A shortwave signal direction finding method and device for irregular sparse array

Abstract

The present invention provides a shortwave signal direction-finding method and device for an irregular sparse array, belonging to the technical field of shortwave communication direction-finding. Addressing the direction-finding ambiguity problem in irregular sparse arrays, the present invention employs an array arrangement of antenna elements with different horizontal and vertical positions, simultaneously eliminating angular ambiguity in both azimuth and elevation. A dual-polarized antenna is used to receive incoming signals for direction-finding, fully utilizing the two polarization components of the shortwave skywave signal to improve direction-finding capability. Peak correlation between the current phase difference vector and expected phase difference vectors in different azimuths is used to determine the direction-finding azimuth angle range, reducing the computational complexity of DOA estimation. Azimuth consistency judgment and DOA spectrum peak size comparison methods are used to fuse the direction-finding results to obtain a correct direction-finding result. This method can effectively resolve the direction-finding ambiguity problem in irregular sparse arrays, improve the direction-finding capability for incoming signals with composite polarization patterns, and achieve both accuracy and real-time performance.

Description

Technical Field

[0001] The present invention relates to the technical field of shortwave communication direction finding, and in particular to a shortwave signal direction finding method and device of an irregular sparse array. Background Art

[0002] Traditional shortwave direction-finding stations typically utilize a uniform circular array layout, which places high demands on the site environment. The spacing between array elements is generally less than half a wavelength. This limits the aperture of the entire array when the number of elements is fixed, thus affecting direction-finding accuracy. Array elements typically utilize vertically polarized antennas, which have limited ability to receive horizontally polarized electromagnetic waves. Irregular sparse arrays utilize a conformal layout, which reduces site requirements. With a sparse array layout, the spacing between antenna elements is greater than half a wavelength, reducing the mutual coupling between antenna elements and increasing the array aperture, enabling higher direction-finding accuracy. Antenna elements utilize both horizontal and vertical polarization, enabling more efficient reception of shortwave signals with a composite polarization pattern after reflection from the ionosphere, thereby improving shortwave direction-finding performance.

[0003] When using an irregular sparse array, the presence of grating lobes and high sidelobes in the array due to the element spacing being greater than half a wavelength. If these grating lobes and high sidelobes are not suppressed, they can cause ambiguity in direction finding and lead to errors. Existing sidelobe suppression methods employ coprime or nested sparse arrays, exploiting the varying horizontal spacing of the elements to resolve direction finding ambiguities. This ambiguity resolution method is limited in effectiveness, only resolving ambiguities in azimuth but not in elevation, making it unsuitable for applications requiring two-dimensional direction finding. Due to the anisotropy of this irregular sparse array, multi-frequency array calibration is required from different azimuths to generate a series of calibration vectors at different azimuths and frequencies. In practical direction finding applications, using these calibration vectors to estimate the direction of arrival of signal (DOA) one by one is computationally intensive and difficult to meet the real-time requirements of direction finding. Furthermore, integrating the series of direction finding results calculated from different calibration vectors to obtain accurate direction finding results is an urgent issue. Summary of the Invention

[0004] The present invention provides a shortwave signal direction finding method and device of an irregular sparse array, which are used to solve the defects in the prior art and improve the direction finding capability of shortwave signals.

[0005] In a first aspect, the present invention provides a shortwave signal direction finding method for an irregular sparse array, comprising: using M antennas of an antenna array to synchronously collect target shortwave signals, obtaining data from M channels, selecting one of the channels as a reference channel, and calculating a current phase difference vector;

[0006] According to the center frequency of the target shortwave signal, N groups of calibration vectors in N directions are selected to determine N groups of expected phase difference vectors in N directions;

[0007] Perform correlation operations on the current phase difference vector and N groups of expected phase difference vectors, and use the azimuth corresponding to the maximum peak as the reference azimuth;

[0008] DOA estimation is performed on each of N1 groups of calibration vectors within a preset range near the reference azimuth, so as to determine a final direction finding result based on the direction finding results of multiple DOA estimations.

[0009] According to a shortwave signal direction-finding method for an irregular sparse array provided by the present invention, N groups of calibration vectors for N azimuths are selected based on the center frequency of the target shortwave signal, and N groups of expected phase difference vectors for the N azimuths are determined. The method includes: reading pre-stored calibration vectors for different azimuths and frequencies, and selecting N groups of calibration vectors based on the center frequency of the target shortwave signal; calculating steering vectors for the N azimuths of the antenna array at the center frequency based on the three-dimensional coordinates of M antennas; and multiplying the calibration vectors for the N azimuths by the steering vectors for the N azimuths to obtain the expected phase difference vectors for the N azimuths.

[0010] According to a shortwave signal direction finding method for an irregular sparse array provided by the present invention, DOA estimation is performed on N1 groups of calibration vectors within a preset range near a reference azimuth, so as to determine a final direction finding result based on the direction finding results of multiple DOA estimations. The method includes: selecting N1 groups of calibration vectors within a preset range near the reference azimuth from the N groups of calibration vectors, and performing DOA estimation on each of the N1 groups of calibration vectors to obtain N1 groups of direction finding results; eliminating direction finding results that do not fall within the preset range from the N1 groups of direction finding results to obtain N2 groups of direction finding results; and selecting the azimuth and elevation angle with the largest spectral peak from the N2 groups of direction finding results as the final direction finding result.

[0011] According to a shortwave signal direction finding method for an irregular sparse array provided by the present invention, the distance between the signal source and the center of the antenna array is greater than or equal to 5 times the aperture of the antenna array.

[0012] According to a shortwave signal direction finding method of an irregular sparse array provided by the present invention, M antennas have different horizontal and height positions.

[0013] According to a shortwave signal direction finding method of an irregular sparse array provided by the present invention, M antennas have two polarization modes: horizontal and vertical.

[0014] In a second aspect, the present invention further provides a shortwave signal direction finding device with an irregular sparse array, comprising:

[0015] The current phase difference vector calculation module is used to synchronously collect the target shortwave signal using the M antennas of the antenna array, obtain data from M channels, select one of the channels as a reference channel, and calculate the current phase difference vector;

[0016] An expected phase difference vector calculation module is used to select N groups of calibration vectors in N directions according to the center frequency of the target shortwave signal, and determine N groups of expected phase difference vectors in N directions;

[0017] A reference orientation determination module is used to perform correlation operations on the current phase difference vector and N groups of expected phase difference vectors, and use the orientation corresponding to the maximum peak obtained as the reference orientation;

[0018] The direction finding result determination unit is configured to perform DOA estimation on N1 groups of calibration vectors within a preset range near the reference azimuth, so as to determine a final direction finding result based on the direction finding results of the multiple DOA estimations.

[0019] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the shortwave signal direction finding method for an irregular sparse array as described above are implemented.

[0020] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the shortwave signal direction finding method for an irregular sparse array as described in any one of the above.

[0021] The present invention provides a method and device for shortwave direction finding using irregular sparse arrays. This method addresses the ambiguity in direction finding for irregular sparse arrays by using correlation peaks between the current phase difference vector and the expected phase difference vectors at different azimuths to determine the azimuth range, reducing the computational complexity of DOA estimation. The method then fuses the direction finding results using azimuth consistency determination and DOA spectrum peak size comparison to obtain a correct direction finding result. This method effectively resolves the ambiguity in direction finding for irregular sparse arrays, improving the direction finding capability for signals with multiple polarization modes while maintaining both accuracy and real-time performance.

[0022] The present invention adopts an array of antenna elements with different horizontal and vertical positions, eliminating angle ambiguity in azimuth and elevation at the same time; adopts a dual-polarized antenna to receive incoming wave signals for direction finding, making full use of the two polarization components of shortwave skywave signals, thereby improving direction finding capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 It is a flow chart of the shortwave signal direction finding method of the irregular sparse array provided by the present invention;

[0025] Figure 2 This is a design principle diagram of the shortwave direction finding method of the dual-polarization irregular sparse array provided by the present invention;

[0026] Figure 3 This is a diagram showing the principle of implementing the direction finding result fusion processing provided by the present invention;

[0027] Figure 4 1 is a diagram showing the measured results of ground wave direction finding provided by an embodiment of the present invention;

[0028] Figure 5 1 is a diagram showing the measured results of skywave direction finding provided by an embodiment of the present invention;

[0029] Figure 6 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0031] It should be noted that, in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "include a ..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0032] The terms "first," "second," and the like in this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that such terms are interchangeable where appropriate, so that embodiments of this application can be implemented in an order other than that illustrated or described herein. Furthermore, the terms "first," "second," and the like generally distinguish objects of a class and do not limit the number of objects; for example, the first object can be one or more. Furthermore, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the connected objects.

[0033] The following combination Figures 1-6 The shortwave signal direction finding method and device for an irregular sparse array provided by the embodiments of the present invention are described.

[0034] Figure 1 FIG. 1 is a flow chart of a shortwave signal direction finding method for an irregular sparse array provided by the present invention, such as Figure 1 As shown, including but not limited to the following steps:

[0035] Step 101: Use M antennas of an antenna array to synchronously collect target shortwave signals, obtain data from M channels, select one of the channels as a reference channel, and calculate a current phase difference vector.

[0036] Optionally, the antenna array in the present invention is an irregular sparse array layout with two polarization modes, horizontal and vertical, and includes M antennas.

[0037] A channel is selected from the data of M channels as a reference channel, and the phase difference of each antenna relative to the reference channel is calculated to form a current phase difference vector.

[0038] Optionally, the M antennas have different horizontal and height positions.

[0039] Optionally, the distance between the signal source and the center of the antenna array is greater than or equal to 5 times the aperture of the antenna array.

[0040] Step 102: Select N groups of calibration vectors in N directions according to the center frequency of the target shortwave signal, and determine N groups of expected phase difference vectors in N directions.

[0041] Optionally, step 102 is implemented as follows:

[0042] (1) Read the pre-stored calibration vectors of different azimuths and frequencies, and select N groups of calibration vectors according to the center frequency of the target shortwave signal.

[0043] The present invention can pre-establish a database containing calibration vector data of different orientations and frequencies, which are usually obtained through precise measurements in a laboratory environment or simulated by simulation software.

[0044] According to the center frequency of the target shortwave signal, a series of calibration vectors closest to the frequency are found in the database.

[0045] (2) Based on the three-dimensional coordinates of the M antennas, the steering vectors of the antenna array in N directions at the center frequency are calculated.

[0046] Based on the precise three-dimensional coordinates of the M antennas in the antenna array, and for a given center frequency, steering vectors are calculated at different azimuths according to the antenna array's geometric layout and electromagnetic wave propagation characteristics. The steering vector represents the antenna array's response to an incident signal in a specific direction.

[0047] (3) Multiply the calibration vectors of the N directions with the steering vectors of the N directions correspondingly to obtain the expected phase difference vectors of the N directions.

[0048] For each selected orientation, the corresponding calibration vector is element-wise multiplied by the steering vector. This is done to determine the relationship between the actual phase difference and the ideal phase difference at that orientation. Through these multiplications, the desired phase difference vectors for each of the N orientations can be obtained.

[0049] Step 103: performing correlation operations on the current phase difference vector and the N groups of expected phase difference vectors, and taking the obtained azimuth corresponding to the maximum peak as the reference azimuth.

[0050] Optionally, the reference orientation is denoted as A in the present invention.

[0051] Step 104: performing DOA estimation on each of the N1 groups of calibration vectors within a preset range near the reference azimuth, so as to determine a final direction finding result based on the direction finding results of multiple DOA estimations.

[0052] Optionally, step 104 is implemented as follows:

[0053] (1) Select N1 sets of calibration vectors within a preset range A1 near the reference azimuth A from the N sets of calibration vectors, perform DOA estimation on each of them, and obtain N1 sets of direction-finding results.

[0054] Based on the previously determined reference orientation, a preset range A1 is defined as [A-α, A+α], where α is a preset angle, and N1 sets of calibration vectors are selected within this range.

[0055] The present invention uses these N1 sets of calibration vectors to perform DOA estimation and obtain N1 sets of direction finding results; wherein, DOA estimation can adopt various methods, such as minimum variance distortionless response (MVDR), multiple signal classification (MUSIC), estimated signal parameter rotation invariance technique (ESPRIT), etc.

[0056] (2) Eliminate the direction finding results that do not fall within the preset range from the N1 group of direction finding results to obtain the N2 group of direction finding results.

[0057] For each of the N1 azimuth angles obtained from multiple DOA estimations, determine whether the azimuth angle is within the range [A - α, A + α]. If not, discard the result; if it is, retain it. After N1 rounds of screening, obtain N2 direction-finding results.

[0058] (3) The azimuth and elevation angles with the largest spectrum peaks in the N2 group of direction-finding results are selected as the final direction-finding results.

[0059] For the N2 direction-finding results, analyze the spectrum peak (i.e., the value with the highest intensity) and select the azimuth and elevation angle with the largest spectrum peak as the final direction-finding result. This is because the location with the largest spectrum peak often represents the direction with the strongest signal, that is, the direction with the most likely target.

[0060] This invention addresses the direction-finding ambiguity issue in irregular sparse arrays. It uses correlation peaking between the current phase difference vector and the expected phase difference vectors at different azimuths to determine the azimuth angle range, reducing the computational complexity of DOA estimation. It then fuses the direction-finding results using azimuth consistency determination and DOA spectrum peak size comparison to obtain the correct result. This method effectively resolves the direction-finding ambiguity issue in irregular sparse arrays, improving the direction-finding capability for signals with multiple polarization modes while maintaining both accuracy and real-time performance.

[0061] The present invention adopts an array of antenna elements with different horizontal and vertical positions, eliminating angle ambiguity in azimuth and elevation at the same time; adopts a dual-polarized antenna to receive incoming wave signals for direction finding, making full use of the two polarization components of shortwave skywave signals, thereby improving direction finding capability.

[0062] Figure 2 This is a design principle diagram of the shortwave direction finding method of the dual-polarization irregular sparse array provided by the present invention, such as Figure 2 As shown, the method of the present invention is primarily used for direction finding of shortwave communication signals. After completing multi-channel synchronous acquisition of dual-polarized antenna array signals, the current phase difference vector is calculated. Based on the known target signal center frequency, the expected phase difference vector is calculated and constructed. The direction finding azimuth range is determined by correlation between the two. Multiple DOA estimations are performed within this azimuth, and the results are fused to output the final direction finding result.

[0063] The method comprises:

[0064] Use M antennas to receive the target shortwave signal with a center frequency of f, synchronously acquire M channel data, select one channel as the reference channel, and calculate the current phase difference vector;

[0065] Read the calibration vectors of N different frequencies in different directions, and select the closest N sets of calibration vectors according to the target signal frequency;

[0066] Based on the three-dimensional coordinates of the M antennas, the steering vectors of the array in N directions at frequency f are calculated;

[0067] Multiply the calibration vectors of N directions by the steering vectors of N directions respectively to obtain the expected phase difference vectors of N directions;

[0068] Perform correlation operations on the current phase difference vector and N groups of expected phase difference vectors, and use the azimuth corresponding to the maximum peak as the reference azimuth A;

[0069] Select N1 sets of calibration vectors within a certain range A1 near the reference azimuth A from the N sets of calibration vectors to perform DOA estimation, and obtain N1 sets of direction finding results;

[0070] Eliminate the direction finding results that do not belong to range A1 from the N1 group of direction finding results to obtain the N2 group of direction finding results;

[0071] The azimuth and elevation angles with the largest spectrum peaks in the N2 group of direction finding results are selected as the final direction finding results.

[0072] The method of the present invention is now further described by way of examples:

[0073] The dual-polarization irregular sparse array has a total of M array elements (antennas), and the three-dimensional coordinates of each array element are (x i ,y i , z i ), the three-dimensional coordinates of the reference array element are (0,0,0), the signal incident azimuth (relative to the north direction) is φ, the pitch angle (relative to the ground plane) is θ, the incident signal frequency is f, and the speed of light is c. Then the delay of each array element is:

[0074]

[0075] Where i = 1, 2, 3,…, M.

[0076] The steering vector of each array element is:

[0077]

[0078] The calibration vector of each array element at the closest frequency f is:

[0079]

[0080] Then the corresponding elements of the two are multiplied to obtain the expected phase difference vector:

[0081]

[0082] N groups of expected phase difference vectors can be obtained from N different azimuth angles:

[0083] E=[e1e2 e3…e N ];

[0084] Perform FFT transformation on the synchronously collected M channel data, find the maximum peak point after taking the modulus, and take the frequency domain normalized complex vector of the peak point as the current phase difference vector of the received signal. Compare the current phase difference vector with the N groups of expected phase difference vectors [e1e2 e3…e N ]Sum and modulus the relevant values ​​one by one, compare the sizes of these N modulus values, and the direction represented by the largest modulus value is the direction finding reference direction A.

[0085] Based on the reference azimuth A, a certain range A1∈[A-α,A+α] is selected as the possible azimuth distribution range. Within this range, there are N1 azimuth calibration vectors. The currently synchronously collected M-channel IQ data is conjugate-multiplied by each of these N1 calibration vectors to obtain the calibrated IQ data. DOA estimation is performed on each of these data to obtain N1 direction-finding results.

[0086] Figure 3 This is a schematic diagram of the implementation principle of the direction finding result fusion processing provided by the present invention. Figure 3 Provide explanation.

[0087] For each of the N1 azimuth angles obtained from multiple DOA estimations, determine whether the azimuth angle is within the range [A - α, A + α]. If not, discard the result; if it is, retain it. After N1 rounds of screening, obtain N2 direction-finding results.

[0088] From each of the N2 direction-finding results, the corresponding DOA estimation spectrum peaks are extracted and compared. According to the principle of direction-finding, the peak size indicates the degree of correlation between the calibrated received signal and the steering vector corresponding to the azimuth. A higher peak value indicates a higher correlation. Therefore, the azimuth and elevation angle corresponding to the highest peak in the N2 direction-finding spectra are selected as the final direction-finding result.

[0089] The effect of the above method on the direction finding of the actual shortwave ground wave and sky wave signals is as follows: Figure 4 and Figure 5 As shown, Figure 4 is a diagram showing the actual measurement results of ground wave direction finding provided by an embodiment of the present invention. Figure 5This figure shows the measured results of skywave direction finding provided by an embodiment of the present invention. The test sample uses 68 antennas for synchronous acquisition, including 34 horizontally polarized antennas and 34 vertically polarized antennas. The entire antenna array is arranged in an irregular sparse pattern with an aperture greater than 1 km.

[0090] See also Figure 4 , is the direction finding result of the array for 7762.5kHz ground wave signal. The true value of azimuth is 152.5°, and the actual measured azimuth is 152.7°, with an error of only 0.2°. Figure 5 , which shows the array's direction finding results for an 11630 kHz skywave signal. The true azimuth is 102.9°, while the actual measured azimuth is 102.4°, with an error of only 0.5°. This shows that the method of the present invention enables a dual-polarization irregular sparse array to achieve high accuracy in both groundwave and skywave direction finding.

[0091] On the other hand, the present invention also provides a shortwave signal direction finding device with an irregular sparse array, comprising:

[0092] The current phase difference vector calculation module is used to synchronously collect the target shortwave signal using the M antennas of the antenna array, obtain data from M channels, select one of the channels as a reference channel, and calculate the current phase difference vector;

[0093] An expected phase difference vector calculation module is used to select N groups of calibration vectors in N directions according to the center frequency of the target shortwave signal, and determine N groups of expected phase difference vectors in N directions;

[0094] A reference orientation determination module is used to perform correlation operations on the current phase difference vector and N groups of expected phase difference vectors, and use the orientation corresponding to the maximum peak obtained as the reference orientation;

[0095] The direction finding result determination unit is configured to perform DOA estimation on N1 groups of calibration vectors within a preset range near the reference azimuth, so as to determine a final direction finding result based on the direction finding results of the multiple DOA estimations.

[0096] It should be noted that the shortwave signal direction finding device for an irregular sparse array provided in an embodiment of the present invention can execute the shortwave signal direction finding method for an irregular sparse array described in any of the above embodiments during specific operation, which will not be described in detail in this embodiment.

[0097] Figure 6 Schematic diagram of the structure of the electronic device provided by the present invention, such as Figure 6As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 may call logic instructions in the memory 630 to execute the shortwave signal direction finding method for an irregular sparse array.

[0098] In addition, the logic instructions in the above-mentioned memory 630 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0099] On the other hand, the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the shortwave signal direction finding method for an irregular sparse array provided in the above embodiments.

[0100] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the shortwave signal direction finding method for an irregular sparse array provided in the above embodiments.

[0101] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0102] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A shortwave signal direction finding method for an irregular sparse array, characterized in that: include: The target shortwave signal is synchronously collected using the M antennas of the antenna array to obtain data from M channels. One of the channels is selected as the reference channel to calculate the current phase difference vector. According to the center frequency of the target shortwave signal, N groups of calibration vectors in N directions are selected to determine N groups of expected phase difference vectors in N directions; Perform correlation operations on the current phase difference vector and N groups of expected phase difference vectors, and use the azimuth corresponding to the maximum peak as the reference azimuth; DOA estimation is performed on each of N1 groups of calibration vectors within a preset range near the reference azimuth, so as to determine a final direction finding result based on the direction finding results of multiple DOA estimations.

2. The shortwave signal direction finding method of irregular sparse array according to claim 1, characterized in that: According to the center frequency of the target shortwave signal, N groups of calibration vectors in N directions are selected to determine N groups of expected phase difference vectors in N directions, including: Read the pre-stored calibration vectors of different azimuths and frequencies, and select N groups of calibration vectors according to the center frequency of the target shortwave signal; Based on the three-dimensional coordinates of the M antennas, the steering vectors of the antenna array in N directions at the center frequency are calculated; The calibration vectors of the N azimuths are multiplied by the steering vectors of the N azimuths to obtain the expected phase difference vectors of the N azimuths.

3. The shortwave signal direction finding method of irregular sparse array according to claim 1, characterized in that: Within a preset range near the reference azimuth, DOA estimation is performed on each of the N1 sets of calibration vectors to determine the final direction finding result based on the direction finding results of multiple DOA estimations, including: Selecting N1 sets of calibration vectors within a preset range near the reference azimuth from the N sets of calibration vectors, and performing DOA estimation on each of them to obtain N1 sets of direction finding results; Eliminate direction finding results that do not fall within a preset range from the N1 group of direction finding results to obtain the N2 group of direction finding results; The azimuth and elevation angles with the largest spectrum peaks in the N2 group of direction finding results are selected as the final direction finding results.

4. The shortwave signal direction finding method of irregular sparse array according to claim 1, characterized in that: The distance between the signal source and the center of the antenna array is greater than or equal to 5 times the aperture of the antenna array.

5. The shortwave signal direction finding method of irregular sparse array according to claim 1, characterized in that: The M antennas have different horizontal and height positions.

6. The shortwave signal direction finding method of irregular sparse array according to claim 1, characterized in that: The M antennas have two polarization modes: horizontal and vertical.

7. A shortwave signal direction finding device with irregular sparse array, characterized in that: include: The current phase difference vector calculation module is used to synchronously collect the target shortwave signal using the M antennas of the antenna array, obtain data from M channels, select one of the channels as a reference channel, and calculate the current phase difference vector; An expected phase difference vector calculation module is used to select N groups of calibration vectors in N directions according to the center frequency of the target shortwave signal, and determine N groups of expected phase difference vectors in N directions; A reference orientation determination module is used to perform correlation operations on the current phase difference vector and N groups of expected phase difference vectors, and use the orientation corresponding to the maximum peak obtained as the reference orientation; The direction finding result determination unit is configured to perform DOA estimation on N1 groups of calibration vectors within a preset range near the reference azimuth, so as to determine a final direction finding result based on the direction finding results of the multiple DOA estimations.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the shortwave signal direction finding method for an irregular sparse array are implemented as claimed in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the shortwave signal direction finding method for an irregular sparse array are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the shortwave signal direction finding method for an irregular sparse array are implemented.

Images