Underwater passive sonar monitoring system based on unmanned aerial vehicle

Abstract

The invention provides an underwater passive sonar monitoring system based on an unmanned aerial vehicle. The passive sonar network monitoring system comprises a plurality of unmanned aerial vehicles distributed underwater and a sonar monitoring module for sonar monitoring underwater, the fixing module is used for matching and fixing the sonar monitoring module and the unmanned aerial vehicle; and the control station is arranged on the water and is used for analyzing and processing sound wave signals obtained by monitoring of the sonar monitoring module. The control station disclosed by the invention realizes efficient and accurate underwater sound source monitoring and analysis by receiving and filtering various sound wave signals, extracting a target frequency spectrum band by utilizing Fourier transform, analyzing the signals in detail to determine the type of a sound source, summarizing position information and monitoring time of different sensors, splicing the monitoring time and generating a moving track.

Description

Technical Field

[0001] The present invention relates to the technical field of marine sonar monitoring systems, and particularly to an underwater passive sonar monitoring system based on an unmanned aerial vehicle (UAV). Background Art

[0002] Sonar is an electronic device that utilizes the propagation characteristics of sound waves underwater to complete underwater detection and communication tasks through electro-acoustic conversion and information processing. It has two types: active and passive, and belongs to the category of acoustic positioning. Sonar is an electronic device that uses underwater sound waves to detect, locate, and communicate with underwater targets, and is the most widely used and important device in underwater acoustics. An underwater UAV refers to a UAV system that can operate autonomously underwater and perform tasks. They are usually equipped with sensors, cameras, robotic arms, etc., and can perform various tasks underwater, such as seabed exploration, underwater terrain mapping, and target search. The collective operation of underwater UAVs can improve the monitoring efficiency and coverage. A passive sonar network consists of multiple passive sonar nodes distributed in the ocean, which monitor the marine environment and underwater targets by receiving sounds in the water.

[0003] This experimental team has long browsed and studied a large amount of relevant recorded materials on the related technologies of marine sonar, and at the same time relied on relevant resources and conducted a large number of relevant experiments. After a large number of searches, it was found that the existing technologies such as CN116879905B, CN110865379B, CN117135732B, and CN106886015B disclosed in the prior art, such as a wake-up system based on a submersible device disclosed in the prior art, which relates to the technical field of ocean engineering. Among them, the system includes: an electromagnetic wave ringing wake-up module for receiving a cruise radio signal with a set frequency sent by a pre-programmed watercraft and waking up the first submersible device in response to the received cruise radio signal; a passive sonar wake-up module for receiving a hull sonar signal sent by the first ship and waking up the first submersible device in response to the received hull sonar signal; the passive sonar wake-up module is also used for receiving a towed sonar signal sent by a carrier platform and waking up the first submersible device in response to the received towed sonar signal; an anchoring module connected to the first submersible device for anchoring the first submersible device on the seabed. This application solves the technical problem of low wake-up efficiency of submersible devices.

[0004] In order to solve the problems such as low efficiency in identifying and tracking underwater sound sources that are prevalent in this field, the present invention is made. Summary of the Invention

[0005] The object of the present invention is to propose an underwater passive sonar monitoring system based on an unmanned aerial vehicle (UAV) in view of the current deficiencies in this field.

[0006] To overcome the deficiencies of the prior art, the present invention adopts the following technical solutions:

[0007] An underwater passive sonar monitoring system based on unmanned aerial vehicles (UAVs), the underwater passive sonar monitoring system comprising a plurality of UAVs distributed underwater, a sonar monitoring module for sonar monitoring of the underwater environment, a fixing module for adaptively fixing the sonar monitoring module to the UAVs, and a control station disposed on the water surface for analyzing and processing the acoustic signal obtained by monitoring the sonar monitoring module.

[0008] Among them, the UAVs, the sonar monitoring module and the control station are connected by communication technology signals. The UAVs include a positioning system integrated with GPS, INS, acoustic positioning, visual positioning and depth sensors.

[0009] A plurality of UAVs are respectively used for deploying the sonar monitoring module underwater and retrieving the sonar monitoring module located underwater.

[0010] The sonar monitoring module includes a plurality of monitoring units. Each monitoring unit respectively includes a plate-shaped housing, sonar sensors arranged in a matrix on the top wall of the housing, a counterweight fixed to the bottom of the housing, a locator arranged in the housing, and a memory for storing the monitoring data of the sonar sensors. The housing is of a sealed waterproof structure, and the interior of the housing is an airtight cavity.

[0011] Further, the underwater area is evenly divided into a plurality of operation areas, and each operation area has at least one UAV and a plurality of monitoring units.

[0012] The sonar sensors continuously receive sound signals from the underwater environment, and all the received sound signals are recorded and stored in the memory, waiting to be further transmitted to the UAVs.

[0013] The UAVs move underwater and periodically batch-transmit the monitoring data of all the monitoring units in the same operation area in sequence.

[0014] The UAVs regularly float to the water surface to send the monitoring data to the control station.

[0015] Further, the fixing module includes a permanent magnet fixed in the housing, and an adsorption unit fixed on the body of the UAV for generating an adsorption magnetic force on the permanent magnet to adsorb and fix the housing.

[0016] Further, the adsorption unit includes an airtight box body, an electromagnetic coil installed in the box body, a controller for controlling the magnitude of the current of the electromagnetic coil to control the electromagnetic adsorption strength of the electromagnetic coil on the permanent magnet, and a locking member for fixing the airtight box body on the UAV.

[0017] Further, the operation content of the drone for placing the monitoring unit includes:

[0018] The drone determines its current position through its own positioning system, and moves to the designated monitoring unit placement area according to the predetermined operation area division method and the instructions issued by the control station.

[0019] After reaching the designated position, the drone releases the magnetic adsorption on the monitoring unit through the adsorption unit in its fixing module, so that the monitoring unit descends to the underwater target position under the action of gravity.

[0020] After the monitoring unit reaches the underwater target position, it performs position calibration through the internal locator to ensure that the monitoring unit is stably and accurately arranged at the predetermined position and starts sonar monitoring.

[0021] Further, the operation content of the drone for retrieving the underwater monitoring unit includes:

[0022] The drone maintains regular contact with each monitoring unit through communication technology, receives the status data of the monitoring unit, including the power supply and the integrity data of the monitoring data. When the drone receives that a certain monitoring unit has insufficient power or incomplete monitoring data, it immediately records the position of the monitoring unit and notifies the control station.

[0023] The drone moves to the position of the faulty monitoring unit according to the recorded position and the instructions of the control station. The adsorption unit of the drone is activated, and a magnetic force is generated by controlling the current of the electromagnetic coil to adsorb and fix the faulty monitoring unit to the drone body. The drone drives the monitoring unit to gradually float to the water surface to bring the faulty monitoring unit back to the ground for maintenance or power supply replacement.

[0024] Further, the control station implements the following operation steps:

[0025] S101: Receive the acoustic signals received by the drone. The acoustic signals include acoustic waves from different sound sources, and the different sound sources include ships, marine organisms, and natural sounds.

[0026] S102: Filter the monitoring signals using a filter.

[0027] S103: Convert the filtered time-domain acoustic signal to a frequency-domain signal using Fourier transform, and then extract the frequency spectrum segment within the preset frequency range [Fre1, Fre2] from the frequency-domain signal as the target signal.

[0028] S104: Analyze the extracted target signals to determine the sound source type corresponding to each target signal.

[0029] S105: Combine the position information and monitoring time of the same sound source received from different sonar sensors.

[0030] Perform row summarization to form comprehensive sound source information.

[0031] S106: Continuously splice the monitoring time, and based on the position changes of the sonar sensors in the continuous monitoring time, further extract and generate the movement trajectory of the sound source within the continuous monitoring time.

[0032] The beneficial effects achieved by the present invention are as follows:

[0033] 1. The passive sonar network monitoring unit of the present invention has the advantages of flexible deployment, efficient recovery, wide coverage, real-time monitoring and data transmission, high degree of automation, reasonable structural design, accurate positioning, energy-saving and high efficiency, fast fault response, and reduction of labor costs, making it an efficient, flexible, and reliable underwater monitoring solution suitable for various application scenarios such as environmental monitoring, resource exploration, and security monitoring.

[0034] 2. The control station of the present invention realizes efficient and accurate underwater sound source monitoring and analysis by receiving and filtering various acoustic signals, extracting the target frequency spectrum segment using Fourier transform, analyzing the signals in detail to determine the sound source type, summarizing the position information and monitoring time of different sensors, splicing the monitoring time, and generating the movement trajectory.

[0035] 3. The present invention traverses the target signal to extract the maximum peak value and spectrum features, calculates the total energy, mean value of frequency distribution, discrete distribution, centroid value, shape features, energy normalization, and energy distribution feature values, and combines the pre-collected multi-type sound source samples for comprehensive eigenvalue matching, realizing efficient and accurate underwater sound source identification and classification, thereby ensuring the reliability, accuracy, and real-time response ability of the monitoring system. Description of the Drawings

[0036] The present invention can be further understood from the following description in conjunction with the drawings. The components in the drawings are not necessarily drawn to scale, but the emphasis is on showing the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0037] Figure 1 It is a modular schematic diagram of the passive sonar network monitoring system using an underwater drone swarm of the present invention.

[0038] Figure 2 It is a schematic diagram of the operation process of the control station of the present invention.

[0039] Figure 3 It is a schematic diagram of the establishment process of the sample library of the present invention. Detailed Embodiments

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with its embodiments. It should be noted that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present case. For those skilled in the art, after referring to the following detailed description, other systems, methods and / or features of this embodiment will become obvious. And the terms used to describe the positional relationship in the drawings are only for illustrative purposes and cannot be construed as a limitation on this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0041] Embodiment 1: In combination with attached Figure 1 and attached Figure 2 and attached Figure 3 , this embodiment constructs an underwater passive sonar monitoring system based on unmanned aerial vehicles. The underwater passive sonar monitoring system includes a number of unmanned aerial vehicles distributed underwater, a sonar monitoring module for sonar monitoring of the underwater, a fixing module for adapting and fixing the sonar monitoring module to the unmanned aerial vehicle, and a control station arranged on the water surface for analyzing and processing the acoustic wave signals obtained by the sonar monitoring module.

[0042] Among them, the unmanned aerial vehicle, the sonar monitoring module and the control station are connected by communication technology signals. The unmanned aerial vehicle includes a positioning system integrated with GPS, INS, acoustic positioning, visual positioning and depth sensors.

[0043] A number of unmanned aerial vehicles are respectively used to deploy the sonar monitoring module underwater and recover the sonar monitoring module located underwater.

[0044] The sonar monitoring module includes a number of monitoring units. Each monitoring unit respectively includes a plate-shaped housing, sonar sensors arranged in a matrix on the top wall of the housing, a counterweight fixed to the bottom of the housing, a locator arranged in the housing, and a storage for storing the monitoring data of the sonar sensors. And the housing is of a sealed waterproof structure, and the interior of the housing is an airtight cavity.

[0045] The underwater area is evenly divided into a number of working areas. Each working area has at least one unmanned aerial vehicle and a number of monitoring units.

[0046] The sonar sensors continuously receive sound signals from the underwater environment, and all the sound signals received by the sonar sensors are recorded and stored in the memory, waiting to be further transmitted to the unmanned aerial vehicle.

[0047] The unmanned aerial vehicle moves underwater and periodically batch-transmits the monitoring data of all monitoring units in the same working area in sequence.

[0048] The unmanned aerial vehicle regularly floats to the water surface to send the monitoring data to the control station.

[0049] The fixed module includes a permanent magnet fixed inside the housing, and an adsorption unit fixed on the airframe of the drone and used to generate an adsorption magnetic force on the permanent magnet to adsorb and fix the housing.

[0050] The adsorption unit includes an airtight box body, an electromagnetic coil installed inside the box body, a controller used to control the magnitude of the current of the electromagnetic coil to control the electromagnetic adsorption intensity of the electromagnetic coil on the permanent magnet, and a locking member for fixing the airtight box body on the drone.

[0051] The operation content of the drone placing the monitoring unit:

[0052] The drone determines its current position through its own positioning system, and moves to the designated monitoring unit placement area according to the predetermined operation area division method and the instructions issued by the control station.

[0053] After reaching the designated position, the drone releases the magnetic adsorption on the monitoring unit through the adsorption unit in its fixed module, so that the monitoring unit descends to the underwater target position under the action of gravity.

[0054] After the monitoring unit reaches the underwater target position, it performs position calibration through the internal locator to ensure that the monitoring unit is stably and accurately arranged at the predetermined position and starts sonar monitoring.

[0055] The operation content of the drone retrieving the underwater monitoring unit:

[0056] The drone maintains regular contact with each monitoring unit through communication technology and receives the status data of the monitoring unit, including the power supply power and the integrity data of the monitoring data. When the drone receives that a certain monitoring unit has insufficient power or incomplete monitoring data, it immediately records the position of the monitoring unit and notifies the control station.

[0057] The drone moves to the position where the faulty monitoring unit is located according to the recorded position and the instructions of the control station. The adsorption unit of the drone is activated, and a magnetic force is generated by controlling the current of the electromagnetic coil to adsorb and fix the faulty monitoring unit to the airframe of the drone. The drone drives the monitoring unit to gradually float to the water surface to bring the faulty monitoring unit back to the ground for maintenance or power supply replacement.

[0058] The passive sonar network monitoring unit of the present invention has the advantages of flexible deployment, efficient recovery, wide coverage, real-time monitoring and data transmission, high degree of automation, reasonable structure design, precise positioning, energy saving and high efficiency, fast fault response and reduction of labor costs, making it an efficient, flexible and reliable underwater monitoring solution suitable for various application scenarios such as environmental monitoring, resource exploration and safety monitoring.

[0059] Embodiment 2: Combined with the attached Figure 1, appendices Figure 2 , and appendices Figure 3 , in addition to the content included in the above embodiments, it is further that the control station implements the following operation steps:

[0060] S101: Receive the acoustic wave signals received by the unmanned aerial vehicle. The acoustic wave signals include acoustic waves from different sound sources, and the different sound sources include ships, marine organisms, and natural sounds.

[0061] S102: Filter the monitoring signals using a filter.

[0062] S103: Use Fourier transform to convert the filtered time-domain acoustic wave signals into frequency-domain signals, and then extract the spectral segment within the preset frequency range [Fre1, Fre2] from the frequency-domain signals as the target signals.

[0063] S104: Analyze the extracted target signals to determine the sound source types corresponding to each target signal.

[0064] S105: Summarize the position information and monitoring time of the same sound source received from different sonar sensors

[0065] to form comprehensive sound source information.

[0066] S106: Continuously splice the monitoring time, and further extract and generate the movement trajectory of the sound source during the continuous monitoring time according to the position changes of the sonar sensors during the continuous monitoring time.

[0067] The control station of the present invention realizes efficient and accurate underwater sound source monitoring and analysis by receiving and filtering various acoustic wave signals, using Fourier transform to extract the target spectral segment, analyzing the signals in detail to determine the sound source types, summarizing the position information and monitoring time of different sensors, splicing the monitoring time, and generating the movement trajectory.

[0068] Embodiment 3: Combining appendices Figure 1 , appendices Figure 2 , and appendices Figure 3 , in addition to the content included in the above embodiments, it is further that, in step S104, the method for analyzing the extracted target signals to determine the sound source types corresponding to the extracted target signals is as follows:

[0069] S1041: Traverse the target signals to obtain the frequency value Fmax corresponding to the maximum peak point in the spectral segment of the target signals. Amax is the amplitude value of the signal at the frequency point Fmax of the target signals.

[0070] S1042: Calculate the total energy Ena in the target frequencies:

[0071]

[0072] Among them, Fre represents the independent variable of the spectrum in the target signal, X(Fre) represents the signal amplitude at the frequency Fre, Fre ∈ [Fre1, Fre2], and |X(Fre)| represents the absolute value of the signal amplitude of the frequency Fre in the target signal;

[0073] S1043: Calculate the mean value of the frequency distribution Favg:

[0074]

[0075] S1044: Obtain the eigenvalue of the frequency discrete distribution Disp of the target signal:

[0076]

[0077] S1045: Obtain the centroid value Cent of the spectrum of the target signal:

[0078]

[0079] S1046: Obtain the eigenvalue Sv of the spectrum shape of the target signal:

[0080]

[0081] S1047: Calculate the energy normalization value EFR:

[0082]

[0083] S1048: Calculate the eigenvalue Han for reflecting the energy distribution of the signal spectrum:

[0084]

[0085] lnX(Fre) represents the natural logarithm value of the signal amplitude corresponding to the frequency Fre,

[0086] S1049: Calculate the comprehensive eigenvalue Fcp of the target signal:

[0087]

[0088] A1 is the weight value of log(Fmax), and the value range of A1 is 0.05 - 0.1, A2 is the weight value of and the value range of A2 is 0.1 - 0.15, A3 is the weight value of Disp, and the value range of A3 is 0.15 - 0.25, A4 is the weight value of Cent, and the value range of A4 is 0.15 - 0.2,

[0089] A5 is The weight value of, and the value range of A5 is 0.2 - 0.3,

[0090] A6 is the weight value of ln(Han + 1), and the value range of A6 is 0.1 - 0.2,

[0091] And A1 + A2 + A3 + A4 + A5 + A6 = 1,

[0092] S1049: Input the Fcp value into the sample library, and determine the sound source in the sample library that matches Fcp as the sound source of the target signal;

[0093] Among them, the sample library is stored in the control station, and the establishment of the sample library is as follows:

[0094] S201: Collect sound samples of different types of sound sources in advance, and different types of sound sources at least include the sounds of ships, marine organisms, and nature, and calculate the Fcp of each sound sample,

[0095] S202: Through a large number of repeated experimental trainings, thereby training and obtaining the Fcp value range of each type of sound source,

[0096] S203: Mark and store the sound source type and the value range to obtain the sample library,

[0097] The present invention traverses the target signal to extract the maximum peak value and spectral features, calculates the total energy, frequency distribution mean value, discrete distribution, centroid value, shape features, energy normalization, and energy distribution feature values, and combines the pre - collected multi - type sound source samples for comprehensive eigenvalue matching, realizing efficient and accurate underwater sound source recognition and classification, thereby ensuring the reliability, accuracy, and real - time response ability of the monitoring system.

[0098] Although the present invention has been described above with reference to various embodiments, it should be understood that many changes and modifications can be made without departing from the scope of the present invention. That is to say, the methods, systems, and devices discussed above are examples. Various configurations can be appropriately omitted, replaced, or various processes or components can be added. For example, in an alternative configuration, the method can be executed in an order different from the described order, and / or various components can be added, omitted, and / or combined. Moreover, the features described with respect to certain configurations can be combined in various other configurations, such as different aspects and elements of the configuration can be combined in a similar manner. In addition, as technology develops, the elements therein can be updated, that is, many elements are examples and do not limit the scope of the present disclosure or the claims. And it should be understood that after reading the content recorded in the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. An underwater passive sonar monitoring system based on a drone, characterized in that: The underwater passive sonar monitoring system includes a plurality of UAVs distributed underwater, a sonar monitoring module for performing sonar monitoring underwater, a fixing module for adapting and fixing the sonar monitoring module to the UAV, and a control station arranged above water for analyzing and processing the sound wave signals monitored by the sonar monitoring module. Among them, the drone, sonar monitoring module and control station are connected through communication technology signals. The drone includes a positioning system that is integrated with GPS, INS, acoustic positioning, visual positioning and depth sensors. Several drones are used to drop the sonar monitoring module underwater and to recover the sonar monitoring module underwater. The sonar monitoring module includes a plurality of monitoring units, each of which includes a shell with a plate-like structure, sonar sensors distributed in a matrix on the top wall of the shell, a counterweight fixed to the bottom of the shell, a positioner arranged in the shell, and a storage device for storing the monitoring data of the sonar sensor. The shell is a sealed and waterproof structure, and the interior of the shell is an airtight cavity.

2. The underwater passive sonar monitoring system according to claim 1, characterized in that: The underwater area is evenly divided into several operation areas, each of which has at least one drone and several monitoring units. The sonar sensor continuously receives sound signals from the underwater environment, and all sound signals received by the sonar sensor are recorded and stored in the memory, waiting to be further transmitted to the drone. The drone moves underwater and periodically transmits the monitoring data of all monitoring units in the same operation area in batches. The drone regularly rises to the surface to send monitoring data to the control station.

3. The underwater passive sonar monitoring system according to claim 2, characterized in that: The fixing module includes a permanent magnet fixed in the shell, and an adsorption unit fixed on the body of the drone and used to generate an adsorption magnetic force on the permanent magnet and thereby adsorb and fix the shell.

4. The underwater passive sonar monitoring system according to claim 3, characterized in that: The adsorption unit includes an airtight box, an electromagnetic coil installed in the box, a controller for controlling the current of the electromagnetic coil to control the electromagnetic adsorption strength of the electromagnetic coil to the permanent magnet, and a locking member for fixing the airtight box to the drone.

5. The underwater passive sonar monitoring system according to claim 4, characterized in that: The operation contents of placing the monitoring unit by drone include: The drone determines its current position through its own positioning system, and moves to the designated monitoring unit placement area according to the predetermined operation area division method and the instructions issued by the control station. After reaching the designated location, the drone releases the magnetic adsorption of the monitoring unit through the adsorption unit in its fixed module, allowing the monitoring unit to descend to the underwater target location through gravity. After the monitoring unit reaches the underwater target position, it performs position calibration through the internal locator to ensure that the monitoring unit is stably and accurately placed at the predetermined position, and then starts sonar monitoring.

6. The underwater passive sonar monitoring system according to claim 5, characterized in that: The operation of the drone to recover the underwater monitoring unit includes: The drone maintains regular contact with each monitoring unit through communication technology and receives the status data of the monitoring unit, including power supply and integrity data of the monitoring data. When the drone receives a message that a monitoring unit is short of power or the monitoring data is incomplete, it immediately records the location of the monitoring unit and notifies the control station. The UAV moves to the location of the faulty monitoring unit according to the recorded location of the work area and the instructions of the control station. The adsorption unit of the UAV is activated, and the magnetic force is generated by controlling the current of the electromagnetic coil to adsorb and fix the faulty monitoring unit to the UAV body. The UAV drives the monitoring unit to gradually float to the surface of the water, so as to bring the faulty monitoring unit back to the ground for maintenance or replacement of the power supply.

7. The underwater passive sonar monitoring system according to claim 6, characterized in that: The control station implements the following operating steps: S101: receiving a sound wave signal received by a drone, the sound wave signal including sound waves from different sound sources, the different sound sources including ships, marine life and natural sounds, S102: Filter the monitoring signal using a filter. S103: converting the filtered time-domain sound wave signal into a frequency-domain signal by Fourier transform, and then extracting a frequency spectrum segment within a preset frequency range [Fre1, Fre2] from the frequency-domain signal as a target signal; S104: Analyze the extracted target signals to determine the sound source type corresponding to each target signal. S105: Summarize the location information and monitoring time of the same sound source received from different sonar sensors to form comprehensive sound source information. S106: Continuously splicing the monitoring time, and further extracting and generating the movement trajectory of the sound source during the continuous monitoring time according to the position change of the sonar sensor during the continuous monitoring time.

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