Communication control system and communication control method

Abstract

To make it possible to safely take off and land on without interrupting wireless communication when taking off and landing on a departure and arrival port.SOLUTION: A communication control system for controlling communication of an aircraft that is taking off and landing on, includes: a control system that has an arithmetic device for executing predetermined processing and a storage device connected to the arithmetic device; and the aircraft that communicates with the control system via a base station. The control system stores radio wave maps representing a position and a flight altitude of the aircraft and radio wave quality for each base station, refers to the radio wave maps at a plurality of altitudes, and selects a base station whose radio quality is preferable on a departure and arrival route of a departure and arrival port.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a communication control system for controlling communication between an aircraft and a control system, and particularly to a communication control method during takeoff and landing.

Background Art

[0002] In recent years, a system for transporting luggage using an aircraft called a drone that takes off and lands vertically with respect to the landing surface has been proposed. In the transport system using a drone, data representing the flight planned path on the horizontal plane of the drone is input, a height reference value representing the elevation of the ground surface under each of a plurality of positions on the flight planned path is acquired, and the value obtained by adding the flight altitude to the height reference value of the position is used as the altitude data of the flight planned path, so that the flight planned path can be flown without colliding with obstacles.

[0003] In such a transport system using a drone, it is important that many drones can efficiently arrive at the destination and take off and land, and a control system such as that for an airplane is required. Communication between an aircraft such as a drone and a control system is performed wirelessly to confirm movement along the flight planned path and to adjust the movement such as route change.

[0004] As background art in the technical field, there are the following prior arts. There are Patent Document 1 (International Publication No. 2016 / 190793) and Patent Document 2 (International Publication No. 2018 / 159794). Patent Document 1 describes a radio base station including a reception state acquisition unit that acquires at least one of an interference level in a plurality of cells including a self-cell to which a user device is connected or reception communication quality at the user device in the plurality of cells, and a power control unit that restricts transmission power when the interference level or reception communication quality in the plurality of cells acquired by the reception state acquisition unit is within a predetermined range.

[0005] Further, Patent Document 2 describes a mobile adjustment device that moves according to a plan along a route via a wireless communication network and simultaneously adjusts the movement of a wireless transceiver that communicates for an application having service requirements in the wireless communication network. The wireless communication network includes cells, and the mobile adjustment device acquires wireless network condition data regarding a group of cells including the current cell in which the wireless transceiver is located and a plurality of adjacent cells to which the wireless transceiver can move, analyzes the wireless network condition data regarding achieving the service requirements of the application, and is operable to adjust the planned movement when the analysis indicates that this adjustment will improve the achievement of the service requirements.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] As described above, Patent Document 1 describes that an aircraft moves according to a plan along a route via a wireless communication network, analyzes wireless communication conditions in the current location and the wireless communication area on the next moving route, and flies while adjusting the moving route so as to satisfy the wireless quality required by an application mounted on the aircraft. However, for selecting an optimal cell from a plurality of cells, it is not suitable for movement in the height direction within the same cell, such as at takeoff and landing. When the communication environment deteriorates within the same cell or when a plurality of connectable base stations are found, a handover process for switching the connection to the optimal base station occurs. During the handover process, communication is interrupted, so there is a problem that communication cannot be performed at takeoff and landing.

[0008] Further, Patent Document 2 describes managing radio reception levels and interference levels by altitude and controlling the optimal base station and transmission power at a certain altitude. However, when moving in the height direction, it does not consider the total radio communication quality from the landing start location where descent begins to the departure / arrival port which is the landing location, or, in the case of takeoff, from the departure / arrival port to the altitude at which lateral flight begins. Therefore, there is a problem that handover processing, which is a switch to the optimal base station, occurs and communication is interrupted.

[0009] Also, since radio interference from above the aircraft is not considered at all, when an aircraft is descending, a change in the radio environment may occur due to the influence of a plurality of aircraft waiting above it. After starting descent for landing, if the assumed radio environment deteriorates, there is a problem that handover processing, which is a switch to the optimal base station, occurs and communication is interrupted.

[0010] In view of such problems, an object of the present invention is to provide a system that enables safe takeoff and landing without interrupting wireless communication when landing from above to the departure / arrival port and when taking off from the departure / arrival port to above.

Means for Solving the Problems

[0011] A typical example of the invention disclosed in the present application is as follows. That is, a communication control system for controlling the communication of an aircraft for takeoff and landing, comprising a control system having an arithmetic unit that executes predetermined processing and a storage device connected to the arithmetic unit, and an aircraft that communicates with the control system via a base station. The control system stores a radio map representing the position, flight altitude of the aircraft, and radio quality for each base station, and selects a base station with good radio quality on the takeoff / landing route at the departure / arrival port by referring to radio maps at a plurality of altitudes.

Effects of the Invention

[0012] According to one aspect of the present invention, when taking off and landing at the takeoff / landing port of an aircraft, it can fly safely without interruption of wireless communication. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0014] In an arrival / departure system including an aircraft 101 and a control system 103, the control system 103 manages the flight plan, position, altitude, and radio quality status of the aircraft 101, generates a radio map based on the flight path information from the current altitude of the aircraft 101 to the arrival / departure port 102 and the radio quality for each altitude, selects an optimal base station based on the generated radio map, and instructs the aircraft 101. Further, the control system 103 applies retransmission control of radio data (radio packets) including the same content and consecutive transmission control for continuously transmitting the same packet a plurality of times to the communication between the aircraft 101 and the control system 103 according to the radio quality determined based on the radio map, thereby improving the reliability of wireless communication. Furthermore, the aircraft 101 has a function for adjusting the antenna directivity, a function for controlling the mechanism for adjusting the antenna directivity, and a function for enabling fixed connection to a specific base station in order to maintain connection with the optimal base station at the time of arrival / departure at the arrival / departure port.

[0015] <Example 1> Hereinafter, the configuration of Example 1 of the present invention will be described with reference to FIGS. 1 to 7, and the processing of this example will be described with reference to FIGS. 8 and 9. Note that the present invention is not limited to the following examples, and modifications and application examples are included in the scope of the present invention within the technical idea of the present invention.

[0016] FIG. 1 is a diagram showing a schematic configuration of the system of Example 1 of the present invention.

[0017] The system of Example 1 includes an aircraft 101, an arrival / departure port 102, a control system 103, and base stations 104 and 105.

[0018] The aircraft 101 is an aircraft capable of flying vertically like a drone, for example, an aircraft capable of vertically taking off and landing such as a drone or an eVTOL. Note that the present invention is not limited to an unmanned drone, and can also be applied to other forms of aircraft capable of vertically taking off and landing, for example, a manned aircraft, and is not limited to the shape of the aircraft, or forms such as manned / unmanned, automatic flight / pilot flight.

[0019] The takeoff and landing port 102 is composed of a takeoff and landing location 106 where the aircraft takes off and lands, and a control system 103 that controls the flight of the departing and arriving aircraft 101. In the vicinity of the takeoff and landing port 102, a base station A 104 and a base station B 105 for communicating with the takeoff and landing location 106 and the departing and arriving aircraft 101 are provided.

[0020] In FIG. 1, the takeoff and landing port 102 includes one takeoff and landing location 106, but may include a plurality of takeoff and landing locations 106.

[0021] The control system 103 is connected to the takeoff and landing port 102 including the takeoff and landing location 106, the base station A 104, and the base station B 105, and manages the takeoff and landing order and timing of a plurality of aircraft 101. In addition, the control system 103 manages the selection of the base station that becomes the communication establishment destination and the communication quality during the movement between the aircraft 101 and the takeoff and landing location 106 in order to stably communicate between the aircraft 101 and the control system 103.

[0022] The base station A 104 is a wireless facility for the aircraft 101 and the control system 103 to communicate, and is a base station of a communication carrier that provides a wireless communication infrastructure such as LTE or 5G, or a communication base station of a self-constructed wireless network such as a wireless LAN, private LTE, or local 5G. Note that the wireless method of the base station A 104 is not limited, and any wireless facility or device capable of realizing wireless communication between the control system 103 side and the aircraft 101 may be used. Although the base station A 104 has been described above, the base station B 105 has the same configuration.

[0023] FIG. 2 is a block diagram showing the configuration of the aircraft 101 and the control system 103 of the first embodiment.

[0024] FIG. 2 shows a typical configuration of the aircraft 101. Although not shown in FIG. 2, when there are a plurality of aircraft 101, each aircraft 101 has the same configuration.

[0025] The aircraft 101 includes a CPU 201, a flight control device 202, a positioning device 203, a directional adjustment wireless communication device A 204-a1, an antenna 204-a2, a directional adjustment wireless communication device B 204-b1, an antenna 204-b2, a wireless information storage device 205, and a communication control device 206.

[0026] The CPU 201 is an arithmetic device that controls the execution of all functions for controlling the aircraft.

[0027] The flight control device 202 is a device that controls the orientation of the aircraft body, flight speed, etc. according to a flight control program executed by the CPU 201.

[0028] The positioning device 203 is a device that measures the current position information of the aircraft 101 flying. For example, a positioning system such as GNSS (Global Navigation Satellite System) can be used. The positioning device 203 may be in other forms or methods as long as it can acquire the position information of the aircraft 101 with high precision. When the positioning device 203 is GNSS, the positioning device 203 can provide accurate time information.

[0029] The directional adjustment wireless communication device A 204-a1 is a wireless device having a function of adjusting the directivity of the connected antenna 204-a2. The antenna 204-a2 has both an omnidirectional characteristic of transmitting and receiving radio waves with uniform intensity in a 360-degree space and a directional characteristic of transmitting and receiving radio waves in a specific direction. For example, it can be realized by mechanically changing the direction of a directional antenna, an adaptive array antenna with electrically changeable directivity, implementing both an omnidirectional antenna and a directional antenna, etc. Also, the directional adjustment wireless communication device A 204-a1 is a wireless device having a transmission and reception function corresponding to wireless communication methods such as LTE used as a mobile network, 5G, and WiFi used as a private wireless network.

[0030] The directional adjustment wireless communication device B204-b1 has a transmission / reception function according to the wireless system and a function of adjusting the directivity of the antenna 204-b2, similar to the directional adjustment wireless communication device A204-a1. The directional adjustment wireless communication device A204-a1 and the directional adjustment wireless communication device B204-b1 may use the same wireless system or different wireless systems. Even if they use the same wireless system, for example, they may be connection services to mobile networks provided by different communication carriers. Various combinations can be adopted for the communication systems of the directional adjustment wireless communication device A204-a1 and the directional adjustment wireless communication device B204-b1.

[0031] The wireless information storage device 205 stores wireless information together with the position information and time information provided by the positioning device 203. The wireless information stored in the wireless information storage device 205 is KPIs (Key Performance Indicators) of wireless communication such as the intensity of radio waves received by the aircraft 101 from the base stations 104 and 105, interference information, communication speed, and packet error rate.

[0032] The communication control device 206 is composed of a communication quality measurement unit 207, a retransmission / consecutive transmission control unit 208, a route control unit 209, and an antenna directivity adjustment unit 210, and is a device that controls communication.

[0033] The communication quality measurement unit 207 measures the intensity of radio waves received by the aircraft 101 from the base stations 104 and 105, the communication success probability during transmission to the base stations 104 and 105, and the like.

[0034] When the base stations 104 and 105 fail to receive the wireless data (wireless packets) transmitted by the flying object 101, the retransmission and continuous transmission control unit 208 provides communication reliability improvement functions such as a retransmission function that retransmits the unreached data to improve the communication success probability, and a continuous transmission function that transmits the same data multiple times to improve the communication success probability by having at least one piece of data received by the base station. Also, when the base stations 104 and 105 receive the same data due to the retransmission function and continuous transmission function they have, they have functions such as discarding all but one. To implement the retransmission function and continuous transmission function, for example, it is advisable to use a data structure with a unique sequence number added, but in this embodiment, it is only necessary to be able to determine the same data, and various configurations and implementation means can be adopted.

[0035] The path control unit 209 determines the communication path so that the data transmitted by the flying object 101 is transmitted from either one or both of the plurality of wireless communication devices 204-a1 and 204-b1 that the flying object 101 has. For example, by selecting one highly reliable communication method or multiplexing, a path that can improve the communication reliability is determined. Similar to the retransmission and continuous transmission control unit 208, the path control unit 209 can adopt various communication path determination methods.

[0036] The antenna directivity adjustment unit 210 transmits a control command for adjusting the direction of the antenna 204-a2 to the directivity adjustment wireless communication device A204-a1, and transmits a control command for adjusting the direction of the antenna 204-b2 to the directivity adjustment wireless communication device B204-b1. The adjustment of the antenna direction can be achieved by a mechanical mechanism such as a motor, or by a method of selecting one suitable direction from a plurality of directional antennas, or by using an adaptive array antenna, etc., and various directivity adjustment methods can be adopted.

[0037] The control system 103 includes a path planning device 211, a wireless information management device 212, a communication device 213, a wireless information DB 214, and a base station A 104.

[0038] The path planning device 211 plans the flight path to the departure / arrival port 102 of the flying object 101.

[0039] The wireless information management device 212 includes a wireless information registration unit 215, a wireless information update unit 216, a wireless information acquisition unit 217, and a radio map generation unit 218. The wireless information registration unit 215 provides a user interface (see FIG. 3) for registering the position, altitude, and wireless information of the aircraft in the wireless information DB 214. The wireless information update unit 216 updates or adds the already registered wireless information to the latest wireless information. When recording and managing one piece of wireless information for each position and altitude, it is advisable to update the wireless information. When recording and managing a plurality of data in time-series data for the same position and altitude, it is advisable to add and register the wireless information. The wireless information acquisition unit 217 acquires the information recorded in the wireless information DB 214. The radio map generation unit 218 calculates a value to be registered in the radio map from the wireless information managed for each base station according to the position and altitude, or the position, altitude, and time, from the flight route generated and managed by the route planning device 211, the position of the aircraft, the base station to be connected, and the wireless information acquired by the wireless information acquisition unit 217 from the wireless information DB 214 at the position and altitude. For example, the value to be registered in the radio map can be calculated by processing such as adding a plurality of wireless information managed for each altitude according to the flight route.

[0040] The communication device 213 is capable of communicating in a manner corresponding to the wireless method of the aircraft 101. For example, it corresponds to LTE, 5G of a mobile network, WiFi of a private wireless network, etc., and communicates with the aircraft 101 through the base station A104. Here, as the corresponding wireless method, various communication methods can be adopted as in the case of the aircraft 101. Also, the base station A104 is a base station corresponding to the communication device 213. In this figure, one base station is connected, but a plurality of base stations may be connected.

[0041] The wireless information DB 214 is a database that stores the wireless information acquired by the aircraft 101 and the wireless information acquired by the communication device 213 of the control system 103. Since the wireless information is managed for each area size as described in the radio map management table 400 (see FIG. 4), an area is calculated from the position and altitude of the wireless information measured by the aircraft 101, and the wireless information is stored in the table of the corresponding area and stored. In this embodiment, various types of databases can be adopted.

[0042] FIG. 3 is a diagram showing an example of the radio map management screen 300 of the first embodiment.

[0043] The radio map management screen 300 includes a managed information display unit 301 and a radio map registration unit 306.

[0044] The managed information display unit 301 is a user interface including a base station display area 302 near the departure / arrival location, a base station selection area 303, a selected radio map display area 304, and a position / altitude selection area 305.

[0045] The base station display area 302 near the departure / arrival location displays the base stations existing near the departure / arrival port selected in the base station selection area 303. For example, in the base station display area 302 near the illustrated departure / arrival location, the departure / arrival port 102 and the base stations 307 to 309 are plotted on the map.

[0046] The selected radio map display area 304 displays the radio map at the position and altitude selected in the position / altitude selection area 305 for the base station selected in the base station selection area 303. After selecting a base station in the base station selection area 303 and operating the selection button 314 in the position / altitude selection area 305, the radio map is displayed by operating the display button 311. However, the display button 311 is not essential, and after selecting a base station, position, and height, the corresponding radio map may be automatically displayed, and various implementation forms can be adopted.

[0047] The radio map registration unit 306 is a user interface used when newly registering, adding, or updating a radio map. The position 314, altitude 315, area size 316 of the radio map to be registered, and the radio map file 317 representing radio information of the aircraft 101 are specified, and the radio map is registered by operating the registration button 318. The format of the radio map file may be various formats as long as it is a defined format such as CSV (Comma Separated Values) format or JSON (JavaScript Object Notation) format.

[0048] FIG. 4 is a diagram showing a configuration example of the radio map management table 400 managed in FIG. 3.

[0049] The radio map management table 400 manages the aircraft position 401, area size 402, base station ID 403, and radio map ID 404 as columns. The position (X, Y) of the aircraft position 401 is described by, for example, latitude and longitude information, and the altitude (Z) is described as the altitude from the ground surface. Also, the area size 402 specifies the mesh size of the radio map. The radio map is managed such that the position (X, Y) becomes the center of the radio map for each altitude (Z) of the aircraft position 401. Therefore, the radio information acquired at a certain position (X, Y) is the value up to the position separated by dividing the area size 402 by 2 from the position (X, Y).

[0050] The area size 402 recorded in the radio map management table 400 may be changed according to the height or may be the same regardless of the height. By managing the area size according to the altitude, it is possible to cope with the difference in communication distance characteristics for each altitude. For example, at a high altitude, there are fewer or no obstacles compared to a low altitude, so it may be treated as line-of-sight communication. That is, since the radio wave attenuation due to the communication distance is smaller than on the ground, it may be managed in a large area as radio information, reducing the storage area of the database and having the effect of being able to make a judgment according to the communication distance characteristics. On the other hand, as shown in FIG. 7, by managing with the same area size regardless of the altitude, the management of the radio map becomes easier.

[0051] The radio map ID 404 is identification information or a name that can uniquely identify a registered radio map.

[0052] Figure 5 is a diagram showing an example of the table configuration of a radio map, and shows an example of radio map 405.

[0053] The radio map 405 is composed of cell values 503 of cells divided into rows and columns, with cells 501 arranged vertically (same X-axis value) as columns and cells 502 arranged horizontally (same Y-axis value) as rows. In this embodiment, the levels of strong, medium, and weak are described as the value 503, but it may be the measurement result itself as wireless information, for example, a numerical value representing wireless quality such as radio field strength, packet error rate, delay, etc., and various values can be adopted.

[0054] Figure 6 is a diagram showing an example of a route from a certain altitude to land at a departure / arrival port and a radio map, and shows the selection of radio map values according to the flight route when landing from the position 602 of the aircraft 101 to the departure / arrival location 601 of the departure / arrival port 102.

[0055] In the example shown in Figure 6, as radio maps near the departure / arrival port 102, a radio map 405 at an altitude of 20 m, a radio map 406 at an altitude of 50 m, and a radio map 407 at an altitude of 100 m are managed. The area sizes of the radio maps are 10 m, 20 m, and 40 m respectively, as in the radio map management table 400 shown in Figure 4. At this time, according to the passing route, wireless information, which is the wireless quality at the time of landing, is calculated from one cell value of the 16-divided mesh in the radio map 405, one cell value of the 4-divided mesh in the radio map 406, and three cell values that are not divided in the radio map 407. In this way, it can be managed by changing the area size according to the altitude.

[0056] Figure 7 is a diagram showing an example of a route from a certain altitude to land at a departure / arrival port and a radio map, and shows the selection of radio map values according to the flight route when landing from the position 702 of the aircraft 101 to the departure / arrival location 701 of the departure / arrival port 102.

[0057] In the example shown in FIG. 7, as radio maps near the takeoff / landing port 102, a radio map 405 at an altitude of 20 m, a radio map 703 at an altitude of 50 m, and a radio map 704 at an altitude of 100 m are managed. The area size of all radio maps is 10 m. Also at this time, similar to FIG. 6, depending on the passing route, wireless information, which is the wireless quality at landing, is calculated from one cell value of the mesh divided into 16 parts in the radio map 405, one cell value of the mesh divided into 16 parts in the radio map 703, and one cell value of the mesh divided into 16 parts in the radio map 704. In this way, radio maps can be managed with a uniform area size regardless of altitude.

[0058] Next, with reference to FIGS. 8 to 10, based on the radio map, the flow of wireless communication control during takeoff / landing of the aircraft 101 and the operation flow for determining control information will be described.

[0059] FIG. 8 is a sequence diagram showing a control flow in which the air traffic control system 103 generates a radio map of a certain aircraft and the aircraft 101 communicates with the air traffic control system 103.

[0060] The wireless information registration unit 215 receives a new registration request for a radio map from the radio map registration unit 306 of the radio map management screen 300 (800), and checks with the wireless information acquisition unit 217 whether there is an existing radio map (801). When receiving the existing data check request, the wireless information acquisition unit 217 attempts to acquire from the wireless information DB 214 of the requested radio map. If the requested radio map can be acquired, there is an existing radio map; if the requested radio map cannot be acquired, there is no existing radio map. The wireless information acquisition unit 217 returns a confirmation result 803 for the existing data check request from the wireless information acquisition unit 217 to the wireless information registration unit 215. The wireless information registration unit 215 executes registration / updating / adding processing of the radio map according to the returned confirmation result 803 (804).

[0061] Next, for the aircraft 101 Communication Quality Measurement UnitWhen 207 receives the communication start request 805, a process for checking the communication quality between the base station 104 connected to the control system 103 and the aircraft 101 is executed. First, for the Communication Quality Measurement Unit of the aircraft 101 Communication Quality Measurement Unit 207 transmits the position, altitude, and acquired radio information of the aircraft 101 to the communication device 213 of the control system 103 (806). The communication device 213 transmits the received position, altitude, and radio information to the radio information acquisition unit 217 (807), and acquires the relevant radio wave map based on the position and altitude (810). Also, the newly received radio information from the aircraft 101 is transmitted to the radio information update unit 216 (808), and the radio information is updated (809).

[0062] The radio wave map generation unit 218 generates a radio wave map between the aircraft 101 and the departure / arrival port from the radio information acquired from the radio information acquisition unit 217 (811). The details of this radio wave map generation process 811 will be described later with reference to FIG. 10. The radio wave map generation unit 218 transmits the generated radio wave map to the communication device 213 (812). The communication device 213 transmits it to the aircraft 101 via wireless communication (813). Here, the communication device 213 determines the wireless reliability based on the generated radio wave map (815). In the reliability determination process 815, in order to improve the reliability of communication, the operation parameters of the retransmission / consecutive transmission control unit and the route control unit of the communication device 213 are determined, and communication with the aircraft 101 is performed using the determined communication method. Also in the retransmission / consecutive transmission control unit of the communication device 213 in the control system, the same judgment as that of the retransmission / consecutive transmission control unit 208 and the route control unit 209 is made to improve the reliability of communication.

[0063] Communication Quality Measurement Unit When 207 receives the radio wave map, similar to the communication device 213 in the control system 103, it determines the necessity of wireless control (814) and determines the number of consecutive transmissions / retransmissions and the transmission route. The details of the wireless control determination process 814 will be described later with reference to FIG. 9.

[0064] FIG. 9 is a flowchart of a radio control determination process 814 for determining the necessity of radio control with a flying object. Note that the flowchart of FIG. 9 shows control when all functions of Example 1 and Examples 2 and 3 described later are implemented, and steps corresponding to functions not implemented in each example are skipped. That is, Example 1 corresponds to steps S704 to S705, Example 2 corresponds to steps S706 to S707, and Example 3 corresponds to step S703.

[0065] In the radio control determination process 814, first, in step S901, Communication Quality Measurement Unit 207 receives a radio wave map from the radio wave map generation unit 218. In step S902, after receiving a plurality of radio wave maps, a base station candidate for the connection destination is specified. Since the radio wave map is managed for each base station, there may be one or more connection candidates. In step S902, for each of these candidates, the process from step S903 to step S910 is executed to specify a base station candidate for ensuring communication reliability suitable as the connection destination, and the process proceeds to step S903.

[0066] In step S903, it is determined whether the corresponding base station can be specified. If a specific base station can be specified, since continuous connection to the specified base station is possible without controlling the aircraft or adjusting the antenna directivity, the process proceeds to step S908. On the other hand, if a specific base station cannot be specified, the process proceeds to step S904.

[0067] In step S904, it is determined whether the antenna directivity of the flying object 101 can be adjusted. If it has a mechanism for adjusting the antenna directivity and a desired directivity can be obtained, the process proceeds to step S905, and if the antenna directivity cannot be adjusted, the process proceeds to step S906.

[0068] In step S905, the antenna directivity is adjusted in a direction to strengthen the directivity to the base station so as to continue communication with the base station. When the adjustment parameter is determined, the process proceeds to step S908.

[0069] In step S906, it is determined whether the directivity of the antenna can be adjusted by the aircraft control. When the aircraft is rotated horizontally with respect to the base station and the directivity can be adjusted, the process proceeds to step 907 (S907). If the directivity cannot be adjusted, the process proceeds to step S908.

[0070] In step S908, the number of retransmissions and consecutive transmissions is determined to improve the communication reliability with the base station. When the same radio packet is retransmitted the number of times determined in this step and the same application data is continuously transmitted (for example, the number of retransmissions is set to 2 and the number of consecutive transmissions is set to 3), compared with the settings without retransmission and without consecutive transmission, up to 9 times (number of consecutive transmissions × number of retransmissions + 1) of radio transmission opportunities can be obtained for the same application data. Therefore, if even one of the up to 9 radio packets reaches the destination base station, the wireless communication is successful and the reliability is improved. Thus, in this step, parameters for improving the reliability of wireless communication are determined. In this embodiment, functions other than the number of retransmissions and the number of consecutive transmissions that can improve communication reliability can be added to this step, and various reliability improvement functions can be adopted.

[0071] In step S909, it is checked whether there is an unconfirmed base station. If there is an unconfirmed base station, the process returns to step S902 to perform processing for the next base station candidate. On the other hand, when the processing for all base station candidates has been executed, the process proceeds to step S910.

[0072] In step S910, the optimal base station is selected from the base station candidates considering the radio map and communication reliability. For example, when based on the radio wave intensity from the base station, among the multiple radio maps managed for each altitude, the base station with the strongest radio wave intensity in the path from the current position of the aircraft to landing is selected. After selecting the base station, the process proceeds to step S911.

[0073] In step S911, it is checked whether there is an unconfigured communication device. Since the aircraft 101 has one or more wireless communication devices, if there is an unconfigured communication device, the process proceeds to step S902. If all have been configured, the process proceeds to step S912 to execute the process for the next communication device. On the other hand, if the process has been executed for all communication devices, the process ends.

[0074] FIG. 10 is a flowchart of the radio map generation process 811.

[0075] In the radio map generation process 811, first, in step S1101, it is determined whether a radio map corresponding to the position and altitude already exists. If the radio map exists, the process proceeds to step S1002. If the radio map does not exist, the radio map for the next position and altitude is searched for.

[0076] In step S1102, the corresponding radio map is acquired from the radio information DB 204, and after the acquisition, the process proceeds to step S1003.

[0077] In step S1003, it is determined whether the radio maps at all altitudes have been acquired in the section from the landing start position of the aircraft 101 to the departure / arrival port 102, or in the section from the departure / arrival port 102 to the flight altitude after takeoff. If the radio maps at all altitudes have been acquired, the process proceeds to step S1004. If there is an unacquired radio map, the process returns to step S1001.

[0078] In step S1004, in order to acquire the radio information for the positions on the flight path of the aircraft 101, the corresponding cells for each radio map are extracted from the position information and the cell size, and the values of the radio information of the extracted cells are stored. The values of the cells are extracted and stored from all the radio maps, and the process proceeds to step S1005.

[0079] In step S1005, map synthesis processing is performed using the values of the corresponding cells of all the radio wave maps stored in step S1004. The map synthesis processing may be, for example, adding all the cell values. In the map synthesis processing, various variations such as changing the weighting for each altitude and adding may be adopted. When the map synthesis processing is completed, this processing is terminated in step S1006.

[0080] As described above, according to the first embodiment, the interruption of wireless communication due to the handover process during takeoff and landing of the aircraft 101 can be suppressed, and furthermore, the reliability of wireless communication according to the route can be improved.

[0081] <Second Embodiment> In the first embodiment, in order to suppress the handover during takeoff and landing and to maintain the connection with a certain base station, a mechanical mechanism capable of adjusting the antenna directivity is required for the antenna 204-a2 or the antenna 204-b2, which increases the aircraft weight. In the second embodiment, an example is shown in which this problem is solved without requiring a mechanism for mechanical adjustment function and by changing the orientation of the aircraft itself. In the second embodiment, the configuration of the aircraft shown in FIG. 11 is different from that of the first embodiment and corresponds to steps S706 to S707 of the flowchart in FIG. 9. In the second embodiment, the configuration different from that of the first embodiment will be mainly described, and the same components and processes as those in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted.

[0082] FIG. 11 is a block diagram showing the configuration of the aircraft 1101 according to the second embodiment.

[0083] The aircraft 1101 includes a CPU 201, a flight control device 202, a positioning device 203, a wireless communication device A1104-a1, an antenna 204-a2, a wireless communication device B1104-b1, an antenna 204-b2, a wireless information storage device 205, and a communication control device 1106.

[0084] The CPU 201, the flight control device 202, the positioning device 203, the antenna 204-a2, the antenna 204-b2, and the wireless information storage device 205 are the same as those in the first embodiment.

[0085] The wireless communication device A1104-a1 and the wireless communication device B1104-b1 are wireless devices having a transceiver function corresponding to wireless communication methods such as LTE used as a mobile network, 5G, and WiFi used as a private wireless network. The wireless communication device A1104-a1 and the wireless communication device B1104-b1 may use the same wireless method or different wireless methods.

[0086] Similar to Example 1, the communication control device 1106 is a device that controls communication and is composed of a communication quality measurement unit 207, a retransmission / concatenation control unit 208, a path control unit 209, and a directivity adjustment unit 1110.

[0087] The directivity adjustment unit 1110 instructs the flight control device 202 of the aircraft 101 about the direction of the aircraft body that maintains good communication quality with the base station to which it wants to connect. That is, in Example 2, the direction of the antenna fixedly grounded to the aircraft body is controlled by the direction of the aircraft 101.

[0088] As described above, according to Example 2, without mounting an antenna directivity adjustment mechanism that causes an increase in the weight of the aircraft 101, it is possible to suppress the interruption of wireless communication due to the handover process during takeoff and landing of the aircraft 101, and further improve the reliability of wireless communication according to the path.

[0089] <Example 3> In Example 2, in order to suppress the handover during takeoff and landing and to maintain the connection with a certain base station, it is necessary to control the direction of the aircraft body of the aircraft 101, which causes restrictions on the operation of the aircraft body. In Example 3, an example of implementing this problem without using a mechanical control function is shown. In Example 3, the configuration of the aircraft shown in FIG. 12 is different from that of Examples 1 and 2 and corresponds to step S703 of the flowchart in FIG. 9. In Example 3, the configuration different from that of Examples 1 and 2 is mainly described, and the same components and processes as those in Examples 1 and 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0090] FIG. 12 is a block diagram showing the configuration of the aircraft 1201 of Example 3.

[0091] The aircraft 1201 includes a CPU 201, a flight control device 202, a positioning device 203, a wireless communication device 1204-a1, an antenna 1204-a2, a wireless information storage device 205, and a communication control device 1206.

[0092] The CPU 201, the flight control device 202, the positioning device 203, and the wireless information storage device 205 are the same as those in the first and second embodiments.

[0093] The wireless communication device 1204-a1 is a wireless device having a transmission and reception function according to a wireless communication method such as LTE used as a mobile network, 5G, or WiFi used as a private wireless network, and has a function of connecting to a designated base station. For example, it is possible to specify a connection destination by an SSID for identifying an access point of a wireless LAN, a base station ID of a mobile network, etc. When these can be specified, an unintentional switch to another base station can be suppressed, and the antenna directivity adjustment mechanism of the first embodiment and the device control process of the second embodiment are unnecessary.

[0094] Similar to the first embodiment, the communication control device 1206 includes a communication quality measurement unit 207, a retransmission / consecutive transmission control unit 208, and a path control unit 209, and the antenna directivity adjustment unit 210 of the first embodiment and the directivity adjustment unit 1110 of the second embodiment are unnecessary.

[0095] As described above, according to the third embodiment, without imposing restrictions on the flight of the aircraft 101, it is possible to suppress the interruption of wireless communication due to the handover process during takeoff and landing of the aircraft 101, and further improve the reliability of wireless communication according to the route.

[0096] In the embodiments described above, it is possible to grasp wireless information considering the flight altitude and flight route, and by managing the wireless information and controlling communication during takeoff and landing of the aircraft 101, it is possible to suppress the interruption of communication due to an unnecessary handover to a wireless station.

[0097] Note that the present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the scope of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Further, the configuration of another embodiment may be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations may be made.

[0098] Also, each of the above-described configurations, functions, processing units, processing means, etc. may be realized in hardware by designing a part or all of them, for example, by using an integrated circuit, or may be realized in software by a processor interpreting and executing a program for realizing each function.

[0099] Information such as programs, tables, files, etc. for realizing each function can be stored in a storage device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, a DVD.

[0100] Also, the control lines and information lines show those considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for implementation. In practice, it may be considered that almost all the configurations are interconnected.

Explanation of Reference Numerals

[0101] 101, 1101, 1201... Aircraft, 102... Departure and arrival port, 103... Control system, 104, 105... Base stations, 106... Departure and arrival location, 201... CPU, 202... Flight control device, 203... Positioning device, 204-a1, 204-b1... Wireless communication devices, 204-a2, 204-b2... Antennas, 205... Wireless information storage device, 206, 1106... Communication control devices, 207... Communication quality measurement unit, 208... Relay control unit, 209... Route control unit, 210... Antenna directivity adjustment unit, 211... Route planning device, 212... Wireless information management device, 213... Communication device, 215... Wireless information registration unit, 216... Wireless information update unit, 217... Wireless information acquisition unit, 218... Radio map generation unit, 300... Radio map management screen, 400... Radio map management table

Claims

1. A communication control system for controlling the communication of an aircraft during takeoff and landing, comprising: a control system having an arithmetic unit that executes predetermined processing and a storage device connected to the arithmetic unit; an aircraft that communicates with the control system via a base station; the control system stores a radio map representing the position, flight altitude, and radio wave quality for each base station of the aircraft; A communication control system characterized by selecting a base station with good radio quality on the takeoff / landing route at the takeoff / landing port by referring to radio maps at a plurality of altitudes.

2. The communication control system according to claim 1, wherein: the aircraft has: a function of adjusting the directivity of an antenna for communicating with the base station; Based on the radio maps at the plurality of altitudes, the directivity is controlled in the direction of the base station that is the communication partner to maintain the connection with the selected base station. A communication control system characterized by this.

3. The communication control system according to claim 1, wherein: the aircraft has: a function of controlling the orientation of the aircraft body to adjust the directivity of an antenna for communicating with the base station; Based on the radio maps at the plurality of altitudes, the directivity is controlled in the direction of the base station that is the communication partner to maintain the connection with the selected base station. A communication control system characterized by this.

4. The communication control system according to any one of claims 1 to 3, wherein: The area size for managing radio wave quality in the radio map varies depending on altitude. A communication control system characterized by this.

5. The communication control system according to any one of claims 1 to 3, wherein: The control system determines at least one of the number of retransmissions and the number of consecutive transmissions of data between the aircraft and the control system according to the radio quality determined based on the radio maps at the plurality of altitudes, and ensures the communication quality and communication reliability between the aircraft and the control system. A communication control system characterized by this.

6. The communication control system according to any one of claims 1 to 3, wherein: the control system: Determines whether a specific base station can be specified. If a specific base station can be specified, it controls to continuously connect to the specific base station; Determines whether the directivity of the antenna of the aircraft can be adjusted. If the directivity of the antenna can be adjusted, it controls the directivity of the antenna to face the specific base station. A communication control system is characterized in that it determines whether the directivity of an antenna can be adjusted by the aircraft control of the aircraft, and if the directivity of the antenna can be adjusted, the aircraft is controlled so that the directivity of the antenna faces a specific base station.

7. A communication control method for controlling the communication of an aircraft during takeoff and landing by a control system, wherein the control system has an arithmetic unit that executes predetermined processing and a storage device connected to the arithmetic unit, and communicates with the aircraft via a base station, the control system stores a radio wave map representing the position, flight altitude of the aircraft, and radio wave quality for each base station, the communication control method is as follows: the control system refers to the radio wave maps at the plurality of altitudes, selects a base station with good radio quality on the takeoff / landing path at the takeoff / landing port, and the aircraft maintains a connection with the selected base station during takeoff and landing at the takeoff / landing port.

8. The communication control method according to claim 7, wherein the aircraft has a function of adjusting the directivity of an antenna for communicating with the base station, the communication control method is as follows: the aircraft controls the directivity in the direction of the base station serving as the communication partner based on the radio wave maps at the plurality of altitudes, and maintains a connection with the selected base station.

9. The communication control method according to claim 7, wherein the aircraft has a function of controlling the orientation of the aircraft body to adjust the directivity of an antenna for communicating with the base station, the communication control method is as follows: the aircraft controls the directivity in the direction of the base station serving as the communication partner based on the radio wave maps at the plurality of altitudes, and maintains a connection with the selected base station.

10. The communication control method according to any one of claims 7 to 9, wherein the area size for managing radio wave quality in the radio wave map varies depending on altitude.

11. The communication control method according to any one of claims 7 to 9, wherein the control system determines at least one of the number of retransmissions and the number of consecutive transmissions of data between the aircraft and the control system according to the radio quality determined based on the radio wave maps at the plurality of altitudes, and ensures the communication quality and communication reliability between the aircraft and the control system.

12. The communication control method according to any one of claims 7 to 9, wherein the control system determines whether it is possible to specify a specific base station, and if it is possible to specify a specific base station, controls to continuously connect to the specific base station; determines whether it is possible to adjust the directivity of the antenna of the aircraft, and if the directivity of the antenna is adjustable, controls the directivity of the antenna to face a specific base station; determines whether it is possible to adjust the directivity of the antenna by controlling the aircraft body of the aircraft, and if the directivity of the antenna is adjustable, controls the aircraft body so that the directivity of the antenna faces a specific base station.

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