Two-dimensional direction of arrival estimation method and device for augmented co-prime area array

Abstract

The invention discloses a two-dimensional direction-of-arrival estimation method and device for an augmented co-prime area array. The two-dimensional direction-of-arrival estimation method for the augmented co-prime area array comprises the following steps: constructing an augmented expanded co-prime array through two sub-area arrays; constructing a data model for the received signal, and performing eigenvalue decomposition on the data model to obtain a noise subspace; constructing a signal spatial spectrum function, performing preliminary direction-of-arrival estimation on the first sub-area array and the second sub-area array, performing two-dimensional search on the spatial spectrum function, finding a maximum peak coordinate, and obtaining an initial direction-of-arrival estimation value; based on the obtained initial DOA estimation value, accurate DOA estimation is carried out, and through ambiguity elimination calculation, an accurate DOA estimation value is obtained. The augmented and expanded co-prime array is constructed through the two sub-area arrays, and compared with the prior art, the array type improved by the embodiment of the invention reduces mutual coupling between array elements, and meanwhile, the degree of freedom of the co-prime array is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of array signal processing, and in particular to a two-dimensional direction-of-arrival estimation method and device for an augmented coprime array. Background Art

[0002] Coprime array signal processing technology was proposed in 2011. It uses two sparse arrays that meet the coprime condition to perform sparse sampling on the sound field signal. By reconstructing the autocorrelation to process the statistical signal, the direction of arrival of the source signal can be estimated. It is superior to coprime arrays such as nested arrays in terms of mutual coupling effect and closed-form solution. However, it still has the disadvantage of low continuous degrees of freedom of the data covariance matrix. Currently, most array signal processing algorithms, including subspace-based high-resolution direction-of-arrival estimation methods such as MUSIC and ESPRIT, are based on uniform linear or planar arrays. However, the element spacing of uniform arrays is generally required to be half a wavelength or less, which not only limits the array aperture but also the estimation degrees of freedom, and there is also the problem of mutual coupling between array element channels. Summary of the Invention

[0003] In view of the above problems, the present invention is proposed to provide a two-dimensional direction of arrival estimation method and device for an augmented coprime array that overcomes the above problems or at least partially solves the above problems.

[0004] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0005] According to a first aspect of an embodiment of the present invention, a two-dimensional direction of arrival estimation method for an augmented coprime array is provided, the two-dimensional direction of arrival estimation method for an augmented coprime array comprising: The augmented expanded coprime array is constructed by two sub-arrays, the two sub-arrays are the first sub-array L1 and the second sub-array L2, wherein the first sub-array L1 contains M x ×M y A uniform planar array of physical elements with spacing N in the x and y directions respectively. x and N y , the second sub-array L2 contains N x ×N y A uniform planar array of physical elements with a spacing of 2M in the x and y directions respectively x and 2M y , and M x and N x , M y and N y are relatively prime integers; Constructing a data model for the received signal, and performing eigenvalue decomposition on the data model to obtain a noise subspace; Constructing a signal spatial spectrum function, performing preliminary direction of arrival estimation on the first sub-array L1 and the second sub-array L2 respectively, performing a two-dimensional search on the spatial spectrum function to find the maximum peak coordinates, and obtaining an initial direction of arrival estimate; Based on the obtained initial DOA estimate, an accurate DOA estimate is performed, and an accurate DOA estimate is obtained through ambiguity elimination calculation.

[0006] In some embodiments of the present invention, the method comprises: The total number of physical elements contained in the augmented expanded coprime array is , and the first sub-array L1 and the second sub-array L2 overlap at the origin and are arranged separately in opposite directions; The element spacing of the i-th subarray is , , , , , d is the half wavelength of the incident signal; The set of element positions of the i-th sub-array is L=L1∪L2, where , .

[0007] In some embodiments of the present invention, constructing a data model for the received signal and performing eigenvalue decomposition on the data model to obtain a noise subspace includes: Assume that K come from The incoherent narrowband signal is incident on the augmented spread coprime array, where and are the elevation angle and azimuth angle corresponding to the kth signal, respectively, where K <min{ , }, ∈(0, 90°), ∈(0, 180°); Define the projection coefficients of the kth signal in the x and y directions as , ∈(-1, 1) and ∈(0,1); The received signal is defined as X i =A i S+N i , where S=[s1,s2,...,sk] T is the signal matrix, sk=[sk(1),sk(2),...sk(L)], L is the number of signal snapshots, Ni is additive Gaussian white noise with mean 0 and variance , A i is the direction matrix of the i-th submatrix, and , ,..., ], )and is the direction vector of the i-th sub-matrix in the x-direction and y-direction; Calculate the covariance matrix of the signal matrix , / L; For the covariance matrix Perform eigendecomposition to obtain , where E si is the signal subspace consisting of the eigenvectors corresponding to the K largest eigenvalues, D si is a diagonal matrix consisting of K largest eigenvalues, E ni is the noise subspace composed of the remaining eigenvectors except the K largest eigenvalues, D ni is a diagonal matrix consisting of all eigenvalues except the K largest eigenvalues.

[0008] In some embodiments of the present invention, obtaining an initial direction of arrival estimate includes: The spatial spectrum function of the constructed signal is , where the direction vector ; For the spatial spectrum function Perform a two-dimensional search to find the maximum peak coordinates and obtain the initial direction of arrival estimate ( ).

[0009] In some embodiments of the present invention, obtaining an accurate direction of arrival estimate includes: Assume that the angle ( ), there are two pairs of identical fuzzy values in the two sub-surface matrices, respectively ( ),( ); From the relationship between the true value and the fuzzy value, we can get: For the first sub-matrix, , ; For the second sub-matrix, , ; Then we get, , ,in, are all integers. When P1=P2=0, Q1=Q2=0, we get , ,but = = , = = , and obtain the true value, which is the accurate direction of arrival estimate after eliminating the ambiguity.

[0010] According to a second aspect of an embodiment of the present invention, a two-dimensional direction of arrival estimation device for an augmented coprime array is provided, the two-dimensional direction of arrival estimation device for an augmented coprime array comprising: The array construction unit is used to construct an augmented expanded coprime array through two sub-arrays, the two sub-arrays are the first sub-array L1 and the second sub-array L2, wherein the first sub-array L1 contains M x ×M y A uniform planar array of physical elements with spacing N in the x and y directions respectively. x and N y , the second sub-array L2 contains N x ×N y A uniform planar array of physical elements with a spacing of 2M in the x and y directions respectively x and 2M y , and M x and N x , M y and N y are relatively prime integers; an eigenvalue decomposition unit, configured to construct a data model for the received signal and perform eigenvalue decomposition on the data model to obtain a noise subspace; An initial direction of arrival estimation unit is configured to construct a signal spatial spectrum function, perform preliminary direction of arrival estimation on the first sub-array L1 and the second sub-array L2 respectively, perform a two-dimensional search on the spatial spectrum function, find the maximum peak coordinates, and obtain an initial direction of arrival estimate; The precise direction of arrival estimation unit is used to perform precise direction of arrival estimation based on the obtained initial direction of arrival estimation value, and obtain the precise direction of arrival estimation value through ambiguity elimination calculation.

[0011] In some embodiments of the present invention, the array construction unit is used to: The first sub-array L1 and the second sub-array L2 are overlapped at the origin and arranged separately in opposite directions, and the total number of physical array elements contained in the augmented expanded coprime array is ; The element spacing of the i-th subarray is , , , , , d is the half wavelength of the incident signal; The set of element positions of the i-th sub-array is L=L1∪L2, where , .

[0012] In some embodiments of the present invention, the eigenvalue decomposition unit constructs a data model for the received signal, and performs eigenvalue decomposition on the data model to obtain a noise subspace, including: Assume that K come from The incoherent narrowband signal is incident on the augmented spread coprime array, where and are the elevation angle and azimuth angle corresponding to the kth signal, respectively, where K <min{ , }, ∈(0, 90°), ∈(0, 180°); Define the projection coefficients of the kth signal in the x and y directions as , ∈(-1, 1) and ∈(0,1); The received signal is defined as X i =A i S+N i , where S=[s1,s2,...,sk] T is the signal matrix, sk=[sk(1),sk(2),...sk(L)], L is the number of signal snapshots, Ni is additive Gaussian white noise with mean 0 and variance , A i is the direction matrix of the i-th submatrix, and , ,..., ], )and is the direction vector of the i-th sub-matrix in the x-direction and y-direction; Calculate the covariance matrix of the signal matrix , / L; For the covariance matrix Perform eigendecomposition to obtain , where E si is the signal subspace consisting of the eigenvectors corresponding to the K largest eigenvalues, D si is a diagonal matrix consisting of K largest eigenvalues, E ni is the noise subspace composed of the remaining eigenvectors except the K largest eigenvalues, D ni is a diagonal matrix consisting of all eigenvalues except the K largest eigenvalues.

[0013] In some embodiments of the present invention, the initial arrival estimation unit obtaining the initial direction of arrival estimate value includes: The spatial spectrum function of the constructed signal is , where the direction vector ; For the spatial spectrum function Perform a two-dimensional search to find the maximum peak coordinates and obtain the initial direction of arrival estimate ( ).

[0014] In some embodiments of the present invention, the accurate arrival estimation unit obtaining an accurate arrival direction estimation value includes: Assume that the angle ( ), there are two pairs of identical fuzzy values in the two sub-surface matrices, respectively ( ),( ); From the relationship between the true value and the fuzzy value, we can get: For the first sub-matrix, , ; For the second sub-matrix, , ; Then we get, , ,in, are all integers. When P1=P2=0, Q1=Q2=0, we get , ,but = = , = = , and obtain the true value, which is the accurate direction of arrival estimate after eliminating the ambiguity.

[0015] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The two-dimensional direction of arrival estimation method and device for an augmented coprime array described in an embodiment of the present invention, the two-dimensional direction of arrival estimation method for an augmented coprime array described in an embodiment of the present invention constructs an augmented expanded coprime array through two sub-arrays, estimates the direction of arrival of the two sub-arrays separately, and then uses the characteristics of the coprime array to eliminate phase ambiguity to obtain an accurate direction of arrival estimate value. Compared with the existing technology, the improved array of the embodiment of the present invention reduces the mutual coupling between array elements and increases the degrees of freedom of the coprime array.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only 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.

[0018] Figure 1 A schematic flow chart of a two-dimensional direction-of-arrival estimation method for an augmented coprime array provided in an embodiment of the present invention; Figure 2 A reference diagram of the augmented expanded coprime array; Figure 3 Schematic diagram of the reference spatial spectrum image for two-dimensional direction of arrival estimation; Figure 4 Schematic diagram of scattered reference points for 2D DOA estimation; Figure 5 A schematic diagram showing the principle structure of a two-dimensional direction-of-arrival estimation device for an augmented coprime array provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described below in more detail with reference to the accompanying drawings.

[0020] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments of the present disclosure. These figures are not drawn to scale, and for the purpose of clarity, certain details are exaggerated and certain details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0021] In the context of this disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element or an intervening layer / element may exist therebetween. Additionally, if a layer / element is "on" another layer / element in one orientation, the layer / element may be "below" the other layer / element when the orientation is reversed. In the context of this disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0022] In order to better understand the above technical solution, the above technical solution will be described in detail below in combination with specific implementation methods. It should be understood that the embodiments of the present disclosure and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0023] Figure 1 FIG. 1 is a flow chart of a two-dimensional direction of arrival estimation method for an augmented coprime array provided by an embodiment of the present invention. Figure 1 As shown, the two-dimensional direction of arrival estimation method of the augmented coprime array includes the following steps: S1, construct an augmented expanded coprime array through two sub-arrays, the two sub-arrays are the first sub-array L1 and the second sub-array L2, wherein the first sub-array L1 contains M x ×M y A uniform planar array of physical elements with spacing N in the x and y directions respectively. x and N y , the second sub-array L2 contains N x ×N y A uniform planar array of physical elements with a spacing of 2M in the x and y directions respectively x and 2M y , and M x and N x , M y and N y are relatively prime integers; S2. constructing a data model for the received signal, and performing eigenvalue decomposition on the data model to obtain a noise subspace; S3. Construct a signal spatial spectrum function, perform preliminary direction of arrival estimation on the first sub-array L1 and the second sub-array L2 respectively, perform a two-dimensional search on the spatial spectrum function, find the maximum peak coordinates, and obtain an initial direction of arrival estimate; S4. Perform precise direction of arrival estimation based on the obtained initial direction of arrival estimation value, and obtain a precise direction of arrival estimation value through ambiguity elimination calculation.

[0024] Regarding step S1, combined Figure 2 As shown in FIG. 1 , a reference diagram of the augmented expanded coprime array is shown. In an embodiment of the present invention, the total number of physical array elements included in the augmented expanded coprime array is , and the first sub-array L1 (i.e., sub-array 1) and the second sub-array L2 (i.e., sub-array 2) overlap at the origin and are arranged separately in opposite directions; The element spacing of the i-th subarray is defined as , then , , , , where d is half the wavelength of the incident signal; The set of element positions of the i-th sub-array is L=L1∪L2, where , .

[0025] Regarding step S2, the embodiment of the present invention constructs a data model for the received signal and performs eigenvalue decomposition on the data model to obtain a noise subspace, specifically including: by = =2, = =3 array as an example, assuming K from The incoherent narrowband signal is incident on the augmented spread coprime array, where and are the elevation angle and azimuth angle corresponding to the kth signal, respectively, where K <min{ , }, ∈(0, 90°), ∈(0, 180°); The projection coefficients of the kth signal in the x-direction and y-direction are defined as ,in, ∈(-1, 1) and ∈(0,1); The received signal is defined as X i =A i S+N i , where S=[s1,s2,...,sk] T is the signal matrix, sk=[sk(1),sk(2),...sk(L)], L is the number of signal snapshots, Ni is additive Gaussian white noise with mean 0 and variance , A i is the direction matrix of the i-th submatrix, and , ,..., ], )and is the direction vector of the i-th sub-matrix in the x-direction and y-direction; then: ; ; ; ; Each element of the direction vector represents a certain array element.

[0026] Calculate the covariance matrix of the signal matrix , / L; Since the sampling number is performed under a limited number of snapshots, the embodiment of the present invention is to Perform eigendecomposition to obtain , where E siis the signal subspace consisting of the eigenvectors corresponding to the K largest eigenvalues, D si is a diagonal matrix consisting of K largest eigenvalues, E ni is the noise subspace composed of the remaining eigenvectors except the K largest eigenvalues, D ni is a diagonal matrix consisting of all eigenvalues except the K largest eigenvalues.

[0027] Regarding step S3, based on the characteristic that the noise subspace is orthogonal to the signal subspace, the embodiment of the present invention obtains an initial direction of arrival estimate including: The spatial spectrum function of the signal constructed by the embodiment of the present invention is: , where the direction vector ; For the spatial spectrum function Perform a two-dimensional search to find the maximum peak coordinates and obtain an initial direction of arrival estimate for the angular ambiguity ( ).

[0028] Regarding step S4, after obtaining the initial direction of arrival, performing a precise direction of arrival estimation based on the obtained initial direction of arrival estimate, the embodiment of the present invention obtains the precise direction of arrival estimate including: Since the spacing between array elements in a coprime array is greater than half a wavelength, angle ambiguity will occur. In this embodiment of the present invention, it is assumed that ( ) is the face array i from ( ), where t represents the true direction and a represents the estimate of t. Since the exponential function based on natural constants has a 2π periodicity, the relationship between the true value and the fuzzy value can be obtained:

[0029]

[0030] and Respectively represent the number of array elements in the x-direction and y-direction of array i, that is:

[0031]

[0032]

[0033]

[0034] and satisfy:

[0035]

[0036] In the embodiment of the present invention, it is assumed that the angle ( ), there are two pairs of identical fuzzy values in the two sub-surface matrices, respectively ( ),( ); According to the relationship between the true value and the fuzzy value above, we can get: For the first sub-matrix, , ; For the second sub-matrix, , ; Then we get, , ; in, are all integers. Since the sub-matrices are relatively prime, when P1=P2=0, Q1=Q2=0, we can get , ,but = = , = = For two mutually prime literal arrays, if there is only one pair of identical values for the true angle, the true value is obtained, which is the precise direction of arrival estimate after eliminating the ambiguity.

[0037] Combine Figure 2-4 As shown, = =2, = =3, the array structure when the number of array elements of the first sub-array L1 is expanded to a 4×4 sub-array, the number of detectable targets is 8. Assuming that there are eight far-field incoherent targets, they are (5°, 3°), (10°, 5°), (20°, 20°), (30°, 35°), (40°, 40°), (50°, 50°), (60°, 60°), and (70°, 75°). The horizontal axis is the pitch angle, ranging from [0, 90°], and the vertical axis is the azimuth angle, ranging from [0, 180°]. In this embodiment of the present invention, a spatial spectrum image of two-dimensional direction of arrival estimation can be obtained as follows: Figure 3 As shown in the reference, the corresponding two-dimensional direction of arrival estimation scattered reference diagram is as follows Figure 4 See reference.

[0038] The two-dimensional direction of arrival estimation method of the augmented coprime array described in the embodiment of the present invention constructs an augmented expanded coprime array by two sub-arrays, estimates the direction of arrival of the two sub-arrays respectively, and then eliminates phase ambiguity by using the characteristics of the coprime array to obtain an accurate direction of arrival estimate. The degree of freedom provided by the embodiment of the present invention depends on the array with a small number of array elements. When the number of array elements of the two sub-arrays is and When, assuming < , the number of detectable targets k1 <min{ , Improve the formation and expand the number of array elements of the first sub-array L1 to , the number of array elements of the two sub-arrays are and , the number of detectable targets k2 <min{p , }, that is, k2>k1, therefore, compared with the prior art, the improved array in the embodiment of the present invention reduces the mutual coupling between array elements and increases the degree of freedom of the coprime array.

[0039] On the basis of the above embodiment, as the above Figure 1 The present invention provides an embodiment of a two-dimensional direction of arrival estimation device for an augmented coprime array. Figure 1 The device can be applied to various electronic devices, see Figure 5 As shown, the two-dimensional direction of arrival estimation device of the augmented coprime array includes: The array construction unit 100 is used to construct an augmented expanded coprime array by using two sub-arrays, wherein the two sub-arrays are a first sub-array L1 and a second sub-array L2, wherein the first sub-array L1 includes M x ×M y A uniform planar array of physical elements with spacing N in the x and y directions respectively. x and N y , the second sub-array L2 contains N x ×N y A uniform planar array of physical elements with a spacing of 2M in the x and y directions respectively x and 2M y , and M x and N x , M y and N y are relatively prime integers; The eigenvalue decomposition unit 200 is used to construct a data model for the received signal and perform eigenvalue decomposition on the data model to obtain a noise subspace; An initial direction of arrival estimation unit 300 is configured to construct a signal spatial spectrum function, perform preliminary direction of arrival estimation on the first sub-array L1 and the second sub-array L2, respectively, perform a two-dimensional search on the spatial spectrum function to find the maximum peak coordinates, and obtain an initial direction of arrival estimate. The precise direction of arrival estimation unit 400 is configured to perform precise direction of arrival estimation based on the obtained initial direction of arrival estimation value, and obtain a precise direction of arrival estimation value through ambiguity elimination calculation.

[0040] In an embodiment of the present invention, the array construction unit 100 is used to: The first sub-array L1 and the second sub-array L2 are overlapped at the origin and arranged separately in opposite directions, and the total number of physical array elements contained in the augmented expanded coprime array is ; The element spacing of the i-th subarray is , , , , , d is the half wavelength of the incident signal; The set of element positions of the i-th sub-array is L=L1∪L2, where , .

[0041] In the embodiment of the present invention, the eigenvalue decomposition unit 200 constructs a data model for the received signal, and performs eigenvalue decomposition on the data model to obtain a noise subspace, including: Assume that K come from The incoherent narrowband signal is incident on the augmented spread coprime array, where and are the elevation angle and azimuth angle corresponding to the kth signal, respectively, where K <min{ , }, ∈(0, 90°), ∈(0, 180°); Define the projection coefficients of the kth signal in the x and y directions as , ∈(-1, 1) and ∈(0,1); The received signal is defined as X i =A i S+N i , where S=[s1,s2,...,sk] T is the signal matrix, sk=[sk(1),sk(2),...sk(L)], L is the number of signal snapshots, Ni is additive Gaussian white noise with mean 0 and variance , Ai is the direction matrix of the i-th submatrix, and , ,..., ], )and is the direction vector of the i-th sub-matrix in the x-direction and y-direction; Calculate the covariance matrix of the signal matrix , / L; For the covariance matrix Perform eigendecomposition to obtain , where E si is the signal subspace consisting of the eigenvectors corresponding to the K largest eigenvalues, D si is a diagonal matrix consisting of K largest eigenvalues, E ni is the noise subspace composed of the remaining eigenvectors except the K largest eigenvalues, D ni is a diagonal matrix consisting of all eigenvalues except the K largest eigenvalues.

[0042] In the embodiment of the present invention, the initial arrival estimation unit 300 obtains the initial arrival direction estimation value, including: The spatial spectrum function of the constructed signal is , where the direction vector ; For the spatial spectrum function Perform a two-dimensional search to find the maximum peak coordinates and obtain the initial direction of arrival estimate ( ).

[0043] In the embodiment of the present invention, the precise direction of arrival estimation unit 400 obtains a precise direction of arrival estimation value, including: Assume that the angle ( ), there are two pairs of identical fuzzy values in the two sub-surface matrices, respectively ( ),( ); From the relationship between the true value and the fuzzy value, we can get: For the first sub-matrix, , ; For the second sub-matrix, , ; Then we get, , ,in, are all integers. When P1=P2=0, Q1=Q2=0, we get , ,but = = , = = , and obtain the true value, which is the accurate direction of arrival estimate after eliminating the ambiguity.

[0044] The two-dimensional direction of arrival estimation device for an augmented coprime plane array described in an embodiment of the present invention can execute the two-dimensional direction of arrival estimation method for an augmented coprime plane array provided in the above embodiment. The two-dimensional direction of arrival estimation device for an augmented coprime plane array has the corresponding functional steps and beneficial effects of the two-dimensional direction of arrival estimation method for an augmented coprime plane array described in the above embodiment. For details, please refer to the embodiment of the two-dimensional direction of arrival estimation method for an augmented coprime plane array described in the above embodiment. The embodiment of the present invention will not be repeated here.

[0045] An embodiment of the present invention further provides an electronic device that may include a processor and a memory, wherein the processor and the memory may be connected via a bus or other means. The processor may be a central processing unit (CPU). The processor may also be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination of these chips. The memory, as a non-transitory computer-readable storage medium, may be used to store non-transitory software programs, non-transitory computer executable programs, and modules, such as the program instructions / modules corresponding to the two-dimensional direction of arrival estimation method for augmented coprime arrays in the embodiments of the present invention. The processor executes the non-transitory software programs, instructions, and modules stored in the memory to perform various processor functions and data processing, thereby implementing the two-dimensional direction of arrival estimation method for augmented coprime arrays in the above-mentioned method embodiments.

[0046] The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required by at least one function; the data storage area may store data created by the processor, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. The one or more modules are stored in the memory, and when executed by the processor, the two-dimensional direction of arrival estimation method of the augmented coprime array in the above-mentioned method embodiment is executed. The specific details of the above-mentioned electronic device can be understood by corresponding to the corresponding descriptions and effects in the above-mentioned method embodiment, and will not be repeated here. Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment method can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it may include the processes of the embodiments of the above-mentioned methods. The storage medium may be a read-only memory (ROM), a random access memory (RAM), a flash memory (Flash Memory), a hard disk drive (HDD) or a solid-state drive (SSD); the storage medium may also include a combination of the above types of memory.

[0047] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0048] Similarly, it should be understood that in order to streamline the present disclosure and aid understanding of one or more of the various inventive aspects, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Accordingly, the claims that follow the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the invention.

[0049] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims.

Claims

1. A two-dimensional direction of arrival estimation method for an augmented coprime array, characterized in that: The two-dimensional direction of arrival estimation method of the augmented coprime array includes: The augmented expanded coprime array is constructed by two sub-arrays, the two sub-arrays are the first sub-array L1 and the second sub-array L2, wherein the first sub-array L1 contains M x ×M y A uniform planar array of physical elements with spacing N in the x and y directions respectively. x and N y , the second sub-array L2 contains N x ×N y A uniform planar array of physical elements with a spacing of 2M in the x and y directions respectively x and 2M y , and M x and N x , M y and N y are relatively prime integers; Constructing a data model for the received signal, and performing eigenvalue decomposition on the data model to obtain a noise subspace; Constructing a signal spatial spectrum function, performing preliminary direction of arrival estimation on the first sub-array L1 and the second sub-array L2 respectively, performing a two-dimensional search on the spatial spectrum function to find the maximum peak coordinates, and obtaining an initial direction of arrival estimate; Based on the obtained initial DOA estimate, an accurate DOA estimate is performed, and an accurate DOA estimate is obtained through ambiguity elimination calculation.

2. The two-dimensional direction of arrival estimation method for an augmented coprime array according to claim 1, characterized in that: The method comprises: The total number of physical elements contained in the augmented expanded coprime array is , and the first sub-array L1 and the second sub-array L2 overlap at the origin and are arranged separately in opposite directions; The element spacing of the i-th subarray is , , , , , d is the half wavelength of the incident signal; The set of element positions of the i-th sub-array is L=L1∪L2, where , .

3. The two-dimensional direction of arrival estimation method of the augmented coprime array according to claim 1, characterized in that: The step of constructing a data model for the received signal and performing eigenvalue decomposition on the data model to obtain a noise subspace includes: Assume that K come from The incoherent narrowband signal is incident on the augmented spread coprime array, where and are the elevation angle and azimuth angle corresponding to the kth signal, respectively, where K <min{ , }, ∈(0, 90°), ∈(0, 180°); Define the projection coefficients of the kth signal in the x and y directions as , ∈(-1, 1) and ∈(0,1); The received signal is defined as X i =A i S+N i , where S=[s1,s2,...,sk] T is the signal matrix, sk=[sk(1),sk(2),...sk(L)], L is the number of signal snapshots, Ni is additive Gaussian white noise with mean 0 and variance , A i is the direction matrix of the i-th submatrix, and , ,..., ], )and is the direction vector of the i-th sub-matrix in the x-direction and y-direction; Calculate the covariance matrix of the signal matrix , / L; For the covariance matrix Perform eigendecomposition to obtain , where E si is the signal subspace consisting of the eigenvectors corresponding to the K largest eigenvalues, D si is a diagonal matrix consisting of K largest eigenvalues, E ni is the noise subspace composed of the remaining eigenvectors except the K largest eigenvalues, D ni is a diagonal matrix consisting of all eigenvalues except the K largest eigenvalues.

4. The two-dimensional direction of arrival estimation method of the augmented coprime array according to claim 3, characterized in that: Obtaining an initial direction of arrival estimate includes: The spatial spectrum function of the constructed signal is , where the direction vector ; For the spatial spectrum function Perform a two-dimensional search to find the coordinates of the maximum peak and obtain an initial direction of arrival estimate.

5. The two-dimensional direction of arrival estimation method of the augmented coprime array according to claim 4, characterized in that: Obtaining an accurate direction of arrival estimate includes: Assume that the angle ( ), there are two pairs of identical fuzzy values in the two sub-surface matrices, respectively ( ),( ); From the relationship between the true value and the fuzzy value, we can get: For the first sub-matrix, , ; For the second sub-matrix, , ; Then we get, , ,in, are all integers. When P1=P2=0, Q1=Q2=0, we get , ,but = = , = = , and obtain the true value, which is the accurate direction of arrival estimate after eliminating the ambiguity.

6. A two-dimensional direction of arrival estimation device for an augmented coprime array, characterized in that: The two-dimensional direction of arrival estimation device of the augmented coprime array comprises: The array construction unit is used to construct an augmented expanded coprime array through two sub-arrays, the two sub-arrays are the first sub-array L1 and the second sub-array L2, wherein the first sub-array L1 contains M x ×M y A uniform planar array of physical elements with spacing N in the x and y directions respectively. x and N y , the second sub-array L2 contains N x ×N y A uniform planar array of physical elements with a spacing of 2M in the x and y directions respectively x and 2M y , and M x and N x , M y and N y are relatively prime integers; an eigenvalue decomposition unit, configured to construct a data model for the received signal and perform eigenvalue decomposition on the data model to obtain a noise subspace; An initial direction of arrival estimation unit is configured to construct a signal spatial spectrum function, perform preliminary direction of arrival estimation on the first sub-array L1 and the second sub-array L2 respectively, perform a two-dimensional search on the spatial spectrum function, find the maximum peak coordinates, and obtain an initial direction of arrival estimate; The precise direction of arrival estimation unit is used to perform precise direction of arrival estimation based on the obtained initial direction of arrival estimation value, and obtain the precise direction of arrival estimation value through ambiguity elimination calculation.

7. The two-dimensional direction of arrival estimation device for augmented coprime array according to claim 6, characterized in that: The array building unit is used for: The first sub-array L1 and the second sub-array L2 are overlapped at the origin and arranged separately in opposite directions, and the total number of physical array elements contained in the augmented expanded coprime array is ; The element spacing of the i-th subarray is , , , , , d is the half wavelength of the incident signal; The set of element positions of the i-th sub-array is L=L1∪L2, where , .

8. The two-dimensional direction of arrival estimation device for augmented coprime array according to claim 6, characterized in that: The eigenvalue decomposition unit constructs a data model for the received signal, and performs eigenvalue decomposition on the data model to obtain a noise subspace, including: Assume that K come from The incoherent narrowband signal is incident on the augmented spread coprime array, where and are the elevation angle and azimuth angle corresponding to the kth signal, respectively, where K <min{ , }, ∈(0, 90°), ∈(0, 180°); Define the projection coefficients of the kth signal in the x and y directions as , ∈(-1, 1) and ∈(0,1); The received signal is defined as X i =A i S+N i , where S=[s1,s2,...,sk] T is the signal matrix, sk=[sk(1),sk(2),...sk(L)], L is the number of signal snapshots, Ni is additive Gaussian white noise with mean 0 and variance , A i is the direction matrix of the i-th submatrix, and , ,..., ], )and is the direction vector of the i-th sub-matrix in the x-direction and y-direction; Calculate the covariance matrix of the signal matrix , / L; For the covariance matrix Perform eigendecomposition to obtain , where E si is the signal subspace consisting of the eigenvectors corresponding to the K largest eigenvalues, D si is a diagonal matrix consisting of K largest eigenvalues, E ni is the noise subspace composed of the remaining eigenvectors except the K largest eigenvalues, D ni is a diagonal matrix consisting of all eigenvalues except the K largest eigenvalues.

9. The two-dimensional direction of arrival estimation device for augmented coprime array according to claim 8, characterized in that: The initial arrival estimation unit obtaining the initial arrival direction estimation value includes: The spatial spectrum function of the constructed signal is , where the direction vector ; For the spatial spectrum function Perform a two-dimensional search to find the coordinates of the maximum peak and obtain an initial direction of arrival estimate.

10. The two-dimensional direction of arrival estimation device for augmented coprime array according to claim 9, characterized in that: The accurate arrival direction estimation unit obtains an accurate arrival direction estimation value, including: Assume that the angle ( ), there are two pairs of identical fuzzy values in the two sub-surface matrices, respectively ( ),( ); From the relationship between the true value and the fuzzy value, we can get: For the first sub-matrix, , ; For the second sub-matrix, , ; Then we get, , ,in, are all integers. When P1=P2=0, Q1=Q2=0, we get , ,but = = , = = , and obtain the true value, which is the accurate direction of arrival estimate after eliminating the ambiguity.

Images