US20200331573A1

US20200331573A1 - Underwater drop type position guiding apparatus

Info

Publication number: US20200331573A1
Application number: US16/386,861
Authority: US
Inventors: Hyeung Sik Choi
Original assignee: R&DB Foundation of Korea Maritime and Ocean University
Current assignee: R&DB Foundation of Korea Maritime and Ocean University
Priority date: 2019-04-17
Filing date: 2019-04-17
Publication date: 2020-10-22

Abstract

Disclosed is an underwater drop type position guiding apparatus, the apparatus including an underwater drop type body having a lower end part in a shape of a cone pointing downward. The underwater drop type body is provided with a GPS module, an underwater communication transmitter, a controller, and a battery. After being installed on the sea floor by being dropped to the water from above the surface of the water, the apparatus guides underwater coordinates to various underwater vehicles using GPS location information having received from above the surface of the water.

Description

BACKGROUND

Field of the Invention

The present invention relates to an underwater drop type position guiding apparatus and, more particularly, to an underwater drop type position guiding apparatus, wherein the apparatus is dropped into water and is fixed to a sea floor and guides an underwater vehicle exploring the periphery of a position.

Description of the Related Art

Unlike a waterborne probe operated on the surface of water, in case of an underwater vehicle for underwater exploration including an autonomous underwater vehicle (AUV), which is operated to perform underwater tasks such as collecting information in the water, it is difficult to locate a position of the underwater vehicle using radar, optical equipment, a GPS, and the like.
When an ocean is turbid, it is not possible to locate the position of the underwater vehicle using radar or optical equipment, and locating a position based on GPS signals is also not possible because the GPS signals in the water may not be received.
Therefore, in the water, a position is located by using an inertial measurement unit (IMU) or a Doppler Velocity Log (DVL).
The IMU measures inertia of three-axis directions using a precision gyro sensor and integrates the inertia to calculate the current position and velocity, and a technology has been developed to such an extent that only an error of about 10 km occurs even when an underwater object has moved thousands of kilometers.
The DVL uses the Doppler effect to determine the velocity of an object in motion under water, and calculates the current position on the basis of identified velocity. The underwater environment is very diverse and complicated, and the water depth, state of tidal current, and a noise of the underwater vehicle itself affect the DVL, so the accuracy of the position obtained using the DVL is greatly degraded depending on the underwater environment.
Because the position information in the water using navigation devices such as the IMU and the DVL is accumulated with errors as navigation is continued, the reliability decreases with time.
Therefore, the underwater vehicle should correct its own position by periodically ascending to above the surface of the water to receive GPS information, or by receiving position information from other position guiding apparatus in the water.
In order to receive position information from the position guiding apparatus, the position guiding apparatus for transmitting position information to the exploration area of the underwater vehicle should be installed in advance.
Conventionally, a buoy-type position guiding apparatus was used, which floated on the surface of the water and transmitted position information to the underwater vehicle.
However, there is a problem for the buoy-type position guiding apparatus such as above in that the apparatus floats along tidal current, thereby changing a position thereof. In addition, because the position information device provided on the surface of the water may not transmit the position information to the underwater vehicle exploring the deep sea, there is a problem that the underwater vehicle has to ascend again to near the surface of the water to use the position information device of this type.
Such a problem can be solved by using the position guiding apparatus that is dropped into water and installed on the sea floor. However, in order to install the position guiding apparatus on the sea floor, a process is necessary to descend the position guiding apparatus to the sea floor by being suspended by a cable from a ship 20 and then to fix the position guiding apparatus to the sea floor. Accordingly, it takes much time and cost to pass through a process of installing the position guiding apparatus.
In addition, during the position guiding apparatus reaching the sea floor after being dropped into the water, the position of the position guiding apparatus may deviate from the planned installation position due to the influence of the tidal current, so that the position information may not be accurately guided to the underwater vehicle.
Further, because the position information device installed on the seafloor has to continuously transmit the position information to the outside, there is a problem that the battery built in the position information device is consumed quickly and may not be operated for a long time.

SUMMARY

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the conventional art, and an object of the present invention is to provide an underwater drop type position guiding apparatus that is, after receiving GPS position information from above the surface of the water, dropped into the water, descended, and then automatically fixed to the sea floor.
In order to solve the above-mentioned problems, the present invention provides the underwater drop type position guiding apparatus for being dropped into water from above a surface of the water and for being installed on a sea floor, the apparatus, the apparatus including: an underwater drop type body including a tubular shell extending vertically, a cover coupled with an upper end part of the tubular shell, a cone-shaped head pointing downward coupled with the lower end part of the tubular shell to be embedded and fixed on the sea floor by own weight thereof and being manufactured with material having a specific gravity greater than material of the tubular shell and the cover, and a plurality of streamlined fins provided on an outer peripheral surface of the upper end part of the tubular shell for vertical descending of the tubular shell; a GPS module provided on the underwater drop type body for receiving GPS position information; an underwater communication transmitter provided upwardly on the cover of the underwater drop type body for transmitting underwater coordinates to a neighboring underwater vehicle while being kept in an exposed state above the sea floor; an underwater acoustic wave receiver provided upwardly on the cover of the underwater drop type body for sensing an acoustic wave of an underwater vehicle while being kept in an exposed state above the sea floor; an underwater acoustic wave transmitter provided upwardly on the cover of the underwater drop type body for generating an acoustic wave to guide access of the underwater vehicle while being kept in an exposed state above the sea floor; a controller for generating and storing the underwater coordinates using GPS position information received by the GPS module, for controlling the underwater communication transmitter to transmit the underwater coordinates, and for controlling the underwater communication transmitter to be changed from inactive state to an active state as the underwater acoustic wave receiver senses the acoustic wave of the underwater vehicle; and a battery provided for supplying electric power to the GPS module, the underwater communication transmitter, the underwater acoustic wave receiver, the underwater acoustic wave transmitter, and the controller and disposed in the lower portion of the inside of the tubular shell.
In the apparatus, a water depth sensor is further provided on the underwater drop type body for sensing water depth information in the water, and the controller generates the underwater coordinates using the GPS position information received by the GPS module and the water depth information sensed by the water depth sensor.
In the apparatus, the controller includes an underwater coordinate generator for generating the underwater coordinates from the GPS position information received by the GPS module and the water depth information sensed by the water depth sensor, an underwater coordinate storage unit for storing the underwater coordinates generated by the underwater coordinate generator, and an underwater coordinate transmission controller for controlling the underwater communication transmitter to transmit the underwater coordinates stored in the underwater coordinate storage unit.
In the apparatus, the underwater communication transmitter is an underwater optical communication transmitter using an optical communication signal.
In the apparatus, an underwater optical communication receiver is further provided on the underwater drop type body for receiving an optical communication signal of the underwater vehicle.
In the apparatus, the underwater acoustic wave transmitter is used together with the underwater optical communication transmitter for transmitting the underwater coordinates to the underwater vehicle.
As described above, after receiving GPS position information from above the surface of the water, the underwater drop type position guiding apparatus according to the present invention is dropped into the water, descended, and automatically fixed very tightly to the sea floor, thereby guiding an accurate position to the underwater vehicle and the like.
In addition, the apparatus of the present invention rapidly descends in an upright position in the water and is installed automatically on the sea floor, without need of a cable to guide the apparatus during the descending process. Accordingly, it is not only easy but also costs less and takes less time for installation of the apparatus.
Particularly, as descending rapidly to the sea floor due to its own weight, the apparatus of the present invention can be installed at an accurate position without being influenced by the tidal current.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a conceptual view of an underwater drop type position guiding apparatus according to an embodiment of the present invention;

FIG. 2 is an enlarged view of an upper end portion of the underwater drop type position guiding apparatus of FIG. 1;

FIG. 3 is a view illustrating a process of dropping the underwater drop type position guiding apparatus of FIG. 1 into water and installing the same on the sea floor; and

FIG. 4 is a view illustrating the use state of the underwater drop type position guiding apparatus of FIG. 1.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily carry out the present invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention in the drawings, portions not related to the description are omitted, and like reference numerals are given to similar portions throughout the specification. Whenever a component is referred to as “including” an element throughout the specification, it is to be understood that the element may include other elements and not exclude any other element unless the context clearly dictates otherwise.
FIG. 1 is a conceptual view of an underwater drop type position guiding apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged view of an upper end portion of the underwater drop type position guiding apparatus of FIG. 1.
The underwater drop type position guiding apparatus 10 according to an embodiment of the present invention is designed to be installed on a sea floor after being dropped into the water, thereby guiding the underwater position of the underwater vehicle to the underwater vehicle and exchanging information with the underwater vehicle through optical communication and acoustic wave communication.
In this case, the underwater vehicle may be an autonomous unmanned underwater vehicle such as the AUV or may be a manned underwater vehicle that is operated directly by a person.
The underwater drop type position guiding apparatus 10 according to the present embodiment includes an underwater drop type body 100, a GPS module 200, a water depth sensor 300, an underwater acoustic wave transceiver 400, an underwater optical communication transceiver 500, a controller 600, and a battery 700.
The underwater drop type body 100 is a cylindrical shape extending vertically and is manufactured to be capable of descending in an upright position to the sea floor. More specifically, the underwater drop type body 100 includes a tubular shell 110 having an empty interior, a head 120 coupled with a lower end part of the tubular shell 110, and a cover 130 coupled with an upper end part of the tubular shell 110.
The tubular shell 110 is for accommodating the controller 600 and the battery 700 therein. Meanwhile, a plurality of streamlined fins 111 is provided at regular intervals on the outer peripheral surface of the upper end of the tubular shell 110.
The streamlined fins 111 are for enabling the underwater drop type body 100 to descend rapidly in an upright position to the sea floor. Here, the streamlined fins 111 are streamlined for generating less fluid resistance in the vertical direction as the name implies and generates resistance to force in the horizontal direction, thereby preventing the underwater drop type body 100 from descending obliquely or upside down.
The head 120 mounted on the lower end part of the tubular shell 110 is made of a non-oxidizing metal having a large specific gravity such as tungsten. The head 120 is a shape of a cone pointing downward so that the underwater drop type body 100 is able to be embedded in a mud layer of the sea floor by its own weight.
The cover 130 is provided at the upper end part of the tubular shell 110. The cover 130 provides places where the underwater acoustic transceiver 400 and the underwater optical communication transceiver 500 are each disposed.
The head 120 and cover 130 seal the lower end part and upper end part of the tubular shell 110, thereby preventing water from flowing into the tubular shell 110.
The underwater drop type body 100 composed of the tubular shell 110, head 120 and cover 130 is designed to have a lower portion where a heavier weight is distributed, whereby the underwater drop type body 100 is capable of descending vertically in an upright position to the sea floor, after being dropped into the water from a ship 20.
The weight distribution of the underwater drop type body 100 is achieved by coupling the head 120, which is made of tungsten having a large specific gravity, with the lower end of the tubular shell 110 and by arranging the relatively heavy battery 700 on the lower side of the tubular shell 110.
The cover 130 is provided with a GPS module 200 for receiving GPS location information from GPS satellites, the water depth sensor 300 for sensing water depth information in the water, and the underwater optical communication transceiver 500 for underwater bidirectional communication with the underwater vehicle. In addition, for sensing an acoustic wave signal of a nearby underwater vehicle and for generating an acoustic wave signal to guide for access of the underwater vehicle, the underwater acoustic wave transceiver 400 is provided.
The GPS module 200, the water depth sensor 300, the underwater acoustic wave transceiver 400, and the underwater optical communication transceiver 500 are provided on the upper end part of the underwater drop type body 100, that is, the cover 130, to face upwards. This is for maintaining the GPS module 200, the water depth sensor 300, the underwater acoustic wave transceiver 400, and the underwater optical communication transceiver 500 in an exposed state above the sea floor, even when the underwater drop type body 100 has deeply embedded in the sea floor.
The GPS module 200 above the surface of the water receives GPS position information from the GPS satellites, and the GPS position information is used to calculate a drop point where the present underwater drop type position guiding apparatus is to be dropped into the water. The GPS module 200 above the surface of the water continuously receives the GPS position information but, once being dropped into the water, is no longer able to receive the GPS position information.
Because the GPS module 200 in the water is unable to receive the GPS position information therethrough, the water depth sensor 300 senses water depth information in a state for which the underwater drop type body 100 has been dropped into the water. The water depth sensor 300 may be a water pressure sensor that measures the water depth by measuring the water pressure.
The water depth information sensed by the water depth sensor 300 will no longer change when the present underwater drop type position guiding apparatus 10 has reached the sea floor and the position thereof has been fixed. That is, by using a status whether the change of the water depth information occurs or not, it is possible to know the water depth information of the position where the present underwater drop type position guiding apparatus 10 is installed. When the GPS position information received by the GPS module 200 and the water depth information sensed by the water depth sensor 300 are used, it is possible to generate underwater coordinates of a plurality of the underwater drop type position guiding apparatuses 10 of the present embodiment installed on the sea floor.
The underwater optical communication transceiver 500 is for communicating with the underwater vehicle using an optical communication signal and for transmitting the underwater coordinates generated using the GPS position information and the water depth information to the underwater vehicle.
The underwater optical communication transceiver 500 includes an underwater optical communication receiver 510 composed of photodiodes and an underwater optical communication transmitter 520 composed of optical LEDs. When the underwater optical communication transceiver 500 is used, a large amount of information may be exchanged at a high speed in the water.
The underwater optical communication receiver 510 enables an optical communication signal of the underwater vehicle to be sensed, thereby receiving information, and the underwater optical communication transmitter 520 enables an optical communication signal to be transmitted to the underwater vehicle, thereby transmitting information. Information exchange in the water using the underwater optical communication transceiver 500 is well known in the conventional art, and thus a detailed description thereof will be omitted.
The underwater optical communication transmitter 520 is an example of an underwater communication transmitter. The underwater optical communication transceiver 500 presented in the present embodiment includes an underwater optical communication transmitter 520 and an underwater optical communication receiver 510, thereby allowing bidirectional information exchange using an optical communication signal.
The communication method is optional and thus may be changed freely. However, whatever change is implemented in the use of the communication method, the underwater optical communication transmitter 520 is to be necessarily included to transmit underwater coordinates to the underwater vehicle.
The underwater acoustic wave transceiver 400 senses an acoustic wave signal generated in the underwater vehicle and generates an acoustic wave signal, thereby guiding the underwater vehicle to approach. In addition, the underwater acoustic wave transceiver 400 is for the communication with the underwater vehicle by using an acoustic wave signal, even when the communication using the underwater optical communication transceiver 500 is not possible. The underwater acoustic wave transceiver 400 of the present embodiment includes an underwater acoustic wave receiver 410 for receiving an acoustic wave signal and an underwater acoustic wave transmitter 420 for generating an acoustic wave signal outwards.
Because the acoustic wave signal is transmitted to a relatively far distance even in turbid water as opposed to the optical communication signal, when the underwater acoustic wave transceiver 400 is used, it is possible to guide an underwater vehicle, which is at a far distance and thus the optical communication signal does not reach the vehicle, with the underwater drop type position guiding apparatus of the present invention. In addition, even when the underwater is turbid and communication using the optical communication signal is not possible, communication with the underwater vehicle may be performed using the underwater acoustic wave transceiver 400.
In the present embodiment, sensing an acoustic wave signal generated by the underwater vehicle, the underwater acoustic wave receiver 410 causes the controller 600, the underwater acoustic wave transmitter 420, and the underwater optical communication transceiver 500 to be activated. That is, the controller 600, the underwater acoustic wave transmitter 420, and the underwater optical communication transceiver 500 are kept inactive until the access of the underwater vehicle is sensed, whereby the limited power stored in the battery 700 is effectively used and thus an operation period of the battery 700 may be extended.
In addition, when the acoustic wave signal of the underwater vehicle is sensed, the underwater acoustic wave transmitter 420 is operated to generate an acoustic wave signal for guiding access of the underwater vehicle.
The controller 600 is provided for generating underwater coordinates using the GPS position information and the water depth information collected from the GPS module 200 and the water depth sensor 300, respectively, and for controlling communication with the underwater vehicle using the underwater optical communication transceiver 500 when the underwater vehicle is sensed in the underwater acoustic wave transceiver 400.
The controller 600 includes an underwater coordinate generator for generating underwater coordinates, in particular, from GPS position information and water depth information, an underwater coordinate storage unit for storing the underwater coordinates generated by the underwater coordinate generator, and an underwater coordinate transmission controller for controlling for the underwater communication transmitter to transmit the underwater coordinates stored in the underwater coordinate storage unit.
The underwater coordinate generator calculates the underwater drop point by software from the GPS position information received by the GPS module 200 (that is, calculates the underwater drop point using the GPS position information until the GPS position information is not available for receiving) or, regarding the arbitrary GPS position information determined by the user's button operation as the underwater drop point, generates the plane coordinates of the underwater coordinates of the underwater drop position guiding apparatus 10.
The process that the underwater coordinate generator calculates the underwater drop point by software will be described in detail.
The GPS module 200 above the surface of the water continuously receives GPS position information from the GPS satellites. However, when the present underwater drop type position guiding apparatus is dropped into the water, the GPS module 200 is no longer able to receive the GPS position information. Therefore, when the GPS position information is no longer received by the GPS module 200, the underwater coordinate generator determines that the present underwater drop type position guiding apparatus has been dropped into the water and may recognize the last received position information as an underwater drop point.
In addition, the underwater coordinate generator determines whether the sensed water depth information is sensed in a state where the present underwater drop type position guiding apparatus has reached the sea floor or not on the basis whether the water depth information sensed by the water depth sensor 300 changes or not, and generates water depth coordinates of the underwater coordinates using the sensed water depth information.
That is, the value of water depth information sensed by the water depth sensor 300 is continuously changed when the present underwater drop type position guiding apparatus is descending in water. However, when the present underwater drop type position guiding apparatus has reached the sea floor, the water depth information sensed by the water depth sensor 300 is no longer changed. Therefore, when the water depth information sensed by the water depth sensor 300 does not change anymore, the underwater coordinate generator determines that the present underwater drop type position guiding apparatus has reached the sea floor and generates the depth coordinates of the underwater coordinates of the present underwater drop type position guiding apparatus using the last sensed water depth information.
The underwater coordinate storage unit stores the plane coordinates and the depth coordinates thus generated as underwater coordinates.
The underwater coordinate transmission controller controls for the underwater optical communication transmitter 520 to transmit the underwater coordinates stored in the underwater coordinate storage unit to the underwater vehicle.
When the underwater coordinates are unable to be transmitted to the underwater vehicle through the underwater optical communication transceiver 500 in the course of the process due to turbid water, the underwater acoustic wave transceiver 400 may be used instead of the underwater optical communication transceiver 500 to transmit the underwater coordinates to the underwater vehicle.
The battery 700 is for supplying power to the GPS module 200, the water depth sensor 300, the underwater acoustic wave transceiver 400, the underwater optical communication transceiver 500, and the controller 600.
Hereinafter, the installation process and use of the underwater drop type position guiding apparatus according to one embodiment of the present invention will be described with reference to the drawings.
FIG. 3 is a view illustrating a process of dropping the underwater drop type position guiding apparatus of FIG. 1 into water and installing the same on the sea floor; and FIG. 4 is a view illustrating the use state of the underwater drop type position guiding apparatus of FIG. 1.
As illustrated in FIG. 3, the underwater drop type position guiding apparatus 10 according to the embodiment of the present invention is carried by a ship 20, and by simply dropping the position guiding apparatuses one by one when passing through an appropriate position, the installation preparation is finished.
The underwater drop type position guiding apparatus 10 of the present embodiment, which has been dropped into the water from the ship 20, descends to the sea floor in an upright position with the head 120 thereof vertically oriented to face downward. The underwater drop type position guiding apparatus 10 descended by own weight thereof becomes to be embedded and fixed to the sea floor.
The underwater drop type position guiding apparatus 10 collects GPS position information above the water surface through the GPS module 200 and senses water depth information through the water depth sensor 300 in the water.
At this time, the present underwater drop type position guiding apparatus 10 generates plane coordinates of the underwater coordinates from the GPS position information, which was collected by the GPS module 200 when the underwater drop type position guiding apparatus 10 was dropped to the water from above the surface of the water and stores the above-generated plane coordinates of the underwater coordinates therein.
In addition, when the present underwater drop type position guiding apparatus 10 becomes fixed to the sea floor, the underwater drop type position guiding apparatus 10 generates water depth coordinates of the underwater coordinates from the water depth information of the water depth sensor 300 and stores the above-generated water depth coordinates of the underwater coordinates therein.
After the underwater coordinates composed of the plane coordinates and the depth coordinates are stored in this way, the present underwater drop type position guiding apparatus 10 remains inactive until receiving an acoustic wave signal of the underwater vehicle 30.
As described above, because the underwater drop type position guiding apparatus 10 according to the embodiment of the present invention may be easily installed on the sea floor merely by being dropped from the ship 20 into the water at a predetermined interval, the installation cost and time may be significantly reduced compared with the conventional method in which a cable is used for installation.
In particular, while the installation method using a cable requires the ship 20 to stop at the installation position, the present underwater drop type position guiding apparatus 10 may be installed simply by being dropped from the ship 20 that is being moved. Accordingly, convenience is highly enhanced.
In addition, because the underwater drop type position guiding apparatus 10 is vertically dropped in an upright position and installed on the sea floor quickly, the effect tidal current influences is reduced compared with a case of installing by hanging on a cable. In other words, the underwater drop type position guiding apparatus 10 may be easily installed not to depart from the planned installation position.
As illustrated in FIG. 4, a plurality of the underwater drop type position guiding apparatuses 10 is installed at certain intervals on the sea floor. Here, each of the underwater drop type position guiding apparatuses 10 is identifiable through a serial number.
The underwater vehicle 30 approaches the underwater drop type position guiding apparatus 10 while generating an acoustic wave signal. When the acoustic wave signal of the underwater vehicle 30 is sensed by the underwater acoustic wave receiver 410 of the underwater drop type position guiding apparatus 10, the underwater optical communication transceiver 500, the controller 600, and the underwater acoustic wave transmitter 420 are changed from the deactivated state to the active state.
Being activated, the underwater acoustic wave transmitter 420 generates an acoustic wave signal, thereby guiding the underwater vehicle 30 to be able to access to a distance communicable through the underwater optical communication transceiver 500.
In addition, being activated, the underwater optical communication transceiver 500 transfers the underwater coordinates stored in the underwater coordinate storage unit of the controller 600 and various information including the serial number for identifying the underwater drop type position guiding apparatus 10 to the underwater vehicle 30.
In this process, information transfer from the underwater vehicle 30 to the underwater drop type position guiding apparatus 10 may also be performed together as needed.
After a transfer of the underwater coordinates and information is completed, the underwater optical communication transceiver 500, the controller 600, and the underwater acoustic wave transmitter 420 become to change again into the inactive state, thereby entering into a state awaiting access of another underwater vehicle.
As described above, because the underwater acoustic wave transmitter 420 and the underwater optical communication transceiver 500 operate only when the acoustic wave signal of the underwater vehicle 30 is sensed by the underwater acoustic wave transceiver 400 as the underwater vehicle 30 approaches a communicable distance, the present underwater drop type position guiding apparatus 10 may be operated for a very long period of time by reducing unnecessary power consumption.
It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.
It is therefore to be understood that the above-described embodiments are illustrative in all aspects but are not restrictive. For example, each component described as a single entity may be implemented being distributed, and components described as being distributed may also be implemented in a combined form.
The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and equivalents thereof are to be construed as being included within the scope of the present invention.

Claims

What is claimed is:

1. An underwater drop type position guiding apparatus for being dropped into water from above a surface of the water and for being installed on a sea floor, the apparatus comprising:

an underwater drop type body including a tubular shell extending vertically, a cover coupled with an upper end part of the tubular shell, a cone-shaped head pointing downward coupled with the lower end part of the tubular shell to be embedded and fixed on the sea floor by own weight thereof and being manufactured with material having a specific gravity greater than material of the tubular shell and the cover, and a plurality of streamlined fins provided on an outer peripheral surface of the upper end part of the tubular shell for vertical descending of the tubular shell;

a GPS module provided on the underwater drop type body for receiving GPS position information;

an underwater communication transmitter provided upwardly on the cover of the underwater drop type body for transmitting underwater coordinates to a neighboring underwater vehicle while being kept in an exposed state above the sea floor;

an underwater acoustic wave receiver provided upwardly on the cover of the underwater drop type body for sensing an acoustic wave of an underwater vehicle while being kept in an exposed state above the sea floor;

an underwater acoustic wave transmitter provided upwardly on the cover of the underwater drop type body for generating an acoustic wave to guide access of the underwater vehicle while being kept in an exposed state above the sea floor;

a controller for generating and storing the underwater coordinates using GPS position information received by the GPS module, for controlling the underwater communication transmitter to transmit the underwater coordinates, and for controlling the underwater communication transmitter to be changed from inactive state to an active state as the underwater acoustic wave receiver senses the acoustic wave of the underwater vehicle; and

a battery provided for supplying electric power to the GPS module, the underwater communication transmitter, the underwater acoustic wave receiver, the underwater acoustic wave transmitter, and the controller and disposed in the lower portion of the inside of the tubular shell.

2. The apparatus of claim 1, wherein a water depth sensor is further provided on the underwater drop type body for sensing water depth information in the water, and the controller generates the underwater coordinates using the GPS position information received by the GPS module and the water depth information sensed by the water depth sensor.

3. The apparatus of claim 2, wherein the controller includes an underwater coordinate generator for generating the underwater coordinates from the GPS position information received by the GPS module and the water depth information sensed by the water depth sensor, an underwater coordinate storage unit for storing the underwater coordinates generated by the underwater coordinate generator, and an underwater coordinate transmission controller for controlling the underwater communication transmitter to transmit the underwater coordinates stored in the underwater coordinate storage unit.

4. The apparatus of claim 1, wherein the underwater communication transmitter is an underwater optical communication transmitter using an optical communication signal.

5. The apparatus of claim 4, wherein an underwater optical communication receiver is further provided on the underwater drop type body for receiving an optical communication signal of the underwater vehicle.

6. The apparatus of claim 5, wherein the underwater acoustic wave transmitter is used together with the underwater optical communication transmitter for transmitting the underwater coordinates to the underwater vehicle.