Receiving and transmitting reconstruction multi-beam sonar control method and receiving and transmitting reconstruction multi-beam sonar system

Abstract

The invention discloses a receiving and transmitting reconstruction multi-beam sonar control method and a receiving and transmitting reconstruction multi-beam sonar system, the sonar system comprises a first transducer and a second transducer, the first transducer is used for executing fan-shaped sound wave emission to a target area; the second transducer is a linear array comprising a plurality of array elements, and each array element is selectively connected to the receiving channel or the transmitting channel through the change-over switch; the control method comprises the following steps: controlling the first transducer to emit fan-shaped sound waves, and controlling the linear array to be in a receiving state so as to receive a first echo signal; when a target object is found, the linear array is switched to be in an emission state, and all or part of array elements in the linear array are controlled to act so as to emit focused sound waves towards the target object. According to the control method of the sonar system, through the time division multiplexing linear array, on the premise that the physical aperture is not increased, working mode conversion from fan-shaped wide beam searching to focused narrow beam detailed searching is achieved, and the detection efficiency of the sonar system is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of sonar detection technology, and in particular to a transceiver reconfiguration multibeam sonar control method and a transceiver reconfiguration multibeam sonar system. Background Technology

[0002] Multibeam sonar systems, as efficient underwater detection tools, are widely used in seabed topography mapping, underwater target search, and marine engineering. Traditional multibeam sonar systems typically employ a physically separate transmit and receive mode, namely an architecture of "transmitting a single arc-shaped transducer and receiving an equally spaced linear array." In this architecture, the single arc-shaped transmitting transducer is responsible for transmitting sound waves covering a wide sector underwater in a single pass, while the independent receiving linear array is responsible for receiving the echo signal and performing subsequent signal processing using beamforming technology to obtain sonar images.

[0003] However, existing traditional multibeam sonar technology has significant limitations in practical applications. Because its transmitter typically uses only a single curved wafer for wide-area transmission, the energy distribution of the emitted beam is uniform in all directions. This dispersed energy characteristic makes it impossible to concentrate energy when targeting specific small targets or regions of interest (ROIs) requiring focused attention. Limited by the physical aperture of the receiving array and the fixed beamwidth, existing systems often face problems of low signal-to-noise ratio and insufficient angular resolution when detecting small or distant targets. This makes it difficult to achieve fine characterization and high-resolution imaging of specific areas, and fails to meet the flexible detection requirements from "global coarse measurement" to "local fine measurement." Summary of the Invention

[0004] The purpose of this invention is to provide a transceiver reconfiguration multibeam sonar control method and a transceiver reconfiguration multibeam sonar system with dual modes of global coarse measurement and local fine measurement.

[0005] To achieve the above objectives, this invention provides a transceiver reconfiguration multibeam sonar control method, applied to a sonar system. The sonar system includes a first transducer and a second transducer. The first transducer is used to transmit fan-shaped acoustic waves towards a target area. The second transducer is a linear array containing multiple array elements. Each array element is selectively connected to either a transmit channel or a receive channel via a switching switch to achieve switching between transmit and receive states. The control method includes: The first transducer is controlled to emit a fan-shaped sound wave, while the linear array is controlled to be in a receiving state to receive the first echo signal. When a target is detected based on the first echo signal, the linear array is switched to the transmission state, and beamforming weights are generated according to the position of the target. Based on the beamforming weights, the operation of all or some of the array elements in the linear array is controlled to emit focused sound waves toward the target object; After the focused acoustic wave transmission ends, the linear array is controlled to switch to receiving mode to receive the second echo signal; A feature map of the target object is generated based on the second echo signal.

[0006] Preferably, the method for detecting the target object includes: The first echo signal is processed to generate a full-sector sonar image; The region of interest coordinates of the target object are determined in the full-sector sonar image by means of automatic target recognition algorithm or manual selection.

[0007] Preferably, the method of emitting the focused acoustic wave includes: Based on the coordinates of the region of interest, determine the distance and azimuth of the target object relative to the second transducer; Based on the distance and azimuth angle, calculate the phase difference or time delay required for each array element in the second transducer to achieve focal coverage; Based on the phase difference or time delay, each array element is controlled to emit sound waves so that the sound waves are focused on the target object.

[0008] Preferably, the receiving channel includes a filtering module, an analog-to-digital conversion module, and a signal preprocessing module connected in sequence, and the filtering module is electrically connected to the switching switch; The method for controlling the linear array to be in a receiving state includes: Control the switching switch to connect the array element to the filtering module, so that the first echo signal or the second echo signal enters the analog-to-digital conversion module via the filtering module; The transmission channel includes a plurality of pulse generators, and the output terminals of the plurality of pulse generators are electrically connected to each of the array elements in the linear array; The method for controlling the linear array to be in a transmitting state includes: Control the switching switch to disconnect the array element from the filter module; The pulse generator generates high-voltage electrical pulses to drive the array elements according to the beamforming weights.

[0009] Preferably, the second echo signal is subjected to high-gain receiving processing and digital beamforming processing to output a feature map of the target object.

[0010] The present invention also provides a transceiver reconfiguration multibeam sonar system, comprising: The first transducer is configured to emit fan-shaped acoustic waves toward the target area; The second transducer is a linear array containing multiple array elements; A switching switch, which is connected to the array elements in the linear array, is used to selectively connect each array element to a transmit channel or a receive channel, so as to realize the switching of the linear array between the transmit state and the receive state. A control processing unit is connected to the first transducer, the second transducer, and the switching switch, respectively. The control processing unit is configured to control the operation of the switching switch in response to a generated control signal, and when the linear array is in the transmission state, to control all or part of the array elements in the linear array to emit focused sound waves toward the target object according to a pre-generated beamforming weight.

[0011] Preferably, in the linear array, each array element is configured with an independent switching switch, or all array elements are configured with a shared switching switch.

[0012] Preferably, the control processing unit is further configured to: The first echo signal received by the linear array, corresponding to the fan-shaped acoustic wave emitted by the first transducer, is processed to generate a full-sector sonar image. An automatic target recognition algorithm is used to identify or respond to a manual selection operation to determine the region of interest coordinates of the target object in the full-sector sonar image. Based on the region of interest coordinates, the distance and azimuth of the target object relative to the linear array are determined. Based on the distance and azimuth, the phase difference or time delay required for each array element in the linear array to achieve focal coverage is calculated. The beamforming weights are generated based on the phase difference or time delay.

[0013] Preferably, the receiving channel includes a filtering module, an analog-to-digital conversion module, and a signal preprocessing module connected in sequence, and the filtering module is connected to the switching switch; The transmission channel includes a pulse generator connected to the array element; The switching switch is configured to: in the receiving state, connect the array element to the filtering module so that the echo signal enters the analog-to-digital conversion module via the filtering module; in the transmitting state, disconnect the array element from the filtering module.

[0014] Preferably, the first transducer is a single-element arc array.

[0015] Compared with existing technologies, the transceiver reconfiguration multibeam sonar control method provided by the above-mentioned technical solution, in general, achieves flexible switching between wide-area search and local precision measurement through a transceiver reconfiguration architecture. Specifically, after the target is identified, a linear array is used for focused transmission, concentrating acoustic energy on the target area, significantly suppressing sidelobe interference, and greatly improving the echo signal-to-noise ratio and angular resolution, effectively solving the problems of energy dispersion and weak detection capability of small or long-range targets in traditional sonar. At the same time, this solution achieves functional upgrades through time-division multiplexing without increasing the physical array size, balancing detection efficiency and imaging accuracy, and has significant advantages such as high hardware integration and low modification cost. Attached Figure Description

[0016] Figure 1 This is a planar structural diagram of the transducer of the sonar system in an embodiment of the present invention.

[0017] Figure 2 This is a circuit diagram adapted to the second transducer in an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the first transducer in the transmitting state in an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the second transducer in the transmitting state in an embodiment of the present invention.

[0020] Figure 5 This is a flowchart of the sonar control method in an embodiment of the present invention. Detailed Implementation

[0021] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0022] This embodiment provides a method for controlling a transceiver reconfigurable multibeam sonar, which is applied to a sonar system for detecting underwater conditions.

[0023] like Figure 1 and Figure 2 As shown, the sonar system includes a first transducer 100, a second transducer 200, and a control and processing unit connected to both. The first transducer 100 is used to perform fan-shaped sound wave transmission towards the target area, and is typically a transmitting array with wide beam coverage or a single high-power transmitter. Furthermore, the first transducer 100 is a single-element arc array.

[0024] The second transducer 200 is a linear array L containing multiple array elements P (e.g., N array elements P, N≥3).

[0025] In this configuration, each array element P of the second transducer 200 is not fixedly connected to a single channel, but is selectively connected to either the transmit channel Tr or the receive channel Re via a switching switch K (e.g., a high-voltage transceiver switch T / R switch). This connection method enables the linear array L to dynamically switch between transmit and receive states.

[0026] The control processing unit is responsible for generating control commands to drive the first transducer 100, the second transducer 200, and the switching switch K to operate.

[0027] Based on this, please refer to the following: Figure 1 , Figure 2 and Figure 5 The control method specifically includes the following steps: S1: Wide-area search phase.

[0028] Control the first transducer 100 to emit fan-shaped sound waves (such as...) Figure 3 This fan-shaped acoustic wave typically covers a large angular range (e.g., a horizontal fan of 120°) for rapid scanning. Simultaneously, the switching switch K is activated, connecting each element P in the linear array L to the receiving channel Re, thus putting the linear array L into a receiving state. At this time, the linear array L acts as a receiving array, receiving the first echo signal emitted by the first transducer 100 and reflected back from the environment.

[0029] S2: Target confirmation and parameter calculation.

[0030] The control processing unit processes the received first echo signal. When a target object M (e.g., an underwater shipwreck, a school of fish, or a specific terrain feature) is detected based on the first echo signal, the system enters the reconstruction preparation phase. At this time, the system no longer transmits fan-shaped waves, but instead calculates the spatial coordinates of the target M relative to the sonar system based on the position of the target M in the sonar image, and generates beamforming weights accordingly. These weights include delay parameters or phase parameters used to control the transmission phase of each array element P.

[0031] S3: Focused launch phase.

[0032] At this point, the linear array L is controlled to enter a transceiver mode. Specifically, firstly, the switching switch K is activated to disconnect the linear array L from the receiving channel Re and connect it to the transmitting channel Tr, thereby switching the linear array L into a transmitting state. Based on the beamforming weights generated in step S2, all or some of the array elements P in the linear array L are controlled to operate. Specifically, a specific phase difference or time delay is applied to the excitation signal of each array element P, causing the emitted sound waves to interfere and superimpose in space, thereby emitting highly concentrated focused sound waves (such as...) towards the target object M. Figure 4 ).

[0033] S4: Focus on the receiving phase.

[0034] Within a very short time (typically milliseconds) after the focused acoustic wave emission pulse ends, the switching switch K is activated again to switch the linear array L back to the receiving state. At this time, the linear array L once again acts as a receiving array, receiving the second echo signal reflected back from the target object M after the focused acoustic wave illuminates it.

[0035] S5: Feature imaging.

[0036] A feature map of the target M is generated based on the second echo signal. Because the transmitting end uses a focused beam, the illumination energy is concentrated and the sidelobes are low, so the generated feature map has a higher signal-to-noise ratio and resolution than that in step S1, and can clearly present the detailed features of the target.

[0037] This embodiment achieves a switching of working mode from wide-beam fan-shaped search to focused narrow-beam detailed investigation without increasing the physical aperture by using a time-division multiplexed linear array L, effectively improving the detection efficiency of the sonar system.

[0038] Specifically, unlike traditional multibeam sonar which relies solely on the receiver for beamforming, this embodiment utilizes a linear array L for beamforming (focused transmission) at the transmitter. By precisely controlling the transmission phase or delay of each array element P, the acoustic energy is spatially directed into a narrow beam that directly illuminates the target object M. This dual-focusing mechanism, combining transmitter-focusing with receiver-beamforming, significantly compresses the beamwidth, effectively suppresses sidelobe interference, and thus significantly improves the system's angular resolution. This results in a clearer feature map of the target object M compared to images acquired through traditional fan-shaped transmission, revealing richer details.

[0039] Furthermore, this method combines the advantages of two different transducers. The fan-shaped emission of the first transducer 100 rapidly covers a large area, ensuring detection efficiency (no missed scans); once a suspicious target is detected, the reconfigurable characteristics of the linear array L are immediately utilized for focused, detailed investigation. This step-by-step control logic avoids the enormous time cost and data processing pressure associated with full-area high-resolution scanning, while also addressing the pain point of traditional wide-area searches failing to capture details, achieving a perfect balance between detection efficiency and accuracy.

[0040] In a preferred embodiment, each of the array elements P in the linear array L is configured with an independent switching switch K.

[0041] Assume a linear array L contains N array elements P, and the system circuit board integrates N independent switching switches K. The i-th array element P is directly connected to the i-th switching switch K.

[0042] The control processing unit is connected to the control terminal of each switching switch K through N independent control lines (or through serial bus addressing).

[0043] This independent distributed switch configuration offers extremely high flexibility and fault tolerance. If a switch in a certain channel fails (such as contact sticking), the control processing unit can isolate that channel independently without affecting the operation of the remaining array elements P.

[0044] In another preferred embodiment, a common switching switch K is configured for all the array elements P in the linear array L.

[0045] A multi-channel high-voltage analog switch integrated circuit or a multi-pole relay group is used as a common switching switch K. This common switching switch K has N independent input / output channel pairs, but shares the same logic control interface. Although the signal paths of all array elements P are physically packaged through the same component or module, the signal transmissions are isolated from each other and do not interfere with each other.

[0046] The control processing unit only needs to output one global control signal to the logic input of the shared switching switch K.

[0047] In this shared integrated switch configuration, when the control signal flips, the actions of all array elements P switching from the receiving state to the transmitting state (or vice versa) are strictly synchronized in time, eliminating the switching timing jitter between channels and helping to ensure the phase consistency of the focused beam.

[0048] In another embodiment, the method for discovering the target object M in step S2 above specifically includes: 1. Generation of full-sector images.

[0049] First, the first echo signal acquired in step S1 is subjected to conventional beamforming processing (such as time-domain delay summation beamforming) to generate a full-sector sonar image covering the entire sector detection area. This image typically has low resolution and is mainly used to observe macroscopic contours.

[0050] 2. Determine the Target Area (ROI).

[0051] There are two modes for determining the coordinates of the region of interest: Automatic mode: The system runs an Automatic Target Recognition (ATR) algorithm, such as a constant false alarm rate (CFAR) detector or a pre-trained convolutional neural network (CNN), to automatically detect bright outliers or targets that conform to specific geometric features in the image and output their center coordinates and bounding boxes.

[0052] Manual mode: Operators manually specify the area to be investigated in detail on the sonar image displayed on the control terminal by clicking with the mouse or selecting with a touch box. The system maps the screen coordinates back to the sonar polar coordinate system to determine the region of interest coordinates of the target object M.

[0053] In another embodiment, the specific steps for emitting the focused acoustic wave in step S3 above are as follows: 1. Geometric parameter calculation: Based on the region of interest coordinates determined in the above embodiments, the distance R and azimuth angle θ of the target object M relative to the center of the second transducer 200 (linear array L) are calculated.

[0054] 2. Delay Calculation: Based on the distance and azimuth angle, calculate the phase difference or time delay required for each array element P in the second transducer 200 to achieve focal coverage.

[0055] 3. Array element P-driven: The control processing unit sends the calculated phase difference or time delay to the FPGA logic of the transmission channel Tr. The FPGA controls the multi-channel pulse generator to trigger high-voltage pulses strictly according to the delay sequence of each array element P. For example, for a target 50 meters away at an azimuth of 30°, the edge array element P may transmit approximately X microseconds earlier than the center array element P, thus ensuring that the acoustic wavefronts of all array elements P converge precisely at 30° at 50 meters, forming a high-intensity focal point.

[0056] Another embodiment, such as Figure 2 The receiving channel Re includes a filtering module (such as a bandpass filter with a center frequency matching the sonar operating frequency), an analog-to-digital converter (ADC), and a signal preprocessing module (such as a digital down-conversion DDC) connected in sequence. The input terminal of the filtering module is directly electrically connected to the receiving contact of the switching switch K.

[0057] The transmission channel Tr includes several pulse generators (such as Class D power amplifiers or transformer drive circuits). The output terminals of the pulse generators are electrically connected to each of the array elements P in the linear array L.

[0058] When the system is in a receiving time slot (including receiving the first or second echo), the control processing unit outputs a control signal to the switching switch K to activate it. At this time, each array element P is connected to the filtering module. The weak echo signal is filtered, amplified, and sampled by the ADC before entering the digital domain for processing.

[0059] When the system is in the focused transmission time slot, the control processing unit outputs a high control signal to the switching switch K, causing it to activate. At this time, each array element P is disconnected from the filter module (to protect the low-voltage receiving circuit). The pulse generator generates a high-voltage electrical pulse according to the aforementioned beamforming weights (delay parameters) to drive the array element P to vibrate and produce sound.

[0060] Furthermore, in step S5 above, the processing flow for the second echo signal is as follows: 1. High-gain reception: Since focused transmission is mainly aimed at a specific small area, the receiver can use a targeted time gain control (TVG) curve to amplify the signal in the target range.

[0061] 2. Digital beamforming: Beamforming processing is performed on the acquired multi-channel digital signals. Since physical focusing has been achieved at the transmitting end, the beamforming at the receiving end can be further performed using a dynamic focusing algorithm, that is, the receiving focus is dynamically adjusted with the echo time to ensure that it always coincides with the echo position.

[0062] 3. Feature map output: The processed data is mapped to grayscale or pseudo-color images. Compared to the full-sector image generated by the first echo, the feature map generated based on the second echo has a higher signal-to-noise ratio (SNR) and a narrower main lobe width (higher angular resolution). This feature map can be overlaid on the full-sector image as a picture-in-picture or displayed separately for users to identify the fine structure of the target (such as the mast of a shipwreck, the shape of cracks in a pipe, etc.).

[0063] In summary, in a typical implementation, it is assumed that the first transducer 100 operates at a frequency of 400kHz; the second transducer 200 is a linear array L of 128 elements P with a spacing of 1.8mm between the elements P.

[0064] Wide-area search: The first transducer 100 emits a CW pulse with a pulse width of 0.1ms, with a detection range of 100m.

[0065] Detailed Focusing: Upon detecting a target at (30m, 15°), switch K switches its state within 1ms. After calculating the delay, the control processing unit controls 128 array elements P to emit a focused beam, with the focus set at 30m. The received second echo is processed, improving the target resolution at 30m from the usual 0.5m to 0.1m, clearly displaying the target's outline features.

Claims

1. A method for controlling a multibeam sonar that can be reconfigured for transceiver transmission, characterized in that, The method is applied to a sonar system, which includes a first transducer and a second transducer. The first transducer is used to transmit fan-shaped sound waves towards a target area. The second transducer is a linear array containing multiple array elements, each of which is selectively connected to a receiving channel or a transmitting channel (integrated transceiver channel) via a switching switch to achieve switching between transmitting and receiving states of the linear array. The control method includes: The first transducer is controlled to emit a fan-shaped sound wave, while the linear array is controlled to be in a receiving state to receive the first echo signal. When a target is detected based on the first echo signal, the linear array is switched to the transmission state, and beamforming weights are generated according to the position of the target. Based on the beamforming weights, the operation of all or some of the array elements in the linear array is controlled to emit focused sound waves toward the target object; After the focused acoustic wave transmission ends, the linear array is controlled to switch to receiving mode to receive the second echo signal; A feature map of the target object is generated based on the second echo signal.

2. The multibeam sonar control method for transceiver reconfiguration according to claim 1, characterized in that, The methods for detecting the target object include: The first echo signal is processed to generate a full-sector sonar image; The region of interest coordinates of the target object are determined in the full-sector sonar image by means of automatic target recognition algorithm or manual selection.

3. The multibeam sonar control method for transceiver reconfiguration according to claim 2, characterized in that, The method of emitting the focused sound wave includes: Based on the coordinates of the region of interest, determine the distance and azimuth of the target object relative to the second transducer; Based on the distance and azimuth angle, calculate the phase difference or time delay required for each array element in the second transducer to achieve focal coverage; Based on the phase difference or time delay, each of the array elements is controlled to emit sound waves so that the sound waves are focused on the target object; Based on the signals mentioned above, image processing and algorithm reconstruction are performed to form a clearer sonar image.

4. The multibeam sonar control method for transceiver reconfiguration according to claim 1, characterized in that, The receiving channel includes a filtering module, an analog-to-digital conversion module, and a signal preprocessing module connected in sequence, and the filtering module is electrically connected to the switching switch; The method for controlling the linear array to be in a receiving state includes: Control the switching switch to connect the array element to the filtering module, so that the first echo signal or the second echo signal enters the analog-to-digital conversion module via the filtering module; The transmission channel includes a plurality of pulse generators, and the output terminals of the plurality of pulse generators are electrically connected to each of the array elements in the linear array; The method for controlling the linear array to be in a transmitting state includes: Control the switching switch to disconnect the array element from the filter module; The pulse generator generates high-voltage electrical pulses to drive the array elements according to the beamforming weights.

5. The multibeam sonar control method for transceiver reconfiguration according to claim 1, characterized in that, The second echo signal is subjected to high-gain reception processing and digital beamforming processing to output a feature map of the target object.

6. A transceiver reconfigurable multibeam sonar system, characterized in that, include: The first transducer is configured to emit fan-shaped acoustic waves toward the target area; The second transducer is a linear array containing multiple array elements; A switching switch, which is connected to the array elements in the linear array, is used to selectively connect each array element to a transmit channel or a receive channel, so as to realize the switching of the linear array between the transmit state and the receive state. A control processing unit is connected to the first transducer, the second transducer, and the switching switch, respectively. The control processing unit is configured to control the operation of the switching switch in response to a generated control signal, and when the linear array is in the transmission state, to control all or part of the array elements in the linear array to emit focused sound waves toward the target object according to a pre-generated beamforming weight.

7. The transceiver reconfiguration multibeam sonar system according to claim 6, characterized in that, In the linear array, each array element is configured with an independent switching switch, or all array elements are configured with a shared switching switch.

8. The transceiver reconfiguration multibeam sonar system according to claim 6, characterized in that, The control processing unit is further configured to: The first echo signal received by the linear array, corresponding to the fan-shaped acoustic wave emitted by the first transducer, is processed to generate a full-sector sonar image. An automatic target recognition algorithm is used to identify or respond to a manual selection operation to determine the region of interest coordinates of the target object in the full-sector sonar image. Based on the region of interest coordinates, the distance and azimuth of the target object relative to the linear array are determined. Based on the distance and azimuth, the phase difference or time delay required for each array element in the linear array to achieve focal coverage is calculated. The beamforming weights are generated based on the phase difference or time delay.

9. The transceiver reconfiguration multibeam sonar system according to claim 6, characterized in that, The receiving channel includes a filtering module, an analog-to-digital conversion module, and a signal preprocessing module connected in sequence, and the filtering module is connected to the switching switch. The transmission channel includes a pulse generator connected to the array element; The switching switch is configured to: in the receiving state, connect the array element to the filtering module so that the echo signal enters the analog-to-digital conversion module via the filtering module; in the transmitting state, disconnect the array element from the filtering module.

10. The transceiver reconfiguration multibeam sonar system according to claim 6, characterized in that, The first transducer is a single-element arc array.

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