Patent Publication Number: US-2022238024-A1

Title: Flight route generation device and flight route generation method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the priority benefit of Japanese patent Application No. 2021-010637 filed on Jan. 26, 2021, the subject matter of which is hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a flight route generation device and a flight route generation method configured to generate a flight route (or a flight path) planned for a flight vehicle to fly along. 
     2. Description of Related Art 
     Recently, flight vehicles which are designed to fly along flight routes generated in advance have been widely spread in the world. As a method of setting a flight route, engineers have developed a technology of autonomously generating a flight route used to take aerial photos in a flight region set by a surveyor (see Patent Document 1, i.e., Japanese Patent Application Publication No. 2018-146546). Patent Document 1 discloses an information processing system designed to measure geographical positions (e.g., longitude, latitude, and altitude) of air-photo signals posted on grounds reflected in aerial photos. 
     The technology of Patent Document 1 allows a flight vehicle to fly over a single flight region during a one-time flight. When a user prefers a flight vehicle to fly over multiple flight regions in a one-time flight, it is possible for the user to conceive of setting a large flight area including multiple flight regions. However, the user may face a legal risk due to a flight vehicle inadvertently entering into a flight-prohibited area when any one of multiple flight regions included in a large flight area approaches is close to an airspace prohibiting any objects to fly therethrough such as third-party&#39;s premises. 
     The present invention is made in consideration of the aforementioned circumstances, and therefore the present invention aims to provide a flight route generation device and a flight route generation method configured to prevent a flight vehicle from entering into a flight-prohibited area and to generate a flight route allowing a flight vehicle to fly over multiple flight regions in a one-time flight. 
     SUMMARY OF THE INVENTION 
     In a first aspect of the present invention, a flight route generation device includes an acquisition unit configured to acquire the working-area information for designating a plurality of working areas intended for a plurality of operations to be performed by a flight vehicle during its flight and the interregional information for determining a plurality of interregional flight routes along which the flight vehicle is permitted to fly over a plurality of working areas, and a generator configured to generate a plurality of intraregional flight routes for the flight vehicle to fly through the plurality of working areas based on the working-area information and a plurality of interregional flight routes based on the interregional information. 
     In the above, the acquisition unit may acquire the interregional information representing an order of operations to be performed by the flight vehicle when flying through a plurality of working areas, wherein the generator may generate a plurality of interregional flight routes for the flight vehicle to move over a plurality of working areas according to the order of operations. In addition, the acquisition unit may acquire the interregional information representing at least one via-point which the flight vehicle passes through when flying over a plurality of working areas, wherein the generator may generate an interregional flight route passing through the via-point based on the interregional information. 
     When the flight vehicle moves between a first working area and a second working area among a plurality of working areas, the generator may generate an interregional flight route for the flight vehicle to move from the first working area to the second working area and a return route for the flight vehicle to return to the first working area from the second working area. 
     In addition, the acquisition unit may acquire the interregional information representing a flight-permitted area laid between a plurality of working areas, wherein the generator may generate an interregional flight route passing through the flight-permitted area based on the interregional information. Alternatively, the acquisition unit may acquire the interregional information representing a flight-prohibited area for prohibiting the flight vehicle from flying therethrough, which is laid between the plurality of working areas, wherein the generator may generate an interregional flight route not passing through the flight-prohibited area. 
     Moreover, when the flight vehicle moves between a first working area and a second working area among a plurality of working areas, the acquisition unit may acquire the first information representing a first operation-start point for starting a first operation and a first operation-end point for finishing the first operation in the first working area and the second information representing a second operation-start point for starting a second operation and a second operation-end point for finishing the second operation in the second working area, wherein the generator may generate an interregional flight route connected between the first operation-end point and the second operation-start npoint. 
     The acquisition unit may acquire the working-condition information representing a working condition for the flight vehicle to perform an operation for each working area among a plurality of working areas, wherein the generator may generate an intraregional flight route for each working area based on the working-condition information. 
     In a second aspect of the present invention, a flight route generation method implements: acquiring the working-area information for designating a plurality of working areas intended for a plurality of operations to be performed by a flight vehicle during its flight and the interregional information for determining a plurality of interregional flight routes along which the flight vehicle is permitted to fly over a plurality of working areas; generating a plurality of intraregional flight routes for the flight vehicle to fly through a plurality of working areas based on the working-area information; and generating a plurality of interregional flight routes based on the interregional information. 
     In a third aspect of the present invention, a non-transitory computer-readable storage media has a stored program causing a computer to implement a flight route generation method via acquiring the working-area information for designating a plurality of working areas intended for a plurality of operations to be performed by a flight vehicle during its flight and the interregional information for determining a plurality of interregional flight routes along which the flight vehicle is permitted to fly over a plurality of working areas; generating a plurality of intraregional flight routes for the flight vehicle to fly through a plurality of working areas based on the working-area information; and generating a plurality of interregional flight routes based on the interregional information. 
     According to the present invention, it is possible to achieve advantageous effects to generate a flight route used for a flight vehicle to fly above multiple flight regions in a one-time flight while preventing the flight vehicle from entering into a flight-prohibited area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing the overview of a flight route generation system according to the exemplary embodiment of the present invention. 
         FIG. 2  is a block diagram showing the configuration of a flight route input terminal. 
         FIG. 3  is a screenshot for a user to manually designate a working area displayed on the flight route input terminal. 
         FIG. 4  is a block diagram showing the configuration of a flight route generation device according to the exemplary embodiment of the present invention. 
         FIG. 5  is schematic diagram showing an exemplary method how to generate an intraregional flight route and an interregional flight route with the flight route generation device. 
         FIG. 6  is a schematic diagram showing an exemplary method how to generate a return route with the flight route generation device. 
         FIG. 7  is a block diagram showing the configuration of an operation terminal. 
         FIG. 8  is a block diagram showing the configuration of a flight vehicle. 
         FIG. 9  is a sequence diagram showing a procedure to generate a flight route according to the flight route generation system. 
         FIG. 10  is a schematic diagram showing an exemplary method how to generate an interregional flight route with a flight route generation device according to a variation of the exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
     The present invention will be described by way of examples with reference to the accompanying drawings, wherein parts identical or similar to those shown in various drawing will be denoted using the same reference signs; hence, duplication descriptions thereof will be omitted here. 
     1. Overview of Flight Route Generation System 
       FIG. 1  is a schematic diagram showing the overview of a flight route generation system S according to the exemplary embodiment of the present invention.  FIG. 1  briefly shows a configuration of the flight route generation system S. The flight route generation system S includes a flight route input terminal  100 , a flight route generation device  200 , an operation terminal  300 , and a flight vehicle  400 . 
     The flight route input terminal  100  is configured to communicate with the flight route generation device  200  by radio communication. For example, the flight route input terminal  100  is a tablet terminal. The flight route input terminal  100  accepts a user input to designate a plurality of working areas to be operated during a flight of the flight vehicle  400 . The working areas are provided for a user to perform activities such as taking aerial photos covering a certain range of grounds with the flight vehicle  400  and disseminating agricultural chemicals over farms. In addition, the flight route input terminal  100  accepts a user input to identify interregional routes allowing the flight vehicle  400  to move between multiple working areas. 
     The flight route generation device  200  is configured to generate flight routes for the flight vehicle  400  to fly along. The flight routes include an intraregional flight route for the flight vehicle  400  to fly over a working area as well as an interregional flight route extending over multiple working areas. 
     The operation terminal  300  is configured to communicate with the flight route generation device  200  and the flight vehicle  400  by radio communication. For example, the operation terminal  300  is a table terminal. For example, the flight vehicle  400  is a drone. The flight vehicle  400  is designed to fly along a flight route which is determined in advance. The flight vehicle  400  is designed to carry out predetermined activities during its flight. For example, the flight vehicle  400  may disseminate agricultural chemicals in the air over farms or take photos of buildings or agricultural produces on grounds. 
     Hereinafter, a flow of processes made by the flight route generation system S will be described below with reference to  FIG. 1 . The flight route input terminal  100  transmits to the flight route generation device  200  the working-area information representing a working area designated by a user operation and the interregional information identifying interregional routes (see ( 1 ) in  FIG. 1 ). 
     The flight route generation device  200  is configured to generate an intraregional flight route based on the working-area information acquired from the flight route input terminal  100 . In addition, the flight route generation device  200  is configured to generate an interregional flight route based on the interregional information acquired from the flight route input terminal  100 . The flight route generation device  200  is configured to transmit to the operation terminal  300  the flight-route information representing a flight route such as the intraregional flight route and the interregional flight route (see ( 2 ) in  FIG. 1 ). 
     The operation terminal  300  is configured to display the flight route, indicated by the flight-route information received from the flight route generation device  200 , on screen. The operation terminal  300  may input user operations for editing or defining the flight route. When a user makes an operation to define the flight route upon confirming the flight route on screen, the operation terminal  300  transmits to the flight vehicle  400  the flight-route information representing the flight route which is defined by the user or the edited flight route which is edited by the user (see ( 3 ) in  FIG. 1 ). The flight vehicle  400  may fly over the working area along the intraregional flight route indicated by the flight-route information. Alternatively, the flight vehicle  400  may move over multiple working areas along the interregional flight route indicated by the flight-route information. 
     As described above, the flight route generation device  200  is configured to generate an intraregional flight route along which the flight vehicle  400  may fly over each working area and an interregional flight route along which the flight vehicle  400  may move over multiple working areas. According to the flight route generation device  200 , it is possible to generate an intraregional flight route for each working area and an interregional flight route for multiple working areas along which the flight vehicle  400  may fly over multiple working areas in a one-time flight. At this time, the flight route generation device  200  can generate an interregional flight route based on the interregional information; hence, it is possible to prevent the flight vehicle  400  from entering into a flight-prohibited area such as a third-party&#39;s land when the flight vehicle  400  moves over multiple working areas. 
     2. Configuration of Flight Route Input Terminal  100   
       FIG. 2  is a block diagram showing the configuration of the flight route input terminal  100 . The flight route input terminal  100  includes a touch panel  11 , a communication unit  12 , a storage unit  13 , and a control unit  14 . The touch panel  11  is configured to detect a user touch or a user operation applied to a display surface for displaying images and/or characters. The communication unit  12  is a communication module allowing the flight route input terminal  100  to communicate with the flight route generation device  200  through networks. 
     The storage unit  13  is configured of storage media such as ROM (Read-Only Memory) and RAM (Random-Access Memory). The storage unit  13  is configured to store programs to be executed by the control unit  14 . For example, the control unit  14  is configured of a CPU (Central Processing Unit). The control unit  14  may achieve prescribed functions to realize an operation reception unit  141  and a communication control unit  142  by executing programs stored on the storage unit  13 . 
     The operation reception unit  141  is configured to receive a user operation via the touch panel  11 . That is, the operation reception unit  141  is configured to receive a user operation to designate multiple working areas involving activities to be performed by the flight vehicle  400  during its flight.  FIG. 3  shows an example of a screenshot for receiving a user operation to designate a working area.  FIG. 3  shows a map covering the neighborhood of a place involving a prescribed activity to be performed by the flight vehicle  400  during its flight. The screenshot of  FIG. 3  is used to designate working areas A 1  and A 2  with the operation reception unit  141 . Specifically, the operation reception unit  141  receives a user operation to designate vertexes (see black-dot symbols in  FIG. 3 ) of polygons illustrating boundaries of working areas A 1  and A 2 . 
     In  FIG. 3 , the operation reception unit  141  receive a user operation to designate a first operation-start point S 1  to start a first operation with the flight vehicle  400  and a first operation-end point G 1  to end the first operation in the working area A 1  designated by the user. In addition, the operation reception unit  141  receive a user operation to designate a second operation-start point S 2  to start a second operation with the flight vehicle  400  and a second operation-end point G 2  to end the second operation in the working area A 2  designated by the user. 
     The operation reception unit  141  receives a user operation to identify an interregional flight route when the flight vehicle  400  moves between the working area A 1  and the working area A 2 . For example, the operation reception unit  141  receives a user operation to identify a via-point (see a star-like symbol in  FIG. 3 ) which the flight vehicle  400  may go through on the interregional flight route. The operation reception unit  141  generates the interregional information representing a user operation to designate an interregional flight route. 
     In this connection, the interregional information is not necessarily limited to a via-point plotted on the interregional flight route. For example, the interregional information may identity a flight-prohibited area B laid between the working areas A 1  and A 2 , wherein the flight-prohibited area B prohibits the flight vehicle  400  to fly therethrough. Alternatively, the interregional information may identify a flight-permitted area which is laid between the working areas A 1  and A 2  and which permits the flight vehicle  400  to fly therethrough. The operation reception unit  141  generates and outputs the interregional information to the communication control unit  142 . 
     The operation reception unit  141  receives a user operation to designate working conditions of activities to be performed by the flight vehicle  400  during its flight. When the flight vehicle  400  is assigned a job to take aerial photos on the ground, for example, it is possible to mention various working conditions such as an imaging angle of view of an imaging device, an overlap ratio representing a ratio of longitudinal overlaps between imaging angles of view in the traveling direction of the flight vehicle  400 , and a side-lap ratio of lateral overlaps between imaging angles of view in the lateral/width direction of the flight vehicle  400 . When the flight vehicle  400  is assigned a job to disseminate agricultural chemicals, it is possible to mention types of agricultural chemicals and disseminating methods as working conditions. 
     The operation reception unit  141  receives and outputs the working-area information representing the received working areas, the interregional information, and the working-condition information to the communication control unit  142 . 
     The communication control unit  142  is configured to communicate with the flight route generation device  200  via the communication unit  12 . The communication control unit  142  is configured to transmit the working-area information, the interregional information, and the working-condition information to the flight route generation device  200 . The communication control unit  142  is configured to transmits the information representing an operation-start point and an operation-end point to the flight route generation device  200 . 
     3. Configuration of Flight Route Generation Device  200   
       FIG. 4  is a block diagram showing the configuration of the flight route generation device  200 . The flight route generation device  200  includes a communication unit  21 , a storage unit  22 , and a control unit  23 . The control unit  23  includes an acquisition unit  231 , a generator  232 , and a communication control unit  233 . 
     The communication unit  21  is an interface configured to communicate with the flight route input terminal  100  and the operation terminal  300  through networks. The storage unit  22  is configured of storage media such as ROM and RAM. The storage unit  22  is configured to store programs to be executed by the control unit  23 . For example, the control unit  23  is configured of a CPU. The control unit  23  may achieve functions to realize the acquisition unit  231 , the generator  232 , and the communication control unit  233  by executing programs stored on the storage unit  22 . 
     The acquisition unit  231  is configured to acquire various types of information from the flight route input terminal  100  via the communication unit  21 . Specifically, the acquisition unit  231  is configured to acquire the working-area information for designating multiple working areas used for the flight vehicle  400  to perform various activities during its flight. In addition, the acquisition unit  231  is configured to acquire the interregional information to identify interregional flight routes along which the flight vehicle  400  may move over multiple working areas. For example, the acquisition unit  231  may acquire the interregional information representing the position of at least one via-point laid between multiple working areas. Alternatively, the acquisition unit  231  may acquire from the flight route input terminal  100  the interregional information representing a flight-prohibited area for prohibiting the flight vehicle  400  to fly therethrough, which is laid between multiple working areas. Moreover, the acquisition unit  231  may acquire from the flight route input terminal  100  the interregional information representing a flight-permitted area laid between multiple working areas. 
     In addition, the acquisition unit  231  may acquire from an external device (not shown) the interregional information representing a flight-prohibited area which is laid between multiple working areas and which prohibits the flight vehicle  400  to fly therethrough or the interregional information representing a flight-permitted area which is laid between multiple working areas and which permits the flight vehicle  400  to fly therethrough. In this connection, the external device is configured to store a map database for storing the interregional information representing a flight-prohibited area or a flight-permitted area in association with the position information representing the position of the flight-permitted area or the like. The acquisition unit  231  transmits to the external device the position information representing a flight-start point at which the flight vehicle  400  starts flying in the air. The external device identifies the interregional information associated with the position information, representing a position plotted within a predetermined range from the flight-start point indicated by the received position information, in the map database. For example, the predetermined range can be defined as a range of distance which the flight vehicle  400  can reach in a one-time flight. The predetermined range can be set by a user in advance. The acquisition unit  231  may acquire the identified interregional information from the external device. 
     The acquisition unit  231  is configured to acquire the working-condition information representing working conditions of activities to be performed by the flight vehicle  400  during its flight. In addition, the acquisition unit  231  may acquire the information representing an operation-start point and an operation-end point for each working area. For example, the acquisition unit  231  may acquire the information representing the first operation-start point S 1  for starting a first operation and the first operation-end point G 1  for ending the first operation in the first working area A 1  within multiple working areas A 1 , A 2 . In addition, the acquisition unit  231  may acquire the information representing the second operation-start point S 2  for starting a second operation and the second operation-end point G 2  for ending the second operation in the second working area A 2  within multiple working areas A 1 , A 2 . The acquisition unit  231  may output to the generator  232  the working-area information, the interregional information, the working-condition information, and the information representing an operation-start point and an operation-end point. 
     4. Generation of Intraregional Route and Interregional Route 
     Based on the working-area information acquired by the acquisition unit  231 , the generator  232  is configured to generate a plurality of intraregional flight routes along which the flight vehicle  400  may fly over multiple working areas. Based on the interregional information acquired by the acquisition unit  231 , the generator  232  is configured to generate an interregional flight route along which the flight vehicle  400  may fly over multiple working areas. 
       FIG. 5  is a schematic diagram showing an exemplary method how to generate an intraregional flight route and an interregional flight route with the generator  232  of the control unit  23  included in the flight route generation device  200 .  FIG. 5  relates to an exemplary job for the flight vehicle  400  to take aerial photos in working areas while flying in the air. The generator  232  is configured to generate intraregional flight routes (see thin arrows drawn in  FIG. 5 ) along which the flight vehicle  400  is controlled to fly of the working areas A 1 , A 2  designated by the working-area information. Specifically, the generator  232  generates an intraregional flight route from the first operation-start point S 1  to the first operation-end point G 1  in the first working area A 1  according to the information acquired by the acquisition unit  231 . 
     At this time, the generator  232  is configured to generate an intraregional flight route based on the working-condition information acquired by the acquisition unit  231 . When the flight vehicle  400  is assigned a job of taking aerial photos in the working area A 1  on the ground with an imaging device, for example, the generator  232  generates an intraregional flight route such that a side-lap ratio between imaging angles of view may be adjusted to a prescribed value described in the working-condition information. Similarly, the generator  232  is configured to generate an intraregional flight route (see bold arrows drawn in  FIG. 5 ) along which the flight vehicle  400  may fly in a direction from the second operation-start point S 2  to the second operation-end point G 2  in the working area A 2  according to the information acquired by the acquisition unit  231 . 
     The generator  232  is configured to generate an interregional flight route along which the flight vehicle  400  moves in a direction from the working area A 1  to the working area A 2 . The generator  232  generates an interregional flight route connected between the first operation-end point G 1  of the working area A 1  and the second operation-start point S 2  of the working area A 2 . At this time, the generator  232  generates an interregional flight route passing through via-points (see star-like symbols in  FIG. 5 ) laid between the working areas A 1  and A 2 , which are indicated by the interregional information. 
     As shown in  FIG. 5 , the flight-prohibited area B is laid between the working area A 1  and the working area A 2 . In this connection, the generator  232  is able to generate an interregional flight route bypassing the flight-prohibited area B by generating the interregional flight route passing through via-points identified by the user. 
     When the acquisition unit  231  acquires the interregional information representing the flight-prohibited area B which is laid between the working areas A 1 , A 2  and which prohibits the flight vehicle  400  from flying therethrough, the generator  232  may generate an interregional flight route which instructs the flight vehicle  400  not to go through the flight-prohibited area B. When the acquisition unit  231  acquires the interregional information representing a flight-permitted area which permits the flight vehicle  400  to fly therethrough over the working areas A 1 , A 2 , the generator  232  may generate an interregional flight route which instructs the flight vehicle  400  to go through the flight-permitted area indicted by the interregional information. 
     Alternatively, the generator  232  may generate an interregional flight route based on the interregional information representing both the via-points and the flight-prohibited area (or the flight-permitted area). For example, the generator  232  may generate an interregional flight route which instructs the flight vehicle  400  to pass through the via-points but not to go through the flight-prohibited area. Similarly, the generator  232  may generate an interregional flight route based on the interregional information representing both the via-points and the flight-permitted area. For example, the generator  232  may generate an interregional flight route which instructs the flight vehicle  400  to pass through the via-points and to go through the flight-permitted area. 
     5. Generation of Return Route 
     In addition to generating an interregional flight route for the flight vehicle  400  to move from the first working area A 1  to the second working area A 2 , the generator  232  may generate a return route for the flight vehicle  400  to return to the first working area A 1  from the second working area A 2  after completing a second operation in the second working area A 2 .  FIG. 6  shows an example of a return route generated by the generator  232 . That is, the generator  232  may generate a return route for the flight vehicle  400  to return to the first operation-start point S 1  of the first working area A 1  from the second operation-end point G 2  of the second working area A 2 . According to the return route, the flight vehicle  400  is controlled to return from the second operation-end point G 2  to the second operation-start point S 2  of the second working area A 2  via the shortest route. 
     According to the return route, the flight vehicle  400  subsequently moves in a reverse flight route reverse to the interregional flight route along which the flight vehicle  400  moved from the first working area A 1  to the second working area A 2 , whereby the flight vehicle  400  will return to the first operation-end point G 1  of the first working area A 1  from the second operation-start point S 2  of the second working area A 2 . According to the return route, the flight vehicle  400  finally returns to the first operation-start point S 1  from the first operation-end point G 1  in the first working area A 1  via the shortest route. When the first operation-start point S 1  is not a flight-start position, the generator  232  may generate a further return route for the flight vehicle  400  to return to its flight-start position from the first operation-start point S 1 . 
     In the above, the generator  232  is not necessarily configured to generate a return route for the flight vehicle  400  to move in a revere flight route reverse to the interregional flight route from the first operation-end point G 1  to the second operation-start point S 2 . For example, the generator  232  may generate a return route which is different from the interregional flight route but which passes through the same via-point (see a star-like symbol in  FIG. 6 ) included in the interregional flight route from the first operation-end point G 1  to the second operation-start point S 2 . Alternatively, the generator  232  may generate a return route along which the flight vehicle  400  moves from the second operation-start point S 2  to the first operation-end point G 1  but which passes through a different via-point than the via-point included in the interregional flight route from the first operation-end point G 1  to the second operation-start point S 2 . 
     The communication control unit  233  is configured to communicate with the operation terminal  300  via the communication unit  21 . The communication control unit  233  is configured to transmit to the operation terminal  300  the flight-route information including the intraregional flight route and the interregional flight route. In addition, the communication control unit  33  is configured to transmit to the operation terminal  300  the operation-condition information acquired by the acquisition unit  231 . Moreover, the communication control unit  233  is configured to transmit to the operation terminal  300  the information representing an operation-start point and an operation-end point for each working area. 
     6. Configuration of Operation Terminal  300   
       FIG. 7  shows the configuration of the operation terminal  300 . The operation terminal  300  includes a communication unit  31 , a display unit  32 , a touch panel  33 , a storage unit  34 , and a control unit  35 . The control unit  35  includes a communication control unit  351 , a display control unit  352 , an operation reception unit  353 , and a flight management unit  354 . 
     The communication unit  31  is an interface configured to communicate with the flight route generation device  200  and the flight vehicle  400  through networks. In the exemplary embodiment, for example, the communication unit  31  is configured to communicate with the flight vehicle  400  via a repeater apparatus (or a relay station). The display unit  32  is configured to display images and characters on screen. The touch panel  33  is configured to detect a user operation applied to the screen of the display unit  32 . 
     The storage unit  34  is configured of storage media including ROM, RAM, or the like. The storage unit  34  is configured to store programs to be executed by the control unit  35 . For example, the control unit  35  is configured of a CPU. The control unit  35  can achieve functions to realize the communication control unit  351 , the display control unit  352 , the operation reception unit  353 , and the flight management unit  354  by executing programs stored on the storage unit  34 . 
     The communication control unit  352  is configured to communicate with the flight route generation device  200  via the communication unit  31 . The communication control unit  351  is configured to receive the working-condition information and the flight-route information generated by the flight route generation device  200 . The communication control unit  351  is configured to receive the information representing an operation-start point and an operation-end point for each working area. The flight control unit  351  may receive the output the flight route information to the display control unit  352 , the operation reception unit  353 , and the flight management unit  354 . In addition, the communication control unit  351  may receive and output the operation-condition information to the flight management unit  354 . 
     The display control unit  352  is configured to display various types of information on the screen of the display unit  32 . For example, the display control unit  352  may display a flight route, represented by the flight-route information received by the communication control unit  351 , on the screen of the display unit  32 . The display control unit  352  may display a button (e.g., an OK button), which can be operated by a user to define a flight route, and another button allowing the user to edit the flight route. 
     The operation reception unit  353  is configured to receive a user operation via the touch panel  33 . The operation reception unit  353  may receive a user operation to define the flight route indicated by the flight-route information or a user operation to edit the flight route. In addition, the operation reception unit  353  may receive a user operation to instruct completion of editing the flight route. 
     The operation reception unit  353  may receive a user operation to instruct a flight-start time of the flight vehicle  400 . Subsequently, the operation reception unit  353  may output to the flight management unit  354  the time information representing the flight-start time and the flight-route information representing the already-defined flight route (or the edited flight route when edited by a user operation). 
     The flight management unit  354  is configured to communicate with the flight vehicle  400  via the communication unit  31 . The flight management unit  354  is configured to transmit the flight-route information to the flight vehicle  400 . The flight management unit  354  is configured to transmit to the flight vehicle  400  the working-condition information received by the communication control unit  351 . In addition, the flight management unit  354  is configured to transmit the time information to the flight vehicle  400 . Moreover, the flight management unit  354  is configured to transmit to the flight vehicle  400  the information representing an operation-start point and an operation-end point for each working area. 
     7. Configuration of Flight Vehicle  400   
       FIG. 8  is a block diagram showing the configuration of the flight vehicle  400 . The flight vehicle  400  includes a communication unit  41 , a flight mechanism  42 , an imaging device  43 , a storage unit  44 , and a control unit  45 . The control unit  45  includes a communication control unit  451 , a flight control unit  452 , and an operation processing unit  453 . 
     The communication unit  41  is a communication module configured to wirelessly communicate with the operation terminal  300  via a repeater apparatus. For example, the flight mechanism  42  includes motors configured to rotate multiple rotors. The imaging device  43  is configured to take photos of images beneath the flight vehicle  400  during its flight. 
     The storage unit  44  is configured of storage media including ROM, RAM, or the like. The storage unit  44  is configured to store programs to be executed by the control unit  45 . For example, the control unit  45  is configured of a CPU. The control unit  45  can achieve functions to realize the communication control unit  451 , the flight control unit  452 , and the operation processing unit  453  by executing programs stored on the storage unit  44 . 
     The communication control unit  451  is configured to communicate with the operation terminal  300  via the communication unit  41 . The communication control unit  451  is configured to receive the flight-route information and the working-condition information. The communication control unit  451  is configured to receive the time information representing a flight-start time. The communication control unit  451  is configured to receive the information representing an operation-start point and an operation-end point for each working area. The communication control unit  451  may receive and output the flight-route information and the time information to the flight control unit  42 . In addition, the communication control unit  451  may receive and output the flight-route information and the working-condition information to the operation processing unit  453 . Moreover, the communication control unit  451  may transmit the information representing a flight condition such as a battery level of the flight vehicle  400  to the operation terminal  300 , which in turn displays the battery level on the screen of the display unit  32 . 
     The flight control unit  452  is configured to control the flight vehicle  400  to fly in the air by generating a control signal to drive the flight mechanism  42 . The flight control unit  452  controls the flight vehicle  400  to start flying at a flight-start time indicated by the time information. The flight control unit  452  controls the flight vehicle  400  to fly along flight routes such as an intraregional flight route, an interregional flight route, and a return route included in the flight-route information received by the communication control unit  451 . Specifically, the flight control unit  452  may control the flight vehicle  400  to fly along an intraregional flight route in each working area. In addition, the flight control unit  452  may control the flight vehicle  400  to fly along an interregional flight route over multiple working areas. Moreover, the flight control unit  452  may control the flight vehicle  400  to fly along the return route from the operation-end point of the working area, in which the operation processing unit  453  has carried out a last operation, to the flight-start position. 
     The operation processing unit  453  is configured to carry out a predetermined operation during the flight of the flight vehicle  400  under the control of the flight control unit  452 . For example, the operation processing unit  453  may control the imaging device  43  to take photos of images beneath the flight vehicle  400  during its flight. The operation processing unit  453  is configured to identify the current position of the flight vehicle  400  using a GPS (Global Positioning System) sensor (not shown), wherein the operation processing unit  543  starts a prescribed operation when the flight vehicle  400  reaches the operation-start point and then finishes the prescribed operation when the flight vehicle  400  reaches the operation-end point. For example, the operation processing unit  453  may control the imaging device  43  to take photos of images beneath the flight vehicle  400  in an imaging cycle in which the overlap ratio of imaging angles of view becomes equal to a prescribed value indicated by the working-condition information. 
     8. Procedure of Generating Flight Route 
       FIG. 9  is a sequence diagram showing a procedure to generate a flight route according to the flight route generation system S (see a series of steps S 11  through S 15 ). For example, the procedure is started upon applying power to the flight route input terminal  100 . The operation reception unit  141  of the flight route input terminal  100  may receive a user operation to designate multiple working areas subjected to a prescribed operation to be carried out by the flight vehicle  400  during its flight. In addition, the operation reception unit  141  may receive a user operation to designate working conditions for a prescribed operation to be carried out by the flight vehicle  400  during its flight. Moreover, the operation reception unit  141  may receive a user operation to determine an interregional flight route for the flight vehicle  400  to move over multiple working areas. 
     The communication control unit  142  of the flight route input terminal  100  transmits to the flight route generation device  200  the working-area information representing working areas received by the operation reception unit  141 , the interregional information representing a user operation to identify an interregional route, and the working-condition information representing working conditions to be implemented by the flight vehicle  400  during its flight. The generator  232  of the flight route generation device  200  may generate flight routes such as an intraregional flight route and an interregional flight route (S 11 ). 
     The communication control unit  233  of the flight route generation device  200  transmits to the operation terminal  300  the flight-route information representing flight routes generated by the generator  232 . In addition, the communication control unit  233  transmits to the operation terminal  300  the working-condition information acquired by the acquisition unit  231 . 
     The operation reception unit  353  of the operation terminal  300  receives a user operation to define or edit the flight routes included in the flight-route information. In addition, the operation reception unit  353  receives a user operation to designate a flight-start time of the flight vehicle  400 . The flight management unit  354  determines whether or not the operation reception unit  353  has received a user operation to define the flight routes (S 12 ). Upon determining that the operation reception unit  353  has received a user operation to define the flight routes (i.e., YES of S 12 ), the flight management unit  354  transmits to a repeater apparatus the flight-route information representing the already-defined flight routes, the working-condition information representing working conditions, and the time information representing a flight-start time of the flight vehicle  400 . The repeater apparatus repeats and transmits the flight-route information, the working-condition information, and the time information to the flight vehicle  400 . 
     The flight control unit  452  of the flight vehicle  400  controls the flight vehicle  400  to starts flying at the flight-start time indicated by the time information received by the communication control unit  451  (S 13 ). In this connection, the flight control unit  452  does not necessarily start the flight of the flight vehicle  400  immediately after the flight-start time in consideration of safety standards. For example, the flight control unit  452  may be set to a standby state ready to start flight at the flight-start time, and then the flight control unit  452  may start flight on the condition that the communication control unit  451  receives a flight-start command, instructing the flight vehicle  400  to start flying in the air, from the operation terminal  300  in the standby state. The operation processing unit  453  starts to perform a prescribed operation indicated by the working-condition information with the flight vehicle  400  when the flight vehicle  400  reaches an operation-start point in a working area according to the working-condition information (S 14 ). The operation processing unit  453  finishes the prescribed operation when the flight vehicle  400  reaches an operation-end point in the working area (S 15 ). Thus, the flight route generation system S exits the processing described above. Upon determining that the operation reception unit  353  has not received a user operation to define flight routes in step S 12  (i.e., NO of S 12 ), the flight management unit  354  may repeat the step S 12 . 
     9. Variation 
     The exemplary embodiment refers to a scenario in which the acquisition unit  231  of the flight route generation device  200  is configured to acquire the interregional information representing a via-point which the flight vehicle  400  should pass through when moving over multiple working areas; however, the present invention is not necessarily limited to this scenario. The acquisition unit  232  may acquire the interregional information representing an order of operations to be performed by the flight vehicle  400  over multiple working areas. For example, the operation reception unit  141  of the flight route input terminal  100  may generate the interregional information upon receiving a user operation to designate an order of operations to be performed by the flight vehicle  400 . 
     The generator  232  of the flight route generation device  200  may generate multiple interregional routes for the flight vehicle  400  to move over multiple working areas to achieve an order of operations indicated by the interregional information acquired by the acquisition unit  231 .  FIG. 10  is a schematic diagram showing an exemplary method of how to generate interregional routes with the generator  232  of the flight route generation device  200  according to a variation of the exemplary embodiment.  FIG. 10  shows a map of the neighborhood including multiple working areas A 1  through A 4  over which the flight vehicle  400  should achieve an order of operations.  FIG. 10  shows multiple working areas A 1  through A 4  and the flight-prohibited area B prohibiting the flight of the flight vehicle  400 . 
       FIG. 10  shows the operation-start point S 1  and the operation-end point G 1  of the working area A 1 , the operation-start point S 2  and the operation-end point G 2  of the working area A 2  as well as an operation-start point S 3  and an operation-end point G 3  of a working area A 3 , an operation-start point S 4  and an operation-end point G 4  of a working area A 4 . In  FIG. 10 , thin-solid-line arrows show intraregional flight routes in the working areas A 1  through A 4 , while bold-line arrows show interregional flight routes over the working areas A 1  through A 4 . 
       FIG. 10  shows an exemplary scenario in which the acquisition unit  231  of the flight route generation device  200  has acquired the interregional information which instructs the flight vehicle  400  to carry out a series of operation in an order of the working areas A 1 , A 2 , A 3 , and A 4 . At this time, the generator  232  of the flight route generation device  200  generates an interregional flight route from the working area A 1  to the working area A 2 , an interregional flight route from the working area A 2  to the working area A 3 , and an interregional flight route from the working area A 3  to the working area A 4  as shown by bold-line arrows in  FIG. 10 . 
     If the generator  232  generated an interregional flight route directly from the working area A 1  to the working area A 4  (see a bold-dotted-line arrow in  FIG. 10 ), the flight route generation device  200  suffers from a problem in that the generator  232  might have generated an unpermitted interregional flight route passing through the flight-prohibited area B. In this variation, the flight route generation device  200  is designed to generate a series of interregional flight routes for the flight vehicle  400  to fly over multiple working areas A 1  through A 4  in an order designated by a user, wherein the generator  232  is configured to generate a series of interregional flight routes bypassing the flight-prohibited area B. 
     For example, programs realizing a flight route generation method of the exemplary embodiment will be provided as a WEB application to be executed by the flight route generation device  200 . Flight routes generated by this application will be displayed on the screen of the operation terminal  300  via a WEB browser. In this connection, programs realizing a flight route generation method of the exemplary embodiment can be provided as applications to be executed by the flight route input terminal  100  or the operation terminal  300 . 
     As described above, the foregoing embodiment is designed to provide the flight route input terminal  100  and the operation terminal  300  as independent apparatuses; however, this is not a restriction in the present invention. That is, it is possible to provide a single apparatus unifying the flight route input terminal  100  and the operation terminal  300 . Alternatively, it is possible to provide a single apparatus unifying at least two or more of the flight route input terminal  100 , the flight route generation device  200 , and the operation terminal  300 . In addition, the present embodiment is not necessarily limited to the foregoing embodiment in which the flight route generation device  200  and a repeater apparatus are provided as independent apparatuses. For example, it is possible to provide a single apparatus unifying the flight route generation device  200  and the repeater apparatus. 
     10. Advantageous Effects of Flight Paten Generation Device  200   
     In the flight route generation device  200 , the generator  232  is configured to generate intraregional flight routes for the flight vehicle  400  to fly in multiple working areas and interregional flight routes for the flight vehicle  100  to fly over multiple working areas. That is, the generator  232  is able to generate a plurality of intraregional flight routes and a plurality of interregional flight routes for the flight vehicle  400  to fly over multiple working areas in a one-time flight. At this time, the generator  232  is configured to generate interregional flight routes based on the interregional information acquired by the acquisition unit  231 , and therefore it is possible to prevent the flight vehicle  400  from inadvertently entering into a flight-prohibited area such as a third-party&#39;s land when the flight vehicle  400  is flying over multiple working areas. In this connection, the present invention may contribute to Sustainable Development Goals (SDGs) initiated by the United Nations (UN), in particular, Goal 9 “Industry, Innovation and Infrastructure”. 
     Heretofore, the present invention has been described by way of the foregoing embodiments (e.g., the exemplary embodiment and its variation), wherein the technical scope of the invention is not necessarily limited to the foregoing embodiments; hence, it is possible to create and introduce any other variations and modifications within the subject matter of the invention. For example, it is possible to physically or functionally disperse or integrate part or entirety of the foregoing devices in arbitrary units of components. In addition, the present invention may embrace any new examples produced by arbitrarily combining the foregoing embodiments. It can be said that new examples produced by combinations of the foregoing embodiments will offer the same advantageous effects as the exemplary embodiment. 
     While the preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.