A sparse array group array method based on three uniform linear array cascades and application

Abstract

The application discloses a sparse array group array method based on three uniform linear array cascades and application, utilizes three uniform linear array group arrays, reduces mutual coupling influence by setting large subarray element spacing, and can obtain a large-aperture virtual uniform linear antenna array by setting reasonable subarray spacing, and then high-precision DOA estimation without ambiguity can be completed. The application improves the element positions of three subarrays in the existing three uniform linear array cascade, constructs a low mutual coupling array based on three uniform linear array cascades, realizes the optimization target that the element weight values of elements smaller than the subarray element spacing in the difference set are 1, effectively improves the mutual coupling leakage phenomenon existing between the elements of the existing sparse array, guarantees the low mutual coupling, and guarantees the continuous virtual array aperture. Under the condition of strong mutual coupling, the array pattern can obtain the highest DOA estimation precision, meanwhile, with the increase of the mutual coupling strength, the array pattern has good robustness.

Description

Technical Field

[0001] This invention belongs to the field of electronic communication technology, and particularly relates to a sparse array assembly method and its application based on the cascading of three uniform linear arrays. Background Technology

[0002] Array-based Direction of Arrival (DOA) estimation techniques, using subspace algorithms, can achieve super-resolution estimation results. Currently, uniform linear arrays are widely used. To obtain unambiguous angle estimates, the spacing between antenna elements is typically set to no more than half the wavelength of the incident signal. With the development of new communication technologies, the demand for DOA estimation accuracy is increasing. However, uniform linear arrays often only improve accuracy by increasing the number of elements to increase the array aperture, but this also increases the hardware complexity of the equipment, and small element spacing introduces mutual coupling interference, degrading DOA estimation performance. Therefore, considering the design of sparse arrays with element spacing greater than half the wavelength to achieve high-precision, unambiguous, and low-mutual-coupling DOA estimation has become a research hotspot in wireless communication.

[0003] The current main idea behind sparse antenna array design is to achieve unambiguous and high-precision DOA estimation by mapping the physical antenna array to a large-aperture virtual uniform linear array. However, existing sparse arrays, in order to achieve a large-aperture virtual array, have multiple small element spacings between different array elements. When the mutual coupling interference between antennas is strong, the DOA estimation accuracy deteriorates significantly. Summary of the Invention

[0004] To address the problem that existing sparse arrays, in order to achieve a large-aperture virtual array, have multiple small element spacings between different array elements, and that DOA estimation accuracy deteriorates significantly when there is strong mutual coupling interference between antennas, this invention proposes a sparse array assembly method and application based on the cascaded arrangement of three uniform linear arrays. By assembling three uniform linear arrays and reducing mutual coupling effects by setting large subarray element spacing, and by setting reasonable subarray spacing, a large-aperture virtual uniform linear antenna array can be obtained, thereby achieving unambiguous and high-precision DOA estimation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention proposes a sparse array assembly method based on the cascaded arrangement of three uniform linear arrays, comprising:

[0007] Three antenna subarrays are set up, namely the first subarray, the second subarray, and the third subarray. The first subarray is a uniform linear array with M1 array elements and a subarray spacing of d1. The second subarray is a uniform linear array with M2 array elements and a subarray spacing of d2. The third subarray is a uniform linear array with M3 array elements and a subarray spacing of d3. The spacing between the first element of the second subarray and the first element of the first subarray is L1, and the spacing between the first element of the third subarray and the first element of the first subarray is L2.

[0008] Furthermore, the array element positions of the three antenna subarrays are as follows:

[0009]

[0010] in, Let m1, m2, and m3 represent the first subarray, the second subarray, and the third subarray, respectively, where m1, m2, and m3 are integers.

[0011] Furthermore, when the total number of array elements M = M1 + M2 + M3 is fixed, the array-related parameters are set as follows:

[0012]

[0013] in, r and β are intermediate parameters defined to simplify the formula. represents rounding down and rounding up respectively; d represents the basic unit of subarray element spacing.

[0014] In another aspect, this invention proposes the application of a sparse array composed of three antenna subarrays derived from any of the sparse array grouping methods based on the cascaded three uniform linear arrays in DOA estimation.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention improves the element positions of the three subarrays in existing cascaded three uniform linear arrays by constructing a low-coupling array based on cascaded three uniform linear arrays. It achieves the optimization objective of having elements in the difference set with a weight of 1 that is smaller than the element spacing of the subarrays, effectively mitigating the mutual coupling leakage phenomenon existing in existing sparse arrays. While ensuring low mutual coupling, it also guarantees a continuous virtual array aperture. Under strong mutual coupling conditions, the array configuration of this invention achieves the highest DOA estimation accuracy, and exhibits good robustness as the mutual coupling strength increases. Attached Figure Description

[0017] Figure 1 This is a diagram of an antenna array structure constructed based on a sparse array grouping method of three uniform linear arrays according to an embodiment of the present invention.

[0018] Figure 2 This is a weight function distribution diagram according to an embodiment of the present invention;

[0019] Figure 3 This is a graph showing the trend of mutual coupling leakage values ​​under different intensities of mutual coupling interference according to an embodiment of the present invention.

[0020] Figure 4 This is a flowchart illustrating the key steps in applying the embodiments of the present invention. Detailed Implementation

[0021] For ease of understanding, the following explanations are provided for some of the terms used in the specific embodiments of this invention:

[0022] Direction of Arrival (DOA) estimation: A processing system consisting of a space multi-sensor array estimates various parameters of a space signal of interest.

[0023] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments:

[0024] This invention provides a sparse array assembly method based on the cascaded arrangement of three uniform linear arrays, and the constructed array structure is as follows: Figure 1 As shown, subarray 1 is a uniform linear array with M1 elements and a subarray spacing of d1. Subarray 2 is a uniform linear array with M2 elements and a subarray spacing of d2. Subarray 3 is a uniform linear array with M3 elements and a subarray spacing of d3. The distance between the first element of subarray 2 and the first element of subarray 1 is L1, and the distance between the first element of subarray 3 and the first element of subarray 1 is L2. Therefore, the array element positions of this invention are...

[0025]

[0026] in, Let m1, m2, and m3 represent the first subarray, the second subarray, and the third subarray, respectively, where m1, m2, and m3 are integers.

[0027] When the total number of array elements M = M1 + M2 + M3 is fixed, the definition is... in Let r and β represent rounding down and rounding up, respectively. Since r and β are intermediate parameters defined for simplifying the formula, the array-related parameters are set as follows:

[0028]

[0029] Where d represents the basic unit of subarray element spacing.

[0030] To verify the effectiveness of this invention, the following evidence is presented:

[0031] 1. Construct a virtual uniform linear array with a large aperture, where the number of virtual array elements is much greater than the number of physical array elements.

[0032] Define physical array With virtual array The mapping relationship is

[0033]

[0034] Assuming the number of array elements is M = 16 and d = 1, then

[0035]

[0036] thus A continuous array of elements from -75 to 75 can be obtained, thereby constructing a virtual linear array of 151 elements. The number of virtual elements is much greater than the number of physical elements, and the constructed array has a larger aperture than a uniform linear array.

[0037] 2. Subarrays with large element spacing ensure strong anti-mutual interference capability and low mutual leakage value. To quantitatively measure the impact of mutual interference, a widely accepted quantitative standard is given. First, define... The weight function w(l):

[0038]

[0039] Where <·> indicates that the value l is in the set The number of elements in the array.

[0040] Then, define a mutual coupling matrix C, which is an M×M matrix, where the element in the m-th row and n-th column of C can be represented as:

[0041]

[0042] And c0 = 1 > |c1| > ... |c B |

[0043] Redefining mutual coupling leakage L e Its expression is:

[0044] L e =||C-diag(C)|| F / ||C|| F

[0045] Where diag(C) denotes the construction of a diagonal matrix whose diagonal elements are the diagonal elements of C, ||·|| FLet w(l) denote the Frobenius norm of a matrix. The lower the mutual coupling leakage value, the less the array is affected by mutual coupling. Furthermore, according to the definition of the mutual coupling matrix, when l ≤ B, the smaller the value of w(l), the lower the F-norm value of C, and the lower the mutual coupling leakage will be.

[0046] Similarly, assuming the number of array elements is M = 16, d = 1, and B = 3, the weight distribution is as follows: Figure 2 As shown. Figure 2 The value of the spacing between small array elements is 1, and the weight function obtains the optimal solution.

[0047] If c1 = ce jπ / 6 ,c b =c1e -jπ(b-1) / 6 / b, then the mutual coupling leakage value changes with c as shown in the figure. Figure 3 As shown, compared to a standard uniform linear array, the mutual coupling leakage value of this invention remains within a lower range as the mutual coupling strength increases.

[0048] Based on the above embodiments, this invention also proposes the application of a sparse array composed of three antenna subarrays obtained from any of the sparse array grouping methods based on the cascaded three uniform linear arrays in DOA estimation. The key application steps are as follows: Figure 4 As shown.

[0049] In summary, this invention improves the element positions of the three subarrays in existing cascaded three uniform linear arrays, constructing a low-coupling array based on cascaded three uniform linear arrays. It achieves the optimization objective of having elements in the difference set with a weight of 1 that is smaller than the element spacing of the subarrays, effectively mitigating the mutual coupling leakage phenomenon existing in existing sparse arrays. While ensuring low mutual coupling, it also guarantees a continuous virtual array aperture. Under strong mutual coupling conditions, the array configuration of this invention achieves the highest DOA estimation accuracy, and exhibits good robustness as the mutual coupling strength increases.

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle 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 sparse array group array method based on three uniform linear array cascades, characterized in that, Comprising: Three antenna subarrays are arranged, which are a first subarray, a second subarray and a third subarray, wherein the first subarray is a uniform linear array with array elements and subarray intervals of , the second subarray is a uniform linear array with array elements and subarray intervals of , and the third subarray is a uniform linear array with array elements and subarray intervals of ; the interval between the first array element of the second subarray and the first array element of the first subarray is , and the interval between the first array element of the third subarray and the first array element of the first subarray is ; The array element positions of the three antenna sub-arrays are : wherein , , respectively represent a first subarray array, a second subarray array, a third subarray array, is an integer; When the total number of array elements When the array is fixed, the array-related parameters are set as follows: wherein , , , intermediate parameters defined for simplifying the formula, respectively denote the floor and ceiling functions; denotes a basic unit of the subarray element spacing.

2. The use of a sparse array consisting of three antenna sub-arrays derived from a sparse array group array method based on a cascade of three uniform linear array sub-arrays according to claim 1 in DOA estimation.

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