Undersea observation device, undersea observation system, and transmission method

Abstract

An undersea observation device 1 is provided with: an observation unit 11 that observes an undersea environment; a conversion unit 13 that converts observation data observed by the observation unit 11 into a vibration pattern according to a predetermined algorithm; and a transmission unit 15 that transmits the observation data via an optical fiber cable 3 laid on the seabed, by vibrating the optical fiber cable 3 according to the vibration pattern.

Description

Underwater observation device, underwater observation system, and transmission method

[0001] The present disclosure relates to an underwater observation device, an underwater observation system, and a transmission method.

[0002] With the growing demand for underwater sensors and equipment, expectations are rising for underwater wireless communication. Underwater wireless communication can be broadly divided into three types: acoustic communication using sound waves, low-frequency electromagnetic field communication using radio waves, and optical wireless communication using light.

[0003] Furthermore, optical fiber sensing systems that use optical fiber cables as strain sensors have been studied (Non-Patent Document 1), and many optical fiber cables are laid on the seabed (Non-Patent Document 2).

[0004] Optical Fiber Sensing Association, "Optical Fiber System: Basic Principles and Types," [online], Internet <URL: https: / / www.phosc.jp / article / 000025.html> TeleGeography, "Submarine Cable Map," [online], Internet <URL: https: / / www.submarinecablemap.com / >

[0005] Conventional ocean observations use Argo floats and other instruments to observe water temperature, salinity, and other parameters. Argo floats drift at a depth of 1,000 meters for approximately 10 days, then sink to a specified depth and observe water temperature and salinity before rising to the surface. After surfacing, the Argo float transmits the observation data to a satellite via wireless communication, then sinks back to the drifting depth and repeats the observation and transmission process. Ocean observations using Argo floats have the drawback of transmitting observation data once every 10 days, making real-time transmission impossible.

[0006] The use of underwater wireless communication to transmit observation data poses the following challenges. Specifically, underwater acoustic communication, which uses sound waves, has limitations on frequency and frequency bandwidth depending on the communication distance due to the physical properties of seawater, and also has challenges specific to multipath environments and time fluctuations. Low-frequency electromagnetic field communication, which uses radio waves, has slow communication speeds, and sending and receiving image and video data takes time. Optical wireless communication, which uses light, has challenges such as communication limitations due to its vulnerability to turbidity.

[0007] In the optical fiber sensing system of Non-Patent Document 1, research has been conducted into detecting the position and intensity of events that cause distortion, such as road vibrations, but no consideration has been given to using it for marine observation.

[0008] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a technology for transmitting observation data obtained underwater.

[0009] In order to achieve the above-mentioned objective, one aspect of the present disclosure is an underwater observation device comprising an observation unit that observes the underwater environment, a conversion unit that converts the observation data observed by the observation unit into a vibration pattern according to a predetermined algorithm, and a transmission unit that applies vibrations to an optical fiber cable laid on the seabed according to the vibration pattern and transmits the observation data via the optical fiber cable.

[0010] One aspect of the present disclosure is an underwater observation system comprising an underwater observation device and a detection device, wherein the underwater observation device comprises an observation unit that observes the underwater environment, a conversion unit that converts observation data observed by the observation unit into a vibration pattern, and a transmission unit that applies vibrations to an optical fiber cable laid on the seabed in accordance with the vibration pattern and transmits the observation data via the optical fiber cable, and the detection device comprises a detection unit that detects the vibration pattern of the optical fiber cable and an analysis unit that analyzes the vibration pattern and acquires the observation data.

[0011] One aspect of the present disclosure is a transmission method performed by an underwater observation device, which observes the underwater environment, converts the observed observation data into a vibration pattern, applies vibrations to an optical fiber cable laid on the seabed in accordance with the vibration pattern, and transmits the observation data via the optical fiber cable.

[0012] According to the present disclosure, it is possible to provide a technology for transmitting observation data obtained underwater.

[0013] Fig. 1 shows the overall configuration of an underwater observation system according to this embodiment. Fig. 2 is a block diagram showing the configuration of an underwater observation device and a detection device. Fig. 3 is an explanatory diagram for explaining an example of processing by a conversion unit. Fig. 4 is a flowchart showing a method for transmitting observation data. Fig. 5 shows an example of a hardware configuration.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0015] 1 is a block diagram showing an overview of an underwater observation system according to this embodiment. The underwater observation system shown in the figure includes an underwater observation device 1, a detection device 2, and an optical fiber cable 3 connecting the underwater observation device 1 and the detection device 2.

[0016] The optical fiber cable 3 is an optical fiber cable laid on the seabed. In this embodiment, the existing optical fiber cable 3 laid on the seabed is used as a transmission line to transmit observation data obtained underwater.

[0017] The underwater observation device 1 (ocean observation device) observes various environmental information underwater (ocean), converts the observed observation data into a vibration pattern (vibration signal), and transmits (transmits) it to the detection device 2 via the optical fiber cable 3.

[0018] The underwater environmental information includes physical conditions, chemical components, environmental DNA, etc. Physical conditions include temperature, water flow velocity, salinity, pH, etc. Chemical components include nutrients such as phosphorus, nitrogen, and potassium, and iron.

[0019] The underwater observation device 1 may be a battery-powered device that includes a battery (power source) and is powered by the battery. In this case, the underwater observation device 1 periodically (e.g., every few months) surfaces to replace the power supply. The underwater observation device 1 may also be a power-supply type device that is powered by power supplied from the repeater 4. In this case, the underwater observation device 1 and the repeater 4 are connected by a power line (not shown).

[0020] The detector 2 detects a vibration pattern propagated in the longitudinal direction of the optical fiber cable 3, and analyzes the detected vibration pattern to obtain observation data.

[0021] FIG. 2 is a block diagram showing the configuration of the underwater observation device 1 and the detection device 2.

[0022] The underwater observation device 1 of this embodiment is placed adjacent to or near the optical fiber cable 3 laid underwater to transmit observation data by applying vibrations to the optical fiber cable 3. This allows the underwater observation device 1 to observe the seabed environment, which is rich in nutrients. The underwater observation device 1 shown in the figure includes a control unit 10 and a transmission unit 15. The control unit 10 includes an observation unit 11, a memory unit 12, and a conversion unit 13.

[0023] The observation unit 11 observes various underwater environments and stores the observations in the memory unit 12. Specifically, the observation unit 11 observes underwater physical conditions (water temperature, water flow velocity, salinity, pH, etc.), chemical components (nutrients, iron, etc.), environmental DNA, etc. The observation unit 11 can use various measuring instruments used in oceanographic observations, such as temperature sensors and CTD (Conductivity Temperature Depth Profiler) sensors. The CTD sensor observes electrical conductivity, water temperature, depth (pressure), etc.

[0024] The storage unit 12 (database) stores (accumulates) the observation data observed by the observation unit 11 .

[0025] The converter 13 converts the observation data observed by the observer 11 into a vibration pattern (vibration signal) according to a predetermined algorithm. That is, the converter 13 converts the observation data into a vibration pattern that is data that can be transmitted by the transmitter 15. The converter 13 may convert the observation data stored in the memory 12 into a vibration pattern.

[0026] FIG. 3 is an explanatory diagram illustrating an example of the processing of the conversion unit 13. In the illustrated example, the observation data of "water temperature 10 degrees" is converted into a vibration pattern. The conversion unit 13 reads out "water temperature 10 degrees" (observation data) stored in the memory unit 12 and converts it into a transmission format. Here, the transmission format has a header, data, and an end. The type of observation data, such as water temperature, water flow speed, pH, and nutrients, is set in the header. The value of the data observed by the observation unit 11 is set in the data. Data indicating the end is set in the end. Here, the conversion unit 13 sets "data indicating water temperature" in the header, sets "10 degrees" in the data, and sets "data indicating the end" in the end.

[0027] The converter 13 then converts the observation data converted into the transmission format into a vibration pattern according to a predetermined algorithm. The converter 13 may convert the entire observation data into a vibration pattern using a predetermined algorithm, or the converter 13 may convert the header, data, and end into vibration patterns using different algorithms. In the latter case, the converter 13 may convert the data into a vibration pattern using a conversion algorithm corresponding to the type of header.

[0028] A vibration pattern is a combination of multiple vibrations with different vibration intensities, as shown in Figure 2. Each vibration can be defined by its vibration intensity and length (duration).

[0029] The transmitter 15 applies vibrations to the optical fiber cable 3 laid on the seabed in accordance with the vibration pattern converted by the converter 13, and transmits the observation data to the detection device 2 via the optical fiber cable 3. Specifically, the transmitter 15 physically transmits the vibration pattern data converted by the converter 13 as vibrations to the optical fiber cable 3. The transmitter 15 transmits multiple vibrations set in the vibration pattern to the optical fiber cable 3. In the vibration pattern, each vibration is defined using a vibration intensity and a vibration length (time).

[0030] For example, a vibration motor can be used for the transmitter 15. The vibration motor has a vibrator attached to its shaft and generates vibrations by rotation. When the vibration motor is driven, vibrations according to a vibration pattern are transmitted to the optical fiber cable 3.

[0031] The detection device 2 is connected to the underwater observation device 1 via an optical fiber cable 3 and is placed on land, for example, at an observation station. The illustrated detection device 2 includes a detection unit 21 and an analysis unit 22. The detection unit 21 detects the vibration pattern of the optical fiber cable 3. Existing optical fiber vibration detection technology can be used to detect the vibration of the optical fiber cable 3. For example, a high-precision optical fiber vibration distribution measurement technology using an optical measurement method called OFDR (Optical Frequency Domain Reflectometry) can be applied. This is described in the following document.

[0032] "World's first demonstration of communications equipment monitoring technology using the vibration state sensed by communications optical fiber as a sensor - Aims to grasp city environmental information comprehensively and utilize it for disaster prevention measures" (https: / / group.ntt / jp / newsrelease / 2021 / 09 / 27 / 210927a.html) The receiving unit 22 analyzes the vibration pattern detected by the detecting unit 21 to obtain observation data. The receiving unit 22 decodes the observation data from the vibration pattern by using an analysis algorithm that corresponds to the conversion algorithm used by the converting unit 13 of the underwater observation device 1.

[0033] FIG. 4 is a flowchart showing the operation of the underwater observation device 1 of this embodiment.

[0034] The observation unit 11 observes the environment such as the physical state, chemical components, and environmental DNA in the ocean (S11). The observation unit 11 stores the observed observation data in the storage unit 12 (S12).

[0035] The converter 13 converts the observation data stored in the memory 12 into a vibration pattern (vibration signal) according to a predetermined algorithm (S13). The transmitter 15 applies vibration to the optical fiber cable 3 laid on the seabed according to the vibration pattern, and transmits the observation data to the detector 2 via the optical fiber cable 3 (S14).

[0036] The underwater observation device 1 of this embodiment described above comprises an observation unit 11 that observes the underwater environment, a conversion unit 13 that converts the observation data observed by the observation unit 11 into a vibration pattern according to a predetermined algorithm, and a transmission unit 15 that applies vibrations to an optical fiber cable 3 laid on the seabed according to the vibration pattern and transmits the observation data via the optical fiber cable 3.

[0037] As a result, in this embodiment, observation data obtained by underwater observation can be transmitted underwater using an optical fiber cable laid on the seabed. In this embodiment, by utilizing an existing optical fiber cable, there is no need to install a new transmission line, and an underwater observation system can be constructed at low cost. In addition, since many optical fiber cables are laid on the seabed, a wide range of underwater environments can be observed and observation data can be transmitted via the optical fiber cable 3.

[0038] In addition, in this embodiment, by using the optical fiber cable 3 laid on the seabed as a transmission path, the observation data (physical state, chemical components, environmental DNA, etc.) observed by the observation unit 11 can be transmitted in real time, making it possible to easily obtain clues to the impact of the ocean on humanity.

[0039] Furthermore, in this embodiment, by installing the underwater observation device 1 near the optical fiber cable 3 laid on the seabed, it is possible to easily perform environmental observations in deep-sea areas, which have been difficult to observe until now and where regular observations have not been conducted.

[0040] The control unit 10 of the underwater observation device 1 described above can use, for example, a general-purpose computer system as shown in Fig. 5. The computer system shown in the figure includes a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device 906. The memory 902 and the storage 903 are storage devices. In this computer system, the CPU 901 executes a predetermined program loaded on the memory 902, thereby realizing each function of the control unit 10.

[0041] The control unit 10 may be implemented in one computer or in multiple computers. The program of the control unit 10 may be stored in a computer-readable recording medium such as a HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc), or may be distributed via a network. The computer-readable recording medium may be, for example, a non-transitory recording medium.

[0042] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0043] 1: Underwater observation device 11: Observation unit 12: Memory unit 13: Conversion unit 15: Transmission unit 2: Detection device 21: Detection unit 22: Analysis unit 3: Optical fiber cable 4: Repeater

Claims

1. An underwater observation device comprising: an observation unit which observes the underwater environment; a conversion unit which converts the observation data observed by said observation unit into a vibration pattern in accordance with a predetermined algorithm; and a transmission unit which applies vibrations to an optical fiber cable laid on the seabed in accordance with said vibration pattern, and transmits the observation data via said optical fiber cable.

2. The underwater observation device according to claim 1, wherein the vibration pattern is a combination of a plurality of vibrations having different vibration intensities.

3. An underwater observation device as described in claim 1, further comprising a memory unit for storing the observation data, and wherein the conversion unit converts the observation data stored in the memory unit into a vibration pattern.

4. An underwater observation system comprising an underwater observation device and a detection device, wherein the underwater observation device comprises an observation unit that observes the underwater environment, a conversion unit that converts observation data observed by the observation unit into a vibration pattern, and a transmission unit that applies vibrations to an optical fiber cable laid on the seabed in accordance with the vibration pattern and transmits the observation data via the optical fiber cable, and the detection device comprises a detection unit that detects the vibration pattern of the optical fiber cable, and an analysis unit that analyzes the vibration pattern to obtain the observation data.

5. A transmission method performed by an underwater observation device, comprising: observing the underwater environment; converting the observed observation data into a vibration pattern; applying vibrations to an optical fiber cable laid on the seabed in accordance with the vibration pattern; and transmitting the observation data via the optical fiber cable.

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