Beamforming Method and System Based on Preformed Beam Angle Near-Field Compensation and FFT Acceleration

Abstract

This invention relates to a beamforming method and system based on pre-formed beam angle near-field compensation and FFT acceleration. The method includes: S1, generating a set of pre-formed beam angles and determining key beam angles according to the multi-beam detection device and the type of detection mission; S2, acquiring channel data based on the key beam angles, performing near-field compensation focusing calculations for each key beam angle on the channel data to obtain several key beam angle focusing signals; S3, performing Fast Fourier Transform (FFT) on the several key beam angle focusing signals, and then stitching the FFT-transformed key beam angle focusing signals together to obtain a beam domain signal; S4, outputting the beam domain signal for subsequent imaging processing. This invention, by performing focusing calculations based on key beam angles and combining them with FFT-accelerated beam domain data generation, significantly reduces computational complexity while ensuring imaging quality, and is suitable for low-power real-time systems such as sonar, radar, and medical imaging.

Description

Technical Field

[0001] This invention relates to the field of beamforming technology, and in particular to a beamforming method and system based on preformed beam angle near-field compensation and FFT acceleration. Background Technology

[0002] In sonar, radar, and medical ultrasound imaging systems, beamforming is a core technology for achieving spatial signal focusing and direction estimation, playing a crucial role. However, traditional beamforming methods often face numerous challenges, which to some extent limit their performance and efficiency in practical applications.

[0003] While traditional full-angle scanning methods can acquire spatial information comprehensively, this approach requires scanning each angle individually, resulting in a massive computational burden. As the number of scanning angles increases, the computational complexity grows exponentially. This consumes significant computing resources when processing large amounts of data, slowing down the system and making it difficult to meet the demands of real-time applications.

[0004] While adaptive beamforming methods can automatically adjust beam parameters according to the signal environment to some extent and improve image quality, they also suffer from high computational complexity. This is especially true in near-field imaging scenarios, where the situation becomes even more complex. In the near field, the wave propagation path is no longer a simple plane wave assumption, but rather requires consideration of the propagation characteristics of spherical waves. This makes compensation for propagation path delay extremely critical and complex. Accurately compensating for this delay necessitates meticulous processing and analysis of the signal received by each array element, involving numerous mathematical operations and complex algorithms, further increasing computational resource consumption.

[0005] In addition, existing technologies mostly rely on large-scale matrix operations or iterative optimization algorithms to achieve beamforming. Large-scale matrix operations and large-scale matrix operations have high requirements for system storage resources and computing power, which makes it difficult to meet the real-time and low-power requirements of embedded systems.

[0006] Therefore, there is an urgent need for a beamforming method that can achieve efficient focusing and reduce computational complexity under near-field conditions. Summary of the Invention

[0007] To address the technical problems existing in the prior art, the present invention aims to provide a beamforming method based on preformed beam angle near-field compensation and FFT acceleration, which significantly reduces computational complexity while ensuring imaging quality.

[0008] To achieve the above-mentioned objectives, this invention provides a beamforming method based on preformed beam angle near-field compensation and FFT acceleration, comprising the following steps:

[0009] Step S1: Based on the multi-beam detection device and the type of detection mission, generate a pre-formed beam angle set, and optimize the pre-formed beam angle set to determine the key beam angles;

[0010] Step S2: Obtain channel data based on the key beam angle, and perform near-field compensation focusing calculation on the channel data for each key beam angle to obtain several key beam angle focusing signals;

[0011] Step S3: Perform Fast Fourier Transform on several key beam angle focusing signals, and then reassemble the key beam angle focusing signals after Fast Fourier Transform to obtain beam domain signals.

[0012] Step S4: Output the beam domain signal for subsequent imaging processing.

[0013] According to one technical solution of the present invention, step S1 specifically includes:

[0014] Step S11: Determine the pre-formed beam angle set according to the detection mission requirements and the equipment parameters of the multi-beam detection device; the detection mission requirements include the type of detection mission and the detection mission opening angle range;

[0015] Step S12: Optimize the pre-formed beam angle set according to the type of detection mission to determine the key beam angle.

[0016] According to one technical solution of the present invention, step S11 specifically includes:

[0017] Step S111: Calculate the pre-formed beam angular resolution based on the equipment parameters of the multi-beam detection device, expressed as:

[0018] Let the aperture of the sensor array in the multi-beam detector be D, and the operating wavelength be λ. Then the beam angular resolution Δθ of the multi-beam detector satisfies:

[0019] Δθ=arcsin(λ / D)

[0020] Step S112: Based on the detection mission's opening angle range and the calculated beam angle resolution Δθ, determine the number of pre-formed beam angles and generate a set of pre-formed beam angles; for several pre-formed beam angles in the set of pre-formed beam angles, the beam angle interval between two adjacent pre-formed beam angles is an integer multiple of the beam angle resolution Δθ, and the coverage range of several pre-formed beam angles is not less than the detection mission's opening angle range.

[0021] According to one technical solution of the present invention, step S12 specifically includes:

[0022] Based on the high-efficiency mode required by the detection mission, the preformed beam angle set is divided equally using a uniform angular spacing method, and a preformed beam angle is selected from each of the equally divided subsets as the key beam angle.

[0023] Based on the high-resolution mode requirement of the detection mission, a high-resolution mode optimization strategy was adopted to select the key beam angle, specifically including:

[0024] Based on the key area requirements of the detection mission, the pre-formed beam angle set is divided into a key area angle set and a non-key area angle set;

[0025] Within the set of key area angles, several first pre-formed beam angles are selected using a uniform angle spacing method according to the first key beam angle interval; within the non-key area, several second pre-formed beam angles are selected using a uniform angle spacing method according to the second key beam angle interval.

[0026] The first critical beam angle spacing is smaller than the second critical beam angle spacing, and both the first pre-formed beam angle and the second pre-formed beam angle are integer multiples of the beam angle resolution.

[0027] According to one technical solution of the present invention, step S2 specifically includes:

[0028] Step S21: Establish a near-field propagation model and calculate the time delay difference between each element in the sensor array of the multi-beam detection device and the aggregation point;

[0029] Step S22: Perform time delay compensation on the channel data;

[0030] Step S23: Perform a weighted summation on the channel data after time delay compensation to generate the focusing signal corresponding to the pre-formed beam angle.

[0031] According to one technical solution of the present invention, step S21 specifically includes:

[0032] Let N be the number of array elements in the sensor array and M be the number of key beam angles. θ The coordinates of the focal point are The coordinates of the nth array element are The key beam angle The time delay difference is

[0033]

[0034] Where m represents the index of the critical beam angle, To measure the propagation speed of sonar detection signals, The reference array element position.

[0035] According to a technical solution of the present invention, in step S22, the channel data of the nth array element is rotated using a phase rotation method. Phase compensation is represented as:

[0036]

[0037] in, This refers to the channel data of the nth array element after phase compensation. Represents the imaginary unit. Represents different sampling points of the signal. For carrier frequency.

[0038] According to a technical solution of the present invention, in step S23, the key beam angle The corresponding key beam angle focusing signal is represented as follows:

[0039]

[0040] in, The element weighting coefficient for the nth element is used to suppress sidelobes or optimize beam shape.

[0041] According to one technical solution of the present invention, step S3 specifically includes:

[0042] Step S31: Perform an M-point FFT operation on the key beam angle focusing signal to obtain beam domain data. , is represented as:

[0043]

[0044] in, 0, 1, ... M-1 correspond to different beam directions within the critical beam angle. ;

[0045] The number of points M in the FFT operation and the number of key beam angles M θ Satisfy: M*M θ ≥ The preset number of beams for multi-beam detection devices;

[0046] Step S32: Perform zero-filling and interpolation processing on the beam domain data to improve the resolution of the beam domain data.

[0047] According to one aspect of the present invention, a beamforming system based on preformed beam angle near-field compensation and FFT acceleration is provided for implementing the above-mentioned beamforming method based on preformed beam angle near-field compensation and FFT acceleration, comprising:

[0048] The pre-formed beam angle selection module is used to generate a set of pre-formed beam angles based on the multi-beam detection device and the type of detection mission, and to optimize the set of pre-formed beam angles to determine the key beam angles.

[0049] The focusing calculation module is used to perform near-field compensation focusing calculation based on the key beam angle to obtain several key beam angle focusing signals;

[0050] The FFT calculation module is used to perform fast Fourier transform calculation on the key beam angle focusing signal to obtain the beam domain signal.

[0051] The power supply module is electrically connected to the pre-formed beam angle selection module, the focusing calculation module, and the FFT calculation module, and is used to supply power to the pre-formed beam angle selection module and the focusing calculation module;

[0052] A dynamic clock gating module, connected to the power supply module, sends an FFT shutdown control signal to the power supply module according to the inactive calculation cycle.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] This invention proposes a beamforming method based on preformed beam angle near-field compensation and FFT acceleration. By optimizing the preformed beam angle set based on a key beam angle selection strategy, several key beam angles are selected within the channel data for focusing calculation. The beam domain data is generated through Fast Fourier Transform. This method reduces computational complexity by 40%-60% in near-field imaging scenarios while maintaining spatial resolution and imaging quality. It is suitable for low-power real-time systems such as sonar, radar, and medical imaging. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0056] Figure 1 A flowchart illustrating the beamforming method based on preformed beam angle near-field compensation and FFT acceleration provided in an embodiment of the present invention is shown in the figure.

[0057] Figure 2 The schematic diagram illustrates the structure of a beamforming system based on preformed beam angle near-field compensation and FFT acceleration provided in an embodiment of the present invention. Detailed Implementation

[0058] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0059] The descriptions of the embodiments herein, including any references to directions and orientations, are for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0060] like Figure 1 As shown, a beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to the present invention includes the following steps:

[0061] Step S1: Based on the multi-beam detection device and the type of detection mission, generate a pre-formed beam angle set, and optimize the pre-formed beam angle set to determine the key beam angles;

[0062] Step S2: Obtain channel data based on the key beam angle, perform near-field compensation focusing calculation on the channel data for each key beam angle, and obtain several key beam angle focusing signals;

[0063] Step S3: Perform Fast Fourier Transform on several key beam angle focusing signals, and then reassemble the key beam angle focusing signals after Fast Fourier Transform to obtain beam domain signals.

[0064] Step S4: Output beam domain signal for subsequent imaging processing.

[0065] This invention optimizes the pre-formed beam angle set according to a key beam angle selection strategy to determine the key beam angles. Then, it uses these key beam angles to perform near-field compensation focusing calculations and Fast Fourier Transform on the acquired channel data. This reduces the computational complexity of beamforming while avoiding a decrease in spatial resolution and imaging quality. Through this method, computational complexity is reduced by 40%-60% in near-field imaging scenarios.

[0066] In this embodiment of the invention, step S1 specifically includes:

[0067] Step S11: Determine the pre-formed beam angle set according to the detection mission requirements and the equipment parameters of the multi-beam detection device; the detection mission requirements include the type of detection mission and the detection mission opening angle range;

[0068] Step S11 specifically includes:

[0069] Step S111: Calculate the pre-formed beam angular resolution based on the equipment parameters of the multi-beam detection device, expressed as:

[0070] Let the aperture of the sensor array of the multibeam detector be D, and the operating wavelength be λ. Then the beam angular resolution Δθ of the multibeam detector satisfies:

[0071] Δθ=arcsin(λ / D)

[0072] In the field of sonar detection, the sensor array can be a sonar array; in the field of radar detection, the sensor array can be a radar antenna array.

[0073] Step S112: Based on the detection mission's opening angle range and the calculated beam angle resolution Δθ, determine the number of pre-formed beam angles and generate a set of pre-formed beam angles; for several pre-formed beam angles in the set of pre-formed beam angles, the beam angle interval between two adjacent pre-formed beam angles is an integer multiple of the beam angle resolution Δθ, and the coverage range of several pre-formed beam angles is not less than the detection mission's opening angle range.

[0074] Through the above steps, the set of preformed beam angles covering the detection mission's opening angle range is determined, and the detection results are determined to cover the target area of ​​the detection mission. This ensures that the channel data obtained based on the optimized key beam angles meet the requirements of the detection mission, thereby ensuring the accuracy of the beamforming results.

[0075] Step S12: Optimize the pre-formed beam angle set according to the type of detection mission to determine the key beam angle.

[0076] Step S12 specifically includes:

[0077] Based on the high-efficiency mode required for the detection mission, the pre-formed beam angle set is evenly divided using a uniform angular spacing method. Then, a pre-formed beam angle is selected as the key beam angle from each of the divided subsets. This high-efficiency mode shortens the data processing flow, thereby improving data processing efficiency. For example, if the pre-formed beam angle set contains 512 pre-formed beam angles and the number of key beam angles is set to 16, then each key beam angle can provide data information within a maximum of 512 / 16 = 32 beam ranges. Dividing the pre-formed beam angle set using a uniform angular spacing method, the first subset contains pre-formed beam angles numbered 1-32, and the pre-formed beam angle with number 16 is selected as the first key beam angle; the second subset contains pre-formed beam angles numbered 33-64, and the pre-formed beam angle with number 48 is selected as the second key beam angle, and so on, until the key beam angle selection for all subsets is completed. The selected key beam angle is used to map and stitch together the key beam angle focusing signal after fast Fourier transform to obtain the beam domain signal.

[0078] Based on the high-resolution mode requirement of the detection mission, a high-resolution mode optimization strategy was adopted to select the key beam angle, specifically including:

[0079] Based on the key area range angle requirements, the pre-formed beam angle set is divided into a key area angle set and a non-key area angle set. The key area range angle requirement is the range covered by the key area range angle offset to both sides of the center of the target area of ​​the channel. By determining the key area and non-key areas of the target area, a dense strategy is adopted in the key area and a sparse strategy is adopted in the non-key area, which can achieve a balance between high resolution and data processing efficiency.

[0080] Within the key area angle set, several first pre-formed beam angles are selected using a uniform angle spacing method according to the first key beam angle interval; within the non-key area, several second pre-formed beam angles are selected using a uniform angle spacing method according to the second key beam angle interval; the first key beam angle interval is smaller than the second key beam angle interval, and both the first and second pre-formed beam angles are integer multiples of the beam angle resolution.

[0081] Preferably, the angle of the key area can be 30-45°.

[0082] In step S12, the number of key beam angles can be determined based on experience and equipment performance. For example, when the detection mission requires high efficiency mode, the number of key beam angles can be set to 16; when the detection mission requires high resolution mode, the number of key beam angles for the key area angle set can be set to 12, and the number of key beam angles for the non-key area angle set can be set to 4.

[0083] Because the transducer aperture of image sonar receivers is relatively small, the edge angle imaging resolution requirement is lower when the detection distance is short. Therefore, it is unnecessary to use dense beam angles in non-interest areas. For example, the area within ±45° of the direct frontal field of view can be designated as the key area, and a denser beam angle spacing can be used to obtain higher angular resolution. Conversely, areas outside 90° of the field of view can be designated as non-key areas, employing a sparse angle selection strategy and utilizing a sparser beam angle spacing to reduce computational load.

[0084] Therefore, when optimizing the pre-formed beam angle set in the above manner, assuming the system channel number A is 96, the number of pre-formed beam angles B in the pre-formed beam angle set is 512, the number of key beam angles P is set to 16, the maximum number of beams K between two adjacent key beam angles is 512 / 16=32, and the system uses IQ sampling, the following can be calculated based on the above conditions:

[0085] Using the traditional algorithm, the output signal of each target beam is obtained by weighting and summing the signals collected from A channels. The maximum computational cost per sampling point (i.e., calculating the output of B beams from a set of data from A channels at the same time) is:

[0086] Multiplying complex numbers by the number of additions: A × B = 96 × 512 = 49152

[0087] In this invention, each subarray of the sensor array contains 3 array elements. To form one subarray signal, 3 complex multiplications are required (i.e., the weighting coefficients are multiplied by the complex signals of the array elements and then summed). The sensor array has a total of 32 subarrays. The number of multiplications is: K×P×3 = 32×16×3 = 1536.

[0088] The FFT uses a uniformly spaced key beam angle, and the number of complex multiplications in the FFT is: P×(K / 2)×log2(K) = 16×(32 / 2)×log2(32) = 1280;

[0089] The total number of complex numbers multiplied by the cumulative sum is: 1536 + 1280 = 2816.

[0090] As can be seen, the beamforming method based on preformed beam angle near-field compensation and FFT acceleration provided by this invention has a computational load of only 5.73% of that of traditional algorithms, which can significantly reduce the complexity of signal processing and improve signal processing efficiency.

[0091] In this embodiment of the invention, step S2 specifically includes:

[0092] Step S21: Establish a near-field propagation model and calculate the time delay difference from each element in the sensor array to the aggregation point;

[0093] Step S22: Perform time delay compensation on the channel data of the echo signal;

[0094] Step S23: Perform weighted summation on the channel data after time delay compensation to generate the focusing signal corresponding to the key beam angle.

[0095] In this embodiment of the invention, in step S21, the time delay difference is used to compensate for the differences in propagation paths from different array elements to the target, specifically including:

[0096] Let N be the number of array elements in the sensor array and M be the number of key beam angles. θ The coordinates of the focal point are The coordinates of the nth array element are The key beam angle The time delay difference is

[0097]

[0098] Where m represents the index of the critical beam angle, To measure the propagation speed of sonar detection signals, The reference array element position.

[0099] In this embodiment of the invention, in step S22, the channel data of the nth array element is rotated using a phase rotation method. Phase compensation is performed to adjust the phase of the channel data, offsetting the phase shift caused by path differences, and ensuring that the signals of each array element are superimposed in phase at the focal point. This is represented as:

[0100]

[0101] in, This refers to the channel data of the nth array element after phase compensation. Represents the imaginary unit. Represents different sampling points of the signal. For carrier frequency.

[0102] In this embodiment of the invention, in step S23, the key beam angle The corresponding key beam angle focusing signal is represented as follows:

[0103]

[0104] in, The element weighting coefficient for the nth element is used to suppress sidelobes or optimize beam shape.

[0105] In this embodiment of the invention, step S3 specifically includes:

[0106] Step S31: Perform an M-point FFT operation on the key beam angle focusing signal to obtain beam domain data. , is represented as:

[0107]

[0108] in, 0, 1, ... M-1 correspond to different beam directions within the critical beam angle. ;

[0109] The number of points M in the FFT operation and the number of key beam angles M θ Satisfy: M*M θ ≥ The preset number of beams for multi-beam detection devices, such as M*M θ ≥512.

[0110] Step S32: Perform zero-filling and interpolation processing on the beam domain data to improve the resolution of the beam domain data.

[0111] By employing zero-filling and interpolation, the beam domain resolution is improved to the 0.1° level, while the computation time is reduced from O(M) to O(M). 2 ) decreases to O(MlogM).

[0112] like Figure 2 As shown, the present invention provides a beamforming system based on preformed beam angle near-field compensation and FFT acceleration, including a preformed beam angle selection module 1, a focusing calculation module 2, an FFT calculation module 3, a power supply module 4, and a dynamic clock gating module 5.

[0113] The preformed beam angle selection module 1 is used to generate a set of preformed beam angles based on the multi-beam detection device and the type of detection mission, and to optimize the set of preformed beam angles to determine the key beam angles.

[0114] The focusing calculation module 2 is electrically connected to the preformed beam angle selection module 1 and the multi-beam detection device, and is used to perform near-field compensation focusing calculation based on the key beam angle to obtain several key beam angle focusing signals.

[0115] FFT calculation module 3 is electrically connected to focus calculation module 2 and is used to perform fast Fourier transform calculation on the key beam angle focus signal to obtain the beam domain signal.

[0116] The power supply module 4 is electrically connected to the pre-formed beam angle selection module 1, the focusing calculation module 2, and the FFT calculation module 3, and is used to supply power to the pre-formed beam angle selection module 1, the focusing calculation module 2, and the FFT calculation module 3.

[0117] The dynamic clock gating module 5, connected to the power supply module 4, sends an FFT power-off control signal to the power supply module 4 according to the inactive calculation period. The inactive calculation period refers to the period when the system is not working or has no echo signal.

[0118] The beamforming system based on preformed beam angle near-field compensation and FFT acceleration is implemented on an FPGA platform and uses a pipelined architecture to process channel data. Through a dynamic clock gating module 5, an FFT power-off control signal is sent to the power supply module 4 during inactive computing cycles, shutting down the FFT module and reducing power consumption by 27%. In a test on an underwater sonar system, the imaging frame rate increased from 8Hz to 15Hz, while power consumption decreased from 9.6W to 5.8W, verifying the advantages of this method in terms of real-time performance and energy efficiency.

[0119] Furthermore, it should be noted that the present invention can be provided as a method, apparatus, or computer program product. Therefore, embodiments of the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0120] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0121] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal equipment to cause a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0122] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0123] Finally, it should be noted that the above description represents a preferred embodiment of the present invention. It should be pointed out that although preferred embodiments have been described, those skilled in the art, once they understand the basic inventive concept of the present invention, can make various improvements and modifications without departing from the principles described herein. These improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A beamforming method based on preformed beam angle near-field compensation and FFT acceleration, characterized in that, Includes the following steps: Step S1: Based on the multi-beam detection device and the type of detection mission, generate a pre-formed beam angle set, and optimize the pre-formed beam angle set to determine the key beam angles; Step S2: Obtain channel data based on the key beam angle, and perform near-field compensation focusing calculation on the channel data for each key beam angle to obtain several key beam angle focusing signals; Step S3: Perform Fast Fourier Transform on several key beam angle focusing signals, and then reassemble the key beam angle focusing signals after Fast Fourier Transform to obtain beam domain signals. Step S4: Output the beam domain signal for subsequent imaging processing.

2. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 1, characterized in that, Step S1 specifically includes: Step S11: Determine the pre-formed beam angle set according to the detection mission requirements and the equipment parameters of the multi-beam detection device; the detection mission requirements include the type of detection mission and the detection mission opening angle range; Step S12: Optimize the pre-formed beam angle set according to the detection mission type to determine the key beam angle.

3. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 2, characterized in that, Step S11 specifically includes: Step S111: Calculate the pre-formed beam angular resolution based on the equipment parameters of the multi-beam detection device, expressed as: Let the aperture of the sensor array in the multi-beam detector be D, and the operating wavelength be λ. Then the beam angular resolution Δθ of the multi-beam detector satisfies: Δθ=arcsin(λ / D) Step S112: Based on the detection mission's opening angle range and the calculated beam angle resolution Δθ, determine the number of pre-formed beam angles and generate a set of pre-formed beam angles; for several pre-formed beam angles in the set of pre-formed beam angles, the beam angle interval between two adjacent pre-formed beam angles is an integer multiple of the beam angle resolution Δθ, and the coverage range of several pre-formed beam angles is not less than the detection mission's opening angle range.

4. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 3, characterized in that, Step S12 specifically includes: Based on the high-efficiency mode required by the detection mission, the preformed beam angle set is divided equally using a uniform angular spacing method, and a preformed beam angle is selected from each of the equally divided subsets as the key beam angle. Based on the high-resolution mode requirement of the detection mission, a high-resolution mode optimization strategy was adopted to select the key beam angle, specifically including: Based on the key area requirements of the detection mission, the pre-formed beam angle set is divided into a key area angle set and a non-key area angle set; Within the set of key area angles, several first pre-formed beam angles are selected using a uniform angle spacing method according to the first key beam angle interval; within the non-key area, several second pre-formed beam angles are selected using a uniform angle spacing method according to the second key beam angle interval. The first critical beam angle spacing is smaller than the second critical beam angle spacing, and both the first pre-formed beam angle and the second pre-formed beam angle are integer multiples of the beam angle resolution.

5. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 2, characterized in that, Step S2 specifically includes: Step S21: Establish a near-field propagation model and calculate the time delay difference between each element in the sensor array of the multi-beam detection device and the aggregation point; Step S22: Perform time delay compensation on the channel data; Step S23: Perform a weighted summation on the channel data after time delay compensation to generate the focusing signal corresponding to the pre-formed beam angle.

6. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 5, characterized in that, Step S21 specifically includes: Let N be the number of array elements in the sensor array and M be the number of key beam angles. θ The coordinates of the focal point are The coordinates of the nth array element are The key beam angle The time delay difference is Where m represents the index of the critical beam angle, To measure the propagation speed of sonar detection signals, The reference array element position.

7. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 6, characterized in that, In step S22, phase rotation is used to process the channel data of the nth array element. Phase compensation is represented as: in, This refers to the channel data of the nth array element after phase compensation. Represents the imaginary unit. Represents different sampling points of the signal. For carrier frequency.

8. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 7, characterized in that, In step S23, the key beam angle The corresponding key beam angle focusing signal is represented as follows: in, The element weighting coefficient for the nth element is used to suppress sidelobes or optimize beam shape.

9. The beamforming method based on preformed beam angle near-field compensation and FFT acceleration according to claim 8, characterized in that, Step S3 specifically includes: Step S31: Perform an M-point FFT operation on the key beam angle focusing signal to obtain beam domain data. , is represented as: in, 0, 1, ... M-1, corresponding to different beam directions within the critical beam angle. ; The number of points M in the FFT operation and the number of key beam angles M θ Satisfy: M*M θ ≥ The preset number of beams for multi-beam detection devices; Step S32: Perform zero-filling and interpolation processing on the beam domain data to improve the resolution of the beam domain data.

10. A beamforming system based on preformed beam angle near-field compensation and FFT acceleration, used to implement the beamforming method based on preformed beam angle near-field compensation and FFT acceleration as described in any one of claims 1 to 9, characterized in that, include: The pre-formed beam angle selection module is used to generate a set of pre-formed beam angles based on the multi-beam detection device and the type of detection mission, and to optimize the set of pre-formed beam angles to determine the key beam angles. The focusing calculation module is used to perform near-field compensation focusing calculation based on the key beam angle to obtain several key beam angle focusing signals; The FFT calculation module is used to perform fast Fourier transform calculation on the key beam angle focusing signal to obtain the beam domain signal; The power supply module is electrically connected to the pre-formed beam angle selection module, the focusing calculation module, and the FFT calculation module, and is used to supply power to the pre-formed beam angle selection module, the focusing calculation module, and the FFT calculation module; A dynamic clock gating module, connected to the power supply module, sends an FFT shutdown control signal to the power supply module according to the inactive calculation cycle.

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