Angle measurement method suitable for radar with any subarray architecture

Abstract

The invention provides an angle measurement method suitable for any sub-array architecture radar, a storage medium and electronic equipment, and relates to the technical field of radars. According to the method, firstly, a plurality of sub-arrays are divided based on task requirements, and sub-array-level beam forming is executed to construct a sub-array echo signal vector model; secondly, estimating a subarray phase center by adopting a calibration signal inversion method; constructing a subarray phase gradient vector again; and finally, estimating a phase gradient centroid by adopting a weighted phase gradient method so as to obtain a target angle measurement result. According to the method, the phase gradient is adopted as the basis of angle measurement, the phase difference between the sub-arrays is normalized through the adjacent sub-array intervals, the phase difference between the different sub-array intervals is only related to the target angle and is not related to the sub-array length, then the method can be suitable for a radar antenna array divided by any sub-array, and the design limitation of an antenna is reduced. In addition, the synthesis of the subarrays further reduces the operation scale, and improves the real-time calculation performance of the system.

Description

Technical Field

[0001] The present invention relates to the field of radar technology, and in particular to an angle measurement method, storage medium, and electronic equipment applicable to radars with arbitrary subarray architectures. Background Art

[0002] Digital beamforming (DBF) technology uses digital techniques to implement beamforming. It preserves all information about antenna array element signals and can process array signals using advanced digital signal processing techniques, resulting in excellent beamforming performance. In modern radar systems, to enhance detection power and improve angle measurement accuracy, radar antennas typically contain hundreds or even tens of thousands of elements, making it difficult to implement digital beamforming at the element level. Large arrays are typically divided into subarrays, with analog phase shifters used within each subarray for beamforming. Digital beamforming is then employed between subarrays. This significantly reduces the number of channels required for reception and saves hardware costs.

[0003] However, due to limitations in the structure of T / R components and power splitter networks, it's often impossible to arbitrarily divide antenna arrays into subarrays, especially for large two-dimensional arrays. Therefore, relying solely on optimizing subarray division to improve beamforming performance is undesirable. Many phased array radars use monopulse angle measurement technology, which requires simultaneous sum and difference beamforming. Subarray simulation synthesis uses only one power splitter network, making it impossible to simultaneously form sum and difference beams for angle measurement using the amplitude-weighted approach used in full-array element processing. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the shortcomings of the existing technology, the present invention provides an angle measurement method, storage medium and electronic equipment suitable for radars with arbitrary subarray architectures, which solves the technical problem of antenna design limiting subarray division.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] An angle measurement method applicable to a radar with an arbitrary subarray architecture, comprising:

[0009] Divide the array into several subarrays based on mission requirements and perform subarray-level beamforming to construct subarray echo signal vector models.

[0010] Based on the divided sub-array structure, the calibration signal inversion method is used to estimate the sub-array phase center;

[0011] Constructing a phase vector of a subarray echo signal, and constructing a subarray phase gradient vector in combination with the subarray phase center;

[0012] The distance between adjacent sub-array phase centers is calculated to construct the sub-array gain normalization vector, and the weighted phase gradient method is used to estimate the phase gradient centroid to obtain the target angle measurement result.

[0013] Preferably, based on the task requirements, N linearly uniformly distributed array elements are divided into M sub-arrays, N m is the number of array elements contained in the mth sub-matrix, The performing subarray-level beamforming to construct a subarray echo signal vector model includes:

[0014] The radar echo signal of N linearly uniformly distributed array elements is modeled as Where d is the array element spacing, λ is the radar operating wavelength, θ t is the incident angle of the target, the subscript t indicates that the angle corresponds to the target, e is a natural constant, sin is the sine function, j is the imaginary unit, and the superscript T indicates transposition;

[0015] Synthesize the mth subarray echo signal The subscripts m and k correspond to the kth element of the mth subarray, and the element sequence number in the entire array is w m,k is the amplitude weighted value of the array element, s m,k is the echo signal of the array element, a m,k is the sub-array synthetic steering vector, which is I m,k elements, θ b is the synthesized beam pointing center angle, and the subscript b indicates that the angle corresponds to the beam center angle;

[0016] The synthetic signal of each sub-array is constructed into a signal vector form to construct the sub-array echo signal vector model X=[x1,...,x m ,...,x M ] T .

[0017] Preferably, the sub-array phase center estimation based on the divided sub-array structure using a calibration signal inversion method includes:

[0018] Definition from Angle calibration signal The subscript c indicates that the angle is the angle of the calibration signal;

[0019] Perform subarray synthesis based on the divided subarray structure to obtain the subarray synthesis results of the calibration signal where e m,k For the I m,k The calibration signal received by each array element is the Ith value of the calibration signal E. m,k elements;

[0020] Estimate the phase center of each sub-array where φ c =angle(y' m ) represents the calibration signal y' received by the mth sub-array m The phase value of the signal, angle represents the phase of the signal;

[0021] Repeat the above operation for P calibration signals at different angles to obtain in is the phase center position vector of the mth subarray estimated from P calibration signals at different angles.

[0022] Preferably, constructing the phase vector of the subarray echo signal and constructing the subarray phase gradient vector in combination with the subarray phase center includes:

[0023] Construct the phase vector of the sub-array echo signal Φ=[angle(x1),angle(x2),…,angle(x M )] T ;

[0024] Constructing phase gradient vector in is the phase gradient of the mth subarray.

[0025] Preferably, the sub-array gain normalization vector is expressed as ,in is the normalized gain coefficient of the mth sub-matrix.

[0026] Preferably, the method of estimating the phase gradient centroid using a weighted phase gradient method to obtain a target angle measurement result includes:

[0027] Estimated phase gradient centroid Among them, ||·||1 is a norm;

[0028] Get target angle measurement results Where arcsin is the inverse sine function.

[0029] An angle measurement system applicable to a radar with an arbitrary subarray architecture, comprising:

[0030] A subarray echo signal vector model construction module is used to divide a number of subarrays based on task requirements and perform subarray-level beamforming to construct a subarray echo signal vector model;

[0031] The subarray phase center estimation module is used to estimate the subarray phase center based on the divided subarray structure using the calibration signal inversion method;

[0032] A subarray phase gradient vector construction module is used to construct a phase vector of a subarray echo signal and to construct a subarray phase gradient vector in combination with the subarray phase center;

[0033] The target angle measurement result acquisition module is used to calculate the distance between the phase centers of adjacent sub-arrays to construct the sub-array gain normalization vector, and use the weighted phase gradient method to estimate the phase gradient centroid to obtain the target angle measurement result.

[0034] A storage medium stores a computer program for angle measurement applicable to a radar with an arbitrary sub-array architecture, wherein the computer program enables a computer to execute the above-mentioned angle measurement method applicable to a radar with an arbitrary sub-array architecture.

[0035] An electronic device, comprising:

[0036] One or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for executing the angle measurement method applicable to a radar with an arbitrary sub-array architecture as described above.

[0037] (3) Beneficial effects

[0038] The present invention provides an angle measurement method, storage medium, and electronic device applicable to radars with arbitrary subarray architectures. Compared with existing technologies, it has the following advantages:

[0039] In this invention, several subarrays are first divided based on mission requirements, and subarray-level beamforming is performed to construct a subarray echo signal vector model. A calibration signal inversion method is then used to estimate the subarray phase center. The subarray phase gradient vector is then constructed. Finally, a weighted phase gradient method is used to estimate the phase gradient centroid to obtain the target angle measurement result. This method uses the phase gradient as the basis for angle measurement. It normalizes the phase difference between subarrays by the spacing between adjacent subarrays, ensuring that the phase difference between subarrays with different spacing is only related to the target angle and is independent of the subarray length. This makes it applicable to radar antenna arrays with arbitrary subarray divisions, reducing antenna design constraints. Furthermore, subarray synthesis further reduces the scale of operations and improves the system's real-time computing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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.

[0041] Figure 1A schematic flow chart of an angle measurement method applicable to a radar with an arbitrary subarray architecture provided by an embodiment of the present invention;

[0042] Figure 2 Full array and sub-array directional patterns provided by embodiments of the present invention;

[0043] Figure 3 A schematic diagram of a sub-array phase center provided in an embodiment of the present invention;

[0044] Figure 4 A comparison chart of the angle measurement error results for targets at different angles provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0046] The embodiments of the present application solve the technical problem of antenna design limiting sub-array division by providing an angle measurement method, storage medium, and electronic device applicable to radars with arbitrary sub-array architectures.

[0047] The technical solutions in the embodiments of this application are to solve the above technical problems, and the core technical improvements are as follows:

[0048] The embodiments of the present invention use phase gradient as the basis for angle measurement. This method normalizes the phase difference between subarrays by their spacing, ensuring that the phase difference at different subarray spacings is related only to the target angle and not to the subarray length. Therefore, angle measurement using phase gradient is applicable to radar antenna arrays with any subarray division, reducing antenna design constraints. Furthermore, the present invention further reduces computational complexity through subarray synthesis, improving the system's real-time computing performance.

[0049] The phase value is a parameter corresponding to the wavelength. The phase gradient method uses the subarray spacing to normalize the phase, which requires high accuracy for the subarray spacing. To achieve high-precision estimation of the subarray spacing, this embodiment of the present invention uses a calibration signal inversion method. This method uses a series of calibration signals at different angles to invert the subarray spacing and then estimates the phase center of the subarray by combining the inversion results of multiple calibration signals.

[0050] Furthermore, considering that signal quality varies with subarray lengths, directly calculating the mean value is susceptible to poor signal quality estimates. Therefore, this embodiment of the present invention also normalizes the subarray gains and weights the subarray phase gradients before calculating the centroid to ensure robust angle measurement.

[0051] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0052] Example 1:

[0053] like Figure 1 As shown, an embodiment of the present invention provides an angle measurement method applicable to a radar with an arbitrary subarray architecture, comprising:

[0054] S1. Divide the array into several subarrays based on the mission requirements and perform subarray-level beamforming to construct a subarray echo signal vector model.

[0055] S2. Based on the divided sub-array structure, the sub-array phase center is estimated using the calibration signal inversion method;

[0056] S3, constructing a phase vector of the sub-array echo signal, and constructing a sub-array phase gradient vector in combination with the sub-array phase center;

[0057] S4. Calculate the distance between adjacent sub-array phase centers to construct the sub-array gain normalization vector, and use the weighted phase gradient method to estimate the phase gradient centroid to obtain the target angle measurement result.

[0058] The embodiments of the present invention utilize synthetic subarrays to reduce system complexity, adapt to arbitrary subarray partitioning architectures through subarray phase center estimation, and implement angle measurement through the phase gradient method, thereby reducing the need for uniform division of antenna elements during radar system subarray synthesis.

[0059] Next, we will introduce the various steps of this method in detail with specific examples:

[0060] In step S1, several subarrays are divided based on the task requirements, and subarray-level beamforming is performed to construct a subarray echo signal vector model. The relevant steps are as follows:

[0061] S11. Divide N linearly uniformly distributed array elements into M sub-arrays based on task requirements. m is the number of array elements contained in the mth sub-matrix,

[0062] For example, in the embodiment of the present invention, the antenna is specifically set to have N=64 antenna elements, the element spacing is d=0.05m, and the operating wavelength is λ=0.1m. The antenna elements are divided into M=8 sub-arrays, and the number of elements in each sub-array is N. mThey are 4, 8, 8, 12, 8, 12, 4, and 8 respectively.

[0063] S12. Model the radar echo signal of N linearly uniformly distributed array elements as Where d is the array element spacing, λ is the radar operating wavelength, θ t is the incident angle of the target, the subscript t indicates that the angle corresponds to the target, e is a natural constant, sin is the sine function, j is the imaginary unit, and the superscript T indicates transposition.

[0064] S13, synthesize the mth sub-array echo signal The subscripts m and k correspond to the kth element of the mth subarray, and the element sequence number in the entire array is w m,k is the amplitude weighted value of the array element, s m,k is the echo signal of the array element, a m,k is the sub-array synthetic steering vector, which is I m,k elements, θ b is the synthesized beam pointing center angle, and the subscript b indicates that the angle corresponds to the beam center angle.

[0065] Continuing with the above example, the embodiment of the present invention specifically adopts a Taylor window amplitude weighting value with a sidelobe level of -40dB. The synthesized beam pointing center angle θ b =45°. Figure 2 As shown, Figure 2 The beam patterns of the full array and the eight sub-arrays. Different sub-array widths correspond to different mainlobe widths.

[0066] S14, constructing the synthetic signal of each sub-array into a signal vector form to construct a sub-array echo signal vector model X = [x1, ..., x m ,...,x M ] T .

[0067] In step S2, based on the divided sub-array structure, the calibration signal inversion method is used to estimate the sub-array phase center. The relevant steps are as follows:

[0068] S21、Definition from Angle calibration signal The subscript c indicates that the angle is the angle of the calibration signal.

[0069] S22: Perform subarray synthesis based on the subarray structure divided in S1 to obtain the subarray synthesis result of the calibration signal. where e m,k For the I m,k The calibration signal received by each array element is the Ith value of the calibration signal E. m,k elements.

[0070] S23. Estimate the phase center of each sub-array where φ c =angle(y' m ) represents the calibration signal y' received by the mth sub-array m The phase value of the signal, angle represents the phase of the signal.

[0071] S24, repeat the above steps S21 to S23 for P calibration signals at different angles to obtain in is the phase center position vector of the mth subarray estimated from P calibration signals at different angles.

[0072] Continuing with the above example, in the embodiment of the present invention, P is specifically set to 7, and the calibration signal angles are 44.1000, 44.4000, 44.7000, 45.0000, 45.3000, 45.6000, and 45.900, respectively, in degrees. The array element signal is generated by the aforementioned calibration signal, and then the subarray echo signal is generated by synthesizing the beam synthesis vector with a beam center of 45 degrees and the weighted vector. The phase of each subarray at each angle is obtained, and the phase center position of the subarray is inverted by the subarray phase and the target angle: 0.1303, 0.4573, 0.8438, 1.3396, 1.8207, 2.2890, 2.7180, and 2.9937, in meters. Figure 3 As shown, Figure 3 The relative position distribution of the phase center and array elements obtained for this example.

[0073] In step S3, the phase vector of the sub-array echo signal is constructed, and the sub-array phase gradient vector is constructed in combination with the sub-array phase center. The relevant steps are as follows:

[0074] S31, construct the phase vector Φ of the sub-array echo signal = [angle(x1),angle(x2),…,angle(x M )] T .

[0075] S32, construct phase gradient vector in is the phase gradient of the mth subarray.

[0076] In step S4, the distance between the phase centers of adjacent sub-arrays is calculated to construct the sub-array gain normalization vector, and the phase gradient centroid is estimated using the weighted phase gradient method to obtain the target angle measurement result. The relevant steps are as follows:

[0077] S41. Construct sub-array gain normalization weight vector ,in is the normalized gain coefficient of the mth sub-matrix.

[0078] Continuing with the above example, here f m They are 6.3033, 8.7979, 14.4901, 13.6360, 12.9237, 10.8410 and 4.4792 respectively.

[0079] S42. Estimation of phase gradient centroid Where ||·||1 is a norm.

[0080] S43. Obtain target angle measurement results Where arcsin is the inverse sine function.

[0081] Continuing with the above example, after generating target array element echoes at different angles from 43.5 degrees to 46.5 degrees, the echoes at each angle are synthesized using a sub-array with a beam center of 45 degrees. After obtaining the phase value of each sub-array, the phase gradient is constructed in conjunction with the phase center, and the angle measurement result is obtained using the sub-array gain weighting. Figure 4 As shown, Figure 4 The error distribution of the angle measurement results for this example is shown in Figure 2. It can be seen that when directly using the subarray phase center for angle measurement, the angle measurement deviation for targets at different angles exceeds ±0.1°. However, when using the subarray phase center obtained by this method for angle measurement, the angle measurement deviation for targets at different angles is within ±0.01°. This indicates that the angle measurement performance is good for targets at different angles.

[0082] So far, the embodiment of the present invention has completed the entire process of the angle measurement method applicable to a radar with any subarray architecture.

[0083] Example 2:

[0084] An embodiment of the present invention provides an angle measurement system applicable to a radar with an arbitrary subarray architecture, comprising:

[0085] A subarray echo signal vector model construction module is used to divide a number of subarrays based on task requirements and perform subarray-level beamforming to construct a subarray echo signal vector model;

[0086] The subarray phase center estimation module is used to estimate the subarray phase center based on the divided subarray structure and adopt the calibration signal inversion method;

[0087] A subarray phase gradient vector construction module is used to construct a phase vector of a subarray echo signal and to construct a subarray phase gradient vector in combination with the subarray phase center;

[0088] The target angle measurement result acquisition module is used to calculate the distance between the phase centers of adjacent sub-arrays to construct the sub-array gain normalization vector, and use the weighted phase gradient method to estimate the phase gradient centroid to obtain the target angle measurement result.

[0089] Example 3:

[0090] An embodiment of the present invention provides a storage medium storing a computer program for angle measurement applicable to a radar with an arbitrary subarray architecture, wherein the computer program enables a computer to execute the angle measurement method applicable to a radar with an arbitrary subarray architecture as described in Example 1.

[0091] Example 4:

[0092] An embodiment of the present invention provides an electronic device, including:

[0093] One or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, the programs including instructions for executing the angle measurement method applicable to an arbitrary subarray architecture radar as described in Example 1.

[0094] It is understandable that the angle measurement system, storage medium, and electronic device applicable to a radar with an arbitrary subarray architecture provided in the embodiments of the present invention correspond to the angle measurement method applicable to a radar with an arbitrary subarray architecture provided in the embodiments of the present invention. For explanations, examples, and beneficial effects of the relevant contents, reference can be made to the corresponding parts in the angle measurement method and will not be repeated here.

[0095] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for measuring angles of a radar with an arbitrary subarray architecture, characterized in that: include: Divide the array into several subarrays based on mission requirements and perform subarray-level beamforming to construct subarray echo signal vector models. Based on the divided sub-array structure, the calibration signal inversion method is used to estimate the sub-array phase center; Constructing a phase vector of a subarray echo signal, and constructing a subarray phase gradient vector in combination with the subarray phase center; The distance between adjacent sub-array phase centers is calculated to construct the sub-array gain normalization vector, and the weighted phase gradient method is used to estimate the phase gradient centroid to obtain the target angle measurement result.

2. The angle measurement method applicable to an arbitrary subarray radar according to claim 1, characterized in that: Based on the task requirements, N linearly uniformly distributed array elements are divided into M sub-arrays, N m is the number of array elements contained in the mth sub-matrix, The performing subarray-level beamforming to construct a subarray echo signal vector model includes: The radar echo signal of N linearly uniformly distributed array elements is modeled as Where d is the array element spacing, λ is the radar operating wavelength, θ t is the incident angle of the target, the subscript t indicates that the angle corresponds to the target, e is a natural constant, sin is the sine function, j is the imaginary unit, and the superscript T indicates transposition; Synthesize the mth subarray echo signal m=1,2,…,M, where the subscripts m and k correspond to the kth element of the mth subarray, and the element sequence number in the entire array is w m,k is the amplitude weighted value of the array element, s m,k is the echo signal of the array element, a m,k is the sub-array synthetic steering vector, which is I m,k elements, θ b is the synthesized beam pointing center angle, and the subscript b indicates that the angle corresponds to the beam center angle; The synthetic signal of each sub-array is constructed into a signal vector form to construct the sub-array echo signal vector model X=[x1,...,x m ,...,x M ] T .

3. The angle measurement method applicable to an arbitrary subarray radar according to claim 2, characterized in that: The subarray structure based on the division adopts the calibration signal inversion method to estimate the subarray phase center, including: Definition from Angle calibration signal The subscript c indicates that the angle is the angle of the calibration signal; Perform subarray synthesis based on the divided subarray structure to obtain the subarray synthesis results of the calibration signal where e m,k For the I m,k The calibration signal received by each array element is the Ith value of the calibration signal E. m,k elements; Estimate the phase center of each sub-array where φ c =angle(y' m ) represents the calibration signal y' received by the mth sub-array m The phase value of the signal, angle represents the phase of the signal; Repeat the above operation for P calibration signals at different angles to obtain in is the phase center position vector of the mth subarray estimated from P calibration signals at different angles.

4. The angle measurement method applicable to an arbitrary subarray radar according to claim 3, characterized in that: The step of constructing a phase vector of a subarray echo signal and constructing a subarray phase gradient vector in combination with the subarray phase center includes: Construct the phase vector of the sub-array echo signal Φ=[angle(x1),angle(x2),…,angle(x M )] T ; Constructing phase gradient vector in is the phase gradient of the mth subarray.

5. The angle measurement method applicable to an arbitrary subarray radar according to claim 4, characterized in that: The subarray gain normalization vector is expressed as ,in is the normalized gain coefficient of the mth sub-matrix.

6. The angle measurement method applicable to an arbitrary subarray radar according to claim 5, characterized in that: The method of estimating the phase gradient centroid using the weighted phase gradient method to obtain the target angle measurement result includes: Estimated phase gradient centroid Among them, ||·||1 is a norm; Get target angle measurement results Where arcsin is the inverse sine function.

7. An angle measurement system suitable for radar with arbitrary subarray architecture, characterized in that: include: A subarray echo signal vector model construction module is used to divide a number of subarrays based on task requirements and perform subarray-level beamforming to construct a subarray echo signal vector model; The subarray phase center estimation module is used to estimate the subarray phase center based on the divided subarray structure and adopt the calibration signal inversion method; A subarray phase gradient vector construction module is used to construct a phase vector of a subarray echo signal and to construct a subarray phase gradient vector in combination with the subarray phase center; The target angle measurement result acquisition module is used to calculate the distance between the phase centers of adjacent sub-arrays to construct the sub-array gain normalization vector, and use the weighted phase gradient method to estimate the phase gradient centroid to obtain the target angle measurement result.

8. A storage medium, characterized in that: The computer program for angle measurement applicable to a radar with an arbitrary sub-array architecture is stored therein, wherein the computer program enables a computer to execute the angle measurement method applicable to a radar with an arbitrary sub-array architecture as claimed in any one of claims 1 to 6.

9. An electronic device, characterized in that: include: one or more processors; Memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for executing the angle measurement method applicable to a radar with an arbitrary sub-array architecture according to any one of claims 1 to 6.

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