Underwater focusing strong sound system and method based on phase control

Abstract

The invention discloses an underwater focusing intense sound system and method based on phase control, and relates to the technical field of focusing intense sound, and the technical scheme is characterized in that a measurement and control upper computer is used for controlling the emission and detection of a trigger signal; 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. By generating the high-energy strong-focusing sound field and combining the actual underwater signal propagation process, accurate positioning and control of the underwater strong sound field can be completed, so that accurate focusing irradiation and high-resolution imaging of a long-distance small target are realized.

Description

Technical Field

[0001] The present invention relates to the field of focused strong sound technology, and more specifically, to an underwater focused strong sound system and method based on phase control. Background Art

[0002] In imaging detection, the irradiated sound source is not only required to have a large emission sound power, but also a large emission angle, which is technically difficult to meet at the same time; increasing the emission power requires increasing the sound source volume, 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 illumination uses increasing the sound source emission power as the main method to obtain the scattered signal of the small target to achieve the detection purpose; however, due to the small emission angle, the irradiated target is out of focus, and the sound propagation loss is large due to the long distance, so the echo signal of the small target is often unable to be obtained.

[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. This way, the sound waves excited by each sound source have a certain phase difference when propagating in the medium, so that the phases reaching the target node are consistent 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 referred to as 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 at the same time. One of the main purposes of using a phased sound source is to generate 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, it propagates farther in the medium, and it has stronger scattering against small obstacles.

[0004] The application of phased array concept in the radar field is relatively mature, and the high-intensity phased array technology has also made great progress. However, in the field of underwater acoustics, due to the complex transmission environment and differences in propagation principles, the phased array method has higher requirements on the condition setting and data processing methods of the imaging system. There is still a large gap from mature application in terms of method design and actual performance.

[0005] Therefore, the present invention aims to provide an underwater focused strong sound system and method based on phase control to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide an underwater focused strong sound system and method based on phase control. By combining the actual underwater signal propagation process, the present invention can complete the precise positioning and control of the underwater strong sound field, thereby achieving the focusing enhancement effect of the sound waves and realizing the precise focused irradiation and high-resolution imaging of small targets at a long distance.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: an underwater focused strong sound system and method based on phase control, including 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 to set measurement and control parameters, control the emission and detection trigger signals, and record and display the results; the phased signal generator is used to receive the emission of the measurement and control host computer. The multi-channel power amplifier receives the phase control signal of the phase-controlled signal generator and amplifies it to drive the acoustic emission phased array, and the power supply provides power to the multi-channel power amplifier; the acoustic emission phased array receives the phase control signal forwarded by the multi-channel power amplifier to emit sound waves; the array calibration hydrophone is used to receive the signal of the reflected sound wave; the data acquisition unit converts the signal of the reflected sound wave 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 arranged at the center of the target for transmitting a signal pulse width, the driver is used to drive the target calibration sound source to operate, the target sound field measurement hydrophone is arranged at the center of the target for receiving the signal pulse width emitted by the target calibration sound source and forwarding it to the measurement and control host computer, and 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 as follows: the array calibration hydrophones are arranged in four numbers for collecting the pulse width of the emission signal of the acoustic emission phased array.

[0010] The present invention is further configured such that: the target sound field measurement hydrophone adopts a scalar hydrophone or a vector hydrophone.

[0011] The present invention also provides an underwater focused strong sound method based on phase control, comprising the following steps:

[0012] S1, the main control station receives and processes data from the inertial navigation and GPS, and generates serial port commands;

[0013] S2, the total trigger unit receives the serial port command of the total control host computer, 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 the sound waves, and the sound detection collection unit collects and sends the data to the data storage;

[0016] S5, the phased array sound source controls the host computer to process data, calculate the phased delay parameters, and control the phased array sound source signal generator;

[0017] S6, a phased sound source signal generator generates and transmits a phased array sound signal;

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

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

[0020] In summary, the present invention has the following beneficial effects:

[0021] 1. The present invention provides an underwater focusing system and method based on phase control, which can flexibly control the focus point to achieve multi-level and multi-depth focusing on a small target surface. In practical applications, it can achieve strong acoustic focusing of more than 210 dB, solving the problem that various types of attenuation will occur in the underwater propagation process of the sound waves emitted by the current acoustic array, avoiding the diffusion attenuation caused by the sound beam diffusion phenomenon, the scattering attenuation caused by the acoustic impedance of the cross section of different media, and the absorption attenuation caused by the viscosity between particles inside the medium, which will weaken the energy of the acoustic signal, resulting in a decrease in the sensitivity of the received echo detection and a deterioration in the imaging resolution.

[0022] 2. The present invention uses a designed phase-controlled delay algorithm to realize regular transmission of multiple sound sources by using a hardware programming language, and generates pulse signals with different phases and the same frequency. On the basis of low power supply voltage, strong transmission signal of a single transducer and good consistency between sound source channels, it can achieve precise delay control with an error within 25ns, and the minimum resolution of the phase-controlled delay signal can reach 10ps, which lays a good foundation for achieving high-quality underwater imaging and coping with complex underwater environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the principle of phased focusing strong sound in an embodiment of the present invention;

[0024] Figure 2 is a flow chart of a phase-controlled sound source measurement and control system according to an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the time delay setting of the phase-controlled sound source measurement and control system in an embodiment of the present invention;

[0026] Figure 4 It is a schematic diagram and a real-shot image of a T-type structure phased sound source measurement and control system in an embodiment of the present invention;

[0027] Figure 5 Schematic diagram of the overall operation of the phase-controlled sound source measurement and control system in an embodiment of the present invention;

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

[0029] Figure 7 Schematic diagram of the working process of the phase-controlled sound source measurement and control system in an embodiment of the present invention;

[0030] Figure 8 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] Fig. 9 is a schematic diagram of the minimum resolution of the phase-controlled delay signal in an embodiment of the present invention;

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

[0033] Fig.11 is a schematic diagram of a waveform and amplitude of a channel linear frequency modulation sound signal received in an embodiment of the present invention;

[0034] Fig.12 1 is a schematic diagram of a total of 18-channel linear frequency modulation sound signal receiving waveforms in an embodiment of the present invention;

[0035] Fig.13 Schematic diagram of pulse compression results of 18-channel linear frequency modulation sound signals in an embodiment of the present invention;

[0036] Fig.14 is a schematic diagram of a single-channel acoustic signal pulse compression result in an embodiment of the present invention;

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

[0038] Fig.16 It is the standard listening sensitivity measurement data and curve diagram in the embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following is combined with Figure 1-16 The present invention is described in further detail.

[0040] Embodiment 1: An underwater focused strong sound system based on phase control, comprising a phase-controlled 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 emission and detection trigger signals, and record and display the results; the phase-controlled signal generator is used to receive the emission signal and phase control parameters of the measurement and control host computer, and generate a phase control signal for controlling the emission of sound waves; the multi-channel power amplifier receives the phase control signal of the phase-controlled signal generator and amplifies it to drive the acoustic emission phased array, and the power supply provides electrical energy for the multi-channel power amplifier; the acoustic emission phased array receives the phase control signal forwarded by the multi-channel power amplifier for emitting sound waves; the four array calibration hydrophones are used to receive the signal of the reflected sound wave and collect the pulse width of the emission signal of the acoustic emission phased array; the data acquisition unit converts the signal of the reflected sound wave received by the array calibration hydrophone into a digital signal and sends it to the measurement and control host computer;

[0041] The target calibration sound source is set at the center of the target to transmit the 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 emitted by the target calibration sound source and forward it to the measurement and control host computer, and 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] Embodiment 2: An underwater focused strong sound method based on phase control, comprising the following steps:

[0043] Data synchronization: The master control station receives and processes data from the inertial navigation system and GPS, and generates serial port commands;

[0044] Signal triggering: The main trigger unit receives the serial port command from the main control host computer to trigger the sound source signal generator and the positioning hydrophone data receiving module;

[0045] Signal amplification and transmission: The sound source signal generator generates a sound signal, which is amplified by a single sound source 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 acquisition unit collects and sends data to the data storage;

[0047] Data processing and control: The phased array sound source controls the host computer to process data, calculate the phased delay parameters, and control 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 collects data of phased array acoustic signals and sends them to the data storage device;

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

[0051] Example 3: Test experiment of phase-controlled sound source measurement and control system

[0052] Phased array sound source is a phase-compensated (or time-delay-compensated) acoustic emission array. Its working principle is to appropriately shift the phase (or delay) of the signals of the acoustic emission transducer array elements arranged in a certain pattern to obtain the deflection of the array beam, thereby achieving precise positioning and control of the sound field. The precise beam formation of the phased array sound source enables a larger sound source level in the specified space; the phased array sound source can also scan and track the beam within the desired spatial range through precise phase and time delay control, such as Figure 1 As shown, the origin of the phased array coordinates is at the center of the array, the number of phased acoustic emission units (fixed in the system) is N, and the coordinates of each phased acoustic emission unit are: {Xi, Yi} N. The calibration sound source S0 and the phased acoustic field measurement hydrophone D0 are installed at the target center.

[0053] In this embodiment, an underwater focused strong sound system based on phase control in Embodiment 1 is used as a phase-controlled sound source measurement and control system for testing. The working principle of the phase-controlled sound source measurement and control system is as follows: Figure 2 As shown in Figure 2, the time delay setting of the phase-controlled sound source measurement and control system is as follows: Figure 3 As shown in the figure, the schematic diagram and real-shot image of the T-type structure phased sound source measurement and control system are as follows: Figure 4 As shown in the figure, the overall working diagram of the phase-controlled sound source measurement and control system is as follows Figure 5 shown.

[0054] In this embodiment, according to Figure 6 Connect the test system, connect the digital signal source output to the trigger input of the super-resolution phased array sound source signal generator, and output a DC pulse signal with a pulse width of 2%, a signal period of 1Hz, a high level of 5V, and a low level of 0V.

[0055] The analog command terminal is connected to the super-resolution phased array sound source signal generator through a gigabit network cable. The acoustic emission digital signal is written through the analog command terminal host software. The signal frequencies are 70K, 75K, 80K, 85K, 90K, 95K, 100K, 105K, 110K, 115K and 120KHz, respectively. The signal length is 2ms and the amplitude is 1.7V. The acoustic emission digital signals are transmitted in sequence through the host software. The frequency and amplitude of the acoustic signal received by the standard hydrophone are observed and measured by an oscilloscope. When the frequency of the signal received by the standard hydrophone is consistent with the transmitted signal, the sound source level calculation formula is as follows:

[0056] M 0 =20*lgV 0 -M s +20*lgS

[0057] The sound source level: M 0 ; The signal amplitude received by the standard hydrophone: V 0 ; Standard hydrophone sensitivity: M s ; Standard hydrophone and transducer distance: S.

[0058] In this embodiment, the scenario is built at the test site according to the above test conditions. After the debugging equipment can operate normally, the test implementation steps are entered, which are as follows:

[0059] 1) The pulse width of the transmitted signal of the phase-controlled sound source and the target center calibration sound source is: △T = 1ms, and the pulse width of the phase-controlled sound field measurement hydrophone D0 and the 4 positioning hydrophones D1~4 is: T = 20ms;

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

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

[0062] 4) The 4 positioning hydrophones on the phased array collect signals with a delay of td = R / V-10ms (generated by the system), and obtain the delays of each hydrophone td1-4, and locate the calibration sound source r;

[0063] 5) According to the calibration sound source position r, calculate the time delay ti of each phased sound source to the target center, and calculate the new time delay △ti = ti (Max) - ti;

[0064] 6) Phased-control emission: When the trigger arrives, each phase-controlled sound source emits according to the time delay △ti, and the system outputs the phase-controlled center delay correction ti (Max);

[0065] 7) The phased acoustic field is measured by measuring the hydrophone D0 delay t0 = r / v-10ms to obtain the target center sound intensity level, and the target center sound intensity level is calculated based on the received signal;

[0066] 8) Focused beam width measurement: When measuring the target center r, the focus center is offset xi in turn, and the focus is focused according to the offset point. The sound intensity at the target center hydrophone D0 and the sound intensity at -xi are measured. Multi-point measurements are performed to obtain the focused beam intensity curve (one-dimensional offset) or intensity diagram (two-dimensional offset), and the focused beam width is calculated from this.

[0067] 9) Phased scanning: Given the scanning center area position, regular focus point offset is made at this center to complete the regional scanning;

[0068] 10) Tracking and focusing: According to the implementation, the target point is changed, and the tracking is completed by focusing on the target point;

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

[0070] 12) Record the test results and determine whether the index requirements are met.

[0071] The working order of each device in the phase-controlled sound source measurement and control system of this embodiment is as follows: Figure 7 shown.

[0072] Experimental data

[0073] This embodiment conducts on-site inspection. The total number of system control transmitting units is 72 (actually 20 units can meet the target, 18 units are phase-controlled, and 2 units are positioned). The sound source level test is as follows: Figure 8 As shown, the delay time resolution is Fig. 9 As shown, channel delay control accuracy test: select any three phase-controlled sound waveform signal outputs, set the three-way delay to 1*1 / 48M, 2*1 / 48M, and 3*1 / 48M respectively, the test results are as follows Fig.10 As shown, it can be seen that the curves are consistent and the accuracy is high.

[0074] In the measurement and correction of the initial phase of the phase-controlled sound source, each phase-controlled sound source is emitted according to the time delay △ti+5ms×i, and the phase-controlled measurement hydrophone D0 determines the actual time delay ti of each phase-controlled sound source signal, dti=ti-5ms×i, that is, the initial phase and correction of the phase-controlled sound source. The result is as follows: Figure 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 parameters Distance delay parameters 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 the phased sound source focusing, the measured initial phase error of the phased sound source is corrected to the phase control parameters. The phased focusing results of 18-way linear FM signal are as follows: Fig.15 shown.

[0078] The single channel output signal of the sound source array, the standard listening receiving signal amplitude is: 0.32 ~ 0.33Vpp, the sensitivity measurement data and curve are as follows Fig.16 shown.

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

[0080] Table 2 Delay parameter group 1 and focused sound intensity results

[0081]

[0082] Table 3 Delay parameter group 2 and focused sound intensity results

[0083]

[0084]

[0085] Table 4 Delay parameter group 3 and focused sound intensity results

[0086]

[0087]

[0088] Table 5 Delay parameter group 4 and focused sound intensity results

[0089]

[0090] Table 6 Delay parameter group 5 and focused sound intensity results

[0091]

[0092]

[0093] Conclusion: By adjusting the phase of the signal sent by each sound source of the phased array sound source, the receiving array receives the accurate focused signal, and the sound intensity value is tested. It can be clearly seen that the signal strength is enhanced, and the focused sound intensity is greater than 210dB.

[0094] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An underwater focused strong sound system based on phase control, characterized by: It includes 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 to set measurement and control parameters, control emission and detection trigger signals, and record and display the results; the phased signal generator is used to receive the emission signal and phase control parameters of the measurement and control host computer, and generate a phase control signal for controlling the emission of sound waves; the multi-channel power amplifier receives the phase control signal of the phased signal generator and amplifies it to drive the acoustic emission phased array, and the power supply provides electrical energy for the multi-channel power amplifier; the acoustic emission phased array receives the phase control signal forwarded by the multi-channel power amplifier for emitting sound waves; the array calibration hydrophone is used to receive the signal of the reflected sound wave; the data acquisition unit converts the signal of the reflected sound wave received by the array calibration hydrophone into a digital signal and sends it to the measurement and control host computer; The target calibration sound source is arranged at the center of the target for transmitting a signal pulse width, the driver is used to drive the target calibration sound source to operate, the target sound field measurement hydrophone is arranged at the center of the target for receiving the signal pulse width emitted by the target calibration sound source and forwarding it to the measurement and control host computer, and the measurement and control host computer receives the signal pulse width forwarded by the target sound field measurement hydrophone for system evaluation and correction.

2. The underwater focused strong sound system based on phase control according to claim 1 is characterized by: The array calibration hydrophones are arranged in four numbers and are used to collect the pulse width of the emission signal of the acoustic emission phased array.

3. The underwater focused strong sound system based on phase control according to claim 1 is characterized by: The target sound field measurement hydrophone adopts a scalar hydrophone or a vector hydrophone.

4. An underwater focused strong sound method based on phase control, characterized by: The following steps are involved: S1, the main control station receives and processes data from the inertial navigation and GPS, and generates serial port commands; S2, the total trigger unit receives the serial port command of the total control host computer, triggers the sound source signal generator and the positioning hydrophone data receiving module; 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; S4, the hydrophone array receives the sound waves, and the sound detection collection unit collects and sends the data to the data storage; S5, the phased array sound source controls the host computer to process data, calculate the phased delay parameters, and control the phased array sound source signal generator; S6, a phased sound source signal generator generates and transmits a phased array sound signal; S7, the acoustic detection acquisition unit collects data of the phased array acoustic signal and sends it to the data storage; S8. Repeat steps S1-S7 to continue detecting.

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