Laser interferometry based calibration apparatus and method for a vibrating liquid column hydrophone

Abstract

The application relates to the technical field of mechanical vibration or ultrasonic, underwater acoustic wave or infrasonic wave measurement, in particular to a laser interference measurement-based vibration liquid column hydrophone calibration device and method, which comprises a laser vibration tester, a to-be-measured hydrophone, a liquid column cavity suspending the to-be-measured hydrophone, and a vibration table connected with the liquid column cavity; the to-be-measured hydrophone is detachably connected with an adjusting and positioning mechanism; the adjusting and positioning mechanism is connected with the laser vibration tester for performing vibration measurement; the application introduces the adjusting and positioning mechanism and the laser vibration tester, solves the problem that accurate calibration of a low-frequency hydrophone cannot be realized in the prior art, and solves the technical problem that the uncertainty and deviation of the sensitivity calibration result of the hydrophone caused by a non-uniform sound field cannot be effectively reduced in the prior art through sound field modeling calculation and correction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical vibration or ultrasonic, underwater acoustic wave or infrasonic wave measurement, in particular to a vibration liquid column hydrophone calibration device based on laser interferometry, and a calibration method. BACKGROUND

[0002] A hydrophone is the most basic and commonly used sensor for picking up and measuring underwater acoustic signals, and its sensitivity needs to be calibrated regularly to ensure the accuracy of the measured underwater acoustic signal values, and is widely used in underwater target detection, positioning and navigation, ocean noise measurement and other fields. The vibration liquid column method is an important and commonly used method for low-frequency calibration of hydrophones. The hydrophone is suspended in a liquid column cavity driven by a vibration table in a sine wave, the vibration acceleration is measured by an acceleration sensor (accelerometer), and the sensitivity of the hydrophone at different frequency points is calculated according to the transmission line theory using parameters such as vibration frequency, underwater sound speed, cavity size, and hydrophone depth. The calibration is completed. However, in the existing vibration liquid column method for hydrophone calibration, the sensitivity of the acceleration sensor is calibrated by laser method or comparison method, which introduces a larger measurement uncertainty component, and long-term measurement may cause the acceleration sensor and the liquid column cavity to become loose, affecting the measurement results. On the other hand, when calibrating a large-sized hydrophone in the liquid column cavity, the hydrophone itself will affect the sound field distribution in the liquid column cavity, especially when the calibration frequency is increased, the sound wave wavelength does not meet the requirement of being much larger than the size of the cavity or the size of the hydrophone, which will cause the sound field acting on the sensitive element of the hydrophone to be non-uniform, resulting in a significant deviation in the calibration results and affecting the improvement of the measurement uncertainty level.

[0003] In the prior art, a Chinese patent with publication date of November 26, 2021 and publication number CN214893653U, entitled "Low-frequency hydrophone calibration device based on vibration liquid column method", discloses a four-square vertical support, a vertical connector is fixed to the side surface of the upper end of the four-square vertical support, a cross-shaped connector is arranged above the four-square vertical support, and the cross-shaped connector is provided with a cross-shaped jack, the cross-shaped connector is provided with three, the vertical connector is provided with a vertical jack, and the vertical connector and the cross-shaped connector are arranged between the vertical connector and the cross-shaped connector. The four-square vertical support can stably fix the hydrophone to be measured, so that the hydrophone always remains vertical and downward, and the position of the hydrophone can be adjusted and controlled. The height can be accurately adjusted according to the scale of the hollow pipe wall, and the cross connector can be locked after adjustment to start the next experiment. The device is convenient and easy to operate, the vibration cavity has good airtightness, is easy to fix with the vibration table, is convenient to install, and has stable vibration. The device adopts a three-section design, which greatly facilitates the installation of the accelerometer.

[0004] The calibration results of the foregoing technical solution need to be improved, and the uncertainty and deviation of the hydrophone sensitivity calibration results caused by the non-uniform sound field cannot be effectively reduced. SUMMARY

[0005] The inventors have found that, as a new technology for vibration and acoustic measurement, laser interferometry can realize non-contact measurement, and has higher measurement accuracy and resolution than traditional acceleration sensors, especially when measuring small amplitude vibrations, and can realize accurate measurement of nanoscale displacement changes, while acceleration sensors may be limited by their own noise and sensitivity when measuring such small vibrations, especially, acceleration sensors are generally calibrated by laser interferometry, and the transmission path is long and the measurement uncertainty is large when measuring the acceleration information of the vibrating liquid column cavity using an acceleration sensor.

[0006] The purpose of the present application is to provide a vibrating liquid column hydrophone calibration device and method based on laser interferometry, specifically a vibrating liquid column low-frequency hydrophone calibration device and method based on laser interferometry, which introduces an adjusting and positioning mechanism and a laser vibration meter based on the existing disclosed calibration device to solve the problem that the existing technology cannot realize accurate calibration of low-frequency hydrophones; on the other hand, through sound field modeling calculation and correction, the technical problem of the existing technology that cannot effectively reduce the uncertainty and deviation of the hydrophone sensitivity calibration result caused by non-uniform sound field is solved.

[0007] According to one aspect of the present application, a vibrating liquid column hydrophone calibration device based on laser interferometry is provided, comprising a to-be-measured hydrophone, a liquid column cavity suspending the to-be-measured hydrophone, and a vibration table connected with the liquid column cavity, the to-be-measured hydrophone is detachably connected with an adjusting and positioning mechanism, and the adjusting and positioning mechanism is connected with a laser vibration meter for performing vibration measurement.

[0008] In some embodiments, the laser vibration meter is connected with a vibration velocity signal demodulator.

[0009] In some embodiments, the vibration velocity signal demodulator is connected with an oscilloscope through a channel,

[0010] In some embodiments, the to-be-measured hydrophone is connected with a preamplifier.

[0011] In some embodiments, the preamplifier is connected with an oscilloscope through a channel.

[0012] In some embodiments, the oscilloscope is connected with an upper computer.

[0013] In some embodiments, the upper computer is connected with a signal source.

[0014] In some embodiments, the signal source is connected with a power amplifier.

[0015] In some embodiments, the power amplifier is connected with the vibration table.

[0016] According to another aspect of the present application, a laser interferometry-based calibration method for a vibrating liquid column hydrophone is provided, comprising:

[0017] determining the size parameters of the target liquid column cavity (2) and removing air bubbles in the liquid in the target liquid column cavity (2);

[0018] installing the target hydrophone (3);

[0019] performing gain calibration on the preamplifier (7) to set the signal parameters and the power amplifier gain;

[0020] measuring the vibration velocity u(f) of the target liquid column cavity (2) by the laser vibrometer (4);

[0021] calculating the surface sound pressure p h (f) of the target hydrophone (3) in the target liquid column cavity (2);

[0022] correcting the sound pressure Δp h (f) by simulation modeling;

[0023] measuring the open-circuit voltage U H (f) of the target hydrophone (3);

[0024] calculating the sensitivity M H (f) of the target hydrophone (3);

[0025] determining whether the calibration needs to be continued, if yes, the host computer (10) program controls automatic change of the signal frequency f; if no, the calibration is ended.

[0026] Compared with the prior art, the present application uses a laser vibrometer to replace a conventional acceleration sensor, directly and non-contactly measures the vibration velocity of the liquid column cavity, avoids possible connection looseness, shortens the transmission path of the hydrophone sensitivity value, and improves the calibration level of a low-frequency hydrophone; meanwhile, the present application obtains correction values of the influence of hydrophones of different frequencies and different sizes on the sound field distribution through sound field modeling and simulation calculation, improves the accuracy of the calibration result, and improves the application range of the entire device to the hydrophone. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 is a schematic diagram of the calibration device of the present application;

[0029] Figure 2 is a schematic diagram of the calibration device of the present application;

[0030] Figure 3 It is a flow chart of the calibration method of this application.

[0031] Legend:

[0032] 1-vibration table; 2-liquid column chamber; 3-hydrophone to be tested; 4-laser vibrometer; 5-adjustment and positioning mechanism; 6-vibration velocity signal demodulator; 7-preamplifier; 8-power amplifier; 9-oscilloscope; 10-host computer; 11-signal source; In order to avoid interference with technical features, Figure 1 Some guide lines in the figure are dotted. DETAILED DESCRIPTION

[0033] The following is a combination of the appended examples of the present application Figures 1-3 The technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0034] Explanation of some terms in this application:

[0035] Channel 1: CH1;

[0036] Channel 2: CH2.

[0037] Application Overview

[0038] Existing vibrating liquid column hydrophone calibration systems use accelerometers to measure the acceleration values ​​of the vibration table 1 and the cavity. However, the performance of the accelerometer itself relies on mechanical sensing elements, resulting in low measurement accuracy. To obtain the accelerometer sensitivity value, the accelerometer must first be calibrated using the reciprocity method or laser interferometry. The uncertainty introduced by calibration exceeds 0.2dB, which in turn causes the combined uncertainty of the hydrophone calibration to exceed 0.6dB, increasing the traceability path of the hydrophone sensitivity value. In addition, when measuring higher-frequency vibrations, the accelerometer is limited by its sensitive material and structure, and its frequency response range is limited. Finally, the accelerometer requires physical contact with the object being measured (liquid column cavity 2). Factors such as the fixing method and position during installation may affect the measurement results and add a lot of uncertainty. For example, if the accelerometer follows the vibration of the liquid column cavity 2 for a long time, the connection may become loose, affecting the acceleration measurement and hydrophone calibration results.

[0039] Meanwhile, when the size of the to-be-tested hydrophone 3 is large, the hydrophone itself will affect the sound field pressure distribution in the liquid column cavity, especially when the calibration frequency is increased, the sound wave wavelength does not satisfy the condition of being much larger than the size of the cavity or the size of the hydrophone, which will cause the sound field acting on the sensitive element of the hydrophone to be non-uniform, resulting in obvious deviation of the calibration result, and the measurement uncertainty will also be significantly increased. The existing scheme does not consider this situation, resulting in that the vibration liquid column method hydrophone calibration system is only applicable to hydrophones with small size and negligible influence on the sound field, and the application range is limited. Alternatively, the size of the cavity can be increased to adapt to the calibration of large-size hydrophones, but at the same time, the upper limit of the working frequency of the vibration liquid column method hydrophone calibration system will also be reduced.

[0040] Embodiment 1

[0041] The embodiment provides a vibration liquid column hydrophone calibration device based on laser interference measurement, which comprises a to-be-tested hydrophone 3, a liquid column cavity 2 suspending the to-be-tested hydrophone, and a vibration table 1 connected with the liquid column cavity, the to-be-tested hydrophone 3 is detachably connected with an adjusting and positioning mechanism 5, and the adjusting and positioning mechanism 5 is connected with a laser vibration tester 4 for performing vibration measurement.

[0042] It should be noted that the adjusting and positioning mechanism 5 and the laser vibration tester 4 are arranged in the embodiment, the adjusting and positioning mechanism 5 is provided to realize detachable connection of the laser vibration tester 4, the adjusting and positioning mechanism 5 can be adjusted in time according to the actual use condition, and the device can be conveniently disassembled, installed, repaired and maintained, so that the convenience in the use process of the whole device is improved. The acceleration sensor used in the prior art may be loosened after long-time vibration, and the sensitivity of the acceleration sensor needs to be calibrated every time it is used, which is not only troublesome to operate, but also prone to looseness and errors, and finally affects the measurement error of the whole device. In the embodiment, the laser vibration tester 4 is arranged, the laser interference measurement technology of the laser vibration tester 4 is directly introduced into the low-frequency hydrophone calibration for vibration measurement, compared with the acceleration sensor used in the prior art, the laser vibration tester 4 used in the embodiment can not only be more direct when calculating the sound pressure in the calculation cavity, but also can save the calibration link of the sensitivity of the acceleration sensor, thereby effectively eliminating the measurement uncertainty introduced by the calibration of the acceleration sensor, shortening the value transmission chain, realizing the effect of further reducing the measurement uncertainty of the existing calibration device, reducing the measurement error of the whole calibration device, improving the accuracy of the measurement result, and further improving the calibration level of the whole vibration liquid column method low-frequency hydrophone.

[0043] In detail, the vibration liquid column hydrophone calibration device provided by the embodiment measures the vibration velocity of the liquid column cavity 2 by the laser interference method of the laser vibration tester 4, then calculates the sound pressure value of the receiving surface of the hydrophone through the relationship between the vibration velocity and the sound pressure, and finally measures the output voltage of the hydrophone by using the preamplifier 7 and the oscilloscope 9.

[0044] It should be noted that when designing the liquid column cavity 2, a rust-proof metal material with acoustic stiffness is preferred, and the size thereof should satisfy: the inner diameter 2r of the cavity is much smaller than the wavelength of the acoustic wave in water corresponding to the highest working frequency, the height L of the liquid column formed in the cavity during testing should be greater than the inner diameter 2r of the cavity, and the total mass of the cavity and the liquid column should not exceed the maximum load of the vibration table 1, so as to prevent signal distortion; the height L of the liquid column should also be less than 1 / 4 of the wavelength of the acoustic wave in water corresponding to the measured (highest) frequency, so as to avoid liquid column resonance. The upper end of the cavity should be polished to allow the laser to be well reflected, and preferably, a reflective material can be attached to the laser measurement area on the upper surface of the cavity.

[0045] Further, the laser vibration measuring instrument 4 is signal-connected with a vibration speed signal demodulator 6. The laser interference signal is converted into a vibration speed signal through the connected vibration speed signal demodulator 6.

[0046] In some embodiments, the vibration speed signal demodulator is connected with an oscilloscope 9 through a channel. The preamplifier 7 is connected with the oscilloscope 9 through a channel. The set oscilloscope 9 is used to convert the invisible electrical signal into a visible image.

[0047] Further, the to-be-measured hydrophone is signal-connected with a preamplifier 7. The gain-calibrated preamplifier 7 is connected to measure the voltage output by the hydrophone in combination with the oscilloscope 9.

[0048] Further, the oscilloscope data are connected with an upper computer 10. The connected upper computer 10 directly issues control commands, which can be a PC or a host computer or a master computer or an upper computer, and has a display screen on which various signal changes such as sound pressure, voltage, temperature, etc. are displayed.

[0049] Further, the upper computer is signal-connected with a signal source 11. The signal source 11 is signal-connected with a power amplifier 8. The power amplifier 8 is signal-connected with the vibration table 1. The connected signal source 11 and power amplifier 8 are used to drive the vibration table 1 to drive the liquid column cavity 2 and the internal liquid to make a sinusoidal motion in the vertical direction at a certain set frequency.

[0050] Embodiment 2

[0051] In order to better understand the present application, the present embodiment provides an exemplary method, which is described with reference to Figure 3 A vibration liquid column hydrophone calibration method based on laser interference measurement, comprising:

[0052] Determining the size parameters of the target liquid column cavity (2) and removing the gas bubbles in the liquid in the target liquid column cavity (2);

[0053] Installing the target hydrophone (3);

[0054] The gain calibration is performed on the preamplifier (7), and the signal parameters and power amplifier gain are set;

[0055] The laser vibrometer (4) measures the vibration velocity u(f) of the target liquid column cavity (2);

[0056] The surface sound pressure p of the target hydrophone (3) in the target liquid column cavity (2) is calculated h (f);

[0057] The simulation modeling correction sound pressure Δp h (f);

[0058] The open circuit voltage U of the target hydrophone (3) is measured H (f);

[0059] The sensitivity M of the target hydrophone (3) is calculated H (f);

[0060] It is judged whether the calibration needs to be continued, if yes, the program of the host computer (10) controls the automatic change of the signal frequency f; if not, the calibration is ended.

[0061] It should be noted that for the hydrophone with large sensitive element size, in the case that it is difficult to obtain the accurate analytical expression of the sound field after the hydrophone is immersed in the liquid, the sound field simulation analysis model is established based on the vibration liquid column low frequency hydrophone calibration device provided in the embodiment, the load (cavity size and liquid column height) suitable for the vibration table 1 is determined through numerical simulation, the influence of the hydrophone with different sizes on the sound field distribution under different frequencies is calculated, and the hydrophone sensitivity correction factor is given, which effectively reduces the uncertainty and deviation of the calibration result of the hydrophone sensitivity caused by the non-uniform sound field, improves the accuracy of the low frequency hydrophone calibration, and can reduce the uncertainty from 0.6dB to within 0.4dB.

[0062] In detail, before the calibration starts, deaerated water is added to the target liquid column cavity 2, and the target hydrophone 3 is suspended and fixed in the target liquid column cavity 2, coinciding with the center axis of the liquid column, and the target hydrophone 3 and its cable are completely isolated from the vibration table and the liquid column cavity without direct coupling; preferably, the acoustic center of the target hydrophone 3 is placed at the center height of the liquid column. The height h of the acoustic center of the target hydrophone 3 from the liquid surface, the height L of the cavity bottom to the liquid surface are accurately measured, and the gain calibration of the preamplifier 7 at the output end of the target hydrophone 3 is performed to obtain the actual gain value at different frequencies. It is also necessary to check whether the signal source 11 excitation signal amplitude and the power amplifier 8 gain are appropriate, and the specific method is: in the actual working state, respectively move the target hydrophone 3 into and out of the liquid column, measure the signal-to-noise ratio of the open circuit voltage of the target hydrophone 3, the value should be not less than 30dB, and the output waveform of the target hydrophone 3 in the whole working frequency range has no obvious distortion.

[0063] Further, during calibration, the signal source is set to emit a sinusoidal signal with frequency f, which is used to drive the vibration table 1 to vibrate via the power amplifier 8, wherein the amplitude of the sinusoidal signal and the gain of the power amplifier 8 are set to satisfy the above conditions. Since the liquid column height L is greater than the inner diameter 2r of the cavity, the sound wave in the cavity can be regarded as a plane wave only; and the sound pressure at the interface between the liquid column and the air is 0. According to the sound propagation theory and the boundary conditions, the sound pressure at the depth h can be calculated as:

[0064]

[0065] where p L represents the sound pressure at the depth L (i.e. the bottom of the liquid column cavity 2), is the wave number, ω = 2πf is the angular frequency of vibration, and c is the sound speed in the liquid. The sound pressure at the bottom of the liquid column cavity 2 and the vibration velocity u(f) satisfy the following relationship:

[0066] p L (f) = ρcu(f) tan(kL)

[0067] where ρ is the density of the liquid. By combining the above two equations, the sound pressure at the depth h of the hydrophone can be obtained as:

[0068]

[0069] In the above equation, except for the vibration velocity u(f), all other quantities are known. The vibration velocity of the cavity can be directly measured by using the laser interferometer 4, and the vibration velocity signal is demodulated to obtain.

[0070] Further, the preamplifier 7 and the oscilloscope 9 are used to measure the open-circuit voltage U H (f) of the hydrophone when the hydrophone is placed in the liquid column cavity 5, and the sound pressure sensitivity of the hydrophone is obtained as:

[0071]

[0072] From the above process, it can be known that, compared with the traditional method of using an acceleration sensor, the measurement uncertainty introduced by the laser interferometer is smaller due to the higher precision of directly measuring the vibration velocity, which can improve the overall uncertainty level of the calibration device.

[0073] Further, the above hydrophone sensitivity calculation process does not consider the influence of the hydrophone immersed in the liquid column cavity 2 on the sound field pressure distribution, especially when the size of the hydrophone is larger than the wavelength of the sound wave. According to the vibration velocity and frequency of the liquid column cavity 2, the size (inner diameter and height) of the liquid column cavity 2, the density and sound speed of the liquid, the liquid column height, the size of the hydrophone, and the depth of the hydrophone acoustic center into the water, etc., the sound field distribution model in the cavity is established by using the sound field modeling and simulation software, and the average sound pressure acting on the sensitive element surface of the hydrophone at the vibration frequency f is obtained by simulation calculation: The surface sound pressure of the hydrophone calculated by the above formula is p h (f), then the sound pressure correction value of the hydrophone of a certain model or size when calibrated in the vibrating liquid column cavity 2 is:

[0074]

[0075] Further, considering the influence of the hydrophone on the sound field distribution, the actual sound pressure sensitivity of the hydrophone after correction is

[0076]

[0077] In the case where the accurate analytical formula of the sound field after the hydrophone is immersed in the liquid cannot be obtained, a sound field simulation analysis model is established based on the developed vibrating liquid column calibration device, the influence of the hydrophone of different sizes on the sound field distribution at different frequencies is obtained through numerical calculation, and a hydrophone sensitivity correction factor is given, which can effectively reduce the calibration uncertainty and deviation of the sensitivity of a large-size hydrophone caused by a non-uniform sound field, improve the absolute calibration level of the hydrophone in the frequency range of 10Hz-2kHz, and better guarantee the performance and role of the hydrophone in the application of ocean exploration, noise measurement, resource exploration, etc.

[0078] It should be noted that the vibrating liquid column hydrophone calibration method provided in the embodiment obtains the correction value of the influence of hydrophones of different sizes on the sound field distribution at different frequencies through sound field modeling and simulation calculation, improves the accuracy of the calibration result, and is more widely applicable to hydrophones.

[0079] It should be noted that the vibrating liquid column hydrophone calibration method provided in the embodiment calculates the sensitivity of the to-be-measured hydrophone 3, taking a common piezoelectric hydrophone as an example, by calculating the sound pressure sensitivity of the hydrophone through the output open-circuit voltage of the hydrophone, but as long as the measurement frequency is in the range of 10Hz-2kHz, the method is also applicable to fiber-optic hydrophones, vector hydrophones, etc., and only the output open-circuit voltage needs to be changed to output phase shift (for fiber-optic hydrophones), output vibration velocity or acceleration (for vector hydrophones), so that the phase shift sensitivity of the fiber-optic hydrophone, the vibration velocity sensitivity or acceleration sensitivity of the vector hydrophone can be calibrated.

[0080] The foregoing merely illustrates the principles of the application and application of its leading features. This application is not limited to the specific embodiments described herein. In addition, any combination of claims reciting "comprising" are intended to mean that the claimed subject matter includes at least the recited elements, but not excluding others. Any combination of claims reciting "consisting of are intended to mean that the claimed subject matter includes exactly the recited elements. Any combination of claims reciting "consisting essentially of are intended to mean that the claimed subject matter includes the recited elements, plus any additional optional elements that do not materially affect the basic and novel characteristics of the claimed subject matter. Any reference in this specification to something being "invented" or "created" is intended to mean that the claimed subject matter was not known before the claimed invention, and is not obvious to one of ordinary skill in the art at the time of the claimed invention.

[0081] Furthermore, it should be understood that although the description above relates to embodiments, it is not intended to limit the scope of the application to the particular embodiments described in this specification. Rather, the description itself is deemed to form prior art as regards this application, and its scope of protection is defined by the appended claims. It is therefore intended that any variations be deemed to fall within the scope of the application.

Claims

1. A vibrating liquid column hydrophone calibration device based on laser interferometry, comprising a hydrophone to be measured (3), a liquid column cavity (2) for suspending the hydrophone to be measured (3), and a vibration table (1) connected to the liquid column cavity (2), characterized in that: The hydrophone to be tested (3) is detachably connected to an adjustment and positioning mechanism (5), the adjustment and positioning mechanism (5) is connected to a laser vibrometer (4) for measuring the vibration velocity of the liquid column cavity (2), the laser vibrometer (4) is signal-connected to a vibration velocity signal demodulator (6), the vibration velocity signal demodulator (6) is connected to an oscilloscope (9) via channel 2, the hydrophone to be tested (3) is signal-connected to a preamplifier (7), and the preamplifier (7) is connected to the oscilloscope (9) via channel 1; The size of the liquid column cavity (2) satisfies the following requirements: the cavity diameter 2r is much smaller than the wavelength of the acoustic wave in water corresponding to the highest operating frequency; the height L of the liquid column formed in the cavity during testing is greater than the cavity diameter 2r; and the liquid column height L is less than 1 / 4 of the wavelength of the acoustic wave in water corresponding to the highest frequency measured; The adjustment and positioning mechanism (5) is used to adjust the hydrophone (3) to be tested so that it is suspended and fixed in the liquid column cavity (2) and coincides with the central axis of the liquid column; The calibration device is suitable for low-frequency calibration of hydrophones in the range of 10 Hz to 2 kHz.

2. The calibration device according to claim 1, characterized in that The oscilloscope (9) is data-connected to a host computer (10).

3. The calibration device according to claim 2, characterized in that The host computer (10) is signal-connected to a signal source (11).

4. The calibration device according to claim 3, characterized in that The signal source (11) is signal-connected to a power amplifier (8).

5. The calibration device according to claim 4, characterized in that The power amplifier (8) is signal-connected to the vibration table (1).

6. A method for calibrating a vibrating liquid column hydrophone based on laser interferometry, characterized in that: The method uses the calibration device according to any one of claims 1 to 5, and the calibration method includes: Determining the size parameters of the target liquid column cavity (2) and removing bubbles in the liquid in the target liquid column cavity (2); Installing the hydrophone to be tested (3); Performing gain calibration on the preamplifier (7) to set signal parameters and power amplifier gain; The laser vibrometer (4) measures the vibration velocity u(f) of the target liquid column cavity (2); Calculate the surface sound pressure p of the hydrophone (3) to be tested in the target liquid column cavity (2) h (f); Simulation modeling to correct sound pressure Δp h (f); Represents the average sound pressure acting on the surface of the hydrophone sensitive element when the vibration frequency is f; Measure the output open circuit voltage U of the hydrophone (3) to be tested H (f); Calculate the sensitivity M of the hydrophone (3) to be tested H (f); Where h is the height from the acoustic center of the hydrophone to the liquid surface, L is the height from the bottom of the cavity to the liquid surface, ρ is the liquid density, and c is the speed of sound in the liquid. is the wave number, ω=2πf is the vibration angular frequency; It is determined whether calibration needs to be continued. If so, the host computer (10) program controls to automatically change the signal frequency f; if not, the calibration ends.

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