Distribution device, distribution system, and distribution method

Abstract

The purpose of the present disclosure is to provide a technology with which a large amount of data can be distributed at high speed from a distribution device to a group of mobile bodies having a limited amount of time with which to communicate with the distribution device. An orbiting satellite group (50) moves, according to a predetermined movement plan, through a route including a position where communication with a distribution device (41) is possible and a position where communication therewith is impossible. According to the movement plan, the timing at which each orbiting satellite (20) moves through the position where communication with the distribution device (41) is possible is different. The distribution device (41) comprises: an allocation unit (11) that divides overall data into a plurality of pieces of divided data and allocates each piece of divided data to a different orbiting satellite (20); and a transmission unit (12) that transmits the divided data piece in accordance with the allocation to the orbiting satellite (20) that is moving through the position where communication with the distribution device (41) is possible. The divided data pieces transmitted to the orbiting satellites (20) are shared by the orbiting satellite group (50), and in each of the orbiting satellites (20), the shared divided data pieces are integrated to create the overall data.

Description

Distribution Device, Distribution System, and Distribution Method

[0001] The present disclosure relates to a technique for distributing data from a distribution device to a group of moving objects.

[0002] A distribution system includes a distribution device and a group of moving objects composed of a plurality of moving objects. Here, the moving objects are, for example, artificial satellites, transport trucks, or construction machines. The distribution device distributes data such as firmware update programs to the group of moving objects in order to appropriately operate the group of moving objects.

[0003] Patent Document 1 discloses a method in which an assistance terminal device transmits data only to a specific construction machine that can communicate with itself among a plurality of construction machines. According to the method of Patent Document 1, a construction machine that cannot communicate with the assistance terminal device receives data from the assistance terminal device via another construction machine.

[0004] Japanese Patent Application Laid-Open No. 2019-179431

[0005] In the assistance system of Patent Document 1, by using communication between construction machines, data can be distributed to construction machines that cannot directly communicate with the assistance terminal device. However, the assistance system of Patent Document 1 assumes that an excavator that directly communicates with the assistance terminal device is waiting at the machine yard (paragraph 0111 of Patent Document 1), and direct communication with a moving object during movement to transmit data is not considered.

[0006] When the distribution device transmits data to a moving object that continues to move without staying in one place, there is a problem that a large amount of data cannot be transmitted at once because the communication available time with the moving object is limited. The present disclosure has been made to solve the above problems, and aims to provide a technology capable of quickly distributing a large amount of data from a distribution device to a group of moving objects whose communication available time with the distribution device is limited.

[0007] The distribution device of this disclosure is a distribution device that distributes data to a group of multiple mobile bodies. The group of mobile bodies moves along a path that includes locations where communication with the distribution device is possible and locations where communication is not possible, according to a predetermined movement plan. The timing at which each mobile body moves to a location where communication with the distribution device is possible differs according to the movement plan. The distribution device comprises an allocation unit that divides the overall data into multiple divided data and assigns each divided data to a different mobile body, and at least one transmission unit that transmits the divided data to each mobile body moving to a location where it is able to communicate with the distribution device, according to the assignment. The divided data transmitted to each mobile body is shared among the group of mobile bodies. At each mobile body, the shared divided data is integrated to create overall data.

[0008] The distribution device of this disclosure divides the overall data to be distributed to a group of mobile units into segmented data and transmits each segmented data to a different mobile unit, thereby enabling the transmission of segmented data to each mobile unit within a limited communication time. Furthermore, since the segmented data is shared among the mobile units and the shared segmented data is integrated to create the overall data, it becomes possible to distribute a large amount of overall data to each mobile unit. The purpose, features, embodiments, and advantages of this disclosure will become clearer from the following detailed description and accompanying drawings.

[0009] Figure 1 is a diagram showing an overview of the distribution system according to Embodiment 1. Figure 2 is a block diagram showing the configuration of the distribution system according to Embodiment 1. Figure 3 is a diagram showing the communication time between each orbiting satellite and the ground station. Figure 4 is a diagram showing an example of data division. Figure 5 is a diagram showing an overview of the distribution system according to Embodiment 2. Figure 6 is a block diagram showing the configuration of the distribution system according to Embodiment 2. Figure 7 is a diagram showing an overview of the distribution system according to Embodiment 3. Figure 8 is a block diagram showing the configuration of the distribution system according to Embodiment 3. Figure 9 is a diagram showing an overview of the distribution system according to Embodiment 4. Figure 10 is a block diagram showing the configuration of the distribution system according to Embodiment 3. Figure 11 is a diagram showing the hardware configuration of the distribution system. Figure 12 is a diagram showing the hardware configuration of the distribution system.

[0010] <A. Embodiment 1> <A-1. Configuration> Figure 1 is a diagram showing an overview of the distribution system 101 according to Embodiment 1. Figure 2 is a block diagram showing the functional configuration of the distribution system 101.

[0011] As shown in Figure 2, the distribution system 101 comprises a distribution device 41 and a constellation of orbiting satellites 50, which are a group of mobile objects to which the distribution device distributes data. The distribution device 41 is composed of a ground station 10 located on the ground. The constellation of orbiting satellites 50 is composed of a plurality of orbiting satellites 20 that orbit the Earth.

[0012] In the examples shown in Figures 1 and 2, the orbiting satellite constellation 50 consists of four orbiting satellites 20A, 20B, 20C, and 20D. However, in the following explanation, when referring to the constellation as a whole without specifying individual satellites, it will simply be referred to as orbiting satellite 20. The number of orbiting satellites 20 constituting the orbiting satellite constellation 50 does not need to be more than two.

[0013] The orbiting satellite 20 is an example of a mobile object. The mobile object may also be a drone, aircraft, train, bus, or taxi, in addition to an orbiting satellite.

[0014] Each orbiting satellite 20 is positioned in an orbit around the Earth. The orbits of each orbiting satellite 20 may be the same or different. The orbiting satellites 20 can send and receive data from each other through inter-satellite communication. However, it is not necessary for one orbiting satellite 20 to be able to communicate with all of the other orbiting satellites 20. It is sufficient that a network topology is formed connecting each orbiting satellite 20 so that the data held by one orbiting satellite 20 can be shared with all of the other orbiting satellites 20. For example, it is sufficient that each orbiting satellite 20 sequentially transfers data to other orbiting satellites 20 so that the data is eventually distributed to all orbiting satellites 20.

[0015] Each orbiting satellite 20 orbits the Earth according to a predetermined movement plan. Each orbiting satellite 20 cannot communicate with the ground station 10 at all times; it can only communicate with the ground station 10 while it is moving above the ground station 10. In other words, each orbiting satellite 20 moves along a path that includes positions where communication with the ground station 10 is possible and positions where communication is not possible, according to a predetermined movement plan. That is, each orbiting satellite 20 may sequentially traverse positions where communication with the ground station 10 is possible and positions where communication is not possible, or sequentially traverse positions where communication with the ground station 10 is not possible and positions where communication is not possible. Furthermore, each orbiting satellite 20 may repeatedly alternate between positions where communication with the ground station 10 is possible and positions where communication is not possible. Since the orbit of each orbiting satellite 20 is determined by kinematics, the time and duration when communication between the ground station 10 and each orbiting satellite 20 becomes possible can be predicted by calculating the orbit of each orbiting satellite 20. In other words, the orbital calculation result of the orbiting satellite 20 can be rephrased as the movement plan of the orbiting satellite 20.

[0016] Figure 3 shows an example of the communication time with the ground station 10 derived from the orbital calculation results of each orbiting satellite 20. In the example in Figure 3, orbiting satellite 20A can communicate with the ground station 10 from time T1 to time T2. That is, the communication time of orbiting satellite 20A with the ground station 10 is expressed as time T1-T2. Similarly, the communication time of orbiting satellite 20B with the ground station 10 is time T3-T4, the communication time of orbiting satellite 20C with the ground station 10 is time T5-T6, and the communication time of orbiting satellite 20D with the ground station 10 is time T7-T8. In addition, after orbiting satellite 20A moves above the ground station 10 at time T1-T2, it orbits the Earth once and becomes able to communicate with the ground station 10 again at time T9-T10. Thus, since the time during which each orbiting satellite 20 can communicate with the ground station 10 is limited, the amount of data that the ground station 10 can transmit to each orbiting satellite 20 in a single communication is limited.

[0017] As shown in Figure 2, the ground station 10 is configured to include an allocation unit 11 and a transmission unit 12. Here, we consider the distribution of firmware update programs to each orbiting satellite 20 by the ground station 10. That is, the update programs are the data that should be distributed from the ground station 10 to each orbiting satellite 20. The update programs are large in size and cannot be transmitted from the ground station 10 to each orbiting satellite 20 in a single communication.

[0018] Therefore, the allocation unit 11 divides the update program into multiple split programs and assigns the destination of each split program to each orbiting satellite 20. Hereinafter, assigning the destination of the split programs to the orbiting satellite 20 will be simply referred to as assigning the split programs to the orbiting satellite 20. If the update program is considered as the whole data, then the split programs correspond to the split data that has been divided from the whole data. In the example in Figure 4, the update program is divided into five split programs P1, P2, P3, P4, and P5, and split programs P1, P2, P3, and P4 are assigned to orbiting satellites 20A, 20B, 20C, and 20D, respectively. Also, split program P5 is assigned to orbiting satellite 20A. The transmission times of split programs P1, P2, P3, P4, and P5 are T1-T2, T3-T4, T5-T6, T7-T8, and T9-T10, respectively.

[0019] The amount of data for each divided program P1, P2, P3, P4, and P5 is kept within the range of data that the orbiting satellite 20 assigned to each divided program P1, P2, P3, P4, and P5 can receive from the ground station 10 in a single communication. Therefore, an orbiting satellite 20 that can receive a larger amount of data from the ground station 10 in a single communication than the other orbiting satellites 20 may be assigned a larger amount of data than the other orbiting satellites 20.

[0020] For example, in the example in Figure 3, the communication time (time T3-T4) of orbiting satellite 20B with the ground station 10 is assumed to be longer than the communication time of the other orbiting satellites 20A, 20C, and 20D with the ground station 10. Therefore, in the example in Figure 4, the amount of data in the divided program P2 allocated to orbiting satellite 20B is greater than the amount of data in the divided programs P1, P3, and P4 allocated to the other orbiting satellites 20A, 20C, and 20D. In this way, the update program may be divided based on the amount of data that each orbiting satellite 20 can communicate with the ground station 10 in a single communication.

[0021] The transmitting unit 12 transmits the divided programs P1, P2, P3, P4, and P5 to each orbiting satellite 20 according to the assignment made by the assignment unit 11. Specifically, the transmitting unit 12 transmits divided program P1 to orbiting satellite 20A at times T1-T2, divided program P2 to orbiting satellite 20B at times T3-T4, divided program P3 to orbiting satellite 20C at times T5-T6, divided program P4 to orbiting satellite 20D at times T7-T8, and divided program P5 to orbiting satellite 20A at times T9-T10.

[0022] Each split program may have additional information added to it, such as the number of splits, its position in the sequence of split programs, or the split program it should be integrated with. This additional information allows for the integration of split programs. Furthermore, each split program may have verification load information, such as CRC (Cyclic Redundancy Check), added to verify whether the transmission was successful. Additionally, the split programs may be encrypted for confidentiality.

[0023] As shown in Figure 2, the orbiting satellite 20 includes a communication unit 21 and an integration unit 22. The communication unit 21 communicates with the ground station 10 and with other orbiting satellites 20. When the communication unit 21 receives a segmented program from the ground station 10, it transmits that segmented program to the other orbiting satellites 20. The communication unit 21 also receives segmented programs that it has not received from the ground station 10 from other orbiting satellites 20. In the example in Figures 3 and 4, orbiting satellite 20A receives segmented programs P1 and P5 from the ground station 10, and the remaining programs P2-P4 are received from orbiting satellites 20B, 20C, and 20D. In this way, any segmented program received by any one orbiting satellite 20 from the ground station 10 is shared with all orbiting satellites 20 through inter-satellite communication.

[0024] The integration unit 22 integrates the segmented programs P1-P5 received from the ground station 10 and other orbiting satellites 20 to create an update program. This allows the orbiting satellites 20 to update their firmware using the update program.

[0025] The timing at which the division program is shared among the orbiting satellites 20 is not limited to after all division programs have been transmitted from the ground station 10. For example, after division program P1 has been transmitted from the ground station 10 to orbiting satellite 20A, but before division program P2 has been transmitted from the ground station 10 to orbiting satellite 20B, division program P1 may be shared among orbiting satellites 20A, 20B, 20C, and 20D via inter-satellite communication.

[0026] In this case, orbiting satellite 20A may transmit the division program P1 to orbiting satellites 20B, 20C, and 20D. Alternatively, orbiting satellite 20A may transmit the division program P1 to orbiting satellite 20B, orbiting satellite 20B may transmit the division program P1 to orbiting satellite 20C, and orbiting satellite 20C may transmit the division program P1 to orbiting satellite 20D. The shared timing of division programs P2-P5 is also arbitrary, similar to division program P1.

[0027] <A-2. Modification of Segmented Data Allocation> The above describes how the allocation unit 11 allocates segmented data to each orbiting satellite 20 based on the communication time available for each orbiting satellite 20 with the ground station 10. However, the allocation of segmented data may also be performed based on the reliability of communication between each orbiting satellite 20 and the ground station 10. If the orbits of each orbiting satellite 20 are not the same, the altitude of each orbiting satellite 20 as seen from the ground station 10 will be different. The lower the altitude of the orbiting satellite 20, the more unstable the communication with the ground station 10 becomes, and the more likely communication errors are to occur. Therefore, the allocation unit 11 may reduce the amount of segmented data allocated to orbiting satellites 20 with low communication reliability, or may not allocate any data at all. Here, communication reliability can be expressed, for example, by the bit error rate.

[0028] Furthermore, the allocation unit 11 may allocate divided data to each orbiting satellite 20 based on the communication bandwidth between each orbiting satellite 20 and the ground station 10. Specifically, the allocation unit 11 may allocate more divided data to orbiting satellites 20 with wider communication bandwidths, and allocate less divided data to orbiting satellites 20 with narrower communication bandwidths, or may not allocate any data at all.

[0029] <A-3. Modified example of transmitting duplicate division programs> In the above explanation, the allocation unit 11 transmitted one different division program to each orbiting satellite 20. However, if the communication performance between the ground station 10 and each orbiting satellite 20 is poor, that is, if the communication is unstable, there is a possibility that data transmission from the ground station 10 to each orbiting satellite 20 may fail. Therefore, if the communication performance in wireless communication between the ground station 10 and each orbiting satellite 20 is poor, for example, if the bit error rate is above a predetermined value, the allocation unit 11 may assign two or more division programs to each mobile entity, and a portion of these two or more division programs may overlap among multiple mobile entities.

[0030] For example, the ground station 10 may transmit divided programs P1 and P2 to orbiting satellite 20A, P2 and P3 to orbiting satellite 20B, P3 and P4 to orbiting satellite 20C, and P4 and P1 to orbiting satellite 20D. This ensures that even if the ground station 10 fails to communicate with orbiting satellite 20A, it can still transmit divided programs P1, P2, P3, and P4 to the orbiting satellite group 50 through the remaining orbiting satellites 20B, 20C, and 20D.

[0031] The above is an example of duplicate transmission of divided programs, but the same effect can be obtained by using error correction codes. Specifically, the transmission unit 12 applies error correction codes to divided programs P1-P4, so that divided program P1 becomes divided programs P1a and P1b, divided program P2 becomes divided programs P2a and P2b, divided program P3 becomes divided programs P3a and P3b, and divided program P4 becomes divided programs P4a and P4b. Then, the transmission unit 12 transmits divided programs P1a and P2b to orbiting satellite 20A, divided programs P2a and P3b to orbiting satellite 20B, divided programs P3a and P4b to orbiting satellite 20C, and divided programs P4a and P1b to orbiting satellite 20D. As a result, even if data communication becomes unstable at orbiting satellite 20A and data errors occur in divided programs P1a and P2b, the data errors can be corrected if divided programs 1b and 2a can be transmitted.

[0032] <A-4. Effects> The distribution device 41 according to Embodiment 1, the ground station 10, distributes data to a constellation 50 of orbiting satellites consisting of multiple artificial satellites. The constellation 50 moves along a path that includes positions where communication with the ground station 10 is possible and positions where communication is not possible, according to a predetermined movement plan. The timing at which each orbiting satellite 20 moves to a position where it can communicate with the ground station 10 differs according to the movement plan. The ground station 10 includes an allocation unit 11 that divides the overall data into multiple divided data and assigns each divided data to a different orbiting satellite 20, and a transmission unit 12 that transmits the divided data to each orbiting satellite 20 that is moving to a position where it can communicate with itself, according to the assignment.

[0033] Therefore, the ground station 10 can distribute a program with a larger data volume to the orbiting satellite constellation 50 than the program that can be transmitted to each orbiting satellite 20 in a single communication.

[0034] Furthermore, the segmented data transmitted to each orbiting satellite 20 is shared among the orbiting satellite constellation 50, and each orbiting satellite 20 integrates the shared segmented data to create the overall data. Therefore, the ground station 10 can distribute the program to all orbiting satellites 20 in fewer steps and in a shorter time than if it were to transmit the program to each orbiting satellite 20 individually. For example, the ground station 10 continuously transmits the segmented program to orbiting satellite 20A each time orbiting satellite 20A arrives, then the segmented program to orbiting satellite 20B each time orbiting satellite 20C arrives, and so on.

[0035] <B. Embodiment 2> <B-1. Configuration> Figure 5 is a diagram showing an overview of the distribution system 102 according to Embodiment 2. Figure 6 is a block diagram showing the functional configuration of the distribution system 102.

[0036] The distribution system 102 comprises a distribution device 42 and a constellation of orbiting satellites 50 from which data is distributed from the distribution device 42. The distribution device 42 is composed of multiple ground stations 10A and 10B. In the example shown in Figures 5 and 6, the distribution device 42 is composed of two ground stations 10A and 10B.

[0037] Ground station 10A includes an allocation unit 11 and a transmission unit 12. Ground station 10B includes a transmission unit 12. The allocation unit 11 may be provided in any of the multiple ground stations 10A and 10B. The operation of the allocation unit 11 and the transmission unit 12 is generally the same as in Embodiment 1. Ground station 10A transmits the allocation result of the allocation unit 11 to ground station 10B. Ground stations 10A and 10B are located in different geographical locations. That is, the transmission unit 12 of ground station 10A and the transmission unit 12 of ground station 10B are located in different geographical locations.

[0038] <B-2. Effects> In the distribution system 102 of Embodiment 2, the distribution device 42 is equipped with multiple transmission units 12 located at different geographical locations. With this configuration, for example, as shown in Figure 5, the divided program can be transmitted simultaneously or at short intervals from multiple ground stations 10, such as transmitting the divided program from ground station 10A to orbiting satellite 20A and simultaneously transmitting the divided program from ground station 10B to another orbiting satellite 20C. Therefore, the program can be distributed to all orbiting satellites 20 in a shorter time than in the configuration of Embodiment 1.

[0039] <C. Embodiment 3> <C-1. Configuration> Figure 7 is a diagram showing an overview of the distribution system 103 according to Embodiment 3. Figure 8 is a block diagram showing the functional configuration of the distribution system 103.

[0040] The distribution system 103 differs from the distribution system 102 according to Embodiment 2 in that it includes a geostationary satellite 30 and multiple ground stations 10A, 10B, and 10C constitute the distribution device 40. In the example shown in Figures 7 and 8, the distribution system 103 includes three ground stations 10A, 10B, and 10C. The geostationary satellite 30 is an example of a relay mobile unit that relays the transmission of a divided program from any of the ground stations 10A, 10B, or 10C to the orbiting satellite 20. Note that, like the distribution system 101 according to Embodiment 1, the distribution system 103 may include one ground station 10A and not include ground stations 10B and 10C.

[0041] The configurations of ground stations 10A and 10B are the same as in Embodiment 2. Ground station 10C has the same configuration as ground station 10B. The allocation unit 11 may be provided in any of the multiple ground stations 10A, 10B, and 10C. The allocation unit 11 provided in any of the ground stations 10A, 10B, and 10C transmits the allocation results of the division program to the other ground stations. The ground stations 10A, 10B, and 10C are geographically located at different locations. That is, the transmitting unit 12 of ground station 10A, the transmitting unit 12 of ground station 10B, and the transmitting unit 12 of ground station 10C are geographically located at different locations.

[0042] The orbiting satellite constellation 50 of the distribution system 103 includes orbiting satellites 20A, 20B, 20C, 20D, and 20E.

[0043] In the distribution system 103, the allocation unit 11 allocates the transmission destinations of some of the divided programs to the geostationary satellite 30 instead of the orbiting satellite 20.

[0044] The geostationary satellite 30 moves on a geostationary orbit and can always communicate with any one of the ground stations 10A, 10B, and 10C. In the example of FIG. 7, the geostationary satellite 30 stays above the ground station 10C and can always communicate with the ground station 10C.

[0045] The geostationary satellite 30 can communicate with at least one orbiting satellite 20 during one orbit of each orbiting satellite 20. In the example of FIG. 7, the geostationary satellite 30 can communicate with the orbiting satellite 20E. Thus, the geostationary satellite 30 is a moving body that does not belong to the orbiting satellite group 50, and moves along a path including a position where it can communicate with a distribution device, that is, any one of the ground stations 10A, 10B, and 10C, and a position where it can communicate with the orbiting satellite group 50 according to a predetermined movement plan.

[0046] Consider the transmission of a divided program from the ground station 10C to the orbiting satellite 20E. In order for the ground station 10C to directly transmit the divided program to the orbiting satellite 20E, it is necessary to wait for the orbiting satellite 20E to come above the ground station 10C. On the other hand, the ground station 10C can always transmit the divided program to the geostationary satellite 30, and currently, assume that the geostationary satellite 30 can communicate with the orbiting satellite 20E. In such a case, instead of waiting for the orbiting satellite 20E to become communicable, it is possible to transmit the divided program to the geostationary satellite 30 and transmit the data to the orbiting satellite 20E earlier via the geostationary satellite 30.

[0047] Therefore, the allocation unit 11 allocates some of the split programs to the geostationary satellite 30 instead of the orbiting satellite 20E. The ground station 10A transmits the allocation result of the allocation unit 11 to the other ground stations 10B and 10C. The transmission unit 12 of the ground station 10C transmits some of the split programs to the geostationary satellite 30 according to the allocation. When the geostationary satellite 30 receives the split program from the ground station 10C, it transmits the split program to the orbiting satellite 20E by inter-satellite communication. In the above description, the allocation unit 11 allocates some of the split programs to the geostationary satellite 30, but all of the split programs may be allocated to the geostationary satellite 30. That is, the allocation unit 11 may allocate at least some of the split programs to the geostationary satellite 30.

[0048] <C-2. Effect> In the distribution device 43 according to the third embodiment, the allocation unit 11 allocates at least some of the split data of the plurality of split data to the geostationary satellite 30, which is at least one relay mobile body, instead of the mobile body. The geostationary satellite 30 is an artificial satellite that does not belong to the orbiting satellite group 50 and moves along a path including a position where it can communicate with the distribution device 40 and a position where it can communicate with the orbiting satellite group 50 according to a predetermined movement plan. The allocation unit 11 allocates some of the split data to the geostationary satellite 30 instead of the orbiting satellite 20 based on the movement plan of the orbiting satellite group 50 and the movement plan of the geostationary satellite 30. With the above configuration, the distribution device 43 can deliver the split data to the orbiting satellite 20 earlier than directly transmitting the data to the orbiting satellite 20 by transmitting the split data via the geostationary satellite 30 according to the situation. Therefore, according to the distribution device 43, it is possible to transmit the split data to the orbiting satellite group 50 in a shorter time than the distribution device 41 of the first embodiment.

[0049] <D. Embodiment 4> <D-1. Configuration> FIG. 9 is a diagram showing an overview of a distribution system 104 according to the fourth embodiment. FIG. 10 is a block diagram showing the functional configuration of the distribution system 104.

[0050] The distribution system 104 comprises a distribution device 44 and a constellation of orbiting satellites 50 to which data is distributed from the distribution device 44. The distribution device 44 comprises a ground station 10 and geostationary satellites 30. In this embodiment, the ground station 10 comprises a transmission unit 12 and does not comprise an allocation unit 11.

[0051] The geostationary satellite 30 in this embodiment is configured to include an allocation unit 11 and a transmission unit 12. In other words, compared to the distribution device 41 of Embodiment 1, the distribution device 44 is equivalent to having the function of the allocation unit 11 moved from the ground station 10 to the geostationary satellite 30.

[0052] The transmitting unit 12 of the ground station 10 transmits the pre-split update program to the geostationary satellite 30. The allocation unit 11 of the geostationary satellite 30 splits the update program and allocates the split programs to each orbiting satellite 20 based on the movement plan of the geostationary satellite 30 and the orbiting satellite constellation 50. In Embodiment 1, the allocation of the split programs was based on the communication time available between the ground station 10 and each orbiting satellite 20. In contrast, in this embodiment, the allocation of the split programs is based on the communication time available between the geostationary satellite 30 and each orbiting satellite 20.

[0053] The transmission unit 12 of the geostationary satellite 30 transmits the division program to each orbiting satellite 20 according to the assignment of the assignment unit 11.

[0054] <D-2. Effects> The distribution device 44 according to Embodiment 4 includes a geostationary satellite 30, the ground station 10 transmits the entire data to the geostationary satellite 30, and the geostationary satellite 30 is equipped with an allocation unit 11 and a transmission unit 12. With this configuration, the distribution device 44 can distribute a program with a larger amount of data to the orbiting satellite group 50 than the program that can be transmitted from the geostationary satellite 30 to each orbiting satellite 20 in a single communication. In addition, the divided data transmitted to each orbiting satellite 20 is shared by the orbiting satellite group 50, and the shared divided data is integrated at each orbiting satellite 20 to create the entire data. As a result, the geostationary satellite 30 can distribute the program to all orbiting satellites 20 in fewer times and in a shorter time than if it were to transmit the program to each orbiting satellite 20 individually, by continuously transmitting the divided program to orbiting satellite 20A each time orbiting satellite 20A arrives, then continuously transmitting the divided program each time orbiting satellite 20B arrives, and so on.

[0055] <E. Hardware Configuration> The allocation unit 11 and transmission unit 12 in the distribution devices 41, 42, 43, and 44, and the communication unit 21 and integration unit 22 in the orbiting satellite constellation 50, are realized by the processing circuit 80 shown in Figure 11. That is, the processing circuit 80 comprises the allocation unit 11, the transmission unit 12, the communication unit 21, and the integration unit 22. Dedicated hardware may be applied to the processing circuit 80, or a processor that executes a program stored in memory may be applied. The processor may be, for example, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), etc.

[0056] When the processing circuit 80 is dedicated hardware, it may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0057] When the processing circuit 80 is a processor, the functions of the allocation unit 11, transmission unit 12, communication unit 21, and integration unit 22 (hereinafter referred to as the allocation unit 11, etc.) are realized by a combination of software, firmware, or software and firmware. The software, etc. is written as a program and stored in memory. As shown in Figure 12, the processor 81 applied to the processing circuit 80 realizes the functions of each unit by reading and executing the program stored in the memory 82. That is, the ground stations 10, 10A, 10B, 10C or geostationary satellites 30 that constitute the distribution devices 41, 42, 43, 44 are equipped with memory 82 for storing programs that, when executed by the processing circuit 80, result in the execution of the functions of the allocation unit 11 and the transmission unit 12, or the functions of the transmission unit 12. In addition, each orbiting satellite 20 is equipped with memory 82 for storing programs that, when executed by the processing circuit 80, result in the execution of the functions of the communication unit 21 and the integration unit 22. In other words, these programs cause the computer to execute the procedures or methods of the allocation unit 11, the transmission unit 12, the communication unit 21, and the integration unit 22. Here, the memory 82 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), an HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisc, a DVD (Digital Versatile Disk) and its drive device, or any storage medium that may be used in the future.

[0058] The above describes a configuration in which each function of the allocation unit 11, etc., is realized by either hardware or software. However, this is not the only configuration; a part of the allocation unit 11, etc., may be realized by dedicated hardware, and another part by software. For example, the allocation unit 11 can be realized by a processing circuit as dedicated hardware, while the other functions can be realized by a processing circuit 80 as a processor 81 that reads and executes a program stored in memory 82.

[0059] As described above, the processing circuit can realize each of the above functions through hardware, software, etc., or a combination thereof.

[0060] Although preferred embodiments have been described in detail above, the invention is not limited to the above embodiments, and various modifications and substitutions can be made to the above embodiments without departing from the scope of the claims.

[0061] 10 Ground station, 10A, 10B, 10C Ground station, 11 Allocation unit, 12 Transmitting unit, 20, 20A, 20B, 20C, 20D, 20E Orbiting satellite, 21 Communication unit, 22 Integration unit, 30 Geostationary satellite, 40, 41, 42, 43, 44 Distribution equipment, 50 Orbiting satellite constellation, 80 Processing circuit, 81 Processor, 82 Memory, 101, 102, 103, 104 Distribution system.

Claims

1. A distribution device for distributing data to a group of multiple mobile bodies, wherein the group of mobile bodies moves along a path that includes locations where communication with the distribution device is possible and locations where communication is not possible, according to a predetermined movement plan, the timing at which each mobile body moves to a location where communication with the distribution device is possible differs according to the movement plan, the distribution device comprises: an assignment unit that divides the overall data into a plurality of divided data and assigns each of the divided data to a different mobile body, and at least one transmission unit that transmits the divided data to each mobile body moving to a location where it is able to communicate with itself, according to the assignment, the divided data transmitted to each mobile body is shared among the group of mobile bodies, and the overall data is created by integrating the shared divided data in each mobile body.

2. The distribution device according to claim 1, wherein the allocation unit determines the amount of data of the divided data to be allocated to each of the moving bodies based on the length of time during which each of the moving bodies moves to a position in which it can communicate with at least one of the transmitting units in the movement plan.

3. The distribution device according to claim 1, wherein the allocation unit determines the amount of data of the divided data to be allocated to each mobile unit based on the communication bandwidth in the wireless communication between each mobile unit and the at least one transmitting unit.

4. The distribution device according to any one of claims 1 to 3, wherein the plurality of divided data consists of three or more divided data, and the allocation unit allocates two or more divided data, which are part of the three or more divided data, to each mobile unit when the bit error rate in wireless communication between the at least one transmitting unit and each of the mobile units is greater than or equal to a predetermined value, and a portion of the two or more divided data allocated to each mobile unit overlaps for each mobile unit.

5. The distribution device according to any one of claims 1 to 4, wherein the distribution device includes a ground station, and each of the mobile bodies is an orbiting satellite.

6. The distribution device according to claim 5, wherein the allocation unit calculates the time at which each of the orbiting satellites can communicate with the at least one transmitting unit by orbital calculation, and divides the total data into the plurality of divided data based on the calculated time and duration.

7. The distribution device according to claim 5 or 6, wherein the distribution device includes a geostationary satellite, the ground station transmits the total data to the geostationary satellite, and the geostationary satellite comprises the allocation unit and the at least one transmitting unit.

8. The distribution device according to any one of claims 1 to 4, wherein the allocation unit allocates at least a portion of the divided data of the plurality of divided data to at least one relay mobile body instead of the mobile body, the at least one relay mobile body is a mobile body not belonging to the mobile body group that moves along a path including a location where it can communicate with the distribution device and a location where it can communicate with the mobile body group, according to a predetermined movement plan, and the allocation unit allocates at least a portion of the divided data to the at least one relay mobile body instead of the mobile body based on the movement plan of the mobile body group and the movement plan of the at least one relay mobile body, 9. The distribution device according to claim 8, wherein the distribution device is a ground station, each of the mobile bodies is an orbiting satellite, and the at least one relay mobile body is at least one geostationary satellite.

10. The distribution device according to any one of claims 1 to 9, wherein the at least one transmitting unit is a plurality of transmitting units located at different geographical locations, and at least one of the plurality of transmitting units is equipped with the allocation unit.

11. A distribution system comprising: a distribution device according to any one of claims 1 to 10; and a group of mobile bodies consisting of a plurality of mobile bodies that receive the divided data from the distribution device.

12. A distribution method for a distribution device comprising an allocation unit and at least one transmission unit, which distributes data to a group of multiple mobile bodies, wherein the group of mobile bodies moves along a path including locations where communication with the distribution device is possible and locations where communication is not possible, according to a predetermined movement plan, the timing at which each mobile body moves to a location where communication with the distribution device is possible differs according to the movement plan, the allocation unit divides the overall data into a plurality of divided data, and assigns each of the divided data to a different mobile body, the at least one transmission unit transmits the divided data to each mobile body moving to a location where it is able to communicate with itself, the divided data transmitted to each mobile body are shared among the group of mobile bodies, and each mobile body integrates the shared divided data to create the overall data.

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