Short-wave communication frequency selection method and device based on ionized layer oblique return detection

Abstract

The invention relates to a short-wave communication frequency selection method and device based on ionosphere slant return detection, and the method comprises the steps: carrying out the slant return detection through employing an ionosphere detection system, obtaining a slant return ionogram, separating a vertical measurement echo and a slant return wave from the ionogram through a mode recognition method, and carrying out the frequency selection of the vertical measurement echo and the slant return wave. The method comprises the following steps: reading local ionosphere parameter information from vertical measurement echoes, tracing a front edge of an oblique return wave, then carrying out ionogram inversion, carrying out data fusion on the local ionosphere parameter information and an inversion result, reconstructing a reflection region ionosphere model, constructing a two-dimensional electron concentration profile, and calculating a corresponding passable frequency range by using a ray tracing method. And finally, selecting an optimal communication frequency point according to signal-to-noise ratio information reflected by the ionogram. Therefore, the problems that an existing short-wave communication frequency selection method does not consider ionosphere factors having important influences on short-wave transmission and frequency selection coordination between users, the frequency selection accuracy and reliability are poor, and the stability is insufficient are solved.

Description

Technical Field

[0001] The present application relates to the technical field of ionospheric detection, and in particular to a shortwave communication frequency selection method and device based on ionospheric oblique return detection. Background Art

[0002] Shortwave communication is an important form of radio communication. After being transmitted, the radio waves are reflected by the ionosphere and reach the receiving device. The communication distance is long, and it is also the only long-distance communication method that is not restricted by active relay systems. Shortwave communication can cover the entire world through multiple reflections from the ionosphere, including special areas such as mountainous areas, deserts, and oceans that cannot be covered by ultra-short waves. Shortwave communication does not require the use of satellites, and the cost of construction and maintenance is low. It has strong flexibility, anti-destruction and stability.

[0003] The ionosphere is a highly dependent channel for shortwave communications, and its dispersion and time-varying properties will affect the effectiveness of shortwave communications. Since the state of the ionosphere is greatly affected by solar activity and seasonal changes, and abnormal states occur frequently, in the practice of shortwave real-time communications, it is necessary to switch different communication frequencies on the spot according to the state of the ionosphere to ensure the quality and stability of shortwave communications.

[0004] At present, although the autonomous frequency selection technology used in shortwave communication integrates spectrum sensing technology and historical communication data, it does not take into account the ionospheric factors that have an important impact on shortwave transmission, but only performs real-time frequency selection based on noise and historical experience data; in addition, the existing autonomous frequency selection does not take into account the frequency selection coordination between users, and may face frequency selection conflicts when conducting regional networking, especially in small areas. The frequency selection performance may decline, and encounter problems such as electromagnetic interference and location exposure, and the stability is insufficient.

[0005] In summary, the existing shortwave communication frequency selection method does not take into account the ionospheric factors that have an important impact on shortwave transmission and the frequency selection coordination between users. The accuracy and reliability of frequency selection are poor, and the stability is insufficient, which needs to be solved urgently. Summary of the invention

[0006] The present application provides a shortwave communication frequency selection method and device based on ionospheric oblique return detection, so as to solve the problems that the existing shortwave communication frequency selection method does not take into account the ionospheric factors that have an important impact on shortwave transmission and the frequency selection coordination between users, and the accuracy and reliability of frequency selection are poor, and the stability is insufficient.

[0007] The first aspect of the present application provides a shortwave communication frequency selection method based on ionospheric oblique return detection, comprising the following steps: obtaining the geographic coordinates of a target mobile station, and determining the great circle distance between the target mobile station and a main base station according to the geographic coordinates, so as to establish an initial ionospheric model through a link corresponding to the great circle distance; performing an oblique return sweep detection operation through an ionospheric detector of the main base station to obtain an oblique return ionogram, and performing echo separation on the oblique return ionogram to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, and extracting local ionospheric parameters from the vertical echo, and performing leading edge detection on the oblique return wave. Tracing to obtain the oblique return wave front tracing result; based on the initial ionosphere model, performing ionosphere parameter inversion on the oblique return wave front tracing result to obtain an inversion result, and using the local ionosphere parameter to constrain the inversion result to reconstruct the reflection zone ionosphere model, and constructing a two-dimensional electron concentration profile through the reflection zone ionosphere model; calculating the passable frequency range between the target mobile station and the main base station according to the two-dimensional electron concentration profile, and obtaining the signal-to-noise ratio characteristics corresponding to the oblique return ionogram, and determining the target communication frequency using the signal-to-noise ratio characteristics, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency.

[0008] Optionally, in one embodiment of the present application, the ionospheric detector of the main base station performs an oblique return frequency sweep detection operation to obtain an oblique return ionogram, and performs echo separation on the oblique return ionogram to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, including: determining a starting frequency, an ending frequency and a stepping frequency of a frequency sweep modulation signal according to different ionospheric states, and generating a target frequency sweep modulation signal through the starting frequency, the ending frequency and the stepping frequency, so as to transmit the target frequency sweep modulation signal through the main base station using a surrounding antenna; receiving an oblique return echo signal corresponding to the target frequency sweep modulation signal, and performing data processing on the oblique return echo signal to generate the oblique return ionogram; constructing an ionogram echo training data set, and training a pre-constructed ionogram echo recognition model through the ionogram echo training data set, and performing pattern recognition on the oblique return ionogram using the trained ionogram echo recognition model to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram.

[0009] Optionally, in one embodiment of the present application, the ionospheric parameter inversion is performed on the oblique return wave front tracing result based on the initial ionospheric model to obtain the inversion result, including: fitting the oblique return wave front tracing result based on an exponential function, a cubic polynomial function and a linear function to obtain fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function respectively; judging whether the fitting curve meets the preset incremental requirement within the target frequency range, wherein if the fitting curve meets the preset incremental requirement, then calculating the root mean square error and the self-correction of the fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function. The R-square is adjusted by the degree of freedom; the target fitting method is determined according to the root mean square error and the degree of freedom adjusted R-square; the search space of the critical frequency, peak height and half thickness of the parameters of the initial ionosphere model is determined by the initial ionosphere model and the target fitting method; a target front tracing set is calculated in the search space, and the target front tracing set is compared with the oblique return wave front tracing result to obtain a comparison result; based on the comparison result and a hybrid genetic algorithm, the ionosphere parameters of the search space of the parameter critical frequency, the peak height and the half thickness are determined when the preset matching requirements are met, and the ionosphere parameters are used as the inversion results.

[0010] Optionally, in one embodiment of the present application, the method of calculating the communicable frequency range between the target mobile station and the main base station based on the two-dimensional electron concentration profile, obtaining the signal-to-noise ratio characteristics corresponding to the oblique return ionization map, and determining the target communication frequency using the signal-to-noise ratio characteristics includes: calculating the electron concentration distribution according to the inversion result and a preset ionospheric quasi-parabolic model, and solving a preset Haselgrove ordinary differential equation group based on a preset numerical ray tracing strategy to obtain a radio wave propagation trajectory diagram; calculating the radio wave propagation trajectory diagram and the electron concentration distribution based on the target mobile station and the main base station. a passable frequency range between; obtaining a signal-to-noise ratio feature corresponding to the oblique return ionogram, and determining the energy distribution of the oblique return wave according to the signal-to-noise ratio feature; based on the energy distribution, calculating the wave propagation group distance corresponding to the great circle distance, and searching the oblique return ionogram for at least one frequency value with a larger signal-to-noise ratio at the corresponding wave group distance according to a preset search frequency range, and using the at least one frequency value as the target communication frequency, wherein the minimum value of the search frequency range is the F2 layer critical frequency in the local ionosphere parameters, and the maximum value of the search frequency range is the maximum passable frequency value of the passable frequency range.

[0011] The second aspect of the present application provides a shortwave communication frequency selection device based on ionospheric oblique return detection, including: a modeling module, used to obtain the geographic coordinates of a target mobile station, and determine the great circle distance between the target mobile station and a main base station according to the geographic coordinates, so as to establish an initial ionospheric model through a link corresponding to the great circle distance; a detection module, used to perform an oblique return sweep detection operation through an ionospheric detector of the main base station, obtain an oblique return ionogram, and perform echo separation on the oblique return ionogram to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, and extract local ionospheric parameters from the vertical echo, and perform front tracing on the oblique return wave. , to obtain the oblique return wave front tracing result; an inversion module, used to perform ionospheric parameter inversion on the oblique return wave front tracing result based on the initial ionospheric model to obtain an inversion result, and use the local ionospheric parameters to constrain the inversion result to reconstruct the reflection zone ionosphere model, and construct a two-dimensional electron concentration profile through the reflection zone ionosphere model; a frequency selection module, used to calculate the passable frequency range between the target mobile station and the main base station according to the two-dimensional electron concentration profile, and obtain the signal-to-noise ratio characteristics corresponding to the oblique return ionogram, and use the signal-to-noise ratio characteristics to determine the target communication frequency, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency.

[0012] Optionally, in one embodiment of the present application, the separation module includes: a transmitting unit, used to determine the starting frequency, the ending frequency and the stepping frequency of the swept frequency modulation signal according to different ionospheric states, and generate a target swept frequency modulation signal through the starting frequency, the ending frequency and the stepping frequency, so as to transmit the target swept frequency modulation signal through the main base station using a surrounding antenna; a receiving unit, used to receive the oblique return echo signal corresponding to the target swept frequency modulation signal, and perform data processing on the oblique return echo signal to generate the oblique return ionization map; an echo separation unit, used to construct an ionization map echo training data set, and train a pre-constructed ionization map echo recognition model through the ionization map echo training data set, and use the trained ionization map echo recognition model to perform pattern recognition on the oblique return ionization map to obtain the vertical echo and oblique return wave corresponding to the oblique return ionization map.

[0013] Optionally, in one embodiment of the present application, the inversion module includes: a fitting unit, which is used to fit the oblique return wave front tracing result based on an exponential function, a cubic polynomial function and a linear function, and obtain fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function respectively; a judgment unit, which is used to judge whether the fitting curve meets the preset incremental requirement within the target frequency range, wherein if the fitting curve meets the preset incremental requirement, the root mean square error and the degree of freedom adjusted R square of the fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function are calculated; a first determination unit, which is used to determine the root mean square error and the degree of freedom adjusted R square according to the root mean square error and the linear function. The degree of freedom is adjusted R square to determine the target fitting method; a second determination unit is used to determine the parameter critical frequency, peak height, and half-thickness search space of the initial ionosphere model through the initial ionosphere model and the target fitting method; a comparison unit is used to calculate a target front tracing set in the search space, and compare the target front tracing set with the oblique return wave front tracing result to obtain a comparison result; a third determination unit is used to determine the ionosphere parameters of the parameter critical frequency, the peak height, and the half-thickness search space when the preset matching requirements are met based on the comparison result and a hybrid genetic algorithm, and use the ionosphere parameters as the inversion result.

[0014] Optionally, in one embodiment of the present application, the frequency selection module includes: a first calculation unit, used to calculate the electron concentration distribution according to the inversion result and the preset ionospheric quasi-parabolic model, and solve the preset Haselgrove ordinary differential equations based on the preset numerical ray tracing strategy to obtain the radio wave propagation trajectory diagram; a second calculation unit, used to calculate the passable frequency range between the target mobile station and the main base station based on the radio wave propagation trajectory diagram and the electron concentration distribution; an acquisition unit, used to obtain the signal-to-noise ratio characteristics corresponding to the oblique return ionization diagram, and determine the energy distribution of the oblique return wave according to the signal-to-noise ratio characteristics; a search unit, used to calculate the radio wave propagation group distance corresponding to the great circle distance based on the energy distribution, and search for at least one frequency value with a larger signal-to-noise ratio at the corresponding radio wave group distance in the oblique return ionization diagram according to the preset search frequency range, and use the at least one frequency value as the target communication frequency, wherein the minimum value of the search frequency range is the F2 layer critical frequency in the local ionosphere parameters, and the maximum value of the search frequency range is the maximum passable frequency of the passable frequency range.

[0015] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the shortwave communication frequency selection method based on ionospheric oblique return detection as described in the above embodiment.

[0016] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the shortwave communication frequency selection method based on ionospheric oblique return detection as described above.

[0017] The fifth aspect embodiment of the present application provides a computer program product, including a computer program, which is executed to implement the above-mentioned shortwave communication frequency selection method based on ionospheric oblique return detection.

[0018] Therefore, the embodiments of the present application have the following beneficial effects:

[0019] The embodiment of the present application can use the ionospheric detection system to perform oblique return detection, obtain the oblique return ionogram, separate the vertical echo and the oblique return wave from the ionogram by the pattern recognition method, read the local ionospheric parameter information from the vertical echo, trace the front of the oblique return wave, then perform ionogram inversion, fuse the local ionospheric parameter information with the inversion result, reconstruct the ionospheric model of the reflection area, construct a two-dimensional electron concentration profile, use the ray tracing method to calculate the corresponding passable frequency range, and finally select the optimal communication frequency point according to the signal-to-noise ratio information reflected in the ionogram. When performing frequency selection, the present application introduces real-time ionospheric detection data and integrates environmental monitoring data, thereby further improving the accuracy and reliability of frequency selection. At the same time, the present application only needs a single station to perform detection, which reduces the cost and workload, improves efficiency, and has important significance and application prospects for the stability of communication between users of both parties. Therefore, the existing shortwave communication frequency selection method does not take into account the ionospheric factors that have an important impact on shortwave transmission and the frequency selection coordination between users, and the accuracy and reliability of frequency selection are poor, and the stability is insufficient.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] Figure 1 A flowchart of a shortwave communication frequency selection method based on ionospheric oblique return detection provided according to an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the logical architecture of a shortwave communication frequency selection method based on ionospheric oblique return detection provided for one embodiment of the present application;

[0024] Figure 3 A schematic diagram of the execution logic of a shortwave communication frequency selection method based on ionospheric oblique return detection provided in one embodiment of the present application;

[0025] Figure 4 (a) is a schematic diagram of an ionospheric oblique return ionogram result provided by an embodiment of the present application;

[0026] Figure 4 (b) is a schematic diagram of vertical echo separation based on pattern recognition provided by an embodiment of the present application;

[0027] Figure 4 (c) is a schematic diagram of a pure oblique return wave result separated by pattern recognition provided by an embodiment of the present application;

[0028] Figure 4 (d) is a schematic diagram of a frontier tracing extraction result of an oblique return wave provided by an embodiment of the present application;

[0029] Figure 5 A schematic diagram of the results of fitting and extending an oblique return wave by three fitting methods provided in one embodiment of the present application;

[0030] Figure 6 A schematic diagram of a two-dimensional electron concentration distribution of a link and a ray tracing result constructed by inverting an ionization diagram provided in an embodiment of the present application;

[0031] Figure 7 A schematic diagram of pD transformation obtained by ionospheric inversion is provided for one embodiment of the present application;

[0032] Figure 8 A schematic diagram of an optimal frequency result provided for an embodiment of the present application;

[0033] Fig. 9 An oblique ionogram obtained by oblique detection of the ionosphere is provided in one embodiment of the present application;

[0034] Fig.10 This is an example diagram of a shortwave communication frequency selection device based on ionospheric oblique return detection according to an embodiment of the present application;

[0035] Fig.11 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0036] Among them, 10-a shortwave communication frequency selection device based on ionospheric oblique return detection; 100-a modeling module, 200-a detection module, 300-an inversion module, 400-a frequency selection module; 1101-a memory, 1102-a processor, 1103-a communication interface. DETAILED DESCRIPTION

[0037] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0038] The following describes the shortwave communication frequency selection method and device based on ionospheric oblique return detection of the embodiment of the present application with reference to the accompanying drawings. In view of the problems mentioned in the above background technology, the present application provides a shortwave communication frequency selection method based on ionospheric oblique return detection, in which an oblique return ionogram is obtained by using an ionospheric detection system to perform oblique return detection, and a vertical echo and an oblique return wave are separated from the ionogram by a pattern recognition method, and local ionospheric parameter information is read from the vertical echo, and the oblique return wave front is traced, and then the ionogram is inverted, and the local ionospheric parameter information is fused with the inversion result, and the reflection zone ionosphere model is reconstructed, and a two-dimensional electron concentration profile is constructed. The corresponding passable frequency range is calculated using a ray tracing method, and finally the optimal communication frequency point is selected according to the signal-to-noise ratio information reflected in the ionogram. This application introduces real-time ionospheric detection data and integrates environmental monitoring data when performing frequency selection, thereby further improving the accuracy and reliability of frequency selection. At the same time, this application only requires a single station for detection, reducing costs and workload, improving efficiency, and having important significance and application prospects for the stability of communication between users of both parties. Thus, the existing shortwave communication frequency selection method does not take into account the ionospheric factors that have an important impact on shortwave transmission and the frequency selection coordination between users, and the frequency selection accuracy and reliability are poor, and the stability is insufficient.

[0039] Specifically, Figure 1 A flow chart of a shortwave communication frequency selection method based on ionospheric oblique return detection provided in an embodiment of the present application.

[0040] like Figure 1 As shown, the shortwave communication frequency selection method based on ionospheric oblique return detection comprises the following steps:

[0041] In step S101, the geographic coordinates of the target mobile station are obtained, and the great circle distance between the target mobile station and the master base station is determined according to the geographic coordinates, so as to establish an initial ionospheric model through a link corresponding to the great circle distance.

[0042] The embodiment of the present application first needs to know the geographical coordinates of the mobile station for establishing the link and the station for establishing the master base station, as well as the great circle distance D between the two stations, and use the ionospheric model statistical data to establish an initial ionospheric background model (i.e., initial ionospheric model) above the link;

[0043] It should be noted that in the embodiments of the present application, the positions of the two stations can be represented by geographic longitude and latitude coordinates, and the great circle distance D between the two points can be calculated by the geographic coordinates, wherein one station is used as a detection signal transmitting station (i.e., the main base station) to transmit ionospheric detection signals and receive ionospheric oblique return detection echoes.

[0044] In addition, the embodiment of the present application can use the International Reference Ionosphere (IRI) model to construct an initial ionospheric background model, that is, by calling the IRI model, inputting the geographic longitude, geographic latitude range, altitude range, and time information, the distribution law of ionospheric parameters such as the ionospheric critical frequency, peak height, and half thickness of the link between the two stations with different great circle distances, as well as the distribution of electron concentration in space are obtained.

[0045] Therefore, the embodiments of the present application obtain the geographic coordinates of the transmitting station and the receiving station (i.e., the target mobile station) and use the ionospheric model statistical data to establish the initial ionospheric background model above the link, thereby providing reliable data support for the construction of subsequent oblique return ionograms and the execution of ionospheric parameter inversion operations.

[0046] In step S102, an oblique return frequency sweep detection operation is performed by the ionospheric detector of the main base station to obtain an oblique return ionogram, and the oblique return ionogram is echo separated to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, and local ionospheric parameters are extracted from the vertical echo, and the oblique return wave is traced at the front to obtain an oblique return wave front tracing result.

[0047] Furthermore, the embodiments of the present application can utilize the ionospheric sounder of the transmitting station to perform oblique return frequency sweep detection to obtain the oblique return ionogram of the ionosphere, and use the pattern recognition method to perform echo separation on the oblique return ionogram to obtain the vertical measurement echo and the oblique return wave corresponding to the oblique return ionogram, such as Figure 2 As shown, the local ionospheric parameters are extracted from the vertical echo, and the front tracing of the oblique return wave is performed to obtain the front tracing result of the oblique return wave.

[0048] Optionally, in one embodiment of the present application, an oblique return frequency sweep detection operation is performed by an ionospheric detector of a main base station to obtain an oblique return ionization map, and the oblique return ionization map is echo separated to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionization map, including: determining a starting frequency, an ending frequency and a stepping frequency of a frequency sweep modulation signal according to different ionospheric states, and generating a target frequency sweep modulation signal by using the starting frequency, the ending frequency and the stepping frequency, so as to transmit the target frequency sweep modulation signal by using a surrounding antenna through the main base station; receiving an oblique return echo signal corresponding to the target frequency sweep modulation signal, and performing data processing on the oblique return echo signal to generate an oblique return ionization map; constructing an ionization map echo training data set, and training a pre-constructed ionization map echo recognition model by using the ionization map echo training data set, and performing pattern recognition on the oblique return ionization map by using the trained ionization map echo recognition model to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionization map.

[0049] In an embodiment of the present application, the ionospheric detector of the transmitting station can be used to perform oblique return frequency scanning detection to obtain an ionospheric oblique return ionogram, and the ionogram echo can be separated by a pattern recognition method to extract local ionospheric parameters from the vertical measurement echo, and the oblique return wave can be traced at the front.

[0050] It should be noted that the embodiments of the present application set the starting frequency, ending frequency, and step frequency of the frequency sweep according to different ionospheric states, so that the transmitting station can use the circular antenna to transmit the m-sequence frequency sweep modulation signal, and use the two-wire dipole antenna at the same location to receive the oblique return echo signal, and draw the oblique return detection ionization map by performing data processing on the received signal.

[0051] It can be understood that, since the transmitting antenna lobe used in oblique return detection is relatively wide, part of the transmitted signal energy may be emitted toward the zenith, so that the detected ionization map not only includes oblique return waves, but also vertical echoes. Therefore, the embodiments of the present application can use pattern recognition methods to separate echoes, thereby obtaining purer vertical echoes and oblique return waves, and perform subsequent processing.

[0052] As a feasible method, the pattern recognition method in the embodiment of the present application can adopt a machine learning model. Specifically, the embodiment of the present application can first construct an ionogram echo training data set, annotate the historical ionogram echoes, and divide them into two types of label values, "Vertical" and "Backscatter", which correspond to vertical echoes and oblique return waves, respectively. The ionogram echo training data set is used to train a pre-constructed ionogram echo recognition model (such as a YOLO model, etc.) to perform pattern recognition and separate the two types of echoes in the detected oblique return ionogram. In addition, the embodiment of the present application can obtain the local ionosphere F2 layer critical frequency foF2 from the extracted relatively pure vertical echo, and obtain the local ionosphere F2 layer peak height hmF2 value according to the empirical formula of the F2 layer peak height, as shown in formula (1).

[0053] hmF2=h(foF2×0.83)(1)

[0054] Afterwards, the embodiment of the present application outlines the echo bottom of the extracted relatively pure oblique return wave, thereby obtaining the oblique return wave front tracing result.

[0055] Therefore, the embodiments of the present application can introduce the ionospheric factor, which is highly dependent on shortwave communication, into the frequency selection, and provide different communication frequencies in real time according to the changes in the ionospheric state, thereby further improving the accuracy and stability of the frequency selection and meeting the regional networking requirements.

[0056] In step S103, based on the initial ionospheric model, the ionospheric parameters are inverted for the oblique return wave front tracing results to obtain the inversion results, and the inversion results are constrained by local ionospheric parameters to reconstruct the ionospheric model of the reflection area, and a two-dimensional electron concentration profile is constructed through the ionospheric model of the reflection area.

[0057] Furthermore, the embodiments of the present application use the initial ionospheric model as the initial value, use the ionogram inversion technology to invert the ionospheric parameters of the oblique return wave front tracing results, and use the detection results and the inversion results to perform data fusion to reconstruct the ionospheric model of the reflection area, and calculate the two-dimensional information of the ionospheric electron concentration with respect to the ground great circle distance and altitude, so as to comprehensively describe the ionospheric situation in the reflection area.

[0058] Optionally, in one embodiment of the present application, based on the initial ionospheric model, the ionospheric parameter inversion is performed on the oblique return wave front tracing result to obtain the inversion result, including: fitting the oblique return wave front tracing result based on the exponential function, the cubic polynomial function and the linear function, and obtaining the fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function respectively; judging whether the fitting curve meets the preset incremental requirement within the target frequency range, wherein if the fitting curve meets the preset incremental requirement, then calculating the root mean square error and the square root error of the fitting curve corresponding to the exponential function, the cubic polynomial function and the linear function. The degrees of freedom are adjusted to R square; the target fitting method is determined according to the root mean square error and the degrees of freedom adjusted R square; the search space of the critical frequency, peak height and half thickness of the parameters of the initial ionosphere model is determined by the initial ionosphere model and the target fitting method; the target front tracing set is calculated in the search space, and the target front tracing set is compared with the oblique return wave front tracing result to obtain the comparison result; based on the comparison result and the hybrid genetic algorithm, the ionosphere parameters of the search space of the critical frequency, peak height and half thickness of the parameters are determined when the preset matching requirements are met, and the ionosphere parameters are used as the inversion results.

[0059] It should be noted that the embodiments of the present application can use the ionospheric quasi-parabolic (QP) model to describe the electron concentration distribution and perform the inversion of the ionization diagram. The mathematical expression of the QP model is as follows:

[0060]

[0061] Among them, N m is the maximum value of the corresponding ionospheric electron concentration. The general calculation method is N m =f c 2 / 80.6;f c It is the critical frequency shown in the ionospheric frequency diagram, generally calculated with o-wave; r m Indicates the maximum electron concentration N m The height at which it is located, referred to as peak height; r b Indicates the height of the bottom of the ionosphere; y m Represents the half thickness of the ionospheric electron concentration profile, calculated as y m =r m -r b .

[0062] In the actual implementation process, for the oblique return front trace, in order to invert the ionospheric parameters at a longer distance, the embodiment of the present application can fit and extend the front, and select three fitting methods, namely exponential function, cubic polynomial function and linear function, according to different situations, to determine whether the three fitting curves increase consistently in the frequency range, and calculate the degrees of freedom adjusted R square and relative root mean square error of the three fitting curves. After quantitative comparison, a relatively better fitting method is selected, and the root mean square error (RMSE) and the degrees of freedom adjusted R square R 2 The calculation method of (adj) is as follows:

[0063]

[0064] in, It represents the difference between the true value and the fitted value; represents the difference between the true value and its average value; n represents the number of samples; p represents the number of variables; in the embodiment of the present application, R 2 The larger the (adj), the better the fitting effect.

[0065] In the process of inverting the frontier trace, the embodiment of the present application can first select several points from the extracted frontier trace, and according to the set ionosphere initial model, set the search space of the model's parameter critical frequency foF2, peak height hmF2, and half thickness ymF2, and find the parameter group (i.e., the target inversion parameter group) that can achieve the best inversion effect within the corresponding parameter range through a hybrid genetic algorithm, and use it as the inversion result, and at the same time use the local ionosphere parameter information extracted from the vertical echo to constrain the inversion result.

[0066] Therefore, when performing frequency selection, the embodiments of the present application take into account the ionospheric factors that have an important impact on shortwave communications, introduce real-time ionospheric detection data, and integrate environmental monitoring data to further improve the accuracy and reliability of frequency selection, thereby enriching the research content in the field of data fusion, and serving as an attempt and exploration for frequency selection by integrating multiple influencing factors such as ionospheric detection data and environmental monitoring data in the field of shortwave communications.

[0067] In step S104, the passable frequency range between the target mobile station and the main base station is calculated based on the two-dimensional electron concentration profile, and the signal-to-noise ratio characteristics corresponding to the oblique return ionization diagram are obtained, and the target communication frequency is determined using the signal-to-noise ratio characteristics, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency.

[0068] Afterwards, the embodiments of the present application can calculate the passable frequency range of the distance D between the two stations based on the two-dimensional electron concentration profile and use ray tracing technology, and select the optimal communication frequency (i.e., the target communication frequency) based on the energy distribution of the oblique return detection echo, thereby constructing a recommended communication frequency group through the passable frequency range and the target communication frequency.

[0069] Therefore, in the embodiment of the present application, when selecting a frequency, only a single station is required to perform detection, and there is no need for collaborative detection between two stations, thereby reducing costs and workload and improving efficiency.

[0070] Optionally, in one embodiment of the present application, the accessible frequency range between the target mobile station and the main base station is calculated according to the two-dimensional electron concentration profile, and the signal-to-noise ratio characteristics corresponding to the oblique return ionization map are obtained, and the target communication frequency is determined using the signal-to-noise ratio characteristics, including: calculating the electron concentration distribution according to the inversion result and the preset ionospheric quasi-parabolic model, and solving the preset Haselgrove ordinary differential equations based on the preset numerical ray tracing strategy to obtain the radio wave propagation trajectory diagram; calculating the target mobile station and the main base station based on the radio wave propagation trajectory diagram and the electron concentration distribution. The communication frequency range between the stations is obtained; the signal-to-noise ratio characteristics corresponding to the oblique return ionogram are obtained, and the energy distribution of the oblique return wave is determined according to the signal-to-noise ratio characteristics; based on the energy distribution, the wave propagation group distance corresponding to the great circle distance is calculated, and at least one frequency value with a large signal-to-noise ratio at the corresponding wave group distance is searched in the oblique return ionogram according to a preset search frequency range, and at least one frequency value is used as the target communication frequency, wherein the minimum value of the search frequency range is the critical frequency of the F2 layer in the local ionosphere parameters, and the maximum value of the search frequency range is the maximum value of the passable frequency in the passable frequency range.

[0071] In the specific implementation process, the embodiments of the present application can obtain the great circle distance D between two communicating stations through the relative geographic coordinate relationship, and can solve the Haselgrove ordinary differential equations through the numerical ray tracing technology in the ray tracing technology to obtain the radio wave propagation trajectory diagram, thereby finding the regular relationship between the ionospheric electron concentration and the signal propagation group path, ground distance, elevation angle, frequency, etc., and finally obtain the passable frequency range at the corresponding distance.

[0072] It should be noted that, in the embodiments of the present application, the energy distribution of the oblique return detection echo can be reflected by the echo signal-to-noise ratio in the oblique return ionization map. The embodiments of the present application can obtain the radio wave group distance p corresponding to D through ionospheric inversion based on the great circle distance D between the two stations, and then search for several frequency values ​​with a large signal-to-noise ratio at the corresponding group distance in the ionization map, and use it as the selected optimal communication frequency.

[0073] As an achievable method, the embodiment of the present application can use the pD transformation technology, and obtain the corresponding radio wave group distance p according to the great circle distance D. In the ionospheric single-layer QP model, the relationship between the group distance p of the ray with a frequency of f and an elevation angle of α and the ground great circle distance D between the ray receiving point and the transmitting point can be directly obtained through ionospheric inversion, wherein the relationship between the group distance p and the great circle distance D is as follows:

[0074]

[0075] The above parameters A, B, C, F and cosγ are calculated as follows:

[0076]

[0077] Among them, γ is the incident angle of the ray at the bottom of the ionosphere, β is the emission elevation angle of the signal, and r0 is the radius of the earth.

[0078] It should be noted that when searching for the optimal communication frequency within the search frequency range, the embodiment of the present application can first set the maximum value of the search frequency to the maximum value of the passable frequency obtained by ray tracing calculation, and set the minimum value of the frequency search to the F2 layer critical frequency foF2 obtained from the vertical measurement echo, thereby avoiding the situation where the radio waves corresponding to the selected frequency point have multi-mode propagation, thereby better improving the communication effect.

[0079] The following describes the execution logic of the shortwave communication frequency selection method based on ionospheric oblique return detection of the present application in combination with the accompanying drawings.

[0080] Figure 3 The following is a schematic diagram of the execution logic of the shortwave communication frequency selection method based on ionospheric oblique return detection of the present application. Figure 3 As shown, the execution logic of the shortwave communication frequency selection method based on ionospheric oblique return detection of the present application is as follows:

[0081] S301: Obtaining the geographical coordinates of the mobile station and the great circle distance between the mobile station and the main base station;

[0082] S302: Establishing a space ionosphere background model using IRI model statistical data;

[0083] S303: using the ionospheric detector of the main base station to perform oblique return detection;

[0084] S304: using a YOLO model to perform echo separation on the detected ionization image;

[0085] S305: extracting local ionospheric parameters from the separated vertical echo and performing front tracing on the oblique return wave;

[0086] S306: using ionogram inversion technology to perform ionospheric parameter inversion on the oblique return detection data;

[0087] S307: Reconstruct the ionosphere model of the reflection area and construct a two-dimensional electron concentration profile using the inversion results and local ionosphere parameter information;

[0088] S308: Calculate the accessible frequency range between two stations using ray tracing technology;

[0089] S309: Selecting the optimal communication frequency according to the energy distribution and signal-to-noise ratio of the oblique return detection echo;

[0090] S3010: The selected communicable frequency range and optimal communication frequency are used as a recommended communication frequency group.

[0091] The following describes the execution process and execution effect of the shortwave communication frequency selection method based on ionospheric oblique return detection of the present application through specific embodiments and in combination with the accompanying drawings.

[0092] In a specific embodiment of the present application, a conventional ionospheric detection system can be used to transmit an m-sequence frequency-sweeping modulation signal to a circumferential antenna to perform ionospheric oblique return detection and obtain an oblique return ionogram, such as Figure 4 As shown in (a) of Figure 4 From (a) in the figure, we can see that the oblique return ionogram includes two regions: the oblique return wave and the vertical echo. Secondly, the pure oblique return wave and the vertical echo are separated by pattern recognition method, and the local ionospheric parameters are read from the separated vertical echo, such as Figure 4 As shown in (b), the critical frequency foF2 and peak height hmF2 of the local ionosphere F2 layer are obtained respectively. The pure oblique return wave separated by pattern recognition is shown as Figure 4 As shown in (c) in FIG. 1 ; then the separated oblique return wave is subjected to frontier tracing extraction, as shown in FIG. Figure 4 As shown in (d), the thick solid line is the result of frontier tracing.

[0093] like Figure 5 As shown, the specific embodiment of the present application can fit and extend the oblique return wave by three fitting methods. The solid line represents the original oblique return front, the dotted line represents the exponential fitting result, the dotted line represents the cubic function fitting result, and the dash-dotted line represents the linear fitting result. After quantitatively and comprehensively comparing the fitting effects of the three methods, the front fitting result that best conforms to the law of ionospheric changes is selected. In the specific embodiment of the present application, the exponential fitting method has the highest degree of conformity.

[0094] Figure 6 The two-dimensional electron concentration distribution of the constructed link and the ray tracing results are shown after inverting the ionization map. Figure 6As shown, the horizontal axis represents the great circle distance from the Wuhan station, the vertical axis represents the vertical height from the ground, the color depth reflects the size of the electron concentration, the darker the color, the greater the electron concentration in the corresponding area; the search frequency of the ray is 7.0-25.0MHz, the step frequency is 0.5MHz, the elevation angle search range of the ray is 15° to 60°, and the step angle is 5°; Figure 6 This is the ray tracing result corresponding to the ray frequency of 17.5MHz. From the trajectory of the rays, we can see that some rays with higher elevation angles are reflected by the ionosphere and end at a far distance on the ground; some rays with higher elevation angles cannot be reflected by the ionosphere and directly penetrate through it. After traversal, it can be obtained that when the required communication distance on the link is 915km, the passable frequency range is 8.0-19.0MHz.

[0095] The specific embodiment of the present application can obtain the pD transformation schematic diagram through ionospheric inversion, such as Figure 7 As shown, the horizontal axis represents the great circle distance D, and the vertical axis represents the group distance p.

[0096] The schematic result of selecting the optimal frequency in the specific embodiment of this application is as follows Figure 8 As shown by Figure 8 It can be seen that the background of the picture Figure 4 The same as (a) in the figure is the oblique return ionization diagram obtained by detection. The blue horizontal line represents the group distance p corresponding to the great circle distance D, and its value is obtained by pD transformation. Figure 7 At the corresponding group distance obtained in , the three frequency points with the best signal-to-noise ratio are: 17.0MHz, 16.5MHz and 16.2MHz.

[0097] In the specific embodiment of this application, Fig. 9 The oblique ionogram result obtained by oblique ionospheric detection is used to verify the shortwave communication frequency selection method based on ionospheric oblique return detection of the present application; Fig. 9 The maximum available frequency is about 19.0MHz, and Fig. 9 It can be seen that there are oblique echoes in the frequency band from 8.0MHz to 19.0MHz, the frequency range obtained by ray tracing is within this frequency band, and the best communication frequency points selected from the oblique return ionization map are all within the oblique echo range, which proves that the frequency selected using the oblique return map can be used for effective communication.

[0098] According to the shortwave communication frequency selection method based on ionospheric oblique return detection proposed in the embodiment of the present application, an ionospheric detection system is used to perform oblique return detection, an oblique return ionogram is obtained, a vertical echo and an oblique return wave are separated from the ionogram by a pattern recognition method, local ionospheric parameter information is read from the vertical echo, the front edge of the oblique return wave is traced, and then the ionogram is inverted, the local ionospheric parameter information and the inversion result are data-fused, the ionospheric model of the reflection area is reconstructed, a two-dimensional electron concentration profile is constructed, and the corresponding passable frequency range is calculated using a ray tracing method. Finally, the optimal communication frequency point is selected according to the signal-to-noise ratio information reflected in the ionogram. When performing frequency selection, the present application introduces real-time ionospheric detection data and integrates environmental monitoring data, thereby further improving the accuracy and reliability of frequency selection. At the same time, the present application only requires a single station for detection, which reduces costs and workload, improves efficiency, and has important significance and application prospects for the stability of communication between users of both parties.

[0099] Secondly, the shortwave communication frequency selection device based on ionospheric oblique return detection proposed in an embodiment of the present application is described with reference to the accompanying drawings.

[0100] Fig.10 It is a block diagram of a shortwave communication frequency selection device based on ionospheric oblique return detection according to an embodiment of the present application.

[0101] like Fig.10 As shown, the shortwave communication frequency selection device 10 based on ionospheric oblique return detection includes: a modeling module 100, a detection module 200, an inversion module 300 and a frequency selection module 400.

[0102] The modeling module 100 is used to obtain the geographic coordinates of the target mobile station, and determine the great circle distance between the target mobile station and the main base station according to the geographic coordinates, so as to establish an initial ionospheric model through the link corresponding to the great circle distance.

[0103] The detection module 200 is used to perform oblique return frequency sweep detection operation through the ionospheric detector of the main base station, obtain the oblique return ionization map, and perform echo separation on the oblique return ionization map to obtain the vertical echo and oblique return wave corresponding to the oblique return ionization map, and extract the local ionospheric parameters from the vertical echo, and perform front tracing on the oblique return wave to obtain the front tracing result of the oblique return wave.

[0104] The inversion module 300 is used to perform ionospheric parameter inversion on the oblique return wave front tracing result based on the initial ionospheric model to obtain the inversion result, and to constrain the inversion result with the local ionospheric parameter to reconstruct the ionospheric model of the reflection area, and to construct a two-dimensional electron concentration profile through the ionospheric model of the reflection area.

[0105] The frequency selection module 400 is used to calculate the passable frequency range between the target mobile station and the main base station according to the two-dimensional electron concentration profile, and obtain the signal-to-noise ratio characteristics corresponding to the oblique return ionization diagram, and use the signal-to-noise ratio characteristics to determine the target communication frequency, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency.

[0106] Optionally, in one embodiment of the present application, the separation module 200 includes: a transmitting unit, a receiving unit and an echo separation unit.

[0107] Among them, the transmitting unit is used to determine the starting frequency, ending frequency and step frequency of the sweep frequency modulation signal according to different ionospheric states, and generate the target sweep frequency modulation signal through the starting frequency, ending frequency and step frequency, so as to transmit the target sweep frequency modulation signal through the main base station using the surrounding antenna.

[0108] The receiving unit is used to receive the oblique return echo signal corresponding to the target frequency sweep modulation signal, and perform data processing on the oblique return echo signal to generate an oblique return ionization map.

[0109] The echo separation unit is used to construct an ionogram echo training data set, and train a pre-constructed ionogram echo recognition model through the ionogram echo training data set, and use the trained ionogram echo recognition model to perform pattern recognition on the oblique return ionogram to obtain the vertical echo and oblique return wave corresponding to the oblique return ionogram.

[0110] Optionally, in one embodiment of the present application, the inversion module 300 includes: a fitting unit, a judgment unit, a first determination unit, a second determination unit, a comparison unit and a third determination unit.

[0111] Among them, the fitting unit is used to fit the front tracing results of the oblique return wave based on the exponential function, the cubic polynomial function and the linear function, and obtain the fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function respectively.

[0112] A judgment unit is used to judge whether the fitting curve meets the preset incremental requirement within the target frequency range, wherein if the fitting curve meets the preset incremental requirement, the root mean square error and the degree of freedom adjusted R square of the fitting curve corresponding to the exponential function, the cubic polynomial function and the linear function are calculated.

[0113] The first determination unit is used to determine a target fitting mode according to a root mean square error and a degree of freedom adjusted R square.

[0114] The second determination unit is used to determine the search space of the critical frequency, peak height and half thickness of the parameters of the initial ionosphere model through the initial ionosphere model and the target fitting method.

[0115] The comparison unit is used to calculate the target front tracing set in the search space, and compare the target front tracing set with the oblique return wave front tracing result to obtain a comparison result.

[0116] The third determination unit is used to determine the ionospheric parameters of the search space of the parameters critical frequency, peak height and half thickness when the preset matching requirements are met based on the comparison results and the hybrid genetic algorithm, and use the ionospheric parameters as the inversion results.

[0117] Optionally, in one embodiment of the present application, the frequency selection module 400 includes: a first calculation unit, a second calculation unit, an acquisition unit and a search unit.

[0118] Among them, the first calculation unit is used to calculate the electron concentration distribution according to the inversion results and the preset ionospheric quasi-parabolic model, and solve the preset Haselgrove ordinary differential equations based on the preset numerical ray tracing strategy to obtain the radio wave propagation trajectory diagram.

[0119] The second calculation unit is used to calculate the communicable frequency range between the target mobile station and the main base station based on the radio wave propagation trajectory diagram and the electron concentration distribution.

[0120] The acquisition unit is used to acquire the signal-to-noise ratio characteristics corresponding to the oblique return ionization image, and determine the energy distribution of the oblique return wave according to the signal-to-noise ratio characteristics.

[0121] A search unit is used to calculate the radio wave propagation group distance corresponding to the great circle distance based on the energy distribution, and search for at least one frequency value with a larger signal-to-noise ratio at the corresponding radio wave group distance in the oblique return ionogram according to a preset search frequency range, and use at least one frequency value as a target communication frequency, wherein the minimum value of the search frequency range is the F2 layer critical frequency in the local ionosphere parameters, and the maximum value of the search frequency range is the maximum value of the passable frequency in the passable frequency range.

[0122] It should be noted that the aforementioned explanation of the embodiment of the shortwave communication frequency selection method based on ionospheric oblique return detection is also applicable to the shortwave communication frequency selection device based on ionospheric oblique return detection of this embodiment, and will not be repeated here.

[0123] The shortwave communication frequency selection device based on ionospheric oblique return detection proposed in the embodiment of the present application includes a modeling module, which is used to obtain the geographic coordinates of the target mobile station, and determine the great circle distance between the target mobile station and the main base station according to the geographic coordinates, so as to establish an initial ionospheric model through the link corresponding to the great circle distance; a separation module, which is used to perform an oblique return sweep detection operation through the ionospheric detector of the main base station, obtain an oblique return ionogram, and perform echo separation on the oblique return ionogram to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, and extract local ionospheric parameters from the vertical echo, and perform frontier separation on the oblique return wave. Tracing to obtain the tracing result of the oblique return wave front; the inversion module is used to perform ionospheric parameter inversion on the oblique return wave front tracing result based on the initial ionospheric model to obtain the inversion result, and use the local ionospheric parameter to constrain the inversion result to reconstruct the reflection zone ionosphere model, and construct a two-dimensional electron concentration profile through the reflection zone ionosphere model; the frequency selection module is used to calculate the passable frequency range between the target mobile station and the main base station according to the two-dimensional electron concentration profile, and obtain the signal-to-noise ratio characteristics corresponding to the oblique return ionogram, and use the signal-to-noise ratio characteristics to determine the target communication frequency, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency. When performing frequency selection, the present application introduces real-time ionospheric detection data and integrates environmental monitoring data, thereby further improving the accuracy and reliability of frequency selection. At the same time, the present application only requires a single station for detection, which reduces costs and workload, improves efficiency, and has important significance and application prospects for the stability of communication between users of both parties.

[0124] Fig.11 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0125] A memory 1101 , a processor 1102 , and a computer program stored in the memory 1101 and executable on the processor 1102 .

[0126] When the processor 1102 executes the program, the shortwave communication frequency selection method based on ionospheric oblique return detection provided in the above embodiment is implemented.

[0127] Furthermore, the electronic device further comprises:

[0128] The communication interface 1103 is used for communication between the memory 1101 and the processor 1102 .

[0129] The memory 1101 is used to store computer programs that can be executed on the processor 1102 .

[0130] The memory 1101 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0131] If the memory 1101, the processor 1102 and the communication interface 1103 are implemented independently, the communication interface 1103, the memory 1101 and the processor 1102 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.11 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0132] Optionally, in a specific implementation, if the memory 1101, the processor 1102 and the communication interface 1103 are integrated on a chip, the memory 1101, the processor 1102 and the communication interface 1103 can communicate with each other through an internal interface.

[0133] The processor 1102 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0134] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the shortwave communication frequency selection method based on ionospheric oblique return detection as described above.

[0135] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed, is used to implement the above-mentioned shortwave communication frequency selection method based on ionospheric oblique return detection.

[0136] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0137] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0138] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0139] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0140] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0141] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0142] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0143] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A shortwave communication frequency selection method based on ionospheric oblique return detection, characterized in that: The following steps are involved: Acquire the geographic coordinates of the target mobile station, and determine the great circle distance between the target mobile station and the master base station according to the geographic coordinates, so as to establish an initial ionospheric model through a link corresponding to the great circle distance; An oblique return frequency sweep detection operation is performed by the ionospheric sounder of the main base station to obtain an oblique return ionogram, and echo separation is performed on the oblique return ionogram to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, and local ionospheric parameters are extracted from the vertical echo, and a front tracing is performed on the oblique return wave to obtain an oblique return wave front tracing result; Based on the initial ionosphere model, ionosphere parameter inversion is performed on the oblique return wave front tracing result to obtain an inversion result, and the inversion result is constrained by the local ionosphere parameter to reconstruct the reflection area ionosphere model, and a two-dimensional electron concentration profile is constructed through the reflection area ionosphere model; The passable frequency range between the target mobile station and the main base station is calculated according to the two-dimensional electron concentration profile, and the signal-to-noise ratio characteristics corresponding to the oblique return ionization diagram are obtained, and the target communication frequency is determined using the signal-to-noise ratio characteristics, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency.

2. The method according to claim 1, characterized in that: The method of performing an oblique return frequency sweep detection operation through the ionospheric detector of the main base station to obtain an oblique return ionogram, and performing echo separation on the oblique return ionogram to obtain a vertical measurement echo and an oblique return wave corresponding to the oblique return ionogram includes: Determine the starting frequency, ending frequency and step frequency of the sweep frequency modulation signal according to different ionospheric states, and generate a target sweep frequency modulation signal through the starting frequency, ending frequency and step frequency, so as to transmit the target sweep frequency modulation signal through the main base station using the circumferential antenna; receiving an oblique return echo signal corresponding to the target frequency sweep modulation signal, and performing data processing on the oblique return echo signal to generate the oblique return ionization map; An ionogram echo training data set is constructed, and a pre-constructed ionogram echo recognition model is trained by the ionogram echo training data set. The trained ionogram echo recognition model is used to perform pattern recognition on the oblique return ionogram to obtain the vertical echo and the oblique return wave corresponding to the oblique return ionogram.

3. The method according to claim 2, characterized in that The method of performing ionospheric parameter inversion on the oblique return wave front trace result based on the initial ionospheric model to obtain an inversion result includes: Based on an exponential function, a cubic polynomial function and a linear function, the front tracing result of the oblique return wave is fitted to obtain fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function respectively; Determining whether the fitting curve meets a preset incremental requirement within a target frequency range, wherein if the fitting curve meets the preset incremental requirement, calculating the root mean square error and the degree of freedom adjusted R square of the fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function; Determine a target fitting method according to the root mean square error and the degree of freedom adjusted R square; Determine the search space of the critical frequency, peak height and half thickness of the parameters of the initial ionosphere model by using the initial ionosphere model and the target fitting method; Calculating a target front tracing set in the search space, and comparing the target front tracing set with the oblique return wave front tracing result to obtain a comparison result; Based on the comparison result and the hybrid genetic algorithm, the ionospheric parameters of the search space of the parameter critical frequency, the peak height and the half thickness are determined when the preset matching requirements are met, and the ionospheric parameters are used as the inversion results.

4. The method according to claim 3, characterized in that The calculating the communicable frequency range between the target mobile station and the master base station according to the two-dimensional electron concentration profile, obtaining the signal-to-noise ratio feature corresponding to the oblique return ionization diagram, and determining the target communication frequency using the signal-to-noise ratio feature, includes: Calculating the electron concentration distribution according to the inversion result and the preset ionospheric quasi-parabolic model, and solving the preset Haselgrove ordinary differential equations based on the preset numerical ray tracing strategy to obtain a radio wave propagation trajectory diagram; Calculating a communicable frequency range between the target mobile station and the master base station based on the radio wave propagation trajectory diagram and the electron concentration distribution; Acquire a signal-to-noise ratio feature corresponding to the oblique return ionization image, and determine the energy distribution of the oblique return wave according to the signal-to-noise ratio feature; Based on the energy distribution, the radio wave propagation group distance corresponding to the great circle distance is calculated, and at least one frequency value with a larger signal-to-noise ratio at the corresponding radio wave group distance is searched in the oblique return ionogram according to a preset search frequency range, and the at least one frequency value is used as the target communication frequency, wherein the minimum value of the search frequency range is the F2 layer critical frequency in the local ionosphere parameters, and the maximum value of the search frequency range is the maximum value of the passable frequency in the passable frequency range.

5. A shortwave communication frequency selection device based on ionospheric oblique return detection, characterized in that: include: A modeling module, used for acquiring the geographic coordinates of the target mobile station, and determining the great circle distance between the target mobile station and the master base station according to the geographic coordinates, so as to establish an initial ionospheric model through a link corresponding to the great circle distance; A detection module, used for performing an oblique return frequency sweep detection operation through the ionospheric sounder of the main base station to obtain an oblique return ionogram, and performing echo separation on the oblique return ionogram to obtain a vertical echo and an oblique return wave corresponding to the oblique return ionogram, and extracting local ionospheric parameters from the vertical echo, and performing front tracing on the oblique return wave to obtain an oblique return wave front tracing result; An inversion module is used to perform ionospheric parameter inversion on the oblique return wave front tracing result based on the initial ionospheric model to obtain an inversion result, and to constrain the inversion result using the local ionospheric parameter to reconstruct the reflection area ionospheric model, and to construct a two-dimensional electron concentration profile through the reflection area ionospheric model; A frequency selection module is used to calculate the passable frequency range between the target mobile station and the main base station according to the two-dimensional electron concentration profile, and obtain the signal-to-noise ratio characteristics corresponding to the oblique return ionization diagram, and determine the target communication frequency using the signal-to-noise ratio characteristics, so as to construct a recommended communication frequency group through the passable frequency range and the target communication frequency.

6. The device according to claim 5, characterized in that The detection module comprises: A transmitting unit, used for determining the starting frequency, the ending frequency and the stepping frequency of the sweep frequency modulation signal according to different ionospheric states, and generating a target sweep frequency modulation signal through the starting frequency, the ending frequency and the stepping frequency, so as to transmit the target sweep frequency modulation signal through the main base station using the circumferential antenna; A receiving unit, used for receiving an oblique return echo signal corresponding to the target frequency sweep modulation signal, and performing data processing on the oblique return echo signal to generate the oblique return ionization map; The echo separation unit is used to construct an ionogram echo training data set, and train a pre-constructed ionogram echo recognition model through the ionogram echo training data set, and use the trained ionogram echo recognition model to perform pattern recognition on the oblique return ionogram to obtain the vertical echo and oblique return wave corresponding to the oblique return ionogram.

7. The device according to claim 6, characterized in that The inversion module comprises: A fitting unit, used for fitting the oblique return wave front trace result based on an exponential function, a cubic polynomial function and a linear function, to obtain fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function respectively; A judging unit, configured to judge whether the fitting curve satisfies a preset incremental requirement within a target frequency range, wherein if the fitting curve satisfies the preset incremental requirement, a root mean square error and a degree of freedom adjusted R square of the fitting curves corresponding to the exponential function, the cubic polynomial function and the linear function are calculated; A first determining unit, configured to determine a target fitting mode according to the root mean square error and the degree of freedom adjusted R square; A second determining unit is used to determine the search space of the critical frequency, peak height and half thickness of the parameters of the initial ionosphere model through the initial ionosphere model and the target fitting method; A comparison unit, used for calculating a target front tracing set in the search space, and comparing the target front tracing set with the oblique return wave front tracing result to obtain a comparison result; A third determination unit is used to determine the ionospheric parameters of the search space of the parameter critical frequency, the peak height and the half thickness when the preset matching requirements are met based on the comparison result and the hybrid genetic algorithm, and use the ionospheric parameters as the inversion result.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the shortwave communication frequency selection method based on ionospheric oblique return detection as described in any one of claims 1 to 4.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the shortwave communication frequency selection method based on ionospheric oblique return detection as described in any one of claims 1-4.

10. A computer program product, comprising a computer program, characterized in that The computer program is executed to implement the shortwave communication frequency selection method based on ionospheric oblique return detection as described in any one of claims 1-4.

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