JP2023072986A - Submarine structure detection system - Google Patents

Abstract

To provide a submarine structure detection system that can detect presence or absence of a submarine structure and can accurately detect presence or absence of damage to a corrosion-proof layer provided on the submarine structure.SOLUTION: A submarine structure detection system 100 detects a metal submarine structure 90 provided on a sea bed 80, or detects presence or absence of damage 6a to a corrosion-proof layer 6 provided on the submarine structure 90 and formed of metal different in an ionization tendency from the submarine structure 90, and the submarine structure detection system comprises: a potential difference sensor 1 that detects a potential difference caused by a current flowing between the submarine structure 90 and the corrosion-proof layer 6; a magnetic sensor 2 that detects a magnetism in the sea; a submarine structure detection unit 10a that detects presence or absence of the submarine structure 90 on the basis of, a magnetic signal 31 output by the magnetic sensor 2; and a damage detection unit 10b that detects the presence or absence of the damage 6a to the corrosion-proof layer 6 on the basis of, the magnetic signal 31 and an electric field signal 30 output by the potential difference sensor 1.SELECTED DRAWING: Figure 5

Description

The present invention relates to a seabed structure detection system, and more particularly to a seabed structure detection system that detects seabed structures provided on the seabed while moving a magnetic sensor along the seabed.

Conventionally, there is known a seabed structure detection system that detects a seabed structure while moving a magnetic sensor along the seabed (see Patent Document 1, for example).

The above-mentioned Patent Literature 1 discloses a magnetic exploration device (submarine structure detection system) that uses magnetism to detect submarine structures provided on the seabed while moving along the seabed. The magnetic investigation apparatus disclosed in the above-mentioned Patent Document 1 includes a set of sensors in which magnetic sensors are combined in two or more upper and lower stages. In the magnetic investigation apparatus disclosed in the above-mentioned Patent Document 1, at least one pair of sensors are arranged so as to face each other in parallel on the same plane. In addition, the magnetic exploration device disclosed in Patent Document 1 moves along the seabed by being towed by a survey ship and detects magnetism emitted from a submarine pipeline buried in the seabed. Configured to detect pipelines.

JP-A-62-148877

Here, although not disclosed in the above Patent Document 1, the submarine pipeline (submarine structure) is considered to be composed of steel pipes (iron), and the outer peripheral surface of the steel pipe is covered to prevent rusting. It is considered that a corrosion protection layer formed of a metal other than iron is provided. When the anticorrosion layer is damaged, the surface of the submarine structure is exposed at the damaged portion of the anticorrosion layer. In this case, there is a problem that corrosion of the submarine structure occurs from the exposed portion of the submarine structure. When the anticorrosion layer is damaged, current flows between the exposed damaged portion of the submarine structure and the anticorrosion layer due to the difference in ionization tendency between the metal forming the submarine structure and the anticorrosion layer. In a configuration including a magnetic sensor as in Patent Document 1, it is possible to detect a damaged portion by detecting a magnetic field caused by a current flowing between the damaged portion and the anticorrosion layer. However, noise such as geomagnetism may reduce the detection accuracy of the magnetic field caused by the current flowing between the damaged portion and the anticorrosion layer. Therefore, with the configuration disclosed in Patent Document 1, there is a problem that it is difficult to detect the presence or absence of a submarine structure and accurately detect the presence or absence of damage to the anticorrosion layer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is capable of detecting the presence or absence of a submarine structure and accurately detecting the presence or absence of damage to the anticorrosion layer provided on the submarine structure. An object of the present invention is to provide a submarine structure detection system capable of

In order to achieve the above object, a submarine structure detection system in one aspect of the present invention provides detection of a metallic submarine structure provided on the seabed and detection of a metal submarine structure provided on the submarine structure. is a submarine structure detection system that detects the presence or absence of damage to the corrosion protection layer formed by metals with different ionization tendencies, and is a potential difference sensor that detects the potential difference caused by the current flowing between the submarine structure and the corrosion protection layer. , a magnetic sensor that detects magnetism in the sea, a submarine structure detection unit that detects the presence or absence of a submarine structure based on the magnetic signal output by the magnetic sensor, and an electric field signal that is output by the magnetic signal and the potential difference sensor. and a damage detection unit that detects the presence or absence of damage to the anticorrosion layer based on.

The submarine structure detection system according to the first aspect includes a submarine structure detection unit that detects the presence or absence of a submarine structure based on the magnetic signal output by the magnetic sensor. Accordingly, the presence or absence of the submarine structure can be detected by acquiring the magnetic signal. Further, in the submarine structure detection system according to the first aspect, the magnetic signal output by the magnetic sensor and the potential difference output by the potential difference sensor that detects the potential difference caused by the current flowing between the submarine structure and the anticorrosion layer. A damage detector is provided for detecting the presence or absence of damage to the anticorrosion layer based on the electric field signal. As a result, unlike the configuration in which the presence or absence of damage to the corrosion protection layer is detected only by the magnetic signal, the magnetic signal generated due to the current flowing between the submarine structure and the corrosion protection layer and the relationship between the submarine structure and the corrosion protection layer are detected. Both the electric field signal based on the potential difference caused by the current flowing between them can detect the presence or absence of damage to the corrosion protection layer. Therefore, it is possible to detect the presence or absence of damage to the anticorrosion layer with high accuracy compared to the configuration in which the presence or absence of damage to the anticorrosion layer is detected only by the magnetic signal. As a result, it is possible to provide a submarine structure detection system capable of detecting the presence or absence of a submarine structure and accurately detecting the presence or absence of damage to the anticorrosion layer provided on the submarine structure.

1 is a diagram showing the overall configuration of a submarine structure detection system according to one embodiment; FIG. 1 is a block diagram showing the configuration of a submarine structure detection system according to one embodiment; FIG. FIG. 3 is a schematic diagram for explaining the arrangement of a potentiometric sensor and a magnetic sensor according to one embodiment; FIG. 2 is a schematic diagram for explaining a configuration for acquiring a reference magnetic signal by the seafloor structure detection system according to one embodiment; FIG. 3 is a functional block diagram for explaining a configuration in which a discrimination unit according to one embodiment detects the presence or absence of a submarine structure and the presence or absence of damage to a corrosion protection layer; FIG. 4 is a schematic diagram for explaining a configuration in which a submarine structure detection unit according to one embodiment acquires a depth position of a submarine structure. Graph (A) for explaining the reference magnetic signal, graph (B) for explaining the magnetic signal when the anticorrosion layer is damaged, and graph (C) for explaining the differential magnetic signal. It is a graph (A) for explaining the electric field signal when the anticorrosion layer is not damaged, and a graph (B) for explaining the electric field signal when the anticorrosion layer is damaged. 4 is a flow chart for explaining processing for detecting the presence or absence of a submarine structure by a submarine structure detection unit according to one embodiment. 4 is a flow chart for explaining the process of detecting whether or not the anticorrosive layer is damaged by the damage detector according to the embodiment.

Embodiments embodying the present invention will be described below with reference to the drawings.

The configuration of a submarine structure detection system 100 according to one embodiment will be described with reference to FIGS. 1 to 8. FIG.

(Configuration of seafloor structure detection device)
First, the configuration of a submarine structure detection system 100 according to one embodiment will be described with reference to FIG.

The submarine structure detection system 100 is a submarine structure detection system that detects a metallic submarine structure 90 provided on the seabed 80 . The submarine structure 90 is a pipeline provided on the submarine 80 . That is, the seabed structure detection system 100 is configured to detect the presence or absence of a pipeline provided on the seabed 80 . Further, the submarine structure detection system 100 is provided in a submarine structure 90 and detects the presence or absence of damage 6a in the anticorrosion layer 6 formed of a metal having an ionization tendency different from that of the metal forming the submarine structure 90. It is an object detection system. That is, the submarine structure detection system 100 is configured to detect the presence or absence of damage to the pipeline provided on the submarine 80 . The submarine structure 90 is made of steel (iron), for example.

The pipeline includes, for example, a steel pipe provided with an anti-corrosion layer 6 covering its outer surface to prevent rust. Anticorrosion layer 6 is made of, for example, a zinc alloy. When damage 6 a occurs in the corrosion protection layer 6 , as indicated by arrow 7 , due to the difference in ionization tendency between the metal forming the submarine structure 90 and the corrosion protection layer 6 , the damage 6 a occurs to the corrosion protection layer 6 . An electric current flows through the seawater. A pipeline is an example of a "submarine structure" in the scope of claims. In the example shown in FIG. 1, the anticorrosion layer 6 provided on the submarine structure 90 is hatched for convenience.

As shown in FIG. 1 , the submarine structure detection system 100 includes a potentiometric sensor 1 , a magnetic sensor 2 and a computer 3 . Further, in the present embodiment, the submarine structure detection system 100 includes the moving body 4 . The potential difference sensor 1 and the magnetic sensor 2 are provided on the moving body 4 . Also, the computer 3 is provided on the ship 5 .

Potentiometric sensor 1 is configured to detect a potential difference caused by current flowing between submarine structure 90 and anticorrosion layer 6 . The potentiometric sensor 1 is configured to output an electric field signal 30 (see FIG. 2) based on the potential difference caused by the current flowing in the sea between the submarine structure 90 and the anticorrosion layer 6 . In this embodiment, the potentiometric sensor 1 is configured to output the electric field signal 30 measured while being moved by the moving body 4 . Potentiometric sensor 1 includes, for example, silver/silver chloride electrodes. The position where the potential difference sensor 1 is provided on the moving body 4 will be described later.

The magnetic sensor 2 is configured to detect magnetism in the sea. The magnetic sensor 2 is also configured to output a magnetic signal 31 (see FIG. 2) based on the magnetism in the sea. The magnetic sensor 2 is provided on the moving body 4 . In this embodiment, the magnetic sensor 2 is configured to output a magnetic signal 31 measured while being moved by the moving body 4 . The magnetic sensor 2 is configured to output magnetic signals 31 in the vertical direction of the moving body 4 and in two directions perpendicular to each other in a plane perpendicular to the vertical direction. Magnetic sensor 2 includes, for example, a three-axis magnetometer.

The computer 3 is configured to detect the submarine structure 90 based on the magnetic signal 31 output from the magnetic sensor 2 . Further, the computer 3 is configured to detect the presence or absence of damage 6 a in the anticorrosion layer 6 based on the magnetic signal 31 and the electric field signal 30 output from the potentiometric sensor 1 . In this embodiment, the damage 6a of the anticorrosion layer 6 is corrosion of the anticorrosion layer 6, for example. That is, in this embodiment, the computer 3 is configured to detect whether or not the anticorrosion layer 6 is corroded. The computer 3 detects whether or not the surface of the submarine structure 90 is exposed due to the corrosion of the anticorrosion layer 6 and current (corrosion current) flows between the submarine structure 90 and the anticorrosion layer 6. , the presence or absence of damage 6a of the anticorrosion layer 6 is detected. Further, the computer 3 is configured to control the movement of the moving body 4 . Details of the configuration for detecting the presence or absence of the submarine structure 90 and the configuration for detecting the presence or absence of the damage 6a of the anticorrosion layer 6 by the computer 3 will be described later.

The moving body 4 is provided with the magnetic sensor 2 and the potential difference sensor 1, and is configured to be movable in water. In this embodiment, the moving body 4 is configured to move both the potentiometric sensor 1 and the magnetic sensor 2 integrally. In addition, the moving body 4 has a depth gauge (not shown) that acquires depth information of the moving body 4 in the sea, and a distance sensor (not shown) that acquires the distance from the moving body 4 to the measurement target. is provided. The moving body 4 is configured to be able to travel in the sea. Further, the moving body 4 is configured to be unmanned and movable in the sea. The moving body 4 is a so-called AUV (Autonomous Underwater Vehicle). A detailed configuration of the moving body 4 will be described later.

As shown in FIG. 2 , the computer 3 includes a processor 10 , a storage section 11 , a moving body information acquisition section 12 , a signal acquisition section 13 and a notification section 14 .

The processor 10 is configured to detect the presence or absence of an undersea structure 90 (see FIG. 1). The processor 10 is also configured to detect the presence or absence of damage 6a (see FIG. 1) of the anticorrosion layer 6 (see FIG. 1) provided on the submarine structure 90. FIG. The processor 10 includes, for example, a CPU (Central Processing Unit), a microprocessor, an FPGA (Field-Programmable Gate Array) configured for position determination of the submarine structure 90, and the like. The details of the configuration in which the processor 10 detects the presence or absence of the submarine structure 90 and the configuration in which the processor 10 detects the presence or absence of damage 6a to the anticorrosion layer 6 will be described later.

The storage unit 11 stores the reference magnetic signal 20 acquired in advance. The storage unit 11 is also configured to store a reference distance 21 that is the distance between the magnetic sensor 2 and the submarine structure 90 when the reference magnetic signal 20 is acquired. The storage unit 11 also stores various programs executed by the processor 10 . Storage unit 11 includes a nonvolatile storage device. Non-volatile storage devices are, for example, hard disk drives, solid state drives, and the like.

The reference magnetic signal 20 is a magnetic signal output by the magnetic sensor 2 at a position where the distance between the moving object 4 and the submarine structure 90 is the reference distance 21 . The reference distance 21 is the distance between the moving object 4 and the submarine structure 90 when the reference magnetic signal 20 is acquired. The reference magnetic signal 20 and the reference distance 21 are obtained in advance and stored in the storage unit 11 . Note that the reference magnetic signal 20 is used to detect the presence or absence of the submarine structure 90 and to detect the presence or absence of damage 6 a to the anticorrosion layer 6 . Further, the reference magnetic signal 20 and the reference distance 21 are used to acquire the depth position 25 (see FIG. 6) of the submarine structure 90 when the submarine structure 90 is present. Note that the reference distance 21 is not used for detecting the presence or absence of the damage 6a of the anticorrosion layer 6. FIG.

The mobile body information acquisition unit 12 is configured to acquire mobile body information 22 including information on the acceleration and posture of the mobile body 4 . Further, the moving body information acquiring unit 12 is configured to output the acquired moving body information 22 to the processor 10 . Mobile object information acquisition unit 12 includes, for example, a wireless communication device and an input/output interface.

The signal acquisition unit 13 is configured to acquire the electric field signal 30 from the potential difference sensor 1 provided on the moving body 4 . Also, the signal acquisition unit 13 is configured to acquire the magnetic signal 31 from the magnetic sensor 2 . The signal acquisition unit 13 is also configured to output the acquired electric field signal 30 and magnetic signal 31 to the processor 10 . Signal acquisition unit 13 includes, for example, a wireless communication device and an input/output interface.

The notification unit 14 is configured to notify a first detection result 40a (see FIG. 5), which is a detection result of the presence or absence of the submarine structure detection unit 10a. Further, the notification unit 14 is configured to notify a second detection result 40b (see FIG. 5), which is the detection result of the presence or absence of the damage 6a of the anticorrosion layer 6. As shown in FIG. Notification unit 14 is, for example, a liquid crystal display device. The notification unit 14 may be an electroluminescence display device or a projector.

The moving object 4 includes a control unit 4a, a communication unit 4b, a moving object information measuring unit 4c, and a propulsion mechanism 4d.

The control unit 4 a is configured to control the moving body 4 . Control unit 4a includes, for example, a CPU.

The communication unit 4b is configured to communicate with the computer 3 under the control of the control unit 4a. Specifically, the communication unit 4b receives from the computer 3 information about the direction in which the moving body 4 is to be moved, and outputs the electric field signal 30 output by the potential difference sensor 1 and the magnetic sensor 2 to the computer 3. It is configured to transmit magnetic signals 31 and mobile information 22 . The communication unit 4b includes, for example, a wirelessly connectable transmitting/receiving device.

The moving body information measuring unit 4c is configured to acquire information on the acceleration and posture of the moving body 4. FIG. The attitude information is a vector representing the attitude of the moving body 4 in the sea. The moving body information measuring unit 4c includes, for example, the vertical direction of the moving body 4, and an acceleration sensor in two mutually orthogonal three-axis directions in a plane orthogonal to the vertical direction.

The propulsion mechanism 4d is configured to apply a propulsion force to the moving body 4 under the control of the control section 4a. The propulsion mechanism 4d includes a propeller (not shown) and a drive source (not shown) that drives the propeller. The propulsion mechanism 4d may be a so-called screw structure in which a propeller is rotated to stir water to obtain propulsion, or a so-called water jet propulsion mechanism to obtain propulsion by jetting a high-pressure water stream backward. There may be.

<Arrangement of potentiometric sensor and magnetic sensor>
Next, the arrangement of the potential difference sensor 1 and the magnetic sensor 2 on the moving body 4 will be described with reference to FIG.

As shown in FIG. 3, the potentiometric sensor 1 includes a pair of electrodes. Specifically, the potential difference sensor 1 includes a first electrode 1a and a second electrode 1b as a pair of electrodes. Potentiometric sensor 1 is configured to detect a potential difference between first electrode 1a and second electrode 1b.

A pair of potential difference sensors 1 (first electrode 1a and second electrode 1b) are arranged in the vertical direction on the moving body 4 at a predetermined interval. The magnetic sensor 2 is provided at a position between the pair of electrodes. That is, the first electrode 1a, the second electrode 1b, and the magnetic sensor 2 are provided so as to be vertically aligned at a predetermined interval. In other words, the first electrode 1a, the second electrode 1b, and the magnetic sensor 2 are provided on the moving body 4 so that their positions in the moving direction of the moving body 4 are substantially the same.

<Acquisition of reference magnetic signal>
Next, with reference to FIG. 4, a configuration in which the submarine structure detection system 100 (see FIG. 1) acquires the reference magnetic signal 20 (see FIG. 2) will be described.

The submarine structure detection system 100 is configured to acquire the reference magnetic signal 20, for example, when the submarine structure 90 is laid. Specifically, the submarine structure detection system 100 acquires the reference magnetic signal 20 by detecting the magnetism emitted from the submarine structure 90 while moving the moving object 4 . At this time, the distance obtained by the distance sensor provided on the moving body 4 is stored as the reference distance 21 in the storage unit 11 (see FIG. 2) together with the reference magnetic signal 20 .

Further, the submarine structure detection system 100 acquires the reference magnetic signal 20 after the submarine structure 90 is laid and before the damage 6a (see FIG. 1) occurs in the anticorrosion layer 6 of the submarine structure 90.

<Detection of submarine structures and damage to anticorrosion layers>
Next, referring to FIG. 5, processor 10 detects the presence or absence of submarine structure 90 (see FIG. 1), and detects the presence or absence of damage 6a (see FIG. 1) of anticorrosion layer 6 (see FIG. 1). A configuration for detection will be described.

As shown in FIG. 5, the processor 10 includes, as functional blocks, a submarine structure detection unit 10a, a damage detection unit 10b, and a signal correction unit 10c. In other words, the processor 10 executes the program stored in the storage unit 11 to function as the submarine structure detection unit 10a, the damage detection unit 10b, and the signal correction unit 10c.

In this embodiment, the submarine structure detection system 100 acquires the electric field signal 30 and the magnetic signal 31 while moving the moving object 4 (see FIG. 1). Therefore, the electric field signal 30 and the magnetic signal 31 may change depending on the attitude of the moving body 4 . Therefore, in the present embodiment, the signal correction unit 10c is configured to correct the attitude of the moving body 4 with respect to the magnetic signal 31 and the electric field signal 30 based on the moving body information 22. FIG. Specifically, the signal correction unit 10c acquires the acceleration and attitude information of the mobile object 4 by acquiring the mobile object information 22 from the mobile object information acquisition unit 12 . Then, the signal correction unit 10c obtains a corrected electric field signal 30a by performing filtering and orthogonality correction processing on the electric field signal 30 using the obtained acceleration and orientation information of the moving body 4. FIG. That is, the signal corrector 10c corrects the electric field signal 30, thereby converting the coordinate system of the potential difference sensor 1 into the absolute coordinate system in the horizontal and vertical directions. Thereby, the signal corrector 10c can acquire the corrected electric field signals 30a in two directions perpendicular to each other in the vertical direction and the horizontal plane.

Further, the signal correction unit 10c obtains a corrected magnetic signal 31a by performing filtering and orthogonality correction processing on the magnetic signal 31 using the obtained acceleration and orientation information of the moving body 4 . That is, the signal correction unit 10c performs coordinate conversion from the coordinate system of the magnetic sensor 2 to the absolute coordinate system in the horizontal and vertical directions by performing correction processing on the magnetic signal 31 . Thereby, the signal correction unit 10c can acquire the corrected magnetic signals 31a in two directions perpendicular to each other in the vertical direction and the horizontal plane. The signal corrector 10c outputs the corrected electric field signal 30a to the damage detector 10b. The signal correction unit 10c also outputs the corrected magnetic signal 31a to the submarine structure detection unit 10a and the damage detection unit 10b.

The submarine structure detection unit 10 a is configured to detect the presence or absence of the submarine structure 90 based on the magnetic signal 31 output by the magnetic sensor 2 . In this embodiment, the submarine structure detection unit 10a detects the presence or absence of the submarine structure 90 based on the corrected magnetic signal 31a, which is the magnetic signal 31 after the posture correction has been performed by the signal correction unit 10c. is configured to

The submarine structure detection unit 10a obtains the corrected magnetic signal 31a obtained by the signal correction unit 10c. The submarine structure detection unit 10a determines the presence or absence of the submarine structure 90 (see FIG. 1) based on the amplitude 51 (see FIG. 7B) of the corrected magnetic signal 31a. Specifically, the submarine structure detection unit 10a determines that there is a submarine structure 90 when the amplitude 51 of the corrected magnetic signal 31a is greater than or equal to a predetermined magnitude. Further, the submarine structure detection unit 10a determines that there is no submarine structure 90 when the amplitude 51 of the corrected magnetic signal 31a is smaller than a predetermined magnitude.

Further, when the submarine structure detection unit 10a determines that there is a submarine structure 90, based on the reference magnetic signal 20 and the magnetic signal 31, the submarine structure detection unit 10a detects the depth position 25 of the submarine structure 90 (see FIG. 6). to get In this embodiment, the submarine structure detection unit 10 a acquires the reference magnetic signal 20 and the reference distance 21 from the storage unit 11 . The submarine structure detection unit 10a acquires the depth position 25 of the submarine structure 90 using the reference magnetic signal 20, the reference distance 21, and the correction magnetic signal 31a.

<Detection of depth position of submarine structure>
Next, a configuration in which the submarine structure detection unit 10a (see FIG. 2) acquires the depth position 25 of the submarine structure 90 will be described with reference to FIG. In this embodiment, the submarine structure detection unit 10a is configured to detect the depth position 25 of the submarine structure 90 based on the magnitude of the magnetic signal 31 (see FIG. 2). Specifically, the submarine structure detection unit 10a detects the amplitude 50 (see FIG. 7A) of the waveform of the reference magnetic signal 20 (see FIG. 2), the reference distance 21 (see FIG. 2), and the amplitude of the magnetic signal 31. The depth position 25 of the submarine structure 90 is detected based on the amplitude 51 (see FIG. 7B).

Here, it is known that the magnitude of the magnetic signal 31 is inversely proportional to the cube of the distance between the submarine structure 90 and the moving object 4 . Therefore, by comparing the amplitude 50 of the reference distance 21 and the amplitude 51 of the magnetic signal 31, it is possible to obtain the ratio of the reference distance 21 to the distance 23 between the submarine structure 90 and the moving body 4. Therefore, the distance 23 between the submarine structure 90 and the moving object 4 can be obtained.

Further, the submarine structure detection unit 10 a (see FIG. 2 ) acquires the distance 24 from the sea surface 81 to the mobile object 4 based on the depth gauge provided on the mobile object 4 . Then, the submarine structure detection unit 10a calculates the depth of the submarine structure 90 by adding the distance 23 between the submarine structure 90 and the mobile object 4 and the distance 24 from the sea surface 81 to the mobile object 4. Get position 25. That is, the depth position 25 of the submarine structure 90 is the distance from the sea surface 81 to the submarine structure 90 .

Referring to FIG. 5 again, the submarine structure detection unit 10a outputs a first detection result 40a, which is the detection result of the presence or absence of the submarine structure 90, to the notification unit 14. As shown in FIG. In this embodiment, when the submarine structure detection unit 10a determines that the submarine structure 90 is present, the submarine structure detection unit 10a sends a message to the effect that the submarine structure 90 has been detected to the notification unit 14 as the first detection result 40a. output. Further, when the submarine structure detection unit 10a determines that there is no submarine structure 90, the submarine structure detection unit 10a outputs a message to the effect that the submarine structure 90 was not detected to the notification unit 14 as the first detection result 40a. do. Note that when the submarine structure 90 is present, the submarine structure detection unit 10a also outputs the depth position 25 of the submarine structure 90 as the first detection result 40a.

The damage detector 10b is configured to detect the presence or absence of damage 6a (see FIG. 1) in the anticorrosion layer 6 (see FIG. 1) based on the magnetic signal 31 and the electric field signal 30 output by the potentiometric sensor 1. ing.

The damage detection unit 10b detects the magnetic component caused by the current flowing between the part of the submarine structure 90 where the corrosion protection layer 6 is damaged 6a and the corrosion protection layer 6, and the current component included in the electric field signal 30. Based on, the presence or absence of the damage 6a of the anticorrosion layer 6 is detected. Specifically, the damage detection unit 10b is configured to acquire the magnetic component caused by the current based on the reference magnetic signal 20 and the magnetic signal 31 . In this embodiment, the damage detector 10b obtains the corrected electric field signal 30a and the corrected magnetic signal 31a obtained by the signal corrector 10c. The damage detector 10b detects the presence or absence of the damage 6a of the anticorrosion layer 6 based on the corrected magnetic signal 31a and the corrected electric field signal 30a, which is the electric field signal 30 after the posture is corrected by the signal corrector 10c. is configured to

When the submarine structure detection unit 10a determines that there is a submarine structure 90, the damage detection unit 10b determines whether the anticorrosion layer 6 provided on the submarine structure 90 has damage 6a. Specifically, the damage detection unit 10b detects the corrected electric field signal 30a output by the signal correction unit 10c, the corrected magnetic signal 31a output by the signal correction unit 10c, and the reference magnetic signal 20 stored in the storage unit 11. The presence or absence of the damage 6a is detected based on and.

In this embodiment, the anticorrosion layer 6 is made of a metal that has an ionization tendency different from that of the submarine structure 90 . Therefore, when there is damage 6a in the anticorrosion layer 6, current flows from the damage 6a to the anticorrosion layer 6 as indicated by arrows 7 (see FIG. 1) based on the difference in ionization tendency. In this case, magnetism is generated due to the current flowing from the damage 6a to the anticorrosion layer 6. FIG. The magnetic sensor 2 (see FIG. 1) outputs a magnetic signal 31 containing the magnetism caused by the current flowing from the damage 6a to the anticorrosion layer 6. FIG.

Here, the magnetic signal 31 includes noise caused by geomagnetism and the like, in addition to the magnetic component caused by the current flowing from the damage 6a to the anticorrosion layer 6 . In the presence of noise, it is difficult to distinguish the magnetism caused by the current flowing from the damage 6a to the anticorrosion layer 6. FIG. Therefore, in the present embodiment, the damage detection unit 10b detects the damage of the anticorrosion layer 6 based on the differential magnetic signal 32 (see FIG. 7C), which is a signal obtained by subtracting the reference magnetic signal 20 from the magnetic signal 31. It is configured to detect the presence or absence of damage 6a. The damage detector 10b acquires a differential magnetic signal 32, which is the difference between the corrected magnetic signal 31a and the reference magnetic signal 20. FIG.

In this embodiment, the damage detection unit 10b detects the damage based on the first peak 60 (see FIG. 7C) of the differential magnetic signal 32 and the second peak 62 of the electric field signal 30 (see FIG. 8B). , the presence or absence of damage 6a of the anticorrosion layer 6 is detected. Specifically, the damage detection unit 10b determines whether or not the differential magnetic signal 32 includes a first peak 60 based on the magnetism caused by the current flowing from the damage 6a to the anticorrosion layer 6. 6a is determined.

Further, in the present embodiment, the damage detection unit 10b has a first acquisition position 61 (see FIG. 7C) that is the acquisition position of the first peak 60, and a second acquisition position that is the acquisition position of the second peak 62. 63 (see FIG. 8B), the position of the damage 6a of the anticorrosion layer 6 is detected. Specifically, the damage detection unit 10b acquires the first acquisition position 61 based on the time when the detection of the damage 6a was started and the moving distance of the moving body 4 when the first peak 60 was acquired. . Further, the damage detection unit 10b acquires the second acquisition position 63 based on the time when the detection of the damage 6a was started and the moving distance of the moving body 4 when the second peak 62 was acquired.

If the anticorrosive layer 6 is damaged 6a, the damage detector 10b acquires a message indicating that the anticorrosive layer 6 is damaged 6a as the second detection result 40b. Moreover, the damage detection part 10b acquires the position of the damage 6a as the 2nd detection result 40b, when the anticorrosive layer 6 has the damage 6a. Further, when the anticorrosion layer 6 is not damaged 6a, the damage detection unit 10b acquires a message indicating that the anticorrosion layer 6 is not damaged 6a as the second detection result 40b. Further, the damage detection unit 10b outputs the acquired second detection result 40b to the notification unit 14 . If the submarine structure 90 does not exist, the damage detection unit 10b does not determine whether the corrosion protection layer 6 has damage 6a, and therefore does not obtain the second detection result 40b. That is, when the submarine structure 90 does not exist, the damage detection unit 10b does not output the second detection result 40b to the notification unit 14 .

The notification unit 14 displays the first detection result 40a input from the submarine structure detection unit 10a. Moreover, the notification part 14 displays the 2nd detection result 40b with the 1st detection result 40a, when the 2nd detection result 40b is input from the damage detection part 10b.

<Each signal waveform>
Next, the magnetic signal 31 detected by the magnetic sensor 2 and the electric field signal 30 detected by the potentiometric sensor 1 will be described with reference to FIGS. 7 and 8. FIG. Note that the example shown in FIG. 7 is a conceptual diagram, and the magnetic signal 31 actually includes noise such as geomagnetism. The example shown in FIG. 8 is also a conceptual diagram, and the electric field signal 30 actually includes noise such as the potential difference in the surrounding environment.

FIG. 7A is a graph 70 showing the reference magnetic signal 20 obtained in advance and stored in the storage unit 11 (see FIG. 2). In the graph 70, the vertical axis is the magnetic force, and the horizontal axis is the moving distance of the moving body 4 (see FIG. 1).

The reference magnetic signal 20 shown in the graph 70 is the magnetic signal detected by the magnetic sensor 2 (see FIG. 1) at the reference distance 21 (see FIG. 2). That is, since the reference magnetic signal 20 is a signal obtained in a state where the anticorrosion layer 6 (see FIG. 1) is not damaged 6a (see FIG. 1), it does not include a peak caused by the damage 6a.

FIG. 7B is a graph 71 showing the corrected magnetic signal 31a output by the magnetic sensor 2 (see FIG. 1) and corrected by the signal corrector 10c (see FIG. 5). In the graph 71, the vertical axis is the magnetic force, and the horizontal axis is the moving distance of the moving body 4 (see FIG. 1). The example shown in FIG. 7B is the correction magnetic signal 31a when the anticorrosion layer 6 (see FIG. 1) has damage 6a (see FIG. 1). Therefore, the corrected magnetic signal 31a shown in FIG. 7B includes the first peak 60, which is the magnetic component caused by the current flowing from the damage 6a to the anticorrosion layer 6. As shown in FIG. The first peak 60 includes a positive first peak 60a and a negative first peak 60b. The positive first peak 60a is a peak appearing at the starting point of the current flowing from the damage 6a to the anticorrosion layer 6. As shown in FIG. Moreover, the first negative peak 60b is a peak that appears at the position of the end point of the current flowing from the damage 6a to the anticorrosion layer 6. As shown in FIG.

FIG. 7C is a graph 72 showing the differential magnetic signal 32 acquired by the submarine structure detection unit 10a (see FIG. 5). In the graph 72, the vertical axis is the magnetic force, and the horizontal axis is the moving distance of the moving body 4 (see FIG. 1). The differential magnetic signal 32 includes a first peak 60 which is the magnetic component due to the current flowing from the damage 6a (see FIG. 1) to the sacrificial layer 6 (see FIG. 1). Further, since the differential magnetic signal 32 is a signal obtained by subtracting the reference magnetic signal 20 from the corrected magnetic signal 31a (see FIG. 5), noise due to geomagnetism around the submarine structure 90 (see FIG. 1) is removed. there is That is, the differential magnetic signal 32 is a signal with a high SNR (Signal Noise Ratio) of the magnetic component (first peak 60) caused by the current flowing from the damage 6a to the anticorrosion layer 6. FIG.

FIG. 8A is a graph 73 showing the electric field signal 30b when there is no damage 6a (see FIG. 1) in the anticorrosion layer 6 (see FIG. 1). In the graph 73, the vertical axis is the magnetic force, and the horizontal axis is the moving distance of the moving body 4 (see FIG. 1). No current flows from the submarine structure 90 if there is no damage 6a. Therefore, the electric field signal 30b shown in the graph 73 is a signal that does not include a peak.

FIG. 8B shows the corrected electric field signal 30a when the anticorrosion layer 6 (see FIG. 1) has damage 6a (see FIG. 1). In the graph 74, the vertical axis is the magnetic force, and the horizontal axis is the moving distance of the moving body 4 (see FIG. 1). If there is a damage 6a, current flows from the damage 6a to the anticorrosion layer 6. FIG. Therefore, the electric field signal 30b includes a second peak 62 due to the current flowing from the damage 6a to the anticorrosion layer 6. FIG. The second peak 62 includes a positive second peak 62a and a negative second peak 62b. The positive second peak 62a is a peak appearing at the starting point of the current flowing from the damage 6a to the anticorrosion layer 6. FIG. The negative second peak 62b is a peak that appears at the end point of the current flowing from the damage 6a to the anticorrosion layer 6. FIG.

When there is damage 6a in the anticorrosion layer 6, a first peak 60 (see FIG. 7(C)) resulting from the current flowing from the damage 6a to the anticorrosion layer 6 is detected, and a second peak 62 is also detected. . Since the potentiometric sensor 1 and the magnetic sensor 2 are integrally moved by the moving body 4 (see FIG. 1), the position of the first peak 60 (first acquisition position 61 (see FIG. 7C)) and the second Based on the position of the peak 62 (second acquisition position 63), the position of the damage 6a of the anticorrosion layer 6 can be obtained.

Note that the first acquisition positions 61 include a first acquisition position 61a corresponding to the positive first peak 60a and a first acquisition position 61b corresponding to the negative first peak 60b. Therefore, the damage detection unit 10b acquires the first acquisition position 61a corresponding to the first positive peak 60a and the first acquisition position 61b corresponding to the first negative peak 60b to detect the corrosion protection layer 6 and the damage 6a ( surface of the submarine structure 90) can be obtained.

The second acquisition positions 63 also include a second acquisition position 63a corresponding to the positive second peak 62a and a second acquisition position 63b corresponding to the negative second peak 62b. Therefore, the damage detection unit 10b acquires the second acquisition position 63a corresponding to the positive second peak 62a and the second acquisition position 63b corresponding to the negative second peak 62b, thereby detecting the corrosion protection layer 6 and the damage 6a ( surface of the submarine structure 90) can be obtained.

<Detection processing of submarine structures>
Next, with reference to FIG. 9, the process of detecting the presence or absence of the submarine structure 90 by the submarine structure detection system 100 will be described.

In step 101, the submarine structure detection unit 10a (see FIG. 5) acquires the magnetic signal 31 (see FIG. 2) output by the magnetic sensor 2 (see FIG. 1). Specifically, the submarine structure detection unit 10a acquires a corrected magnetic signal 31a (see FIG. 5) corrected by the signal correction unit 10c (see FIG. 5).

At step 102, the submarine structure detection unit 10a (see FIG. 2) determines whether or not the submarine structure 90 (see FIG. 1) has been detected. Specifically, the submarine structure detection unit 10a detects the submarine structure based on whether the magnitude of the amplitude 51 (see FIG. 7B) of the corrected magnetic signal 31a is equal to or greater than a predetermined magnitude. 90 is detected. If submarine structure 90 is detected, the process proceeds to step 103 . If the submarine structure 90 has not been detected, the process proceeds to step 107 .

At step 103, the submarine structure detection unit 10a acquires a message indicating that the submarine structure 90 has been detected as the first detection result 40a (see FIG. 5).

At step 104, the submarine structure detection unit 10a acquires the reference magnetic signal 20 (see FIG. 2) stored in the storage unit 11 (see FIG. 2).

At step 105, the submarine structure detection unit 10a acquires the depth position 25 of the submarine structure 90, as shown in FIG.

In step 106, the notification unit 14 (see FIG. 2) notifies the first detection result 40a. Specifically, the reporting unit 14 reports a depth position 25 of the submarine structure 90 and a message to the effect that the submarine structure 90 has been detected. After that, the process ends.

Further, when the process proceeds from step 102 to step 107, in step 107, the submarine structure detection unit 10a acquires a message indicating that the submarine structure 90 was not detected as the first detection result 40a.

In step 108, the notification unit 14 notifies the first detection result 40a. Specifically, the reporting unit 14 reports a message to the effect that the submarine structure 90 has not been detected. After that, the process ends. The submarine structure detection unit 10a repeats the processing of steps 101 to 108 at predetermined intervals.

Next, referring to FIG. 10, submarine structure detection system 100 detects the presence or absence of damage 6a (see FIG. 1) of anticorrosion layer 6 (see FIG. 1) provided on submarine structure 90 (see FIG. 1). The detection process will be explained. The processing shown in FIG. 10 is executed when it is determined in the processing shown in FIG. 9 that the submarine structure 90 is present. 10, the processor 10 (see FIG. 2) is in a state of acquiring the magnetic signal 31 (see FIG. 2) and the reference magnetic signal 20 (see FIG. 2).

At step 200, the damage detector 10b (see FIG. 5) acquires the differential magnetic signal 32 (see FIG. 7C). Specifically, the damage detection unit 10b acquires the difference magnetic signal 32 from the difference between the corrected magnetic signal 31a (see FIG. 2) and the reference magnetic signal 20. FIG.

In step 201, the damage detector 10b acquires the position of the first peak 60 (first acquired position 61 (see FIG. 7C)). Specifically, the damage detection unit 10b acquires the first acquisition position 61 based on the moving distance of the moving body 4 when the first peak 60 is detected.

At step 202, the damage detector 10b acquires the electric field signal 30 (see FIG. 2). Specifically, the damage detector 10b acquires a corrected electric field signal 30a (see FIG. 5) corrected by the signal corrector 10c (see FIG. 5).

In step 203, the damage detection unit 10b acquires the position of the second peak 62 (second acquisition position 63 (see FIG. 8B)). Specifically, the damage detection unit 10b acquires the second acquisition position 63 based on the moving distance of the moving body 4 when the second peak 62 is detected. Either the processing of steps 200 and 201 or the processing of steps 202 and 203 may be performed first.

At step 204, the damage detector 10b determines whether or not there is a first peak 60 or a second peak 62. FIG. Specifically, the damage detector 10b determines whether the first peak 60 is detected in the differential magnetic signal 32 or whether the second peak 62 is detected in the corrected electric field signal 30a. If either the first peak 60 or the second peak 62 is detected, processing proceeds to step 205 . If both the first peak 60 and the second peak 62 are not detected, processing proceeds to step 208 .

In step 205, the damage detector 10b acquires the position of the damage 6a of the anticorrosion layer 6 based on the peak. Note that when both the first peak 60 and the second peak 62 are detected, the damage detection unit 10b detects the position of the damage 6a of the anticorrosion layer 6 based on the first acquisition position 61 and the second acquisition position 63. to get Further, when only one of the first peak 60 and the second peak 62 is detected, the damage detection unit 10b detects the position of the damage 6a of the anticorrosion layer 6 based on the acquired position of one of the peaks. get.

At step 206, the damage detector 10b acquires a message indicating that the damage 6a of the anticorrosion layer 6 has been detected as the second detection result 40b (see FIG. 5).

At step 207, the notification unit 14 (see FIG. 5) notifies the second detection result 40b.

When the process proceeds from step 204 to step 208, in step 208, the damage detector 10b acquires a message indicating that the damage 6a of the anticorrosion layer 6 was not detected as the second detection result 40b. The process then proceeds to step 207 .

That is, when the process proceeds from step 206 to step 207, in step 207, a message to the effect that the damage 6a of the anticorrosive layer 6 has been detected is notified as the second detection result 40b. Further, when the process proceeds from step 208 to step 207, in step 207, a message to the effect that the damage 6a of the anticorrosive layer 6 was not detected is notified as the second detection result 40b.

(Effect of this embodiment)
The following effects can be obtained in this embodiment.

In the present embodiment, as described above, the submarine structure detection system 100 detects the metal submarine structure 90 provided on the seabed 80 and the submarine structure 90 is provided with an ionization tendency. a submarine structure detection system for detecting the presence or absence of damage 6a in the anticorrosion layer 6 formed of different metals, and a potential difference sensor for detecting the potential difference caused by the current flowing between the submarine structure 90 and the anticorrosion layer 6 1, a magnetic sensor 2 for detecting magnetism in the sea, a submarine structure detection unit 10a for detecting the presence or absence of a submarine structure 90 based on the magnetic signal 31 output by the magnetic sensor 2, the magnetic signal 31 and the potential difference. and a damage detection unit 10b that detects the presence or absence of damage 6a in the anticorrosion layer 6 based on the electric field signal 30 output by the sensor 1 .

Accordingly, the submarine structure detection system 100 includes the submarine structure detection unit 10a that detects the presence or absence of the submarine structure 90 based on the magnetic signal 31 output by the magnetic sensor 2. Therefore, by acquiring the magnetic signal 31, The presence or absence of the submarine structure 90 can be detected. Further, the submarine structure detection system 100 detects the magnetic signal 31 output by the magnetic sensor 2 and the potential difference sensor 1 that detects the potential difference caused by the current flowing between the submarine structure 90 and the anticorrosion layer 6. A damage detection unit 10b is provided for detecting the presence or absence of damage 6a in the anticorrosion layer 6 based on the electric field signal 30. FIG. As a result, unlike the configuration in which the presence or absence of damage 6a in the anticorrosion layer 6 is detected only by the magnetic signal 31, the magnetic signal 31 generated due to the current flowing between the submarine structure 90 and the anticorrosion layer 6 and the submarine structure Both the electric field signal 30 based on the potential difference caused by the current flowing between the object 90 and the anticorrosion layer 6 can detect the presence or absence of the damage 6a of the anticorrosion layer 6 . Therefore, compared with the structure which detects the presence or absence of the damage 6a of the anticorrosion layer 6 only by the magnetic signal 31, the presence or absence of the damage 6a of the anticorrosion layer 6 can be detected accurately. As a result, a submarine structure detection system 100 capable of detecting the presence or absence of a submarine structure 90 and accurately detecting the presence or absence of damage 6a in the anticorrosion layer 6 provided on the submarine structure 90 is provided. be able to.

Further, in the above-described embodiment, the following further effects can be obtained by configuring as follows.

That is, in the present embodiment, as described above, the damage detection unit 10b detects the magnetic component caused by the current flowing between the corrosion protection layer 6 and the portion of the submarine structure 90 where the corrosion protection layer 6 is damaged 6a. and the component of the current included in the electric field signal 30, the presence or absence of the damage 6a of the anticorrosion layer 6 is detected. As a result, the damage detection unit 10b detects the magnetic component caused by the current flowing between the corrosion-resistant layer 6 and the location where the damage 6a of the corrosion-resistant layer 6 occurs, and the component of the current included in the electric field signal 30. In order to detect the presence or absence of the damage 6a of the anticorrosion layer 6, the damage 6a of the anticorrosion layer 6 is detected by using only one of the magnetic signal 31 and the electric field signal 30. Detection accuracy can be improved.

Further, in the present embodiment, as described above, the storage unit 11 that stores the reference magnetic signal 20 acquired in advance is further provided. Based on the reference magnetic signal 20 and the magnetic signal 31, the damage detector 10b It is configured to obtain the magnetic component due to the electric current. As a result, even if the magnetic signal 31 contains noise such as geomagnetism, it is possible to easily obtain the magnetic component caused by the current flowing between the corrosion protection layer 6 and the location where the damage 6a of the corrosion protection layer 6 occurs. can be done. As a result, it is possible to suppress deterioration in detection accuracy of the damage 6a of the anticorrosion layer 6 due to noise such as geomagnetism.

Further, in the present embodiment, as described above, the damage detection unit 10b detects the first peak 60 of the differential magnetic signal 32, which is a signal obtained by subtracting the reference magnetic signal 20 from the magnetic signal 31, and the electric field signal 30. Based on the second peak 62, the presence or absence of damage 6a of the anticorrosion layer 6 is detected. As a result, the presence or absence of damage 6a in the anticorrosion layer 6 can be detected based on whether the differential magnetic signal 32 includes the first peak 60 and whether the electric field signal 30 includes the second peak 62. can. As a result, the presence or absence of damage 6a in the anticorrosion layer 6 can be easily detected.

Further, in the present embodiment, as described above, the damage detection unit 10b has the first acquisition position 61, which is the acquisition position of the first peak 60, and the second acquisition position 63, which is the acquisition position of the second peak 62. Based on this, the position of the damage 6a of the anticorrosion layer 6 is detected. Accordingly, by acquiring the first acquisition position 61 and the second acquisition position 63, the position of the damage 6a of the anticorrosion layer 6 can be easily acquired.

Further, in the present embodiment, as described above, the storage unit 11 is configured to store the reference distance 21 that is the distance between the magnetic sensor 2 and the submarine structure 90 when the reference magnetic signal 20 is obtained. The submarine structure detection unit 10a detects the depth position 25 of the submarine structure 90 based on the amplitude 50 of the waveform of the reference magnetic signal 20, the reference distance 21, and the amplitude 51 of the magnetic signal 31. is configured to This makes it possible to obtain the depth position 25 of the submarine structure 90 even when the submarine structure 90 is buried in the sand of the submarine 80 and cannot be visually observed. can be obtained well.

Further, in this embodiment, as described above, the mobile body 4 provided with the magnetic sensor 2 and the potential difference sensor 1 and capable of moving in water is further provided. Thereby, the magnetic sensor 2 and the potential difference sensor 1 can be moved integrally. Therefore, when the anticorrosion layer 6 has damage 6a, the detection timing of the first peak 60 in the magnetic signal 31 and the detection timing of the second peak 62 in the electric field signal 30 are substantially equal. As a result, for example, compared to a configuration in which the magnetic sensor 2 and the potentiometric sensor 1 are moved separately, the location of the damage 6a in the anticorrosion layer 6 can be determined based on the location of the first peak 60 and the location of the second peak 62. can be easily obtained.

Further, in the present embodiment, as described above, the potential difference sensor 1 includes a pair of electrodes (the first electrode 1a and the second electrode 1b), and the pair of potential difference sensors 1 are arranged on the moving body 4 at predetermined intervals. The magnetic sensors 2 are provided so as to line up in the vertical direction, and the magnetic sensor 2 is provided at a position between a pair of electrodes. Thereby, the pair of electrodes and the magnetic sensor 2 can be arranged in a direction perpendicular to the traveling direction of the moving body 4 . Therefore, for example, when performing detection while moving the moving body 4 along the direction in which the submarine structure 90 extends, the pair of electrodes and the magnetic sensor 2 can be easily arranged at a position orthogonal to the submarine structure 90. can do. As a result, the position of the first peak 60 and the position of the second peak 62 can be made substantially equal, so the position of the damage 6a of the anticorrosion layer 6 can be obtained more easily.

Further, in the present embodiment, as described above, the moving body information acquiring unit 12 acquires the moving body information 22 including information on the acceleration and attitude of the moving body 4, and based on the moving body information 22, the magnetic signal 31 and the A signal correction unit 10c that corrects the attitude of the moving body 4 with respect to the electric field signal 30 is further provided. The damage detection unit 10b is configured to detect the presence or absence of the submarine structure 90 based on the corrected magnetic signal 31a, which is the correction magnetic signal 31a and the signal correction unit 10c. Based on the corrected electric field signal 30a, which is the electric field signal 30 later, the presence or absence of the damage 6a of the anticorrosion layer 6 is detected. As a result, the presence or absence of the submarine structure 90 and the presence or absence of damage 6 a to the anticorrosion layer 6 can be detected without correcting the posture of the moving body 4 . Therefore, unlike the configuration in which the presence or absence of the submarine structure 90 and the presence or absence of the damage 6a of the anticorrosion layer 6 are detected while correcting the attitude of the moving body 4, the submarine structure can be detected without performing attitude control of the moving body 4. It is possible to detect the presence/absence of 90 and the presence/absence of damage 6a of the anticorrosion layer 6. FIG. As a result, it is possible to improve the degree of freedom of movement of the moving body 4, so that it is possible to improve the degree of freedom in detecting the presence or absence of the submarine structure 90 and the presence or absence of damage 6a in the anticorrosion layer 6. can.

Further, in the present embodiment, as described above, the moving body 4 is provided with the magnetic sensor 2, the potential difference sensor 1, and the propulsion mechanism 4d that applies a driving force to the moving body 4, so that the moving body 4 can travel in the sea. is configured to Thereby, for example, compared with the structure which moves the mobile body 4 by towing the mobile body 4 with the ship 5, the freedom of movement of the mobile body 4 can be improved.

Further, in the present embodiment, as described above, the submarine structure 90 is a pipeline provided on the submarine 80, and the submarine structure detection unit 10a is configured to determine the presence or absence of the pipeline. The damage 6a of the anticorrosion layer 6 is corrosion of the anticorrosion layer 6, and the damage detection unit 10b is configured to detect the presence or absence of corrosion of the pipeline. Accordingly, it is possible to provide the submarine structure detection system 100 suitable for detecting the presence or absence of pipelines and detecting the presence or absence of corrosion of pipelines.

(Modification)
It should be noted that the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the above description of the embodiments, and includes all modifications (modifications) within the meaning and scope equivalent to the scope of the claims.

For example, in the above-described embodiment, the damage detection unit 10b acquires the magnetic component caused by the current based on the reference magnetic signal 20 and the magnetic signal 31, and detects the presence or absence of the damage 6a in the anticorrosion layer 6. However, the present invention is not limited to this. For example, the damage detector 10 b may be configured to detect the presence or absence of damage 6 a in the anticorrosion layer 6 without using the reference magnetic signal 20 .

Moreover, although the damage detection part 10b showed the example of the structure which acquires the difference magnetic signal 32 in the said embodiment, this invention is not limited to this. For example, the damage detection unit 10b does not need to acquire the differential magnetic signal 32. However, if the damage detection unit 10b does not acquire the differential magnetic signal 32, the detection accuracy of the presence or absence of the damage 6a of the anticorrosion layer 6 decreases due to noise such as geomagnetism. Therefore, the damage detector 10b is preferably configured to acquire the differential magnetic signal 32. FIG.

Further, in the above-described embodiment, an example of a configuration in which the submarine structure detection unit 10a acquires the depth position 25 of the submarine structure 90 has been described, but the present invention is not limited to this. For example, the submarine structure detection unit 10 a does not need to acquire the depth position 25 of the submarine structure 90 .

Further, in the above embodiment, an example in which the moving body 4 is configured to be able to travel autonomously was shown, but the present invention is not limited to this. For example, the moving body 4 may be configured to move in the sea by being towed by the vessel 5 .

Further, in the above-described embodiment, the submarine structure detection system 100 has shown an example of a configuration including the signal correction unit 10c, but the present invention is not limited to this. For example, the submarine structure detection system 100 may not include the signal corrector 10c. However, if the submarine structure detection system 100 does not include the signal correction unit 10c, the detection accuracy of the presence of the submarine structure 90 and the detection accuracy of the damage 6a of the anticorrosion layer 6 are lowered. Therefore, it is preferable that the submarine structure detection system 100 includes the signal corrector 10c.

Further, in the above-described embodiment, an example of a configuration in which the computer 3 and the mobile object 4 communicate by wireless communication has been shown, but the present invention is not limited to this. For example, the computer 3 and the mobile object 4 may be connected by wire and configured to perform wire communication.

Further, in the above-described embodiment, an example of a configuration in which the damage detection unit 10b determines that there is damage 6a in the anticorrosion layer 6 when either the first peak 60 or the second peak 62 is detected is shown. , the present invention is not limited to this. For example, the damage detector 10b may be configured to determine that the anticorrosion layer 6 has the damage 6a when both the first peak 60 and the second peak 62 are detected.

Further, in the above-described embodiment, for convenience of explanation, a flow-driven flowchart in which the control processing of the submarine structure detection unit 10a and the control processing of the damage detection unit 10b are performed in order along the processing flow is used. Although shown for the illustrated example, the invention is not so limited. In the present invention, the control processing of the submarine structure detection unit 10a and the control processing of the damage detection unit 10b may be performed by event-driven processing that executes processing on an event-by-event basis. In this case, it may be completely event-driven, or a combination of event-driven and flow-driven.

[Aspect]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are specific examples of the following aspects.

(Item 1)
Detecting a metal submarine structure provided on the seabed and detecting the presence or absence of damage to a corrosion protection layer provided on the submarine structure and formed of a metal having an ionization tendency different from that of the metal forming the submarine structure. An undersea structure detection system,
a potential difference sensor that detects a potential difference caused by a current flowing between the submarine structure and the anticorrosion layer;
A magnetic sensor that detects magnetism in the sea,
a submarine structure detection unit that detects the presence or absence of the submarine structure based on the magnetic signal output by the magnetic sensor;
a damage detection unit that detects whether or not the anticorrosion layer is damaged based on the magnetic signal and the electric field signal output by the potential difference sensor.

(Item 2)
The damage detection unit detects a magnetic component caused by the current flowing between a portion of the submarine structure where the anticorrosion layer is damaged and the anticorrosion layer, and a component of the current included in the electric field signal. The submarine structure detection system according to item 1, configured to detect the presence or absence of damage to the anticorrosion layer based on and.

(Item 3)
further comprising a storage unit for storing a pre-obtained reference magnetic signal,
The submarine structure detection system according to item 2, wherein the damage detection unit is configured to acquire the magnetic component caused by the current based on the reference magnetic signal and the magnetic signal.

(Item 4)
The damage detector detects damage to the anticorrosion layer based on a first peak of a differential magnetic signal, which is a signal obtained by subtracting the reference magnetic signal from the magnetic signal, and a second peak of the electric field signal. 4. Undersea structure detection system according to item 3, configured to detect presence or absence.

(Item 5)
The damage detection unit detects the damage position of the anticorrosion layer based on a first acquisition position that is the acquisition position of the first peak and a second acquisition position that is the acquisition position of the second peak. 5. The submarine structure detection system according to item 4, wherein:

(Item 6)
The storage unit is configured to store a reference distance, which is a distance between the magnetic sensor and the submarine structure when the reference magnetic signal is acquired,
The submarine structure detection unit is configured to detect the depth position of the submarine structure based on the amplitude of the waveform of the reference magnetic signal, the reference distance, and the amplitude of the magnetic signal. , items 3 to 5, the submarine structure detection system according to any one of items 3 to 5.

(Item 7)
7. The submarine structure detection system according to any one of items 1 to 6, further comprising a moving body provided with the magnetic sensor and the potential difference sensor and capable of moving underwater.

(Item 8)
The potentiometric sensor includes a pair of electrodes,
a pair of the potential difference sensors arranged vertically at a predetermined interval on the moving body,
The submarine structure detection system according to item 7, wherein the magnetic sensor is provided at a position between the pair of electrodes.

(Item 9)
a moving body information acquisition unit that acquires moving body information including information on the acceleration and attitude of the moving body;
a signal correction unit that corrects the posture of the moving body with respect to the magnetic signal and the electric field signal based on the moving body information;
The submarine structure detection unit is configured to detect the presence or absence of the submarine structure based on the corrected magnetic signal, which is the magnetic signal after posture correction has been performed by the signal correction unit,
The damage detection unit detects the presence or absence of damage to the anticorrosion layer based on the corrected magnetic signal and the corrected electric field signal that is the electric field signal after the posture has been corrected by the signal correction unit. A submarine structure detection system according to item 7 or 8, wherein:

(Item 10)
Any one of items 7 to 9, wherein the moving body is provided with the magnetic sensor, the potential difference sensor, and a propulsion mechanism that applies a driving force to the moving body, and is configured to be able to travel in the sea. 2. The submarine structure detection system according to item 1.

(Item 11)
The submarine structure is a pipeline provided on the seabed,
The submarine structure detection unit is configured to determine the presence or absence of the pipeline,
Damage to the anticorrosion layer is corrosion of the anticorrosion layer,
The submarine structure detection system according to any one of items 1 to 10, wherein the damage detection unit is configured to detect the presence or absence of corrosion in the pipeline.

1 potentiometric sensor 1a first electrode (pair of electrodes)
1b Second electrode (pair of electrodes)
2 magnetic sensor 4 moving body 4d propulsion mechanism 6 anticorrosion layer 6a damage 10a submarine structure detection unit 10b damage detection unit 10c signal correction unit 12 moving object information acquisition unit 20 reference magnetic signal 21 reference distance 25 depth position 30 electric field signal 30a correction Electric field signal 31 Magnetic signal 31a Correction magnetic signal 32 Difference magnetic signal 50 Amplitude of reference magnetic signal 51 Amplitude of magnetic signal 60, 60a, 60b First peak 61, 61a, 61b First acquisition position 62, 62a, 62b Second peak 63 , 63a, 63b 2nd Acquisition Location 80 Seabed 90 Seabed Structure (Pipeline)
100 seabed structure detection system

Claims (11)

Detecting a metal submarine structure provided on the seabed and detecting the presence or absence of damage to a corrosion protection layer provided on the submarine structure and formed of a metal having an ionization tendency different from that of the metal forming the submarine structure. An undersea structure detection system,
a potential difference sensor that detects a potential difference caused by a current flowing between the submarine structure and the anticorrosion layer;
A magnetic sensor that detects magnetism in the sea,
a submarine structure detection unit that detects the presence or absence of the submarine structure based on the magnetic signal output by the magnetic sensor;
a damage detection unit that detects whether or not the anticorrosion layer is damaged based on the magnetic signal and the electric field signal output by the potential difference sensor. The damage detection unit detects a magnetic component caused by the current flowing between a portion of the submarine structure where the anticorrosion layer is damaged and the anticorrosion layer, and a component of the current included in the electric field signal. The submarine structure detection system according to claim 1, configured to detect the presence or absence of damage to the anticorrosion layer based on and. further comprising a storage unit for storing a pre-obtained reference magnetic signal,
3. The submarine structure detection system according to claim 2, wherein the damage detector is configured to acquire the magnetic component caused by the current based on the reference magnetic signal and the magnetic signal. The damage detector detects damage to the anticorrosion layer based on a first peak of a differential magnetic signal, which is a signal obtained by subtracting the reference magnetic signal from the magnetic signal, and a second peak of the electric field signal. 4. The undersea structure detection system of claim 3, configured to detect presence or absence. The damage detection unit detects the damage position of the anticorrosion layer based on a first acquisition position that is the acquisition position of the first peak and a second acquisition position that is the acquisition position of the second peak. 5. The submarine structure detection system according to claim 4, wherein: The storage unit is configured to store a reference distance, which is a distance between the magnetic sensor and the submarine structure when the reference magnetic signal is acquired,
The submarine structure detection unit is configured to detect the depth position of the submarine structure based on the amplitude of the waveform of the reference magnetic signal, the reference distance, and the amplitude of the magnetic signal. The submarine structure detection system according to any one of claims 3 to 5. The seafloor structure detection system according to any one of claims 1 to 6, further comprising a moving body provided with said magnetic sensor and said potential difference sensor and capable of moving underwater. The potentiometric sensor includes a pair of electrodes,
a pair of the potential difference sensors arranged vertically at a predetermined interval on the moving body,
8. The submarine structure detection system according to claim 7, wherein the magnetic sensor is provided at a position between the pair of electrodes. a moving body information acquisition unit that acquires moving body information including information on the acceleration and attitude of the moving body;
a signal correction unit that corrects the posture of the moving body with respect to the magnetic signal and the electric field signal based on the moving body information;
The submarine structure detection unit is configured to detect the presence or absence of the submarine structure based on the corrected magnetic signal, which is the magnetic signal after posture correction has been performed by the signal correction unit,
The damage detection unit detects the presence or absence of damage to the anticorrosion layer based on the corrected magnetic signal and the corrected electric field signal that is the electric field signal after the posture has been corrected by the signal correction unit. 9. The submarine structure detection system according to claim 7 or 8, wherein 10. The movable body is provided with the magnetic sensor, the potential difference sensor, and a propulsion mechanism that applies a propulsive force to the movable body, and is configured to be able to travel in the sea. 1. The submarine structure detection system according to 1. The submarine structure is a pipeline provided on the seabed,
The submarine structure detection unit is configured to determine the presence or absence of the pipeline,
Damage to the anticorrosion layer is corrosion of the anticorrosion layer,
The submarine structure detection system according to any one of claims 1 to 10, wherein the damage detector is configured to detect the presence or absence of corrosion in the pipeline.

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