A joint angle measurement method of MUSIC and sum-difference beam based on heterogeneous array

Abstract

This invention presents a method for angle measurement based on a non-circular array using MUSIC and sum-difference beamforming. The method comprises an "L++" shaped array composed of several modular ultra-wideband subarrays. Based on the "+" shaped array, a subarray-level two-dimensional sum-difference beamforming is used to obtain preliminary coarse estimates of azimuth and elevation angles without angular ambiguity. Using the X and Y arms of the "L"-shaped uniform sparse subarray, the MUSIC algorithm is employed to obtain precise estimates of the angles between the target and the X and Y axes where angular ambiguity exists. Utilizing the spatial geometric constraints of the angles between the target and the X and Y axes, a parameter optimization cost function is designed to obtain precise estimates of the angles between the target and the X, Y, and Z axes without angular ambiguity. Based on the spatial geometric mapping of the azimuth and elevation angles to the angles between the X, Y, and Z axes, the final precise estimates of the target's azimuth and elevation angles without angular ambiguity are obtained. This method improves the angle measurement accuracy from 1 / 20th of the subarray beamwidth of the sum-difference beamforming to 1 / 1000th of the subarray beamwidth, achieving space-based two-dimensional angle measurement capabilities with no angular ambiguity, low complexity, and high precision.

Description

Technical Field

[0001] This invention belongs to the field of space-based information acquisition and relates to a method for angle measurement based on MUSIC and sum-difference beam combined with irregular array. Background Technology

[0002] Electronic reconnaissance systems need to operate in ultra-wideband reception (e.g., 2–18 GHz). Considering an orbital altitude of 500 km in low Earth orbit, and with the criterion of being able to detect the vast majority of key communication and radar radiation sources, the size of a single electronic reconnaissance antenna is approximately 0.04 m × 0.04 m (8 × 8 scale). Radar detection systems operating in the 14–18 GHz range require an antenna size of approximately 3.4 m × 0.75 m to achieve meter-level resolution imaging. To achieve aperture sharing between the radar detection system and the electronic reconnaissance system, several 0.04m×0.04m modular ultra-wideband angle scanning subarrays are deployed in the azimuth and range directions of the radar detection system antenna. The phase center spacing of the reconnaissance subarrays is 0.04m, the wavelength of the 18GHz signal is 0.016m, and the ratio of the reconnaissance subarray spacing to the high-frequency 18GHz wavelength is 2.5, forming a uniform sparse array. Conventional 2D-MUSIC is used for angle measurement. Although the angle measurement resolution is high and the angle measurement accuracy is excellent, the large-scale matrix operation and two-dimensional spectral peak search bring a heavy computational burden and produce angle measurement ambiguity. Phased array subarray level sum-difference beam angle measurement, although without angle ambiguity problems, has poor angle measurement accuracy. Therefore, the space-based multi-functional shared aperture payload system lacks a two-dimensional accurate angle measurement method with no angle ambiguity and low computational complexity. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for angle measurement based on MUSIC and sum-difference beams with irregular arrays. This method can avoid the heavy computational burden and angle measurement ambiguity caused by large-scale matrix operations and two-dimensional spectral peak search, and also overcome the low angle measurement accuracy caused by conventional two-dimensional sum-difference beams.

[0004] The technical solution of this invention is: a method for joint angle measurement of MUSIC and sum-difference beams based on irregular arrays, comprising:

[0005] Construct a modular ultrawide bandwidth angle scanning subarray; numbered 1, 2, ..., M, M+1, ..., N, N+1 respectively; M and N are both positive integers;

[0006] Establish a spatial coordinate system OXYZ, with the direction of the incoming wave from the target located within the three-dimensional space formed by the positive semi-axes of X, Y, and Z; define the elevation angle θ as the angle between the direction of the incoming wave and the XOY plane; azimuth angle... Let α be the angle between the projection of the incoming wave direction onto the XOY plane and the X-axis, α be the angle between the incoming wave direction and the Z-axis, β be the angle between the target radiation source and the X-axis, and γ be the angle between the target radiation source and the Y-axis.

[0007] Four modular ultra-wideband wide-angle scanning subarrays were selected to obtain angular-unambiguous images of the target radiation source. A preliminary coarse estimate of θ is obtained; by selecting M modular ultra-wideband bandwidth angle scanning subarrays, a precise estimate of the angle γ between the target radiation source and the Y-axis, where there is angular ambiguity, is calculated. ζ By selecting NM modular ultra-wideband bandwidth angular scanning subarrays, the precise estimate β of the angle between the target radiation source and the X-axis, where angular ambiguity exists, is calculated. ξ ;

[0008] Based on the absence of angular ambiguity in the target radiation source The preliminary rough estimates of θ and the angles between the target radiation source and the X and Y axes are used to calculate the accurate estimates of the angles β and γ between the target radiation source and the X axis without angular ambiguity.

[0009] Based on the accurate estimates of the angle β between the target radiation source and the X-axis and the angle γ between the target radiation source and the Y-axis without angular ambiguity, the accurate estimate of α without angular ambiguity is obtained.

[0010] Calculate the azimuth angle And an accurate estimate of the pitch angle θ' without angular ambiguity.

[0011] Each modular ultra-wide bandwidth angle scanning subarray consists of p×p ultra-wide bandwidth angle scanning planar phased array antenna elements; multiple modular ultra-wide bandwidth angle scanning subarrays form an irregular array, where p is a positive integer.

[0012] The irregular array is constructed as follows: the irregular array is located in the XOY plane, with point O as the origin. The modular ultra-wide bandwidth angle scanning subarray located in the second quadrant is numbered M-1, and sequentially numbered M-2, M-3, ... 2, 1 along the positive Y-axis. The modular ultra-wide bandwidth angle scanning subarray located in the third quadrant is numbered M. The modular ultra-wide bandwidth angle scanning subarray located in the fourth quadrant is numbered M+1, and sequentially numbered M+1, M+2, ..., N-1, N along the positive X-axis. The modular ultra-wide bandwidth angle scanning subarray located in the first quadrant is numbered N+1.

[0013] Four modular ultra-wideband wide-angle scanning subarrays were selected to obtain angular-unambiguous images of the target radiation source. The preliminary coarse estimates of θ include: selecting modular ultra-wideband angular scanning subarrays numbered M, M-1, M+1, and N+1, and using an array-based two-dimensional sum-difference beam angle measurement algorithm to obtain angularly unambiguous values ​​of the target radiation source. The preliminary rough estimates of θ.

[0014] M modular ultra-wideband wide-angle scanning subarrays were selected, and the angle γ between the target radiation source and the Y-axis was calculated. ζThis includes: selecting modular ultra-wideband bandwidth angle scanning subarrays numbered 1, 2, ..., M, and using the one-dimensional uniform sparse linear array MUSIC algorithm to obtain the angle γ between the target radiation source and the Y-axis. ζ The obtained γ ζ For an accurate estimate of the angular ambiguity, ζ is a positive integer greater than or equal to 1.

[0015] By selecting NM modular ultra-wideband bandwidth scanning subarrays, the angle β between the target radiation source and the X-axis is calculated. ξ This includes: selecting modular ultra-wideband bandwidth angle scanning subarrays numbered M, M+1, M+2, ..., N-1, N, and using the one-dimensional uniform sparse linear array MUSIC algorithm to obtain the angle β between the target radiation source and the X-axis. ξ β is obtained ξ For an accurate estimate of the angular ambiguity, ξ is a positive integer greater than or equal to 1.

[0016] The calculated, unambiguous estimates of the angles β and γ between the target radiation source and the X-axis, and between the target radiation source and the Y-axis, are as follows:

[0017]

[0018] The calculation yields an accurate estimate α′ of the included angle α without angular ambiguity:

[0019]

[0020] The accurate azimuth estimate without angular ambiguity was calculated. The precise estimate of the pitch angle θ' is:

[0021]

[0022] θ' = sin -1 (cosα′).

[0023] The condition is that N ≥ 2M-1 and M ≥ 4.

[0024] The advantages of this invention compared to the prior art are:

[0025] This invention addresses the high-precision direction finding and positioning requirements of space-based multi-functional co-aperture payload systems for target radiation sources. It proposes an "L++" type special array composed of modular ultra-wideband angle-scanning subarrays. By jointly employing phased array subarray-level two-dimensional sum-difference beamforming and two one-dimensional MUISC algorithms for angle measurement, it achieves two-dimensional, ambiguity-free, low-complexity, and precise angle measurement capabilities for target radiation sources. The angle measurement accuracy is improved from 1 / 20th of the beamwidth of a conventional sum-difference beamforming subarray to 1 / 1000th of the beamwidth. The proposed method avoids the heavy computational burden and angle measurement ambiguity caused by large-scale matrix operations and two-dimensional spectral peak searches required for obtaining the azimuth and elevation angles of target radiation sources using uniform sparse array 2D-MUSIC algorithms, while also overcoming the low accuracy of conventional two-dimensional sum-difference beamforming. In summary, the method proposed in this invention has high angle measurement accuracy, unambiguous angle measurement results, and low computational load, demonstrating strong innovation and practicality. It effectively enhances the Earth reconnaissance and surveillance capabilities and level of the space-based multi-functional common aperture payload system. Attached Figure Description

[0026] Figure 1 This is a configuration diagram of a combined angle measurement array based on irregular array MUSIC and sum-difference beam;

[0027] Figure 2 This is a flowchart of the combined angle measurement process of MUSIC and sum-difference beams based on irregular arrays;

[0028] Figure 3 This is an array configuration diagram of an embodiment of MUSIC and sum-difference beam joint angle measurement based on irregular array;

[0029] Figure 4 It is a spatial pseudospectral map based on the MUSIC algorithm for estimating γ;

[0030] Figure 5 It is a spatial pseudospectral map based on the MUSIC algorithm for estimating β; Detailed Implementation

[0031] This invention discloses a method for joint angle measurement based on MUSIC (Multiple Signal Classification) and sum-difference beamforming using an irregular array. The steps are as follows:

[0032] like Figure 1 and 2 As shown, each modular ultra-wide bandwidth angle scanning subarray consists of p×p ultra-wide bandwidth angle scanning planar phased array antenna elements, numbered 1, 2, ..., M, M+1, ..., N, N+1 respectively; multiple modular ultra-wide bandwidth angle scanning subarrays form an irregular array, where p, M and N are all positive integers;

[0033] Establish a spatial coordinate system OXYZ, with the direction of the incoming wave from the target located within the three-dimensional space formed by the positive semi-axes of X, Y, and Z; define the elevation angle θ as the angle between the direction of the incoming wave and the XOY plane; azimuth angle... Let α be the angle between the projection of the incoming wave direction onto the XOY plane and the X-axis, β be the angle between the incoming wave direction and the Z-axis, β be the angle between the target radiation source and the X-axis, and γ be the angle between the target radiation source and the Y-axis. The irregular array is located in the XOY plane, with point O as the origin. The modular ultra-wideband wide-angle scanning subarray in the second quadrant is numbered M-1, sequentially numbered M-2, M-3, ..., 2, 1 along the positive Y-axis; the modular ultra-wideband wide-angle scanning subarray in the third quadrant is numbered M; the modular ultra-wideband wide-angle scanning subarray in the fourth quadrant is numbered M+1, sequentially numbered M+1, M+2, ..., N-1, N along the positive X-axis; and the modular ultra-wideband wide-angle scanning subarray in the first quadrant is numbered N+1. N ≥ 2M-1, M ≥ 4.

[0034] Step 1. Based on the modular ultra-wideband angular scanning subarrays numbered M, M-1, M+1, and N+1, a two-dimensional sum-difference beamforming algorithm is used to obtain angularly ambiguity-free results. A preliminary rough estimate of θ.

[0035] The target azimuth angle is determined using an array-based two-dimensional sum-difference beam angle measurement algorithm. A preliminary rough estimate of the pitch angle θ is performed using the following method:

[0036] The phase center coordinates of the four subarrays numbered M-1, N+1, M+1, and M are respectively represented as d M-1 d N+1 d M+1 and d M As shown in the following formula

[0037]

[0038] Assuming that the center of one subarray is located at the origin, the received signal of this subarray can be represented as P0. According to the theory of spatial path difference, the received signals at the phase centers of the four subarrays numbered M-1, N+1, M+1, and M can be represented as follows:

[0039]

[0040] The above formula can be rewritten as

[0041]

[0042] (·) H This represents the conjugate transpose. From the above equation, we can see that the guiding vectors of the phase centers of the four subarrays numbered M-1, N+1, M+1, and M are... It can be represented as:

[0043]

[0044] Assuming the current beam pointing is Then the corresponding weight vector at this time is The outputs of the phase centers of the four subarrays numbered M-1, N+1, M+1, and M are shown in the following formula:

[0045]

[0046] in, V0 = sinθ - sinθ0.

[0047] Based on the configuration of the sum, azimuth difference, and elevation difference beams, it can be seen that the sum beam is the sum of the outputs of subarrays numbered M-1, N+1, M+1, and M, that is:

[0048]

[0049] The azimuth difference beam is numbered M-1. The sum of the received signal outputs of subarray M minus the sum of the received signal outputs of subarray N+1 and M+1 is:

[0050]

[0051] The elevation difference beam is the sum of the received signal outputs of subarrays numbered M-1 and N+1 minus the sum of the received signal outputs of subarrays M and M+1.

[0052]

[0053] From equations (6) and (8), the ratio of the pitch difference beam to the sum beam can be expressed as:

[0054]

[0055] The target's pitch angle θ can then be expressed as:

[0056]

[0057] Where imag(·) represents the imaginary part of the complex signal, It is the slope of the pitch angle error curve.

[0058] From equations (6) and (7), the ratio of the azimuth difference beam to the sum beam can be expressed as:

[0059]

[0060] Then the azimuth of the target It can be represented as:

[0061]

[0062] In the formula, This represents the slope of the azimuth angle curve.

[0063] Step 2. Based on the modular ultra-wideband bandwidth angle scanning subarray numbered 1, 2, ..., M on the Y-axis, the one-dimensional uniform sparse linear array MUSIC algorithm is used to obtain the angle between the target radiation source and the Y-axis, and the obtained γ ζ For an accurate estimate of the angular ambiguity, ζ is a positive integer greater than or equal to 1;

[0064] The angle γ between the direction of incoming wave from the target and the Y-axis is estimated using the one-dimensional uniform sparse linear array MUSIC algorithm, as follows:

[0065] A narrowband far-field plane wave source s(t) is incident from the γ direction onto a one-dimensional uniform sparse linear array consisting of subarrays numbered 1, 2, ..., M, with a subarray spacing of b / 2. Taking the phase center of subarray M as a reference, the received signal of the l-th (l = 1, 2, ..., M) subarray at sampling time t is expressed as:

[0066] x l (t)=w(γ)s(t)+n l (t), l=1,2,…,M (13)

[0067] Where w(γ) is the steering vector, w(γ) = [1 exp(-jΘ) … exp(-j(M-1)Θ)] T ,(·) T This represents the matrix transpose operation. n l (t) represents the Gaussian white noise received by the l-th subarray at time t, with a mean of 0 and a variance of . (Noise power), and is unrelated to the signal part.

[0068] Equation (13) can be rewritten as a more compact vector expression.

[0069] X(t)=w(γ)s(t)+N(t) (14)

[0070] Where X(t)=[x1(t),…,x M (t)] T N(t) = [n1(t), ..., n M (t)] T .

[0071] The autocorrelation of the array output matrix X(t) is obtained, and its eigenvalues ​​are then decomposed.

[0072]

[0073] RS Here is the signal covariance matrix, and the noise covariance matrix is... Σ=diag(κ1,κ2,…κ M ) is the eigenvalue matrix, and diag( denotes the diagonalization operation of the vector. In the case of a single incident signal, U = [e1,e2,…,e M ] = [U S U N ] is the eigenvector matrix, U S =[e1],U N =[e2,e3,…,e M ] refers to the signal and noise subspaces respectively. γ can be found by searching for the maximum value of the spatial pseudospectral function shown in Equation (16). The angle corresponding to the maximum value is the high-precision estimate of γ, but the angle is ambiguous.

[0074]

[0075] Step 3. Based on the modular ultra-wideband bandwidth angle scanning subarray numbered M, M+1, ..., N on the X-axis, the one-dimensional uniform sparse linear array MUSIC algorithm is used to obtain the angle between the target radiation source and the X-axis, and the obtained β ξ For an accurate estimate of the angular ambiguity, ξ is a positive integer greater than or equal to 1;

[0076] The method for estimating the angle β between the direction of the incoming wave and the X-axis using the one-dimensional uniform sparse linear array MUSIC algorithm is the same as the method for estimating γ in step 2. Similarly, a high-precision estimate of β with angular ambiguity can be obtained.

[0077] Step 4. Based on the angle-free blur obtained in Step 1 The initial rough estimate of θ is obtained, and the precise estimate of β and γ without angular ambiguity is obtained by equations (17) and (18);

[0078]

[0079] Step 5. Based on the accurate estimates of β and γ without angular ambiguity obtained in Step 4, the accurate estimate of α without angular ambiguity is obtained by Equation (20).

[0080] (cosα,cosβ,cosγ) are the spatial cosines of the direction of the incoming wave from the target, and they have the following relationship as shown in equation (19):

[0081] cos 2 α+cos 2 β+cos 2 γ=1 (19)

[0082] but,

[0083]

[0084] Step 6. Based on the accurate estimates of α, β, and γ without angular ambiguity obtained in steps 4 and 5, the azimuth angle is obtained by equations (22) and (23). Accurate estimation of pitch angle θ' without angular ambiguity.

[0085] Based on spatial geometric relationships, we know that:

[0086]

[0087] but,

[0088]

[0089] θ' = sin -1 (cosα′) (23)

[0090] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0091] Example:

[0092] An implementation example of a combined angle measurement method based on irregular array MUSIC and sum-difference beamforming is presented. The specific implementation steps are as follows: Figure 3 As shown: A modular ultra-wide bandwidth angle scanning subarray with a size of 0.04m×0.04m and an operating frequency band of 2GHz≤f≤18GHz is formed by 8×8 ultra-wide bandwidth angle scanning planar phased array antenna elements. The modular ultra-wide bandwidth angle scanning subarrays numbered 1, 2, ..., 8, 9, ..., 15, 16 form a special irregular array.

[0093] The irregular array is located in the XOY plane and consists of a modular ultra-wide bandwidth angle scanning subarray with numbers 1, 2, ..., 7 in the second quadrant (uniformly and sparsely arranged along the Y-axis), number 8 in the third quadrant, numbers 9, 10, ..., 15 in the fourth quadrant (uniformly and sparsely arranged along the X-axis), and number 16 in the first quadrant.

[0094] Assuming a far-field narrowband planar radiator operating at 18 GHz, with a signal-to-noise ratio of 10 dB and a snapshot count of 1024, in azimuth angle... When incident on the irregular array at a pitch angle of θ = 5°, the spatial geometric constraints indicate that α = 85°, β = 11.169°, and γ = 80.0384°.

[0095] Step 1. Based on the modular ultra-widebandwidth azimuth scanning subarrays numbered 7, 8, 9, and 16, the target azimuth angle is determined using a two-dimensional sum-difference beamforming algorithm with a "+" shaped array. A preliminary coarse estimate of the elevation angle θ is performed. The sum of the outputs of subarrays 7, 8, 9, and 16 yields the sum beam; the sum of the outputs of subarrays 7 and 8 minus the sum of the outputs of subarrays 9 and 16 yields the azimuth difference beam; the sum of the outputs of subarrays 7 and 16 minus the sum of the outputs of subarrays 8 and 9 yields the elevation difference beam. Assume the beams point towards the azimuth. Pitch θ0 = 0°, the target azimuth angle is measured. The elevation angle θ = 6.2833°. At 18 GHz, the beamwidth of a single modular ultra-wideband angular scanning subarray is approximately 21°, and the angular error in azimuth and elevation measurements is approximately 1 / 20 of the beamwidth, indicating a relatively large angular measurement error.

[0096] Step 2. Based on the modular ultra-wideband angular scanning subarray numbered 1, 2, ..., 8 on the Y-axis, with a phase center spacing of approximately 0.04m between subarrays, which is 2.5 times the wavelength of 18GHz, the one-dimensional uniform sparse linear array MUSIC algorithm is used to obtain the angle between the target wave direction and the Y-axis. The accurate estimates γ″′ with angular ambiguity are -42.984°, -15.374°, 8.717°, 34.625° and 80.019° respectively.

[0097] Step 3. Based on the modular ultra-wideband bandwidth angle scanning subarrays numbered 8, 9, ..., 15 on the X-axis, with a phase center spacing of approximately 0.04m between subarrays, which is 2.5 times the wavelength of 18GHz, the one-dimensional uniform sparse linear array MUSIC algorithm is used to obtain the angle between the target wave direction and the X-axis. The accurate estimates β″′ with angular ambiguity are -39.771°, -12.888°, 11.164° and 37.61° respectively.

[0098] Step 4. Figure 4 , 5 As shown, the azimuth angle obtained in step 1 The pitch angle θ = 6.2833° was initially estimated. Based on the cost function of equations (17) and (18), the accurate estimates of β = 11.164° and γ = 80.019° without angular ambiguity were obtained.

[0099] Step 5. Based on the accurate estimates of angle-free ambiguity β = 11.164° and γ = 80.019° obtained in Step 4, the accurate estimate of angle-free ambiguity α = 85.0493° is obtained by Equation (20).

[0100] Step 6. Based on the precise estimates of angular ambiguity-free α = 85.0493°, β = 11.164° and γ = 80.019° obtained in Steps 4 and 5, the angular ambiguity-free azimuth angle is obtained by equations (22) and (23). The elevation angle θ' = 4.9507° is accurately estimated. Therefore, the azimuth estimation error is 0.0188°, and the elevation estimation error is 0.0493°. The angle estimation error can reach 1 / 1000 to 2 / 1000 of the subarray beamwidth, far exceeding the angular measurement error level of 1 / 20 of the subarray beamwidth for sum and difference beams.

[0101] This embodiment is merely one specific implementation of the present invention. Depending on the system's requirements for the detection performance of target radiation sources and the accuracy of direction finding and positioning, planar phased array antenna elements operating in different frequency bands and of different types can be selected. The number of elements forming a modular ultra-wide bandwidth angle scanning subarray can be increased or decreased, and the number of subarrays forming a special irregular array can be increased or decreased.

[0102] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for joint angle measurement using MUSIC and sum-difference beamforming based on an irregular array, characterized in that... include: Construct a modular ultrawide bandwidth angle scanning subarray; numbered 1, 2, ..., M, M+1, ..., N, N+1 respectively; M and N are both positive integers; Establish a spatial coordinate system OXYZ, with the direction of the incoming wave from the target located within the three-dimensional space formed by the positive semi-axes of X, Y, and Z; define the elevation angle θ as the angle between the direction of the incoming wave and the XOY plane; azimuth angle... Let α be the angle between the projection of the incoming wave direction onto the XOY plane and the X-axis, α be the angle between the incoming wave direction and the Z-axis, β be the angle between the target radiation source and the X-axis, and γ be the angle between the target radiation source and the Y-axis. Four modular ultra-wideband wide-angle scanning subarrays were selected to obtain angular-unambiguous images of the target radiation source. A preliminary coarse estimate of θ is obtained; by selecting M modular ultra-wideband bandwidth angle scanning subarrays, a precise estimate of the angle γ between the target radiation source and the Y-axis, where there is angular ambiguity, is calculated. ζ By selecting NM modular ultra-wideband bandwidth angular scanning subarrays, the precise estimate β of the angle between the target radiation source and the X-axis, where angular ambiguity exists, is calculated. ξ ; Based on the absence of angular ambiguity in the target radiation source The preliminary coarse estimate of θ and the precise estimate of the angle β between the target radiation source and the X and Y axes, which are subject to angular ambiguity. ξ γ ζ The accurate estimates of the angle β between the target radiation source and the X-axis and the angle γ between the target radiation source and the Y-axis without angular ambiguity were obtained by calculation. Based on the accurate estimates of the angle β between the target radiation source and the X-axis and the angle γ between the target radiation source and the Y-axis without angular ambiguity, the accurate estimate of the angle α without angular ambiguity is obtained. Based on the obtained accurate estimates of α, β, and γ without angular ambiguity, the accurate estimate of the azimuth angle without angular ambiguity is calculated. And the precise estimate of the pitch angle θ'; Each modular ultra-wide bandwidth angle scanning subarray consists of p×p ultra-wide bandwidth angle scanning planar phased array antenna elements; multiple modular ultra-wide bandwidth angle scanning subarrays form an irregular array, where p is a positive integer; The irregular array is constructed as follows: the irregular array is located in the XOY plane, with point O as the origin. The modular ultra-wide bandwidth angle scanning subarray located in the second quadrant is numbered M-1, and sequentially numbered M-2, M-3, ... 2, 1 along the positive Y-axis. The modular ultra-wide bandwidth angle scanning subarray located in the third quadrant is numbered M. The modular ultra-wide bandwidth angle scanning subarray located in the fourth quadrant is numbered M+1, and sequentially numbered M+1, M+2, ..., N-1, N along the positive X-axis. The modular ultra-wide bandwidth angle scanning subarray located in the first quadrant is numbered N+1. Four modular ultra-wideband wide-angle scanning subarrays were selected to obtain angular-unambiguous images of the target radiation source. The preliminary coarse estimates of θ include: selecting modular ultra-wideband angular scanning subarrays numbered M, M-1, M+1, and N+1, and using an array-based two-dimensional sum-difference beamforming algorithm to obtain angularly unambiguous values ​​of the target radiation source. Preliminary rough estimates of θ; By selecting M modular ultra-wideband wide-angle scanning subarrays, the accurate estimate of the angle γ between the target radiation source and the Y-axis, where there is angular ambiguity, is calculated. ζ This includes: selecting modular ultra-wideband bandwidth angular scanning subarrays numbered 1, 2, ..., M, and using the one-dimensional uniform sparse linear array MUSIC algorithm to obtain an accurate estimate of the angle γ between the target radiation source and the Y-axis where there is angular ambiguity. ζ ζ is a positive integer greater than or equal to 1; By selecting NM modular ultrawide bandwidth wide-angle scanning subarrays, the accurate estimate β of the angle between the target radiation source and the X-axis, where there is angular ambiguity, is calculated. ξ This includes: selecting modular ultra-wideband bandwidth angle scanning subarrays numbered M, M+1, M+2, ..., N-1, N, and using the one-dimensional uniform sparse linear array MUSIC algorithm to obtain an accurate estimate β of the angle between the target radiation source and the X-axis where there is angular ambiguity. ξ ξ is a positive integer greater than or equal to 1.

2. The method for joint angle measurement of MUSIC and sum-difference beams based on an irregular array according to claim 1, characterized in that: The calculated, unambiguous estimates of the angles β and γ between the target radiation source and the X-axis, and between the target radiation source and the Y-axis, are as follows:

3. The method for joint angle measurement of MUSIC and sum-difference beams based on an irregular array according to claim 2, characterized in that: The precise estimate α′ of the included angle α without angular ambiguity is:

4. The method for joint angle measurement of MUSIC and sum-difference beams based on an irregular array according to claim 3, characterized in that: The accurate azimuth estimate without angular ambiguity was calculated. The precise estimate of the pitch angle θ' is: θ'=sin -1 (cos α′).

5. A method for joint angle measurement of MUSIC and sum-difference beams based on an irregular array according to any one of claims 1-4, characterized in that: The condition is that N ≥ 2M-1 and M ≥ 4.

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