A radio direction finding method based on combination of virtual array elements and real array elements

Abstract

The application belongs to the technical field of radio direction finding, and discloses a radio direction finding device and method based on combination of virtual array elements and real array elements. The device comprises N antennas averagely distributed on a planar circle and a multichannel receiver, each antenna is composed of M array elements, M is greater than 3, N is greater than 3, and one virtual array element is arranged between every two adjacent array elements in the M array elements. The method can further increase the number and accuracy of detected incoming waves without increasing array elements, and can simultaneously detect more than the number of array elements of incoming waves.

Description

Technical Field

[0001] This invention belongs to the field of radio direction finding technology, and relates to a radio direction finding method based on the combination of virtual array elements and real array elements. Background Technology

[0002] Accurate direction finding technology for radio waves is widely used in both military and civilian fields. For example, it's used to locate signals from radar, walkie-talkies, data links, and other equipment in military facilities, or for radio spectrum management. Commonly used radio direction finding methods include uniform linear arrays and uniform circular arrays. Circular arrays, compared to linear arrays, offer advantages such as no image ambiguity, independent angular resolution, and 360-degree omnidirectional direction finding, thus gaining wider application.

[0003] In selecting elements for a uniform circular array, five or seven elements are generally used, considering economic factors and equipment space requirements. The number of elements affects the number of incoming waves that can be detected and the direction-finding accuracy. Theoretically, the number of incoming waves that can be detected should not exceed the number of array elements. Summary of the Invention

[0004] (a) Purpose of the invention

[0005] The purpose of this invention is to address the problem that commonly used uniform circular arrays are limited by the number of array elements and cannot simultaneously detect more incoming waves than the number of array elements. This invention provides a radio direction finding method based on the combination of virtual array elements and real array elements, which can further increase the number and accuracy of detected incoming waves without increasing the number of array elements, and can simultaneously detect more incoming waves than the number of array elements.

[0006] (II) Technical Solution

[0007] To solve the above-mentioned technical problems, the present invention provides a radio direction finding device based on the combination of virtual array elements and real array elements, which includes: N antennas evenly distributed on a planar circle and a multi-channel receiver, each antenna consisting of M array elements; M is greater than 3, N is greater than 3; among the M array elements, a virtual array element is arranged between two adjacent array elements.

[0008] This invention provides a radio direction finding method based on a combination of virtual and real array elements using a radio direction finding device, comprising the following steps:

[0009] The first step is to down-convert the signal received by each real array element and then perform weighted processing; using dimensional vector To represent the input data for each array, and to calculate the processed data. A two-dimensional matrix after the length of each data segment;

[0010] The second step is to calculate the autocorrelation matrix of the input signal, and then calculate the eigenvalues ​​and corresponding eigenvectors of the autocorrelation matrix.

[0011] The third step is to determine the number of incoming waves by the magnitude of the eigenvalues; if the number of incoming waves is less than M, the direction of incoming waves is calculated; if the number of incoming waves is equal to M, the sampled signal is processed to virtualize M array elements to obtain a new two-dimensional matrix.

[0012] The fourth step is to calculate the autocorrelation matrix of the input signal, the eigenvalues ​​of the autocorrelation matrix, and the corresponding eigenvectors. If the autocorrelation matrix is ​​full rank, matrix decomposition is used, and spatial smoothing is employed to average the covariances of the decomposed submatrices to obtain the smoothed and corrected estimated matrix.

[0013] The fifth step is to calculate the number of incoming waves and their directions for the new estimated matrix.

[0014] (III) Beneficial Effects

[0015] The radio direction finding method based on the combination of virtual and real array elements provided by the above technical solution can further increase the number and accuracy of detected incoming waves without increasing the number of array elements, and can simultaneously detect more incoming waves than the number of array elements. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a uniform circular array element according to an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0018] This invention provides a radio direction finding method based on a combination of virtual and real array elements, which increases the number and accuracy of detected incoming waves without increasing the number of array elements. The core idea of ​​this invention is:

[0019] (1) Add virtual array elements between real array elements.

[0020] by Figure 1 As shown, when there are four real array elements, A1, A2, A3, and A4 are real array elements, which are evenly distributed; A5, A6, A7, and A8 are virtual array elements, which are distributed sequentially between two adjacent real array elements.

[0021] (2) Due to the introduction of virtual array elements, the covariance matrix of the MUSIC algorithm may not be of full rank in special cases, which will result in the eigenvalues ​​obtained by eigenvalue decomposition and the number of incoming waves not satisfying the correspondence. The rank of the matrix is ​​restored by spatial smoothing.

[0022] This embodiment first provides a radio direction finding device based on the combination of virtual array elements and real array elements, including N antennas evenly distributed on a planar circle and a multi-channel receiver, each antenna consisting of M array elements; M is greater than 3, and N is greater than 3.

[0023] In the M array elements, a virtual array element is placed between two adjacent array elements.

[0024] Based on the above-mentioned radio direction finding device, the radio direction finding method based on the combination of virtual array elements and real array elements in this embodiment includes the following steps:

[0025] The first step is to analyze the signals received by each real array element. After downconversion and weighting, The weighted output expression for each array element is:

[0026] (1)

[0027] use dimensional vector To represent the input data for each array, i.e.:

[0028] (2)

[0029] Then passed After the length of each data segment, the two-dimensional matrix becomes:

[0030] (3)

[0031] The second step is to calculate the autocorrelation matrix of the input signal. ,Right now .calculate eigenvalues ​​and corresponding eigenvectors .

[0032] The third step is to determine the number of incoming waves by analyzing the eigenvalues ​​of R. If the number of incoming waves is less than M, the classic MUSIC algorithm is used to calculate the direction of arrival. If the number of incoming waves equals M, the sampled signal is further processed to create M virtual array elements. Therefore, there are a total of 2M array elements, resulting in a new two-dimensional matrix:

[0033] (4)

[0034] The fourth step is to calculate the autocorrelation matrix of the input signal. ,Right now .calculate eigenvalues ​​and corresponding eigenvectors If an autocorrelation matrix appears... In the case of full rank, matrix decomposition is used, and spatial smoothing is employed to average the covariances of the decomposed submatrices, resulting in a smoothed and corrected estimated matrix.

[0035] The fifth step is to use the MUSIC algorithm to calculate the number of incoming waves and their directions on the new estimated matrix.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A radio direction finding method based on a combination of virtual array elements and real array elements, characterized in that, The direction finding method employs a radio direction finding device based on a combination of virtual and real array elements. The direction finding device includes: N antennas evenly distributed on a planar circle and a multi-channel receiver. Each antenna consists of M array elements; M is greater than 3, and N is greater than 3. Among the M array elements, a virtual array element is arranged between two adjacent array elements. The direction finding method includes the following steps: The first step is to down-convert the signal received by each real array element and then perform weighted processing; using dimensional vector To represent the input data for each array, and to calculate the processed data. A two-dimensional matrix after the length of each data segment; The second step is to calculate the autocorrelation matrix of the input signal, and then calculate the eigenvalues ​​and corresponding eigenvectors of the autocorrelation matrix. The third step is to determine the number of incoming waves by the magnitude of the eigenvalues; if the number of incoming waves is less than M, the direction of incoming waves is calculated; if the number of incoming waves is equal to M, the sampled signal is processed to virtualize M array elements to obtain a new two-dimensional matrix. The fourth step is to calculate the autocorrelation matrix of the input signal, the eigenvalues ​​of the autocorrelation matrix, and the corresponding eigenvectors. If the autocorrelation matrix is ​​full rank, matrix decomposition is used, and spatial smoothing is employed to average the covariances of the decomposed submatrices to obtain the smoothed and corrected estimated matrix. The fifth step is to calculate the number of incoming waves and their directions for the new estimated matrix.

2. The radio direction finding method based on the combination of virtual array elements and real array elements as described in claim 1, characterized in that, In the first step, the signal received by each real array element is , The weighted output expression for each array element is: （1） use dimensional vector To represent the input data for each array, i.e.: （2） Then passed After the length of each data segment, the two-dimensional matrix becomes: （3）。 3. The radio direction finding method based on the combination of virtual array elements and real array elements as described in claim 2, characterized in that, In the second step, the autocorrelation matrix of the input signal is calculated. ,Right now ; The corresponding feature vector is .

4. The radio direction finding method based on the combination of virtual array elements and real array elements as described in claim 3, characterized in that, In the third step, if the number of incoming waves is less than M, the classical MUSIC algorithm is used to calculate the direction of arrival; if the number of incoming waves is equal to M, the sampled signal is further processed to create M virtual array elements, resulting in a total of 2M array elements and a new two-dimensional matrix. （4）。 5. The radio direction finding method based on the combination of virtual array elements and real array elements as described in claim 4, characterized in that, In the fourth step, the autocorrelation matrix of the input signal is calculated. ,Right now , The feature vector is .

6. The radio direction finding method based on the combination of virtual array elements and real array elements as described in claim 5, characterized in that, In the fifth step, the new estimation matrix is ​​calculated using the MUSIC algorithm to determine the number of incoming waves and their directions.

7. An application of the radio direction finding method based on the combination of virtual array elements and real array elements as described in any one of claims 1-6 in the field of radio direction finding technology.

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