A method of distributed angle finding by interferometry based on digital beam filling

Abstract

The application relates to a kind of distributed interference angle measurement methods based on digital beam filling, first, the aperture size D of single antenna and radar signal frequency f are used to determine the directional diagram of each feed channel of each antenna in distributed antenna array, then, the directional diagram of each feed channel in single antenna and the array distribution of distributed antenna are used to determine the antenna directional diagram after coherent synthesis of distributed array, further, the interval L between antennas and the number N of antennas are used to determine the number of times of filling beam and the corresponding steering vector of each filling of the antenna directional diagram after coherent synthesis of distributed array, all filled antenna directional diagrams are vector added to form filled antenna directional diagram, finally, target angle measurement is realized through sum and difference beam.The application can realize accurate measurement of target direction of arrival through the method of digital beam forming, has low technical difficulty and low cost, and is an effective technical approach to solve distributed coherent angle measurement.

Description

Technical Field

[0001] This invention relates to the field of radar technology, and in particular to a distributed interferometric angle measurement method based on digital beam filling. Background Technology

[0002] As human exploration of space deepens, effective detection of space targets has become an urgent task in the field of radar detection. The demands on radar detection performance are constantly increasing (target distances are increasing, and target RCS is decreasing). Traditional methods of improving system detection performance by increasing the power-aperture product of the radar system are becoming increasingly technically challenging and unsustainable. Distributed coherent receiver detection is an effective way to detect small targets at long distances. However, when using distributed coherent receivers, the antennas are sparsely arranged. Within the beam coverage area of ​​each antenna, grating lobes are inevitably generated, making it difficult to distinguish which lobe the target originates from, thus hindering angular target localization. Summary of the Invention

[0003] To address the existing technical problems, this invention provides a distributed interferometric angle measurement method based on digital beam filling.

[0004] The specific content of this invention is as follows: A distributed interferometric angle measurement method based on digital beamfilling. This method digitizes the reception of each antenna in a distributed antenna array and measures the angle of the target using digital sum-difference beamforming. This invention uses a reflector antenna containing three feed sources (left, center, and right) to illustrate the principle of one-dimensional angle measurement achieved by the distributed interferometric angle measurement method based on digital beamfilling. The three feed sources are respectively... , This indicates that the method is also applicable to two-dimensional angle measurements.

[0005] This method first depends on the aperture size of a single antenna. and radar signal frequency The radiation pattern of each feed channel of each antenna in the distributed antenna array is determined. Then, based on the radiation pattern of each feed channel in a single antenna and the array distribution of the distributed antennas, the antenna radiation pattern after coherent synthesis of the distributed array is determined. Further, the spacing between the antennas is considered. and the number of antennas The number of times the antenna pattern after coherent synthesis of the distributed array needs to be filled with beams and the corresponding steering vector for each filling are determined. All filled antenna patterns are vector-summed to form the filled antenna pattern. Finally, the target angle is measured by the sum and difference beams.

[0006] The distributed interferometric angle measurement method based on digital beam filling of the present invention includes the following specific steps:

[0007] (1) Based on the aperture size of each antenna in the distributed antenna array and radar center frequency Determine the radiation pattern of each feed channel for each antenna. , and the beamwidth of the antenna pattern at each site. ,in, Represents the first in a distributed antenna array One antenna, , The tables represent the left, center, and right feed sources for each station.

[0008] (2) Based on the number of distributed antenna arrays and the spacing between antennas Sure The grating lobe width of the combined antenna radiation pattern and the spacing between the grating lobes .

[0009] (3) The grid lobe spacing obtained from steps (1) and (2) and grid width Calculate the number of beams that need to be filled. .

[0010] (4) Based on the radar signal frequency and grid width Calculate the steering vector for each feed and each filled beam. ,in, Represents the first in a distributed site One antenna, Indicates the first One filling beam, It represents the speed of light.

[0011] (5) Calculate the fill beam of each feed source of each distributed antenna. , , ,in, Indicates the first One filling beam.

[0012] (6) Calculate the antenna pattern after superimposing the fill beam vectors of each feed for each antenna. , , ,in, Indicates the first One filling beam.

[0013] (7) Calculate The sum of the antenna filling wave vectors and the beam Sum and difference beam

[0014] (8) Calculation The back difference and ratio curves after superposition of antenna-filled beam vectors .

[0015] (9) Calculate the target’s angle of arrival direction using the difference and sum ratio curve based on the ratio of the difference channel to the sum channel.

[0016] The beneficial effects of this invention are: it can achieve accurate measurement of the target wave direction of arrival through digital beamforming, which is technically simple and inexpensive, and is an effective technical approach to solve the problem of distributed coherent angle measurement. Attached Figure Description

[0017] The specific embodiments of the present invention will be further explained below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the distributed antenna array's polar feed arrangement.

[0019] Figure 2 The radiation pattern of each feed antenna in each antenna of the distributed antenna array;

[0020] Figure 3 The radiation patterns of each feed antenna after distributed synthesis;

[0021] Figure 4 Fill the beams for each feed source after distributed synthesis;

[0022] Figure 5 This is the superposition pattern of the vectors of each filler beam after distributed synthesis;

[0023] Figure 6 The sum and difference beam pattern after filling beam vector superposition;

[0024] Figure 7 The difference and ratio curves after the beam vectors are superimposed. Detailed Implementation

[0025] Combination Figures 1-7 This invention provides a distributed interferometric angle measurement method based on digital beamfill. This method digitizes the reception of signals from each antenna in a distributed antenna array and measures the angle of the target using digital sum-difference beamforming. The invention uses a reflector antenna with three feed sources (left, center, and right) to illustrate the one-dimensional angle measurement principle achieved by the distributed interferometric angle measurement method based on digital beamfill. , This indicates that the method is also applicable to two-dimensional angle measurements.

[0026] This method first depends on the aperture size of a single antenna. and radar signal frequency The radiation pattern of each feed channel of each antenna in the distributed antenna array is determined. Then, based on the radiation pattern of each feed channel in a single antenna and the array distribution of the distributed antennas, the antenna radiation pattern after coherent synthesis of the distributed array is determined. Further, the spacing between the antennas is considered. and the number of antennas The number of times the antenna pattern after coherent synthesis of the distributed array needs to be filled with beams and the corresponding steering vector for each filling are determined. All filled antenna patterns are vector-summed to form the filled antenna pattern. Finally, the target angle is measured by the sum and difference beams.

[0027] (1) The distributed antenna array selected in the embodiment is as follows: Figure 1 As shown, each antenna's reflector antenna includes three feeds (left, center, and right), and the radiation patterns of the three feed lines are as follows. , like Figure 2 As shown, antenna aperture The center frequency of the radar signal is taken Then the beamwidth of the antenna pattern ,in, In a distributed antenna, the first One antenna, , The tables represent the left, center, and right feed sources for each station.

[0028] (2) Based on the number of distributed antennas The antenna patterns of each feed source after synthesis are determined as follows: Figure 3 As shown, and the spacing between the antennas. Sure The grating lobe width of the combined antenna radiation pattern and the spacing between the grating lobes .

[0029] (3) The grid lobe spacing obtained from steps (1) and (2) and grid width Calculate the number of beams that need to be filled. .

[0030] (4) Based on the radar signal frequency and grid width Calculate the steering vector for each feed and each filled beam. ,in, Represents the first in a distributed site One antenna, Indicates the first One filling beam, It represents the speed of light.

[0031] (5) Calculate the fill beam of each feed of each distributed antenna. , , ,in, Indicates the first Each feed fills a beam, and the beam pattern of each feed fills a beam is shown below. Figure 4 As shown.

[0032] (6) Calculate the antenna pattern after superimposing the fill beam vectors of each feed for each antenna. , , like Figure 5 As shown, where, Indicates the first One filling beam.

[0033] (7) Calculate The sum of the antenna filling wave vectors and the beam Sum and difference beam ,like Figure 6 As shown.

[0034] (8) Calculation The difference and ratio curves after the superposition of the filling vectors of the antenna filling waves ,like Figure 6 As shown.

[0035] (9) If the ratio of the target difference channel signal to the sum channel is 0.0966, the target's direction of arrival can be obtained from the difference and sum curve as 0.5° to the left of the beam axis, thus completing the target angle measurement.

[0036] The method for measuring target angle using digital beam filling proposed in this invention can solve the technical problem of accurately measuring the direction of arrival of the target wave due to the presence of grating lobes in distributed coherent detection. At the same time, it can also overcome the defect that the target cannot be detected when it arrives from the gap between the grating lobes, laying a technical foundation for long-distance small target detection using distributed coherent reception.

[0037] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A distributed interferometric angle measurement method based on digital beamfill, characterized in that: include: Step 1: Determine the radiation pattern of each feed channel for each antenna based on the aperture size D of the individual antennas in the distributed antenna array and the radar signal frequency f. , and the beamwidth of the antenna pattern at each site. ,in, , representing the first in a distributed antenna array One antenna, , These represent the left, center, and right feed sources at each station; Step 2: Determine the antenna pattern after coherent synthesis of the distributed antenna array based on the radiation pattern of each feed channel of each antenna in the distributed antenna array and the array distribution of the distributed antennas. Step 3: Determine the number of times the beam needs to be filled and the corresponding steering vector for each filling based on the spacing L between antennas and the number of antennas N in the distributed array coherent synthesis antenna pattern. and the spacing between antennas Sure The grating lobe width of the combined antenna radiation pattern and the spacing between the grating lobes Based on the obtained grating lobe spacing and grid width Calculate the number of beams that need to be filled. According to radar signal frequency and grid width Calculate the steering vector for each feed and each filled beam. ,in, , indicating the first in the distributed site One antenna, , indicating the first One filling beam, Represents the speed of light; Step 4: Vector sum all the filled antenna patterns to form the filled antenna pattern: Calculate the filled beam of each feed of each antenna in the distributed antenna array. , , ; Calculate the antenna pattern after superimposing the fill beam vectors of each feed source for each antenna. , , ; Step 5: Target angle measurement is achieved through sum and difference beams.

2. The distributed interferometric angle measurement method based on digital beam filling according to claim 1, characterized in that: Step 5 includes calculating The sum of the beam vectors of the antenna filling beams and the beam Sum and difference beam .

3. The distributed interferometric angle measurement method based on digital beam filling according to claim 2, characterized in that: Step 5 includes calculating The difference and ratio curves after the superposition of the antenna-filled beam vectors .

4. The distributed interferometric angle measurement method based on digital beam filling according to claim 3, characterized in that: Step 5 includes calculating the target's direction of arrival using the difference-to-sum curve based on the ratio of the target difference channel to the sum channel.

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