KR102419238B1 - Marine communication system based on low orbit satellite and unmanned aerial vehicle - Google Patents

Abstract

The present invention relates to a maritime communication system based on a low-orbit satellite and an unmanned aerial vehicle, wherein the maritime communication system according to an embodiment includes at least one marine user, at least one satellite connected to a network operator, and at least one It may include an unmanned aerial vehicle (UAV) that relays communications between a maritime user and at least one satellite.

Description

A maritime communication system based on low-orbit satellites and unmanned aerial vehicles

The present invention relates to a maritime communication system, and more particularly, to a technical idea of constructing a maritime communication system based on a low-orbit satellite and an unmanned aerial vehicle.

The expansion of telecommunication network coverage to global coverage is one of the main goals of next-generation networks, and as a result, coverage of terrestrial communications is expanding at the targeted rate, but maritime communications is not even an efficient communications system for handling data traffic. is not being built.

The demand for maritime communication systems is increasing rapidly due to projects conducted in the deep sea (eg, underwater research, marine life research, marine tourism, etc.).

Specifically, the offshore communication system provides high-connectivity, low latency and higher throughput as maritime activities such as offshore drilling platforms, offshore rescue, emergency operations, and marine aquaculture increase. The demands of marine users are increasing.

Existing maritime communication systems use satellite services or land base stations for communication. International maritime satellites (inmarsat) are responsible for maritime communications, but have the problem that data rates are very low and inefficient for applications.

On the other hand, LEO satellites are emerging as a good source of global coverage, but due to their continuous movement characteristics, it is difficult to maintain a connection with sea users. In addition, due to the high latency caused by the communication between the LEO satellite and the marine user, there is a disadvantage in that it is difficult for the marine user to acquire sensitive information in a short time.

Korean Patent Registration No. 10-1661861, "Monitoring UAV Ad-Hoc Network for PS-LTE Disaster Safety Communication Network" Korean Patent Laid-Open Patent No. 10-2046143, "Unmanned monitoring method and system for drones capable of wireless charging through a charging station"

An object of the present invention is to provide a marine communication system capable of easily integrating terrestrial communication and maritime communication using a low-orbit satellite and an unmanned aerial vehicle.

In addition, an object of the present invention is to provide a marine communication system capable of performing communication between a marine user and a satellite with low latency through relay using an unmanned aerial vehicle.

In addition, the present invention is to provide a marine communication system that can easily wirelessly charge an unmanned aerial vehicle at sea.

A maritime communication system according to an embodiment of the present invention is an unmanned aerial vehicle that relays communication between at least one sea user, at least one satellite connected to a network operator, and at least one sea user and at least one satellite. unmanned aerial vehicles (UAVs).

According to one side, the at least one sea user may include a ship located in the sea, and the at least one satellite may include a low earth orbit (LEO) satellite located at a low altitude of 1,000 km to 1,400 km.

According to one side, the unmanned aerial vehicle may monitor a communication state performed between at least one sea user and at least one satellite.

According to one side, the unmanned aerial vehicle may receive the location information of a user equipped with a charging station among at least one marine user at every preset period.

According to one side, when the power of the provided battery is below a preset threshold, the unmanned aerial vehicle may fly to the location of the user equipped with the charging station based on the location information, and perform wireless charging at the location where the charging station is moved. have.

The unmanned aerial vehicle of the maritime communication system according to an embodiment includes a user connection unit connecting at least one sea user and a network, a satellite connection unit connecting at least one satellite and a network, and communication between at least one sea user and at least one satellite. It may include a communication control unit for relaying the relay and monitoring the state of the relayed communication.

According to one side, the at least one sea user may include a ship located in the sea, and the at least one satellite may include a low earth orbit (LEO) satellite located at a low altitude of 1,000 km to 1,400 km.

According to one side, the user connection unit may include a multiple-input and multiple-output (MIMO) directional antenna, and may connect at least one marine user and a network through the provided MIMO directional antenna.

According to one side, the user connection unit may receive the location information of a user equipped with a charging station among at least one marine user at every preset period.

According to one side, the unmanned aerial vehicle of the maritime communication system may further include an aircraft control unit that generates a flight control signal for flight movement to a location corresponding to the location information when the power of the provided battery is less than or equal to a preset threshold value. have.

According to one embodiment, the present invention can easily integrate terrestrial communication and maritime communication using a low-orbit satellite and an unmanned aerial vehicle.

According to an embodiment, the present invention can perform communication between a marine user and a satellite with low latency through relay using an unmanned aerial vehicle.

According to one embodiment, the present invention can easily wirelessly charge an unmanned aerial vehicle at sea.

1 is a view for explaining a maritime communication system according to an embodiment.
2 is a view for explaining an unmanned aerial vehicle provided in the maritime communication system according to an embodiment.
3 is a diagram for explaining an implementation example of a maritime communication system according to an embodiment.
4A to 4C are diagrams for explaining an example of wirelessly charging an unmanned aerial vehicle of a maritime communication system according to an embodiment.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed herein are only exemplified for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiment according to the concept of the present invention These may be embodied in various forms and are not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention may have various changes and may have various forms, the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes changes, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one element from another, for example, without departing from the scope of the present invention, a first element may be named a second element, and similar The second component may also be referred to as the first component.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle. Expressions describing the relationship between elements, for example, “between” and “between” or “directly adjacent to”, etc. should be interpreted similarly.

The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, and includes one or more other features or numbers, It should be understood that the possibility of the presence or addition of steps, operations, components, parts or combinations thereof is not precluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference numerals in each figure indicate like elements.

1 is a diagram for explaining a maritime communication system according to an embodiment.

Referring to FIG. 1 , the maritime communication system 100 according to an embodiment can easily integrate terrestrial communication and maritime communication using a low-orbit satellite and an unmanned aerial vehicle.

In addition, the marine communication system 100 may relay communication between the marine user and the satellite with low latency using an unmanned aerial vehicle.

In addition, the maritime communication system 100 can easily wirelessly charge the unmanned aerial vehicle at sea.

To this end, the maritime communication system 100 according to an embodiment may include at least one maritime user 110 , an unmanned aerial vehicle (UAV) 120 , and at least one satellite 130 .

According to one side, at least one marine user 110 may include a ship located in the sea, and the at least one satellite 130 may include a low earth orbit (LEO) satellite located at a low altitude of 1,000 km to 1,400 km. have.

At least one satellite 130 according to an embodiment may be connected to a network operator.

For example, the network operator is an organization responsible for network operation, and more specifically, may refer to a device such as a server that provides overall control and communication services of the maritime communication system 100 .

The unmanned aerial vehicle 120 according to an embodiment may relay communication between the at least one marine user 110 and the at least one satellite 130 .

According to one side, the unmanned aerial vehicle 120 may monitor the communication state performed between the at least one sea user 110 and the at least one satellite 130 .

For example, the unmanned aerial vehicle 120 monitors a communication state with the at least one sea user 110 , and based on the monitoring result, the utility of the network formed between the at least one sea user 110 and the unmanned aerial vehicle 120 . (utility) can be optimized.

Specifically, the unmanned aerial vehicle 120 includes a free space path loss value (PL _FS ) between each of at least one sea user forming a network and the unmanned aerial vehicle 120 , and a free space path of each sea user. The utility of the network may be maximized based on the gain value g _i of the sub carrier corresponding to the loss value PL.

According to one side, the unmanned aerial vehicle 120 may receive the location information of a user equipped with a charging station among at least one marine user 110 at every preset period.

In addition, when the power of the provided battery is less than or equal to a preset threshold, the unmanned aerial vehicle 120 flies to the location of the user equipped with the charging station based on the location information of the user equipped with the charging station, and flies Wireless charging can be performed through a charging station at the user's location.

According to one side, the unmanned aerial vehicle 120 may transmit a wireless charging request signal to the network operator and receive a wireless charging feedback signal corresponding thereto when the power of the provided battery is less than or equal to a preset threshold value. In addition, upon receiving the wireless charging feedback signal, the unmanned aerial vehicle 120 may perform a flight operation to a location of a user equipped with a charging station.

When the network operator receives the wireless charging request signal, it readjusts the positions of the unmanned aerial vehicles located within a preset distance from the unmanned aerial vehicle 120 that transmitted the wireless charging request signal to the absence of the unmanned aerial vehicle 120 that has transmitted the wireless charging request signal. Accordingly, it is possible to minimize the gap in the communication relay.

In addition, when the charging of the unmanned aerial vehicle 120 that has transmitted the wireless charging request signal is completed, the network operator may re-adjust the positions of the charged unmanned aerial vehicle 120 and the unmanned aerial vehicle located within a preset distance.

An example of wirelessly charging an unmanned aerial vehicle will be described in more detail later with reference to FIGS. 4A to 4C.

2 is a view for explaining an unmanned aerial vehicle provided in the maritime communication system according to an embodiment.

In other words, FIG. 2 relates to an example of an unmanned aerial vehicle provided in the maritime communication system described with reference to FIG. 1 , and descriptions that overlap with those described with reference to FIG. 1 among the contents described with reference to FIG. 2 will be omitted.

Referring to FIG. 2 , the unmanned aerial vehicle 200 according to an embodiment may include a user connection unit 210 , a communication control unit 220 , a satellite connection unit 230 , and an airplane control unit 240 .

The user connection unit 210 according to an embodiment may connect at least one marine user and a network, and the satellite connection unit 230 according to an embodiment may connect at least one satellite and a network.

According to one side, the at least one sea user may include a ship located in the sea, and the at least one satellite may include a low earth orbit (LEO) satellite located at a low altitude of 1,000 km to 1,400 km.

According to one side, the user connection unit 210 may include a multiple-input and multiple-output (MIMO) directional antenna, and may connect at least one marine user and a network through the provided MIMO directional antenna.

Specifically, in consideration of marine user characteristics that are rarely distributed in the sea, the user connection unit 210 may communicate with at least one marine user through a MIMO directional antenna. In other words, the user connection unit 210 may minimize communication interference between maritime users through coordinated communication between points based on the MIMO directional antenna.

The communication control unit 220 according to an embodiment may relay communication between at least one marine user and at least one satellite, and monitor the state of the relayed communication.

For example, the communication control unit 220 may monitor a communication state with at least one sea user, and optimize the utility of a network formed between the at least one sea user and the unmanned aerial vehicle based on the monitoring result. .

Specifically, the communication control unit 220 performs a free space path loss (PL _FS ) between the N-th (here, N is a positive integer) maritime user and the unmanned aerial vehicle 200 forming the network. It can be calculated through Equation 1.

[Equation 1]

Here, f is the carrier frequency of the channel, U is the set of sea users (U = 1, 2, ..., N), and d _U is the distance between the unmanned aerial vehicle and each sea user.

Also, the communication control unit 220 may calculate a gain value g _i of a sub-carrier corresponding to the free space path loss value PL of each sea user through Equation 2 below.

[Equation 2]

Next, the communication control unit 220 maximizes the utility of the network through the operation of Equation 3 below based on the calculated free space path loss value (PL _FS ) and the calculated subcarrier gain value (g _i ) )can do.

[Equation 3]

Here, (a) of Equation 3 is an equation that maximizes the utility of the network, P is a control parameter of each sea user, and (b) of Equation 3 is each according to a channel condition Represents a constraint on the proportional distribution of power of marine users.

(c) of Equation 3 represents a constraint to ensure the maximum power limit of the unmanned aerial vehicle 200, and (d) of Equation 3 is the Represents a constraint on a certain percentage of power.

That is, the communication control unit 220 may maximize the utility of the network through the operation of Equation 3 based on the karush-kuhn-tucker (KKT) condition.

According to one side, the user connection unit 210 may receive the location information of a user equipped with a charging station among at least one marine user at every preset period.

In addition, when the power of the battery provided in the unmanned aerial vehicle 200 is less than or equal to a preset threshold, the vehicle control unit 240 provides a flight control signal for flight to a location corresponding to the location information of the user equipped with the charging station. can create

Specifically, when the power of the battery is less than or equal to a preset threshold, the communication control unit 220 may transmit a wireless charging request signal to the network operator and receive a wireless charging feedback signal corresponding thereto, and the vehicle control unit 240 may When the wireless charging feedback signal is received, a flight control signal may be generated to control the flight movement of the unmanned aerial vehicle 200 .

On the other hand, when the network operator receives the wireless charging request signal, the unmanned aerial vehicle 200 that transmits the wireless charging request signal by re-adjusting the positions of the unmanned aerial vehicles located within a preset distance from the unmanned aerial vehicle 200 that has transmitted the wireless charging request signal It is possible to minimize the gap in communication relay due to the absence.

In addition, when the charging of the unmanned aerial vehicle 200 that has transmitted the wireless charging request signal is completed, the network operator may re-adjust the positions of the charged unmanned aerial vehicle 200 and the unmanned aerial vehicle located within a preset distance.

3 is a diagram for explaining an implementation example of a maritime communication system according to an embodiment.

In other words, FIG. 3 relates to an implementation example of a maritime communication system according to an embodiment described with reference to FIGS. 1 and 2 , and overlaps with the content described with reference to FIGS. 1 and 2 among the contents described with reference to FIG. 3 . A description will be omitted.

Referring to FIG. 3 , the maritime communication system according to an embodiment may include at least one satellite 301 , at least one sea user 312 , 315 , 316 , and at least one unmanned aerial vehicle 303 , 307 . have.

In addition, the maritime communication system 300 according to an embodiment includes a network operator 318 , at least one island base station 314 and at least one offshore base station 320 . ) may be further included.

For example, the at least one satellite 301 may include a low earth orbit (LEO) satellite located at a low altitude of 1,000 km to 1,400 km. That is, at least one satellite 301 may form a low earth orbit satellite constellation (LEO).

In addition, at least one marine user 312 , 315 , 316 may include a vessel located in the sea.

Specifically, the LEO satellite 301 can support worldwide expansion of communication range using the network operator 318 . However, due to the mobility characteristics of the LEO satellite 301, time intervals are generated in communication with the maritime user 316, and thus continuous communication connection may be restricted.

Accordingly, the maritime communication system 300 according to an embodiment can guarantee a continuous communication service between the LEO satellite 301 and the marine user 316 through communication relay using the unmanned aerial vehicle 307 .

The unmanned aerial vehicle 307 may provide a direct line of sight (LOS) connection to the maritime user 316 as an autonomous vehicle, and may perform a backhauling role through this.

The network operator 318 performs a fast hand-off for each of the at least one maritime user 312 , 315 , 316 based on location information of the at least one maritime user 312 , 315 , 316 based on GPS. function can be provided.

In other words, the network operator 318 assigns each of the maritime users 312, 315, and 316 to the unmanned aerial vehicle 307, the island base station 314 and the offshore base station based on the location information of the maritime users 312, 315, 316. 320) may be connected to a corresponding relay means.

More specifically, the LEO satellite 301 may orbit around the world from an altitude of 1,000 km to 1,400 km.

OISL (optical inter satellite link) 302 is a channel that connects LEO satellite groups providing various applications, and each LEO satellite 301 communicates time synchronization information with each other through OISL 302 to enhance orbital position information. can be exchanged

The relay unmanned aerial vehicle 303 may serve to relay communication performed between the island base station 314 and the LEO satellite 301 to ensure connectivity with the base station.

A relay backhaul link 304 is formed between the relay unmanned aerial vehicle 303 (ie, backhaul) and the LEO satellite 301 that relay communication performed between the island base station 314 and the LEO satellite 301 . It may mean a channel.

A high altitude platform (HAP) 305 may refer to an area in which unmanned aerial vehicles 303 and 307 relay maritime communication services.

The service provider UAV backhaul link 306 may refer to a channel through which the service providing unmanned aerial vehicle 307 relaying information from the maritime user is connected to the LEO satellite 301 .

The service providing unmanned aerial vehicle 307 may guarantee communication connection with an end user (sea user) and a request for waiting time, and may provide various applications to sea users and monitor the sea.

The feeder link 308 may refer to a channel formed between the LEO satellite 301 and a feeder link station 311 .

The island base station backhaul link 309 may refer to a channel formed between the relay unmanned aerial vehicle 303 hovering for service provision and the island base station 314 .

The beamforming signal 310 of the unmanned aerial vehicle may refer to a beamforming signal transmitted from the service providing unmanned aerial vehicle 307 in order to reduce additional spectrum consumption due to a lack of spectrum.

The feeder link station 311 may process all information provided from the LEO satellite 301 through the feeder link 308 to ensure high connectivity and real-time service of the system.

The offshore base station user 312 is a marine user located close to a predetermined distance from the coast, and may receive a communication service through the offshore base station 320 instead of the service providing unmanned aerial vehicle 307 in order to receive the communication service.

The satellite gateway 313 is a fiber optics wired link connecting the feeder link station 311 and the network operator 318, and the LEO satellite 301 is a feeder link 308, a feeder link station 311 and It may be connected to the network operator 318 through the satellite gateway 313 .

The island base station 314 is a means for providing more and smoother communication services at sea, and can provide communication services to the island base station users 315 through the relay unmanned aerial vehicle 303 .

The island base station user 315 is a marine user located close to a predetermined distance from the island base station 314, and in order to receive a communication service, a communication service will be provided through the island base station 314 rather than the service providing unmanned aerial vehicle 307. can

The unmanned aerial vehicle user 316 may mean a marine user who is directly provided with a communication relay service from the service providing unmanned aerial vehicle 307 .

The fiber link 317 may refer to a channel formed between the network operator 318 and the nearby base station 320 .

The network operator 318 is an organization responsible for the operation of the network of marine users, and more specifically, may refer to an organization that provides overall control and communication services of the maritime communication system 300 . For example, the network operator 318 may control a communication relay function and wireless charging of each of the unmanned aerial vehicles (303, 307) through the unmanned aerial vehicle (303, 307).

The offshore base station 320 may be connected to the network operator 318 through a fiber link 317 to provide a communication service to the offshore base station user 312 .

4A to 4C are diagrams for explaining an example of wirelessly charging an unmanned aerial vehicle of a maritime communication system according to an embodiment.

4A to 4C , the maritime communication system according to an embodiment may include at least one unmanned aerial vehicle (UAV-A and UAV-B).

According to one side, each of the unmanned aerial vehicles (UAV-A and UAV-B) may receive the location information of a user equipped with a charging station among at least one marine user at every preset period.

In addition, when the power of each of the unmanned aerial vehicles (UAV-A and UAV-B) is less than or equal to a preset threshold value, based on the location information of the user equipped with the charging station, the location of the user equipped with the charging station is returned. It can fly and move, and unmanned aerial vehicles (UAV-A and UAV-B) that have moved can perform wireless charging using a charging station.

For example, a user equipped with a charging station can guide the unmanned aerial vehicles (UAV-A and UAV-B) to the location of the charging station when the unmanned aerial vehicles (UAV-A and UAV-B) are adjacent within a preset threshold distance. It can transmit control signals for unmanned aerial vehicles (UAV-A and UAV-B).

In addition, a user equipped with a charging station can charge the battery of the unmanned aerial vehicle (UAV-A and UAV-B) through wireless charging when the unmanned aerial vehicle (UAV-A and UAV-B) reaches the location of the charging station. .

According to one side, each of the unmanned aerial vehicles (UAV-A and UAV-B) transmits a wireless charging request signal to the network operator when the power of the provided battery is less than or equal to a preset threshold, and receives a wireless charging feedback signal corresponding thereto can do.

In addition, each of the unmanned aerial vehicles (UAV-A and UAV-B) may perform a flight operation to the location of the user equipped with the charging station upon receiving the wireless charging feedback signal.

Upon receiving the wireless charging request signal, the network operator readjusts the positions of the unmanned aerial vehicles located within a preset distance from the unmanned aerial vehicle (UAV-A and UAV-B) that transmitted the wireless charging request signal, and transmits the wireless charging request signal. It is possible to minimize the gap in communication relay due to the absence of (UAV-A and UAV-B).

In addition, when the charging of the unmanned aerial vehicle (UAV-A and UAV-B) that has transmitted the wireless charging request signal is completed, the network operator can control the fully charged unmanned aerial vehicle (UAV-A and UAV-B) and the unmanned aerial vehicle located within a preset distance. You can reposition them.

Specifically, in step 410, each of the unmanned aerial vehicles (UAV-A and UAV-B) may receive the location information of the user equipped with the charging station at every preset period.

In addition, the unmanned aerial vehicle (UAV-A), when the power of the provided battery is less than or equal to a preset threshold value, based on the location information of the user equipped with the charging station to fly to the location of the user equipped with the wireless charging station charging can be performed.

When the wireless charging of the unmanned aerial vehicle (UAV-A) is completed, the network operator can fly and move the unmanned aerial vehicle (UAV-A) to the current location of the unmanned aerial vehicle (UAV-B) requiring wireless charging.

In step 420, the unmanned aerial vehicle (UAV-A) whose wireless charging has been completed replaces the unmanned aerial vehicle (UAV-B) requiring wireless charging when the power of the provided battery is below a preset threshold value and relays communication between the sea user and the satellite. It can be performed, and an unmanned aerial vehicle (UAV-B) requiring wireless charging may receive location information of a user equipped with a charging station.

In step 430, the unmanned aerial vehicle (UAV-B) requiring wireless charging may perform wireless charging by flying to the location of the user equipped with the wireless charging station based on the location information of the user equipped with the charging station.

After all, by using the present invention, it is possible to easily integrate terrestrial communication and maritime communication using a low-orbit satellite and an unmanned aerial vehicle.

In addition, through relay using the unmanned aerial vehicle, communication between the sea user and the satellite can be performed with low latency, and the unmanned aerial vehicle can be easily wirelessly charged at sea.

Although the embodiments have been described with reference to the limited drawings as described above, various modifications and variations are possible by those skilled in the art from the above description. For example, the described techniques are performed in an order different from the described method, and/or the described components, such as devices, structures, devices, circuits, etc., are combined or combined in a different form than the described methods, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

100: maritime communication system 110: maritime users
120: unmanned aerial vehicle 130: satellite

Claims (10)

at least one maritime user;
at least one satellite associated with a network operator; and
An unmanned aerial vehicle (UAV) relaying communication between the at least one sea user and the at least one satellite
including,
The unmanned aerial vehicle is
Receiving the location information of a user equipped with a charging station among the at least one marine user at every preset period
maritime communication system. According to claim 1,
the at least one maritime user,
including ships located at sea;
the at least one satellite,
Including low earth orbit (LEO) satellites located at low altitudes of 1,000 km to 1,400 km
maritime communication system. According to claim 1,
The unmanned aerial vehicle is
monitoring a communication status performed between the at least one maritime user and the at least one satellite
maritime communication system. delete According to claim 1,
The unmanned aerial vehicle is
When the power of the provided battery is less than or equal to a preset threshold value, based on the location information, the charging station moves to the location of the user equipped with the charging station, and wireless charging is performed at the flying location.
maritime communication system. a user connection unit for connecting at least one maritime user and a network;
a satellite connection unit connecting the network with at least one satellite; and
A communication control unit for relaying communication between the at least one marine user and the at least one satellite, and monitoring a state of the relayed communication
including,
The user connection unit,
Receiving the location information of a user equipped with a charging station among the at least one marine user at every preset period
Unmanned aerial vehicle in maritime communication system. 7. The method of claim 6,
the at least one maritime user,
including ships located at sea;
the at least one satellite,
Including low earth orbit (LEO) satellites located at low altitudes of 1,000 km to 1,400 km
Unmanned aerial vehicle in maritime communication system. 7. The method of claim 6,
The user connection unit,
It has a MIMO (multiple-input and multiple-output) directional antenna, and connects the at least one maritime user and a network through the provided MIMO directional antenna.
Unmanned aerial vehicle in maritime communication system. delete 7. The method of claim 6,
When the power of the provided battery is less than or equal to a preset threshold, the aircraft control unit generates a flight control signal for flight movement to a location corresponding to the location information.
An unmanned aerial vehicle of a maritime communication system further comprising a.

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