Ship intrusion detection and positioning method, device, equipment, medium and product

Abstract

The application provides a ship invasion detection and positioning method, device, equipment, medium and product, and relates to the technical field of optical fiber sensing, to solve the defects of poor accuracy of passive detection of ship invasion and target positioning around important sea routes, ports and offshore facilities, and improve the accuracy of passive detection of ship invasion and target positioning. It comprises the following steps: collecting time domain signals of multiple channels based on a distributed optical fiber sensing spiral cable, and the optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure; generating a time domain gather profile based on the time domain signals of the multiple channels, the horizontal axis of the time domain gather profile represents a channel identifier, and the vertical axis of the time domain gather profile represents a signal collection time; identifying a navigation wave feature from the time domain gather profile, and determining that an invading ship exists based on the identified triangular wake ship navigation wave; and determining position information of the invading ship based on the triangular wake ship navigation wave.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing technology, and in particular to a method, apparatus, equipment, medium, and product for detecting and locating ship intrusions. Background Technology

[0002] Currently, traditional methods for detecting maritime intrusions include radar, Automatic Identification System (AIS), electro-optical tracking, and underwater acoustic monitoring. However, radar is greatly affected by sea clutter and multipath reflections, and the false alarm rate and missed detection rate increase significantly in severe sea conditions (such as heavy rain, typhoons, and giant waves); AIS relies on active cooperation from the ship and is almost completely ineffective against silent vessels such as small boats with their transponders turned off and hostile targets; electro-optical tracking has line-of-sight limitations, and its performance deteriorates sharply at night and in foggy weather.

[0003] Therefore, the current passive detection and target location methods for vessel intrusion around important near-shore waterways, ports, and offshore facilities are relatively inaccurate. Summary of the Invention

[0004] This invention provides a method, apparatus, equipment, medium, and product for vessel intrusion detection and location, which addresses the shortcomings of existing technologies in the accuracy of passive detection and target location of vessel intrusions around important near-shore waterways, ports, and offshore facilities. It improves the accuracy of passive detection and target location of vessel intrusions around important near-shore waterways, ports, and offshore facilities.

[0005] This invention provides a method for detecting and locating ship intrusions, comprising the following steps.

[0006] The distributed optical fiber sensing spiral cable is used to collect time-domain signals from multiple channels. The optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure. Multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable, and one sensing node corresponds to one channel. Based on the time-domain signals from multiple channels, a time-domain gather profile is generated. The horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis represents the signal acquisition time. The wave characteristics of the time-domain gather profile are identified, and the presence of an intruding vessel is determined based on the identified triangular wake wave. The triangular wake wave is a waveform with the tip pointing towards the longitudinal axis and the tail extending along the transverse axis. The location information of the intruding vessel is determined based on the ship's traveling wave in the triangular wake.

[0007] According to the present invention, a method for detecting and locating ship intrusion is provided, wherein the pitch of the sensing nodes in the distributed optical fiber sensing spiral cable is greater than the pitch of other positions, and the other positions are external components of the distributed optical fiber sensing spiral cable other than the sensing nodes.

[0008] According to the present invention, a method for detecting and locating ship intrusions is provided, the method further includes: Broadband filtering is performed on the time-domain signals of multiple channels to obtain the filtered time-domain signals. The passband frequency corresponding to the broadband filtering is matched with the ship navigation noise frequency band. Broadband filtering is used to filter out marine environmental noise and system noise and extract the ship broadband noise signal.

[0009] According to the present invention, a method for detecting and locating vessel intrusion is provided, which determines the location information of an intruding vessel based on a triangular wake wave, including: Identify the apex of the triangular wake wave of the ship and project the apex vertically onto the horizontal axis to determine the target channel marker corresponding to the intersection of the projections; Based on the target channel identifier and the preset mapping relationship, the target location information corresponding to the target channel identifier is determined. The preset mapping relationship includes the mapping relationship between the channel identifier and the geographical location. The target location information was determined to be the location information of the intruding vessel.

[0010] According to the present invention, a method for detecting and locating ship intrusions is provided, the method further includes: Continuously acquire time-domain signals from multiple channels and update the time-domain gather profile. The navigation path of the intruding vessel is determined based on the movement trajectory of the ship's traveling wave in the triangular wake direction along the horizontal axis.

[0011] According to the present invention, a method for ship intrusion detection and localization is provided, which identifies the flight wave features of a time-domain gather profile, including: Energy normalization is performed on the time-domain gather profile to map the signal energy of the time-domain signal of each channel to a uniform dimension. Determine the target region where the signal energy is greater than a preset energy threshold from the time-domain gather profile; Morphological analysis of the target area is performed to determine whether the characteristics of the target area match the traveling wave of a ship in a triangular wake.

[0012] The present invention also provides a vessel intrusion detection and location device, comprising the following modules: a signal acquisition module, a signal processing module, a feature recognition module, and a location determination module; The signal acquisition module is used to acquire time-domain signals from multiple channels based on a distributed optical fiber sensing spiral cable. The optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure, and multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable, with one sensing node corresponding to one channel. The signal processing module is used to generate a time-domain gather profile based on time-domain signals from multiple channels. The horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis represents the signal acquisition time. The feature recognition module is used to identify the features of the sailing wave in the time-domain gather profile and to determine the presence of an intruding vessel based on the identified triangular wake ship sailing wave. The triangular wake ship sailing wave is a waveform with the tip pointing towards the longitudinal axis and the tail extending along the transverse axis. The position determination module is used to determine the position information of intruding vessels based on the triangular wake wave.

[0013] According to the present invention, a ship intrusion detection and location device is provided, wherein the pitch of the sensing node in the distributed optical fiber sensing spiral cable is greater than the pitch of other positions, and the other positions are external parts of the distributed optical fiber sensing spiral cable other than the sensing node.

[0014] According to the present invention, a ship intrusion detection and location device includes a signal processing module that performs broadband filtering on time-domain signals from multiple channels to obtain filtered time-domain signals. The passband frequency corresponding to the broadband filtering is matched with the ship navigation noise frequency band. The broadband filtering is used to filter out marine environmental noise and system noise, and to extract the ship broadband noise signal.

[0015] According to the present invention, a ship intrusion detection and positioning device includes a location determination module, which is specifically used for: Identify the apex of the triangular wake wave of the ship and project the apex vertically onto the horizontal axis to determine the target channel marker corresponding to the intersection of the projections; Based on the target channel identifier and the preset mapping relationship, the target location information corresponding to the target channel identifier is determined. The preset mapping relationship includes the mapping relationship between the channel identifier and the geographical location. The target location information was determined to be the location information of the intruding vessel.

[0016] According to the present invention, a ship intrusion detection and positioning device includes a signal processing module that is further used to continuously acquire time-domain signals from multiple channels and update the time-domain gather profile. The location determination module is also used to determine the navigation path of the intruding vessel based on the movement trajectory of the triangular wake wave in the horizontal direction.

[0017] According to the present invention, a vessel intrusion detection and location device includes a feature recognition module, which is specifically used for: Energy normalization is performed on the time-domain gather profile to map the signal energy of the time-domain signal of each channel to a uniform dimension. Determine the target region where the signal energy is greater than a preset energy threshold from the time-domain gather profile; Morphological analysis of the target area is performed to determine whether the characteristics of the target area match the traveling wave of a ship in a triangular wake.

[0018] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described ship intrusion detection and location methods.

[0019] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the ship intrusion detection and location methods described above.

[0020] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements any of the ship intrusion detection and location methods described above.

[0021] The present invention provides a method, apparatus, equipment, medium, and product for ship intrusion detection and location. By arranging optical fibers in a helical structure within a distributed optical fiber sensing spiral cable and uniformly distributing multiple sensing nodes, time-domain signals from multiple channels are collected based on the distributed optical fiber sensing spiral cable. In this way, the helical structure of the distributed optical fiber allows for multi-angle coupling of incident sound waves and vibrations in three-dimensional space, improving the sensitivity of signal recognition. Furthermore, based on the time-domain signals from multiple channels, a time-domain gather profile is generated to identify the characteristics of the ship's wake. Based on the identified triangular wake ship waves, the presence of an intruding vessel and its location information are determined. Thus, the time-domain gather profile allows for a direct distinction between ship wakes and clutter, enabling visualization of the spatiotemporal characteristics of marine disturbances, and the triangular wake ship waves accurately locate the position of the intruding vessel. This improves the accuracy of ship intrusion detection and location around important near-shore waterways, ports, and offshore facilities. Attached Figure Description

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

[0023] Figure 1 This is one of the flowcharts of the ship intrusion detection and location method provided by the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the distributed optical fiber sensing spiral cable provided by the present invention.

[0025] Figure 3 This is the second flowchart of the ship intrusion detection and location method provided by the present invention.

[0026] Figure 4 This is the third flowchart of the ship intrusion detection and location method provided by the present invention.

[0027] Figure 5 This is a schematic diagram of the time-domain gather cross-section provided by the present invention.

[0028] Figure 6 This is the fourth flowchart of the ship intrusion detection and location method provided by the present invention.

[0029] Figure 7 This is a schematic diagram of the structure of the ship intrusion detection and positioning device provided by the present invention.

[0030] Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] Distributed Acoustic Sensing (DAS) has been gradually introduced into the field of marine monitoring in recent years. A common practice is to lay sensing fibers along the seabed or on the fence in a straight line. The back-end demodulator collects the back Rayleigh scattering signal along the optical cable using a phase-sensitive optical time-domain reflectometry (Φ-OTDR) or phase-sensitive optical time-domain reflectometry technology to achieve distributed strain / sound pressure detection.

[0033] However, linear optical fibers have low coupling efficiency for side-incident sound waves / vibrations and poor directionality, only achieving good response in directions approximately perpendicular to the cable axis. They are less sensitive to targets gliding parallel to the cable, making them prone to missed detection. Furthermore, existing fiber optic intrusion detection algorithms often rely on frequency domain energy thresholds or simple time domain amplitude envelope discrimination, failing to fully utilize the spatiotemporal two-dimensional features generated by ship navigation (the spatiotemporal structure between the bow, hull, and wake), resulting in limited accuracy and difficulty in precisely locating intrusion nodes. Moreover, traditional hydrophone arrays are complex to deploy and maintain, costly to maintain, easily damaged by fishing nets, and lack long-term operational stability.

[0034] Therefore, radar, AIS, and photoelectric methods suffer performance degradation in harsh sea conditions, making it difficult to operate stably around the clock; conventional straight optical fibers have low coupling efficiency to marine environmental noise and insufficient signal acquisition sensitivity, making it difficult to effectively capture weak noise signals from ships; using single threshold judgment or simple energy detection is easily affected by marine environmental noise (such as waves, tides, and marine biological activity), resulting in a high false alarm rate; there is a lack of effective means to identify the characteristic waveforms of ship navigation, making it difficult to accurately distinguish ship intrusion events from other environmental disturbances in complex time-domain signals; and positioning accuracy is limited by the limitations of signal processing methods, making it difficult to achieve precise positioning of intruding ships.

[0035] Therefore, there is an urgent need for a ship intrusion detection and positioning method that can improve signal acquisition sensitivity, effectively suppress environmental noise interference, accurately identify ship navigation characteristics, and achieve precise positioning.

[0036] The following is combined with Figures 1 to 8 This invention describes a method, apparatus, equipment, medium, and product for detecting and locating ship intrusions.

[0037] This invention belongs to the interdisciplinary field of marine security monitoring and distributed optical fiber sensing technology. Specifically, it involves passive detection and target positioning technology for ship intrusion around important near-shore waterways, ports, and offshore facilities. It is mainly applied to seabed optical fiber underwater acoustic sensing signal acquisition, underwater noise feature extraction, and identification and spatial positioning of moving targets at sea.

[0038] To address the shortcomings and deficiencies of existing technologies, this invention aims to solve the problems of difficult deployment, high maintenance costs, and limited spatial resolution of traditional electronic hydrophone arrays by utilizing distributed fiber optic sensing to achieve continuous passive monitoring over large sea areas. It also addresses the limitations of existing DAS technology in the field of maritime vessel intrusion detection by proposing a detection and location method specifically for vessel intrusion scenarios. Furthermore, it overcomes the problems of existing methods relying on complex frequency / time-frequency domain feature extraction and pattern recognition, and insufficient real-time performance, by directly identifying the geometric features of ship waves in time-domain gather profiles to achieve rapid and intuitive intrusion determination. Finally, it addresses the problems of high computational complexity and difficulty in meeting real-time security early warning requirements of existing ship positioning methods by utilizing the correspondence between the projection of ship wave crests and channel positions to achieve rapid location of intrusion nodes.

[0039] Figure 1 This is one of the flowcharts illustrating the ship intrusion detection and location method provided by the present invention, such as... Figure 1 As shown, the method includes the following: Step 101: Acquire time-domain signals from multiple channels based on distributed optical fiber sensing spiral cables.

[0040] In the distributed optical fiber sensing spiral cable, the optical fibers are arranged in a spiral structure, and multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable, with one sensing node corresponding to one channel.

[0041] Step 102: Generate a time-domain gather profile based on the time-domain signals from multiple channels.

[0042] In the time-domain gather profile, the horizontal axis represents the channel identifier, and the vertical axis represents the signal acquisition time.

[0043] Step 103: Identify the sailing wave features of the time-domain gather profile and determine the presence of intruding vessels based on the identified triangular wake sailing waves.

[0044] Among them, the triangular wake wave is a waveform with its tip pointing towards the longitudinal axis and its tail extending along the transverse axis.

[0045] Step 104: Determine the location information of the intruding vessel based on the triangular wake wave.

[0046] In this embodiment of the invention, Figure 2 This is a schematic diagram of the structure of the distributed optical fiber sensing spiral cable provided by the present invention, as shown below. Figure 2 As shown, the optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure. Multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable. The pitch of the sensing nodes in the distributed optical fiber sensing spiral cable is greater than the pitch of other positions. The other positions are external to the distributed optical fiber sensing spiral cable except for the sensing nodes.

[0047] In one possible implementation, the outer surface of the distributed optical fiber sensing spiral cable adopts a metal skin structure. The metal skin structure is used to provide armor-like protection for the distributed optical fiber sensing spiral cable. The metal can be a material with sufficient structural strength, such as stainless steel, or other non-metallic materials with sufficient structural strength.

[0048] In one possible implementation, the fiber optic core of the distributed fiber optic sensing spiral cable is spirally wound around an elastic inner core. The fiber is continuously wound along a three-dimensional spiral geometry, with the spiral pitch (i.e., the helical pitch) set to 5cm~15cm. Compared to straight fiber optic cables, the spiral geometry allows the fiber to couple incident sound waves / vibrations at multiple angles in three-dimensional space, improving sensitivity by 5~10 dB or more and significantly improving directionality. The coupling sensitivity of water vibrations transmitted to the fiber is increased by more than 60%, enabling the capture of weak wake vibrations from small speedboats in shallow waters.

[0049] In one possible implementation, the distributed fiber optic sensing spiral cable can be deployed at seabed or underwater mooring locations around the protected sea area (ports, cross-sea bridges, offshore wind farms, islands and reefs, marine ranches, offshore platforms, channel boundaries, etc.). The distributed fiber optic sensing spiral cable serves as the signal acquisition front end, with the back end connected to a demodulator and processing terminal. The demodulator emits probe light into the spiral cable and acquires the time-domain signals of each channel in real time, forming multi-channel time-domain gather data.

[0050] Among them, the parameters such as the helical pitch, cable diameter, and water depth of the distributed optical fiber sensing spiral cable are designed according to the specific sea area's water depth, tide, and ocean current conditions.

[0051] Specifically, the deployment method of distributed fiber optic sensing spiral cables can be selected from the topography and water depth conditions of the protected sea area, including seabed laying, floating laying, or anchoring laying. For shallow water areas such as ports and islands, seabed laying can be used, burying the spiral cable in the seabed sediment; for deep water areas, floating laying can be used, using buoyancy devices to suspend the spiral cable at a set water depth; for areas requiring precise position control, anchoring laying can be used, fixing the spiral cable to the seabed with anchor chains.

[0052] In one possible implementation, the back-end demodulator can employ a Φ-OTDR (phase-sensitive optical time-domain reflectometer) or a distributed acoustic sensing (DAS) unit to emit coherent probe light pulses into the helical cable and collect the backscattered Rayleigh signals distributed along the optical cable. Then, signal demodulation is performed; through phase / intensity demodulation, the time-domain signals of each node position on the helical cable (corresponding to each channel along the optical cable) are obtained in real time, forming multi-channel time-domain gather data along the length of the optical cable.

[0053] Specifically, the distributed fiber optic sensing spiral cable can be composed of multiple single-mode optical fibers twisted together in a spiral manner, with a spiral pitch of 1.0m and a spiral diameter of 10cm. Multiple sensing nodes are uniformly distributed along the fiber, with a spatial resolution of 1m (i.e., the distance between two adjacent sensing nodes). The distributed fiber optic sensing unit (which can employ phase-sensitive optical time-domain reflectometry (Φ-OTDR) technology) is used to acquire the time-domain signals at each sensing node location in real time, with a sampling frequency of 10kHz, thereby obtaining the raw time-domain signal data for each channel.

[0054] In one possible implementation, after acquiring time-domain signals from multiple channels, the time-domain signals from all channels can be arranged horizontally according to channel identifiers (i.e., the horizontal axis represents the channel identifier and the corresponding sea area spatial location), with the time axis as the vertical coordinate (i.e., the vertical axis represents the signal acquisition time), to draw a two-dimensional time-domain gather profile. The waveform amplitude in the time-domain gather profile is visualized using grayscale / color gradients, meaning that the pixel grayscale / color intensity in the time-domain gather profile represents the noise signal amplitude of the corresponding channel at the corresponding time. The higher the vibration amplitude, the stronger the image color contrast.

[0055] Furthermore, the wave characteristics of the time-domain gather profile are identified, and the presence of an intruding vessel is determined based on the identified triangular wake wave. The location information of the intruding vessel is then determined based on the triangular wake wave.

[0056] It should be noted that the specific description of identifying the navigation wave characteristics and determining the location information of the intruding vessel can be found in the following embodiments, and will not be repeated here.

[0057] This invention utilizes a distributed optical fiber sensing spiral cable with an helical fiber optic cable and multiple sensing nodes evenly distributed to collect time-domain signals from multiple channels. This helical structure allows for multi-angle coupling of incident sound waves and vibrations in three-dimensional space, enhancing signal recognition sensitivity. Furthermore, a time-domain gather profile is generated based on the time-domain signals from multiple channels. This profile is used to identify ship wave characteristics, and the presence and location of intruding vessels are determined based on the identified triangular wake ship waves. Thus, the time-domain gather profile allows for a clear distinction between ship wakes and clutter, enabling visualization of the spatiotemporal characteristics of marine disturbances. The triangular wake ship waves also allow for accurate location of intruding vessels. This improves the accuracy of vessel intrusion detection and location around important near-shore waterways, ports, and offshore facilities.

[0058] Figure 3 This is the second flowchart illustrating the ship intrusion detection and location method provided by the present invention, as shown below. Figure 3 As shown, the method includes the following: Step 301: Acquire time-domain signals from multiple channels based on distributed optical fiber sensing spiral cables.

[0059] Step 302: Perform broadband filtering on the time-domain signals of multiple channels to obtain the filtered time-domain signals.

[0060] Among them, the passband frequency corresponding to the broadband filtering process is matched with the ship navigation noise frequency band. The broadband filtering process is used to filter out marine environmental noise and system noise, and extract the ship broadband noise signal.

[0061] Step 303: Generate a time-domain gather profile based on the filtered time-domain signal.

[0062] Step 304: Identify the sailing wave features of the time-domain gather profile and determine the presence of intruding vessels based on the identified triangular wake sailing waves.

[0063] Step 305: Determine the location information of the intruding vessel based on the triangular wake wave.

[0064] In one possible implementation, after acquiring time-domain signals from multiple channels, broadband bandpass filtering can be applied to the time-domain signals of each channel to reduce noise and extract the ship's broadband noise. The purpose of filtering is to suppress low-frequency marine environmental noise (such as low-frequency disturbances caused by waves and tides), suppress high-frequency electronic noise and system noise, and preserve the broadband noise signal frequency band generated by the ship during navigation (typically covering tens to thousands of Hz). By rationally designing the bandpass filter, the effective signal components related to the ship's radiated noise can be extracted, thereby improving the signal-to-noise ratio.

[0065] Specifically, since marine environmental noise is mainly concentrated in the low-frequency band (wave noise is usually below 5Hz, and tidal noise is below 0.1Hz), while electronic system noise is mainly concentrated in the high-frequency band (usually above 5000Hz), and the noise signal generated by ship navigation is broadband noise with a frequency range of approximately 10Hz to 5000Hz, a digital bandpass filter is used to filter the original time-domain signal. The passband frequency is set to 10Hz to 5000Hz, the fluctuation within the passband does not exceed ±1dB, and the stopband attenuation is not less than 40dB. This effectively filters out low-frequency marine environmental noise and high-frequency electronic noise, while retaining the ship's broadband noise signal.

[0066] Furthermore, broadband filtering can employ adaptive variable coefficient bandpass filtering, with the passband frequency range set between 5Hz and 800Hz. This can match the characteristic frequency bands of wake vibrations in various civilian and small vessels, and effectively isolate low-frequency interference from tides of 0.1 to 2Hz.

[0067] Thus, by performing broadband filtering on the time-domain signals of multiple channels, a filtered time-domain signal is obtained. This can filter out marine environmental noise and system noise, extracting only the ship's broadband noise signal, thereby improving the signal's effectiveness.

[0068] Figure 4 This is the third flowchart of the ship intrusion detection and location method provided by the present invention, as shown below. Figure 4 As shown, the above-mentioned "determining the position information of intruding vessels based on the triangular wake wave" includes the following: Step 401: Identify the tip of the triangular wake wave of the ship and project the tip vertically onto the horizontal axis to determine the target channel identifier corresponding to the intersection of the projections.

[0069] Step 402: Based on the target channel identifier and the preset mapping relationship, determine the target location information corresponding to the target channel identifier.

[0070] The preset mapping relationship includes the mapping relationship between channel identifiers and geographical locations.

[0071] Step 403: Determine the target location information as the location information of the intruding vessel.

[0072] It should be noted that when a ship sails near a distributed fiber optic sensing spiral cable, broadband noise generated by the interaction between the ship's propeller and hull and the seawater will couple into the spiral cable. Since the distance between each sensing node of the spiral cable and the ship is different, the time of signal arrival at each node is different. In the time domain gather profile, it will show a wedge-shaped or triangular energy distribution centered on a certain channel and gradually spreading to both sides, which is similar to the sailing wave shape of a triangular wake.

[0073] In one possible implementation, Figure 5 This is a schematic diagram of the time-domain gather profile provided by the present invention, as shown below. Figure 5 As shown, by identifying waveform characteristics within the time-domain gather profile in real time, if the profile only contains scattered, irregular point-like or short strip-like waveforms, it is determined to be natural ocean waves or ocean current disturbances, with no ship intrusion; if the profile shows continuous triangular waveforms (triangular wake ship waves) with the tip pointing downwards towards the time axis (vertical axis) and the tail extending along the transverse channel, it is determined that a ship has entered the protected sea area, and an intrusion warning signal is immediately output.

[0074] Furthermore, the apex of the triangular wake wave of the vessel is identified, and this apex is vertically projected onto the horizontal channel coordinate axis. The channel identifier corresponding to the intersection of the projections is the intrusion node channel. By retrieving the channel-geographical location mapping database (preset mapping relationship), the underwater geographic coordinates corresponding to this channel are output, thus completing the precise location of the intruding vessel.

[0075] It should be noted that the apex of the triangular wake wave represents the location with the highest wave energy and the most concentrated channel distribution, corresponding to the moment and position of the vessel closest to the helical cable. By projecting the channel identifier corresponding to the apex onto the distributed fiber optic sensing helical cable, the precise geographical location of the vessel intrusion can be output.

[0076] For example, suppose the distributed fiber optic sensing spiral cable is 10km long, with a spatial resolution of 1m and 10,000 sensing nodes (channels). When the tip of a triangular wake wave is projected onto channel marker 5000, the corresponding physical location on the spiral cable is 5km. By combining the spiral cable's deployment coordinates (such as GPS coordinates), the precise geographical location of the intruding vessel can be determined.

[0077] In one possible implementation, a waveform threshold can be set for the ship traveling wave in a triangular wake. When the duration of the ship traveling wave in a triangular wake is greater than a certain duration (e.g., 2s, 3s, etc.) and the number of lateral coverage channels is greater than or equal to a certain number (e.g., 3 channels or 4 channels), the instantaneous pseudo waveform caused by a single wave impact can be eliminated, thereby reducing the false alarm rate of environmental noise.

[0078] In one possible implementation, based on the triangular wake wave criterion, spectral features (such as propeller cavitation characteristic spectral lines and modulation spectral features), time-frequency features, and envelope statistical features can be further integrated to identify vessel types (small speedboats, large merchant ships, underwater vehicles, etc.) and assess threat levels.

[0079] In one possible implementation, the method further includes: continuously acquiring time-domain signals from multiple channels and updating the time-domain gather profile. The navigation path of the intruding vessel is determined based on the trajectory of the traveling wave in the triangular wake direction along the transverse axis.

[0080] Thus, after identifying the intruding vessel, the time-domain gather profile can be continuously updated to track the lateral movement trajectory of the ship's traveling wave in the triangular wake, continuously outputting the real-time movement channel position of the vessel, and realizing dynamic tracking of the intruding vessel's navigation path. When the triangular wake ship's traveling wave is not identified, time-domain signals from multiple channels can be continuously and cyclically acquired, filtered, and imaged for discrimination.

[0081] In this embodiment of the invention, the apex of the triangular wake wave of a ship is identified, and this apex is vertically projected onto the horizontal axis to determine the target channel identifier corresponding to the intersection of the projections. Then, based on the target channel identifier and a preset mapping relationship, the target location information corresponding to the target channel identifier is determined, and this target location information is identified as the location information of the intruding vessel. This allows for accurate positioning of the intruding vessel and trajectory tracking.

[0082] Figure 6This is the fourth flowchart of the ship intrusion detection and location method provided by the present invention, as shown below. Figure 6 As shown, the above-mentioned "identification of sail wave features from time-domain gather profiles" includes the following: Step 601: Perform energy normalization processing on the time-domain gather profile to map the signal energy of the time-domain signal of each channel to a uniform dimension.

[0083] Step 602: Determine the target region where the signal energy is greater than the preset energy threshold from the time-domain gather profile.

[0084] Step 603: Perform morphological analysis on the target area to determine whether the characteristics of the target area match the traveling wave of a triangular wake ship.

[0085] The preset energy threshold can be a preset proportion of the maximum energy (e.g., 30%, 40%), thereby extracting connected regions exceeding the preset energy threshold from the time-domain gather profile based on the preset energy threshold.

[0086] In one possible implementation, if the connected region is determined to be approximately symmetrically distributed in the channel direction, gradually widening along the time axis, with an overall shape of wedge or triangle, and the tip pointing to the channel position first passed by the ship, then the characteristics of the target region can be determined to match the traveling wave of the triangular wake.

[0087] In one possible implementation, deep learning models (such as CNN, Transformer, graph neural networks, etc.) can be used to automatically learn the ship intrusion characteristics and delta wake patterns in the gather profile, thereby improving the robustness of false alarms under complex sea conditions (such as swells, rainfall, and marine biological noise).

[0088] In one possible implementation, the location and trajectory obtained by passive detection can be correlated with publicly available AIS data to automatically distinguish between "compliant vessels" and "abnormal / suspicious vessels," thereby improving the efficiency of command and decision-making.

[0089] In one possible implementation, multiple distributed optical cables can be deployed to form a three-dimensional or intersecting monitoring network, achieving three-dimensional coverage and cross-positioning of the protected sea area, thereby further improving positioning accuracy and anti-masking capabilities.

[0090] In one possible implementation, optical cables can be laid simultaneously on the water surface and the seabed, utilizing the noise from surface vessels and underwater vehicles (submarines, UUVs, etc.) respectively, to expand the unified monitoring capability for both surface and underwater targets.

[0091] In one possible implementation, it can also be linked with photoelectric tracking, radar precision tracking and other systems to form a multi-source collaborative monitoring system of "distributed fiber optic triggering + photoelectric / radar precision tracking".

[0092] This invention proposes a comprehensive technical approach and system configuration for applying distributed optical fiber sensing (especially distributed optical fiber acoustic sensing based on the Φ-OTDR principle) technology to the detection and location of ship intrusions at sea. A distributed optical fiber sensing spiral cable is used as the signal acquisition front end, and the coupling sensitivity of incident acoustic / vibration signals in all directions is significantly improved through a three-dimensional spiral geometry. Broadband filtering is applied to the time-domain signals output from each channel of the distributed optical fiber sensing unit to extract broadband noise signals from ships and suppress marine background interference. A ship intrusion discrimination method based on time-domain gather profiles and the morphological characteristics of a "triangular wake" is proposed, fully utilizing the spatiotemporal structural information between the bow, hull, and wake, which differs from existing discrimination methods based on single-channel amplitude or frequency-domain energy. A method for precise intrusion point location is proposed based on the channel position corresponding to the projection of the ship's traveling wave tip, and ship trajectory tracking is achieved through the migration of the tip over time. The spiral optical fiber sensing, broadband filtering, time-domain gather profile display, automatic triangular wake discrimination, node location, and alarm output form a complete maritime intrusion detection and location technical solution, creating a closed loop.

[0093] Thus, this invention enables full-area passive continuous monitoring, with simple deployment and no blind spots. It employs submarine distributed optical fiber for entirely passive sensing, eliminating the need for submarine node power supply equipment. Continuous laying of optical cables achieves full coverage of the entire sea area, eliminating the monitoring blind spots inherent in the discrete deployment of traditional hydrophone arrays. Construction and subsequent maintenance costs are significantly reduced. Furthermore, it offers a large coverage area and long monitoring distance; a single optical fiber can achieve continuous, dense monitoring over tens of kilometers, covering the entire perimeter of the fortified sea area in a single operation. The monitoring coverage is far greater than that of traditional methods such as video, radar, and AIS.

[0094] Broadband filtering can suppress ocean clutter, significantly reducing false alarms. A broadband filtering algorithm designed for the ship noise-specific frequency band can effectively separate environmental interference signals such as waves, ocean currents, and marine life, solving the high false alarm problem caused by existing fiber optic monitoring relying solely on threshold judgment, thus significantly improving the reliability of intrusion identification. Combined with temporal gather profile visualization, it intuitively distinguishes between ship wakes and clutter, generating a unified two-dimensional gather profile map from all channels, realizing visualization of the spatiotemporal characteristics of ocean disturbances. Staff can intuitively distinguish between random clutter and ship-specific triangular wakes. With dual verification using an automatic identification algorithm, the identification accuracy is higher. Furthermore, based on precise positioning at the tip of the triangular wake, spatial continuity is achieved without breaks. Continuous spatial positioning is achieved by matching the tip of the triangular wake with the fiber optic channel number. Unlike discrete arrays that can only obtain discrete point coordinates, it can output intrusion coordinates at any position along the entire fiber optic link, resulting in good positioning continuity and higher accuracy. The entire method can operate 24 / 7 and can identify "silent" ship targets with their AIS transponders turned off, filling the blind spots of traditional AIS monitoring. Spiral cables are laid on the seabed or in water, offering strong concealment and superior resistance to damage compared to surface buoys, surface radars, and other equipment.

[0095] The ship intrusion detection and location device provided by the present invention is described below. The ship intrusion detection and location device described below can be referred to in correspondence with the ship intrusion detection and location method described above.

[0096] Figure 7 This is a schematic diagram of the structure of the ship intrusion detection and positioning device provided by the present invention, as shown below. Figure 7 As shown, the vessel intrusion detection and positioning device includes the following modules: signal acquisition module 701, signal processing module 702, feature recognition module 703, and location determination module 704; The signal acquisition module is used to acquire time-domain signals from multiple channels based on a distributed optical fiber sensing spiral cable. The optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure, and multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable, with one sensing node corresponding to one channel. The signal processing module is used to generate a time-domain gather profile based on time-domain signals from multiple channels. The horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis represents the signal acquisition time. The feature recognition module is used to identify the features of the sailing wave in the time-domain gather profile and to determine the presence of an intruding vessel based on the identified triangular wake ship sailing wave. The triangular wake ship sailing wave is a waveform with the tip pointing towards the longitudinal axis and the tail extending along the transverse axis. The position determination module is used to determine the position information of intruding vessels based on the triangular wake wave.

[0097] According to the present invention, a ship intrusion detection and location device is provided, wherein the pitch of the sensing node in the distributed optical fiber sensing spiral cable is greater than the pitch of other positions, and the other positions are external parts of the distributed optical fiber sensing spiral cable other than the sensing node.

[0098] According to the present invention, a ship intrusion detection and location device includes a signal processing module that performs broadband filtering on time-domain signals from multiple channels to obtain filtered time-domain signals. The passband frequency corresponding to the broadband filtering is matched with the ship navigation noise frequency band. The broadband filtering is used to filter out marine environmental noise and system noise, and to extract the ship broadband noise signal.

[0099] According to the present invention, a ship intrusion detection and positioning device includes a location determination module, which is specifically used for: Identify the apex of the triangular wake wave of the ship and project the apex vertically onto the horizontal axis to determine the target channel marker corresponding to the intersection of the projections; Based on the target channel identifier and the preset mapping relationship, the target location information corresponding to the target channel identifier is determined. The preset mapping relationship includes the mapping relationship between the channel identifier and the geographical location. The target location information was determined to be the location information of the intruding vessel.

[0100] According to the present invention, a ship intrusion detection and positioning device includes a signal processing module that is further used to continuously acquire time-domain signals from multiple channels and update the time-domain gather profile. The location determination module is also used to determine the navigation path of the intruding vessel based on the movement trajectory of the triangular wake wave in the horizontal direction.

[0101] According to the present invention, a vessel intrusion detection and location device includes a feature recognition module, which is specifically used for: Energy normalization is performed on the time-domain gather profile to map the signal energy of the time-domain signal of each channel to a uniform dimension. Determine the target region where the signal energy is greater than a preset energy threshold from the time-domain gather profile; Morphological analysis of the target area is performed to determine whether the characteristics of the target area match the traveling wave of a ship in a triangular wake.

[0102] Figure 8 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 8As shown, the electronic device may include: a processor 810, a communications interface 820, a memory 830, and a communications bus 840, wherein the processor 810, the communications interface 820, and the memory 830 communicate with each other through the communications bus 840. The processor 810 can call logic instructions in the memory 830 to execute a ship intrusion detection and location method. This method includes: acquiring time-domain signals from multiple channels based on a distributed optical fiber sensing spiral cable, wherein the optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure, and multiple sensing nodes are uniformly distributed in the distributed optical fiber sensing spiral cable, with each sensing node corresponding to one channel; generating a time-domain gather profile based on the time-domain signals from multiple channels, where the horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis represents the signal acquisition time; identifying the navigation wave characteristics of the time-domain gather profile, and determining the presence of an intruding ship based on the identified triangular wake ship wave, where the triangular wake ship wave is a waveform with its tip pointing towards the vertical axis and its tail extending along the horizontal axis; and determining the location information of the intruding ship based on the triangular wake ship wave.

[0103] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0104] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the ship intrusion detection and location method provided by the above methods. The method includes: acquiring time-domain signals from multiple channels based on a distributed optical fiber sensing spiral cable, wherein the optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure, and multiple sensing nodes are uniformly distributed in the distributed optical fiber sensing spiral cable, with one sensing node corresponding to one channel; generating a time-domain gather profile based on the time-domain signals from multiple channels, wherein the horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis of the time-domain gather profile represents the signal acquisition time; identifying the sailing wave characteristics of the time-domain gather profile, and determining the presence of an intruding ship based on the identified triangular wake ship sailing wave, wherein the triangular wake ship sailing wave is a waveform with its tip pointing towards the vertical axis and its tail extending along the horizontal axis; and determining the position information of the intruding ship based on the triangular wake ship sailing wave.

[0105] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the ship intrusion detection and location method provided by the above methods. The method includes: acquiring time-domain signals from multiple channels based on a distributed optical fiber sensing spiral cable, wherein the optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure, and multiple sensing nodes are uniformly distributed in the distributed optical fiber sensing spiral cable, with one sensing node corresponding to one channel; generating a time-domain gather profile based on the time-domain signals from multiple channels, wherein the horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis of the time-domain gather profile represents the signal acquisition time; identifying the navigation wave characteristics of the time-domain gather profile, and determining the presence of an intruding ship based on the identified triangular wake ship traveling wave, wherein the triangular wake ship traveling wave is a waveform with its tip pointing towards the vertical axis and its tail extending along the horizontal axis; and determining the position information of the intruding ship based on the triangular wake ship traveling wave.

[0106] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0107] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting and locating ship intrusion, characterized in that, include: The distributed optical fiber sensing spiral cable is used to collect time-domain signals from multiple channels. The optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure. Multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable, and one sensing node corresponds to one channel. Based on the time-domain signals of the multiple channels, a time-domain gather profile is generated. The horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis of the time-domain gather profile represents the signal acquisition time. The time-domain gather profile is subjected to navigation wave feature identification, and the presence of an intruding vessel is determined based on the identified triangular wake wave. The triangular wake wave is a waveform with its tip pointing towards the longitudinal axis and its tail extending along the transverse axis. Identify the tip of the triangular wake wave and project the tip vertically onto the horizontal axis to determine the target channel identifier corresponding to the intersection of the projections; Based on the target channel identifier and the preset mapping relationship, the target location information corresponding to the target channel identifier is determined, wherein the preset mapping relationship includes the mapping relationship between the channel identifier and the geographical location; The target location information is determined as the location information of the intruding vessel.

2. The method for detecting and locating ship intrusion according to claim 1, characterized in that, The pitch of the sensing nodes in the distributed optical fiber sensing spiral cable is greater than the pitch of the other positions, which are external locations in the distributed optical fiber sensing spiral cable other than the sensing nodes.

3. The method for detecting and locating ship intrusion according to claim 1, characterized in that, The method further includes: The time-domain signals of the multiple channels are subjected to broadband filtering to obtain filtered time-domain signals. The passband frequency corresponding to the broadband filtering is matched with the ship navigation noise frequency band. The broadband filtering is used to filter out marine environmental noise and system noise and extract the ship broadband noise signal.

4. The method for detecting and locating ship intrusions according to any one of claims 1-3, characterized in that, The method further includes: The time-domain signals of the multiple channels are continuously acquired, and the time-domain gather profile is updated. The navigation path of the intruding vessel is determined based on the movement trajectory of the triangular wake wave along the horizontal axis.

5. The method for detecting and locating ship intrusions according to any one of claims 1-3, characterized in that, The process of identifying the sail wave features of the time-domain gather profile includes: The time-domain gather profile is subjected to energy normalization processing to map the signal energy of the time-domain signal of each channel to a uniform dimension. Determine the target region where the signal energy is greater than a preset energy threshold from the time-domain gather profile; Morphological analysis is performed on the target region to determine whether the characteristics of the target region match the traveling wave of the triangular wake ship.

6. A vessel intrusion detection and positioning device, characterized in that, include: Signal acquisition module, signal processing module, feature recognition module, and location determination module; The signal acquisition module is used to acquire time-domain signals from multiple channels based on a distributed optical fiber sensing spiral cable. The optical fibers in the distributed optical fiber sensing spiral cable are arranged in a spiral structure, and multiple sensing nodes are evenly distributed in the distributed optical fiber sensing spiral cable, with one sensing node corresponding to one channel. The signal processing module is used to generate a time-domain gather profile based on the time-domain signals of the multiple channels. The horizontal axis of the time-domain gather profile represents the channel identifier, and the vertical axis of the time-domain gather profile represents the signal acquisition time. The feature recognition module is used to identify the sailing wave features of the time-domain gather profile and determine the presence of an intruding vessel based on the identified triangular wake ship sailing wave. The triangular wake ship sailing wave is a waveform with its tip pointing towards the longitudinal axis and its tail extending along the transverse axis. The location determination module is used for: Identify the tip of the triangular wake wave and project the tip vertically onto the horizontal axis to determine the target channel identifier corresponding to the intersection of the projections; Based on the target channel identifier and the preset mapping relationship, the target location information corresponding to the target channel identifier is determined, wherein the preset mapping relationship includes the mapping relationship between the channel identifier and the geographical location; The target location information is determined as the location information of the intruding vessel.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the ship intrusion detection and location method as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the ship intrusion detection and location method as described in any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the ship intrusion detection and location method as described in any one of claims 1 to 5.

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