Hydrophone-based underwater equipment monitoring system and control method

Abstract

The application discloses an underwater equipment monitoring system and control method based on a hydrophone, and belongs to the technical field of underwater sensing and large-scale security defense. The system comprises an underwater defense area physical structure arranged at a ship double bottom and a seawater valve box, an acoustic and physical dual-mode sensing hydrophone device, a feature recognition terminal and a ship-shore cooperative communication module; the hydrophone cable is arranged in a U-shaped structure at a submarine door grating to synchronously monitor acoustic frequency oscillation and mechanical deformation data; the feature recognition terminal executes acoustic feature classification and physical state mutation dual verification logic; when high confidence intrusion is determined, the ship-shore cooperative communication module broadcasts alarm through a ship automatic identification system binary special application message to trigger a shore-based interlocking countermeasure. The application realizes ship-shore cooperative automatic underwater security and defense closed loop through acoustic and physical dual-mode orthogonal verification, and significantly reduces the false alarm rate in a complex marine environment.

Description

Technical Field

[0001] This invention relates to the field of underwater sensing and large-scale security defense technology. Specifically, it relates to a comprehensive early warning system and control method that integrates optical fiber or piezoelectric hydrophone arrays for acoustic signature extraction and physical triggering mechanism for orthogonal state verification. Background Technology

[0002] Underwater sabotage threats against large merchant ships, military vessels, and critical port infrastructure while anchored are characterized by high concealment and complex technical methods. Sabotage operations typically involve closed-loop respirators and miniature underwater unmanned propulsion systems. Furthermore, autonomous underwater vehicles (AUVs) or miniature underwater unmanned vehicles (UUVs) often employ sound-absorbing rubber coatings and low-noise propeller designs when performing close-in reconnaissance and explosive ordnance deployment missions, posing a significant challenge to traditional active detection methods.

[0003] The underwater section of the hull plate V of modern large ships contains a specific high-risk area—the seawater valve box. As a complex hydrodynamic structure with a direct opening to the sea surface and a porous internal cavity, the seawater valve box primarily provides seawater intake channels for the ship's main and auxiliary generator cooling systems, ballast water systems, and fire suppression systems. This unique underwater cavity, coupled with the external seabed grille 6 designed to prevent the inhalation of large marine organisms and debris, provides an excellent hiding and attachment point for non-invasive underwater forces. Criminals often attach unusual objects to the grille base 7 or use cutting equipment to cut through the grille and infiltrate the ship's double bottom III intake pipes to carry out sabotage activities. Because electrolytic antifouling operations are frequently involved inside the seawater valve box, and there is often a cavitation flow field from seawater erosion, the environmental background noise is extremely complex.

[0004] Currently, underwater security solutions for this area mainly rely on two types of methods, but both have significant bottlenecks in engineering application: The first category is acoustic detection methods, primarily employing active sonar or passive acoustic arrays. However, when active sonar is deployed in confined spaces such as shallow water ports, narrow berths, and seawater valve boxes, it inevitably encounters extremely severe reverberation interference and multipath effects. Multiple reflections of active sound waves between the ship's hull, seabed, and breakwater create strong interference clutter, causing the sonar screen to be covered in noise, making it almost impossible to distinguish tiny anechoic targets. Passive listening networks based on piezoelectric or traditional interferometric fiber optic hydrophones have an extremely high false alarm rate in actual harbor engineering deployments. The harbor environment is filled with cavitation noise from other ships' propellers, anchoring sounds, pile driving sounds, and the sounds of marine life. If the system relies solely on a single sound intensity threshold or frequency band energy integral for alarms, false alarms will be frequently triggered.

[0005] The second category involves physical isolation or physical sensing methods, such as fiber optic anti-submarine nets or tripwire alarm systems based on fiber optic vibration sensing. Existing patents have proposed fiber optic barrier net technologies for aquaculture, marine ranch anti-theft, or high-speed rail anti-climbing. These systems typically generate alarms by utilizing fiber optic bending loss or phase disturbances caused by external intrusion. However, directly applying these systems to ship submarine doors presents a fatal weakness: ocean currents, floating abandoned fishing nets, or collisions with large sea fish can all apply sufficient physical tension to the cables, triggering false alarms. Furthermore, purely physical tripwires are completely undetectable by hovering underwater robots that silently float near valve boxes for non-contact eavesdropping or reconnaissance.

[0006] Furthermore, regarding the flow and countermeasures of security alarms, existing underwater detection equipment for ships is mostly a closed, internal system. Alarm information is only displayed on a separate host computer in the ship's bridge or security room. When a ship is anchored or berthed, localized alarms may not be detected immediately due to crew members being on low manning or resting. Currently, there is no technical standard that can deeply couple such high-intensity underwater attack alarms with the globally deployed Automatic Identification System (AIS) at the underlying communication format level. This prevents port traffic control centers and coastal defense systems from completing adaptive countermeasure scheduling and underwater verification within the golden window of attack. Summary of the Invention

[0007] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and propose an underwater equipment monitoring system and control method based on hydrophones. The system uses dual concurrent orthogonal verification of acoustic weak feature recognition and physical deformation perception to carry out ship security control, effectively addressing the problems of high false alarm rate, low defense reliability and lack of ship-shore linkage mechanism caused by the susceptibility of single-mode detection to interference from complex marine environmental noise and ship vibration.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A hydrophone-based underwater equipment monitoring system includes: The underwater defense zone physical structure is deployed at the double bottom of the ship and the seawater valve box, and the seawater valve box is equipped with a seabed gate grille on the outside; The acoustic and physical dual-modal sensing hydrophone device uses hydrophone cables to form a U-shaped tripwire structure on and around the seabed gate grid, which is used to simultaneously monitor underwater environmental acoustic frequency oscillation data as well as low-frequency mechanical deformation or tension data of the U-shaped tripwire structure caused by external pulling or cutting. A feature recognition terminal, connected to the sensing device, is used to demodulate the acquired data and execute dual verification logic based on acoustic feature classification and physical state abrupt changes; and The ship-shore collaborative communication module, connected to the feature recognition terminal, is used to broadcast alarm data to the outside world using the ship-shore network when the dual verification logic determines that it is a high-confidence intrusion event.

[0009] In the above technical solution, the hydrophone cable includes a consumable cable segment, which is arranged along the wall of the seawater valve box and connected to the hydrophone sensing end through a flexible cable bracket. Its upper end is connected to the double bottom through a high-voltage waterproof cable quick-release connector. The U-shaped tripwire structure is wrapped in a U-shape around the bottom door fixing buckle at the top of the seawater valve box door, serving as a trigger tripwire for detecting physical pulling.

[0010] In the above technical solution, the seawater valve box is located on the underwater part of the hull plate, the double bottom is located above the seawater valve box and is connected to the seawater valve box, the seabed gate grid covers the outside of the opening of the seawater valve box to the sea surface, and the grid base is supported on the bottom of the seabed gate grid.

[0011] In the above technical solution, the easily damaged cable segment of the hydrophone cable is detachably connected to the armored main cable or transmission cable at the double bottom through the cable quick-release connector. The flexible cable bracket is arranged at intervals on the anti-corrosion wall of the seawater valve box to fix and suspend the hydrophone sensing end in the cavity between the seawater valve box wall and the seabed gate grid.

[0012] In the above technical solution, the hydrophone cable U-shaped tripwire structure is specially encapsulated at the end of the hydrophone cable, set in the outer area of ​​the seabed gate grille, and wrapped in a U-shape around the seabed gate fixing buckle located at the top of the seawater valve box door. The sheath of the U-shaped tripwire structure has stronger tensile strength than the cable body and is sensitive to stress deformation.

[0013] In the above technical solution, the acoustic and physical dual-modal sensing hydrophone device is an optical fiber sensor. Its above-water end includes a narrow-linewidth laser, an acousto-optic modulator, an erbium-doped fiber amplifier, and an optical circulator connected in sequence via optical paths. Its underwater end has an optical fiber hydrophone probe connected to the armored main cable. When the U-shaped tripwire structure is physically damaged, the change in its optical path difference and the phase shift and intensity attenuation of the interference optical field caused by the macrobending loss of the optical fiber serve as physical sensing trigger signals.

[0014] In the above technical solution, the fiber optic hydrophone probe is located at the underwater end and is sealed to the armored main cable. The armored main cable passes through the internal cabin of the ship and reaches the double bottom. It is then connected to the optical path of the easily damaged cable section of the hydrophone cable via the cable quick-release connector. The narrow linewidth laser, acousto-optic modulator, erbium-doped fiber amplifier, and optical circulator are sequentially connected to each other and located at the above-water end.

[0015] In the above technical solution, the acoustic and physical dual-modal sensing hydrophone device is a piezoelectric acoustic sensor. Its underwater end includes a piezoelectric ceramic and a preamplifier that is impedance matched and directly connected to it. Its above-water end is equipped with a low-noise power supply module and a signal conditioner, a high-speed data acquisition instrument and a processing terminal connected in sequence. The U-shaped tripwire structure integrates a mechanical tension switch or an electromagnetic on / off circuit to generate a hard interruption physical alarm signal.

[0016] In the above technical solution, the piezoelectric ceramic array is disposed at the underwater end and is covered with a sound-transmitting layer that matches the acoustic impedance of seawater. The piezoelectric ceramic is directly connected to the preamplifier. The preamplifier is connected to the signal conditioner at the surface end via a transmission cable. The low-noise power module provides DC power to the underwater end via a through-cabin power supply cable.

[0017] In the above technical solution, the abovewater end of the acoustic and physical dual-modal sensing hydrophone device is uniformly installed in the ship's safety control room or bridge, and its underwater end reaches the double bottom after passing through the cabin penetration part inside the ship via the main transmission cable. At the junction of the double bottom and the seawater-filled seawater valve box, it is connected to the hydrophone cable arranged along the wall of the seawater valve box via the cable quick-release connector.

[0018] In the above technical solution, the feature recognition terminal has a built-in audio frequency extraction algorithm based on intelligent algorithms. By pre-emphasizing, framing and windowing the broadband underwater acoustic signal, the logarithmic energy spectrum is extracted through fast Fourier transform and nonlinear mapping of scale triangular filter bank, and then discrete cosine transform is performed to deeply extract the feature vector of the respiratory rhythm and weak dynamic mechanical frequency cepstral coefficient of the concealed target, and match it with the preset voiceprint library execution matrix to generate a preliminary acoustic alarm.

[0019] In the above technical solution, the feature recognition terminal has built-in dual concurrent orthogonal verification logic, which establishes an extremely short judgment time window on the time axis. Only when the system synchronously or successively detects high-confidence acoustic intrusion alarms and abnormal physical macro-bend phase shift or open circuit alarms of U-shaped tripwire structures, it performs logic fusion and outputs a true high-confidence intrusion alarm flag to eliminate false alarms caused by a single factor.

[0020] The acoustic and physical dual verification logic is as follows: a judgment time window is established on the time axis; when the system detects the acoustic intrusion preliminary alarm setting, and within the same time window, the system synchronously or successively detects the physical macro-bend phase change alarm or mechanical circuit break alarm of the hydrophone cable U-shaped tripwire structure (5), the two types of alarms are verified by AND logic operation; and a high confidence intrusion alarm flag is output to eliminate false alarms induced by a single factor.

[0021] That is, only when both logics are true will the high-confidence intrusion alarm flag be output to eliminate false alarms induced by a single factor.

[0022] In the above technical solution, the binary dedicated application message of the Automatic Identification System (AIS) is invoked to broadcast alarm data to a high-frequency channel, thereby triggering the interlocking countermeasure scheduling of the shore-based port security platform.

[0023] In the above technical solution, the ship-shore collaborative communication module has a built-in millisecond-level ship-shore linkage control mechanism. After establishing a high-confidence alarm, it can broadcast encrypted data to the high-frequency channel by calling the binary dedicated application message of the Automatic Identification System without manual intervention; trigger the shore-based port security platform to automatically interlock and shut down seabed construction operations around the target, issue a shutdown command to prohibit berthed ships from using high-power thruster tests, and deploy an underwater robot to perform on-site verification and countermeasures.

[0024] In the above technical solution, when a high-confidence intrusion alarm flag is generated, the ship-shore collaborative communication module calls the binary dedicated application message of the Automatic Identification System (AIS) to broadcast an alarm data stream containing the attacked ship's identification code, precise coordinates, timestamp, and pre-programmed intrusion type to a high-frequency channel.

[0025] A control method for an underwater equipment monitoring system based on a hydrophone includes the following steps: S1 Real-time Monitoring Steps: The shipborne processing terminal receives environmental acoustic data collected by hydrophones deployed at the seawater valve box in real time, and simultaneously receives physical tension or deformation data of the U-shaped tripwire structure laid at the seabed gate grid in real time. S2 Acoustic Early Warning Judgment Step: Input the acoustic data into the preset abnormal sound source identification model for feature matching. When frogman breathing apparatus noise, metal cutting sound or underwater propulsion noise is identified, a first early warning signal is generated. S3 Physical Early Warning Judgment Step: Synchronously monitor the U-shaped tripwire structure. When a sudden change in tension or deformation caused by external pulling or cutting is detected, a second early warning signal is generated. S4 Dual Verification Diagnosis Step: Determine whether the first warning signal and the second warning signal are triggered simultaneously or successively within a set time window. If so, perform an AND logic operation to generate a high-confidence intrusion alarm. S5 Alarm and Data Reporting Steps: The high-confidence intrusion alarm and abnormal data are broadcast to a high-frequency channel via the ship-shore collaborative communication module in the Automatic Identification System (AIS) binary dedicated application message format; and S6 Ship-Shore Joint Response Steps: After receiving and analyzing the alarm, the shore-based port security platform automatically interlocks and shuts down the surrounding seabed construction operations based on the target vessel's latitude and longitude, issues a shutdown command to the berthing vessel, and deploys an underwater robot to the target seawater valve box location to perform on-site verification and countermeasures.

[0026] The on-site verification mentioned above includes video verification and / or image verification.

[0027] In the above technical solution, in the acoustic early warning judgment step, the collected broadband underwater acoustic signal is pre-emphasized, framed and windowed in sequence, converted into power spectral density by fast Fourier transform, logarithmic energy spectrum is extracted by nonlinear frequency mapping through scale triangular filter bank, frequency cepstral coefficient feature vector is extracted by discrete cosine transform, and matrix matching of cosine similarity and Mahalanobis distance is performed with the preset voiceprint library. If the deviation is lower than the preset safety threshold, an acoustic intrusion preliminary alarm is generated.

[0028] In the above technical solution, in the dual verification diagnosis step, a judgment time window is established on the time axis. Only when the acoustic intrusion preliminary alarm and the physical macro-bend phase change alarm or mechanical circuit breaker alarm of the U-shaped tripwire structure occur synchronously or successively, the logic fusion is performed to output a high-confidence intrusion alarm flag.

[0029] In the above technical solution, the acoustic and physical dual verification logic is specifically as follows: a judgment time window is established on the time axis; when the system detects the acoustic intrusion preliminary alarm being set, and within the same time window, the system synchronously or successively detects the physical macro-bend phase change alarm or mechanical circuit break alarm of the hydrophone cable U-shaped tripwire structure, the two types of alarms are verified by AND logic operation; only when both logics are true, a high-confidence intrusion alarm flag is output to eliminate false alarms induced by a single factor.

[0030] Therefore, this invention discloses an underwater equipment monitoring system and control method based on hydrophones. The system includes an underwater defense zone physical structure deployed at the double bottom and seawater valve box of the ship, an acoustic and physical dual-modal sensing hydrophone device, a feature recognition terminal, and a ship-shore collaborative communication module. The hydrophone cable is laid at the seabed gate grid to form a U-shaped tripwire structure, simultaneously monitoring acoustic oscillation and mechanical deformation data. The feature recognition terminal performs dual verification logic of acoustic feature classification and physical state change. When a high-confidence intrusion is detected, the ship-shore collaborative communication module broadcasts an alarm through the Automatic Identification System (AIS) binary dedicated application message, triggering shore-based interlocking countermeasures. This invention significantly reduces the false alarm rate in complex marine environments through acoustic and physical dual-modal orthogonal verification, achieving an automated underwater security closed loop with ship-shore collaboration.

[0031] Compared with the prior art, the beneficial effects of this invention are: Significantly reducing false alarm rates and improving detection reliability, this invention innovatively integrates acoustic listening and physical deformation sensing for orthogonal verification. By reconstructing the hydrophone topology at the seabed gate grille to form a U-shaped tripwire structure, it simultaneously collects acoustic oscillation data and low-frequency mechanical deformation or tension data, and establishes a decision window on the time axis to perform rigorous AND logic operations. This dual concurrent verification mechanism effectively eliminates false alarms caused by factors such as single ocean background noise, ship vibration, marine life impacts, and undercurrents, solving the engineering bottleneck of extremely high false alarm rates in traditional passive acoustic detection or purely physical tripwire systems.

[0032] Accurately identify weak and concealed targets. This invention employs an intelligent algorithm-based voiceprint feature extraction mechanism. Through pre-emphasis, fast Fourier transform, nonlinear mapping of scale triangular filter banks, and discrete cosine transform, it deeply extracts the weak frequency cepstral coefficient feature vectors of concealed targets such as frogman breathing rhythms and low-noise thrusters of micro underwater vehicles. These vectors are then matched with a pre-set voiceprint database using cosine similarity and Mahalanobis distance matrix, significantly improving the sensitivity and accuracy of identifying weak targets under complex cavitation flow field background noise.

[0033] Constructing a ship-shore collaborative automated early warning and countermeasure network. This invention breaks through the closed and isolated state of existing underwater ship detection equipment, pioneering a deep coupling of high-intensity underwater attack alarms with the Automatic Identification System (AIS) at the underlying communication format. After the alarm is generated, the link is automatically converted into a regional security broadcast. Based on the standardized data, the port control center implements second-level interlocking shutdown and calls upon underwater robots, realizing a shift from passive monitoring to proactive multi-dimensional collaborative countermeasures.

[0034] Millisecond-level encrypted broadcasts are achieved using binary dedicated application messages. Upon receiving the message, the port security platform can automatically complete second-level interlocking control based on the precise coordinates of the target vessel. This includes shutting down surrounding seabed construction operations, prohibiting high-power thruster testing, and automatically dispatching underwater robots to approach and verify the information. This achieves a security closed loop from passive monitoring to proactive multi-dimensional collaborative countermeasures, significantly reducing response latency during the golden window of opportunity.

[0035] Adaptable to complex underwater engineering environments. This invention addresses the unique cavity structure and highly corrosive environment of seawater valve boxes by designing a quick-release cable connector with high-pressure waterproof performance, a flexible cable support, and easily damaged cable sections. This ensures reliability under long-term immersion conditions while facilitating rapid replacement and maintenance during dry dock maintenance. Furthermore, it provides two optional dual-modal sensing architectures: fiber optic interferometer and piezoelectric ceramic, balancing the engineering requirements of high-sensitivity detection and high-reliability hard-interruption alarms in harsh environments. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1This is a structural diagram of the acoustic sensing system of the ship's end seabed valve box in the underwater equipment monitoring system based on hydrophones according to the present invention. Figure 2 This is a hardware block diagram of the fiber optic hydrophone sensor of the present invention. Figure 3 This is a hardware principle block diagram of the piezoelectric hydrophone sensor of the present invention; Figure 4 This is a flowchart illustrating the steps of the underwater equipment monitoring system and control method based on hydrophones according to the present invention.

[0037] The corresponding labels in the attached diagram are as follows: 1. Quick-release cable connector; 2. Hydrophone cable; 3. Hydrophone sensing end; 4. Flexible cable bracket; 5. Hydrophone cable U-shaped tripwire structure; 6. Subsea gate grille; 7. Grille base; 8. Subsea gate fixing buckle; Ⅰ. Above-water end; Ⅱ. Under-water end; Ⅲ. Double bottom; Ⅳ. Seawater valve box; Ⅴ. Hull plating. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] Example 1 like Figure 1 As shown, this embodiment focuses on describing the mechanical hardware architecture of an underwater equipment monitoring system based on hydrophones in complex environments, and how to deploy it on special underwater structures.

[0040] Modern large merchant ships and military vessels are equipped with seawater valve boxes (Ⅳ) at the bottom of hull plating V, serving as water intake channels. These boxes are covered by seabed gate grilles (6) to prevent the inhalation of large debris and marine life. According to shipbuilding standards, these grilles must have sufficient flow area and structural strength, but they also provide structural support points for malicious divers to damage or absorb explosives.

[0041] In the system deployment, the surface end (I) of the hydrophone is uniformly installed in the ship's safety control room or bridge, and the main transmission cable passes through the ship's internal compartments to reach the double bottom (III). At the junction of the double bottom and the seawater-filled valve box (IV), it inevitably faces enormous hydrostatic pressure and potential electrochemical corrosion. Therefore, the system is equipped with a quick-release cable connector (1) with extremely high pressure resistance and waterproof rating. This design takes into account the tendency for barnacles and other marine organisms to adhere around the seabed door, allowing for rapid disconnection and replacement of the cable section that has been submerged for a long time when the ship enters dry dock for annual maintenance.

[0042] The hydrophone cable 2, which originates from the quick-release connector, is not suspended in the cavity, but rather meanders along the anti-corrosion wall of the seawater valve box IV and is secured by the flexible cable bracket 4. The flexible bracket serves to eliminate the high-frequency mechanical vibrations transmitted to the hull from the operation of the ship's main engine, while also preventing fatigue fracture of the cable caused by vortex-induced vibrations generated when seawater flows through the valve box.

[0043] The core physical sensing area is located outside the seabed gate grille 6. The sensing cable here is specially encapsulated as a sheathed cable with extremely strong tensile strength but is highly sensitive to stress deformation. It is intentionally wrapped in a "U-shape" around the seabed gate fixing latch 8 at the top of the seawater valve box door, forming a U-shaped tripwire structure 5 for the hydrophone cable. When subjected to physical interference, the U-shaped tripwire structure is inevitably pulled, resulting in macroscopic deformation or breakage, providing a definitive physical hard interruption signal for subsequent dual-modal verification.

[0044] Example 2 Based on Example 1, this example elaborates on the optical path design mechanism of the fiber optic sensor-based implementation, especially the optical hardware compensation scheme proposed for the polarization fading problem in deep-sea environments.

[0045] In this embodiment, the acoustic and physical dual-modal sensing hydrophone device adopts an improved structure based on the interferometer principle. The upper end I contains a narrow-linewidth laser that generates highly coherent light waves. The light waves first pass through an optical circulator to avoid damage to the light source from reflected light, then enter an acousto-optic modulator for frequency shift modulation, and are amplified by an erbium-doped fiber amplifier before long-distance transmission.

[0046] After the light wave reaches the fiber optic hydrophone probe at underwater end II via the transmission optical cable, the core interference mechanism begins to operate. The probe contains an optical coupler that precisely splits the incident light into two equal beams, which enter the reference arm and the sensing arm respectively. The optical fiber of the sensing arm constitutes the aforementioned U-shaped tripwire structure 5 wrapped around the outside of the seawater valve box.

[0047] Example 3 Based on Example 1, this example provides an alternative implementation scheme based on the piezoelectric ceramic principle. This example elaborates on the specific engineering implementation of this piezoelectric architecture.

[0048] In this architecture, the core component of the underwater terminal II is replaced by a receiving array composed of multiple piezoelectric ceramic resonators. Piezoelectric ceramics can directly convert sound pressure fluctuations in seawater into weak voltage signals. To resist the strong corrosiveness of seawater and ensure lossless sound wave penetration, the piezoelectric ceramic array is entirely covered with a sound-permeable layer made of polyurethane or a special rubber material. The acoustic impedance of the sound-permeable layer is highly matched to that of seawater, thereby minimizing sound wave reflection losses at the interface.

[0049] Because the voltage signal generated underwater is extremely weak and easily attenuated by the distributed capacitance of long-distance transmission cables and affected by external electromagnetic interference, a preamplifier was designed directly behind the piezoelectric ceramic in the system. This preamplifier mainly performs impedance transformation and preliminary voltage amplification, converting the weak high-impedance signal into a strong low-impedance signal suitable for cable transmission.

[0050] The surface unit I is equipped with a low-noise power supply module that provides stable and clean DC power to the underwater preamplifier and sensor array, in order to prevent power frequency interference from the ship's electrical grid from coupling into the sensor signals. The transmitted electrical signals are filtered and gain-adjusted by a signal conditioner before entering high-speed data acquisition, completing analog-to-digital conversion, and finally being sent to the processing terminal.

[0051] In this architecture, the underwater U-shaped tripwire structure 5 differs physically from the fiber optic system. It no longer relies on optical path difference sensing but instead employs a special cable with a built-in miniature circuit breaker. The tripwire integrates a mechanical tension switch or an electromagnetic on / off circuit. When the externally applied physical pulling force exceeds a set safety threshold, or when the cable is cut, the circuit instantly breaks, directly generating a hard interruption physical alarm signal with a level flip to the high-speed data acquisition instrument. While this hard interruption mechanism is not as precise as fiber optic phase shift sensing, it has low engineering implementation costs and extremely high reliability in harsh environments.

[0052] Example 4 In one specific embodiment, taking the prevention of underwater intrusion when a ship is anchored in a port as an example, the specific operation process of the underwater equipment monitoring system and control method based on hydrophones of the present invention is as follows: Figure 4 As shown: Step S1: System operation monitoring. The shipborne processing terminal receives environmental acoustic data collected in real time from the hydrophone installed at the seawater valve box, and simultaneously receives physical tension or deformation data of the U-shaped tripwire structure of the hydrophone cable laid at the bar.

[0053] Step S2: Acoustic Warning Judgment. When an underwater intrusion target, such as a frogman or a miniature underwater vehicle, approaches, the shipborne processing terminal inputs the received acoustic data into a preset abnormal sound source identification model for feature matching. When the model identifies preset features such as frogman breathing apparatus noise, metal cutting or collision sounds, or underwater propulsion noise, a first warning signal is generated and the process proceeds to step S4; if no abnormal features are identified, the process returns to step S1.

[0054] Step S3: Physical warning judgment. The system synchronously monitors the U-shaped tripwire structure. When an underwater target attempts to damage the grille or cross the channel and physically touches the cable, the U-shaped tripwire structure experiences a sudden change in tension or deformation. The system responds and generates a second warning signal, proceeding to step S4. If no physical anomaly is detected, the system returns to step S1.

[0055] Step S4: Dual Verification Confirmation. The shipborne processing terminal determines whether the first and second warning signals are triggered simultaneously or sequentially within the set time window. If so (when the first and second warning signals are triggered simultaneously or sequentially within the set time window), the acoustic and physical systems successfully verify each other, effectively eliminating false alarms caused by a single acoustic event or marine organism contact, confirming that the seawater valve box has been intruded, generating a high-confidence confirmed intrusion alarm, and proceeding to step S5; if the verification fails, return to step S1.

[0056] Step S5: Alarm and Data Reporting. The ship's control room receives confirmed intrusion alarms and specific abnormal data in real time. Based on the ship's current location in port waters or at anchor, the ship-to-shore communication module actively pushes security status data, location information, and acoustic waveform characteristics to the receiving base station of the port security department.

[0057] Step S6: Ship-shore coordinated response. After receiving and verifying the abnormal data, the port security department system sends a forced stop or prohibition of movement command to the target vessel via the communication link; at the same time, an underwater robot is deployed to the waters where the target vessel is located, and the underwater robot is used to conduct close-range monitoring and subsequent operations on the target seawater valve box, realizing a security closed loop.

[0058] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An underwater equipment monitoring system based on hydrophones, characterized in that... include: The underwater defense zone physical structure is deployed at the double bottom of the ship and the seawater valve box, and the seawater valve box is equipped with a seabed gate grille on the outside; The acoustic and physical dual-modal sensing hydrophone device uses hydrophone cables to form a U-shaped tripwire structure on and around the seabed gate grid, which is used to simultaneously monitor underwater environmental acoustic frequency oscillation data as well as low-frequency mechanical deformation or tension data of the U-shaped tripwire structure caused by external pulling or cutting. The feature recognition terminal is connected to the sensing device for demodulating the collected data and executing dual verification logic based on acoustic feature classification and physical state change. The ship-shore collaborative communication module, connected to the feature recognition terminal, is used to broadcast alarm data to the outside world using the ship-shore network when the dual verification logic determines that it is a high-confidence intrusion event.

2. The underwater equipment monitoring system based on hydrophones according to claim 1, characterized in that... The hydrophone cable includes a consumable cable segment, which is arranged along the wall of the seawater valve box and connected to the hydrophone sensing end through a flexible cable bracket; the upper end of the consumable cable segment is connected to the double bottom through a cable quick-release connector with high-pressure waterproof performance; the U-shaped tripwire structure is wrapped in a U-shape around the bottom door fixing buckle at the top of the seawater valve box door.

3. The underwater equipment monitoring system based on hydrophones according to claim 1, characterized in that, The above-water end of the acoustic and physical dual-modal sensing hydrophone device is uniformly installed in the ship's safety control room or bridge. Its underwater end passes through the cabin penetration section inside the ship via the main transmission cable to reach the double bottom. At the junction of the double bottom and the seawater-filled seawater valve box, it is connected to the hydrophone cable arranged along the wall of the seawater valve box via the cable quick-release connector.

4. The underwater equipment monitoring system based on hydrophones according to claim 1, characterized in that, The acoustic and physical dual-modal sensing hydrophone device is an optical fiber sensor. Its above-water end includes a narrow-linewidth laser, an acousto-optic modulator, an erbium-doped fiber amplifier, and an optical circulator connected in sequence via optical paths. Its underwater end has an optical fiber hydrophone probe connected to an armored main cable. When the U-shaped tripwire structure is physically damaged, the change in its optical path difference and the phase shift and intensity attenuation of the interference optical field caused by the macrobending loss of the optical fiber serve as physical sensing trigger signals.

5. The underwater equipment monitoring system based on a hydrophone according to claim 4, characterized in that, The fiber optic hydrophone probe is positioned underwater and sealed to the armored main cable. The armored main cable passes through the ship's internal hull-through structure and reaches the double bottom. It is then connected to the optical path of the easily damaged section of the hydrophone cable via the cable quick-release connector. The narrow-linewidth laser, acousto-optic modulator, erbium-doped fiber amplifier, and optical circulator are sequentially optically connected and positioned above water.

6. The underwater equipment monitoring system based on hydrophones according to claim 1, characterized in that, The acoustic and physical dual-modal sensing hydrophone device is a piezoelectric acoustic sensor. Its underwater end includes a piezoelectric ceramic and a preamplifier that is impedance matched and directly connected to it. Its above-water end is equipped with a low-noise power supply module and a signal conditioner, a high-speed data acquisition instrument and a processing terminal connected in sequence. The U-shaped tripwire structure integrates a mechanical tension switch or an electromagnetic on / off circuit to generate a hard interruption physical alarm signal.

7. The underwater equipment monitoring system based on hydrophones according to claim 6, characterized in that, The piezoelectric ceramic array is located at the underwater end and is covered with a sound-transmitting layer that matches the acoustic impedance of seawater. The piezoelectric ceramic is directly connected to the preamplifier, which is connected to the signal conditioner at the surface end via a transmission cable. The low-noise power module provides DC power to the underwater end via a power supply cable that passes through the cabin.

8. A control method for an underwater equipment monitoring system based on a hydrophone as described in any one of claims 1-7, characterized in that, include: The S1 shipborne processing terminal receives environmental acoustic data collected in real time from hydrophones deployed at the seawater valve box, and simultaneously receives physical tension or deformation data of the U-shaped tripwire structure laid at the seabed gate grid. S2 inputs the acoustic data into a preset abnormal sound source identification model for feature matching. When frogman breathing apparatus noise, metal cutting sound or underwater propulsion noise is identified, a first warning signal is generated. S3 synchronously monitors the U-shaped tripwire structure and generates a second warning signal when it detects a sudden change in tension or deformation caused by external pulling or cutting. S4 Dual Verification Diagnosis Step: Determine whether the first warning signal and the second warning signal are triggered simultaneously or successively within a set time window. If so, perform an AND logic operation to generate a high-confidence intrusion alarm. S5 broadcasts the high-confidence intrusion alarm and abnormal data to the high-frequency channel through the ship-shore collaborative communication module in the Automatic Identification System binary dedicated application message format; After receiving and analyzing the alarm, the S6 shore-based port security platform automatically interlocks and shuts down the surrounding seabed construction operations based on the target vessel's latitude and longitude, issues a shutdown command to the berthing vessel, and deploys an underwater robot to the target seawater valve box to perform on-site verification and countermeasures.

9. The control method for the underwater equipment monitoring system based on hydrophones according to claim 8, characterized in that, The S4 dual verification step is as follows: an extremely short decision time window is established on the time axis. Only when the system synchronously or successively detects a high-confidence acoustic intrusion alarm and an abnormal physical macro-bend phase shift or open circuit alarm of the U-shaped tripwire structure, the logic fusion is executed to output a true high-confidence intrusion alarm flag that eliminates false alarms caused by a single factor.

10. The control method for the underwater equipment monitoring system based on hydrophones according to claim 8, characterized in that, When a high-confidence intrusion alarm flag is generated, the ship-shore cooperative communication module calls the binary dedicated application message of the Automatic Identification System (AIS) to broadcast an alarm data stream containing the attacked ship's identification code, precise coordinates, timestamp, and pre-programmed intrusion type to the high-frequency channel.

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