Underwater focusing strong sound system based on phase control

Abstract

The utility model discloses an underwater focusing intense sound system based on phase control, which relates to the technical field of focusing intense sound, and is characterized in that a measurement and control upper computer is used for controlling emission and detection of trigger signals; the phase control signal generator is used for controlling a phase control signal of sound wave emission; the multi-channel power amplifier is used for driving the acoustic emission phased area array, and the acoustic emission phased area array is used for emitting acoustic waves; the area array calibration hydrophone is used for receiving signals of reflected sound waves; the target calibration sound source is used for transmitting a signal pulse width, the target sound field measurement hydrophone is used for receiving the signal pulse width transmitted by the target calibration sound source and forwarding the signal pulse width to the measurement and control upper computer, and the measurement and control upper computer receives the forwarded signal pulse width for system evaluation and correction. According to the utility model, through generating a high-energy strong-focusing sound field and combining with an actual underwater signal propagation process, accurate positioning and control of the underwater strong sound field can be completed, thereby realizing accurate focusing irradiation and high-resolution imaging of a long-distance small target.

Description

Technical Field

[0001] This utility model relates to the field of focused high-intensity sound technology, and more specifically, to an underwater focused high-intensity sound system based on phase control. Background Technology

[0002] In imaging detection, not only is a large emitted sound power required from the illuminating sound source, but a large emission angle is also necessary, which is technically difficult to achieve simultaneously. Increasing the emission power requires increasing the volume of the sound source, but this leads to a decrease in the emission angle. Current underwater long-range small target imaging detection research based on single sound source illumination mainly relies on increasing the emission power of the sound source to obtain the scattered signal of the small target and achieve the detection purpose. However, due to the small emission angle causing the illuminating target to be out of focus and the large sound propagation loss at long distances, it is often impossible to obtain the echo signal of the small target.

[0003] A phased array is composed of multiple transmitting units. Multiple sound sources are arranged according to a certain pattern and excited at different times. The sound waves excited by each source have a certain phase difference when propagating in the medium, so that the phases are consistent when they reach the target node and the signals are coherently superimposed. This method of generating sound waves is called the phased method. At the same time, these multiple sound sources are collectively called phased sound sources. By adjusting the emission phase difference of each unit, the energy is focused on the target point, and the target point is tracked and the target area is scanned. One of the main purposes of using phased sound sources is to generate a sound beam whose direction can be controlled. Compared with the spherical waves excited by point sound sources, the energy of the sound beam is more concentrated, it propagates farther in the medium, and it scatters more strongly on small obstacles.

[0004] The phased array concept is relatively mature in the field of radar, and strong acoustic phased array technology has also made great progress. However, in the field of underwater acoustics, due to the complexity of the transmission environment and the difference in propagation principles, the phased array method has higher requirements for the condition settings of the imaging system and the data processing method. In terms of method design and actual performance, there is still a big gap before it is mature for application.

[0005] Therefore, the present invention aims to provide an underwater focusing high-intensity acoustic system based on phase control to solve the above problems. Utility Model Content

[0006] The purpose of this invention is to provide an underwater focusing high-intensity acoustic system based on phase control. By combining the actual underwater signal propagation process, this invention can achieve precise positioning and control of the underwater high-intensity acoustic field, thereby realizing the focusing and enhancement effect of sound waves, and achieving precise focusing illumination and high-resolution imaging of small targets at long distances.

[0007] The above-mentioned technical objective of this utility model is achieved through the following technical solution: an underwater focusing high-intensity acoustic system based on phase control, comprising a phased-array signal generator, a multi-channel power amplifier, a power supply, an acoustic emission phased array, multiple array calibration hydrophones, a data acquisition unit, a target calibration sound source, a driver, a target sound field measurement hydrophone, and a measurement and control host computer; the measurement and control host computer is used to set measurement and control parameters, control the emission and detection trigger signals, and record and display the results; the phased-array signal generator is used to receive the emission signals from the measurement and control host computer. The system generates a phase control signal for controlling the emission of acoustic waves using signals and phase control parameters. A multi-channel power amplifier receives and amplifies the phase control signal from the phase control signal generator to drive the acoustic emission phased array. A power supply provides power to the multi-channel power amplifier. The acoustic emission phased array receives the phase control signal relayed by the multi-channel power amplifier to emit acoustic waves. A hydrophone for array calibration receives the signal of reflected acoustic waves. The data acquisition unit converts the signal of reflected acoustic waves received by the array calibration hydrophone into a digital signal and sends it to the measurement and control host computer.

[0008] The target calibration sound source is set at the center of the target to transmit signal pulse width. The driver is used to drive the target calibration sound source to operate. The target sound field measurement hydrophone is set at the center of the target to receive the signal pulse width transmitted by the target calibration sound source and forward it to the measurement and control host computer. The measurement and control host computer receives the signal pulse width forwarded by the target sound field measurement hydrophone for system evaluation and correction.

[0009] The present invention is further configured such that: four hydrophones are used to collect the pulse width of the emitted signal of the acoustic emission phased array.

[0010] The present invention is further configured such that the target acoustic field measuring hydrophone is a scalar hydrophone or a vector hydrophone.

[0011] This utility model also provides an underwater focusing high-intensity acoustic method based on phase control, including the following steps:

[0012] S1. The main control unit receives and processes data from the inertial navigation and GPS systems, and generates serial port commands.

[0013] S2. The main trigger unit receives the serial port command from the main control host computer and triggers the sound source signal generator and the positioning hydrophone data receiving module.

[0014] S3. The sound source signal generator generates a sound signal, which is amplified by a single sound source power amplifier and then emitted by a phased array sound source.

[0015] S4. The hydrophone array receives sound waves, and the acoustic detection and acquisition unit collects and sends the data to the data storage.

[0016] S5. The phased array sound source control host computer processes data, calculates phased delay parameters, and controls the phased array sound source signal generator.

[0017] S6. The phased-array acoustic signal generator generates and transmits phased-array acoustic signals.

[0018] S7. The acoustic detection and acquisition unit collects data of the phased array acoustic signal and sends it to the data storage device.

[0019] S8. Repeat steps S1-S7 to continue the detection.

[0020] In summary, this utility model has the following beneficial effects:

[0021] 1. This utility model provides an underwater focusing system and method based on phase control, which can flexibly control the focusing point to achieve multi-layer and multi-depth focusing on small target surfaces. In practical applications, it can achieve strong sound focusing of more than 210dB. It solves the problem of various attenuation problems that occur during the underwater propagation of sound waves emitted by acoustic arrays. It avoids diffusion attenuation caused by sound beam diffusion, scattering attenuation caused by acoustic impedance through different medium cross sections, and absorption attenuation caused by viscous force between particles inside the medium. These problems weaken the sound signal energy, resulting in reduced sensitivity of echo detection and deterioration of imaging resolution.

[0022] 2. According to the designed phased delay algorithm, this utility model uses hardware programming language to realize the regular transmission of multiple sound sources, generating pulse signals with different phases but the same frequency. Under the conditions of low power supply voltage, strong transmission signal of individual transducers, and good consistency between sound source channels, it can achieve precise time delay control with an error within 25ns. The minimum resolution of the phased delay signal can reach 10ps. This lays a good foundation for realizing high-quality underwater imaging and coping with complex underwater environments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the principle of phased-array focused high-intensity sound in this embodiment of the present invention;

[0024] Figure 2 This is a flowchart illustrating the phased-controlled sound source measurement and control system in an embodiment of this utility model.

[0025] Figure 3 This is a schematic diagram of the time delay setting of the phased-controlled sound source measurement and control system in this embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram and actual image of the T-shaped phased-controlled sound source measurement and control system in this embodiment of the utility model;

[0027] Figure 5This is a schematic diagram of the overall operation of the phased-controlled sound source measurement and control system in this embodiment of the utility model;

[0028] Figure 6 This is a connection diagram of the phase-controlled sound source measurement and control system in an embodiment of this utility model;

[0029] Figure 7 This is a schematic diagram of the working process of the phased-controlled sound source measurement and control system in this embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the maximum sound source level test results for each channel and each operating frequency in this embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the minimum resolution of the phase-controlled delay signal in an embodiment of this utility model;

[0032] Figure 10 This is a schematic diagram of the channel delay control accuracy test results in an embodiment of this utility model;

[0033] Figure 11 This is a schematic diagram of the received waveform and amplitude of the linear frequency modulated sound signal in the channel according to an embodiment of this utility model;

[0034] Figure 12 This is a schematic diagram of the received waveforms of 18 channels of linear frequency modulation (FM) sound signals in an embodiment of this utility model;

[0035] Figure 13 This is a schematic diagram of the pulse compression results of 18 channels of linear frequency modulated acoustic signals in this embodiment of the present invention;

[0036] Figure 14 This is a schematic diagram of the single-channel acoustic signal pulse compression result in an embodiment of this utility model;

[0037] Figure 15 This is a schematic diagram of the phase-controlled focusing amplitude results in an embodiment of this utility model;

[0038] Figure 16 This is a schematic diagram of the standard hearing sensitivity measurement data and curves in an embodiment of this utility model.

[0039] In the diagram: 1. Phased signal generator; 2. Multi-channel power amplifier; 3. Acoustic emission phased array; 4. Array calibration hydrophone; 5. Data acquisition unit; 6. Driver; 7. Measurement and control host computer; 8. Calibration sound source; 9. Target sound field measurement hydrophone. Detailed Implementation

[0040] The following is in conjunction with the appendix Figure 1-16 The present invention will be described in further detail below.

[0041] Example 1: An underwater focusing high-intensity acoustic system based on phase control, comprising a phased-array signal generator 1, a multi-channel power amplifier 2, a power supply, an acoustic emission phased array 3, four array calibration hydrophones 4, a data acquisition unit 5, a target calibration sound source, a driver 6, a target sound field measurement hydrophone 9, and a measurement and control host computer 7; the measurement and control host computer 7 is used to set measurement and control parameters, control the emission and detection trigger signals, and record and display the results; the phased-array signal generator 1 is used to receive the emission signal and phased-array parameters from the measurement and control host computer 7, and generate signals to control the sound wave emission. The phase control signal of the phased array is received by the phased array signal generator 1 and amplified to drive the acoustic emission phased array 3. The power supply provides power to the multi-channel power amplifier 2. The acoustic emission phased array 3 receives the phase control signal forwarded by the multi-channel power amplifier 2 and is used to emit sound waves. Four array calibration hydrophones 4 are used to receive the signal of reflected sound waves and to collect the pulse width of the emitted signal of the acoustic emission phased array 3. The data acquisition unit 5 converts the signal of reflected sound waves received by the array calibration hydrophones into a digital signal and sends it to the measurement and control host computer 7.

[0042] The target calibration sound source is set at the center of the target to transmit signal pulse width. The driver 6 is used to drive the target calibration sound source to run. The target sound field measurement hydrophone 9 is set at the center of the target to receive the signal pulse width transmitted by the target calibration sound source and forward it to the measurement and control host computer 7. The measurement and control host computer 7 receives the signal pulse width forwarded by the target sound field measurement hydrophone 9 for system evaluation and correction.

[0043] Example 2: An underwater focusing acoustic method based on phase control, comprising the following steps:

[0044] Data synchronization: The main control unit receives and processes data from inertial navigation and GPS, and generates serial port commands;

[0045] Signal triggering: The main triggering unit receives serial port commands from the main control host computer and triggers the sound source signal generator and the positioning hydrophone data receiving module;

[0046] Signal amplification and transmission: The sound source signal generator produces a sound signal, which is amplified by a single sound source power amplifier and then transmitted by a phased array sound source;

[0047] Signal reception and acquisition: The hydrophone array receives sound waves, and the acoustic detection and acquisition unit acquires and sends the data to the data storage device;

[0048] Data processing and control: The phased array sound source control host computer processes data, calculates phased delay parameters, and controls the phased array sound source signal generator;

[0049] Phased signal transmission: The phased sound source signal generator generates and transmits phased array sound signals;

[0050] Data acquisition and storage: The acoustic detection acquisition unit acquires data of the phased array acoustic signals and sends them to the data storage device;

[0051] Loop: Repeat the above steps to continuously perform sonar detection.

[0052] Example 3: Test Experiment of Phased Sound Source Measurement and Control System

[0053] A phased array acoustic source, also known as a phase-compensated (or time-delay compensated) acoustic emission array, works by appropriately phase-shifting (or delaying) the signals from acoustic emission transducer elements arranged in a specific pattern to achieve beam deflection, thereby enabling precise positioning and control of the sound field. The precise beamforming of a phased array acoustic source results in a high sound level within a specified space; furthermore, through precise phase and time delay control, phased array acoustic sources can achieve beam scanning and tracking within a desired spatial range, such as... Figure 1 As shown, the origin of the phased array coordinates is at the center of the array, and the number of phased acoustic emission units (fixed in the system) is N. The coordinates of each phased acoustic emission unit are {Xi,Yi}N. A calibration sound source 8S0 and a phased acoustic field measurement hydrophone D0 are installed at the center of the target.

[0054] In this embodiment, a phase-controlled underwater focusing acoustic system from Example 1 is used as the phase-controlled acoustic source measurement and control system for testing. The working principle of this phase-controlled acoustic source measurement and control system is as follows: Figure 2 As shown, the time delay setting of its phased-controlled sound source measurement and control system is as follows: Figure 3 As shown, the schematic diagram and actual images of the T-shaped phased-controlled sound source measurement and control system are as follows. Figure 4 As shown in the diagram, the overall working schematic of the phased-array sound source measurement and control system is as follows: Figure 5 As shown.

[0055] In this embodiment, according to Figure 6 Connect the test system, connect the digital signal source output to the super-resolution phased array sound source signal generator trigger input, output DC pulse signal with pulse width of 2%, signal period of 1Hz, high level 5V, low level 0V.

[0056] The analog command and control terminal is connected to the super-resolution phased array acoustic source signal generator via a gigabit network cable. Acoustic emission digital signals are written into the analog command and control terminal's host computer software. The signal frequencies are 70kHz, 75kHz, 80kHz, 85kHz, 90kHz, 95kHz, 100kHz, 105kHz, 110kHz, 115kHz, and 120kHz, with a signal length of 2ms and an amplitude of 1.7V. The host computer software sequentially transmits the acoustic emission digital signals. The frequency and amplitude of the acoustic signals received by a standard hydrophone are observed and measured using an oscilloscope. When the frequency of the received signal from the standard hydrophone matches the frequency of the transmitted signal, the formula for calculating the sound source level is as follows:

[0057] M0 = 20 * lgV0 - M s+20*lgS

[0058] Wherein: source level: M0; signal amplitude received by standard hydrophone: V0; standard hydrophone sensitivity: M s Standard hydrophone and transducer distance: S.

[0059] In this embodiment, the test setup was conducted at the test site according to the scenario described above. After the equipment was tested and confirmed to be operating normally, the test implementation steps were carried out as follows:

[0060] 1) The pulse width of the signal emitted by the phased-array sound source and the target center calibration sound source 8 is △T=1ms, and the pulse width of the phased-array sound field measurement hydrophone D0 and the positioning hydrophone D1~4 is T=20ms;

[0061] 2) Initial target distance: R (initial value setting);

[0062] 3) The acoustic emission signal of the S0 acoustic source on the target is calibrated;

[0063] 4) The phased array is equipped with 4 positioning hydrophones. The acquisition time delay td = R / V - 10ms (generated by the system) is used to acquire the signal and obtain the time delay td1~4 of each hydrophone. The location r of the calibration sound source is then determined.

[0064] 5) Based on the position r of the calibrated sound source 8, calculate the time delay ti of each phased sound source relative to the target center, and calculate the new time delay Δti = ti(Max) - ti;

[0065] 6) Phased transmission: Upon trigger arrival, each phased sound source transmits according to the time delay Δti, and the system outputs the phased center time delay correction ti(Max);

[0066] 7) The sound intensity level at the center of the target is obtained by delaying the hydrophone D0 by t0 = r / v - 10ms, and the sound intensity level at the center of the target is calculated based on the received signal;

[0067] 8) Focused beamwidth measurement: When determining the target center r, the focusing center is successively offset by xi, and focusing is performed at the offset point. The sound intensity at the target center hydrophone D0 and the sound intensity at -xi are measured. Multiple measurements are taken to obtain the focused beamwidth curve (one-dimensional offset) or intensity map (two-dimensional offset). The focused beamwidth is then calculated.

[0068] 9) Phased array scanning: Given the location of the scanning center region, the focal point is shifted regularly around this center to complete the region scan;

[0069] 10) Tracking and Focusing: Based on the changing target points given in the implementation, focusing on the target points completes the tracking;

[0070] 11) Read the maximum sound intensity of the receiving array;

[0071] 12) Record the test results and determine whether the target requirements have been met.

[0072] The working sequence of each device in the phased-array sound source measurement and control system of this embodiment is as follows: Figure 7 As shown.

[0073] Experimental data

[0074] This embodiment involves on-site inspection. The system controls a total of 72 transmitting units (in practical applications, 20 units are sufficient to meet the requirements, with 18 units for phase control and 2 units for positioning). Its sound source level test is as follows: Figure 8 As shown, the time delay resolution is as follows: Figure 9 As shown, the channel delay control accuracy test was conducted by selecting any three phased-array acoustic waveform signals and setting the delays of the three channels to 1*1 / 48M, 2*1 / 48M, and 3*1 / 48M, respectively. The test results are as follows. Figure 10 As shown, the curves match well, indicating high accuracy.

[0075] In the initial phase measurement and correction of phased-array sound sources, each phased-array sound source emits with a time delay of Δti + 5ms × i. The phased-array measurement hydrophone D0 measures the actual time delay ti,dti = ti - 5ms × i of each phased-array sound source signal, which is the initial phase and correction of the phased-array sound source. The results are as follows: Figure 11-14 As shown, the initial phase measurement and correction results are shown in Table 1:

[0076] Table 1. Initial Phase Measurement and Correction Results

[0077]

[0078]

[0079] In phased-array acoustic source focusing, the measured initial phase error of the phased-array acoustic source is corrected into the phased-array parameters. The phased-array focusing results of 18 linear frequency modulated signals are as follows: Figure 15 As shown.

[0080] The amplitude of the standard listening received signal for a single channel of the sound source array is 0.32–0.33 Vpp. Sensitivity measurement data and curves are shown below. Figure 16 As shown.

[0081] By setting different delay parameters, this embodiment can obtain the following phased array focusing sound intensity test results, as shown in Table 2-6:

[0082] Table 2 Time Delay Parameter Group 1 and Focused Sound Intensity Results

[0083]

[0084]

[0085] Table 3 Time Delay Parameter Group 2 and Focused Sound Intensity Results

[0086]

[0087] Table 4. Time Delay Parameter Group 3 and Focused Sound Intensity Results

[0088]

[0089]

[0090] Table 5. Results of Time Delay Parameter Group 4 and Focused Sound Intensity

[0091]

[0092]

[0093] Table 6 Time Delay Parameter Group 5 and Focused Sound Intensity Results

[0094]

[0095] Conclusion: By adjusting the phase of the signals transmitted by each sound source in the phased array sound source, the receiving array receives an accurate focused signal. The measured sound intensity values ​​show a clear increase in signal strength, and the focused sound intensity is greater than 210dB.

[0096] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

Claims

1. An underwater focusing high-intensity acoustic system based on phase control, characterized in that: The system includes a phased-array signal generator (1), a multi-channel power amplifier (2), a power supply, a phased-array acoustic emission array (3), multiple array calibration hydrophones (4), a data acquisition unit (5), a target calibration sound source, a driver (6), a target acoustic field measurement hydrophone (9), and a measurement and control host computer (7). The measurement and control host computer (7) is used to set measurement and control parameters, control the emission and detection trigger signals, and record and display the results. The phased-array signal generator (1) is used to receive the emission signal and phased-array parameters from the measurement and control host computer (7) and generate a signal for controlling the emission of acoustic waves. Phase control signal; the multi-channel power amplifier (2) receives the phase control signal from the phase control signal generator (1) and amplifies it to drive the acoustic emission phased array (3); the power supply provides power to the multi-channel power amplifier (2); the acoustic emission phased array (3) receives the phase control signal forwarded by the multi-channel power amplifier (2) to emit sound waves; the array calibration hydrophone (4) is used to receive the signal of reflected sound waves; the data acquisition unit (5) converts the signal of reflected sound waves received by the array calibration hydrophone into a digital signal and sends it to the measurement and control host computer (7); The target calibration sound source is set at the center of the target to transmit signal pulse width. The driver (6) is used to drive the target calibration sound source to run. The target sound field measurement hydrophone (9) is set at the center of the target to receive the signal pulse width transmitted by the target calibration sound source and forward it to the measurement and control host computer (7). The measurement and control host computer (7) receives the signal pulse width forwarded by the target sound field measurement hydrophone (9) for system evaluation and correction.

2. The underwater focusing acoustic system based on phase control according to claim 1, characterized in that: The array calibration hydrophone (4) is set to 4 units, which are used to collect the pulse width of the emitted signal of the acoustic emission phased array (3).

3. The underwater focusing acoustic system based on phase control according to claim 1, characterized in that: The target acoustic field measurement hydrophone (9) is a scalar hydrophone or a vector hydrophone.

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