An unmanned survey vessel depth sensor coupling detection device

Abstract

The application discloses an unmanned surveying ship depth sensor coupling detection device, and belongs to the technical field of depth sensor detection of unmanned surveying ships.The device comprises a tubular shell, one side end plate of which is provided with an opening part; a sound-transmitting rubber is embedded in the opening part, and a SCS sensor is arranged on the end surface of the tubular shell, which extends out of the tubular shell; a composite sound-absorbing lining is arranged on the inner wall of the tubular shell, and is used for reducing the reflection of ultrasonic waves at the interface between water and the inner wall of the shell; a plurality of conical waveguides are arranged on the second end plate of the tubular shell, which is away from the bottom plate of the unmanned ship, and are used for scattering and attenuating ultrasonic reflection signals; a plurality of annular baffles are arranged along the central axis direction of the tubular shell at intervals, and the outer diameters of the annular baffles gradually decrease along the central axis direction of the tubular shell; the composite sound-absorbing lining can work cooperatively with the conical waveguides and the annular baffles, the reflected echo in the shell is scattered and attenuated for multiple times, the background noise and false echoes are reduced, and the detection result is more reliable.

Description

Technical Field

[0001] This invention belongs to the field of unmanned survey vessel depth sounder detection technology, and particularly relates to an unmanned survey vessel depth sounder coupling detection device. Background Technology

[0002] With the increasing demand for aquatic environment monitoring, waterway surveying, and flood prevention and early warning, unmanned surface vessels (USVs) are gradually becoming important tools for aquatic exploration due to their flexibility and automation advantages. Ultrasonic depth sounders are one of the core devices of unmanned survey vessels. They calculate water depth by emitting high-frequency sound waves and receiving reflected signals from the seabed, using the sound wave propagation time and the speed of sound in water.

[0003] In practical testing applications, the transducers of unmanned survey vessels are often installed on the bottom of the vessel using an embedded mounting method. The surface of the transducer is recessed into the bottom plate to form a mounting groove structure. For example, the Huawi 4 unmanned survey vessel fixes the transducer to a V-shaped mounting bracket, which directly engages with the mounting connecting rod on the lifting fin to control the transducer's water depth. It lowers the transducer when in use and raises it when not in use. However, when performing ultrasonic testing on the depth sounding sensors of unmanned survey vessels, the standard calibration sensor (SCS sensor) is typically used. This method, which involves direct coupling via a coupling agent or physical plane, is incompatible with the actual application scenarios of unmanned vessels. Furthermore, it presents the following technical problems: 1. Low coupling efficiency: Because the transducer of the unmanned vessel is recessed into the bottom plate, when using an external detection transducer for coupling, the ultrasonic signal is scattered in the air, resulting in significant energy loss and decreased detection accuracy; 2. Risk of sensor burnout: The recessed structure causes the ultrasonic signal to reflect and focus in the air, easily forming a high-intensity sound field locally, which can burn out the detection sensor; 3. Mismatched detection scenario: Existing detection devices cannot simulate the actual installation environment and operating conditions of the unmanned vessel transducer, making it difficult for the detection results to reflect the true performance.

[0004] Therefore, there is an urgent need to provide a coupling detection device for depth sounding sensors on unmanned survey vessels that can simulate the actual use scenario of unmanned vessel transducers, achieve efficient coupling between the sensor under test and the standard sensor, and quickly dissipate high-intensity ultrasonic signals. Summary of the Invention

[0005] In view of this, the present invention proposes an unmanned survey vessel depth sounder coupling detection device with a tubular structure, which can better couple with the unmanned vessel transducer, reduce the energy loss of sound waves at the coupling interface, and simulate the installation state and usage environment of the unmanned vessel transducer.

[0006] This invention provides a depth sounding sensor coupling detection device for an unmanned survey vessel, comprising: The tubular shell is hollow inside, and an opening is provided on the first end plate on the side of the tubular shell near the bottom plate of the unmanned vessel. Sound-permeable rubber is embedded in the opening and extends towards the inside and outside of the tubular shell, respectively. An SCS sensor is provided on the end face of the sound-permeable rubber extending out of the tubular shell. A composite sound-absorbing liner is provided on the inner wall of the tubular shell to reduce the reflection of ultrasonic waves at the interface between the water and the inner wall of the shell. Several conical waveguides are set on the second end plate on the side of the tubular shell away from the bottom plate of the unmanned vessel, for scattering and attenuating ultrasonic reflected signals; Several annular baffles are spaced apart along the central axis of the tubular shell to scatter and attenuate ultrasonic reflected signals.

[0007] Based on the above technical solutions, preferably, the height of the sound-permeable rubber extending from the opening is adapted to the depth of the mounting groove on the unmanned vessel's bottom plate, so that the SCS sensor is directly coupled to the unmanned vessel's bottom plate.

[0008] Based on the above technical solutions, preferably, the composite sound-absorbing liner includes a first sound-absorbing layer, a second sound-absorbing layer and a third sound-absorbing layer arranged in sequence. The first sound-absorbing layer is disposed on the inner wall of the tubular shell, the second sound-absorbing layer is disposed on the surface of the first sound-absorbing layer away from the tubular shell, and the third sound-absorbing layer is disposed on the surface of the second sound-absorbing layer away from the tubular shell. By gradient impedance matching, the energy after ultrasonic wave reflection is reduced.

[0009] Preferably, the first sound-absorbing layer is made of special rubber with a thickness of 10 mm, used to absorb reverse radiation energy; the second sound-absorbing layer is a polyurethane foam layer with a porous structure and a thickness of 10 mm, which uses the porous structure to allow ultrasonic waves to be reflected multiple times in the pores to consume energy; the third sound-absorbing layer is a rubber-epoxy resin mixture layer with a thickness of 5 mm, used to reduce the energy reflected back into the tubular shell.

[0010] Based on the above technical solutions, preferably, one end of a plurality of tapered waveguides is disposed on the inner surface of the second end plate, and the other end extends along the central axis of the tubular shell. The cross-sectional area of ​​the plurality of tapered waveguides gradually shrinks along the first preset direction of the tubular shell, wherein the first preset direction is the direction of the central axis of the tubular shell pointing towards the opening.

[0011] Preferably, several conical waveguides are made of high-density polyethylene or polytetrafluoroethylene.

[0012] Preferably, the annular baffles have the same inner diameter and thickness, and the outer diameter of the annular baffles decreases sequentially along a first preset direction.

[0013] Preferably, the outer diameters of the three consecutive annular baffles arranged sequentially along the first preset direction are distributed in an arithmetic sequence, and all are larger than the outer diameter of the annular baffle at the end near the opening.

[0014] Preferably, the spacing between adjacent annular baffles is adjustable.

[0015] Based on the above technical solutions, preferably, the system also includes a water circulation pipeline and a bubble generator. The water circulation pipeline is used to connect to the inlet and outlet on the tubular shell and to fill the tubular shell with liquid. The bubble generator is installed on the tubular shell and is used to fill the tubular shell with bubbles to improve the absorption capacity of high-frequency ultrasound through Rayleigh scattering.

[0016] The present invention provides a depth sounding sensor coupling detection device for an unmanned survey vessel, which has the following advantages compared with the prior art: 1. By configuring acoustically transparent rubber and SCS sensors on the tubular shell, the actual installation state and usage environment of the unmanned vessel transducer can be simulated. The acoustically transparent rubber can significantly reduce the reflection and energy loss of sound waves at the coupling interface, and improve the sound energy transmission efficiency. The composite sound-absorbing liner can effectively suppress the reflection of ultrasonic waves between the water and the shell. It can also work in conjunction with the conical waveguide and the annular baffle to scatter and attenuate the reflected echoes inside the shell multiple times, greatly reducing the background noise and false echoes, making the detection results more reliable and more valuable for engineering reference.

[0017] 2. The size of the sound-permeable rubber protruding from the opening is matched with the depth of the mounting groove on the bottom plate of the unmanned vessel, which can avoid secondary interface reflection caused by gaps, more realistically simulate the sensor's onboard state, and improve the coupling result.

[0018] 3. The composite sound-absorbing lining adopts a three-layer gradient impedance matching design, which gradually transitions the acoustic impedance, thereby reducing interlayer reflection and achieving efficient absorption of ultrasonic energy.

[0019] 4. The variable cross-section contraction structure of the conical waveguide converts the reflected wave into a divergent wave, which can effectively reduce the echo intensity. The high-density polyethylene or polytetrafluoroethylene material is selected, which has the characteristics of corrosion resistance and high strength, and is suitable for long-term use in aquatic environments.

[0020] 5. Multiple annular baffles form a progressively narrowing acoustic channel, forcing ultrasonic waves to scatter continuously during their passage, significantly increasing propagation path loss. In addition, the spacing between adjacent annular baffles can be appropriately adjusted according to the detection requirements of transducers with different frequencies and power, improving the adaptability and scalability of the device.

[0021] 6. By configuring water circulation pipes and bubble generators on the shell, the hydrological environment inside the shell is maintained to be close to that of the actual water area. On the other hand, bubbles can be generated to enhance the absorption of high-frequency ultrasonic waves through Rayleigh scattering mechanism, thereby further suppressing high-frequency noise. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a half-section front view of a depth sounding sensor coupling detection device for an unmanned survey vessel according to the present invention; Figure 2 This is a top view of a depth sounding sensor coupling detection device for an unmanned survey vessel according to the present invention.

[0024] Reference numerals: 1. Tubular shell; 2. Vent hole; 3. Composite sound-absorbing lining; 31. First sound-absorbing layer; 32. Second sound-absorbing layer; 33. Third sound-absorbing layer; 4. Bubble generator; 5. SCS sensor; 6. Sound-permeable rubber; 7. Conical waveguide; 8. Water inlet; 9. Annular baffle; 10. Water outlet. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] When performing ultrasonic testing on the depth sounding sensors of unmanned survey vessels, SCS sensors are typically used, with direct coupling via a coupling agent or physical plane. However, this method is not suitable for the actual application scenarios of unmanned vessels and also presents the following technical problems: 1. Low coupling efficiency: Because the transducer of the unmanned vessel is recessed into the bottom plate plane, when using an external detection transducer for coupling, the ultrasonic signal is scattered in the air, resulting in significant energy loss and a decrease in detection accuracy; 2. Risk of sensor burn-out: The recessed structure causes the ultrasonic signal to reflect and focus in the air, easily forming a high-intensity sound field in a localized area, which can burn out the detection sensor; 3. Mismatched detection scenario: Existing detection devices cannot simulate the actual installation environment and working conditions of the unmanned vessel transducer, and the detection results are difficult to reflect the true performance.

[0027] In view of this, such as Figure 1, Figure 2 As shown, the present invention provides a depth sounding sensor coupling detection device for an unmanned survey vessel, comprising: The tubular housing 1 is hollow inside, and an opening is provided on the first end plate on the side of the tubular housing 1 closest to the bottom plate of the unmanned vessel; this first end plate is used to support the SCS sensor. The internal space of the tubular housing 1 is used to fill with water to simulate the operating environment of the SCS sensor.

[0028] In one embodiment, the tubular shell 1 is a cylindrical tubular structure with an inner diameter of 20cm, a length of 100cm, and a wall thickness of 2cm. The tubular shell 1 is made of stainless steel, and the inner wall is treated with anti-corrosion coating.

[0029] A sound-permeable rubber 6 is embedded in the opening and extends both inside and outside the tubular housing 1. An SCS sensor 5 is mounted on the end face of the sound-permeable rubber 6 extending out of the tubular housing 1. The sound-permeable rubber 6 has an acoustic impedance similar to that of water, enabling efficient acoustic coupling between the detection sensor and the unmanned vessel transducer, reducing ultrasonic wave reflection loss at the interface. Simultaneously, the sound-permeable rubber 6 provides fixation and protection for the detection sensor, preventing mechanical vibration and external interference.

[0030] In one embodiment, the height of the acoustically transparent rubber 6 extending from the opening is adapted to the depth of the mounting groove on the unmanned surface vessel's (USV) bottom plate, allowing the SCS sensor 5 to be directly coupled to the USV bottom plate. The USV bottom plate has a mounting groove whose dimensions are adapted to the cross-sectional dimensions of the acoustically transparent rubber 6, and whose depth is adapted to the height of the protrusion of the acoustically transparent rubber 6. This ensures efficient acoustic coupling between the SCS sensor 5 and the transducer on the USV, eliminating the need for additional coupling agent and bridging the height difference between the USV bottom surface and the end face of the SCS sensor 5, reducing sound wave reflection loss at the interface. The depth of the mounting groove is typically 5-10 mm. The coupled signal from the SCS sensor 5 can quickly propagate into the tubular housing 1, with some ultrasonic signals absorbed by the sound-absorbing structure designed inside the tubular housing 1.

[0031] The composite sound-absorbing liner 3 is set on the inner wall of the tubular shell 1 to reduce the reflection of ultrasonic waves at the interface between the water and the inner wall of the shell. The composite sound-absorbing liner 3 has a multi-layer sound-absorbing structure, which realizes gradient impedance matching, effectively reduces the reflection of ultrasonic waves at the interface between the water and the pipe wall, and allows most of the sound energy to be absorbed layer by layer.

[0032] In one embodiment, the composite sound-absorbing liner 3 includes a first sound-absorbing layer 31, a second sound-absorbing layer 32, and a third sound-absorbing layer 33 arranged sequentially from the outside to the inside. The first sound-absorbing layer 31 is disposed close to the inner wall of the tubular shell 1, the second sound-absorbing layer 32 is disposed on the surface of the first sound-absorbing layer 31 away from the tubular shell 1, and the third sound-absorbing layer 33 is disposed on the surface of the second sound-absorbing layer 32 away from the tubular shell 1. By gradient impedance matching, the energy after ultrasonic wave reflection is reduced. The first sound-absorbing layer 31 is made of special rubber, preferably tungsten-impedanced rubber, with a thickness of 10 mm. The acoustic impedance of this tungsten-impedanced rubber composite is higher than that of water, effectively absorbing sound waves incident from the water onto the inner wall of the tubular shell 1, preventing ultrasonic waves from radiating to the external environment through the pipe wall. The second sound-absorbing layer 32 is a polyurethane foam layer with a porous structure and a thickness of 10 mm. This porous structure allows ultrasonic waves to be reflected multiple times within the pores, consuming energy and increasing the length of the sound wave transmission path, gradually converting sound energy into heat energy. The third sound-absorbing layer 33 is a rubber-epoxy resin mixture layer. Its acoustic impedance is close to that of water, and its thickness is 5 mm. As the innermost layer, it directly contacts the water, reducing the reflection of sound waves from the water to the composite sound-absorbing liner 3, achieving a gradient transition of acoustic impedance. Through the synergistic effect of these three layers, the absorption amount through the composite sound-absorbing liner 3 in a single pass reaches 10-20 dB.

[0033] Several conical waveguides 7 are disposed on the second end plate on the side of the tubular shell 1 away from the bottom plate of the unmanned vessel, for scattering and attenuating ultrasonic wave reflection signals; the conical waveguides 7 disperse and reflect axially propagating ultrasonic waves onto the surface of the composite sound-absorbing liner 3 or the annular baffle, preventing ultrasonic waves from being directly reflected back to the SCS sensor 5 at the second end plate. One end of the several conical waveguides 7 is disposed on the inner surface of the second end plate, and the other end extends along the central axis of the tubular shell 1. The cross-sectional area of ​​the several conical waveguides 7 gradually decreases along a first preset direction of the tubular shell 1, which is the direction of the central axis of the tubular shell 1 pointing towards the opening.

[0034] In this embodiment, several conical waveguides 7 are made of high-density polyethylene or polytetrafluoroethylene. The contour of the conical waveguide 7 is conical, and the cone angle α of the conical waveguide 7 is in the range of 30°-45°, preferably 40°. The bottom radius and height of the conical waveguide 7 satisfy tanα=R / h, where R is the bottom radius and h is the height of the conical waveguide 7. The structure of the conical waveguide 7 is used to realize diffuse reflection of sound waves, which is beneficial to converting reflected waves into divergent waves and effectively reducing the echo intensity inside the tubular shell 1.

[0035] In a preferred embodiment, the height of the conical waveguide 7 is 119.18 mm and the bottom diameter is 100 mm.

[0036] Several annular baffles 9 are spaced apart along the central axis of the tubular shell 1 to scatter and attenuate ultrasonic reflected signals. The annular baffles 9 enable ultrasonic waves to be reflected multiple times between the baffles. Each reflection has a portion of the energy absorbed by the composite sound-absorbing lining 3 on the inner wall of the tubular shell 1. Through multiple reflections and attenuation, the total attenuation reaches 15-25dB, effectively preventing high-intensity ultrasonic signal reflections from burning out the SCS sensor 5.

[0037] The device comprises at least four annular baffles 9, each with the same inner diameter and thickness. The outer end faces of several annular baffles 9 are fixedly connected to the inner wall of the tubular housing 1, and the inner diameters of the annular baffles 9 decrease sequentially along a first preset direction. In one embodiment, the inner diameters of the three annular baffles 9 closest to the second end plate are distributed in an arithmetic sequence, and the outer diameters of these three annular baffles 9 are all larger than the outer diameter of the annular baffle 9 closest to the opening. Typically, the spacing between adjacent annular baffles 9 can be set to a fixed value; however, to improve the applicability of the detection device, the spacing between adjacent annular baffles 9 can be adjusted.

[0038] In this embodiment, there are four annular baffles 9, each with the same inner diameter and mounted on the same vertical connecting rod. Each annular baffle 9 has a thickness of 2mm. The four annular baffles 9, arranged from bottom to top along a first preset direction, are designated as the first annular baffle, the second annular baffle, the third annular baffle, and the fourth annular baffle. The outer diameters of the first, second, and third annular baffles are 160mm, 120mm, and 80mm, respectively, while the outer diameter of the fourth annular baffle is 50mm.

[0039] If the spacing between adjacent annular baffles 9 is not adjustable, the spacing can be fixed at 180mm. If the spacing between adjacent annular baffles 9 is adjustable, the spacing can be adjusted between 120-200mm to adapt to the testing requirements of sensors with different frequencies. The annular baffles 9 are made of stainless steel. To facilitate the adjustment of the spacing between the annular baffles 9, axial grooves and positioning holes can be opened on the vertical connecting rod. The annular baffles 9 can be moved through the axial grooves, and their current position on the vertical connecting rod can be limited by the positioning holes and fasteners.

[0040] In one embodiment, the detection device further includes a water circulation pipeline and a bubble generator 4. The water circulation pipeline is connected to the inlet 8 and outlet 10 on the tubular housing 1 to fill the tubular housing 1 with liquid. The bubble generator 4 is inserted through the tubular housing 1 to fill the tubular housing 1 with bubbles and improve the absorption capacity of high-frequency ultrasound through Rayleigh scattering.

[0041] An inlet 8 and an outlet 2 are provided on the first end plate. Bubble generators 4 and outlets 10 are located at different positions on the side wall of the tubular housing 1. When the tubular housing 1 simulates the operating environment of the SCS sensor 5, a water circulation pipeline is connected through the inlet 8 and outlet 10 to fill the tubular housing 1 with water as the sound transmission medium. The bubble generator 4 can generate bubbles inside the tubular housing 1 to simulate the working state of the unmanned measurement vessel in a bubble environment. The outlet 2 is used to discharge the bubbles in the water. If the unmanned measurement vessel under test has good bubble anti-interference capabilities, the bubble generator 4 can be turned on to improve the absorption of high-frequency sound waves through Rayleigh scattering, further enhancing the simulation capability of the free sound field.

[0042] In one embodiment, a method for using the depth sounder coupling detection device of the unmanned survey vessel of the present invention is provided, specifically including the following steps: Step 1: Install SCS sensor 5, and use sound-permeable rubber 6 to make the transmitting / receiving unit tightly coupled with the sound-permeable rubber 6, and embed SCS sensor 5 into the mounting groove of the bottom plate of the unmanned measurement vessel; Step 2: Water injection and defoaming. Fill the tubular shell 1 with water, start the bubble generator 4 and open the defoaming hole to simulate the working state of the unmanned boat in a still water environment. Step 3: Coupling and detection. The transducer of the depth sounding sensor is placed close to the outside of the bottom plate of the unmanned measuring vessel. The SCS sensor 5 emits an ultrasonic signal, which is coupled through the acoustic rubber 6 and penetrates the bottom plate of the unmanned measuring vessel to form an acoustic link with the transducer of the unmanned measuring vessel. Step 4: Signal attenuation. During the detection process, the high-intensity ultrasonic signal propagates inside the tubular shell 1. After being absorbed by the composite sound-absorbing liner 3, dispersed and reflected by the conical waveguide 7, and reflected multiple times by the annular baffle 9, the sound energy is quickly exhausted to avoid being reflected back to the detection sensor and causing it to burn out. Step 5: Data acquisition and analysis. The SCS sensor 5 receives the echo signal from the unmanned vessel transducer and analyzes the sensor's performance parameters, including sensitivity, resolution, and anti-interference capability, through the signal processing module.

[0043] Comparative Verification: To verify the technical effect of this invention, a comparative test was conducted using a conventional water-filled bladder storage device without an internal attenuation structure. The detection sensor was directly exposed to the air and coupled to the transducer of the unmanned measurement vessel. The test conditions were: detection sensor operating frequency 200kHz, power 50W. The results showed that using the detection device of this invention, the sound pressure level attenuation at a distance of 80cm from the SCS sensor reached 36dB, with the output sound pressure attenuated to 0.25% of its original value. The detection sensor operated stably without the risk of burnout. In contrast, the ultrasonic signal of the comparative example was scattered in the air, resulting in uneven energy loss. The detection sensor burned out due to localized high-intensity sound field reflections, making detection impossible. It is evident that the technical solution of this invention achieves efficient coupling while effectively protecting the detection sensor, demonstrating significant technological advancement.

[0044] The following are the performance simulation results of the depth sounding sensor coupling detection device of the unmanned measuring vessel of this application. Let the axial depth be equal to the tube length of the tubular shell 1. Using SOMSOL simulation software, the acoustic impedance, attenuation coefficient and geometric dimensions of the material provided in this application are directly modeled. The pressure acoustics-frequency domain module is selected, and the frequency sweep is 50kHz / 200kHz. The medium injected into the tubular shell 1 is clean water. The total attenuation obtained is shown in Table 1.

[0045] Table 1 In the table, I0 represents the original sound intensity, and I represents the sound intensity at the current structural location. Based on the table data, the relationship between total attenuation and axial depth x is: ΔL(x) = (0.2 + k)x, where k is the equivalent attenuation coefficient, k = 44.8 dB / m.

[0046] Introducing bubble generator 4 will add an additional scattering attenuation term α. bubble The relationship between the total attenuation and the axial depth x is then modified to: ΔL(x) = (0.2 + k + α) / ( ... bubble x, scattering attenuation term α bubble The value range is 5-20 dB / m.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coupling detection device for a depth sounding sensor on an unmanned survey vessel, characterized in that, include: The tubular shell is hollow inside, and an opening is provided on the first end plate on the side of the tubular shell near the bottom plate of the unmanned vessel. Sound-permeable rubber is embedded in the opening and extends towards the inside and outside of the tubular shell, respectively. An SCS sensor is provided on the end face of the sound-permeable rubber extending out of the tubular shell. A composite sound-absorbing liner is provided on the inner wall of the tubular shell to reduce the reflection of ultrasonic waves at the interface between the water and the inner wall of the shell. Several conical waveguides are set on the second end plate on the side of the tubular shell away from the bottom plate of the unmanned vessel, for scattering and attenuating ultrasonic reflected signals; Several annular baffles are spaced apart along the central axis of the tubular shell to scatter and attenuate ultrasonic reflected signals.

2. The unmanned survey vessel depth sounder coupling detection device according to claim 1, characterized in that, The height of the sound-permeable rubber extending from the opening is adapted to the depth of the mounting groove on the unmanned vessel's bottom plate, allowing the SCS sensor to be directly coupled to the unmanned vessel's bottom plate.

3. The unmanned survey vessel depth sounder coupling detection device according to claim 1, characterized in that, The composite sound-absorbing liner includes a first sound-absorbing layer, a second sound-absorbing layer, and a third sound-absorbing layer arranged in sequence. The first sound-absorbing layer is disposed on the inner wall of the tubular shell, the second sound-absorbing layer is disposed on the surface of the first sound-absorbing layer away from the tubular shell, and the third sound-absorbing layer is disposed on the surface of the second sound-absorbing layer away from the tubular shell. By using gradient impedance matching, the energy of ultrasonic waves after reflection is reduced.

4. The unmanned survey vessel depth sounder coupling detection device according to claim 3, characterized in that, The first sound-absorbing layer is made of special rubber with a thickness of 10mm, used to absorb reverse radiation energy; the second sound-absorbing layer is a polyurethane foam layer with a porous structure and a thickness of 10mm, which uses the porous structure to allow ultrasonic waves to be reflected multiple times in the pores to consume energy; the third sound-absorbing layer is a rubber-epoxy resin mixture layer with a thickness of 5mm, used to reduce the energy reflected back into the tubular shell.

5. The unmanned survey vessel depth sounder coupling detection device according to claim 1, characterized in that, One end of several tapered waveguides is disposed on the inner surface of the second end plate, and the other end extends along the central axis of the tubular shell. The cross-sectional area of ​​the tapered waveguides gradually shrinks along the first preset direction of the tubular shell, which is the direction of the central axis of the tubular shell pointing towards the opening.

6. The unmanned survey vessel depth sounder coupling detection device according to claim 5, characterized in that, Several conical waveguides are made of high-density polyethylene or polytetrafluoroethylene.

7. The unmanned survey vessel depth sounder coupling detection device according to claim 5, characterized in that, Several annular baffles have the same inner diameter and thickness, and the outer diameter of several annular baffles decreases sequentially along a first preset direction.

8. The unmanned survey vessel depth sounder coupling detection device according to claim 7, characterized in that, The outer diameters of three consecutive annular baffles arranged in sequence along the first preset direction are distributed in an arithmetic sequence, and all of them are larger than the outer diameter of the annular baffle near the end of the opening.

9. The unmanned survey vessel depth sounder coupling detection device according to claim 7, characterized in that, The spacing between adjacent annular baffles is adjustable.

10. The unmanned survey vessel depth sounder coupling detection device according to claim 1, characterized in that, It also includes a water circulation pipeline and a bubble generator. The water circulation pipeline is used to connect to the inlet and outlet on the tubular shell to fill the tubular shell with liquid. The bubble generator is installed on the tubular shell to fill the tubular shell with bubbles, which improve the absorption of high-frequency ultrasound through Rayleigh scattering.

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