A robust adaptive beamforming method and device based on main lobe shape preserving

Abstract

The application provides a main-lobe shape-preserving-based robust adaptive beamforming method and device, and the method comprises the following steps: receiving echo data by using a radar, determining a received echo covariance matrix based on the echo data; processing the received echo covariance matrix by using a diagonal loading technology to obtain a loaded covariance matrix; determining an optimal loading amount by using a pre-configured optimal loading amount calculation model; determining an adaptive weight after loading by using the optimal loading amount; and obtaining an adaptive receiving directivity diagram by using the adaptive weight after loading. The embodiment of the application can be used for realizing robust adaptive beamforming when multiple non-coherent target signals exist in a main-lobe region at the same time, can make the obtained adaptive receiving directivity diagram not form a null in the direction of any target signal in the main-lobe region, ensures the integrity of the main-lobe region, and thus improves the alerting and detecting performance of the radar system on the target signal.

Description

Technical Field

[0001] This invention relates to the field of radar target detection technology, and in particular to a robust adaptive beamforming method and apparatus based on main lobe conformal. Background Technology

[0002] When multiple incoherent signals with very close angles, caused by local spatial scattering, are simultaneously incident on the receiving antenna, multiple target signals enter the radar receiver from the main lobe region. In this case, the weights calculated using the adaptive beamforming method will cause the main lobe of the adaptive beamforming pattern to point towards the direction of one of the target signals, while creating nulls in the directions of other target signals. These target signals are then suppressed as interference signals, resulting in severe distortion of the main lobe of the adaptive receiving pattern, thereby weakening the radar system's early warning and detection capabilities.

[0003] However, most existing robust adaptive beamforming methods are only applicable when the received echo contains only a single target signal. Although the adaptive beamforming method proposed in the paper "Robust adaptive beamforming in sensor arrays" can reduce the impact of local spatial scattering on the adaptive beamformer, it requires precise knowledge of the target signal covariance matrix and the interference plus noise covariance matrix, which are often difficult to determine in practical applications.

[0004] Therefore, how to achieve a robust adaptive beamforming method when multiple incoherent target signals exist simultaneously in the main lobe region has always been a focus of relevant researchers. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to achieve robust adaptive beamforming when multiple incoherent target signals exist simultaneously in the main lobe region; in view of this, the present invention provides a robust adaptive beamforming method and apparatus based on main lobe conformal.

[0006] The technical solution adopted in this invention is a robust adaptive beamforming method based on main lobe conformal, comprising:

[0007] Step S1: Utilize radar to receive echo data and determine the received echo covariance matrix based on the echo data;

[0008] Step S2: Process the received echo covariance matrix using diagonal loading technology to obtain the loading covariance matrix;

[0009] Step S3: Determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while ensuring that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value.

[0010] Step S4: Using the optimal loading amount, determine the adaptive weight after loading;

[0011] Step S5: Using the loaded adaptive weights, obtain the adaptive receiving pattern.

[0012] In one embodiment, the step of utilizing radar received echo data and determining the received echo covariance matrix based on the echo data includes:

[0013] Using the radar echo data X(t), the received echo covariance matrix R is obtained. X :

[0014]

[0015] Among them, X(t)=AS(t)+n(t), S(t)=[s p1 (t) s p2 (t) s1(t) s2(t) ··· s Q (t)] T Let A = [a(θ)] be the complex envelope of two target signals and Q interference signals at time t, and the complex envelopes of the target signals and interference signals are uncorrelated. p1 ) a(θ p2 ) a(θ1) a(θ2) ··· a(θ Q )] is the array manifold matrix corresponding to all signals, θ p1 and θ p2 Let θ1, θ2, ... θ be the angles of the two target signals. Q Let Q be the angles of the interfering signals, and a(θ) = [1 e j2πdsinθ / λ e j2π(L-1)dsinθ / λ ] T For the array guiding vector, (·) T For the transpose operation, (·) H For the conjugate transpose operation, L is the number of antenna elements, d is the spacing between antenna elements, λ is the operating wavelength, and n(t) = [n1(t) n2(t) ··· n L (t)] T This represents the Gaussian white noise received by all antenna elements, with a mean of 0 and a variance of . And it is uncorrelated with all signals. and R represents the power of the two target signals.in The noise covariance matrix is ​​the interference plus noise.

[0016] In one embodiment, processing the received echo covariance matrix using a diagonal loading technique to obtain a loaded covariance matrix includes:

[0017] Using diagonal loading technology to dock and recover the wave covariance matrix R X Processing is performed to obtain the loaded covariance matrix.

[0018]

[0019] Where ρ is the loading amount and I is the identity matrix.

[0020] In one implementation, determining the optimal loading amount using a pre-configured optimal loading amount calculation model includes:

[0021] The calculation model is configured based on the criterion of maximizing the output signal-to-interference-plus-noise ratio (SINR) of one target signal while ensuring that the SINR of the other target signal is not less than a certain value.

[0022] max SINR p2

[0023] stSINR p1 ≥η

[0024] Where η is the threshold,

[0025]

[0026] The output signal-to-interference-plus-noise ratio of the first target signal.

[0027]

[0028] Let a be the output signal-to-interference-plus-noise ratio of the second target signal. p1 =a(θ) p1 ), a p2 =a(θ) p2 );

[0029] The interference plus noise covariance matrix R in Perform eigenvalue decomposition to obtain the eigenvector matrix U corresponding to the interference subspace. i The eigenvector matrix U corresponding to the noise subspace n ;

[0030] Based on the Lagrange multiplier method, a quadratic function with respect to the loading factor is determined;

[0031] Using the quadratic function, determine the expression for the optimal loading amount in the loading factor;

[0032] The value of the Lagrange factor in the expression is determined by using a cyclic iterative method, thereby determining the optimal loading amount.

[0033] In one implementation, the optimal loading amount is used to determine the adaptive weight after loading, specifically determined by the following formula:

[0034]

[0035] Where, ρ opt To achieve the optimal load, These are the adaptive weights after loading.

[0036] In one implementation, obtaining the adaptive reception pattern using the loaded adaptive weights includes:

[0037]

[0038] Where θ is the scanning angle.

[0039] Another aspect of the present invention provides a robust adaptive beamforming device based on main lobe conformal, comprising:

[0040] The acquisition unit is configured to receive echo data using radar and determine the received echo covariance matrix based on the echo data.

[0041] The diagonal loading unit is configured to process the received echo covariance matrix using diagonal loading technology to obtain the loading covariance matrix.

[0042] The optimal loading unit is configured to determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while satisfying the condition that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value.

[0043] An adaptive weighting unit is configured to determine the adaptive weights after loading using the optimal loading amount;

[0044] An adaptive receiving pattern unit is configured to obtain an adaptive receiving pattern using the loaded adaptive weights.

[0045] Another aspect of the present invention provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the robust adaptive beamforming method based on main lobe conformal as described in any of the preceding claims.

[0046] Another aspect of the present invention provides a computer storage medium storing a computer program that, when executed by a processor, implements the steps of the robust adaptive beamforming method based on main lobe conformal as described in any of the preceding claims.

[0047] Compared with the prior art, the present invention has at least the following advantages:

[0048] The robust adaptive beamforming method based on main lobe conformance provided by this invention ensures that the obtained adaptive receiver pattern does not form nulls in the direction of any target signal within the main lobe region, thus ensuring the integrity of the main lobe region and improving the radar system's early warning and detection performance for target signals. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the robust adaptive beamforming method based on main lobe conformance according to an embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of the composition of a robust adaptive beamforming device based on main lobe conformance according to an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of the electronic device according to an embodiment of the present invention. Detailed Implementation

[0052] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0053] In the accompanying drawings, the thickness, size, and shape of the objects have been slightly exaggerated for ease of illustration. The drawings are for illustrative purposes only and are not drawn to scale.

[0054] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed feature, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0055] As used herein, the terms “basically,” “approximately,” and similar terms are used as terms of approximation rather than terms of degree, and are intended to describe inherent biases in measured or calculated values ​​that will be recognized by those skilled in the art.

[0056] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0058] In the first embodiment of the present invention, a robust adaptive beamforming method based on main lobe conformal is provided, such as... Figure 1 As shown, it includes:

[0059] Step S1: Utilize radar to receive echo data and determine the received echo covariance matrix based on the echo data;

[0060] Step S2: The diagonal loading technique is used to process the resonant covariance matrix to obtain the loading covariance matrix.

[0061] Step S3: Determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while ensuring that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value.

[0062] Step S4: Determine the adaptive weights after loading using the optimal loading amount;

[0063] Step S5: Using the loaded adaptive weights, obtain the adaptive receiving pattern.

[0064] The embodiments provided by the present invention will be described in detail step by step below.

[0065] This invention is based on a one-dimensional equidistant phased array radar system. For target detection when multiple incoherent target signals exist simultaneously in the main lobe region, a robust adaptive beamforming method based on main lobe conformity is proposed.

[0066] Step S1: Use radar to receive echo data and obtain the received echo covariance matrix.

[0067] Using the radar echo data X(t), the received echo covariance matrix R is obtained. X .

[0068]

[0069] Among them, X(t)=AS(t)+n(t), S(t)=[s p1 (t) s p2 (t) s1(t) s2(t) ··· s Q (t)] T Let A = [a(θ)] be the complex envelope of two target signals and Q interference signals at time t, and the complex envelopes of the target signals and interference signals are uncorrelated. p1 ) a(θ p2 ) a(θ1) a(θ2) ··· a(θ Q )] is the array manifold matrix corresponding to all signals, θ p1 and θ p2 Let θ1, θ2, ... θ be the angles of the two target signals. Q Let Q be the angles of the interfering signals, and a(θ) = [1 e j2πdsinθ / λ e j2π(L-1)dsinθ / λ ] T For the array guiding vector, (·) T For the transpose operation, (·) H For the conjugate transpose operation, L is the number of antenna elements, d is the spacing between antenna elements, λ is the operating wavelength, and n(t) = [n1(t) n2(t) ··· n L (t)] T This represents the Gaussian white noise received by all antenna elements, with a mean of 0 and a variance of . And it is uncorrelated with all signals. and R represents the power of the two target signals. in The noise covariance matrix is ​​the interference plus noise.

[0070] Step S2: Use diagonal loading technology to process the resonant covariance matrix to obtain the loading covariance matrix.

[0071] The diagonal loading technique was used to process the covariance matrix of the recovered wave. X Obtain the loaded covariance matrix

[0072]

[0073] Where ρ is the loading amount and I is the identity matrix.

[0074] Step S3: Determine the optimal loading amount by establishing a model that maximizes the output signal-to-interference-plus-noise ratio (SIR) of one target signal while ensuring that the SIR of the other target signal is not less than a certain value.

[0075] (1) An optimization model is established based on the criterion of maximizing the output signal-to-interference-plus-noise ratio of the other target signal while satisfying that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value.

[0076] max SINR p2

[0077] stSINR p1 ≥η

[0078] Where η is the threshold,

[0079]

[0080] The output signal-to-interference-plus-noise ratio of target signal 1.

[0081]

[0082] Let a be the output signal-to-interference-plus-noise ratio of the target signal 2. p1 =a(θ) p1 ), a p2 =a(θ) p2 ).

[0083] (2) The interference plus noise covariance matrix R in Perform eigenvalue decomposition to obtain the eigenvector matrix U corresponding to the interference subspace. i The eigenvector matrix U corresponding to the noise subspace n .

[0084]

[0085] Among them, Λ=diag[λ1 λ2 ... λ L [ ] is a diagonal matrix consisting of all eigenvalues ​​and U = [u1 u2 … u] L ] represents the characteristic vector matrix, Λ i =diag[λ1 λ2 … λ Q ] is a diagonal matrix composed of interference eigenvalues, Λ n =diag[λ Q+1 λ Q+2 … λ L ] is a diagonal matrix composed of noise eigenvalues, U i =[u1 u2 … u Q ] and U n =[u Q+1 uQ+2 … u L ] are the eigenvector matrices corresponding to the interference subspace and the noise subspace, respectively.

[0086] (3) Solve the optimization problem using the Lagrange multiplier method.

[0087] H(ρ)=-SINR p2 +g(η-SINR p1 )

[0088] Where g is the Lagrange factor.

[0089] (4) Since H(ρ) is a quadratic function of the loading factor ρ, the optimal loading amount ρ can be determined by the fact that the first derivative of H(ρ) with respect to ρ is equal to 0. opt The expression.

[0090]

[0091]

[0092]

[0093]

[0094] Among them, SNR p1 Let SNR be the input signal-to-noise ratio of target signal 1. p2 The input signal-to-noise ratio of target signal 2,

[0095] (4) Use the iterative method to obtain the value of the Lagrange factor g.

[0096] Step S4: Use the calculated optimal loading amount to obtain the adaptive weights after loading.

[0097] Using the calculated optimal loading amount ρ opt Obtain the adaptive weights after loading.

[0098]

[0099] Step S5: Obtain the adaptive receiving pattern using the loaded adaptive weights.

[0100] Utilizing the adaptive weights after loading Obtain the adaptive receiver pattern F(θ).

[0101]

[0102] Where θ is the scanning angle.

[0103] The second embodiment of the present invention, corresponding to the first embodiment, introduces a robust adaptive beamforming method and apparatus based on main lobe conformal, such as... Figure 2 As shown, it includes the following components:

[0104] The acquisition unit is configured to receive echo data using radar and determine the received echo covariance matrix based on the echo data.

[0105] The diagonal loading unit is configured to process the received echo covariance matrix using diagonal loading technology to obtain the loading covariance matrix.

[0106] The optimal loading unit is configured to determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while satisfying the condition that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value.

[0107] An adaptive weighting unit is configured to determine the adaptive weights after loading using the optimal loading amount;

[0108] An adaptive receiving pattern unit is configured to obtain an adaptive receiving pattern using the loaded adaptive weights.

[0109] A third embodiment of the present invention provides an electronic device, such as... Figure 3 As shown, it can be understood as a physical device, including a processor and a memory storing processor-executable instructions, which, when executed by the processor, perform the following operations:

[0110] Step S1: Utilize radar to receive echo data and determine the received echo covariance matrix based on the echo data;

[0111] Step S2: The diagonal loading technique is used to process the resonant covariance matrix to obtain the loading covariance matrix.

[0112] Step S3: Determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while ensuring that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value.

[0113] Step S4: Determine the adaptive weights after loading using the optimal loading amount;

[0114] Step S5: Using the loaded adaptive weights, obtain the adaptive receiving pattern.

[0115] In the fourth embodiment of the present invention, the process of the base station's inter-cell cooperative scheduling method is the same as that of the first, second, or third embodiments. The difference lies in the engineering implementation: this embodiment can be implemented using software plus necessary general-purpose hardware platforms. While hardware implementation is also possible, the former is often a better approach. Based on this understanding, the robust adaptive beamforming method based on main lobe conformance of the present invention can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a device to execute the method described in the embodiments of the present invention.

[0116] In summary, compared with the prior art, the robust adaptive beamforming method based on main lobe conformance provided by this invention ensures that the obtained adaptive receiving pattern does not form nulls in any direction of the target signal within the main lobe region, thus ensuring the integrity of the main lobe region and improving the radar system's early warning and detection performance for target signals.

[0117] Through the description of specific embodiments, a more in-depth and specific understanding should be gained of the technical means and effects adopted by the present invention to achieve the intended purpose. However, the accompanying drawings are only provided for reference and illustration and are not intended to limit the present invention.

Claims

1. A robust adaptive beamforming method based on main lobe conformal, characterized in that, include: Step S1: Utilize radar to receive echo data and determine the received echo covariance matrix based on the echo data; Step S2: Process the received echo covariance matrix using diagonal loading technology to obtain the loading covariance matrix; Step S3: Determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while ensuring that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value. Step S4: Using the optimal loading amount, determine the adaptive weight after loading; Step S5: Using the loaded adaptive weights, obtain the adaptive reception pattern; The step of determining the optimal loading amount through a pre-configured optimal loading amount calculation model includes: The calculation model is configured based on the criterion of maximizing the output signal-to-interference-plus-noise ratio (SINR) of one target signal while ensuring that the SINR of the other target signal is not less than a certain value. in, For the threshold, The output signal-to-interference-plus-noise ratio of the first target signal. The output signal-to-interference-plus-noise ratio of the second target signal is denoted as , where , ; The covariance matrix of interference plus noise Perform eigenvalue decomposition to obtain the eigenvector matrix corresponding to the interference subspace. The eigenvector matrix corresponding to the noise subspace ; Based on the Lagrange multiplier method, a quadratic function with respect to the loading factor is determined; Using a quadratic function, determine the expression for the optimal loading amount in the loading factor; The value of the Lagrange factor in the expression is determined by using a cyclic iterative method, thereby determining the optimal loading amount.

2. The robust adaptive beamforming method based on main lobe conformity as described in claim 1, characterized in that, The step of utilizing radar echo data and determining the received echo covariance matrix based on the echo data includes: Using radar to receive echo data Obtain the received echo covariance matrix : in, , For two target signals and An interference signal The complex envelopes at time t, and the complex envelopes of the target signal and the interference signal are uncorrelated. Let be the array manifold matrix corresponding to all signals. and The angles of the two target signals, for An angle of the interference signal, For array guide vector, For transpose operation, This is the conjugate transpose operation. The number of antenna elements. The spacing between antenna elements. For the operating wavelength, This represents the Gaussian white noise received by all antenna elements, with a mean of [value missing]. The variance is And it is uncorrelated with all signals. and The power of the two target signals, The noise covariance matrix is ​​the interference plus noise.

3. The robust adaptive beamforming method based on main lobe conformity as described in claim 2, characterized in that, The process of processing the received echo covariance matrix using diagonal loading technology to obtain the loaded covariance matrix includes: Using diagonal loading technology to dock and recover the wave covariance matrix Processing is performed to obtain the loaded covariance matrix. : in, For load size, It is an identity matrix.

4. The robust adaptive beamforming method based on main lobe conformity as described in claim 1, characterized in that, Using the optimal loading amount, the adaptive weights after loading are determined by the following formula: in, To achieve the optimal load, These are the adaptive weights after loading.

5. The robust adaptive beamforming method based on main lobe conformity as described in claim 4, characterized in that, The step of obtaining an adaptive reception pattern using the loaded adaptive weights includes: in, The scanning angle.

6. A robust adaptive beamforming device based on main lobe conformal, characterized in that, include: The acquisition unit is configured to receive echo data using radar and determine the received echo covariance matrix based on the echo data. The diagonal loading unit is configured to process the received echo covariance matrix using diagonal loading technology to obtain the loading covariance matrix. The optimal loading unit is configured to determine the optimal loading amount through a pre-configured optimal loading amount calculation model, wherein the calculation model is configured to maximize the output signal-to-interference-plus-noise ratio of the other target signal while satisfying the condition that the output signal-to-interference-plus-noise ratio of one target signal is not less than a certain value. An adaptive weighting unit is configured to determine the adaptive weights after loading using the optimal loading amount; An adaptive receiving pattern unit is configured to obtain an adaptive receiving pattern using the loaded adaptive weights; The optimal loading unit is further configured as follows: The calculation model is configured based on the criterion of maximizing the output signal-to-interference-plus-noise ratio (SINR) of one target signal while ensuring that the SINR of the other target signal is not less than a certain value. in, For the threshold, The output signal-to-interference-plus-noise ratio of the first target signal. The output signal-to-interference-plus-noise ratio of the second target signal is denoted as , where , ; The covariance matrix of interference plus noise Perform eigenvalue decomposition to obtain the eigenvector matrix corresponding to the interference subspace. The eigenvector matrix corresponding to the noise subspace ; Based on the Lagrange multiplier method, a quadratic function with respect to the loading factor is determined; Using the quadratic function, determine the expression for the optimal loading amount in the loading factor; The value of the Lagrange factor in the expression is determined by using a cyclic iterative method, thereby determining the optimal loading amount.

7. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the robust adaptive beamforming method based on main lobe conformal as described in any one of claims 1 to 5.

8. A computer storage medium, characterized in that, The computer storage medium stores a computer program, which, when executed by a processor, implements the steps of the robust adaptive beamforming method based on main lobe conformal as described in any one of claims 1 to 5.

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