Broadband correlation interferometer direction finding control method and system

Abstract

The application provides a broadband correlation interferometer direction finding control method and system, and relates to the technical field of direction finding, and comprises the following steps: a search area limiting step: determining a search range of a phase difference vector correlation coefficient maximum value according to prior angle information and a non-ambiguous angle range; a maximum value searching step: searching for a correlation coefficient maximum value in the search area; a spectrum peak condensation step: performing weighted average on spectrum peaks within a certain range around an azimuth angle and a pitch angle corresponding to the correlation coefficient maximum value, so as to obtain a two-dimensional energy center of the spectrum peaks, and the azimuth angle and the pitch angle corresponding to the two-dimensional energy center are the angle positions of a radiation source. The application has good robustness and direction finding precision superior to that of a traditional algorithm.

Description

Technical Field

[0001] This invention relates to the field of direction finding technology, and more specifically, to a direction finding control method and system for a broadband correlation interferometer. Background Technology

[0002] Correlation interferometry (CIF) is a commonly used direction-finding technique. It measures the phase difference data of a spatial signal across different channels and performs correlation operations with samples from pre-stored data to search for the closest phase difference array, thereby indexing the direction of arrival of the wave. CIF direction finding offers advantages such as high accuracy, simple algorithms, and high speed. Furthermore, it has lower requirements for antenna array structure, can resist certain wavefront distortions, and is insensitive to polarization errors. CIF direction finding technology is widely used in communication positioning, radio spectrum monitoring, electronic countermeasures, and security applications.

[0003] The varying baseline lengths of the interferometer antenna array cause baseline mirroring and phase ambiguity issues in the algorithm during direction finding. When performing nearest neighbor search, there is a certain probability of obtaining incorrect indices, which is particularly severe when performing high-frequency direction finding because high-frequency signals have shorter wavelengths and are more prone to phase ambiguity.

[0004] The paper "Application of Improved Correlation Interferometer Algorithm in DOA Estimation" proposes an improved correlation algorithm based on quadrant classification. First, the time difference of the signal arrival at each array element is converted into a phase difference. Simultaneously, the obtained phase difference is compared with 360°, and the integer and remainder results are recorded. Then, the remainders are classified by quadrant. Next, the initial estimate of the signal is obtained using the traditional correlation interferometer algorithm. Finally, the final estimate of the signal is obtained through inverse operations. This method can effectively solve only the problems of baseline mirror symmetry and phase ambiguity. However, it relies on the correctness of phase difference deambiguation, increasing the algorithm's complexity, and it does not consider the effects of angle, frequency, and sample library mismatch.

[0005] Because broadband interferometers have a wide frequency range and a large database, when determining the direction of unknown radiation sources, the actual spatial signal frequency and angle are often not completely consistent with the samples in the database. When the frequency, angle and samples in the database are mismatched, direction finding errors are likely to occur. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a broadband correlation interferometer direction finding control method and system.

[0007] According to the present invention, a broadband correlation interferometer direction finding control method and system are provided, the scheme of which is as follows:

[0008] Firstly, a broadband correlation interferometer control direction finding method is provided, the method comprising:

[0009] Limiting the search area step: Determine the search range for the maximum value of the phase difference vector correlation coefficient based on prior angle information and the unambiguous angle range;

[0010] Maximum value search steps: Find the maximum correlation coefficient within the search area;

[0011] Peak agglomeration step: Within the beamwidth range around the azimuth and elevation angles corresponding to the maximum correlation coefficient, the peaks are weighted and averaged to obtain the two-dimensional energy center of the peaks. The azimuth and elevation angles corresponding to the two-dimensional energy center are the angular positions of the radiation source.

[0012] Preferably, the search range for determining the maximum value of the phase difference vector correlation value in the step of limiting the search region includes:

[0013] θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0014] θ0 and φ0 are the prior angle information of azimuth and elevation angles, and Δθ and Δφ are the unambiguous angle ranges of the spectral peaks related to azimuth and elevation angles.

[0015] The prior angles θ0 and φ0 of the selected azimuth and elevation angles are obtained based on the previous direction finding results or obtained through extrapolation filtering.

[0016] Preferably, the unambiguous angle range of the relevant spectral peaks in the step of defining the search region is determined based on the main lobe width of the synthesized radiation pattern of the correlation interferometer antenna, as shown in the following formula.

[0017]

[0018]

[0019] Where λ is the wavelength of the electromagnetic wave, and D1 and D2 are the aperture sizes of the array antenna in the azimuth and elevation dimensions, respectively.

[0020] Preferably, the maximum value search step includes:

[0021] max{ρ(θ,φ)}θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0022] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library.

[0023] Preferably, the peak agglomeration step includes:

[0024] The range of azimuth and elevation angles selected for weighted averaging during spectral peak aggregation is determined by the main lobe width of the synthesized pattern from the correlated interferometer antenna, as shown in the following formula:

[0025] Θ = [θ1 - Δθ, θ1 + Δθ]

[0026] Ψ=[φ1-Δφ,φ1+Δφ]

[0027] Where Θ and Ψ are the range of azimuth and elevation angles selected by weighted average during spectral peak aggregation, θ1 and φ1 are the azimuth and elevation angles corresponding to the maximum value of ρ(θ,φ) obtained by the maximum value search step; Δθ and Δφ are the unambiguous angle ranges of azimuth and elevation angle related spectral peaks.

[0028] The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation.

[0029]

[0030]

[0031] in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

[0032] Secondly, a broadband correlation interferometer direction finding and control system is provided, the system comprising:

[0033] Limiting the search area module: Determines the search range for the maximum value of the phase difference vector correlation coefficient based on prior angle information and the unambiguous angle range;

[0034] Maximum value search module: Finds the maximum correlation coefficient within the search area;

[0035] Spectral peak aggregation module: Within the beamwidth range around the azimuth and elevation angles corresponding to the maximum correlation coefficient, the spectral peaks are weighted and averaged to obtain the two-dimensional energy center of the spectral peaks. The azimuth and elevation angles corresponding to the two-dimensional energy center are the angular positions of the radiation source.

[0036] Preferably, the search range for determining the maximum value of the phase difference vector correlation value in the defined search region module includes:

[0037] θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0038] θ0 and φ0 are the prior angle information of azimuth and elevation angles, and Δθ and Δφ are the unambiguous angle ranges of the spectral peaks related to azimuth and elevation angles.

[0039] The prior angles θ0 and φ0 of the selected azimuth and elevation angles are obtained based on the previous direction finding results or obtained through extrapolation filtering.

[0040] Preferably, the unambiguous angle range of the correlation spectral peaks in the defined search region module is determined based on the main lobe width of the synthesized radiation pattern of the correlation interferometer antenna, as shown in the following formula.

[0041]

[0042]

[0043] Where λ is the wavelength of the electromagnetic wave, and D1 and D2 are the aperture sizes of the array antenna in the azimuth and elevation dimensions, respectively.

[0044] Preferably, the maximum value search module includes the following steps:

[0045] max{ρ(θ,φ)} θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0046] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library.

[0047] Preferably, the peak agglomeration module includes:

[0048] The range of azimuth and elevation angles selected for weighted averaging during spectral peak aggregation is determined by the main lobe width of the synthesized pattern from the correlated interferometer antenna, as shown in the following formula:

[0049] Θ = [θ1 - Δθ, θ1 + Δθ]

[0050] Ψ=[φ1-Δφ,φ1+Δφ]

[0051] Where Θ and Ψ are the range of azimuth and elevation angles selected by weighted average during spectral peak aggregation, θ1 and φ1 are the azimuth and elevation angles corresponding to the maximum value of ρ(θ,φ) obtained by the maximum value search step; Δθ and Δφ are the unambiguous angle ranges of azimuth and elevation angle related spectral peaks.

[0052] The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation.

[0053]

[0054]

[0055] in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] This invention utilizes region limitation to avoid obtaining erroneous angle values ​​through searching, and further performs spectral peak aggregation in the region near the maximum value obtained from the search, exhibiting good robustness and good angle measurement accuracy for both low-frequency and high-frequency signals.

[0058] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0059] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0060] Figure 1 This is a block diagram illustrating the principle of the broadband correlation interferometer direction finding control method provided in an embodiment of the present invention.

[0061] Figure 2 This is a schematic diagram illustrating the search range area limitation provided in Embodiment 1 of the present invention;

[0062] Figure 3 This is a diagram showing the azimuth angle measurement test results provided in Embodiment 1 of the present invention;

[0063] Figure 4 This is a diagram showing the results of an elevation angle measurement test provided in Embodiment 1 of the present invention;

[0064] Figure 5 This is a schematic diagram illustrating the limitation of the search range area provided in Embodiment 2 of the present invention;

[0065] Figure 6 This is a diagram showing the azimuth angle measurement test results provided in Embodiment 2 of the present invention;

[0066] Figure 7 The figure shows the results of the pitch angle measurement test provided in Embodiment 2 of the present invention. Detailed Implementation

[0067] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0068] This invention provides a direction-finding control method for a broadband correlation interferometer, aiming to solve the problem of direction-finding errors easily occurring when frequency and angle mismatch occurs in existing technologies. It avoids obtaining incorrect angle values ​​through searching, and further improves angle measurement accuracy by performing a weighted average on the region near the maximum value obtained from the search, overcoming the defect that angle measurement results can only fall on the grid. (Refer to...) Figure 1 As shown, the control method specifically includes:

[0069] Limiting the search area step: Determine the search range for the maximum value of the phase difference vector correlation coefficient based on prior angle information and the unambiguous angle range.

[0070] As shown in the following formula:

[0071] θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0072] θ0 and φ0 are the prior angle information of azimuth and elevation angles, and Δθ and Δφ are the unambiguous angle ranges of the spectral peaks related to azimuth and elevation angles.

[0073] The prior angles θ0 and φ0 of the selected azimuth and elevation angles are obtained based on the previous direction finding results or obtained through extrapolation filtering.

[0074] The unambiguous angle range of the relevant spectral peaks in the limited search region step is determined based on the main lobe width of the synthesized radiation pattern of the correlation interferometer antenna, as shown in the following formula.

[0075]

[0076]

[0077] Where λ is the wavelength of the electromagnetic wave, and D1 and D2 are the aperture sizes of the array antenna in the azimuth and elevation dimensions, respectively.

[0078] Maximum value search steps: Find the maximum correlation coefficient within the search area.

[0079] The maximum value search step includes finding the maximum value:

[0080] max{ρ(θ,φ)} θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0081] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library.

[0082] Peak agglomeration step: Within the beamwidth range around the azimuth and elevation angles corresponding to the maximum correlation coefficient, the peaks are weighted and averaged to obtain the two-dimensional energy center of the peaks. The azimuth and elevation angles corresponding to the two-dimensional energy center are the angular positions of the radiation source.

[0083] The peak condensation process includes:

[0084] The range of azimuth and elevation angles selected for weighted averaging during spectral peak aggregation is determined by the main lobe width of the synthesized pattern from the correlated interferometer antenna, as shown in the following formula:

[0085] Θ = [θ1 - Δθ, θ1 + Δθ]

[0086] Ψ=[φ1-Δφ,φ1+Δφ]

[0087] Where Θ and Ψ are the range of azimuth and elevation angles selected by weighted average during spectral peak aggregation, θ1 and φ1 are the azimuth and elevation angles corresponding to the maximum value of ρ(θ,φ) obtained by the maximum value search step; Δθ and Δφ are the unambiguous angle ranges of azimuth and elevation angle related spectral peaks.

[0088] The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation.

[0089]

[0090]

[0091] in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

[0092] This invention also provides a broadband correlation interferometer direction finding control system. This system can be implemented by executing the steps of the broadband correlation interferometer direction finding control method. That is, those skilled in the art can understand the broadband correlation interferometer direction finding control method as a preferred embodiment of the broadband correlation interferometer direction finding control system. Specifically, the system includes the following:

[0093] Limited search area module: Determines the search range for the maximum value of the phase difference vector correlation coefficient based on prior angle information and the unambiguous angle range.

[0094] As shown in the following formula:

[0095] θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0096] θ0 and φ0 are the prior angle information of azimuth and elevation angles, and Δθ and Δφ are the unambiguous angle ranges of the spectral peaks related to azimuth and elevation angles.

[0097] The prior angles θ0 and φ0 of the selected azimuth and elevation angles are obtained based on the previous direction finding results or obtained through extrapolation filtering.

[0098] The unambiguous angular range of the relevant spectral peaks in the limited search region module is determined based on the main lobe width of the synthesized radiation pattern of the correlation interferometer antenna, as shown in the following formula.

[0099]

[0100]

[0101] Where λ is the wavelength of the electromagnetic wave, and D1 and D2 are the aperture sizes of the array antenna in the azimuth and elevation dimensions, respectively.

[0102] Maximum value search module: Finds the maximum correlation coefficient within the search area.

[0103] The maximum value search module includes the following:

[0104] max{ρ(θ,φ)}θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ]

[0105] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library.

[0106] Spectral peak aggregation module: Within the beamwidth range around the azimuth and elevation angles corresponding to the maximum correlation coefficient, the spectral peaks are weighted and averaged to obtain the two-dimensional energy center of the spectral peaks. The azimuth and elevation angles corresponding to the two-dimensional energy center are the angular positions of the radiation source.

[0107] This peak condensation module includes:

[0108] The range of azimuth and elevation angles selected for weighted averaging during spectral peak aggregation is determined by the main lobe width of the synthesized pattern from the correlated interferometer antenna, as shown in the following formula:

[0109] Θ = [θ1 - Δθ, θ1 + Δθ]

[0110] Ψ=[φ1-Δφ,φ1+Δφ]

[0111] Where Θ and Ψ are the range of azimuth and elevation angles selected by weighted average during spectral peak aggregation, θ1 and φ1 are the azimuth and elevation angles corresponding to the maximum value of ρ(θ,φ) obtained by the maximum value search step; Δθ and Δφ are the unambiguous angle ranges of azimuth and elevation angle related spectral peaks.

[0112] The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation.

[0113]

[0114]

[0115] in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

[0116] The present invention will now be described in more detail through examples.

[0117] Example 1:

[0118] Please refer to the above. Figure 1 The principle block diagram of the broadband correlation interferometer direction finding control method and system provided in the embodiments of the present invention.

[0119] In this embodiment, a 6-element broadband uniform circular array antenna is used, with a circular array radius of 60 mm. The coordinates of each element are [30,52], [-30,52], [-60,0], [-30,-52], [30,-52], [60,0], in mm. The phase difference measurement accuracy between interferometer channels is 10°. The sample library frequency interval is 10 MHz, and the azimuth and elevation angle intervals are both 1°. It is assumed that the azimuth and elevation angles of the radiation source are 0.5° and the signal frequency is 15.01 GHz. The nearest sample has a frequency of 15 GHz, an azimuth angle of 0°, and an elevation angle of 0°.

[0120] Step 1: Define the search area. Determine the search range for the maximum value of the phase difference vector correlation based on prior angle information and the unambiguous angle range. The initial value of the radiation source angle information is determined to be around 0° based on spatial location. The size of the unambiguous search area is calculated based on the wavelength:

[0121]

[0122] Where D is the aperture size of the uniform circular array antenna.

[0123] Appendix Figure 2 A correlation plot is generated between the measured phase difference of the radiation source and the phase differences at various angles in a sample library with a frequency of 15 GHz. The area within the black box in the plot represents the defined search region. (See attached...) Figure 2 As can be seen, besides the true angle (0.5°, 0.5°), many other angle positions show high spectral peaks. When performing a global maximum value search, the peaks often fall on other spectral peaks, leading to angle measurement errors. The limited search range obtained by the method proposed in this invention is shown in the attached figure. Figure 2 As shown in the black box in the middle, by utilizing prior information and the limitation of the unambiguous angle range, the ambiguity peak can be excluded, thus avoiding the influence of ambiguity values.

[0124] Step 2: Maximum value search, find the maximum value in the search area described in Step 1.

[0125] max{ρ(θ,φ)} θ∈[-10°,10°],φ∈[-10°,10°]

[0126] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library. The azimuth angle corresponding to the maximum correlation coefficient is 0° and the elevation angle is 1°. This is because the angle interval in the sample library is 1°, so the angle value obtained by the maximum value search can only appear on the grid closest to the true value.

[0127] Step 3: Peak Convergence. Within a certain range around the azimuth and elevation angles corresponding to the maximum correlation coefficient obtained in Step 2, a weighted average is performed on the peaks to obtain the two-dimensional energy center of the peaks. The corresponding azimuth and elevation angles are the angular positions of the radiation source. The range of azimuth and elevation angles selected for weighted averaging during peak convergence is approximately 10°, corresponding to the main lobe width of the interferometer antenna's synthesized radiation pattern, as shown in the following formula.

[0128] Θ = [-10°, 10°]

[0129] Ψ = [-9°, 11°]

[0130] The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation.

[0131]

[0132]

[0133] in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

[0134] The azimuth angle measurement results after 50 Monte Carlo simulations using the traditional correlation interferometer algorithm and the improved method are attached. Figure 3 The elevation angle measurement results are attached. Figure 4 As shown. The root mean square error (RMSE) of azimuth angle measured by the traditional algorithm is 36.8° and the root mean square error (RMSE) of elevation angle is 4.3°; the root mean square error (RMSE) of azimuth angle measured by the algorithm proposed in this invention is 0.6° and the root mean square error (RMSE) of elevation angle is 0.19°.

[0135] As can be seen from the examples, traditional correlation interferometer methods are susceptible to angle mismatch, and there is a certain probability that the search for the maximum value will fall on an incorrect spectral peak, resulting in erroneous angle measurement results. The algorithm proposed in this invention can overcome the influence of ambiguous spectral peaks by limiting the search area, thereby improving the robustness of the angle measurement algorithm and obtaining higher accuracy angle measurement results.

[0136] Example 2:

[0137] Please refer to the above. Figure 1 The principle block diagram of the broadband correlation interferometer direction finding control method and system provided in the embodiments of the present invention.

[0138] The embodiment employs a 6-element broadband uniform circular array antenna with a radius of 60 mm. The coordinates of each element are [30,52], [-30,52], [-60,0], [-30,-52], [30,-52], [60,0], in mm. The phase difference measurement accuracy between interferometer channels is 10°. The sample library frequency interval is 10 MHz, and the azimuth and elevation angle intervals are both 1°.

[0139] Assume the radiation source has an azimuth angle of 0.5°, an elevation angle of 0.5°, and a signal frequency of 4.01 GHz. The nearest sample has a frequency of 4 GHz, an azimuth angle of 0°, and an elevation angle of 0°.

[0140] Step 1: Define the search area. Determine the search range for the maximum value of the phase difference vector correlation based on prior angle information and the unambiguous angle range. The initial value of the radiation source angle information is determined to be around 0° based on spatial location. The size of the unambiguous search area is calculated based on the wavelength:

[0141]

[0142] Where λ is the wavelength of the electromagnetic wave, and D is the aperture size of the uniform circular array antenna.

[0143] Appendix Figure 5 A correlation plot is generated between the measured phase difference of the radiation source and the phase differences at various angles in a sample library with a frequency of 4 GHz. The area within the black box in the plot represents the defined search region. (See attached...) Figure 5 It can be seen that the correlation spectral peaks are wider at lower frequencies. Although they do not produce blurred values ​​due to spectral peak blurring as they do at higher frequencies, the maximum value search is affected by noise and the flatness of the spectral peaks, which increases the error of the angle measurement results.

[0144] Step 2: Maximum value search, find the maximum value in the search area described in Step 1.

[0145] max{ρ(θ,φ)} θ∈[-35°,35°],φ∈[-35°,35°]

[0146] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library. The maximum correlation coefficient corresponds to an azimuth angle of 1° and an elevation angle of 3°.

[0147] Step 3: Spectral Peak Convergence. Within a certain range around the azimuth and elevation angles corresponding to the maximum correlation coefficient obtained in Step 2, a weighted average is performed on the spectral peaks to obtain the two-dimensional energy center of the peaks. The corresponding azimuth and elevation angles are the angular positions of the radiation source. The range of azimuth and elevation angles selected for weighted averaging during spectral peak convergence is approximately 35°, with the main lobe width of the interferometer antenna's synthesized radiation pattern being approximately 35°, as shown in the following formula.

[0148] Θ = [-34°, 36°]

[0149] Ψ = [-32°, 38°]

[0150] The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation.

[0151]

[0152]

[0153] in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

[0154] The azimuth angle measurement results after 50 Monte Carlo simulations using the traditional correlation interferometer algorithm and the improved method are attached. Figure 6 The elevation angle measurement results are attached. Figure 7 As shown. The root mean square error (RMSE) of azimuth angle measured by the traditional algorithm is 2.52° and the root mean square error (RMSE) of elevation angle is 1.47°; the root mean square error (RMSE) of azimuth angle measured by the algorithm proposed in this invention is 0.74° and the root mean square error (RMSE) of elevation angle is 0.77°.

[0155] As can be seen from the examples, the results obtained by both the traditional algorithm and the algorithm proposed in this invention fluctuate around the true value without any obvious errors. Because the proposed algorithm focuses on the spectral peak center, it obtains higher angle measurement results. Furthermore, the traditional algorithm is affected by the sample angle interval when searching for the maximum value. Taking the simulation above as an example, the ideal angle value after sample matching using the traditional algorithm is only 0° or 1°, and it cannot obtain the 0.5° angle value, which is not in the sample library. The angle value obtained by the proposed algorithm after focusing is not limited by the sample angle interval, further improving the angle measurement accuracy.

[0156] This invention provides a broadband correlation interferometer direction finding control method and system, which has good robustness and direction finding accuracy superior to traditional algorithms.

[0157] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0158] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A direction-finding control method for a broadband correlation interferometer, characterized in that, include: Limiting the search area step: Determine the search range for the maximum value of the phase difference vector correlation coefficient based on prior angle information and the unambiguous angle range; Maximum value search steps: Find the maximum correlation coefficient within the search area; Peak agglomeration step: Within the beamwidth range around the azimuth and elevation angles corresponding to the maximum correlation coefficient, the peaks are weighted and averaged to obtain the two-dimensional energy center of the peaks. The azimuth and elevation angles corresponding to the two-dimensional energy center are the angular positions of the radiation source.

2. The broadband correlation interferometer direction finding control method according to claim 1, characterized in that, The search range for determining the maximum value of the phase difference vector correlation value in the step of limiting the search region includes: θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ] θ0 and φ0 are the prior angle information of azimuth and elevation angles, and Δθ and Δφ are the unambiguous angle ranges of the spectral peaks related to azimuth and elevation angles. The prior angles θ0 and φ0 of the selected azimuth and elevation angles are obtained based on the previous direction finding results or obtained through extrapolation filtering.

3. The broadband correlation interferometer direction finding control method according to claim 2, characterized in that, In the step of defining the search region, the unambiguous angle range of the relevant spectral peaks is determined based on the main lobe width of the synthesized radiation pattern of the correlation interferometer antenna, as shown in the following formula. Where λ is the wavelength of the electromagnetic wave, and D1 and D2 are the aperture sizes of the array antenna in the azimuth and elevation dimensions, respectively.

4. The broadband correlation interferometer direction finding control method according to claim 1, characterized in that, The maximum value search step includes finding the maximum value, which includes: max{ρ(θ,φ)}θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library.

5. The broadband correlation interferometer direction finding control method according to claim 4, characterized in that, The peak condensation step includes: The range of azimuth and elevation angles selected for weighted averaging during spectral peak aggregation is determined by the main lobe width of the synthesized pattern from the correlated interferometer antenna, as shown in the following formula: Θ = [θ1 - Δθ, θ1 + Δθ] Ψ=[φ1-Δφ,φ1+Δφ] Where Θ and Ψ are the range of azimuth and elevation angles selected by weighted average during spectral peak aggregation, θ1 and φ1 are the azimuth and elevation angles corresponding to the maximum value of ρ(θ,φ) obtained by the maximum value search step; Δθ and Δφ are the unambiguous angle ranges of azimuth and elevation angle related spectral peaks. The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation. in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

6. A broadband correlation interferometer direction finding control system, characterized in that, include: Limiting the search area module: Determines the search range for the maximum value of the phase difference vector correlation coefficient based on prior angle information and the unambiguous angle range; Maximum value search module: Finds the maximum correlation coefficient within the search area; Spectral peak aggregation module: Within the beamwidth range around the azimuth and elevation angles corresponding to the maximum correlation coefficient, the spectral peaks are weighted and averaged to obtain the two-dimensional energy center of the spectral peaks. The azimuth and elevation angles corresponding to the two-dimensional energy center are the angular positions of the radiation source.

7. The broadband correlation interferometer direction finding control system according to claim 6, characterized in that, The search range for determining the maximum value of the phase difference vector correlation value in the defined search region module includes: θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ] θ0 and φ0 are the prior angle information of azimuth and elevation angles, and Δθ and Δφ are the unambiguous angle ranges of the spectral peaks related to azimuth and elevation angles. The prior angles θ0 and φ0 of the selected azimuth and elevation angles are obtained based on the previous direction finding results or obtained through extrapolation filtering.

8. The broadband correlation interferometer direction finding control system according to claim 7, characterized in that, The unambiguous angle range of the relevant spectral peaks in the defined search region module is determined based on the main lobe width of the synthesized radiation pattern of the correlation interferometer antenna, as shown in the following formula. Where λ is the wavelength of the electromagnetic wave, and D1 and D2 are the aperture sizes of the array antenna in the azimuth and elevation dimensions, respectively.

9. The broadband correlation interferometer direction finding control system according to claim 6, characterized in that, The maximum value search module includes the following: max{ρ(θ,φ)}θ∈[θ0-Δθ,θ0+Δθ],φ∈[φ0-Δφ,φ0+Δφ] Where ρ(θ,φ) is the correlation coefficient between the complex phase difference vector measured by the interferometer and the complex phase difference vector in the template library.

10. The broadband correlation interferometer direction finding control system according to claim 9, characterized in that, The peak condensation module includes: The range of azimuth and elevation angles selected for weighted averaging during spectral peak aggregation is determined by the main lobe width of the synthesized pattern from the correlated interferometer antenna, as shown in the following formula: Θ = [θ1 - Δθ, θ1 + Δθ] Ψ=[φ1-Δφ,φ1+Δφ] Where Θ and Ψ are the range of azimuth and elevation angles selected by weighted average during spectral peak aggregation, θ1 and φ1 are the azimuth and elevation angles corresponding to the maximum value of ρ(θ,φ) obtained by the maximum value search step; Δθ and Δφ are the unambiguous angle ranges of azimuth and elevation angle related spectral peaks. The two-dimensional energy center of the spectral peak in the range of Θ and Ψ is obtained as shown in the following equation. in, To improve the azimuth and elevation angle estimates obtained by the algorithm.

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