JP2015177395A - Underwater investigation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater investigation device which is available even for an underwater structure of complicated structure and, even if a communication path includes an aerial portion and an underwater portion, capable of performing communication by relaying both the portions.SOLUTION: The underwater investigation device includes: an investigation part 19 which includes an imaging portion and captures a video image using the imaging portion in the water; an underwater repeater 18 which wirelessly communicates with the investigation part 19 in the water; a control part 14 which is installed in the air and controls the investigation part 19; an aerial communicator 15 which is installed in the air and connected to the control part 14; a phase conversion repeater 17 which includes an aerial antenna installed in the air and an underwater antenna at least partially installed in the water, wirelessly communicates with the aerial communicator 15 in the air and wirelessly communicates with the underwater repeater 18 in the water. The underwater repeater 18 relays the communication between the investigation part 19 and the phase conversion repeater 17 in the water. Communication rates are different for the communication between the aerial communicator 15 and the phase conversion repeater 17 in the air and the communication between the investigation part 19 and the phase conversion repeater 17 in the water.

Description

  The present invention relates to an underwater investigation apparatus for investigating and checking underwater structures.

  In nuclear power plants and industrial plants, underwater investigation equipment is used for investigation and inspection of underwater structures and underwater foreign matter. The underwater investigation device includes an investigation unit that investigates and inspects the surroundings and the interior of the structure. In the case of a structure with a complicated internal structure, if the survey section is connected with a cable, the survey section will not operate because the cable and the structure will rub or the cable will wrap around the structure. Limited. For this reason, the underwater investigation apparatus provided with the investigation part to which the cable is not connected is desired. In addition, when investigating or inspecting structures while monitoring information (for example, video information) acquired from structures or foreign objects in the water outside the structure, it is necessary to transmit information from the water to the air. is there. Even when transmitting information in this way, it is desirable that the investigation unit does not use a cable as described above.

  Patent Document 1 discloses an underwater communication system using a laser light signal. Patent Document 2 discloses an underwater sensor network system that can acquire sensor data of an underwater sensor. Patent Document 3 discloses an underwater robot that performs wireless communication inside a unit and communicates between units by a non-conductive transmission medium.

JP 2009-55408 A JP 2007-323391 A JP2013-63702A

  When communication is performed using a laser beam signal as in the underwater communication system described in Patent Document 1, the laser beam may be cut off in a structure having a complicated structure, or the laser beam may not reach if the communication distance becomes long. Communication may not be possible.

  In the underwater sensor network system described in Patent Document 2, an underwater sensor equipped with an underwater wireless device is dropped from an aircraft, and data is transmitted / received by underwater communication using the underwater wireless device, and finally via a submarine cable. To communicate with land stations. For this reason, if the underwater structure has a complicated structure, it is difficult to dispose the underwater sensor inside the structure, and there is a concern that desired information cannot be acquired.

  In the underwater robot described in Patent Document 3, communication between the underwater robot and the outside is not considered. For this reason, it is difficult to transmit information acquired by the underwater robot from the water to the air, and to investigate and inspect the structure while monitoring this information.

  The present invention provides an underwater investigation device that can be used for underwater structures with a complicated structure and can communicate by relaying both portions even when there are an air portion and an underwater portion in the communication path. The purpose is to do.

  The underwater investigation apparatus according to the present invention has the following characteristics. A survey unit that includes an imaging unit and captures an image by the imaging unit in water; an underwater repeater that is installed in water and communicates with the survey unit wirelessly; and is installed in the air. A control unit for controlling, an air communication device installed in the air and connected to the control unit, an air antenna installed in the air, and an underwater antenna at least partially installed in water. The wireless communication device includes the underwater repeater and a phase conversion repeater that wirelessly communicates underwater. The underwater repeater relays underwater communication between the investigation unit and the phase conversion repeater. The communication rate differs between the communication between the air communication device and the phase conversion repeater in the air, and the communication between the investigation unit and the phase conversion relay in the air.

  The underwater investigation device according to the present invention can be used for an underwater structure having a complicated structure, and can communicate by relaying both portions even if there are an air portion and an underwater portion in the communication path. .

The figure which shows the reactor containment vessel by which the underwater investigation apparatus by Example 1 of this invention is arrange | positioned, and its inside. FIG. 2 is a block diagram illustrating a configuration of an underwater investigation device according to the first embodiment. The figure which shows the structure of the phase change repeater of the underwater investigation apparatus by Example 1. FIG. The figure which shows the structure of the investigation part of the underwater investigation apparatus by Example 1. FIG. The figure which shows the relationship between the carrier frequency of a sound wave signal, and received intensity. The flowchart of the process which the phase change repeater of the underwater investigation apparatus by Example 1 performs. The flowchart of the process which the investigation part of the underwater investigation apparatus by Example 1 performs. The figure which shows the tank of the industrial plant by which the underwater investigation apparatus by Example 2 of this invention is arrange | positioned.

  In the underwater investigation apparatus according to the present invention, the cable for control, communication, power supply, etc. is not connected to the investigation section for underwater investigation, and is suitable for investigation of underwater structures with complicated structures. Is available. Further, even when there are an aerial part and an underwater part in the communication path, communication is possible by relaying both parts. The underwater investigation apparatus according to the present invention can investigate an underwater structure even when, for example, the inside of a containment vessel of a nuclear power plant or a tank of an industrial plant is filled with water.

  Hereinafter, an underwater investigation apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, wireless communication refers to communication that does not use a transmission line, and is not limited to telecommunications. In the following embodiments, an example will be described in which the aerial part is wirelessly communicated mainly by radio waves, and the underwater part is mainly wirelessly transmitted by sound waves. However, the underwater investigation apparatus according to the present invention mainly uses sound waves. The underwater part can also perform wireless communication mainly by radio waves. In the case where the aerial part is mainly communicated by sound waves and the underwater part is mainly communicated by radio waves, the explanation of radio waves and the explanation of sound waves are appropriately switched in the following embodiments. However, when communicating with radio waves in water, the radio wave communication in water is performed over a short distance by taking into account the attenuation of radio waves in water and increasing the number of repeaters.

  The configuration and operation of the underwater investigation apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. In the present embodiment, an example will be described in which the underwater investigation device is used for investigation of a containment vessel of a nuclear power plant filled with water.

  FIG. 1 is a diagram showing a reactor containment vessel in which an underwater investigation apparatus according to the present embodiment is arranged and its inside. There is a reactor containment vessel 2 inside the reactor building 1, and a reactor pressure vessel 3 inside the reactor containment vessel 2. The reactor pressure vessel 3 is held by a pedestal 4. The reactor containment vessel 2 includes a through-hole 8 through which an electric wire, piping, and the like pass, and a pressure suppression chamber 6 installed inside the torus chamber 5 is connected. A grating 9 is provided in the reactor containment vessel 2 at substantially the same height as the reactor building floor 7. The grating 9 has an opening 10 in part. The pedestal 4 has an opening 12 in the vicinity of the bottom 11 of the reactor containment vessel 2 for an operator to enter and exit.

  Normally, water does not enter the reactor containment vessel 2, but in an emergency, water may be injected into the reactor containment vessel 2 and water may enter the reactor containment vessel 2. In this embodiment, such a situation is assumed. In this embodiment, it is assumed that the water surface 13 is under the grating 9.

  The underwater investigation device according to the present embodiment includes a control device 14, an in-air communication device 15, a phase conversion repeater 17, an underwater repeater 18, and an investigation unit 19.

  The control device 14 is disposed outside the reactor building 1, is connected to the air communication device 15, and controls the investigation unit 19. For example, the control device 14 instructs the investigation unit 19 to shoot a video to be investigated, or instructs the movement of the investigation unit 19 when the investigation unit 19 is a traveling type or a swimming type. In addition, the control device 14 acquires a video shot by the survey unit 19.

  The in-air communication device 15 is installed on the reactor building floor 7 in the reactor building 1 and is connected to the control device 14. The in-air communicator 15 is connected to one end of a communication cable. This communication cable extends through the penetration portion 8 into the reactor containment vessel 2, and the other end is connected to the air antenna 16 inside the reactor containment vessel 2.

  The air antenna 16 is located in the air inside the reactor containment vessel 2 and transmits and receives radio waves to and from the phase conversion repeater 17.

  The phase conversion repeater 17 is installed on the grating 9 inside the reactor containment vessel 2 and includes an air antenna 30 and an underwater antenna 31. The air antenna 30 is located in the air and transmits and receives radio waves to and from the air antenna 16. One end of the underwater antenna 31 is located below the water surface 13 (that is, a part of the underwater antenna 31 is located underwater), and transmits and receives sound waves to and from the underwater repeater 18.

  The underwater repeater 18 is lowered from the grating 9 and is disposed on the bottom 11 of the reactor containment vessel 2 in water at a position where sound waves can be transmitted to and received from the underwater antenna 31 of the phase conversion repeater 17. The underwater relay 18 transmits and receives sound waves to and from the phase conversion relay 17 and the investigation unit 19, and relays communication between the phase conversion relay 17 and the investigation unit 19 using sound waves.

  The investigation unit 19 is lowered from the grating 9 and is disposed on the bottom 11 of the reactor containment vessel 2 in water at a position where sound waves can be transmitted to and received from the underwater relay 18. The investigation unit 19 shoots an image to investigate and check underwater structures and investigate underwater foreign objects. The video captured by the investigation unit 19 is transmitted to the control device 14 via the underwater relay 18, the phase conversion relay 17, and the air communication device 15.

  FIG. 2 is a block diagram showing the configuration of the underwater investigation apparatus according to this embodiment. The connection relationship between each component of the underwater research apparatus will be described with reference to FIG. The control device 14 and the air communication device 15 are connected by a cable. As described above with reference to FIG. 1, the aerial communication device 15 is connected to the aerial antenna 16 via a communication cable, and performs wireless communication with the phase conversion repeater 17.

  The phase conversion repeater 17 transmits information to and from the underwater repeater 18 by communication using sound waves. The phase conversion repeater 17 includes an air communication unit 20, a rate conversion unit 21, and an underwater communication unit 22, which are connected to each other. The air communication unit 20 performs radio communication with the air communication device 15 using radio waves. The underwater communication unit 22 performs sound wave communication with the underwater repeater 18. The communication rate (communication speed) is different between radio communication using radio waves performed by the in-air communication unit 20 and radio communication using sound waves performed by the underwater communication unit 22. For this reason, the rate conversion unit 21 converts the communication rate so that one communication rate matches the other communication rate, and connects and relays two communications with different communication rates. Further, the rate conversion unit 21 controls the carrier frequency of the sound wave signal in the wireless communication performed by the underwater communication unit 22 and the compression coefficient (or compression ratio) in the video compression performed by the survey unit 19.

  The underwater repeater 18 communicates with the phase conversion repeater 17 (underwater communication unit 22) and the investigation unit 19 using sound waves, and relays communication between the phase conversion repeater 17 and the investigation unit 19. To do. Note that the signal carrier frequency is the same in the communication between the phase conversion repeater 17 and the underwater repeater 18 and in the communication between the underwater repeater 18 and the investigation unit 19.

  FIG. 3 is a diagram showing a configuration of the phase conversion repeater 17 of the underwater investigation apparatus according to the present embodiment. As described with reference to FIG. 2, the phase conversion repeater 17 includes the air communication unit 20, the rate conversion unit 21, and the underwater communication unit 22, and wireless communication using radio waves with the air communication device 15. The information is transmitted by the wireless communication using the sound wave via the underwater relay 18 with the investigation unit 19. An air antenna 30 is connected to the air communication unit 20, and an underwater antenna 31 is connected to the underwater communication unit 22. Further, the phase conversion repeater 17 includes a battery 23 and is driven by power supplied from the battery 23.

  FIG. 4 is a diagram showing a configuration of the investigation unit 19 of the underwater investigation apparatus according to the present embodiment. In the present embodiment, the investigation unit 19 is of a traveling type, travels on the bottom 11 of the reactor containment vessel 2 and moves to investigate the inside of the reactor containment vessel 2. However, in the underwater investigation apparatus according to the present invention, as the investigation unit 19 capable of investigating underwater, a swimming type that swims and moves underwater, or a fixed type that is fixed to the reactor containment vessel 2 by a fixing member may be used. it can.

  The investigation unit 19 includes a housing 40, and the housing 40 is provided with two crawlers 41, an imaging unit 42, an underwater communication device 43, and an antenna 44, which are connected to each other by a cable. The investigation unit 19 can travel on the crawler 41 (for example, an endless track). The imaging unit 42 is a device that captures an investigation target video (at least one of a moving image and a still image), and for example, a camera can be used. In addition, the imaging unit 42 compresses the captured video. The underwater communication device 43 performs sound wave communication with the underwater relay 18 via the antenna 44. The antenna 44 transmits and receives sound waves to and from the underwater repeater 18. Further, the investigation unit 19 includes a battery 45 and is driven by power supplied from the battery 45.

  The investigation unit 19 communicates by sound waves with the underwater repeater 18 and transmits the image captured by the imaging unit 42 to the underwater repeater 18. Information is transmitted to and received from 17.

  FIG. 5 is a diagram illustrating the relationship between the carrier frequency of the sound wave signal and the received intensity. As shown in FIG. 5, when the carrier frequency of the sound wave increases, attenuation increases and the reception intensity decreases. Therefore, in underwater communication, it is necessary to select a carrier frequency according to the reception intensity of sound waves. In the underwater investigation apparatus according to the present embodiment, the rate conversion unit 21 of the phase conversion repeater 17 monitors the reception intensity of the sound wave signal and controls the carrier frequency so that the reception intensity becomes a certain value or more.

  The sound wave is attenuated as the communication distance increases, and the reception intensity decreases. However, in order to reliably receive a sound wave signal, the sound wave reception intensity needs to be a certain value (threshold value) or more. Therefore, when the survey unit 19 moves and the distance between the survey unit 19 and the underwater relay 18 increases and the reception intensity of the sound wave signal received by the phase conversion relay 17 decreases, the rate conversion unit 21 The carrier frequency of the sound wave signal is reduced so that the reception intensity of the sound wave signal is increased.

In addition, with the attenuation of sound waves due to an increase in communication distance, it is necessary to reduce the amount of information transmitted by sound waves. For this reason, it is necessary to reduce the compression coefficient in video compression. The compression coefficient is an index indicating how much data is compressed and is the reciprocal of the compression ratio. The compression ratio is a ratio between the data amount before compression and the data amount after compression. That is,
Compression coefficient = 1 / compression ratio = (data amount after compression) / (data amount before compression)
It is expressed. Even if the communication distance increases and the sound wave attenuates by reducing the amount of information transmitted by the sound wave by reducing the compression coefficient, the communication between the phase conversion repeater 17 and the investigation unit 19 is not interrupted. Is possible. For this reason, in the underwater investigation device according to the present embodiment, even when the investigation unit 19 moves and the distance between the investigation unit 19 and the underwater relay 18 increases, the control device 14 does not interrupt the investigation result of the investigation unit 19. Can be received.

  FIG. 6 is a flowchart of processing performed by the phase conversion repeater 17. The process which the phase conversion repeater 17 performs is demonstrated using FIG. As described above, the phase conversion repeater 17 communicates by sound waves with the investigation unit 19 via the underwater repeater 18, and at the same time as the carrier frequency of the sound wave signal and the video compression performed by the investigation unit 19. Control the compression factor.

  In step S100, the underwater investigation device starts an investigation.

  In step S101, the rate conversion unit 21 performs initial setting of transmission parameters. The transmission parameter refers to the compression of information (video data) by the carrier frequency fSG of the sound wave signal and the video compression performed by the survey unit 19 in the communication using the sound wave performed by the underwater communication unit 22 with the survey unit 19. The coefficient PS. The phase conversion repeater 17 sets the carrier frequency fSG to f0, and sets the compression coefficient PS to 1. The initial value f0 of the carrier frequency fSG is based on the positional relationship between the underwater repeater 18 disposed on the bottom 11 of the reactor containment vessel 2 and the underwater antenna 31 of the phase conversion repeater 17, and the underwater repeater 18 and the investigation unit 19. It can be determined according to the positional relationship.

  In step S <b> 102, the underwater communication unit 22 receives a video signal from the survey unit 19. The investigation unit 19 transmits to the phase conversion repeater 17 a signal of the investigation target video imaged by the imaging unit 42 or transmits a dummy video signal as will be described later.

  In step S <b> 103, the rate conversion unit 21 analyzes and obtains the reception intensity P (for example, the reception intensity of the video signal) of the sound wave signal received from the investigation unit 19.

  If the value of the reception strength P is larger than the preset threshold value Sh in step S104, the process returns to step S102 and the video signal is continuously received. If the value of the reception strength P is equal to or less than the threshold value Sh, the process proceeds to step S105. The threshold value Sh can be determined according to the characteristics of the rate conversion unit 21 of the phase conversion repeater 17 and the resolution required for the captured video.

  In step S105, the rate conversion unit 21 changes the transmission parameter. The rate conversion unit 21 decreases the carrier frequency fSG by ΔfSG and decreases the compression coefficient PS by ΔPS. That is, (fSG−ΔfSG) is a new carrier frequency fSG, and (PS−ΔPS) is a new compression coefficient PS. Note that ΔfSG and ΔPS are preset values, and can be determined based on, for example, these initial setting values (f0 and 1).

  In step S106, the underwater communication unit 22 transmits the changed transmission parameter to the investigation unit 19 by underwater wireless communication using a sound wave (carrier frequency is fSG). After the transmission parameter is transmitted, the process of the phase conversion repeater 17 returns to the reception of the video signal in step S102.

  FIG. 7 is a flowchart of the process performed by the investigation unit 19. Processing performed by the survey unit 19 will be described with reference to FIG. As described above, in the investigation unit 19, the imaging unit 42 shoots an image to conduct an investigation / inspection of an underwater structure and an investigation of a foreign substance in the water, and the phase conversion repeater 17 through the underwater repeater 18. Communication with the sound wave. In addition, the investigation unit 19 compresses the video information captured by the imaging unit 42 and transmits the compressed information to the phase conversion repeater 17.

  In step S200, the investigation unit 19 starts an investigation.

  In step S201, the underwater communication device 43 performs initial setting of transmission parameters (the carrier frequency fSG of the sound wave signal and the compression coefficient PS of the video information as described in step S101 of FIG. 6). The underwater communication device 43 sets the carrier frequency fSG to f0, and sets the compression coefficient PS to 1. The initial value f0 of the carrier frequency fSG is the same value as the initial value f0 of the carrier frequency fSG set by the rate conversion unit 21 of the phase conversion repeater 17 (see step S101 in FIG. 6).

  In step S202, the underwater communication device 43 transmits a dummy video signal to the phase conversion repeater 17. Any signal can be used as the dummy video signal.

  In step S <b> 203, the underwater communication device 43 determines whether a transmission parameter signal is received from the phase conversion repeater 17. The phase conversion repeater 17 transmits the changed transmission parameter to the investigation unit 19 by underwater wireless communication using sound waves (see step S106 in FIG. 6). If a transmission parameter signal is received from the phase conversion repeater 17, the process proceeds to step S204. If a transmission parameter signal is not received, the process proceeds to step S205.

  In step S204, the underwater communication device 43 changes the transmission parameter to the transmission parameter received from the phase conversion repeater 17. That is, the carrier frequency fSG is decreased by ΔfSG, (fSG−ΔfSG) is set as a new carrier frequency fSG, and the compression coefficient PS is decreased by ΔPS, and (PS−ΔPS) is set as a new compression coefficient PS.

  In step S <b> 205, the investigation unit 19 acquires an image of an investigation target (for example, an underwater structure or a foreign object). The imaging unit 42 captures a video to be investigated.

  In step S206, the imaging unit 42 compresses the captured video using the compression coefficient PS. For example, when the compression coefficient PS is 0.25, an operation of thinning out one pixel in each of the upper and lower directions and the left and right directions of the video is performed. An arbitrary method can be used as a method for compressing the video. In addition to a method of thinning out pixels, a method of averaging adjacent pixel values, a compression technique using difference information, or the like can be used. If the compression coefficient PS is 1, the video is not compressed.

  In step S207, the underwater communication device 43 transmits the compressed video signal to the phase conversion repeater 17 by underwater wireless communication using a sound wave (carrier frequency is fSG). After the transmission of the video signal, the process of the investigation unit 19 returns to the determination of whether or not the transmission parameter is received in step S203.

  As described above, the underwater investigation apparatus according to the present embodiment includes the phase conversion repeater 17, and the control signal and the investigation video are transmitted between the control apparatus 14 installed in the air and the investigation unit 19 installed in the water. Transmission can be performed mainly wirelessly. The phase conversion repeater 17 controls the carrier frequency fSG of the sound wave signal in the communication using the sound wave and the compression coefficient PS of the information in the video compression, and the two communications (communication by the sound wave in water and the communication rate) having different communication rates. Communication using radio waves in the air). Therefore, the underwater investigation apparatus according to the present embodiment can connect the wireless communication in the air and underwater, and the investigation unit 19 moves and the phase conversion repeater 17 is moved by the control of the carrier frequency fSG and the compression coefficient PS. Even if the reception intensity of the received sound wave decreases, the communication between the phase conversion repeater 17 and the investigation unit 19 is not interrupted. For this reason, when the underwater investigation device according to the present embodiment is used, the investigation result of the investigation unit 19 can be obtained without interruption, so that information (for example, video information) obtained from the underwater structure or foreign matter can be obtained. The structure can be investigated and inspected while continuously monitoring outside.

  The underwater investigation apparatus according to Example 2 of the present invention will be described with reference to FIG. In the present embodiment, an example will be described in which the underwater investigation device is used for investigation of a tank of an industrial plant whose inside is filled with water.

  FIG. 8 is a diagram showing a tank of an industrial plant in which the underwater investigation device according to the present embodiment is arranged. In FIG. 8, the same reference numerals as those in the first embodiment denote the same or common elements as those in the first embodiment, and the description of these elements is omitted. The underwater investigation apparatus according to the present embodiment has the same configuration as the underwater investigation apparatus according to the first embodiment, except that the phase conversion repeater 17 is divided into two parts, an air part 53 and an underwater part 54, and a plurality of parts. The difference is that the underwater relays 18a and 18b are provided. In this embodiment, the number of underwater repeaters is two, but may be three or more. The plurality of underwater repeaters are connected to each other in series.

  The control device 14 and the air communication device 15 are installed outside the tank 60 in which water is stored, and are connected to each other by a cable. The phase conversion repeater 17 includes an aerial part 53 and an underwater part 54. The aerial part 53 is installed outside the tank 60 or in the air above the water surface 50, and the underwater part 54 is in the water below the water surface 50. Installed. The aerial part 53 and the underwater part 54 are connected to each other by a cable 55.

  The aerial section 53 of the phase conversion repeater 17 includes the aerial communication section 20 and the rate conversion section 21 of the phase conversion repeater 17 described in the first embodiment, and the underwater section 54 includes the phase conversion described in the first embodiment. The underwater communication unit 22 of the repeater 17 is provided. The rate conversion unit 21 may be provided in the underwater unit 54. The air unit 53 includes an air antenna 30 located in the air, and performs wireless communication with the air communication device 15 using radio waves in the air. The underwater unit 54 includes an underwater antenna 31 located underwater, and performs wireless communication using sound waves in water with the underwater repeater 18a. The processes performed by the air communication unit 20 and the rate conversion unit 21 of the air unit 53 and the underwater communication unit 22 of the underwater unit 54 are the same as those in the first embodiment.

  The underwater relays 18a and 18b have the same configuration as the underwater relay 18 described in the first embodiment, and are installed on the wall surface (or the bottom surface) of the tank 60 in water. The underwater relay 18a transmits / receives sound waves to / from the underwater portion 54 of the phase conversion repeater 17 and to the underwater relay 18b, and transmits sound waves to / from the underwater portion 54 and between the underwater relay 18b. It is placed in a position where it can transmit and receive The underwater relay 18b is disposed at a position where it can transmit and receive sound waves to and from the underwater relay 18a and the investigation unit 19, and can transmit and receive sound waves to and from the underwater relay 18a and the investigation unit 19. The That is, the underwater repeaters 18a and 18b relay the communication of the control signal and the investigation video by the sound wave between the phase conversion repeater 17 and the investigation unit 19.

  In the underwater investigation apparatus according to the present embodiment, the underwater portion 54 of the phase conversion repeater 17 is located in the water, and a plurality of underwater repeaters 18a and 18b are used. Is easier to do.

  In addition, this invention is not limited to said Example, Various modifications are included. For example, the above-described embodiments are described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to an aspect including all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, with respect to a part of the configuration of each embodiment, the configuration of another embodiment can be added, deleted, or replaced.

  DESCRIPTION OF SYMBOLS 1 ... Reactor building, 2 ... Reactor containment vessel, 3 ... Reactor pressure vessel, 4 ... Pedestal, 5 ... Torus chamber, 6 ... Pressure suppression chamber, 7 ... Reactor building floor, 8 ... Penetration part, 9 ... Grating DESCRIPTION OF SYMBOLS 10 ... Grating opening, 11 ... Bottom of reactor containment vessel, 12 ... Pedestal opening, 13 ... Water surface, 14 ... Control device, 15 ... Air communication device, 16 ... Air antenna, 17 ... Phase conversion Repeater, 18, 18a, 18b ... underwater repeater, 19 ... inspection unit, 20 ... in-air communication unit, 21 ... rate conversion unit, 22 ... underwater communication unit, 23 ... battery, 30 ... in the air of phase conversion repeater Antenna: 31 ... Underwater antenna of phase conversion repeater, 40 ... Housing, 41 ... Crawler, 42 ... Imaging unit, 43 ... Underwater communication device, 44 ... Antenna, 45 ... Battery, 50 ... Water surface, 53 ... Phase conversion repeater 54 ... The underwater part of the phase change repeater 55 ... cable, 60 ... tank.

Claims (6)

An investigation unit that includes an imaging unit and shoots an image by the imaging unit in water;
An underwater repeater that is installed in the water and communicates wirelessly with the research unit underwater;
A control unit installed in the air and controlling the investigation unit;
An air communicator installed in the air and connected to the control unit;
An underwater antenna installed in the air and an underwater antenna at least a part of which is installed in water, communicates with the air communication device in the air wirelessly, and wirelessly communicates with the underwater repeater in the water A phase change repeater that communicates with
The underwater repeater relays underwater communication between the investigation unit and the phase conversion repeater,
The communication between the air communication device and the phase conversion repeater in the air, and the communication between the investigation unit and the phase conversion relay in the water have different communication rates.
Underwater investigation device characterized by that. The phase conversion repeater includes an air communication unit that communicates wirelessly with the air communication device, an underwater communication unit that communicates wirelessly with the underwater relay, and a rate conversion unit.
The rate conversion unit converts the communication rate to communicate between the air communicator in the air and the air communicator, and to communicate between the underwater repeater and the underwater communicator in water. The underwater investigation device according to claim 1, wherein   When the value of the received intensity of the signal received from the underwater repeater by the underwater communication unit is equal to or lower than a preset threshold, the rate conversion unit determines the carrier frequency of the signal of the communication in water. The underwater investigation device according to claim 2, wherein the underwater investigation device is decreased by a preset value. The investigating unit compresses the video imaged by the imaging unit, transmits the video to the underwater communication unit of the phase conversion repeater via the underwater repeater,
The rate conversion unit is configured so that when the reception intensity value of the signal received from the underwater repeater by the underwater communication unit is equal to or less than a preset threshold value, the investigating unit compresses the video. The underwater investigation apparatus according to claim 3, wherein the compression coefficient is decreased by a preset value. Communication between the investigation unit and the underwater relay in water, and communication between the underwater relay and the phase conversion relay in water are performed using sound waves.
The underwater investigation device according to claim 1, wherein communication between the air communication device and the phase conversion repeater in the air is performed using radio waves.   The underwater investigation apparatus according to any one of claims 1 to 5, comprising a plurality of the underwater repeaters.

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