Underwater acoustic beacon and use method thereof

Abstract

The present invention proposes an underwater acoustic beacon and a method for using the same, which relates to the field of underwater vehicle communication technology. The beacon comprises a shell, an acoustic cavity is provided inside the shell, an excitation port is provided on the front side wall of the shell facing the direction of movement, the excitation port is used to connect the acoustic cavity with the outside of the shell, and the excitation port can generate underwater acoustic waves in the acoustic cavity under the action of water flow, a plurality of acoustic holes are provided on the surface of the shell, the acoustic holes are used to connect the acoustic cavity with the outside of the shell, and an adjustment device for adjusting the size of the acoustic hole opening is provided on the acoustic hole. The present invention uses water flow to excite the acoustic cavity to generate acoustic waves. The excitation of the acoustic waves is passive and does not rely on electrical energy, which reduces the demand for electrical energy and thus reduces power consumption. By using water flow to directly act on the acoustic cavity to generate acoustic waves, the step of converting electrical energy is bypassed, the energy loss in the conversion process is reduced, and the overall efficiency of acoustic wave generation is improved.

Description

Technical Field

[0001] The present invention relates to the field of underwater vehicle communication technology, and in particular to an underwater acoustic beacon and a use method thereof. Background Art

[0002] In the operation of a swarm of intelligent underwater unmanned vehicles, mutual recognition and positional awareness between adjacent vehicles are crucial for achieving collaborative work. This mutual recognition helps vehicles determine their own and the overall mission's execution status, allowing them to make necessary adjustments to mission planning, thereby improving overall mission efficiency. Furthermore, the ability to identify other vehicles outside the swarm is essential to avoid potential unexpected situations.

[0003] Currently, underwater unmanned vehicles (UAVs) often identify and locate surrounding vehicles by continuously transmitting sound waves of a specific frequency. This function primarily relies on acoustic beacons or active sonar systems. Traditional implementations include using transducers with piezoelectric or electromagnetic technologies to convert electrical energy into vibrational energy in the water, which in turn emits sound waves. However, this approach has the following disadvantages: 1. High power consumption, especially over long distances, where power consumption can reach hundreds of kilowatts; 2. Low conversion efficiency from electrical energy to acoustic energy, resulting in limited transmission distance at low power consumption. Equipment costs are high and require the vehicle's active sonar resources. Summary of the Invention

[0004] In view of this, the present invention proposes an underwater acoustic beacon and a method of use to solve the problems of high power consumption and low conversion efficiency of electrical energy to acoustic energy in the prior art acoustic beacon by converting electrical energy into acoustic energy.

[0005] The technical solution of the present invention is achieved as follows:

[0006] In a first aspect, the present invention provides an underwater acoustic beacon, comprising a shell, wherein the shell has an acoustic cavity inside, an excitation port is provided on the front side wall of the shell facing the direction of movement, the excitation port is used to connect the acoustic cavity with the outside of the shell, and the excitation port can generate underwater acoustic waves into the acoustic cavity under the action of water flow, a plurality of sound holes are provided on the surface of the shell, the sound holes are used to connect the acoustic cavity with the outside of the shell, and an adjustment device for adjusting the size of the sound hole opening is provided on the sound hole.

[0007] On the basis of the above technical solution, preferably, the front side wall of the shell facing the movement direction is also provided with a water inlet pipe connected to the excitation port, the water inlet pipe is an arc-shaped structure, the open end of the water inlet pipe is parallel to the axial direction of the shell, the inner diameter of the water inlet pipe gradually increases from the end close to the excitation port to the end away from the excitation port, and the opening of the end of the water inlet pipe close to the excitation port is in the shape of a slit.

[0008] On the basis of the above technical solution, preferably, the upper surface of the shell is provided with a plurality of sound holes, and the inner diameters of the plurality of sound holes remain the same or gradually decrease from the end close to the excitation port to the end away from the excitation port; the lower surface of the shell is also provided with a plurality of sound holes, and the inner diameters of the plurality of sound holes remain the same or gradually increase from the end close to the excitation port to the end away from the excitation port.

[0009] Further, preferably, the sound hole includes an adjustment cavity and a sound transmission port, the sound transmission port is located on the outer wall of the shell, the adjustment cavity is located on the inner wall of the shell and is connected with the sound transmission port and the sound cavity, the inner diameter of the adjustment cavity is larger than the inner diameter of the sound transmission port, the adjustment device is located on the outer wall of the shell, and includes an adjustment door and a first servo, the first servo is used to drive the adjustment door to rotate to adjust the opening size of the sound transmission port, and the first servo is electrically connected to the control unit of underwater navigation.

[0010] On the basis of the above technical solution, preferably, the inner diameter of the sound transmission port is 1 mm to 30 mm, and the inner diameter of the adjustment cavity is 1.5 to 5 times the inner diameter of the sound transmission port.

[0011] On the basis of the above technical solution, preferably, the shell is further provided with a resonance port connected to the sound cavity, the resonance port is located on the bottom surface of the shell away from the excitation port, and the outer surface of the shell is provided with a resonance membrane covering the resonance port.

[0012] Furthermore, preferably, the resonance film is made of an organic polymer material, a composite material, or an inorganic material.

[0013] On the basis of the above technical solution, preferably, a cover and a second servo are provided at the end of the water inlet pipe away from the excitation port, and the second servo is used to drive the cover to rotate to open or close the inlet of the water inlet pipe, and the second servo is electrically connected to the control unit of underwater navigation.

[0014] The front side of the shell facing the direction of movement is fixedly provided with a traction interface for connecting to the aircraft in a towing manner. The lower surface of the front side of the shell facing the direction of movement is fixedly provided with a counterweight, and the tail end of the shell is fixedly provided with a stabilizing belt.

[0015] In a second aspect, the present invention discloses a method for using an underwater acoustic beacon, which utilizes the underwater acoustic beacon described in the first aspect and includes the following steps:

[0016] S1. Installing an underwater acoustic beacon on an underwater vehicle, and keeping the acoustic cavity filled with water, and driving the underwater acoustic beacon in the water;

[0017] S2. When the underwater acoustic beacon moves forward, water flows through the water inlet pipe and impacts the excitation port, generating underwater acoustic waves and structural resonance in the acoustic cavity of the shell. By adjusting the opening and closing state of the acoustic hole, passive generation of specific underwater frequencies is achieved;

[0018] S3. When the sound wave frequency of the underwater acoustic beacon needs to be increased, the acoustic holes on the upper surface of the shell are gradually opened from the end of the shell away from the excitation port toward the excitation port, and then the acoustic holes on the lower surface of the shell are gradually opened from the end of the shell close to the excitation port toward the direction away from the excitation port;

[0019] S4. When it is necessary to reduce the sound wave frequency of the underwater acoustic beacon, the sound holes on the lower surface of the shell are gradually closed from the end of the shell away from the excitation port toward the excitation port, and then the sound holes on the upper surface of the shell are gradually closed from the end of the shell close to the excitation port toward the direction away from the excitation port.

[0020] The present invention has the following beneficial effects compared to the prior art:

[0021] (1) The present invention utilizes water flow to excite an acoustic cavity to generate sound waves. The excitation of the sound waves is passive and does not rely on electrical energy, which reduces the demand for electrical energy and thus reduces power consumption. By utilizing water flow to directly act on the acoustic cavity to generate sound waves, the step of electrical energy conversion is bypassed, energy loss during the conversion process is reduced, and the overall efficiency of sound wave generation is improved. In addition, the acoustic beacon structure of the present invention is simpler, does not require complex electrical energy conversion equipment, reduces manufacturing and maintenance costs, and improves the endurance of the system, making the acoustic beacon more economical and durable in underwater applications.

[0022] (2) The inner diameter of the water inlet pipe gradually increases from the end close to the excitation port to the end away from the excitation port. This structural setting can accelerate the water flow, reduce energy loss through the gradual expansion effect generated by the pipe, and make the water flow more effectively impact the excitation port. At the same time, the gradually increasing inner diameter setting can maximize the use of the kinetic energy of the water flow, so that less water flow energy can produce a stronger sound wave signal, enhancing the resonance effect in the sound cavity; the opening at the end of the water inlet pipe close to the excitation port is slit-shaped. This structural setting can converge the water flow into a high-speed water column, which acts more concentratedly on the excitation port, thereby improving the efficiency of the water flow excitation of the sound cavity and the intensity of the sound wave. (3) The configuration of the gradually increasing sound holes on the upper surface and the gradually increasing sound holes on the lower surface can accurately control the release and wavelength adjustment of the sound wave, and can effectively adjust the resonant frequency of the sound cavity. This structural setting allows the sound cavity to exhibit different resonance characteristics at different frequencies, which helps to achieve precise control of specific sound wave requirements.

[0023] (4) By coordinating the adjustment cavity, the sound transmission port, and the adjustment device, the acoustic characteristics of the acoustic beacon can be precisely adjusted in an underwater environment. The rotation of the adjustment door can finely control the opening of the sound transmission port, thereby precisely controlling the propagation path, wavelength, and resonant frequency of the sound wave. This design can adapt to different working environments, ensuring that the acoustic beacon can operate effectively under various underwater conditions and improving its working performance and adaptability in complex underwater environments.

[0024] (5) The combination of the resonant port and the resonant membrane helps to enhance the sound waves of a specific frequency in the acoustic cavity, improving the detection and recognition capabilities of the acoustic beacon. The setting of the resonant port can effectively guide the sound waves through the resonant membrane and optimize the propagation effect of the sound waves.

[0025] (6) A counterweight is fixedly provided on the lower front surface of the shell in the direction of movement. The counterweight helps to lower the center of gravity of the acoustic beacon and increase its stability when moving in the water. This can reduce the possibility of the acoustic beacon flipping or tilting during the towing process, ensuring that it maintains a predetermined posture and direction underwater. A stabilizing belt is fixedly provided at the tail end of the shell. The stabilizing belt can improve the stability of the acoustic beacon when moving underwater and prevent it from deflecting or becoming unstable under the action of water flow or towing force. This design ensures the precise positioning and effective operation of the acoustic beacon during underwater missions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a planar schematic diagram of a structural mode of the underwater acoustic beacon disclosed in the present invention;

[0028] Figure 2 A top view of an underwater acoustic beacon disclosed in the present invention;

[0029] Figure 3 This is a bottom view of the underwater acoustic beacon disclosed in the present invention;

[0030] Figure 4 This is a plan view of another structural mode of the underwater acoustic beacon disclosed in the present invention;

[0031] Figure 5 This is a schematic diagram of the underwater acoustic beacon disclosed in the present invention being installed on an underwater vehicle;

[0032] Reference numerals

[0033] 1. Shell; 10. Acoustic cavity; 11. Excitation port; 12. Acoustic hole; 2. Adjustment device; 3. Water inlet pipe; 121. Adjustment cavity; 122. Sound transmission port; 21. Adjustment door; 22. First servo; 13. Resonance port; 14. Resonance membrane; 15. Cover; 16. Second servo; 17. Towing interface; 18. Counterweight; 19. Stabilization belt; 4. Cabin. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, combined Figure 2-3 The present invention discloses an underwater acoustic beacon comprising a housing 1 and an acoustic cavity 10 therein. Acoustic cavity 10 communicates with the outside world via an excitation port 11. Housing 1 provides a physical space for the generation and propagation of sound waves. Acoustic cavity 10 exists to generate and amplify sound waves. The design of acoustic cavity 10 can control the propagation characteristics of the sound waves.

[0036] In this embodiment, the housing 1 adopts a wing-shaped design, which can effectively guide the water flow and reduce resistance, thereby enhancing the resonance effect. The shape of the housing 1 allows the pressure and kinetic energy generated by the water flow to be effectively utilized.

[0037] The design of the excitation port 11 allows the water flow to directly act on the acoustic cavity 10, generating sound waves. In this embodiment, when the water flows through the excitation port 11, it will form pressure fluctuations inside the acoustic cavity 10. These fluctuations stimulate the acoustic cavity 10 wall and the internal water to resonate, and this vibration generates sound waves.

[0038] Ideally, the natural frequency of the acoustic cavity 10 matches the frequency of the external excitation, creating resonance. This resonance significantly enhances the intensity of the acoustic signal, enabling it to propagate over longer distances in water. This differs from the traditional method of converting electrical energy into acoustic energy, reducing dependence on electricity.

[0039] The shell 1 is provided with multiple acoustic holes 12, which connect the acoustic cavity 10 to the exterior of the shell 1. These holes 12 are used to transmit sound waves from the acoustic cavity 10 into the water. These holes 12 are the emission points for the sound wave signals within the acoustic cavity 10. The sound waves, resonated and amplified by the acoustic cavity 10, are transmitted through the holes 12 into the surrounding water. The design of the holes 12 optimizes the emission direction and diffusion angle of the sound waves, thereby enhancing signal propagation.

[0040] The sound hole 12 is provided with an adjusting device 2 for adjusting the opening size of the sound hole 12. The adjusting device 2 is used to control the opening of the sound hole 12, thereby adjusting the resonant frequency of the sound wave. By changing the opening of the sound hole 12, the resonance condition of the sound cavity 10 can be adjusted, so that the sound cavity 10 can still maintain the optimal resonance state under different external conditions.

[0041] The opening of the acoustic hole 12 affects the resonance conditions of the acoustic cavity 10. When the adjustment device 2 changes the opening of the acoustic hole 12, the resonant frequency of the acoustic cavity 10 changes. When the opening of the acoustic hole 12 increases, sound waves are released from the acoustic hole 12, increasing the frequency of the sound waves within the acoustic cavity 10 and the resonant frequency. Conversely, when the acoustic hole 12 is closed, the sound waves form standing waves within the acoustic cavity 10, increasing their wavelength and lowering the resonant frequency.

[0042] Standing waves in acoustic cavity 10 are formed by sound waves reflecting within the cavity 10, which affects their wavelength. Adjusting the opening of acoustic hole 12 changes the pattern and wavelength of the standing waves within the cavity 10, thereby adjusting the resonant frequency of the sound waves. Opening the hole affects the propagation path of the sound waves, shortening their wavelength and increasing their resonant frequency. Closing the hole increases the wavelength and decreases the resonant frequency.

[0043] Once the acoustic signal is generated, it propagates into the surrounding water through the acoustic hole 12. The high density and speed of sound in water allow these sound waves to propagate over long distances in water. By adjusting the opening of the acoustic hole 12, the emission effect and propagation range of the sound waves are optimized, ensuring that the sound waves can propagate effectively in the underwater environment, thereby improving the beacon's recognition ability.

[0044] The present invention utilizes water flow to excite the acoustic cavity 10 to generate sound waves. The excitation of the sound waves is passive and does not rely on electrical energy, which reduces the demand for electrical energy and thus reduces power consumption. By utilizing the water flow to directly act on the acoustic cavity 10 to generate sound waves, the step of electrical energy conversion is bypassed, energy loss during the conversion process is reduced, and the overall efficiency of sound wave generation is improved. In addition, the acoustic beacon structure of the present invention is simpler, does not require complex electrical energy conversion equipment, reduces manufacturing and maintenance costs, and improves the endurance of the system, making the acoustic beacon more economical and durable in underwater applications.

[0045] In some preferred embodiments, the front sidewall of the housing 1, facing the direction of motion, is further provided with a water inlet pipe 3 connected to the excitation port 11. This curved structure helps reduce turbulence and flow resistance in the water flow, thereby maintaining the stability and velocity of the water flow. The open end of the water inlet pipe 3 is parallel to the axial direction of the housing 1, ensuring that the water flow enters the pipe directly along the direction of motion of the housing 1, avoiding additional resistance or directional changes during the water flow entry process, and facilitating more efficient use of the water's kinetic energy to excite the acoustic cavity 10.

[0046] The inner diameter of the water inlet pipe 3 gradually increases from the end close to the excitation port 11 to the end away from the excitation port 11. Such a structural setting can accelerate the water flow, reduce energy loss through the gradual expansion effect generated by the pipeline, and make the water flow more effectively impact the excitation port 11. At the same time, the gradually increasing inner diameter setting can maximize the use of the kinetic energy of the water flow, so that less water flow energy can generate a stronger sound wave signal, thereby enhancing the resonance effect in the sound cavity 10.

[0047] The opening at one end of the water inlet pipe 3 close to the excitation port 11 is slit-shaped. This structural setting can converge the water flow into a high-speed water column, which acts more concentratedly on the excitation port 11, thereby improving the efficiency of the water flow in exciting the sound cavity 10 and the intensity of the sound waves.

[0048] As some preferred embodiments, the upper surface of the shell 1 is provided with a plurality of sound holes 12, and the inner diameters of the plurality of sound holes 12 gradually increase from the end away from the excitation port 11 to the end close to the excitation port 11. Thus, the large sound holes 12 close to the excitation port 11 allow high-frequency sound waves to gradually leak out in the area close to the excitation port 11, reducing the accumulation of high-frequency sound waves in the sound cavity 10. This can effectively reduce the high-frequency standing wave mode, thereby weakening the response of the sound cavity 10 to the high-frequency resonant frequency. The small sound holes 12 away from the excitation port 11 help to maintain the reflection of low-frequency sound waves, avoid excessive leakage of low-frequency sound waves in the sound cavity 10, and thus help to adjust the low-frequency resonant frequency.

[0049] The lower surface of the housing 1 is also provided with a plurality of acoustic holes 12, the inner diameters of which gradually increase from the end closest to the excitation port 11 to the end further away from the excitation port 11. Small acoustic holes 12 near the excitation port 11 control the escape of low-frequency sound waves, increasing the retention of low-frequency sound waves by the acoustic cavity 10, thereby improving the stability of low-frequency resonance. Large acoustic holes 12 further away from the excitation port 11 allow high-frequency sound waves to be gradually released, reducing the retention of high-frequency components within the acoustic cavity 10 and thus reducing the impact of high-frequency resonance.

[0050] By configuring the acoustic holes 12 to gradually increase in size, the acoustic energy within the acoustic cavity 10, particularly high-frequency sound waves, can be gradually released, shortening the effective wavelength of the sound waves within the acoustic cavity 10 and thereby gradually increasing the resonant frequency. This adjustment method helps precisely control the resonant frequency of the acoustic cavity 10 to meet specific audio requirements. This configuration allows for varying degrees of adjustment of sound waves of different frequencies, maintaining the effectiveness of low-frequency sound waves while effectively controlling the escape of high-frequency sound waves, thereby optimizing the overall response characteristics of the acoustic cavity 10.

[0051] The configuration of gradually enlarging the upper and lower surface acoustic holes 12 effectively adjusts the resonant frequency of the acoustic cavity 10 by precisely controlling the release and wavelength of sound waves. This design allows the acoustic cavity 10 to exhibit different resonant characteristics at different frequencies, facilitating precise control of specific sound wave requirements.

[0052] When the acoustic beacon is adjusting the resonant frequency, when the sound wave enters the acoustic cavity 10 from the excitation port 11, it will propagate along the length of the acoustic cavity 10. In this process, the sound wave will be reflected in the acoustic cavity 10 and form a standing wave under certain conditions.

[0053] As the acoustic holes 12 on the upper surface of the housing 1 are gradually opened from the end away from the excitation port 11 toward the excitation port 11, sound waves begin to leak out from the portion away from the excitation port 11. This leakage changes the reflection conditions and wavelength of the sound waves within the acoustic cavity 10. By gradually releasing some of the sound wave energy, the effective wavelength within the acoustic cavity 10 is shortened. This shortened wavelength means that the resonant frequency increases.

[0054] The purpose of gradually opening the acoustic holes 12 on the upper surface, from the end distal to the excitation port 11, toward the excitation port 11 is to control the rate and location of sound wave emission. Opening the holes at the distal end first allows for a gradual release of sound wave energy, reducing the number of reflections within the acoustic cavity 10 and increasing the frequency of the sound waves within the cavity 10. This is because when the holes at the distal end are opened first, the low-frequency sound waves are released earlier, while the high-frequency sound waves continue to reflect and resonate within the cavity, thereby increasing the resonant frequency within the cavity.

[0055] After opening the upper surface acoustic holes 12, the lower surface acoustic holes 12 are gradually opened from the end closest to the excitation port 11 toward the end away from the excitation port 11. This further controls the resonant frequency of the sound waves. This opening method ensures a more orderly and uniform release of sound waves at high frequencies. When the acoustic holes 12 near the excitation port 11 are opened, high-frequency sound waves are released preferentially, maintaining the high-frequency resonant mode within the acoustic cavity 10.

[0056] This orderly opening method allows for precise control of the sound wave frequency within the acoustic cavity 10. The acoustic holes 12 are gradually opened from the upper surface to release low-frequency wavelengths, and then from the lower surface to release high-frequency wavelengths. This reduces the wavelength within the acoustic cavity 10 and increases the resonant frequency. This method of operation allows for better adjustment of the sound wave frequency within the acoustic cavity 10, achieving the desired resonant frequency optimization.

[0057] The sound holes 12 on the upper surface gradually increase in inner diameter from the end closest to the excitation port 11 to the end closest to the excitation port 11. This controls the leakage of sound waves, allowing high-frequency sound waves to be gradually released in the area near the excitation port 11, thereby reducing the impact of high frequencies on the acoustic cavity 10. This design helps improve the acoustic cavity 10's resonant frequency response to low frequencies while gradually releasing high-frequency components. The sound holes 12 on the lower surface gradually increase in inner diameter from the end closest to the excitation port 11 to the end further away from the excitation port 11. This effectively controls the leakage of low-frequency sound waves and reduces their accumulation within the acoustic cavity 10. This helps improve the stability of low-frequency resonance while gradually releasing high-frequency components. The gradual increase in the inner diameter of the sound holes 12 allows for more precise adjustment of the resonant frequency of the acoustic cavity 10. The gradually increasing size of the sound holes 12 on the upper surface reduces the impact of high frequencies, while the gradually increasing size of the sound holes 12 on the lower surface controls the retention of low frequencies. This gradual design facilitates more detailed adjustment of the resonant frequency, allowing the acoustic cavity 10 to be optimized across different frequency ranges.

[0058] As another embodiment, the inner diameters of the multiple sound holes 12 on the upper surface of the shell 1 can remain the same from the end away from the excitation port 11 to the end close to the excitation port 11; the inner diameters of the multiple sound holes 12 on the lower surface of the shell 1 also remain the same from the end close to the excitation port 11 to the end away from the excitation port 11.

[0059] When adjusting the resonant frequency, the sound holes 12 are gradually opened from a place away from the excitation port 11 toward the excitation port 11. Even if the inner diameters of these sound holes 12 are the same, as the sound holes 12 are gradually opened, more sound waves will leak out through these sound holes 12, especially high-frequency sound waves. This leakage will cause the sound wave energy in the sound cavity 10 to gradually decrease, and the standing wave wavelength will also be reduced. As the sound holes 12 are gradually opened, the wavelength of the sound waves in the sound cavity 10 becomes shorter under the action of these sound holes 12, because the sound waves can more easily find a path to release. This will shorten the effective length of the sound cavity 10, thereby increasing the resonant frequency.

[0060] As some preferred embodiments, the sound hole 12 includes an adjustment cavity 121 and a sound transmission port 122. The sound transmission port 122 is located on the outer wall of the shell 1, and the adjustment cavity 121 is located on the inner wall of the shell 1 and is connected to the sound transmission port 122 and the sound cavity 10. The inner diameter of the adjustment cavity 121 is larger than the inner diameter of the sound transmission port 122. With this arrangement, the adjustment cavity 121 plays a buffering and regulating role in the propagation of sound waves. By controlling the propagation path of the sound wave in the adjustment cavity 121, the way in which the sound wave enters the sound transmission port 122 can be affected, thereby affecting the sound wave distribution and resonance frequency in the sound cavity 10. Specifically, the inner diameter of the adjustment cavity 121 is larger than the inner diameter of the sound transmission port 122, which makes it easier for the sound wave to pass through the adjustment cavity 121 and enter the sound transmission port 122, thereby facilitating the release of the sound wave from the sound transmission port 122, and avoiding the situation in which the sound wave is blocked and reflected by the inner wall of the shell 1 when adjusting the resonance and cannot be smoothly released from the sound transmission port 122, resulting in a lower frequency.

[0061] The adjustment device 2 is located on the outer wall of the housing 1 and includes an adjustment door 21 and a first servo 22. The first servo 22 is used to rotate the adjustment door 21 to adjust the opening size of the sound port 122. This structural arrangement allows for precise control of the opening of the sound hole 12, thereby adjusting the propagation characteristics and resonant frequency of the sound waves. The first servo 22 is electrically connected to the underwater navigation control unit. This arrangement allows the adjustment door 21 to be operated remotely or automatically. This design allows the opening size of the sound port 122 to be adjusted as needed in different underwater environments, thereby adjusting the resonant characteristics of the acoustic cavity 10 to meet different acoustic requirements or changes in the external environment.

[0062] By coordinating the adjustment chamber 121, the sound transmission port 122, and the adjustment device 2, the acoustic characteristics of the acoustic beacon can be precisely adjusted in underwater environments. Rotating the adjustment door 21 finely controls the opening of the sound transmission port 122, thereby precisely controlling the propagation path, wavelength, and resonant frequency of the sound waves. This design adapts to diverse operating environments, ensuring the acoustic beacon's effective operation in a variety of underwater conditions and improving its performance and adaptability in complex underwater environments.

[0063] Preferably, the inner diameter of the sound port 122 is 1 mm to 30 mm. This range provides a wide range of options to accommodate different sound wave frequencies and underwater environmental requirements. A smaller inner diameter (e.g., 1 mm) helps reduce sound wave leakage at low frequencies, increasing the propagation distance and intensity of the signal. A larger inner diameter (e.g., 30 mm) allows more high-frequency sound waves to pass through, making it suitable for applications requiring higher frequency propagation or rapid adjustment.

[0064] This range of inner diameters helps the beacon maintain stable performance in different underwater environments. For example, a smaller inner diameter can be selected in shallow water to reduce sound wave reflection and interference, while a larger inner diameter can be used in deep water to increase coverage.

[0065] The inner diameter of the adjustment cavity 121 is 1.5 to 5 times the inner diameter of the sound transmission port 122. This ratio range ensures that the adjustment cavity 121 has sufficient space to adjust the transmission characteristics of the sound wave. A larger adjustment cavity 121 (with an inner diameter 5 times that of the sound transmission port 122) provides a larger buffer and adjustment range, allowing for more precise sound wave control. This design is suitable for scenarios that require more precise control of acoustic characteristics, such as frequent or minor adjustments to the sound wave propagation path and resonant frequency in a complex underwater environment. When the inner diameter of the adjustment cavity 121 is 1.5 times the inner diameter of the sound transmission port 122, although the adjustment space is relatively small, it can provide fast response and low acoustic delay, which is suitable for quick and simple adjustment of the sound wave propagation path without significantly changing the sound wave characteristics.

[0066] By adjusting the inner diameter range and ratio of the sound transmission port 122 and the adjustment cavity 121, the beacon can better adjust its sound wave propagation characteristics in different underwater environments. By adjusting the ratio of the adjustment cavity 121 to the sound transmission port 122, more precise acoustic control can be achieved, ensuring that the beacon maintains optimal operating conditions in various complex underwater conditions.

[0067] As some preferred embodiments, the shell 1 is further provided with a resonance port 13 connected to the acoustic cavity 10. The resonance port 13 is located on the bottom surface of the shell 1 away from the excitation port 11, which means that it is at the far end of the acoustic cavity 10. This position usually helps to capture and enhance the low-frequency resonance mode formed in the acoustic cavity 10. The setting of the resonance port 13 allows the acoustic cavity 10 to form a stronger resonance at a specific frequency. It provides an additional sound wave outlet, which can enhance the sound waves of a specific frequency, thereby improving the signal strength of the beacon or the detection capability of the target.

[0068] The outer surface of the housing 1 is provided with a resonant membrane 14 covering the resonant port 13. The combination of the resonant port 13 and the resonant membrane 14 helps to enhance sound waves of a specific frequency within the acoustic cavity 10, improving the detection and recognition capabilities of the acoustic beacon. The provision of the resonant port 13 effectively guides sound waves through the resonant membrane 14, optimizing the propagation of the sound waves.

[0069] The resonance membrane 14 is made of organic polymer materials, composite materials or inorganic materials. Specifically, the membrane material can be made of organic polymer materials such as rubber, plastic, polyurethane, composite materials such as carbon fiber, fiberglass, as well as metal materials such as aluminum, copper, and inorganic materials such as ceramics.

[0070] In some preferred embodiments, a cover 15 and a second steering gear 16 are provided at one end of the water inlet pipe 3, away from the excitation port 11. The second steering gear 16 is used to rotate the cover 15 to open or close the inlet of the water inlet pipe 3. The main function of the cover 15 is to control the flow of water entering the water inlet pipe 3 or to completely seal the water inlet pipe 3. This design allows the inlet of the water inlet pipe 3 to be closed when needed, thereby preventing the water flow or the external environment from affecting the acoustic beacon, or to completely isolate the water flow when the function of the water inlet pipe 3 is not required.

[0071] The second steering engine 16 is electrically connected to the control unit of the underwater vehicle, and the operation of the cover 15 can be carried out by a remote control system. This design allows control to be carried out on the control unit of the underwater vehicle, making the operation more convenient and accurate.

[0072] As some embodiments, see the attached Figure 4 As shown, a towing interface 17 is fixedly provided on the front side of the housing 1 facing the direction of movement, which is used to connect to the vehicle by towing, so that the acoustic beacon can be towed and moved or positioned in the water. This connection method is suitable for situations requiring underwater orienteering or extensive surveys in the water.

[0073] A counterweight 18 is fixed to the lower front surface of the housing 1, facing the direction of motion. This helps lower the acoustic beacon's center of gravity and increase its stability during underwater motion. This reduces the possibility of the acoustic beacon tipping or tilting during towing, ensuring it maintains its predetermined posture and orientation underwater. A stabilizing strap 19 is fixed to the rear end of the housing 1. This strap enhances the acoustic beacon's stability during underwater motion, preventing it from drifting or becoming unstable due to currents or towing forces. This design ensures the acoustic beacon's precise positioning and effective operation during underwater missions.

[0074] When the number of underwater unmanned vehicles in a swarm is large, the adjustment range of the underwater acoustic beacon's operating frequency characteristics needs to be further expanded to accommodate larger swarms. In this case, different acoustic beacons with different characteristics can be combined to generate more line spectra, expanding the applicable swarm size by orders of magnitude.

[0075] For details, please refer to the attached Figure 5 As shown, an underwater acoustic beacon designed for installation in hull 4, designed for a modified model test underwater vehicle, is shown as an example: three underwater acoustic beacons with different operating frequency bands are stacked and mounted at the end of hull 4 via an isolation layer. The three beacons are 20 cm, 15 cm, and 10 cm long, and 10 cm, 7.5 cm, and 5 cm wide, respectively. Each beacon has five upper and three lower acoustic holes 12, with diameters of 10 mm, 0.8 mm, and 0.6 mm, respectively, and longitudinal spacing between the holes 12 of 4 cm, 3 cm, and 2 cm, respectively. The shell 1 is made of polyurethane. The three acoustic beacons have adjustable operating frequencies of 1.5-3.0 kHz, 2.5 kHz-5 kHz, and 4 kHz-8 kHz, respectively, through adjustment gates 21 on the acoustic holes 12. The total sound pressure level exceeds 150 dB at a distance of 1 meter.

[0076] The present invention discloses a method for using an underwater acoustic beacon, which utilizes the underwater acoustic beacon described in the above embodiment and includes the following steps:

[0077] S1. Install the underwater acoustic beacon on the underwater vehicle and keep the acoustic cavity 10 filled with water to ensure that the sound waves can be effectively propagated in the water. The underwater acoustic beacon moves in the water under the drive of the underwater vehicle.

[0078] S2. During the forward movement of the underwater acoustic beacon, the water flows through the water inlet pipe 3 to impact the excitation port 11, and generates underwater acoustic waves and structural resonance in the acoustic cavity 10 of the shell 1. By adjusting the opening and closing states of the acoustic holes 12, passive generation of specific frequencies underwater is achieved. The opening and closing states of the acoustic holes 12 adjust the propagation characteristics of the sound waves, and passive generation of sound waves of specific frequencies can be achieved, that is, no external energy input is required, and the sound waves are generated solely by relying on the water flow and resonance in the acoustic cavity 10.

[0079] S3. When it is necessary to increase the sound wave frequency of the underwater acoustic beacon, the sound hole 12 on the upper surface of the shell 1 is gradually opened from the end of the shell 1 away from the excitation port 11 toward the excitation port 11, and then the sound hole 12 on the lower surface of the shell 1 is gradually opened from the end of the shell 1 close to the excitation port 11 toward the direction away from the excitation port 11.

[0080] As the acoustic holes 12 on the upper surface of the housing 1 are gradually opened from the end away from the excitation port 11 toward the excitation port 11, sound waves begin to leak out from the portion away from the excitation port 11. This leakage changes the reflection conditions and wavelength of the sound waves within the acoustic cavity 10. By gradually releasing some of the sound wave energy, the effective wavelength within the acoustic cavity 10 is shortened. This shortened wavelength means that the resonant frequency increases.

[0081] The purpose of gradually opening the acoustic holes 12 on the upper surface, from the end distal to the excitation port 11, toward the excitation port 11 is to control the rate and location of sound wave emission. Opening the holes at the distal end first allows for a gradual release of sound wave energy, reducing the number of reflections within the acoustic cavity 10 and increasing the frequency of the sound waves within the cavity 10. This is because when the holes at the distal end are opened first, the low-frequency sound waves are released earlier, while the high-frequency sound waves continue to reflect and resonate within the cavity, thereby increasing the resonant frequency within the cavity.

[0082] After opening the upper surface acoustic holes 12, the lower surface acoustic holes 12 are gradually opened from the end closest to the excitation port 11 toward the end away from the excitation port 11. This further controls the resonant frequency of the sound waves. This opening method ensures a more orderly and uniform release of sound waves at high frequencies. When the acoustic holes 12 near the excitation port 11 are opened, high-frequency sound waves are released preferentially, maintaining the high-frequency resonant mode within the acoustic cavity 10.

[0083] This orderly opening method allows for precise control of the sound wave frequency within the acoustic cavity 10. The acoustic holes 12 are gradually opened from the upper surface to release low-frequency wavelengths, and then from the lower surface to release high-frequency wavelengths. This reduces the wavelength within the acoustic cavity 10 and increases the resonant frequency. This method of operation allows for better adjustment of the sound wave frequency within the acoustic cavity 10, achieving the desired resonant frequency optimization.

[0084] S4. When it is necessary to reduce the sound wave frequency of the underwater acoustic beacon, the sound hole 12 on the lower surface of the shell 1 is gradually closed from the end of the shell 1 away from the excitation port 11 toward the excitation port 11, and then the sound hole 12 on the upper surface of the shell 1 is gradually closed from the end of the shell 1 close to the excitation port 11 toward the direction away from the excitation port 11.

[0085] As the sound holes 12 gradually close, the escape of sound waves is restricted, and the sound waves within the acoustic cavity 10 begin to be more effectively retained and reflected. Closing the sound holes 12 on the lower surface first reduces the escape of low-frequency sound waves, while retaining high-frequency sound waves within the acoustic cavity 10, increasing the resonant frequency. Subsequently, closing the sound holes 12 on the upper surface further restricts the reflection and resonance of the sound waves, thereby reducing the frequency of the sound waves.

[0086] First, the far lower surface acoustic holes 12 are closed, allowing high-frequency sound waves to gradually reflect and interfere within the cavity. Subsequently, the acoustic holes 12 near the excitation port 11 are closed, smoothly reducing the sound wave frequency. This method controls the resonance mode of the sound wave, thereby achieving a smooth reduction in the sound wave frequency.

[0087] This gradual closing of the acoustic holes 12 allows for precise control of the reflection and escape of sound waves, thereby reducing their frequency. By adjusting the order and location of the closing of the acoustic holes 12, a desired low-frequency resonance state can be achieved within the acoustic cavity 10. This method results in a smoother reduction in the frequency of the sound waves, ensuring that the acoustic beacon's performance in various applications, such as low-frequency detection or positioning, is met.

[0088] 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 in the scope of protection of the present invention.

Claims

1. An underwater acoustic beacon, characterized in that: The invention comprises a shell (1), wherein the shell (1) has a sound cavity (10) inside, an excitation port (11) is provided on the front side wall of the shell (1) facing the movement direction, the excitation port (11) is used to connect the sound cavity (10) and the outside of the shell (1), and the excitation port (11) can generate water sound waves in the sound cavity (10) under the action of water flow, a plurality of sound holes (12) are provided on the surface of the shell (1), the sound holes (12) are used to connect the sound cavity (10) and the outside of the shell (1), and an adjustment device (2) is provided on the sound hole (12) for adjusting the opening size of the sound hole (12).

2. The underwater acoustic beacon according to claim 1, wherein: The front side wall of the shell (1) facing the direction of movement is further provided with a water inlet pipe (3) connected to the excitation port (11); the water inlet pipe (3) is in an arc-shaped structure; the open end of the water inlet pipe (3) is parallel to the axial direction of the shell (1); the inner diameter of the water inlet pipe (3) gradually increases from the end close to the excitation port (11) to the end away from the excitation port (11); and the opening of the end of the water inlet pipe (3) close to the excitation port (11) is in a slit shape.

3. The underwater acoustic beacon according to claim 2, wherein: The upper surface of the shell (1) is provided with a plurality of sound holes (12), and the inner diameters of the plurality of sound holes (12) remain the same or gradually increase from the end away from the excitation port (11) to the end close to the excitation port (11); the lower surface of the shell (1) is also provided with a plurality of sound holes (12), and the inner diameters of the plurality of sound holes (12) remain the same or gradually increase from the end close to the excitation port (11) to the end away from the excitation port (11).

4. The underwater acoustic beacon according to claim 3, characterized in that: The sound hole (12) comprises an adjustment cavity (121) and a sound transmission port (122); the sound transmission port (122) is located on the outer wall of the shell (1); the adjustment cavity (121) is located on the inner wall of the shell (1) and is connected to the sound transmission port (122) and the sound cavity (10); the inner diameter of the adjustment cavity (121) is larger than the inner diameter of the sound transmission port (122); the adjustment device (2) is located on the outer wall of the shell (1) and comprises an adjustment door (21) and a first steering gear (22); the first steering gear (22) is used to drive the adjustment door (21) to rotate so as to adjust the opening size of the sound transmission port (122); the first steering gear (22) is electrically connected to a control unit for underwater navigation.

5. The underwater acoustic beacon according to claim 4, characterized in that: The inner diameter of the sound transmission port (122) is 1 mm to 30 mm, and the inner diameter of the adjustment cavity (121) is 1.5 to 5 times the inner diameter of the sound transmission port (122).

6. The underwater acoustic beacon according to claim 3, characterized in that: The shell (1) is also provided with a resonance port (13) connected to the acoustic cavity (10); the resonance port (13) is located on the bottom surface of the shell (1) at one end away from the excitation port (11); and the outer surface of the shell (1) is provided with a resonance membrane (14) covering the resonance port (13).

7. The underwater acoustic beacon according to claim 6, characterized in that: The resonance film (14) is made of organic polymer material, composite material or inorganic material.

8. The underwater acoustic beacon according to claim 2, wherein: A sealing cover (15) and a second steering gear (16) are provided at one end of the water inlet pipe (3) away from the excitation port (11); the second steering gear (16) is used to drive the sealing cover (15) to rotate so as to open or close the inlet of the water inlet pipe (3); and the second steering gear (16) is electrically connected to a control unit for underwater navigation.

9. The underwater acoustic beacon according to claim 1, characterized in that: The housing (1) is fixedly provided with a traction interface (17) on the front side facing the direction of movement, for connecting to the aircraft in a towing manner; a counterweight (18) is fixedly provided on the lower surface of the front side facing the direction of movement of the housing (1); and a stabilizing belt (19) is fixedly provided at the rear end of the housing (1).

10. A method for using an underwater acoustic beacon, utilizing the underwater acoustic beacon according to any one of claims 4 to 9, characterized in that: The steps are as follows: S1. Installing the underwater acoustic beacon on the underwater vehicle and keeping the acoustic cavity (10) filled with water, the underwater acoustic beacon moves in the water under the drive of the underwater vehicle; S2. During the forward movement of the underwater acoustic beacon, water flows through the water inlet pipe (3) and impacts the excitation port (11), generating resonance between underwater acoustic waves and the structure in the acoustic cavity (10) of the shell (1). By adjusting the opening and closing state of the acoustic hole (12), passive generation of a specific frequency underwater is achieved; S3. When the sound wave frequency of the underwater acoustic beacon needs to be increased, the sound hole (12) on the upper surface of the shell (1) is gradually opened from the end of the shell (1) away from the excitation port (11) toward the excitation port (11), and then the sound hole (12) on the lower surface of the shell (1) is gradually opened from the end of the shell (1) close to the excitation port (11) toward the direction away from the excitation port (11); S4. When it is necessary to reduce the sound wave frequency of the underwater acoustic beacon, the sound hole (12) on the lower surface of the shell (1) is gradually closed from the end of the shell (1) away from the excitation port (11) toward the excitation port (11), and then the sound hole (12) on the upper surface of the shell (1) is gradually closed from the end of the shell (1) close to the excitation port (11) toward the direction away from the excitation port (11).

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