should be noted that a three-dimensional (longitude × latitude × altitude) ionospheric plasma grid and collision frequency grid are generated around the emission point. The height of the three-dimensional grid represents the extent of the ionosphere. With a ray hop count of 1, the latitude and longitude range is estimated based on the great circle distance of shortwave propagation, and must cover both the emission point and the entire shortwave propagation range. For example, assuming the emission point is located at 121.5 degrees east longitude and 31 degrees north latitude, the generated three-dimensional ionospheric grid has an altitude grid of 60:2:460, a longitude grid of 89:1.5:155, and a latitude grid of 6:0.5:56. The ionospheric grid was generated at 8:00 AM on December 22, 2009.

[0064] Step S3: At the emission point, emit an electromagnetic wave signal of the selected frequency according to the elevation and azimuth angles in step S1, i.e., emit electromagnetic waves at an azimuth angle of -180:1:179 and an elevation angle of 10:0.5:50. The frequency range should be between 3 and 30 MHz. Assume the ray frequency is 7 MHz.

[0065] Step S4: In the ionospheric channel model constructed in step S2, the propagation process of the electromagnetic wave signal in step S3 is simulated and calculated based on the numerical ray tracing method to obtain its propagation path in the ionosphere and the corresponding ionospheric absorption loss.

[0066] It should be noted that in step S4, based on the numerical ray tracing method, the propagation process of the electromagnetic wave signal in step S3 is simulated and calculated with a ray hop count of 1. The resulting propagation path and ionospheric absorption loss are stored according to the elevation and azimuth angles of step S1 for easy retrieval in subsequent calculations. To improve the accuracy of the results, the step sizes of the azimuth and elevation angles are set to be small, and the number of rays is large; to improve the calculation speed, the rays are traced in blocks along the azimuth angle.

[0067] Step S5: Based on the ray tracing simulation results from Step S4, identify the rays with landing points and their locations, and calculate the total loss of the electromagnetic wave during propagation in the ionosphere. The loss obtained based on the above parameters is as follows: Figure 4 As shown.

[0068] It should be noted that the method for finding the rays with landing points and their locations in step S5 is as follows: During ray tracing, all rays with valid landing points are marked as 1. If a ray escapes at the top of the ionosphere or terminates at high altitude, it is marked as -2 or -3. The markings of all rays are scanned. If a ray marked as 1 is encountered, the landing point location of the ray and the propagation path, ionospheric absorption loss, and other information from step S4 are selected. This information is used as the basic data source for subsequent energy superposition and interpolation analysis of the landing area.

[0069] The total loss L of the electromagnetic wave propagating in the ionosphere as described in step S5 is:

[0070] (1)

[0071] Where L is in dB, Li is the ionospheric absorption loss, Yp is the ionospheric additional system loss (empirically set to 18 dB), La is the ground scattering loss (La = 0 in the 1-hop case), and Lps is the free space transmission loss.

[0072] (2)

[0073] Where Lps and Li are in dB, f is the frequency in MHz, and p represents the path length of the radio wave in km.

[0074] Step S6: Combining the antenna gain from step S1 and the ray tracing results from steps S4 and S5, calculate the energy of the landing area of ​​the ray with a landing point.

[0075] It should be noted that step S6 describes the calculation of the landing area energy by combining the antenna gain and ray tracing results. This is achieved by first calculating the loss during ray tracing and then superimposing the results in dB. The specific expression is as follows:

[0076] E = Pt + G1 - L (3)

[0077] Where E represents the energy of the falling area, Pt is the transmission power, L is the total loss mentioned above, and G1 is the antenna gain; the direction of the antenna gain G1 must match the direction of the ray's emission, and is matched by the elevation angle and azimuth angle.

[0078] Step S7: Interpolate the energy in the landing area in S6 to achieve a comprehensive assessment of the reachability range of shortwave beyond-line-of-sight communication.

[0079] It should be noted that step S7 describes the interpolation of the energy in the impact region from step S6. A bilinear interpolation algorithm is used to interpolate the energy data obtained in step S6. Because the energy at the discrete ray impact point is distributed in a closed or open ring around the emission point, the interpolation result may incorrectly extend towards the center. Therefore, a masking process is needed to address the central void. The specific processing method is as follows:

[0080] For data with a non-closed ring distribution, the edges in the Delaunay triangulation are filtered by the α-shape principle, and the boundary contours that fit the true shape of the scatter point set are extracted to obtain closed regions. Interpolation is only performed within the closed regions.

[0081] For energy data distributed in a closed ring, for a set of rays at each azimuth angle, the closest landing point to the emission point is found. After finding the closest landing points at all azimuth angles, the inner ring boundary is obtained. A closed inner boundary curve is fitted to the landing points of the inner boundary. The region within the closed area is masked, and after interpolation, the masked points are set to null values, retaining only the energy interpolation results outside this region. This suppresses spurious spread. Finally, the discrete, finite number of ray landing point energy values ​​are transformed into a continuous, visualized, and analyzable region coverage map to evaluate the reachability and energy distribution characteristics of shortwave over-the-horizon communication. Based on the above parameter settings and methods, the reachability and energy distribution of shortwave over-the-horizon communication are as follows: Figure 6 As shown.

[0082] Figure 5 Without an antenna, the transmitter power was set to 1kW. Figure 4 A calculated energy distribution map; Figure 6 To set the transmitter power to 1kW and the frequency to 7MHz, a 15-meter long and 0.1-meter wide dipole antenna is added, and the antenna is inserted into the STL reflector. Figure 4 A calculated energy distribution map. (Example) Figure 5 and Figure 6 As shown, the horizontal axis represents longitude, the vertical axis represents latitude, and the color represents the magnitude of energy in the landing area; from Figure 5 It can be seen that the energy is higher closer to the launch point, and gradually decreases further away from the launch point. Figure 6 It can be seen that when adding Figure 3 As shown, after the antenna gain was increased, the energy distribution in the falling area changed, and some low-energy regions appeared in some places.

[0083] Figure 7 An energy fall-off map with the ionospheric time set to 18:00 on September 22, 2009, the frequency to 7MHz, the transmitter power to 1kW, and no antenna added. Figure 8 This is an energy drop plot with the ionospheric time set to 18:00 on September 22, 2009, the transmitter power set to 1kW, the antenna a 15-meter long and 0.1-meter wide dipole antenna, the frequency 7MHz, and no STL reflector. (Source: [Insert Source Here]) Figure 7 It can be seen that the energy is higher closer to the transmission point and gradually decreases further away from the transmission point. However, after adding an omnidirectional dipole antenna, such as... Figure 8 As shown, the energy in the inner circle, which is closer to the launch point, is slightly less than the energy in areas farther from the launch point.

[0084] Figure 9 This is an energy fall-off diagram according to an embodiment of the present invention. The ionospheric time is 7:00 AM on December 23, 2009. The antenna is a 15-meter long and 0.1-meter wide dipole antenna. During ray tracing, the radio wave frequency and antenna are set to 14 MHz, the transmitter power is set to 1 kW, and there is no STL reflector. It can be seen from the figure that when the frequency is set to 14 MHz, the energy fall-off area is far from the emission point, and the energy fall-off area becomes smaller.

[0085] It should be noted that the embodiments of the present invention provide specific implementation methods for the single-hop case, but are not limited to the aforementioned embodiments. The present invention can also be applied to the multi-hop case, and in the multi-hop case, if the data of the first hop is taken for calculation, the calculation process is the same as that in the single-hop case.

[0086] The implementation of the various embodiments of the present invention is based on programmed processing by a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a shortwave beyond-line-of-sight communication integrated simulation and analysis system, which is used to execute a shortwave beyond-line-of-sight communication integrated simulation and analysis method from the above method embodiments.

[0087] The system comprises: a first main module for simulating the radiation characteristics of an antenna at a selected frequency within the shortwave band, generating a gain matrix based on elevation and azimuth angles; a second main module for generating a three-dimensional ionospheric plasma grid and collision frequency grid around the transmission point based on an empirical ionospheric model, constructing an ionospheric channel model; a third main module for transmitting an electromagnetic wave signal at a selected frequency at the transmission point according to the aforementioned elevation and azimuth angles; a fourth main module for simulating the propagation process of the electromagnetic wave signal based on the constructed ionospheric channel model and using numerical ray tracing methods, obtaining the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss; a fifth main module for identifying the rays with landing points and their locations based on the ray tracing simulation results, and calculating the total loss of the electromagnetic wave during ionospheric propagation; a sixth main module for calculating the landing area energy of the rays with landing points by combining antenna gain and ray tracing simulation results; and a seventh main module for interpolating the calculated landing area energy to achieve a comprehensive analysis of the reachability range of shortwave beyond-line-of-sight communication.

[0088] This invention provides a shortwave beyond-line-of-sight communication integrated simulation and analysis system. Addressing the urgent need for effective cascading and integrated analysis of antenna radiation characteristics and radio wave propagation environment, this system employs several modules to perform integrated simulation research and analysis linking antenna radiation characteristics and signal propagation processes. It obtains the signal propagation path and fading characteristics from the radiation source to the receiving end, enabling comprehensive evaluation and analysis of the reachable range of shortwave beyond-line-of-sight communication, and predicting the quality and reliability of communication links.

[0089] It should be noted that the system embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above system embodiments provided by the present invention. As long as those skilled in the art can improve the modules in the above system embodiments by referring to the specific technical solutions in other method embodiments and combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, on the basis of the above system embodiments, and on the premise of ensuring the practicality of the technical solutions, they can obtain corresponding system-like embodiments for implementing the methods in other method-like embodiments.

[0090] In summary, this invention presents a comprehensive simulation and analysis method for shortwave over-the-horizon communication, addressing the problem of cascading and integrated analysis of antenna radiation characteristics and radio wave propagation environment. This method includes simulating the radiation characteristics of a shortwave antenna, constructing an ionospheric model, simulating the propagation path of shortwave signals in the ionosphere using ray tracing technology, and calculating the energy distribution of the signal's landing area by integrating antenna characteristics, the ionospheric environment, and propagation mechanisms. This enables a comprehensive evaluation and analysis of the reachability of shortwave over-the-horizon communication. This method can comprehensively grasp the signal propagation path and fading characteristics from the radiation source to the receiving end, providing guidance and basis for antenna selection, installation, coverage analysis, and communication quality estimation in practical engineering applications of shortwave over-the-horizon communication.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for short-wave over-the-horizon communication comprehensive simulation analysis, characterized in that, The method comprises the following steps: Radiation characteristics of the antenna at a selected frequency in the short wave band are simulated to generate a gain matrix according to the elevation angle and the azimuth angle; Based on an ionospheric empirical model, a three-dimensional ionospheric plasma grid and a collision frequency grid are generated around the transmitting point to construct an ionospheric channel model; At the transmitting point, an electromagnetic wave signal at the selected frequency is transmitted according to the elevation angle and the azimuth angle; Based on the constructed ionospheric channel model, the propagation process of the electromagnetic wave signal is simulated by combining a numerical ray tracing method to obtain the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss; According to the ray tracing simulation result, the rays with landing points and the positions of the landing points are found out, and the total loss of the electromagnetic wave in the ionospheric propagation process is calculated; The landing area energy of the rays with landing points is calculated by combining the antenna gain, the ray tracing simulation result and the total loss; The calculated landing area energy is interpolated to realize comprehensive analysis of the short wave over-the-horizon communication reachable range; for the central error expansion of the interpolation result, the following mask processing is performed on the central void: For the data in which the discrete ray landing point energy is distributed in a non-closed annular shape around the transmitting point, the edges in the Delaunay triangulation are screened by the alpha-shape principle to extract the boundary contour fitting the real shape of the discrete point set to obtain a closed region, and interpolation is only performed in the closed region; For the data in which the discrete ray landing point energy is distributed in a closed annular shape around the transmitting point, for a group of rays at each azimuth angle, the nearest landing point to the transmitting point is found out, and the nearest landing points to the transmitting point of all azimuth angles are found out to obtain an inner ring boundary, a closed inner boundary curve is fitted according to the landing points of the inner boundary, the closed region is subjected to mask processing, and after interpolation, the points of the mask are set to be empty, and only the energy interpolation result outside the closed region is reserved.

2. The method of claim 1, wherein, The method further comprises the following steps: Under the selected simulation scenario, a short wave antenna is erected, and the antenna erection position and posture are determined according to the three-dimensional space coordinates and the tilt angle; The gain matrix of the antenna is calculated and generated according to the elevation angle and the azimuth angle which change at equal steps.

3. The method of claim 1, wherein, Based on an ionospheric empirical model, a three-dimensional ionospheric plasma grid and a collision frequency grid are generated around the transmitting point, and the dimensions of the grid include longitude, latitude and height, wherein the height of the three-dimensional grid is the range where the ionosphere is located, and the longitude and latitude range of the three-dimensional grid is estimated according to the great circle distance of short wave propagation.

4. The method of claim 1, wherein, After obtaining the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss, the following steps are further included: The obtained propagation path and ionospheric absorption loss are stored according to the elevation angle and the azimuth angle.

5. The method of claim 1, wherein, The rays with landing points and the positions of the landing points are found out, including the following steps: During the ray tracing process, all rays with effective landing points are marked as 1, and if a ray escapes or terminates at a high altitude at the top layer of the ionosphere, it is marked as -2 or -3; The marks of all rays are scanned, and if a ray marked as 1 is encountered, the landing point position of the ray and the corresponding propagation path, ionospheric absorption loss of the electromagnetic wave signal on the ray are screened out as the basic data source for subsequent landing area energy superposition and interpolation analysis.

6. The method of claim 5, wherein, The total loss of the electromagnetic wave in the ionospheric propagation process is calculated, including the following steps: ， Wherein, Li is ionospheric absorption loss, Yp is ionospheric additional system loss, La is ground scattering loss, Lps is free space transmission loss, ， Wherein, f is frequency, p is electromagnetic wave propagation path length.

7. The method of claim 6, wherein, The falling area energy E of the ray with falling point is calculated as: ， Wherein, Pt is transmitting power, L is total loss, G1 is antenna gain; the direction of antenna gain G1 is consistent with the transmitting direction of the ray, which is indexed and matched by elevation angle and azimuth angle.

8. The method of claim 1, wherein, The calculated falling area energy is interpolated, including: The bilinear interpolation algorithm is adopted to perform bilinear interpolation on the calculated falling area energy, so as to convert the discrete, limited number of ray falling point energy values into continuous, visualized and analyzable area coverage map.

9. A short-wave over-the-horizon communication integrated analog analysis system, characterized in that, Including: The first main module is used for simulating the radiation characteristics of the antenna at a selected frequency in the short wave frequency band, and generating a gain matrix according to the elevation angle and the azimuth angle; The second main module is used for generating a three-dimensional ionospheric plasma grid and a collision frequency grid around the transmitting point based on an ionospheric empirical model, and constructing an ionospheric channel model; The third main module is used for transmitting an electromagnetic wave signal of the selected frequency at the transmitting point according to the elevation angle and the azimuth angle; The fourth main module is used for simulating the propagation process of the electromagnetic wave signal in the ionosphere based on the constructed ionospheric channel model and combining the numerical ray tracing method, so as to obtain the propagation path of the electromagnetic wave signal in the ionosphere and the corresponding ionospheric absorption loss; The fifth main module is used for finding out the ray with falling point and the position of the falling point according to the ray tracing simulation result, and calculating the total loss of the electromagnetic wave in the ionospheric propagation process; The sixth main module is used for calculating the falling area energy of the ray with falling point in combination with the antenna gain and the ray tracing simulation result; The seventh main module is used for interpolating the calculated falling area energy, so as to realize comprehensive analysis on the reachable range of the short wave over-the-horizon communication; wherein, for the interpolation result which is erroneously expanded towards the center, the following mask processing is performed on the center void: For the data in which the discrete ray falling point energy is distributed in a non-closed annular shape around the transmitting point, the edges in the Delaunay triangulation are screened through the alpha-shape principle, the boundary contour which fits the real shape of the scattered point set is extracted, and a closed region is obtained, and the interpolation is only performed in the closed region; For the data in which the discrete ray falling point energy is distributed in a closed annular shape around the transmitting point, the nearest falling point of each group of rays of each azimuth angle is found out, and the nearest falling points of all azimuth angles are found out to obtain the inner ring boundary, a closed inner boundary curve is fitted for the falling points of the inner boundary, the mask processing is performed on the closed region, and after the interpolation, the points of the mask are set to be null, and only the energy interpolation results outside the closed region are reserved.

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