A phase control based underwater focused intense sound system and method

Abstract

The application discloses a kind of underwater focusing strong acoustic system and method based on phase control, it is related to focusing strong acoustic technical field, and its technical solution main point is: control emission and detection trigger signal is used for control host computer;The phase control signal for controlling acoustic wave emission is used for the phased signal generator;The multi-channel power amplifier is used for driving acoustic emission phased array, and the acoustic emission phased array is used for emitting acoustic wave;The surface array calibration hydrophone is used for receiving the signal of reflected acoustic wave;The target calibration sound source is used for emitting signal pulse width, and the target sound field measurement hydrophone is used for receiving signal pulse width emitted by target calibration sound source and forwarding to control host computer, and control host computer receives the signal pulse width forwarded for system evaluation and correction.The application can complete accurate positioning and control of underwater strong acoustic field by generating high-energy strong focusing acoustic field and combining actual underwater signal propagation process, to realize accurate focusing irradiation and high-resolution imaging of long-distance small target.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of focused intense sound technology, more particularly, it relates to an underwater focused intense sound system and method based on phase control. BACKGROUND

[0002] In imaging detection, not only is it required that the sound source has a large emission sound power, but also it needs to have a large emission angle, which is difficult to meet simultaneously in technology; increasing the emission power needs to increase the volume of the sound source, but will result in a decrease in the emission angle. The current research on underwater long-distance small target imaging detection based on single sound source irradiation takes increasing the emission power of the sound source as the main method to obtain the scattering signal of the small target to achieve the detection purpose; but because the emission angle is small, the target is out of focus, the distance is far, and the sound propagation loss is large, the echo signal of the small target is often unable to be obtained.

[0003] A phased emission array is adopted by using multiple emission units, multiple sound sources are arranged according to a certain rule, and different times are used for excitation, so that each sound source excites a sound wave with a certain phase difference when propagating in the medium, the phases of the sound waves reaching the target node are consistent, and the signals are coherently superimposed. This method of generating sound waves is called a phased method, and the multiple sound sources are collectively referred to as a phased sound source. By adjusting the emission phase difference of each unit, the energy can be focused on the target point, and the target point can be tracked and the target area can be scanned. One of the main purposes of using a phased sound source is to produce a sound beam whose direction can be controlled. Compared with the spherical wave excited by a point sound source, the energy of the sound beam is more concentrated and can propagate farther in the medium and scatter more strongly from small obstacles.

[0004] The phased array idea is more mature in the field of radar, and the strong sound phased array technology has also made great progress, but in the field of underwater sound, due to the complexity of the transmission environment and the difference in propagation principles, the phased array method has higher requirements for the condition setting and data processing method of the imaging system. There is still a big gap in method design and actual effectiveness from mature application.

[0005] Therefore, the present application aims to provide an underwater focused intense sound system and method based on phase control to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide an underwater focused intense sound system and method based on phase control. The present application can complete the accurate positioning and control of the underwater intense sound field by combining the actual underwater signal propagation process, thereby realizing the focusing and enhancing effect of sound waves, and realizing the accurate focusing and irradiation of long-distance small targets and high-resolution imaging.

[0007] The technical purposes are achieved by the following technical solutions: an underwater focusing strong acoustic system and method based on phase control, comprising a phased signal generator, a multi-channel power amplifier, a power supply, an acoustic emission phased array, a plurality of 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 for setting measurement and control parameters, controlling emission and detection trigger signals, and recording and displaying results; the phased signal generator is used for receiving emission signals and phased parameters of the measurement and control host computer, and generating phase control signals used for controlling acoustic wave emission; the multi-channel power amplifier receives the phase control signals of the phased signal generator and amplifies them, and is used for driving the acoustic emission phased array; the power supply provides electric energy for the multi-channel power amplifier; the acoustic emission phased array receives the phase control signals forwarded by the multi-channel power amplifier and is used for emitting acoustic waves; the array calibration hydrophone is used for receiving reflected acoustic wave signals; the data acquisition unit converts the reflected acoustic wave signals received by the array calibration hydrophone into digital signals and sends them to the measurement and control host computer.

[0008] The target calibration sound source is arranged at the center of the target and is used for emitting signal pulses; the driver is used for driving the target calibration sound source to operate; the target sound field measurement hydrophone is arranged at the center of the target and is used for receiving signal pulses emitted by the target calibration sound source and forwarding them to the measurement and control host computer; and the measurement and control host computer receives the signal pulses forwarded by the target sound field measurement hydrophone and is used for system evaluation and correction.

[0009] The array calibration hydrophone is arranged as four, and is used for collecting emission signal pulses of the acoustic emission phased array.

[0010] The target sound field measurement hydrophone adopts a scalar hydrophone or a vector hydrophone.

[0011] The application further provides an underwater focusing strong acoustic method based on phase control, comprising the following steps:

[0012] S1, the total control host computer receives and processes data from an inertial navigation system and a GPS, and generates a serial port instruction;

[0013] S2, the total trigger unit receives the serial port instruction of the total control host computer, and triggers a sound source signal generator and a 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 emitted by a phased array sound source;

[0015] S4, a hydrophone array receives acoustic waves, and a sound detection acquisition unit acquires and sends data to a data storage unit;

[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, the present invention has the following beneficial effects:

[0021] 1. This invention 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 current 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 invention uses hardware programming language to realize the regular transmission of multiple sound sources, generating pulse signals with different phases but the same frequency. This enables precise time delay control with an error within 25ns, under the conditions of low power supply voltage, strong transmission signals from individual transducers, and good consistency between sound source channels. The minimum resolution of the phased delay signal can reach 10ps, which lays a good foundation for achieving 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 an 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 the present invention;

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

[0026] Figure 4 These are schematic diagrams and actual images of the T-shaped phased-controlled sound source measurement and control system in an embodiment of the present invention;

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

[0028] Figure 6 This is a connection diagram of the phased-controlled sound source measurement and control system in an embodiment of the present invention;

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

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

[0033] Figure 11 This is a schematic diagram of the received waveform and amplitude of the linear frequency modulated acoustic signal in an embodiment of the present invention;

[0034] Figure 12 This is a schematic diagram of the received waveforms of 18 channels of linear frequency modulated sound signals in an embodiment of the present invention;

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

[0037] Figure 15 This is a schematic diagram of the phased array focusing amplitude results in an embodiment of the present invention;

[0038] Figure 16 This is a schematic diagram of the standard hearing sensitivity measurement data and curves in an embodiment of the present invention. Detailed Implementation

[0039] The following is in conjunction with the appendix Figures 1-16 The present invention will be described in further detail below.

[0040] Example 1: An underwater focusing high-intensity acoustic system based on phase control includes a phased array signal generator, a multi-channel power amplifier, a power supply, an acoustic emission phased array, four 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 transmission and detection trigger signals, and record and display the results. The phased array signal generator is used to receive the transmission signal and phased array parameters from the measurement and control host computer and generate a phase control signal for controlling the sound wave transmission. The multi-channel power amplifier receives and amplifies the phase control signal from the phased array signal generator to drive the acoustic emission phased array. The 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 for transmitting sound waves. The four array calibration hydrophones are used to receive the reflected sound wave signals and acquire the pulse width of the transmitted signal from the acoustic emission phased array. The data acquisition unit converts the reflected sound wave signals received by the array calibration hydrophones into digital signals and sends them to the measurement and control host computer.

[0041] 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.

[0042] Example 2: An underwater focusing acoustic method based on phase control, comprising the following steps:

[0043] Data synchronization: The main control unit receives and processes data from inertial navigation and GPS, and generates serial port commands;

[0044] 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;

[0045] 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;

[0046] 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;

[0047] 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;

[0048] Phased signal transmission: The phased sound source signal generator generates and transmits phased array sound signals;

[0049] 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;

[0050] Loop: Repeat the above steps to continuously perform sonar detection.

[0051] Example 3: Test Experiment of Phased Sound Source Measurement and Control System

[0052] 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 S0 and a phased acoustic field measurement hydrophone D0 are installed at the center of the target.

[0053] 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.

[0054] 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.

[0055] 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:

[0056] M0 = 20 * lgV0 - M s +20*lgS

[0057] Wherein: source level: M0; signal amplitude received by standard hydrophone: V0; standard hydrophone sensitivity: M s Standard hydrophone and transducer distance: S.

[0058] In this embodiment, the test setup was conducted at the test site according to the scenario described above. After the equipment was debugged and confirmed to be operating normally, the test implementation steps were carried out as follows:

[0059] 1) Pulse width of the phased-array sound source and target center calibration sound source transmission signal: ΔT = 1ms; Pulse width of the phased-array sound field measurement hydrophone D0 and the 4 positioning hydrophones D1~4: T = 20ms;

[0060] 2) Initial target distance: R (initial value setting);

[0061] 3) The acoustic emission signal of the S0 acoustic source on the target is calibrated;

[0062] 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.

[0063] 5) Based on the calibration sound source position r, 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;

[0064] 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);

[0065] 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;

[0066] 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.

[0067] 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;

[0068] 10) Tracking and Focusing: Based on the changing target points given in the implementation, focusing on the target points completes the tracking;

[0069] 11) Read the maximum sound intensity of the receiving array;

[0070] 12) Record the test results and determine whether the target requirements have been met.

[0071] 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.

[0072] Experimental data

[0073] 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.

[0074] In the initial phase measurement and correction of phased-array sound sources, each phased-array sound source emits according to 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: Figures 11-14 As shown, the initial phase measurement and correction results are shown in Table 1:

[0075] Table 1. Initial Phase Measurement and Correction Results

[0076] Sound source array channel number Initial delay parameter Distance delay parameter 1 1013 480000 2 1919 480001 3 1881 480007 4 1970 480017 5 1863 480031 6 1530 480048 7 1703 480070 8 1556 480095 9 1413 480124 10 1384 480157 11 947 480194 12 1385 480235 13 1698 480280 14 1498 480328 15 1372 480381 16 1360 480437 17 1543 480497 18 1778 480561

[0077] 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.

[0078] 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.

[0079] By setting different delay parameters, this embodiment can obtain the following phased array focusing sound intensity test results, as shown in Table 2-6:

[0080] Table 2 Time Delay Parameter Group 1 and Focused Sound Intensity Results

[0081]

[0082] Table 3 Time Delay Parameter Group 2 and Focused Sound Intensity Results

[0083]

[0084]

[0085] Table 4. Time Delay Parameter Group 3 and Focused Sound Intensity Results

[0086]

[0087]

[0088] Table 5. Results of Time Delay Parameter Group 4 and Focused Sound Intensity

[0089]

[0090] Table 6. Time Delay Parameter Group 5 and Focused Sound Intensity Results

[0091]

[0092]

[0093] 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.

[0094] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A test method for a phased-array acoustic source measurement and control system, characterized in that: Includes the following steps: S1. Set the pulse width of the transmission signals of the phased-array sound source and the target center calibration sound source to ΔT, and the acquisition pulse width of the target sound field measurement hydrophone and the array calibration hydrophone to T. S2. Set the initial distance to the target as R; S3. Control the target center calibration sound source to emit sound signals; S4. Use the area array calibration hydrophones on the phased array to collect the target center calibration sound source signal, obtain the time delay of each area array calibration hydrophone, and locate the target center calibration sound source based on the time delay to obtain the target center calibration sound source position r. S5. Calculate the time delay ti of each phased sound source relative to the target center based on the target center calibration sound source position r, and then calculate the new time delay Δti. S6. Trigger phased-controlled transmission. Each phased-controlled sound source transmits sound signals according to the new time delay Δti. The system outputs the phased-controlled center time delay correction. S7. Based on the delay of the target sound field measurement hydrophone, the sound signal is received by the target sound field measurement hydrophone, and the sound intensity level at the center of the target is calculated. S8. Focused beamwidth measurement: When determining the target center r, the focusing center is successively offset by xi, and focusing is performed at the offset points. The sound intensity at different offset points is measured by the hydrophone in the target sound field to obtain the focused beamwidth curve and intensity diagram. S9. Phased array scanning: Given the location of the scanning center region, the focus point is shifted regularly at the center to complete the region scanning; S10. Track and focus: Based on the changes in the target points given in the implementation, focus on the target points and complete the tracking; S11. Read the maximum sound intensity of the receiving array. S12. Record the test results and determine whether the target requirements have been met.

2. An underwater focusing high-intensity acoustic system based on phase control, applied to the testing method of the phase-controlled acoustic source measurement and control system as described in claim 1, characterized in that: The system includes 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 center calibration sound source, a driver, a target sound field measurement hydrophone, and a measurement and control host computer. The 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 receives the emission signal and phased-array parameters from the host computer and generates a phase control signal to control the acoustic wave emission. The multi-channel power amplifier receives and amplifies the phase control signal from the phased-array signal generator to drive the acoustic emission phased array. The 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 sound waves. The array calibration hydrophones receive the reflected sound wave signals. The data acquisition unit converts the reflected sound wave signals received by the array calibration hydrophones into digital signals and sends them to the host computer. The target center calibration sound source is set at the center of the target to transmit signal pulse width. The driver is used to drive the target center 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 center 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.

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

4. The underwater focusing acoustic system based on phase control according to claim 2, characterized in that: The target acoustic field measurement hydrophone is either a scalar hydrophone or a vector hydrophone.

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