An array element-based sonar monopulse three-dimensional imaging method, storage medium and electronic device

Abstract

The application belongs to underwater acoustic detection technology, and particularly relates to a sonar single-pulse three-dimensional imaging method based on an array element, a storage medium and an electronic device. The method comprises the following steps: constructing a transmitting-receiving array element system, a first array element transmits and receives signals, and the remaining array elements only receive signals, a rectangular coordinate system is established with the first array element as the origin, and the remaining array elements are located on the coordinate axes; a single echo signal is obtained after a transmitted signal is reflected by a single detection target and received by a pth array element, and frequency domain sampling signals of the single echo signal are obtained through orthogonal mixing, pulse compression and Fourier transform processing; the frequency domain sampling signals of the pth array element are the sum of frequency sampling signals of echo signals at M distance gates; the distance of the detection target to the array element is calculated according to the frequency domain sampling signals, the included angle of the detection target with x, y and z is obtained according to a geometric relationship, and a three-dimensional imaging result of the detection target is determined. The application can realize three-dimensional imaging with a single pulse, reduces manufacturing cost, and has low requirements on the moving precision of the sensor.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of underwater acoustic detection, and particularly relates to a sonar single-pulse three-dimensional imaging method based on an array element, a storage medium and an electronic device. BACKGROUND

[0002] The sonar is an electronic device for detecting, positioning and communicating underwater targets by using underwater acoustic waves, and is the most widely used and most important device in underwater acoustics. It uses the propagation characteristics of acoustic waves underwater, and through electro-acoustic conversion and information processing, it completes the detection, positioning and communication of underwater targets, judges the existence, position and type of objects in the ocean, and is also used for underwater information transmission.

[0003] The multi-beam imaging algorithm is one of the main research directions of sonar imaging. After the array signal is collected, the signal needs to be processed through beam forming technology to obtain effective information. The directivity of the system in a certain direction is obtained by processing the array signal, and the azimuth information of the signal is obtained through the directivity. The multi-beam sonar system usually uses a linear array or a planar array composed of multiple array elements. Compared with a small aperture array, a large aperture array has higher resolution. A typical multi-beam sonar system may include several tens to several hundred array elements. A large size array will bring a burden on space and weight, and increase the cost and process complexity of the transducer.

[0004] The synthetic aperture sonar technology uses a small aperture array to synthesize a virtual large aperture array by sailing the sonar carrier, which can obtain high resolution in the track direction without increasing the physical array burden. However, the conventional synthetic aperture sonar usually adopts a dual-amplitude array side-scan mode, which will cause a detection gap in the area directly below the carrier platform, and can only perform two-dimensional imaging. Since SAS relies on the accurate movement of the sensor, the stability of the platform and the navigation accuracy are crucial to the system performance, and it may be difficult to use in high sea conditions or unstable environments.

[0005] Although the multi-beam sonar system can provide high-resolution and wide-coverage underwater images, in order to improve the resolution, a large-size array is usually required, which brings a burden on space and weight, and increases the cost and process complexity of the transducer.

[0006] Although the synthetic aperture sonar technology can achieve high-resolution imaging by using a small aperture array and sailing, it can only perform two-dimensional imaging. This technology requires high accuracy of sensor movement and platform stability, and its performance is limited in high sea conditions or unstable environments. SUMMARY

[0007] In view of the problems in the prior art, the application provides a sonar single-pulse three-dimensional imaging method based on array elements, a storage medium and an electronic device, a new transmitting-receiving array element system is adopted, three-dimensional imaging can be realized by using a single pulse, and the manufacturing cost is greatly reduced; and high-resolution imaging is realized without using the sailing mode, and the sensor movement precision requirement is low.

[0008] In the embodiment of the application, the technical scheme of the three-dimensional imaging method is as follows:

[0009] S1, a transmitting-receiving array element system is constructed, including P array elements, wherein a first array element transmits and receives signals; the remaining array elements except the first array element only receive signals and do not transmit signals; a rectangular coordinate system is established with the first array element as the origin, and the remaining array elements are located on the coordinate axes of the rectangular coordinate system;

[0010] S2, a linear frequency modulation signal is used as a transmitted signal, and after the transmitted signal is reflected by a single detection target, a single echo signal is received by the pth array element, wherein 1≤p≤P;

[0011] S3, the single echo signal is subjected to quadrature mixing processing; the output signal after the quadrature mixing is subjected to pulse compression, and after Fourier transform, a frequency domain sampling signal of the single echo signal is obtained;

[0012] S4, in the established rectangular coordinate system, the positions with the same echo time delay τ of the detection target to the pth array element are the same distance gate, assuming that the pth array element has M distance gates, and each distance gate contains one or more detection targets; the frequency domain sampling signal of the pth array element is represented as the sum of the frequency sampling signals of the echo signals from the M distance gates;

[0013] S5, the distance gate of the detection target to the first array element is determined according to the frequency domain sampling signal of the first array element, and is used as the distance of the detection target to the first array element; the frequency domain sampling signal of the first array element is multiplied by the conjugate signal of the frequency domain sampling signal of the p'th array element, to obtain a signal after conjugate multiplication; the signal after conjugate multiplication is subjected to Fourier transform, to obtain the echo time delay difference of the detection target to the first array element and the p'th array element; according to the echo time delay difference, the path difference of the detection target to the first array element and the p'th array element is obtained; according to the path difference, the distance of the detection target to the p'th array element is calculated, wherein 2≤p'≤P;

[0014] S6, connecting the position of the detection target and the first array element in the rectangular coordinate system to obtain a target array element line; based on the distance from the detection target to the first array element, the distance from the detection target to the remaining array elements other than the first array element, and the distance between the first array element and the remaining array elements other than the first array element, the angle between the target array element line and the x-axis, the y-axis and the z-axis is obtained according to the geometric relationship; the three-dimensional imaging result of the detection target is determined according to the angle between the target array element line and the x-axis, the y-axis and the z-axis.

[0015] In the embodiment of the present application, the technical scheme adopted by the storage medium is: a storage medium, which stores computer instructions, when the computer instructions are executed by a processor, the steps of the sonar single-pulse three-dimensional imaging method in the embodiment of the present application are realized.

[0016] In the embodiment of the present application, the technical scheme adopted by the electronic device is: an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, when the processor executes the computer program, the steps of the sonar single-pulse three-dimensional imaging method in the embodiment of the present application are executed.

[0017] Compared with the prior art, the technical effects obtained by the present application include:

[0018] The present application constructs a transmitting and receiving array element system, and establishes a rectangular coordinate system with the first array element in the transmitting and receiving array element system as the center, and the remaining array elements are located on the coordinate axes of the rectangular coordinate system. Therefore, the present application can realize three-dimensional imaging with a single pulse, greatly reducing the manufacturing cost, and does not need to realize high-resolution imaging by sailing, and has low requirements on the moving precision of the sensor. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The flowchart of the sonar single-pulse three-dimensional imaging method based on array elements in the embodiment of the present application;

[0020] Figure 2 The distribution diagram of all distance gates of the first array element and the second array element in the embodiment of the present application;

[0021] Figure 3 The schematic diagram of the wave path difference of the three detection targets to the first array element and the second array element in the embodiment of the present application;

[0022] Figure 4 The imaging effect diagram of the target in the embodiment of the present application, wherein (a) is the actual target model, and (b) is the imaging result;

[0023] Figure 5 The imaging effect diagram of the letter A in the embodiment of the present application, wherein (a) is the actual target model, and (b) is the imaging result. DETAILED DESCRIPTION

[0024] The application will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the application are not limited thereto.

[0025] Embodiment

[0026] The embodiment provides a single-pulse three-dimensional imaging method of an array element-based sonar, as shown in the figure, comprising the following steps: Figure 1

[0027] S1, constructing a transceiving array element system comprising P array elements, wherein a first array element transmits and receives signals; the rest of the array elements except the first array element only receive signals without transmitting signals; a rectangular coordinate system is established with the first array element as the center (i.e. the origin), and the rest of the array elements are located on the coordinate axes of the rectangular coordinate system.

[0028] In the embodiment, the transceiving array element system comprises four array elements, the first array element is denoted as Tx / Rx0, the second array element, the third array element and the fourth array element are denoted as Rx1, Rx2 and Rx3 respectively; a rectangular coordinate system is established with the first array element Tx / Rx0 as the center, and the coordinates of Rx1, Rx2 and Rx3 are (L1, 0, 0), (0, L2, 0) and (0, 0, L3) respectively, i.e. the second array element, the third array element and the fourth array element are located on the x-axis, the y-axis and the z-axis respectively, wherein L1, L2 and L3 are the distances from Rx1, Rx2 and Rx3 to the origin of the rectangular coordinate system respectively.

[0029] S2, using a linear frequency modulation signal as a transmission signal, and obtaining a single echo signal by receiving the transmission signal reflected by a single detection target by a pth array element, wherein 1≤p≤P.

[0030] In the embodiment, the transmission signal can be represented as:

[0031] s(t)=A t exp[j(2πf0t+kπt 2 )],t∈[-T / 2,T / 2] (1)

[0032] The echo signal is received by an array element, and the array elements receiving the echo signal can be collectively referred to as receiving array elements, i.e. the receiving array element can be the first array element or the second, third or fourth array element. The single echo signal can be represented as:

[0033] s r (t)=A r exp[j(2πf0(t-τ)+kπ(t-τ) 2 )],t∈[-T / 2,T / 2] (2)

[0034] wherein A t is the amplitude of the transmission signal, A r ​is the amplitude of the single echo signal, f0is the signal center frequency, T is the signal pulse width, B is the signal bandwidth, k=B / T is the signal frequency variation rate, τ is the echo delay experienced by the signal from being transmitted to detecting the target and then returning to the receiving array element, τ=r / c, r is the distance traveled by the signal from being transmitted to detecting the target and then returning to the receiving array element, and c is the speed of light.

[0035] S3, performing quadrature mixing processing on the single echo signal; performing pulse compression on the output signal after the quadrature mixing, and then performing Fourier transform to obtain a frequency domain sampling signal of the single echo signal.

[0036] In this embodiment, the output signal of the single echo signal (i.e., the single received signal) after the quadrature mixing is:

[0037] s b (t)=A b exp[-j2π(f0τ+kτt)] (3)

[0038] The frequency domain sampling signal of the single echo signal can be expressed in the following form:

[0039] S(f)=A c exp(-j2πf0τ)exp(j2πnΔfτ) (4)

[0040] wherein A b is the amplitude of the output signal after the quadrature mixing, A c is the amplitude of the frequency domain sampling signal, n=0, 1, …, N-1 is the frequency domain sampling serial number, and Δf is the frequency sampling interval.

[0041] S4, in the established rectangular coordinate system, the positions with the same echo delay τ of the detecting target to the pth array element are the same distance gate, assuming that the pth array element has M distance gates, and each distance gate contains one or more detecting targets; the frequency domain sampling signal of the pth array element can be expressed as the sum of the frequency sampling signals of the echo signals from the M distance gates.

[0042] In this embodiment, the frequency domain sampling signal S p of the pth array element can be expressed in the following form:

[0043] S p =z p,1 exp(-j2πnΔfτ p,1 )exp(-j2πf0τ p,1 )+…

[0044] +z p,m exp(-j2πnΔfτ p,m )exp(-j2πf0τ p,m )+…

[0045] +z p,M exp(-j2πnΔfτ p,M )exp(-j2πf0τ p,M ) (5)

[0046] wherein m represents the mth range gate of the pth array element, 1≤m≤M; z p,m represents the amplitude of the single frequency sampling signal at the mth range gate of the pth array element, τ p,m represents the echo time delay experienced by the signal from the pth array element to the detection target at the mth range gate and back to the pth array element.

[0047] That is, after the all echo signals received by the pth array element after being reflected by all detection targets are orthogonally mixed and pulse compressed one by one, the frequency domain sampling signal of the pth array element can be obtained.

[0048] For the convenience of understanding, it is first assumed that the detection targets are all at the same range gate r0with respect to the first array element Tx / Rx0(i.e. the echo time delays of all detection targets to the first array element are the same), as shown in FIG. 1. Figure 2 wherein r 1k is the distance from the first array element Tx / Rx0to the detection target k, r 11 = r 12 =…= r 1K = r0; r 2k is the distance from the second array element Rx1to the detection target k. The frequency domain sampling signal S1of the first array element Tx / Rx0and the frequency domain sampling signal S2of the second array element Rx1are respectively:

[0049] S1= z 1,1 exp(-j2πnΔfτ 1,1 )exp(-j2πf0τ 1,1 )

[0050] S2= z 2,1 exp(-j2πnΔfτ 2,1 )exp(-j2πf0τ 2,1 )+…

[0051] +z 2,m exp(-j2πnΔfτ 2,m )exp(-j2πf0τ 2,m )+…

[0052] +z 2,M exp(-j2πnΔfτ 2,K )exp(-j2πf0τ 2,M ) (6)

[0053] In the case that the target is in the same range gate of the first array element Tx / Rx0, each range gate of the second array element Rx1 contains one target, and the frequency domain sampling signal of the second array element Rx1 can be expressed as:

[0054] S2 = z 2,1 exp(-j2πnΔfτ 2,1 )exp(-j2πf0τ 2,1 )+…

[0055] +z 2,k exp(-j2πnΔfτ 2,k )exp(-j2πf0τ 2,k )+…

[0056] +z 2,K exp(-j2πnΔfτ 2,K )exp(-j2πf0τ 2,K ) (7)

[0057] wherein τ 2,k represents the echo time delay of the signal from the target to the second array element.

[0058] S5, determining the range gate of the target to the first array element according to the frequency domain sampling signal of the first array element, and taking the range gate as the distance of the target to the first array element; multiplying the frequency domain sampling signal of the first array element with the conjugate signal of the frequency domain sampling signal of the p'th array element to obtain a signal after conjugate multiplication; performing Fourier transform on the signal after conjugate multiplication to obtain the echo time delay difference of the target to the first array element and the p'th array element; obtaining the path difference of the target to the first array element and the p'th array element according to the echo time delay difference; and calculating the distance of the target to the p'th array element according to the path difference, wherein 2≤p'≤P, and the p'th array element is the remaining array element other than the first array element.

[0059] In this embodiment, after the echo signal of the first array element Tx / Rx0 is quadrature mixed and pulse compressed, the range gate r0 of the target to the first array element Tx / Rx0 can be obtained, which is the distance of the target to the first array element.

[0060] Taking the second array element (i.e. p'=2) as an example, the distance of the target to the p'th array element is calculated, which is described in detail as follows: multiplying the frequency domain sampling signal of the first array element Tx / Rx0 with the conjugate signal of the frequency domain sampling signal of the second array element Rx1 to obtain a signal after conjugate multiplication; performing Fourier transform on the signal after conjugate multiplication to obtain the echo time delay difference of the target to the first array element Tx / Rx0 and the second array element Rx1:

[0061] (τ 1,1 -τ2,1 ),…,(τ 1,1 -τ 2,k ),…,(τ 1,1 -τ 2,K ) (8)

[0062] According to the echo time delay difference, the path difference of the detection target to the first array element Tx / Rx0 and the second array element Rx1 is obtained as follows:

[0063] Δr1=c(τ 1,1 -τ 2,1 ),…,Δr K =c(τ 1,1 -τ 2,K ) (9)

[0064] The path difference is shown in FIG. 8. According to the path difference, the distance of the detection target to the second array element Rx1 can be calculated as follows: Figure 3

[0065] r 21 =r0+Δr1,…,r 2k =r0+Δr k ,…,r0+Δr K (10)

[0066] Using the same method, the distance of the detection target to the remaining array elements (for example, the third array element, the fourth array element, etc.) other than the first array element can be calculated.

[0067] S6, connecting the position of the detection target and the first array element in the rectangular coordinate system to obtain a target array element line; based on the distance of the detection target to the first array element, the distance of the detection target to the remaining array elements other than the first array element, and the distance between the first array element and the remaining array elements other than the first array element, the included angle of the target array element line with the x-axis, the y-axis and the z-axis is obtained according to the geometric relationship; and the three-dimensional imaging result of the detection target is determined according to the included angle of the target array element line with the x-axis, the y-axis and the z-axis.

[0068] Based on the distance of the detection target to the first array element Tx / Rx0 and the second array element Rx1, and the distance between the first array element Tx / Rx0 and the second array element Rx1, the included angle θ1, θ2, …, θ K of the line connecting the detection target and the first array element Tx / Rx0 (i.e. the target array element line) with the x-axis can be obtained according to the geometric relationship. Wherein the included angle θ k of the line connecting the detection target k and the first array element (i.e. the target array element line of the detection target k) with the x-axis is as follows:

[0069]

[0070] Wherein r0 is the distance gate of the detection target to the first array element, L1 is the distance of the second array element to the origin of the rectangular coordinate system; r​2k to the second array element.

[0071] Therefore, for K detection targets, the angles between their target array lines and the x-axis have K values, respectively θ1, θ2, …, θ K .

[0072] Similarly, by multiplying the frequency domain sampling signal of the first array element Tx / Rx0 with the conjugate signal of the frequency domain sampling signal of the third array element Rx2 and the fourth array element Rx3, respectively, the angles γ1, γ2, …, γ K between the connecting line between the detection target k and the first array element (i.e., the target array line of the detection target k) and the y-axis can be obtained. k

[0073]

[0074] wherein L2 is the distance from the third array element to the origin of the rectangular coordinate system; r 3k is the distance from the detection target to the third array element.

[0075] and the angles φ1, φ2, …, φ K between the connecting line between the detection target k and the first array element (i.e., the target array line of the detection target k) and the z-axis can be obtained. k

[0076]

[0077] wherein L3 is the distance from the fourth array element to the origin of the rectangular coordinate system; r 4k is the distance from the detection target to the fourth array element.

[0078] For the same detection target k, the following equation is obtained:

[0079] cos 2 θ k +cos 2 γ k +cos 2 φ k =1 (14)

[0080] By using the matching rule of equation (14), the angles between the connecting line between the same detection target and the first array element (i.e., the target array line of the same detection target) and the x, y, and z axes can be matched, and thus the three-dimensional imaging result of the detection target is obtained, i.e., the three-dimensional positioning of the detection target is obtained.

[0081] ​​When the detection target is at different distance gates for the first array element Tx / Rx0, first, the signal of each distance gate in the range corresponding to the target echo in the one-dimensional distance direction of the first array element Tx / Rx0 is extracted alone, and for the extracted single distance gate signal, the requirement that the detection target is in the same distance gate is met, and the operations of steps S5 and S6 are performed, so that the imaging result of the detection target in the distance gate is obtained; and by traversing each extracted signal, the imaging result of all targets (i.e., the cubic target) can be obtained, as shown in Figure 4 .

[0082] If the contour of an object is depicted by multiple detection targets, for example, the letter A, the imaging result is as shown in Figure 5 .

[0083] Based on the same inventive concept, the embodiment further provides a storage medium having computer instructions stored thereon, and when the computer instructions are executed by a processor, the steps S1-S6 of the sonar single-pulse three-dimensional imaging method in the embodiment are implemented.

[0084] In addition, the embodiment further provides an electronic device including a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the computer program, the steps S1-S6 of the sonar single-pulse three-dimensional imaging method in the embodiment are executed.

[0085] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principle of the present application should be equivalent replacement modes, and all are included in the protection scope of the present application.

Claims

1. A sonar single-pulse three-dimensional imaging method based on array elements, characterized in that, Includes the following steps: S1. Construct a transceiver array element system, including P array elements, where the first array element transmits and receives signals; Except for the first array element, the other array elements only receive signals and do not transmit signals; a rectangular coordinate system is established with the first array element as the origin, and the other array elements are located on the coordinate axes of the rectangular coordinate system; S2. A linear frequency modulated signal is used as the transmission signal. After the transmission signal is reflected by a single detection target, a single echo signal is received by the p-th array element, where 1≤p≤P. S3. Perform quadrature mixing on a single echo signal; The output signal after quadrature mixing is pulse compressed and then subjected to Fourier transform to obtain the frequency domain sampling signal of a single echo signal; S4. In the established rectangular coordinate system, the positions where the echo delay τ from the detected target to the p-th array element is the same range gate. Assume that the p-th array element has a total of M range gates, and each range gate contains one or more detected targets; then the frequency domain sampling signal of the p-th array element is represented as the sum of the frequency sampling signals of the echo signals from the M range gates. S5. Determine the range threshold from the target to the first array element based on the frequency domain sampling signal of the first array element, and use it as the distance from the target to the first array element; multiply the frequency domain sampling signal of the first array element with the conjugate signal of the frequency domain sampling signal of the p'th array element to obtain the conjugate multiplied signal; perform a Fourier transform on the conjugate multiplied signal to obtain the echo delay difference between the target and the first array element and the p'th array element; obtain the path difference between the target and the first array element and the p'th array element based on the echo delay difference; calculate the distance from the target to the p'th array element based on the path difference, where 2≤p'≤P; S6. Connect the location of the detected target to the first array element in a rectangular coordinate system to obtain the target array element line; based on the distance from the detected target to the first array element, the distance from the detected target to the other array elements outside the first array element, and the distance between the first array element and the other array elements outside the first array element, calculate the angle between the target array element line and the x-axis, y-axis, and z-axis according to geometric relationships; determine the three-dimensional imaging result of the detected target based on the angle between the target array element line and the x-axis, y-axis, and z-axis.

2. The sonar single-pulse three-dimensional imaging method according to claim 1, characterized in that, The transceiver array system constructed in step S1 includes four array elements, with the second, third, and fourth array elements located on the x-axis, y-axis, and z-axis, respectively.

3. The sonar single-pulse three-dimensional imaging method according to claim 1, characterized in that, The transmitted signal in step S2 is represented as follows: s(t)=A t exp[j(2πf0t+kπt 2 )],t∈[-T / 2,T / 2] The echo signal is received by array elements, and the array elements that receive the echo signal are collectively referred to as receiving array elements; a single echo signal is represented as: s r (t)=A r exp[j(2πf0(t-τ)+kπ(t-τ) 2 )],t∈[-T / 2,T / 2] Among them, A t A represents the amplitude of the transmitted signal. r Let f0 be the amplitude of a single echo signal, T be the signal center frequency, B be the signal pulse width, k = B / T be the signal frequency change rate, τ be the echo delay from transmission to the detection target and back to the receiving array element, τ = r / c, where r is the distance the signal travels from transmission to the detection target and back to the receiving array element, and c is the speed of light.

4. The sonar single-pulse three-dimensional imaging method according to claim 3, characterized in that, The output signal of a single echo signal after quadrature mixing in step S3 is: s b (t)=A b exp[-j2π(f0τ+kτt)] The frequency domain sampled signal of a single echo signal is represented as: S(f)=A c exp(-j2πf0τ)exp(j2πnΔfτ) Among them, A b A is the amplitude of the output signal after quadrature mixing. c Let n be the amplitude of the frequency domain sampled signal, n = 0, 1, ..., N-1 be the frequency domain sampling number, and Δf be the frequency sampling interval.

5. The sonar single-pulse three-dimensional imaging method according to claim 4, characterized in that, The frequency domain sampling signal S of the p-th array element in step S4 p Represented as: S p =z p,1 exp(-j2πnΔfτ p,1 )exp(-j2πf0τ p,1 )+…+z p,m exp(-j2πnΔfτ p,m )exp(-j2πf0τ p,m )+…+z p,M exp(-j2πnΔfτ p,M )exp(-j2πf0τ p,M ) Where m represents the m-th distance gate of the p-th array element, 1≤m≤M; z p,m τ represents the amplitude of a single frequency sampled signal at the m-th distance gate of the p-th array element. p,m This represents the echo delay experienced by the signal from transmission to the target at the m-th distance gate and back to the p-th array element.

6. The sonar single-pulse three-dimensional imaging method according to claim 1, characterized in that, Suppose there are K detection targets, the second array element is located on the x-axis, and the angle θ between the target element line of target k and the x-axis is... k for: Where r0 is the distance gate from the detected target to the first array element, and L1 is the distance from the second array element to the origin of the Cartesian coordinate system; 2k To detect the distance from the target to the second array element; The third element is located on the y-axis, and the angle γ between the target element line for detecting target k and the y-axis is... k for: Where L2 is the distance from the third element to the origin of the rectangular coordinate system; r 3k To detect the distance from the target to the third array element; The fourth array element is located on the z-axis, and the angle φ between the target array element line for detecting target k and the z-axis is... k for: Where L3 is the distance from the fourth element to the origin of the rectangular coordinate system; r 4k To detect the distance from the target to the fourth array element; For the same detection target k, the following equation holds: cos 2 i k +cos 2 c k +cos 2 f k =1 Using the matching rules of the equation, the angles between the target element lines of the same detection target and the x, y, and z axes are matched to obtain the three-dimensional imaging result of the detection target.

7. The sonar single-pulse three-dimensional imaging method according to claim 1, characterized in that, When the detected target is at different range gates relative to the first array element, the signal of each range gate within the range corresponding to the target echo in the one-dimensional range direction of the first array element is extracted separately. For the extracted signal of a single range gate, if the requirement that the detected target is within the same range gate is met, the processing steps S5 and S6 are performed to obtain the imaging result of the detected target within that range gate. Each extracted signal is traversed to obtain the imaging result of all targets.

8. A storage medium storing computer instructions thereon, characterized in that, When the computer instructions are executed by the processor, they implement the steps of the sonar monopulse three-dimensional imaging method according to any one of claims 1-7.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it performs the steps of the sonar monopulse three-dimensional imaging method according to any one of claims 1-7.

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