Float type MEMS vector hydrophone system

Abstract

The invention discloses a float type MEMS vector hydrophone system, and belongs to the technical field of underwater acoustic detection and ocean sensing. The system comprises a buoy, an MEMS vector hydrophone unit, a signal conditioning circuit, an electronic compass module and an output interface unit. The MEMS vector hydrophone unit is installed at the bottom of the buoy, the signal conditioning circuit and the electronic compass module are installed inside the buoy, and the output interface unit is installed at the top of the buoy and comprises two independent watertight plugging interfaces which output analog and digital signals respectively. The system is high in structural integration level, high in attitude sensing capability, excellent in signal quality and suitable for application scenes such as ocean buoy laying, underwater array deployment and distributed underwater acoustic observation.

Description

Technical Field

[0001] This invention belongs to the field of underwater acoustic detection and marine sensing technology, specifically relating to a buoy-type MEMS vector hydrophone system that integrates attitude output and signal conditioning modules. Background Technology

[0002] Hydrophones are core devices for underwater acoustic signal detection and measurement, and are widely used in marine environmental monitoring, underwater communication, underwater acoustic navigation, and target localization. Traditional hydrophones are mainly based on sound pressure levels and cannot obtain directional information of the sound field. Vector hydrophones, on the other hand, can simultaneously sense sound pressure and sound vibration vector components, possessing superior directionality and localization capabilities, and have become a research hotspot in underwater target detection and spatial sound field perception in recent years.

[0003] With the development of microelectromechanical systems (MEMS) technology, ciliary MEMS vector hydrophones, due to their small size, high sensitivity, and strong array integration, are gradually being applied to portable and distributed underwater acoustic detection systems. Some existing studies have proposed integrating MEMS vector hydrophones with electronic compassemblies, using a coaxial packaging method to achieve underwater acoustic vector signal acquisition and attitude compensation functions on a static platform.

[0004] However, in practical marine applications, especially in buoy platform deployment scenarios, traditional coaxial packaging structures have many shortcomings in terms of environmental adaptability, system integration, and deployment flexibility. For example, coaxial packaging structures are mostly used for rigid mounting platforms, making it difficult to adapt to directional errors caused by buoy drift and dynamic attitude changes; existing solutions are mostly geared towards laboratory testing applications and have not formed an integrated system design suitable for long-term deployment and field deployment; in terms of signal conditioning, most are single-stage amplification designs, which have insufficient anti-interference capabilities and limited dynamic range when facing low-frequency underwater acoustic signals; and in terms of power supply and output interfaces, there has been no special optimization for low-power single-supply design and watertight signal transmission schemes in long-term marine deployment environments.

[0005] Therefore, there is an urgent need for an integrated MEMS vector hydrophone system suitable for buoy platforms, which not only has the function of real-time attitude angle output, but also can complete vector signal amplification and filtering through a low-noise two-stage signal conditioning circuit, while supporting single power supply and watertight shielded wire output, so as to improve the system's practicality, reliability and adaptability to marine applications. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of existing MEMS vector hydrophones in buoy platform applications, such as unsuitable packaging, inability to compensate for hydrophone attitude drift, limited signal conditioning capabilities, and output methods unsuitable for underwater environments. The invention provides a buoy-type MEMS vector hydrophone system integrating attitude output and signal conditioning modules. This system is suitable for achieving stable sensing and real-time output of underwater acoustic vector signals on buoy platforms, and has the advantages of compact structure, flexible deployment, and strong adaptability.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A buoy-type MEMS vector hydrophone system includes a buoy, a MEMS vector hydrophone unit, a signal conditioning circuit, an electronic compass module, and an output interface unit.

[0008] The bottom of the buoy has threaded holes for mounting MEMS vector hydrophone units.

[0009] The MEMS vector hydrophone unit is installed at the center of the bottom surface of the buoy. The MEMS vector hydrophone unit is mainly assembled from a polyurethane sound-permeable cap, a stainless steel inner support cap, a fiber cross beam MEMS chip, a printed circuit board, a chip support, a piezoelectric ceramic ring, and a metal substrate. A second hollow threaded post is fixed at the center of the bottom surface of the metal substrate, and the second hollow threaded post is threadedly connected to the threaded hole on the bottom surface of the buoy.

[0010] The signal conditioning circuit is fixedly installed inside the buoy, and performs two-stage amplification and second-order low-pass filtering on the vector signal output by the microfiber crossbeam MEMS chip and the charge signal output by the piezoelectric ceramic ring, respectively.

[0011] The electronic compass module is fixedly installed inside the buoy, with the installation position located in the Z-axis direction of the buoy. It is used to output the three-axis attitude angles of the buoy, uses serial communication output, and is powered by a 3.3V power supply.

[0012] The output interface unit includes two watertight cable interfaces and two watertight cables. The two watertight cable interfaces are located on the top of the buoy. The two watertight cables are connected to the two watertight cable interfaces respectively for transmitting analog signals and digital signals. Both watertight cables are shielded.

[0013] Furthermore, the buoy has a columnar structure and adopts a single-port detachable buoy shell structure, which includes a buoy compartment. A compartment cover can be detachably installed on the top of the buoy compartment. A threaded hole is located at the center of the bottom surface of the buoy compartment, and an O-ring groove is provided on the threaded hole. The threaded hole and the O-ring groove are used to fix and expose the MEMS vector hydrophone unit in the water. The buoy compartment houses a power supply lithium battery, a signal conditioning circuit, and an electronic compass module. The power supply lithium battery supplies power to the signal conditioning circuit through a power transmission line. The signal conditioning circuit is connected to the MEMS vector hydrophone unit through a signal transmission line. Two watertight cable interfaces are located on the compartment cover. One watertight cable interface is an analog signal transmission interface, used to output the analog signal channel of the MEMS vector hydrophone unit after the signal conditioning circuit. The other watertight cable interface is a digital signal transmission interface, used to output the digital attitude angle signal channel output by the MEMS vector hydrophone unit through the electronic compass module.

[0014] Furthermore, the buoy cover and the buoy compartment are fixedly connected by fixing screw holes.

[0015] Furthermore, in the MEMS vector hydrophone unit, the polyurethane acoustic cap is integrally vulcanized and has a dome-shaped shape, which is nested and fixed on the stainless steel inner support cap below. Multiple circular through holes are evenly distributed on the cap body of the stainless steel inner support cap to allow water sound to enter, and its opening has a threaded structure that screws into the connecting frustum at the upper end of the lower metal substrate for fixation. The fibrous crossbeam MEMS chip is mounted on the printed circuit board and fixed by conductive silver paste, while gold wire bonding technology is used to complete the electrical connection between the fibrous crossbeam MEMS chip and the printed circuit board. The printed circuit board is connected to the signal conditioning circuit via conductive silver wires, and signal lines are led out from its pads to achieve pre-amplification, serving as a transition between the MEMS signal and the pre-amplification stage of the signal conditioning circuit. The chip support is an integrally formed metal structure, including a platform for mounting the printed circuit board, with a hollow cylinder fixed at the center of the bottom of the platform, and a piezoelectric ceramic ring. The device is positioned at the bottom of the platform and fitted onto a hollow cylinder as a supplementary sound pressure channel. A first hollow threaded post is formed at the end of the hollow cylinder. A through-hole is provided on the unthreaded section of the hollow cylinder to lead out the electrode leads of the piezoelectric ceramic ring, facilitating the transition between the sound pressure signal and the pre-amplification stage of the signal conditioning circuit. The first hollow threaded post is screwed into a threaded hole at the center of the upper end of the metal substrate to form a mechanical support. The electrode leads of the piezoelectric ceramic ring enter the hollow cylinder through the through-hole, and then enter the buoy compartment through a second hollow threaded post on the bottom surface of the metal substrate, connecting to the signal conditioning circuit. The metal substrate serves as the structural carrier for the entire MEMS vector hydrophone unit. Its upper end has a connecting frustum with a threaded interface for screwing and fixing with a stainless steel inner support cap. Its lower end has a second hollow threaded post for tightening connection with the threaded hole at the bottom of the buoy compartment, achieving reliable assembly and sealed coupling between the MEMS vector hydrophone unit and the buoy compartment.

[0016] Furthermore, the signal conditioning circuit is installed inside the buoy compartment. It includes an LDO single-supply regulator circuit, independent amplifier circuits for the signals from the piezoelectric crossbeam MEMS chip and the piezoelectric ceramic ring, respectively, and a second-order active low-pass filter circuit. In the signal conditioning circuit, the piezoelectric crossbeam MEMS chip signal path includes an AD8422 instrumentation amplifier as the first amplification stage and an ADA4625 non-inverting amplifier circuit as the second amplification stage, and is equipped with a second-order active low-pass filter. The piezoelectric ceramic ring signal path includes an LMC6041 charge amplifier circuit as the first stage and an ADA4625 voltage amplifier circuit as the second stage, and is equipped with a second-order low-pass filter. Both the piezoelectric crossbeam MEMS chip path and the piezoelectric ceramic ring signal path are powered by a 5V single power supply, and a 2.5V DC bias is introduced to achieve a 0-5V linear output, which is compatible with subsequent analog-to-digital conversion or upper-level system acquisition.

[0017] Furthermore, the electronic compass module is installed inside the buoy compartment to acquire the buoy's attitude information in three-dimensional space, including yaw, pitch, and roll angles. The electronic compass module is installed inside the buoy compartment and located on the buoy's Z-axis centerline, collinear with the sensitive direction of the microfiber crossbeam MEMS chip, to achieve precise mapping between attitude angles and acoustic field direction responses. The power supply module operates at 3.3V DC, provided by the system power supply unit via a low-voltage regulator chip, and connects to the host computer via a USB port. Compass data output uses serial communication, via the TX (transmit) and RX (receive) pins, and interacts with the host computer or data acquisition system via a watertight cable.

[0018] Furthermore, two watertight cable interfaces are located on the compartment cover. One watertight cable interface is an analog signal transmission interface, connected to a watertight cable that is an analog signal shielded cable, used to output the analog signal channel after signal conditioning circuitry from the MEMS vector hydrophone unit. The other watertight cable interface is a digital signal transmission interface, connected to a watertight cable that is a digital signal shielded cable, used to output the digital attitude angle signal channel output by the MEMS vector hydrophone unit via the electronic compass module. The two watertight cable interfaces and the two watertight cables are used to connect the system... The acquired analog underwater acoustic signals and digital attitude angle signals are transmitted to external acquisition equipment or upper control systems, respectively. The two watertight cable interfaces and the two watertight cables all adopt high-protection-level watertight connectors and shielded cable structures suitable for marine environments, with good sealing performance and anti-interference capabilities. The two watertight cable interfaces and the two watertight cables all adopt independent shielding and grounding designs. Each cable is covered with a metal shielding layer, and it is ensured that the shielding layer is grounded and conductive with the buoy shell structure at the interface, avoiding electromagnetic coupling interference between digital and analog signals and improving the overall electromagnetic compatibility performance of the system.

[0019] Furthermore, a hydrophone protection component is fixed to the bottom surface of the buoy compartment, and the hydrophone protection component is fitted onto the outside of the MEMS vector hydrophone unit.

[0020] Furthermore, the hydrophone protection component includes a sleeve, one end of which is fixedly connected to the bottom surface of the buoy compartment, and the other end of which is open. Several through holes are provided on the sleeve wall.

[0021] In the buoy-type MEMS vector hydrophone system described in this invention, the signal conditioning circuit adopts a dual-channel design, performing two-stage amplification and second-order low-pass filtering on the MEMS vector signal and the piezoelectric ceramic signal respectively. The overall circuit is powered by a single 5V power supply with an added 2.5V DC bias, achieving stable signal output within the 0~5V range. The electronic compass module is installed at the center of the buoy's Z-axis, outputting three-axis attitude angle information via serial communication, and is powered by a 3.3V power supply module. The output interface unit includes two independent watertight connectors, outputting analog and digital signals respectively, both using shielded cables for transmission, possessing good electromagnetic compatibility and environmental adaptability.

[0022] The buoy-type MEMS vector hydrophone system described in this invention has advantages such as compact structure, high functional integration, excellent signal quality, and real-time attitude output, as specifically demonstrated below: 1) This invention integrates a MEMS vector hydrophone unit, a piezoelectric ceramic sensor (piezoelectric ceramic ring), a signal conditioning circuit, an electronic compass module, a power supply module, etc. into the same buoy. It has a compact structure and a high degree of integration, which facilitates rapid deployment and systematic integration at sea.

[0023] 2) This invention has a built-in electronic compass module that supports real-time output of yaw angle, pitch angle and roll angle, which can realize accurate calibration of the direction information of MEMS vector hydrophone unit, meet the practical needs of vector underwater acoustic signal directivity analysis, spatial calculation and other applications, and expand the scope of application.

[0024] 3) This invention designs independent dual-channel two-stage amplification and filtering circuits for MEMS vector signals and piezoelectric ceramic acoustic pressure signals respectively. It adopts high-performance operational amplifiers, with controllable signal gain and low noise, which is suitable for acquiring weak low-frequency underwater acoustic signals.

[0025] 4) In this invention, the signal conditioning circuit is uniformly powered by a single 5V power supply, and a 2.5V DC bias is added at key nodes, so that the analog signal can be stably output in the range of 0-5V, which is convenient for direct connection to standard AD converters and embedded systems.

[0026] 5) The MEMS vector hydrophone unit in this invention adopts a detachable threaded connection structure, and the cable connector is a standard watertight connector, which facilitates the on-site replacement of MEMS vector hydrophone unit, cable or electronic compass module and improves equipment maintenance efficiency.

[0027] 6) In this invention, analog and digital signals are output through two independent shielded cables, and the shielding layer is reliably grounded, which effectively reduces the risk of signal crosstalk and environmental interference and improves the output stability of long-distance underwater acoustic signals.

[0028] 7) The buoy shell structure of this invention is made of corrosion-resistant aluminum alloy and combined with a watertight sealing structure, which can adapt to harsh environments such as marine floating deployment, surface wave impact and salt spray corrosion, and achieve long-term stable operation.

[0029] 8) This invention simultaneously outputs vector acoustic signals (X and Y axes), sound pressure signals, and three-dimensional attitude angle information, providing multi-source sensing data support for ocean exploration, target positioning, underwater acoustic communication, etc., and has good application scalability.

[0030] In summary, the system of this invention has a high degree of system integration, strong attitude perception capability, and excellent signal quality, making it suitable for applications such as marine buoy deployment, underwater array deployment, and distributed underwater acoustic observation. Attached Figure Description

[0031] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0032] Figure 1 This is a schematic diagram of the overall structure of the buoy-type MEMS vector hydrophone system of the present invention.

[0033] Figure 2 This is a top-view perspective of the buoy in this invention.

[0034] Figure 3 This is a slanted bottom view of the buoy in this invention.

[0035] Figure 4 This is a top-angle view of the MEMS vector hydrophone unit in this invention.

[0036] Figure 5 This is a slanted bottom view of the MEMS vector hydrophone unit in this invention.

[0037] Figure 6 This is an internal view of the buoy in this invention.

[0038] In the diagram: 1-Buoy compartment, 2-Compartment cover, 3-Fixing screw hole, 4-Hydrophone protection component, 5-Polyurethane sound-permeable cap, 6-Stainless steel inner support cap, 7-Circular through hole, 8-Fiber crossbeam MEMS chip, 9-Printed circuit board, 10-Chip support, 11-Piezoelectric ceramic ring, 12-First hollow threaded post, 13-Wire hole, 14-Metal substrate, 15-Connecting frustum, 16-Second hollow threaded post, 17-Analog signal transmission interface, 18-Digital signal transmission interface, 19-Signal conditioning circuit, 20-Electronic compass module, 21-MEMS vector hydrophone unit, 22-Analog signal shielded cable, 23-Digital signal shielded cable. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the present invention will be further described clearly and completely below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0040] In the description of this invention, it should be understood that the terms "top," "bottom," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] like Figures 1 to 6 As shown, this embodiment provides a buoy-type MEMS vector hydrophone system integrating attitude output and signal conditioning modules, including a buoy, a MEMS vector hydrophone unit 21, a signal conditioning circuit 19, an electronic compass module 20, and an output interface unit.

[0042] The buoy has a columnar structure and adopts a single-port detachable buoy shell structure, including a buoy compartment 1 and a compartment cover 2. The compartment cover 2 can be detachably installed on the top of the buoy compartment 1. Specifically, the compartment cover 2 and the top opening of the buoy compartment 1 are fixedly connected through a fixing screw hole 3. The bottom center of the buoy compartment 1 is provided with a threaded hole and an O-ring groove for installing the MEMS vector hydrophone unit 21. The threaded hole and O-ring groove are used to fix and expose the MEMS vector hydrophone unit 21 in the water. The buoy compartment 1 is equipped with a power supply lithium battery, a signal conditioning circuit 19 and an electronic compass module 20. The power supply lithium battery supplies power to the signal conditioning circuit 19 through a power transmission line. The signal conditioning circuit 19 is connected to the MEMS vector hydrophone unit 21 through a signal transmission line.

[0043] The MEMS vector hydrophone unit 21 is installed at the center of the bottom surface of the buoy tank 1. The MEMS vector hydrophone unit 21 is mainly assembled from a polyurethane acoustic cap 5, a stainless steel inner support cap 6, a fiber crossbeam MEMS chip 8, a printed circuit board 9, a chip support platform 10, a piezoelectric ceramic ring 11, and a metal substrate 14. A second hollow threaded post is fixed at the center of the bottom surface of the metal substrate 14. The second hollow threaded post is threadedly connected to a threaded hole at the center of the bottom surface of the buoy tank 1 and sealed through an O-ring groove. The polyurethane acoustic cap 5 is integrally vulcanized and has a dome-shaped shape, nested and fixed to the lower stainless steel inner support cap 6. The stainless steel inner support cap 6... Multiple circular through holes 7 are evenly opened on the cap body of the support cap 6 to allow water sound to enter. At the same time, the cap opening is provided with a threaded structure, which is screwed into the thread on the connecting frustum 15 at the upper end of the metal substrate 14 for fixation. The hair cross beam MEMS chip 8 is mounted on the printed circuit board 9 and fixed by conductive silver paste. At the same time, gold wire bonding technology is used to complete the electrical connection between the hair cross beam MEMS chip 8 and the printed circuit board 9. The signal line led out from the pad on the printed circuit board 9 realizes the pre-output of the hair cross beam MEMS chip 8. The printed circuit board 9 is then connected to the signal conditioning circuit 19 through conductive silver lines, which serves as the transition between the MEMS signal and the pre-amplifier. The chip support 10 is a one-piece molded metal structure with a circular stepped shape. It includes a platform for mounting the printed circuit board 9. A hollow cylinder is fixed at the center of the bottom of the platform. A piezoelectric ceramic ring 11 is disposed at the bottom of the platform and fitted onto the hollow cylinder to sense the sound pressure response inside the polyurethane sound-permeable cap 5, serving as a supplementary sound pressure channel. A first hollow threaded post 12 is formed at the end of the hollow cylinder. A wire hole 13 is opened on the unthreaded section of the hollow cylinder to lead out the electrode lead of the piezoelectric ceramic ring 11 to realize the transition between the sound pressure signal and the pre-amplification of the signal conditioning circuit. The first hollow threaded post 12 is screwed onto the metal substrate 14. Mechanical support is formed in the threaded hole at the center of the end; the electrode lead of the piezoelectric ceramic ring 11 enters the hollow cylinder through the wire hole 13, and then enters the buoy chamber 1 through the second hollow threaded post on the bottom surface of the metal substrate 14, and is connected to the signal conditioning circuit 19; the metal substrate 14 is the structural carrier of the entire MEMS vector hydrophone unit 21, and its upper end is provided with a connecting frustum 15 with a threaded interface for screwing and fixing with the stainless steel inner support cap 6; its lower end is provided with a second hollow threaded post 16 for screwing and connecting with the threaded hole at the bottom of the buoy chamber 1, so as to realize the reliable assembly and sealed coupling of the MEMS vector hydrophone unit 21 and the buoy chamber 1.

[0044] Signal conditioning circuit 19 is installed inside buoy compartment 1, and performs two-stage amplification and second-order low-pass filtering on the vector signal output from the piezoelectric ceramic ring 11 and the charge signal output from the piezoelectric ceramic ring 11, respectively. Signal conditioning circuit module 19 includes an LDO single-supply regulator circuit, independent amplification circuits for the signals from the piezoelectric ceramic ring 11 and the piezoelectric ceramic ring 8, and a second-order active low-pass filter circuit. In the signal conditioning circuit, the signal path of the piezoelectric ceramic ring 8 includes an AD8422 instrumentation amplifier as the first amplifier. The large-scale and ADA4625 in-phase proportional amplifier circuits serve as the second amplification stage, and are equipped with a second-order active low-pass filter. The signal path of the piezoelectric ceramic ring 11 includes an LMC6041 charge amplifier circuit as the first stage and an ADA4625 voltage amplifier circuit as the second stage, and is equipped with a second-order low-pass filter. The signal paths of the fibrous crossbeam MEMS chip 8 and the piezoelectric ceramic ring 11 are both powered by a single 5V power supply, and a 2.5V DC bias is introduced to achieve 0-5V linear output, which is suitable for subsequent analog-to-digital conversion or upper-level system acquisition.

[0045] The electronic compass module 20 is installed inside the buoy, positioned along the Z-axis. It outputs the buoy's three-axis attitude angles via serial communication and is powered by a 3.3V power supply. The electronic compass module 20 acquires the buoy's attitude information in three-dimensional space, including yaw, pitch, and roll angles. Based on a commercial attitude sensor, it is integrated onto a PCB substrate to form a customized attitude sensing subsystem. The electronic compass module 20 is installed inside the buoy compartment 1 and located on the central axis of the buoy's Z-axis, aligned with the sensitive direction of the microfiber crossbeam MEMS chip 8 to achieve precise mapping between attitude angles and sound field direction responses. The power supply module operates at 3.3V DC, provided by the system power supply unit via a low-voltage regulator chip. The power supply module connects to the host computer via a USB port. Compass data output uses serial communication via the TX (transmit) and RX (receive) pins, and digital signal interaction with the host computer or data acquisition system is achieved through a watertight connector cable.

[0046] The output interface unit includes two watertight cable interfaces and two watertight cables communicating with the interior of the buoy compartment 1. The two watertight cable interfaces are located on the compartment cover 2, and the two watertight cables are plugged into the two watertight cable interfaces. One of the watertight cable interfaces is an analog signal transmission interface 17, and the other watertight cable is an analog signal shielded cable 22. The analog signal shielded cable 22 is plugged into the analog signal transmission interface 17 and is used to output the analog signal channel of the MEMS vector hydrophone unit 21 after passing through the signal conditioning circuit 19. The other watertight cable interface is a digital signal transmission interface 18, and the other watertight cable is a digital signal shielded cable 23. The digital signal shielded cable 23 is plugged into the digital signal transmission interface 18 and is used to output the digital attitude angle signal channel output by the MEMS vector hydrophone unit 21 through the electronic compass module 20. The analog signal shielded cable 22 and the analog signal transmission interface 17, and the digital signal shielded cable 23 and the digital signal transmission interface 18 form two independent watertight connector cable systems. These systems are used to transmit the analog underwater acoustic signals and digital attitude angle signals acquired by the system to external acquisition equipment or upper control systems, respectively. Both systems adopt high-protection-level watertight connectors and shielded cable structures suitable for marine environments, possessing excellent sealing performance and anti-interference capabilities. The analog signal shielded cable 22 is connected to the analog signal transmission interface 17 and is used to output the X-axis and Y-axis signals, piezoelectric ceramic ring 11 signals, positive power supply, and ground of the MEMS vector hydrophone unit 21. The digital signal shielded cable 23 is connected to the digital signal transmission interface 18 and is used to output the TX, RX, 3.3V power supply, and digital ground of the electronic compass module 20. Both watertight connector cable interfaces adopt an independent shielding and grounding design. Both watertight connector cables are covered with a metal shielding layer, ensuring that the shielding layer is grounded and conductive with the buoy shell at the interface, avoiding electromagnetic coupling interference between digital and analog signals, and improving the overall electromagnetic compatibility performance of the system.

[0047] A hydrophone protection component 4 is fixed on the bottom surface of the buoy tank 1. The hydrophone protection component 4 is fitted outside the MEMS vector hydrophone unit 21. The hydrophone protection component 4 includes a sleeve. One end of the sleeve is fixedly connected to the bottom surface of the buoy tank 1. The other end of the sleeve is open. Several through holes are opened on the sleeve wall.

[0048] The working principle of the buoy-type MEMS vector hydrophone system with integrated attitude output and signal conditioning module described in this embodiment is as follows: After the buoy-type MEMS vector hydrophone system is submerged, when sound waves generated by an underwater target or sound source propagate to the buoy's position, the sound waves are transmitted to the interior through the polyurethane sound-permeable cap 5. The vibration of particles in the sound field causes a slight deformation of the ciliated crossbeam MEMS chip 8, resulting in a change in the resistance value on the crossbeam chip. This change is then converted into a voltage value through a Wheatstone bridge, realizing the conversion of sound to force to electricity. Simultaneously, the sound pressure signal causes a slight deformation of the piezoelectric ceramic ring 11, generating an additional charge output as a supplementary sound pressure channel. Then, the MEMS vector circuit signal first enters the AD8422 instrumentation amplifier for high common-mode rejection ratio amplification, followed by a second-stage gain amplification through an in-phase amplifier circuit composed of ADA4625, and finally outputs a stable analog signal after filtering out high-frequency interference through an active second-order low-pass filter. The ceramic signal first undergoes charge-to-voltage conversion by a charge amplifier, and then is amplified and shaped by an ADA4625 voltage amplifier and a low-pass filter, outputting a voltage signal corresponding to the sound pressure. The electronic compass module 20 senses the spatial attitude changes of the system in real time and outputs the current yaw, pitch, and roll angle data via serial port for the host system to perform orientation compensation, beam reconstruction, or attitude self-alignment. Finally, all analog and digital signals are output to external devices through two independent watertight connector cable interfaces and watertight connector cables.

[0049] The buoy-type MEMS vector hydrophone system with integrated attitude output and signal conditioning module described in this embodiment achieves a high degree of integration of underwater acoustic vector signal acquisition, sound pressure supplementation channel, attitude angle sensing, signal conditioning, and shielded output on the buoy platform through the above structural design and system integration. It is suitable for complex application scenarios such as marine buoy deployment, underwater monitoring arrays, and vector underwater acoustic target positioning.

[0050] The embodiments described above merely illustrate the preferred implementation of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A buoy-type MEMS vector hydrophone system, characterized in that, Includes buoys, MEMS vector hydrophone units, signal conditioning circuits, electronic compass modules, and output interface units; The bottom of the buoy is provided with threaded holes for mounting MEMS vector hydrophone units; The MEMS vector hydrophone unit is installed at the center of the bottom surface of the buoy. The MEMS vector hydrophone unit is mainly assembled from a polyurethane sound-permeable cap, a stainless steel inner support cap, a fiber cross beam MEMS chip, a printed circuit board, a chip support, a piezoelectric ceramic ring, and a metal substrate in sequence. A second hollow threaded post is fixed at the center of the bottom surface of the metal substrate, and the second hollow threaded post is threadedly connected to the threaded hole on the bottom surface of the buoy. The signal conditioning circuit is fixedly installed inside the buoy and performs two-stage amplification and second-order low-pass filtering on the vector signal output by the microfiber crossbeam MEMS chip and the charge signal output by the piezoelectric ceramic ring, respectively. The electronic compass module is fixedly installed inside the buoy, with the installation position located in the Z-axis direction of the buoy. It is used to output the three-axis attitude angles of the buoy, uses serial communication output, and is powered by a 3.3V power supply. The output interface unit includes two watertight cable interfaces and two watertight cables. The two watertight cable interfaces are located on the top of the buoy. The two watertight cables are connected to the two watertight cable interfaces respectively for transmitting analog signals and digital signals. Both watertight cables are shielded.

2. The buoy-type MEMS vector hydrophone system according to claim 1, characterized in that: The buoy has a columnar structure and adopts a single-port detachable buoy shell structure, which includes a buoy compartment. The top of the buoy compartment is detachably fitted with a compartment cover. A threaded hole is located at the center of the bottom surface of the buoy compartment, and an O-ring groove is provided on the threaded hole. The threaded hole and the O-ring groove are used to fix and expose the MEMS vector hydrophone unit in the water. The buoy compartment contains a power supply lithium battery, a signal conditioning circuit, and an electronic compass module. The power supply lithium battery supplies power to the signal conditioning circuit through a power transmission line, and the signal conditioning circuit is connected to the MEMS vector hydrophone unit through a signal transmission line.

3. The buoy-type MEMS vector hydrophone system according to claim 2, characterized in that: The buoy cover and the buoy compartment are fixedly connected by fixing screw holes.

4. The buoy-type MEMS vector hydrophone system according to claim 2, characterized in that: In the MEMS vector hydrophone unit, the polyurethane acoustically transparent cap is integrally vulcanized and has a dome-shaped shape. It is nested and fixed on the stainless steel inner support cap below. Multiple circular through holes are evenly distributed on the cap body of the stainless steel inner support cap to allow water sound to enter. The cap opening has a threaded structure that screws into the connecting frustum at the upper end of the lower metal substrate for fixation. The fibrous crossbeam MEMS chip is mounted on a printed circuit board and fixed by conductive silver adhesive. Gold wire bonding technology is used to complete the electrical connection between the fibrous crossbeam MEMS chip and the printed circuit board. The printed circuit board is connected to the signal conditioning circuit via conductive silver wires. Signal lines are led out from its pads to achieve pre-amplification, serving as a transition between the MEMS signal and the pre-amplification stage of the signal conditioning circuit. The chip support is an integrally formed metal structure, including a platform for mounting the printed circuit board. A hollow cylinder is fixed at the center of the bottom of the platform, and a piezoelectric ceramic ring is placed on it. The bottom of the platform is fitted onto a hollow cylinder as a supplementary sound pressure channel. The end of the hollow cylinder forms a first hollow threaded post. A through hole is opened on the unthreaded section of the hollow cylinder to lead out the electrode leads of the piezoelectric ceramic ring to realize the transition between the sound pressure signal and the pre-amplification of the signal conditioning circuit. The first hollow threaded post is screwed into the threaded hole at the center of the upper end of the metal substrate to form a mechanical support. The electrode leads of the piezoelectric ceramic ring enter the hollow cylinder through the through hole, and then enter the buoy compartment through the second hollow threaded post on the bottom surface of the metal substrate, connecting with the signal conditioning circuit. The metal substrate is the structural carrier of the entire MEMS vector hydrophone unit. Its upper end has a connecting frustum with a threaded interface for screwing and fixing with the stainless steel inner support cap. Its lower end has a second hollow threaded post for screwing tightly into the threaded hole at the bottom of the buoy compartment, realizing reliable assembly and sealed coupling between the MEMS vector hydrophone unit and the buoy compartment.

5. The buoy-type MEMS vector hydrophone system according to claim 4, characterized in that: The signal conditioning circuit is installed inside the buoy compartment and includes an LDO single-supply regulator circuit, independent amplifier circuits for the signals from the piezoelectric crossbeam MEMS chip and the piezoelectric ceramic ring, respectively, and a second-order active low-pass filter circuit. In the signal conditioning circuit, the piezoelectric crossbeam MEMS chip signal path includes an AD8422 instrumentation amplifier as the first amplification stage and an ADA4625 non-inverting amplifier circuit as the second amplification stage, with a second-order active low-pass filter. The piezoelectric ceramic ring signal path includes an LMC6041 charge amplifier circuit as the first stage and an ADA4625 voltage amplifier circuit as the second stage, with a second-order low-pass filter. Both the piezoelectric crossbeam MEMS chip signal path and the piezoelectric ceramic ring signal path are powered by a single 5V supply, with a 2.5V DC bias introduced to achieve a 0-5V linear output, suitable for subsequent analog-to-digital conversion or upper-level system acquisition.

6. The buoy-type MEMS vector hydrophone system according to claim 5, characterized in that: The electronic compass module is installed inside the buoy compartment to acquire the buoy's attitude information in three-dimensional space, including yaw, pitch, and roll angles. The module is located on the buoy's Z-axis centerline and is aligned with the sensitive direction of the microfiber crossbeam MEMS chip to achieve precise mapping between attitude angles and acoustic field direction responses. The power supply module operates at 3.3V DC and connects to the host computer via a USB port. Compass data output uses serial communication via transmit and receive pins, and digital signal interaction with the host computer or data acquisition system is achieved through a watertight cable.

7. The buoy-type MEMS vector hydrophone system according to claim 6, characterized in that: Two watertight cable interfaces are located on the compartment cover. One watertight cable interface is an analog signal transmission interface, connected to a watertight cable that is an analog signal shielded cable, used to output the analog signal channel after signal conditioning circuitry from the MEMS vector hydrophone unit. The other watertight cable interface is a digital signal transmission interface, connected to a watertight cable that is a digital signal shielded cable, used to output the digital attitude angle signal channel output by the MEMS vector hydrophone unit via the electronic compass module. These two watertight cable interfaces and two watertight cables are used to collect data from the system. The analog underwater acoustic signals and digital attitude angle signals are transmitted to external acquisition equipment or upper control systems respectively; both watertight connectors and both watertight cables adopt high protection level watertight connectors and shielded cable structures suitable for marine environments, with good sealing performance and anti-interference ability; both watertight connectors and both watertight cables adopt independent shielding and grounding design, each cable is wrapped with a metal shielding layer, and the shielding layer is grounded and conductive with the buoy shell structure at the interface, avoiding electromagnetic coupling interference between digital signals and analog signals, and improving the overall electromagnetic compatibility performance of the system.

8. The buoy-type MEMS vector hydrophone system according to claim 2, characterized in that: Hydrophone protection components are fixed on the bottom surface of the buoy compartment, and these components are fitted onto the outside of the MEMS vector hydrophone unit.

9. The buoy-type MEMS vector hydrophone system according to claim 8, characterized in that: The hydrophone protection component includes a sleeve, one end of which is fixedly connected to the bottom surface of the buoy compartment, and the other end of which is open. Several through holes are provided on the sleeve wall.

Images