Ocean bottom magnetic survey equipment

Abstract

A seabed magnetic exploration device capable of suppressing the difference in distance from each magnetic sensor to the seabed. [Solution] This is an underwater magnetic exploration device that explores dangerous objects on the seabed F by measuring with multiple magnetic sensors 12-21 fixed at intervals in a width direction W perpendicular to the direction of movement T of a frame body 11 that moves underwater. The device is equipped with multiple transmitters and receivers fixed to different locations in the width direction of the frame body 11, each of which emits sound waves toward the seabed F and receives reflected waves, distance derivation means that derives the distance from each transmitter and receiver to the seabed F based on the time difference between the emission of the sound wave by each transmitter and receiver and the reception of the reflected wave, and tilt adjustment means 25, 26, 27, 28 that adjust the tilt of the frame body 11 in the width direction.

Description

[Technical Field]

[0001] The present invention relates to a marine magnetic survey device for detecting dangerous objects on the seabed. [Background technology]

[0002] As described in Patent Documents 1 and 2, in areas where there is a possibility that dangerous objects such as unexploded bombs and mines may exist on the seabed, marine exploration is carried out to ensure the safety of marine construction work and ship navigation. In conventional marine exploration using magnetic sensors, a barge towing method involves towing a barge 102, which has a frame 101 suspended from it, to which multiple magnetic sensors 100 are fixed, by a tugboat 103, so that the frame 101 is moved through the sea in a substantially horizontal position, as shown in Figures 6(A) and 6(B).

[0003] The multiple magnetic sensors 100 are spaced apart in a direction (hereinafter referred to as the "width direction") perpendicular to the traveling direction of the frame body 101. Since detection of dangerous objects is performed from the seabed (ocean bottom surface) to a predetermined depth, the frame body 101 needs to move underwater while keeping the distance to the seabed within a predetermined range (for example, 1 m or less).

[0004] In this regard, the direction of sound wave transmission of the echo sounder 104 attached to the barge 102 is adjusted so as to measure the distance from the echo sounder 104 to the frame body 101 and the distance from the echo sounder 104 to the seabed. Since the distance from the frame body 101 to the seabed can be detected based on measurements by the echo sounder 104, an operator operates a winch on the barge 102 to raise or lower the frame body 101 in accordance with the detection results, thereby adjusting the distance from the frame body 101 to the seabed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-332995 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-345077 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although the frame body 101 has a certain length or more in the width direction (for example, a length of 8 m), the frame body 101 is generally placed horizontally in the sea. Therefore, for example, if the seabed is inclined in the width direction of the frame body 101, there was a problem that the distance from the magnetic sensor 100 to the seabed differs depending on the magnetic sensor 100.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide an ocean bottom magnetic exploration device that can reduce the difference in distance from each magnetic sensor to the seabed. [Means for solving the problem]

[0008] The seabed magnetic exploration device of the present invention, which is in line with the above-mentioned objectives, is a seabed magnetic exploration device that explores dangerous objects on the seabed by measurements from a plurality of magnetic sensors fixed at intervals in the width direction perpendicular to the direction of movement of a frame body that moves underwater, and is equipped with a plurality of transmitters and receivers fixed at different locations in the width direction of the frame body, each of which emits sound waves toward the seabed and receives reflected waves, distance derivation means that derives the distance from each transmitter and receiver to the seabed based on the time difference between the emission of the sound wave by each transmitter and receiver and the reception of the reflected wave, and tilt adjustment means that adjusts the tilt of the frame body in the width direction. [Effects of the Invention]

[0009] The seabed magnetic exploration device of the present invention comprises a plurality of transducers fixed to different locations across the width of a frame body, each of which transmits sound waves towards the seabed and receives reflected waves, a distance deriving means for deriving the distance from each transducer to the seabed based on the time difference between the transmission of sound waves by each transducer and the reception of reflected waves, and an inclination adjusting means for adjusting the inclination across the width of the frame body, thereby making it possible to reduce the difference in distance from each magnetic sensor to the seabed. [Brief explanation of the drawings]

[0010] [Figure 1]1 is an explanatory diagram of a marine magnetic exploration device according to an embodiment of the present invention; [Figure 2] (A) and (B) are explanatory diagrams of the frame body. [Figure 3] FIG. 2 is an explanatory diagram showing connections of a signal control unit. [Figure 4] FIG. 3 is an explanatory diagram of data processing by a signal control unit. [Figure 5] 10 is an explanatory diagram showing a state in which the frame body is inclined in the width direction of the frame body. FIG. [Figure 6] (A) and (B) are explanatory diagrams of the conventional barge-towed marine survey method. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, embodiments of the present invention will be described with reference to the accompanying drawings to facilitate understanding of the present invention. As shown in Figures 1, 2(A) and 2(B), a seafloor magnetic exploration device 10 according to one embodiment of the present invention comprises a frame body 11 that moves (advances) underwater, and is an apparatus that explores dangerous objects on the seafloor F by measurements using a plurality of magnetic sensors 12 to 21 fixed to the frame body 11 at intervals in a width direction W perpendicular to the direction of movement T of the frame body 11. This will be explained in detail below.

[0012] In this embodiment, the seabed magnetic exploration device 10 is used together with a tugboat 22 and a barge 23, as shown in Figure 1. The tugboat 22 tows the barge 23 with a towing rope 24 that connects the tugboat 22 and the barge 23. Note that although the seabed magnetic exploration device 10 is an apparatus used for barge-towed marine exploration, the seabed magnetic exploration device 10 (i.e., the present invention) can also be applied to self-propelled marine exploration by changing the design.

[0013] As shown in FIGS. 1 and 2(A), the frame 11 is connected to the other ends of wires 27 and 28, one end of which is fixed to winches 25 and 26 attached to a barge 23, respectively. The outer edge of the frame body 11 is rectangular and long in the width direction W, and the other end of the wire 27 is connected to one side of the frame body 11 in the width direction W (the left side in this embodiment), and the other end of the wire 28 is connected to the other side of the frame body 11 in the width direction W (the right side in this embodiment).

[0014] A towing rope 29 is connected to the front side of the frame body 11 in the traveling direction T, connecting the frame body 11 to the tugboat 22. The frame body 11 is connected to winches 25, 26 via wires 27, 28 and suspended from the barge 23, and is pulled by the tugboat 22 via the towing rope 29 to move in the traveling direction T underwater. The winches 25 and 26 each have an operation unit (such as a handle, button, or touch panel) (not shown) that is manually operated.

[0015] The winch 25 raises or lowers one side of the frame body 11 in the width direction W by winding up or down the wire 27 in response to an operation on the operation part of the winch 25. The winch 26 raises or lowers the other side of the frame body 11 in the width direction W by winding up or down the wire 28 in response to an operation on the operation part of the winch 26. The inclination of the frame body 11 in the width direction W and the distance of the frame body 11 from the sea surface (vertical position) can be adjusted by the winches 25, 26. In this embodiment, the winches 25, 26 and the wires 27, 28 mainly constitute an inclination adjustment means for adjusting the inclination of the frame body 11 in the width direction.

[0016] 2(A) and 2(B), a plurality of (five in this embodiment) long magnetic sensor probes 30 to 34 are fixed to the frame 11 at different positions in the width direction W of the frame 11. The magnetic sensor probes 30 to 34 are arranged parallel to one another and aligned along the traveling direction T. The magnetic sensor probe 30 has magnetic sensors 12 and 13 on the front and rear sides in the direction of travel T, the magnetic sensor probe 31 has magnetic sensors 14 and 15 on the front and rear sides in the direction of travel T, the magnetic sensor probe 32 has magnetic sensors 16 and 17 on the front and rear sides in the direction of travel T, the magnetic sensor probe 33 has magnetic sensors 18 and 19 on the front and rear sides in the direction of travel T, and the magnetic sensor probe 34 has magnetic sensors 20 and 21 on the front and rear sides in the direction of travel T.

[0017] Therefore, the magnetic sensors 12, 14, 16, 18, and 20 are arranged at different positions in the width direction W of the frame 11, and the magnetic sensors 13, 15, 17, 19, and 21 are arranged at different positions in the width direction W of the frame 11. As shown in Figures 2(A) and 3, the magnetic sensors 12 to 21 are each connected to a signal control unit 35 fixed to the frame 11. It goes without saying that the magnetic sensor probes 30 to 34, the signal control unit 35, and the like fixed to the frame 11 are designed to be waterproof.

[0018] The magnetic sensors 12 to 21 each measure a magnetic field (magnetic field), output the measurement value (hereinafter also referred to as "magnetic field measurement value") as analog data, and transmit it to a signal control unit 35. As shown in Fig. 3, the signal control unit 35 is equipped with an A / D converter 36 that converts the analog data of the magnetic field measurement value of the magnetic sensors 12 to 21 into digital data, and a multiplexer 38 that processes the digital data output from the A / D converter 36 so that it can be transmitted via a single transmission path (signal line) 37. The multiplexer 38 is connected via the transmission path 37 to a data processing unit 39 installed on the barge 23.

[0019] 3, the A / D converter 36 (signal control unit 35) is shown as being connected one-to-one to the magnetic sensor probe 30, but in reality, the A / D converter 36 is connected one-to-one to each of the magnetic sensors 12 and 13 so that magnetic field measurement values ​​are transmitted independently from the magnetic sensors 12 and 13 to the A / D converter 36. This also applies to the connections between the A / D converter 36 and each of the magnetic sensor probes 31, 32, 33, and 34.

[0020] The A / D converter 36 receives in parallel the analog data of the magnetic field measurement values ​​output from the magnetic sensors 12 to 21 and converts each of them into digital data. The multiplexer 38 acquires the digital data of the magnetic field measurement values ​​of the magnetic sensors 12 to 21 (digital data of 10 channels) from the A / D converter 36 at approximately the same timing, and performs processing to arrange each of the digital data in series on the time axis with a time lag as shown in Fig. 4 (i.e., performs parallel-to-serial conversion), thereby making it possible to transmit the digital data of the 10 channels to a data processing unit 39 via a single transmission path (signal line) 37.

[0021] Therefore, in this embodiment, the signal control unit 35 performs parallel-to-serial conversion on the measurement values ​​of each of the multiple magnetic sensors 12 to 21 received in parallel, and transmits them via a single transmission path 37 to a data processing unit 39 installed on a barge 23, which is an example of a ship.

[0022] 2(A) and 2(B), echo sounders 40 and 41 for measuring the distance to the seabed F are fixed to the frame body 11 at different positions in the width direction W of the frame body 11. In this embodiment, the echo sounders 40 and 41 are located on the left side (one side) and the right side (the other side) respectively with respect to the center of the width direction W of the frame body 11, and the positions of the echo sounders 40 and 41 in the traveling direction T of the frame body 11 are the same (substantially the same).

[0023] 3, the echo sounder 40 has a transducer 42 that transmits acoustic waves toward the seabed F and receives the waves reflected by the seabed F, and a calculation unit 43 that derives the distance from the transducer 42 (echo sounder 40) to the seabed F based on the time difference between the transmission of the acoustic waves by the transducer 42 and the reception of the reflected waves. The echo sounder 41 also has a transducer 44 equivalent to the transducer 42 and a calculation unit 45 equivalent to the calculation unit 43, and measures the distance from the transducer 44 (echo sounder 41) to the seabed F.

[0024] In this embodiment, the distance derivation means for deriving the distance from each transducer 42, 44 to the seabed F is configured to include calculation units 43, 45, but the distance derivation means may also be a single calculation circuit connected to the transducers 42, 44. Here, the echo sounders 40, 41 are each connected to the signal control unit 35, and the signal control unit 35 is capable of receiving data from the echo sounders 40, 41. In this embodiment, the echo sounders 40, 41 transmit digital data of the distance from the transducer 42 to the seabed F, and digital data of the distance from the transducer 44 to the seabed F, respectively, to the multiplexer 38.

[0025] The multiplexer 38 (i.e., the signal control unit 35) receives the digital data (i.e., the distance from each of the transducers 42, 44 to the seabed F, derived and output by the distance derivation means) from the acoustic sounders 40, 41, respectively, and, as shown in Figure 4, arranges this data in series along the time axis (i.e., performs serial-parallel conversion) and transmits it to the data processing unit 39 via the transmission path 37, together with the digital data of the measurement values ​​of each of the multiple magnetic sensors 12 to 21.

[0026] The data processing unit 39 can acquire and output the distances (the results derived by the distance derivation means) from each of the transducers 42, 44 to the seabed F transmitted by the multiplexer 38. The output of the results derived by the distance derivation means output to a device such as a screen, printer, or recorder connected to the data processing unit 39. The worker on the barge 23 can check the distances from each of the transducers 42, 44 to the seabed F from the output of the data processing unit 39.

[0027] As explained so far, in this embodiment, data communication from the frame 11 to the barge 23 regarding the measurement values ​​of each of the magnetic sensors 12 to 21 and the distances from each of the transducers 42, 44 to the seabed F is performed via a single transmission line 37. Because the cable having the transmission line connecting the frame 11 and the barge 23 experiences resistance from seawater when the frame 11 is submerged in the sea, minimizing the number of transmission lines facilitates the routing of the transmission lines (for example, extracting the transmission line from the sea).

[0028] In addition, the reason why the acoustic sounders 40, 41 are fixed to different positions in the width direction W of the frame body 11 is so that the worker on the barge 23 can operate the operating parts of the winches 25, 26 while checking how the seabed F below the frame body 11 is inclined relative to the width direction W of the frame body 11 based on the measurement values ​​of each acoustic sounder 40, 41, and thereby maintain the distance from each part of the frame body 11 to the seabed F within a specified range (hereinafter, this is also referred to as "this effect").

[0029] For example, as shown in Figure 5, if the frame body 11 is placed in an area where the seabed F slopes downward from one side of the width direction W of the frame body 11 (the right side in Figure 5, but actually the left side) to the other side of the width direction W of the frame body 11 (the left side in Figure 5, but actually the right side), the slope of the seabed F can be confirmed from the measurements of each of the acoustic sounders 40, 41, and an operator on the barge 23 can tilt the frame body 11 by operating the winches 25, 26 so that the one side of the width direction W of the frame body 11 is positioned higher than the other side of the width direction W.

[0030] In order to achieve this effect, it is only necessary to fix the transducers 42 and 44 to different locations in the width direction W of the frame body 11, and it is not necessary to arrange the entire echo sounder 40 and the entire echo sounder 41 at different locations in the width direction W of the frame body 11. Furthermore, in order to achieve this effect, it is only necessary to provide the operating unit of the tilt adjustment means on the barge 23, which is an example of a vessel that suspends the frame body 11, and it is not necessary to provide the entire tilt adjustment means on the barge 23 (for example, part of the winch or a part other than the operating unit may be arranged below the barge 23).

[0031] The number of transducers fixed to different positions in the width direction W of the frame body 11 may be two or more, and for example, three such transducers may be provided. To achieve this effect, it is sufficient to place the transducers at different positions in the width direction W of the frame body 11, and it is not necessary to place the transducers on one side and the other side of the width direction W based on the center of the width direction W of the frame body 11. However, from the viewpoint of stably achieving this effect, it is preferable to place one or more transducers on each side of the width direction W based on the center of the width direction W of the frame body 11.

[0032] 3, a position detection means 46 is connected to the data processing unit 39, which detects the current position using a satellite positioning system. In this embodiment, the position detection means 46 is fixed on the barge 23. Since the frame 11 moves together with the tugboat 22 and the barge 23 while positioned approximately directly below the barge 23, in this embodiment the position detected by the position detection means 46 is used as the position of the frame 11.

[0033] The data processing unit 39 acquires the position information of the frame 11 detected by the position detection means 46 (derived by a satellite positioning system) from the position detection means 46, correlates (links) the measurement values ​​of each of the magnetic sensors 12 to 21 with the position information of the frame 11 at the time the measurement values ​​of each of the magnetic sensors 12 to 21 were measured, and outputs the correlated values ​​to a device such as a screen connected to the data processing unit 39. This design eliminates the need to re-correlate the measurement values ​​of each of the magnetic sensors 12 to 21 with the position information of the frame 11, and makes it possible to efficiently identify the location where the possibility of the presence of a hazardous object on the seabed F has been detected.

[0034] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and all changes in conditions that do not depart from the gist of the present invention are within the scope of application of the present invention. For example, the data processing unit does not need to acquire the position information of the frame body. Furthermore, the measurement values ​​output from the multiple magnetic sensors may be sent to the data processing unit without parallel-to-serial conversion. This also applies to the distance from the transducer to the seabed.

[0035] The winch may be automatically controlled based on the measured distance from the transducer to the seabed to adjust the vertical position and inclination of the frame body. The tilt adjustment means is not limited to one having a winch. [Explanation of symbols]

[0036] 10: Seabed magnetic survey device, 11: Frame, 12-21: Magnetic sensors, 22: Tugboat, 23: Barge, 24: Towing rope, 25, 26: Winch, 27, 28: Wire, 29: Towing rope, 30-34: Magnetic sensor probe, 35: Signal control unit, 36: A / D converter, 37: Transmission line, 38: Multiplexer, 39: Data processing unit, 40, 41: Echo sounder, 42: Transmitter / receiver, 43: Calculation unit, 44: Transmitter / receiver, 45: Calculation unit, 46: Position detection means, F: Seabed, T: Direction of travel, W: Width direction

Claims

1. A marine magnetic exploration device that explores dangerous objects on the seabed by measuring with a plurality of magnetic sensors fixed to a frame that moves underwater at intervals in a width direction perpendicular to the moving direction of the frame, a plurality of transducers fixed to different locations in the width direction of the frame, each of which transmits a sound wave toward the seabed and receives a reflected wave; distance calculation means for calculating the distance from each of the transducers to the seabed based on the time difference between the transmission of the sound wave from each transducer and the reception of the reflected wave; and an inclination adjustment means for adjusting the inclination of the frame body in the width direction.

2. 2. The seafloor magnetic exploration device according to claim 1, further comprising a data processing unit that acquires the measurement values ​​of each of the magnetic sensors and the position information of the frame body derived by a satellite positioning system, and associates the measurement values ​​of each of the magnetic sensors with the position information of the frame body at the time the measurement values ​​of each of the magnetic sensors were measured.

3. 2. The marine magnetic exploration device according to claim 1, further comprising a signal control unit attached to the frame that converts the measurement values ​​output from the plurality of magnetic sensors and received in parallel into parallel-serial values ​​and transmits the converted values ​​to a data processing unit provided on the ship via a single transmission line.

4. 4. The marine magnetic exploration device according to claim 3, wherein the signal control unit also receives the distance from each of the transducers to the seabed derived and output by the distance derivation means, converts the received distance together with the measurement values ​​of each of the plurality of magnetic sensors into parallel-to-serial data, and transmits the converted data to the data processing unit via the transmission path.

5. the tilt adjustment means has an operation unit that is manually operated, 2. The marine magnetic exploration device according to claim 1, wherein a data processing unit that acquires and outputs the results derived by the distance deriving means and the operation unit are provided on a ship that suspends the frame.

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