Communication control device, communication control method, communication control program, communication control system, relay satellite, and satellite system

Abstract

To transmit data of more satellites from a relay satellite using optical communication to other devices while satisfying a limit value of the data rate between the relay satellite and other devices, when the relay satellite relays communications between a plurality of satellites and other devices using optical communication. [Solution] When the relay satellite 2 relays communications between multiple user satellites 3A, 3B, 3C and other devices, the communication control device 16 controls optical communications between the relay satellite 2 and multiple user satellites 3A, 3B, 3C so that the sum of the data rates representing the amount of communication per unit time between the relay satellite 2 and the multiple user satellites 3A, 3B, 3C is less than or equal to the limit value of the data rate between the relay satellite 2 and other devices.

Description

[Technical Field]

[0001] The present disclosure relates to a communication control device, a communication control method, a communication control program, a communication control system, a relay satellite, and a satellite system. [Background technology]

[0002] Conventionally, an optical downlink system between a remote terminal having n optical communication terminals (OT1-OTn) and a terrestrial terminal including n clusters of optical terrestrial base stations (OGS1-OGSn) connected by n optical downlink channels (DL1-DLn) or n optical uplink channels (UC1-UCn) is known (e.g., Patent Document 1). This optical downlink system is configured to synchronize the n optical terrestrial base stations (OGS1-OGSn) so that the n optical downlink channels are spatially separated from each other by the optical terrestrial base stations (OGS1-OGSn) located at specific distances from each other, and the optical uplink channels (UC1-UCn) are temporally separated to ensure temporal separation, thereby avoiding overlap between the optical uplink channels (UC1-UCn) (e.g., [claims 1 and 8] of Patent Document 1).

[0003] Also known is a space-propagation optical communication system including a constellation of several satellites (for example, Patent Document 2). This space-propagation optical communication system includes a satellite constellation having a plurality of uplink / downlink optical telescopes for optical communication with a plurality of ground sites, and when each of the satellites passes over a predetermined ground site, one or more of the uplink / downlink telescopes of the predetermined satellite are configured to track at least two of the terrestrial optical telescopes at the predetermined ground sites and transmit data to the terrestrial optical telescope with the clearest line of sight to the predetermined satellite (for example, [Claim 1] of Patent Document 2).

[0004] Also known is a mobile satellite communication system that can flexibly respond to temporary surges in communication demand, etc. (see, for example, Patent Document 3). This mobile satellite communication system is provided with a flying relay station that flies several to several tens of kilometers above the ground between a low-earth orbit communication satellite and its communication area, and relays communications between the low-earth orbit communication satellite and a mobile communication terminal on the ground or on water. The flying relay station has a function for communicating with the mobile communication terminal via radio waves and a function for communicating with the low-earth orbit communication satellite via laser light. In this mobile satellite communication system, if a single flying relay station cannot handle an increase in communication volume from multiple mobile communication terminals within the same communication area, multiple flying relay stations are placed in the sky within the same communication area, and the communications between the low-earth orbit communication satellite and the mobile communication terminals are shared and relayed by the multiple flying relay stations.

[0005] Patent Document 3 also discloses that a low-orbit communication satellite may be equipped with multiple optical antennas for relay station communication in advance, depending on the number of corresponding flying relay stations, so that optical communication with multiple flying relay stations can be performed simultaneously in parallel (for example, paragraph

[0034] of Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-132045 [Patent Document 2] Special Publication No. 2015-524629 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-13513 Summary of the Invention [Problem to be solved by the invention]

[0007] However, if we assume that there are multiple artificial satellites (hereinafter simply referred to as "satellites") in space, it is not realistic for each of these multiple satellites to communicate independently with a ground station. For this reason, as shown in Figure 17, UA relay satellite S relays communications between the satellite and a ground station G on Earth E. R is established, and multiple satellites S U1 ,S U2 ,S U3 Each of the relay satellites S R It is assumed that the relay satellite S communicates with the ground station G via the relay satellite S as shown in FIG. R is a set of multiple satellites S U1 ,S U2 ,S U3 and receives the data D1, D2, and D3 transmitted from each of the R is transmitted to ground station G.

[0008] In this case, relay satellite S R The amount of data communication per unit time in the communication line between the relay satellite S and the ground station G (hereinafter simply referred to as the "data rate") is physically limited. R The data rate of the communication line between the relay satellite S and the ground station G must be below a predetermined value. R There are multiple satellites S U1 ,S U2 ,S U3 Even if data is received from each of the above, it may not be possible to transmit all of the data to ground station G at once.

[0009] Meanwhile, relay satellite S R The data rate of the communication line between the relay satellite S and the ground station G is high, and a lot of data is transmitted to the relay satellite S. R In some cases, it is possible to simultaneously transmit from the relay satellite S to the ground station G. R In some cases, it is possible to transmit data received from two or more satellites to the ground station G at once. In this case, the satellite to be communicated with the ground station G is one satellite S. U1 If we limit it to this period, other satellites U2 ,S U3 cannot communicate with ground station G. As a result, relay satellite S R Although there is sufficient capacity in the communication line between the satellite and ground station G, the utilization rate of the communication line is low.

[0010] The above problem can be solved by relay satellite S R The destination of data from the relay satellite S is not limited to the ground station G. R However, similar problems can occur when transmitting data to other devices, such as flying objects in the stratosphere or troposphere.

[0011] The technologies of the above Patent Documents 1 to 3 do not take into consideration the limit value of the data rate between a relay satellite and other devices such as a ground station. For example, Patent Document 3 discloses that a low-earth orbit communication satellite performs optical communication with a plurality of flying relay stations simultaneously and in parallel, but does not take into consideration the limit value of the data rate between the relay satellite and other devices.

[0012] For this reason, the conventional technology has a problem in that when a relay satellite relays communications between multiple satellites and other devices such as a ground station, it is not possible to transmit data from more satellites to other devices while satisfying the data rate limit between the relay satellite and other devices.

[0013] The present disclosure has been made in consideration of the above circumstances, and provides a communication control device, a communication control method, a communication control program, a communication control system, a relay satellite, and a satellite system that, when a relay satellite relays communications between multiple satellites and other devices, can transmit data from more satellites to other devices while satisfying the data rate limit between the relay satellite and other devices. [Means for solving the problem]

[0014] A first aspect of the present disclosure is a communication control device that relays communications between multiple satellites and other devices, and includes multiple optical communication units that can perform optical communication in parallel with the multiple satellites, an equipment communication unit that communicates with the other devices, a setting unit that sets a first data rate that is the sum of limit values ​​of data communication volume per unit time between the multiple satellites and the multiple optical communication units and a second data rate that is the limit value of data communication volume per unit time between the communication control device and the other devices, and a control unit that controls the multiple optical communication units and the equipment communication units so that data received by the multiple optical communication units from the multiple satellites at the first data rate is relayed in parallel to the other devices at the second data rate.

[0015] A communication control device of a second aspect of the present disclosure is a communication control device that includes a control unit that controls communication between a relay satellite and multiple satellites so that, when the relay satellite relays communication between multiple satellites and other devices, the sum of data rates representing the amount of communication per unit time between the multiple satellites and the relay satellite is equal to or less than the limit value of the data rate between the relay satellite and other devices. [Effects of the Invention]

[0016] According to the present disclosure, when a relay satellite relays communications between multiple satellites and other devices, it is possible to obtain the effect of being able to transmit data from more satellites to other devices while satisfying the limit value of the data rate between the relay satellite and other devices. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a satellite system according to an embodiment of the present invention. [Figure 2] 1 is a diagram illustrating an example of a schematic configuration of a communication control system according to first and second embodiments. [Figure 3] FIG. 10 is a diagram illustrating communication time. [Figure 4] FIG. 10 is a diagram illustrating communication time. [Figure 5]FIG. 2 is a diagram for explaining a signal switching circuit. [Figure 6] FIG. 2 is a diagram for explaining a signal switching circuit. [Figure 7] FIG. 2 is a diagram for explaining a signal switching circuit. [Figure 8] FIG. 2 is a diagram for explaining a signal switching circuit. [Figure 8A] FIG. 10 is a diagram illustrating an example of the configuration of a communication control system in which the relay communication device is an optical communication device. [Figure 8B] 10 is a diagram showing an example of the configuration of a communication control system in which an optical communication device 14C among a plurality of optical communication devices 14 is a relay communication device. [Figure 9] FIG. 1 is a schematic block diagram of a computer that functions as a communication control device. [Figure 10] FIG. 2 is a diagram illustrating a process executed by a communication control device. [Figure 11] FIG. 2 is a diagram for explaining satellite capture. [Figure 12] FIG. 2 is a diagram for explaining satellite capture. [Figure 13] FIG. 2 is a diagram for explaining satellite capture. [Figure 14] FIG. 2 is a diagram for explaining satellite capture. [Figure 15] FIG. 2 is a diagram illustrating a process executed by a communication control device. [Figure 16] FIG. 10 is a diagram for explaining a modified example of communication. [Figure 17] FIG. 1 is a diagram for explaining a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0019] <Satellite system of the first embodiment>

[0020] FIG. 1 is a diagram showing a satellite system 1 according to this embodiment. As shown in FIG. 1, the satellite system 1 according to this embodiment includes a relay satellite 2, satellites 3A, 3B, and 3C (hereinafter simply referred to as "user satellites") that are different from the relay satellite 2, and a ground station 4, which is a radio station on Earth. The relay satellite 2 and the user satellites 3A, 3B, and 3C are artificial satellites. The ground station 4 is an example of other equipment. The ground station 4, which is installed on the ground, is an example of an earth station that performs wireless communication or optical communication, and when multiple ground stations 4 are installed, the term "ground station 4" may be used as a general term for all of them.

[0021] Each of the user satellites 3A, 3B, and 3C orbits in a first orbit in outer space. The relay satellite 2 orbits in a second orbit in outer space. The altitudes of the first and second orbits from the Earth's surface are lower than the altitude of a geosynchronous orbit from the Earth's surface (approximately 36,000 km). A geostationary orbit (GEO) is an example of a geosynchronous orbit. The altitude of the second orbit from the Earth's surface is higher than the altitude of the first orbit from the Earth's surface. The first orbit is, for example, a low Earth orbit (LEO). The altitude of the apogee of the low Earth orbit from the Earth's surface is, for example, 20 km to 2,000 km above the Earth's surface. The second orbit is, for example, a medium Earth orbit (MEO). The altitude of the apogee of the medium Earth orbit from the Earth's surface is, for example, 1,000 km to approximately 36,0000 km above the Earth's surface.

[0022] Each of the multiple user satellites 3A, 3B, and 3C communicates wirelessly with the relay satellite 2 and performs data communication with the ground station 4 via the relay satellite 2. The relay satellite 2 communicates data with the multiple user satellites 3A, 3B, and 3C while simultaneously communicating data with the ground station 4 in parallel, thereby relaying data communication between the multiple user satellites 3A, 3B, and 3C and the ground station 4 in real time. The ground station 4 and the server 6 are connected via a network 5, such as the Internet, and the server 6 receives data acquired by the user satellites 3A, 3B, and 3C via the ground station 4. This allows the server 6 to obtain data acquired by the user satellites 3A, 3B, and 3C while on the ground, and also has the functions necessary to operate the satellite system of FIG. 1 . Note that when referring to any one of the multiple user satellites 3A, 3B, and 3C, it will be referred to simply as the "user satellite 3."

[0023] FIG. 2 is a diagram illustrating a detailed configuration example of a communication control system 12 according to an embodiment. As illustrated in FIG. 2, the communication control system 12 includes multiple optical communication devices 14A, 14B, and 14C, a communication control device 16, a signal switching circuit 18, a data multiplexing circuit 19A, a multiplexed data demultiplexing circuit 19B, and a high-frequency radio device 20. The communication control system 12 is mounted on a relay satellite 2. When referring to any one of the multiple optical communication devices 14A, 14B, and 14C, it is simply referred to as the "optical communication device 14." The number of user satellites 3 is not limited to three as illustrated in FIG. 2 and may exceed three. Furthermore, the number of user satellites 3 does not need to be the same as the number of optical communication devices 14 and may exceed the number of optical communication devices 14. The user satellite 3 may be part of a satellite constellation in which multiple satellites work together to achieve a single function or service.

[0024] (Optical communication equipment)

[0025] Each of the multiple optical communication devices 14A, 14B, and 14C includes an optical telescope 140A, an optical receiver 142A, and an optical transmitter 144A, as shown in the optical communication device 14A in FIG. 2. The configurations of the optical communication devices 14B and 14C shown in FIG. 2 are similar to that of the optical communication device 14A. Therefore, only the configuration of the optical communication device 14A will be described below. Note that the optical communication device is an example of an optical communication unit in the present disclosure.

[0026] The optical telescope 140A transmits and receives laser light to and from the user satellites 3A, 3B, and 3C. Note that the user satellite with which the optical communicator 14A optically communicates is not limited to the user satellite 3A. The optical communicator 14A can also optically communicate with the user satellites 3B and 3C. The optical telescope 140A has a window (not shown) that serves as an entrance and exit for the laser light. The optical telescope 140A also has a beam steering mirror (not shown). The beam steering mirror adjusts the optical path.

[0027] Optical telescope 140A outputs laser light received from other satellites to optical receiver 142A (described later) via a beam steering mirror. Optical telescope 140A also outputs laser light output from optical transmitter 144A (described later) to other satellites via a beam steering mirror.

[0028] The optical receiver 142A optically demodulates the laser light output from the optical telescope 140A to obtain a digital electrical signal corresponding to the laser light received by the optical telescope 140A. The optical receiver 142A then outputs the digital electrical signal to the high-frequency radio device 20, which will be described later.

[0029] The optical transmitter 144A obtains laser light corresponding to the digital electrical signal by optically modulating the digital electrical signal output from the high-frequency radio device 20, which will be described later. Then, the optical transmitter 144A outputs the laser light to the optical telescope 140A.

[0030] (Communication control device)

[0031] As shown in FIG. 2, the communication control device 16 includes a setting unit 160 and a control unit 162.

[0032] The data rate at which the relay satellite 2 transmits data to the ground station 4 is physically limited. Specifically, the data rate at which the relay satellite 2 transmits data to the ground station 4 is required to be equal to or lower than a predetermined limit value. Therefore, even if the relay satellite 2 receives data in parallel from each of the multiple user satellites 3A, 3B, and 3C, it may not be possible to transmit all of the data to the ground station 4 at one time.

[0033] On the other hand, if there is a margin in the data rate limit value of the communication line between the relay satellite 2 and the ground station 4, it may be possible to transmit data transmitted from two or more user satellites 3 at once to the ground station 4. In this case, if the number of optical communication devices 14 for the user satellite 3 that relays and transmits data from the relay satellite 2 to the ground station 4 is limited to one, the availability of the communication line between the relay satellite 2 and the ground station 4 will be low, which is not appropriate.

[0034] Furthermore, if the optical communication device 14 that relays and transmits data to the ground station 4 is limited to one device that communicates with, for example, the user satellite 3A, the other user satellites 3B and 3C will not be able to transmit data to the ground station 4 until the communication between the user satellite 3A and the relay satellite 2 is completed.

[0035] Therefore, the communication control device 16 of this embodiment controls the communications between the multiple optical communication devices 14A, 14B, 14C and the multiple user satellites 3A, 3B, 3C when the relay satellite 2 relays communications between the multiple user satellites 3A, 3B, 3C and the ground station 4 so that the sum of the data rates between the multiple user satellites 3A, 3B, 3C and the multiple optical communication devices 14A, 14B, 14C is equal to or less than the limit value of the data rate between the high frequency radio device 20 and the ground station 4. Specifically, the communication control device 16 of this embodiment controls the communications so that the sum of the data rates between the multiple user satellites 3A, 3B, 3C and the multiple optical communication devices 14A, 14B, 14C is equal to or less than the limit value of the data rate between the high frequency radio device 20 and the ground station 4 when the multiple optical communication devices 14A, 14B, 14C receive data transmitted from the multiple user satellites 3A, 3B, 3C.

[0036] More specifically, first, the communication control device 16 sets the number of user satellites 3 that will perform optical communication in parallel with the relay satellite 2 so that the data rate between the relay satellite 2 and the ground station 4 is equal to or less than the limit value. Then, while the optical communication device 14 is receiving data from the user satellite 3 that is the target of optical communication, the communication control device 16 controls each device so that the received data is transmitted from the relay satellite 2 to the ground station 4.

[0037] The specific details will be explained below.

[0038] The total number of optical communication devices installed on relay satellite 2 is N U [units], and the limit value of the data rate of the data communication line between one user satellite 3 and one optical communication device 14 is R U [bit / sec], the time required for one optical communication device 14 to establish a communication line for data communication with one user satellite 3 is X aq [sec], and the limit value of the data rate in data communication when data is transmitted from relay satellite 2 to ground station 4 is R G [bit / sec]. In this case, R G and R UThe condition between and is expressed by the following formula (1). Note that the data rate limit value here may be not only the data rate limit value in the design specifications of the optical communication device 14, but also the data rate limit value in operation. If the data rate limit values ​​of the optical communication devices 14 are not the same, a fixed value that is equal to or smaller than the maximum value among them is set as R G It may be set as

[0039]

number

[0040] In addition, the maximum number of optical communication devices that can simultaneously perform optical communication is N op is set by the following equation (2).

[0041]

number

[0042] In this case, N op <N U When this is true, the communication time T co [sec] is set according to the following equation (3): This allows data from more user satellites 3 to be transmitted to the ground station 4.

[0043]

number

[0044] For example, the maximum number of optical communication devices that can simultaneously perform optical communication is N opIn this case, for example, the communication control device 16 calculates the communication time T co After the optical communication of [sec] is completed, the communication time T co The optical communication devices 14A, 14B, and 14C are controlled so that optical communication is performed for [sec].

[0045] Furthermore, for example, if the maximum number of optical communication devices that simultaneously perform optical communication is N op In this case, for example, the communication control device 16 calculates the communication time T co During optical communication of [sec] However, the communication time T co [sec] optical communication is performed The optical communication devices 14A, 14B, and 14C are controlled so that the optical communication devices 14A, 14B, and 14C can be displayed.

[0046] Maximum number of optical communication devices that can simultaneously perform optical communication: N op is calculated according to the above formula (2), and as a result, the sum of the data rates between the multiple user satellites 3A, 3B, 3C and the multiple optical communication devices 14A, 14B, 14C is equal to or less than the limit value of the data rate between the relay satellite 2 and the ground station 4. This makes it possible to transmit data from more user satellites 3 to the ground station 4 at one time while satisfying the limit value of the data rate between the relay satellite 2 and the ground station 4. It also makes it possible to improve the availability of the communication line between the relay satellite 2 and the ground station 4. The sum of the data rates between the multiple user satellites 3A, 3B, 3C and the multiple optical communication devices 14A, 14B, 14C is an example of the first data rate in the present disclosure. In addition, the limit value R of the amount of data communication per unit time between the communication control device 16 and the ground station 4 is G [bit / sec] is an example of the second data rate of the present disclosure.

[0047] The communication control device 16 determines the timing to start optical communication between one optical communication device 14 and one user satellite 3 based on the time T dif [sec] As a result, the communication time T co [sec] is distributed It is divided.

[0048]

number

[0049] FIG. 3 shows the case where the number of optical communication devices mounted on the relay satellite 2 is 3 (i.e., N U = 3), the maximum number of optical communication devices that simultaneously perform optical communication is N op 3 is an example of a control sequence when the number of optical communication devices performing optical communication, N op = 1, so T dif =T co 3, for example, the timing at which the optical communication device 14B starts communication is after the optical communication device 14A has finished optical communication.

[0050] 3, the high frequency radio equipment 20 of the relay satellite 2 transmits the data received by the optical communication equipment 14 from the user satellite 3 in parallel to the ground station 4 and relays it in real time. That is, the communication time T co [sec] While this optical communication is being carried out, the high frequency radio device 20 starts transmitting the received data to the ground station 4 .

[0051] For example, as shown in FIG. 3 , data received by the optical communication device 14A from the user satellite 3 between time t0 and time t1 is transmitted to the ground station 4 by the high-frequency radio device 20 between time t0 and time t1. Furthermore, data received by the optical communication device 14B from the user satellite 3 between time t1 and time t2 is transmitted to the ground station 4 by the high-frequency radio device 20 between time t1 and time t2. Furthermore, data received by the optical communication device 14C from the user satellite 3 between time t2 and time t3 is transmitted to the ground station 4 by the high-frequency radio device 20 between time t2 and time t3. Note that there is a slight difference between the time period when the optical communication device 14 receives data and the time when the high-frequency radio device 20 begins transmitting the data to the ground station 4. Furthermore, the optical communication device 14 that performs optical communication with the user satellite 3 is not fixed. For example, the user satellite 3 that performs optical communication with the optical communication device 14A is not fixed to user satellite 3A. For example, the optical communicator 14A may also be in optical communication with the user satellite 3B or the user satellite 3C. For example, the optical communicator 14A may be in optical communication with the first user satellite from time t0 to time t1, and with the second user satellite from time t3 to time t4.

[0052] On the other hand, Figure 4 shows the maximum number of optical communication devices N op 4 is an example of a control sequence when the number of optical communication devices performing optical communication, N op = 2, so T dif =T co Therefore, for example, the timing of starting communication of the optical communication device 14B is T dif =T co This will occur after / 2 has elapsed.

[0053] 4, for example, data received by the optical communication device 14A from the user satellite 3 between time t0 and time t1, and data received by the optical communication device 14C from the user satellite 3 between time t0 and time t1, are transmitted by the high-frequency radio device 20 to the ground station 4 between time t0 and time t1. Furthermore, data received by the optical communication device 14A from the user satellite 3 between time t1 and time t2, and data received by the optical communication device 14B from the user satellite 3 between time t1 and time t2, are transmitted by the high-frequency radio device 20 to the ground station 4 between time t1 and time t2. Furthermore, data received by the optical communication device 14B from the user satellite 3 between time t2 and time t3, and data received by the optical communication device 14C from the user satellite 3 between time t2 and time t3, are transmitted by the high-frequency radio device 20 to the ground station 4 between time t2 and time t3.

[0054] The maximum number of optical communication devices that can simultaneously perform optical communication is N op If the calculation is 3, then N U =N op = 3, and the above formula (3) does not hold. In this case, the control unit 162, which will be described later, can control all of the optical communication devices 14A, 14B, and 14C mounted on the communication control system 12 to perform optical communication simultaneously or at any timing.

[0055] The setting unit 160 sets a limit value R for the amount of data communication per unit time between the plurality of user satellites 3A, 3B, and 3C and the plurality of optical communication devices 14A, 14B, and 14C. U Furthermore, the setting unit 160 sets a first data rate, which is the sum of the limit value R G Next, setting section 160 sets various types of control information based on these data rates.

[0056] First, the setting unit 160 sets the limit value R of the data rate of the optical communication device 14. U and the data rate limit R in the communication line from the relay satellite 2 to the ground station 4. GBased on this, the maximum number of optical communication devices that simultaneously perform optical communication, N, is calculated according to the above formula (2). op Set.

[0057] Next, the setting unit 160 calculates the time X required for the optical communication device 14 to establish a communication link with the user satellite 3. aq and the total number of optical communication devices, N U and the maximum number of optical communication devices that can simultaneously perform optical communication, N op Based on this, the communication time T co The time required for the optical communication device 14 to establish a communication line with the user satellite 3 is set as X aq is set in advance. Alternatively, the time X required for the optical communication device 14 to establish a communication link with the user satellite 3 is aq is calculated as the time required for the relay satellite 2 to capture the user satellite 3. If the time required for the optical communication device 14 to establish a communication link with the user satellite 3 differs for each of the multiple user satellites 3, the maximum time (time) among them is used as X aq It can be set as:

[0058] Next, the setting unit 160 sets the communication time T co and the maximum number of optical communication devices that can simultaneously perform optical communication, N op Based on this, the control time T dif The reference time information in the satellite system 1 is obtained from a positioning satellite such as a GPS. Specifically, the relay satellite 2 and the user satellite 3 of the satellite system 1 perform various controls using the time information obtained from the positioning satellite such as a GPS as the reference time information.

[0059] The control unit 162 controls the optical communication devices 14A, 14B, 14C and the high frequency radio device 20 (described later) so that the data received by the optical communication devices 14A, 14B, 14C from the user satellites 3A, 3B, 3C at the first data rate is relayed in parallel to the ground station 4 at the second data rate. op N so that optical communications can be performed in parallel between one optical communication device 14 and a plurality of user satellites 3. opSpecifically, the control unit 162 controls the optical communication devices 14. co and control time T dif More specifically, the control unit 162 determines whether the communication time between one user satellite 3 among the plurality of user satellites 3A, 3B, and 3C and one optical communication device 14 among the plurality of optical communication devices 14A, 14B, and 14C is communication time T co Furthermore, the control unit 162 controls the optical communication device 14 so that the control time T dif When the time has elapsed, control is performed so that communication is started between one user satellite 3 among the plurality of user satellites 3A, 3B, and 3C and one optical communication device 14 among the plurality of optical communication devices 14A, 14B, and 14C.

[0060] The maximum number of optical communication devices that can simultaneously perform optical communication is N op If the calculation is made as =3, the control unit 162 can control all of the optical communication devices 14A, 14B, and 14C installed in the communication control system 12 to perform optical communication with multiple user satellites 3 simultaneously or at any timing.

[0061] The control unit 162 controls the optical communications of the multiple optical communication devices 14A, 14B, and 14C by outputting control signals to the multiple optical communication devices 14A, 14B, and 14C and the signal switching circuit 18 described later so as to realize the above-mentioned control processing.

[0062] (Signal switching circuit)

[0063] The signal switching circuit 18 switches the signal paths between the multiple optical communication devices 14A, 14B, and 14C and the signal paths between the multiple optical communication devices 14A, 14B, and 14C and the high-frequency radio device 20 described later, in response to a control signal output from the communication control device 16.

[0064] 5 to 8 are diagrams illustrating the signal switching circuit 18. The signal switching circuit 18 switches the path of an electrical signal by changing the internal circuit path in response to a control signal output from the communication control device 16. This switches the signal path between the multiple optical communication devices 14A, 14B, and 14C and the high-frequency radio device 20, which will be described later. For example, as shown in FIG. 5, the signal switching circuit 18 switches the signal path by setting the internal circuit path so that the optical communication devices 14A and 14B are electrically connected to the high-frequency radio device 20. In the example shown in FIG. 5, data is multiplexed by a data multiplexing circuit 19A, or the multiplexed data is demultiplexed by a multiplexed-data demultiplexing circuit 19B so that the optical communication devices 14A and 14B can communicate simultaneously in parallel.

[0065] 6, the signal switching circuit 18 switches the signal path so that the optical communication device 14A and the optical communication device 14C are electrically connected to the high-frequency radio device 20. In the example shown in FIG. 6, data is multiplexed by a data multiplexing circuit 19A and the multiplexed data is demultiplexed by a multiplexed data demultiplexing circuit 19B so that the optical communication device 14A and the optical communication device 14C can communicate simultaneously in parallel.

[0066] 7, the signal switching circuit 18 switches the signal path so that the optical communication device 14A, the optical communication device 14B, and the optical communication device 14C are electrically connected to the high-frequency radio device 20. In the example shown in FIG. 7, data is multiplexed by a data multiplexing circuit 19A and the multiplexed data is demultiplexed by a multiplexed data demultiplexing circuit 19B so that the optical communication device 14A, the optical communication device 14B, and the optical communication device 14C can communicate simultaneously in parallel.

[0067] Furthermore, as shown in Fig. 8, the signal switching circuit 18 switches the signal path so that the optical communication devices 14A and 14B are electrically connected. The example in Fig. 8 is an example in which the relay satellite 2 relays data communications between user satellites. For example, consider a case in which optical communications are performed between the optical communication device 14A and the user satellite 3A, and optical communications are performed between the optical communication device 14B and the user satellite 3B. In this case, as shown in Fig. 8, the optical communication device 14A receives data from the user satellite 3A, and the data is transmitted to the user satellite 3B via the optical communication device 14B. Furthermore, the optical communication device 14B receives data from the user satellite 3B, and the data is transmitted to the user satellite 3A via the optical communication device 14A. In this way, the relay satellite 2 can also relay data communications between user satellites.

[0068] (Data multiplexing circuit and multiplexed data separation circuit)

[0069] The data multiplexing circuit 19A multiplexes data so that optical communication by a plurality of optical communication devices is possible, as shown in Figures 5 to 8. The multiplexed data demultiplexing circuit 19B demultiplexes the multiplexed data so that optical communication by a plurality of optical communication devices is possible, as shown in Figures 5 to 8.

[0070] (High frequency radio)

[0071] 5 to 8 is an example of a relay communication device that enables the relay satellite 2 to communicate with the ground station 4 or the like. The relay communication device is an example of an equipment communication unit of the present disclosure. The high-frequency radio device 20 includes a high-frequency modulation circuit 200, a high-frequency transmitting antenna 201 (see FIG. 2; omitted in FIGS. 5 to 8), a high-frequency transmitter 202, a high-frequency receiving antenna 203 (see FIG. 2; omitted in FIGS. 5 to 8), a high-frequency receiver 204, and a high-frequency demodulation circuit 206. The high-frequency radio device 20 modulates data acquired by the multiple optical communication devices 14A, 14B, and 14C and transmits the data to the ground station 4. The high-frequency radio device 20 also demodulates data transmitted from the ground station 4 and passes the data to the multiple optical communication devices 14A, 14B, and 14C.

[0072] The high frequency modulation circuit 200 modulates the digital electrical signal output from the optical communication device 14 and outputs it to the high frequency transmitter 202 .

[0073] The high frequency transmitter 202 converts the signal modulated by the high frequency modulation circuit 200 into a high frequency signal and amplifies the signal.

[0074] The high frequency transmitting antenna 201 radiates the high frequency output from the high frequency transmitter 202 toward the ground station 4 .

[0075] The high frequency receiving antenna 203 receives the high frequency transmitted from the ground station 4 .

[0076] High frequency receiver 204 extracts a modulated signal from the high frequency received by high frequency receiving antenna 203 and outputs the modulated signal.

[0077] The high frequency demodulation circuit 206 demodulates the modulated signal output from the high frequency receiver 204 and converts it into a digital electrical signal.

[0078] In this embodiment, a case will be described in which a high-frequency radio device 20 is used as an example of a relay communication device, but the relay communication device that performs wireless communication with the ground station 4 may also be an optical communication device. When the relay communication device is an optical communication device, optical communication is performed between the relay satellite 2 and the ground station 4. In this case, data communication is performed in parallel between the multiple user satellites 3 and the multiple optical communication devices 14, and data received by each of the multiple optical communication devices 14 is multiplexed, and optical communication is performed between the optical communication device that is the relay communication device and the ground station 4.

[0079] Fig. 8A shows an example of the configuration of a communication control system in which the relay communication device is an optical communication device. In the case of Fig. 8A, for example, data received by the optical communication device 14A from the user satellite 3A and data received by the optical communication device 14B from the user satellite 3B are multiplexed by a data multiplexing circuit 19A. Then, the optical transmitter 201 and optical telescope 203 of the relay optical communication device 21 transmit the data multiplexed by the data multiplexing circuit 19A to the ground station 4 using optical communications.

[0080] Furthermore, the optical telescope 205 and optical transmitter 207 of the relay optical communication device 21 receive data transmitted by optical communication from the ground station 4. The multiplexed data demultiplexing circuit 19B demultiplexes the data transmitted from the ground station 4. Then, each of the optical communication devices 14A and 14B transmits the data demultiplexed by the multiplexed data demultiplexing circuit 19B to, for example, the user satellite 3A and the user satellite 3B, respectively.

[0081] At least one of the multiple optical communication devices 14 may be a relay communication device that performs data communication with the ground station 4. FIG. 8B shows an example of the configuration of a communication control system in which the optical communication device 14C of the multiple optical communication devices 14 is a relay communication device. In the case of FIG. 8B, the optical communication device 14C functions as a relay communication device, and optical communication is performed between the optical communication device 14C, which is a relay communication device, and the ground station 4. In the case of FIG. 8B, the optical communication device 14C of the multiple optical communication devices 14A, 14B, and 14C serves as a relay communication device, and therefore the number of optical communication devices that perform data communication with the user satellite 3 is reduced by one. Therefore, in the case of FIG. 8B, when data communication is performed in parallel between multiple user satellites 3 and multiple optical communication devices 14, N in the above equation (3) U must be the total number of optical communication devices minus 1.

[0082] The communication control device 16 of the communication control system 12 can be realized, for example, by a computer 70 shown in Fig. 9. The computer 70 includes a central processing unit (CPU) 71, a memory 72 as a temporary storage area, and a non-volatile storage unit 73. The computer 70 also includes an input / output interface (I / F) 74 to which input / output devices (not shown) are connected, and a read / write (R / W) unit 75 that controls reading and writing of data from and to a recording medium. The computer 70 also includes a network interface (I / F) 76 that allows the communication control system 12 to connect to a terrestrial communication system such as the Internet. The CPU 71, memory 72, storage unit 73, input / output I / F 74, R / W unit 75, and network I / F 76 are connected to one another via a bus 77.

[0083] The storage unit 73 can be realized by a hard disk drive (HDD), a solid state drive (SSD), a flash memory, etc. The storage unit 73 as a storage medium stores a program for causing the computer 70 to function. The CPU 71 reads the program from the storage unit 73, expands it in the memory 72, and sequentially executes the processes contained in the program.

[0084] The functions realized by the program can also be realized by, for example, a semiconductor integrated circuit, more specifically, an Application Specific Integrated Circuit (ASIC).

[0085] Furthermore, each device included in the communication control system 12 may also be realized by a computer 70 shown in FIG.

[0086] <Function of communication control system 12>

[0087] Next, a description will be given of the operation of the communication control system 12 of this embodiment. When the communication control system 12 operates and receives an instruction signal instructing the start of optical communications between the multiple user satellites 3A, 3B, and 3C and the relay satellite 2, the communication control device 16 executes a communication control processing routine shown in FIG.

[0088] In step S100, the setting unit 160 sets the limit value R of the data rate of the optical communication device 14. U and the data rate limit R in the communication line from the relay satellite 2 to the ground station 4. G Based on this, the maximum number of optical communication devices that simultaneously perform optical communication, N, is calculated according to the above formula (2). op The setting unit 160 sets the limit value R of the data rate. U and the data rate limit R G These data are acquired by reading them out from a predetermined storage unit in the communication control device 16 or the memory 72.

[0089] In step S102, the setting unit 160 calculates the time X required for the optical communication device 14 to establish a communication link with the user satellite 3. aq and the total number of optical communication devices, N U and the maximum number N of optical communication devices set in step S100. op Based on this, the communication time T co The setting unit 160 sets X aq can be acquired from a predetermined storage unit in the communication control device 16 or the memory 72.

[0090] In step S104, the setting unit 160 sets the communication time T co and the maximum number N of optical communication devices set in step S100. op Based on this, the control time T dif Set.

[0091] In step S106, the control unit 162 determines whether the communication time T coand the control time T set in step S104. dif Based on this, the optical communication devices 14A, 14B, and 14C are controlled.

[0092] Specifically, the control unit 162 determines that the communication time between the user satellite 3A, which is an example of a first satellite, and the optical communication device 14A, which is an example of a first optical communication device, is communication time T co Furthermore, the control unit 162 controls the optical communication device 14A so that the control time T dif When the time has elapsed, control is performed so that communication is started between the user satellite 3B, which is an example of a second satellite, and the optical communication device 14B, which is an example of a second optical communication device.

[0093] As a result, when the relay satellite 2 relays communications between multiple user satellites 3A, 3B, and 3C and the ground station 4, it is possible to transmit data from more user satellites 3 to the ground station 4 while satisfying the data rate limit between the relay satellite 2 and the ground station 4.

[0094] As described above, the communication control device 16 of the communication control system 12 according to the first embodiment controls communications between a relay satellite and multiple satellites so that the sum of data rates representing the amount of communication per unit time between the multiple user satellites and the relay satellite is equal to or less than the limit value of the data rate between the relay satellite and the ground station when the relay satellite relays communications between the multiple user satellites and the ground station. This allows the relay satellite to transmit data from more user satellites to the ground station while satisfying the limit value of the data rate between the relay satellite and the ground station when relaying communications between the multiple user satellites and the ground station.

[0095] Furthermore, by increasing the number of user satellites that communicate simultaneously, the availability of communication lines between the relay satellite and the ground station can be improved.

[0096] <Satellite system of the second embodiment>

[0097] Next, a second embodiment will be described. Note that the configurations of the satellite system and communication control system of the second embodiment are similar to those of the first embodiment, so the same reference numerals are used and the description will be omitted.

[0098] The communication control system of the second embodiment calculates X based on the acquisition time X, which represents the time required for the relay satellite 2 to acquire the user satellite 3. aq and calculates the communication time T co This differs from the first embodiment in that the following is set:

[0099] As shown in the above formula (3), the communication time T co is the time required to establish a communication link between the user satellite 3 and the optical communication device 14, X aq It is calculated based on the following.

[0100] The communication control system of the second embodiment is configured to calculate the time X required to establish a communication line between the user satellite 3 and the optical communication device 14. aq The communication control system of the second embodiment calculates an acquisition time X including the acquisition time X, which represents the time required for the optical communication device 14 to acquire the user satellite 3. aq Depending on the communication time T co Set.

[0101] When establishing a communication link between the user satellite 3 and the optical communication device 14, most of the time is required for the acquisition time X when the optical communication device 14 acquires the user satellite 3. Therefore, the communication control system of the second embodiment calculates the acquisition time X and determines the communication time T co Set.

[0102] The specific details will be explained below.

[0103] In the second embodiment, an example will be described in which the satellite that irradiates the capture signal light is the relay satellite 2, and the satellite that receives the capture signal light is the user satellite 3. Therefore, the following description will be given taking as an example a case in which the relay satellite 2 captures the user satellite 3 with which it will communicate.

[0104] First, the setting unit 160 of the communication control device 16 of the relay satellite 2 calculates a candidate region where the user satellite 3, which is the communication target of the optical communication device 14, may be located. Specifically, the setting unit 160 calculates the candidate region where the user satellite 3 may be located using an existing method based on the orbit calculation of the user satellite 3, the prediction error of the orbit of the user satellite 3, the attitude determination accuracy, and the attitude control accuracy of the user satellite 3, etc. The position where the user satellite 3 may be located is predicted based on the orbit calculation of the user satellite 3, the prediction error of the orbit of the user satellite 3, the attitude determination accuracy, and the attitude control accuracy of the user satellite 3, etc.

[0105] 11 to 13 are diagrams for explaining the acquisition of a user satellite 3 by a relay satellite 2. The acquisition of a user satellite 3 by a relay satellite 2 is composed of a satellite tracking step, a coarse acquisition step of the user satellite 3 by the relay satellite 2, a coarse acquisition step of the relay satellite 2 by the user satellite 3, and a fine acquisition step, as described below. The acquisition method shown in Figures 11 to 13 is a spiral scan method. In the second embodiment, an example will be described in which the satellite acquisition method is the spiral scan method.

[0106] (Satellite tracking step)

[0107] First, the setting unit 160 uses an existing method to calculate a candidate region F in which the user satellite 3 may exist, as shown in Figure 11, based on the orbit calculation results for the user satellite 3, the prediction error of the orbit of the user satellite 3, the attitude determination accuracy of the user satellite 3, the attitude control accuracy, etc.

[0108] (Step of roughly acquiring user satellite 3 by relay satellite 2)

[0109] Next, the control unit 162 controls the optical communication device 14 to orient the optical telescope in a direction along the candidate area F set by the setting unit 160, and controls the optical communication device 14 to output a beam of capture signal light L1. The divergence angle of the beam of capture signal light L1 is usually smaller than that of the candidate area F. Therefore, the control unit 162 of the communication control device 16 of the relay satellite 2 controls the optical communication device 14 to scan the candidate area F with the capture signal light L1, thereby scanning the entire candidate area F.

[0110] 12, a light receiving sensor (not shown) mounted on the user satellite 3 receives the capture signal light L1. The light receiving sensor (not shown) is realized by a known sensor such as a quadrant sensor or a CCD. Then, a control device (not shown) of the user satellite 3 determines the direction of the relay satellite 2 from the output value of the light receiving sensor.

[0111] (Rough acquisition step of relay satellite 2 by user satellite 3)

[0112] 13, the user satellite 3 emits a capture signal light L2 in the direction of the identified relay satellite 2. The optical communication device 14 of the relay satellite 2 receives the capture signal light L2 output from the user satellite 3. The light receiving sensor (not shown) used in this case is also realized by a sensor such as a quadrant sensor or a CCD. The control unit 162 of the communication control device 16 of the relay satellite 2 identifies the direction of the user satellite 3 from the output value of the light receiving sensor.

[0113] (Semen capture step)

[0114] Next, the control unit 162 of the communication control device 16 of the relay satellite 2 controls the optical communication device 14 to stop emitting the capture signal light L1. Then, as shown in FIG. 13 , the control unit 162 of the communication control device 16 emits the capture signal light L3 in the direction of the identified user satellite 3. The user satellite 3 receives the capture signal light L3. This completes the capture of the user satellite 3 by the relay satellite 2.

[0115] The relay satellite 2 and the user satellite 3 then use existing technology to adjust the satellite tracking mechanism and pointing mechanism (not shown) such as the satellite tracking mirror, thereby suppressing vibrations of the satellite itself and disturbances that affect the optical communication line between the satellites, thereby achieving stable tracking.

[0116] Next, an example of a method for calculating the capture time X when the spiral scan method is used will be described.

[0117] In the spiral scan method, as shown in FIG. 11, the capture signal light L1 is scanned in a spiral pattern within the candidate region F. The polar coordinates for capture in the spiral scan are expressed by the following equation (5). Note that ρ in the following equation (5) corresponds to the distance r from the origin in the polar coordinates. Also, θ in the following equation (5) corresponds to the angle in the polar coordinates.

[0118]

number

[0119] 14 shows the signal light L1 in FIG. 11 as viewed from the direction M. Here, I in the above formula (5) θ As shown in FIG. 14, represents the distance between the capture signal beam emitted at a first time representing a certain time and the capture signal beam emitted at a second time representing the next time.

[0120] In order for the trajectory of the capture signal light beam to cover the entire area of ​​the candidate region F, the following equation (6) must be satisfied. b represents the divergence angle of the capture signal light beam.

[0121]

number

[0122] As shown in FIG. 11, when the size of the candidate region F is θ μ (Note that θ μ is the field of view θ of the spiral formed by the time series of the capture signal light. μ ), if the interval time representing the interval between scanning two adjacent capture signal light beams is Δt, the time required to complete scanning the entire candidate area F is t μ is expressed by the following equation (7).

[0123]

number

[0124] An example of a method for setting the interval time Δt is given by the following equation (8): where L represents the communication distance between the relay satellite 2 and the user satellite 3, c represents the speed of light, and t s represents the response time of the light receiving sensor equipped on the relay satellite 2, and F represents the bandwidth of the steering mirror for scanning the signal light. The communication distance L between the relay satellite 2 and the user satellite 3 is calculated based on the candidate region F.

[0125]

number

[0126] The above-mentioned calculation formulas (5) to (8) in the spiral scan method are disclosed in the following reference documents.

[0127] (References) Weiqi Chen, Qi Zhang, Xiangjun Xin, Qinghua Tian, ​​Ying Tao, Yufei Shen, Guixing Cao, Rui Ding, and Yifan Zhang, "Beaconless acquisition tracking and pointing scheme of satellite optical communication in multi-layer satellite networks", Proc. SPIE 11023, Fifth Symposium on Novel Optoelectronic Detection Technology and Application, 110231E (12 March 2019); https: / / doi.org / 10.1117 / 12.2521600

[0128] Therefore, the setting unit 160 of the second embodiment calculates a first time required for the capture signal light L1, which is an example of the first capture signal light output from the relay satellite 2, to be received by the user satellite 3.

[0129] In addition, the setting unit 160 of the second embodiment calculates a second time required for the capture signal light L2 output from the user satellite 3 in response to reception of the capture signal light L1 by the user satellite 3 to be received by the relay satellite 2.

[0130] In addition, the setting unit 160 of the second embodiment calculates a third time required for the capture signal light L3 output from the relay satellite 2 in response to reception of the capture signal light L2 by the relay satellite 2 to be received by the user satellite 3.

[0131] Then, the setting section 160 of the second embodiment calculates the capture time X according to the sum of the first time, the second time, and the third time.

[0132] In the second embodiment, the first time is the scanning time t μ is equivalent to

[0133] Therefore, the setting unit 160 of the second embodiment first determines the speed of light c, the communication distance L between the relay satellite 2 and the user satellite 3, the bandwidth F of the steering mirror for scanning the capture signal light, and the response time t s Based on this, the interval time Δt is calculated according to the above equation (8).

[0134] Next, the setting unit 160 of the second embodiment calculates the calculated interval time Δt and the viewing angle θ of the spiral formed by the time series of the irradiated capturing signal light. μ and the distance I between the capture signal light emitted at the first time and the capture signal light emitted at the second time. θ Based on this, the scanning time t μ Calculate.

[0135] Furthermore, the setting unit 160 of the second embodiment calculates the second time and the third time based on the possible position of the user satellite 3. Note that information such as the possible position of the user satellite 3 at a certain time may be transmitted in advance to the relay satellite 2 from the ground station 4 or the like.

[0136] The setting unit 160 of the second embodiment calculates a scanning time t μ The acquisition time X, which represents the sum of the second time and the third time, is calculated as the time X required for the optical communication device 14 to establish a communication link with the user satellite 3. aq The setting unit 160 sets the scanning time t μ Add a certain time to the sum of the second and third times to get time X. aq may be set.

[0137] <Function of communication control system 12>

[0138] Next, a description will be given of the operation of the communication control system 12 of the second embodiment. When the communication control system 12 operates and receives an instruction signal instructing the start of optical communications between the multiple user satellites 3A, 3B, and 3C and the relay satellite 2, the communication control device 16 executes the capture time setting processing routine shown in FIG.

[0139] In step S200, the setting unit 160 identifies a candidate region F in which the user satellite 3, which is the communication target of the optical communication device 14, may exist.

[0140] In step S202, the setting unit 160 calculates the interval time Δt representing the interval time between irradiation of the capture signal light when scanning the candidate area F with the capture signal light of the spiral scan method for capturing the user satellite 3. Specifically ... relay satellite 3 using the speed of light c, the communication distance L between the relay satellite 2 and the user satellite 3, the bandwidth F of the steering mirror for scanning the capture signal light, and the response time t s Based on this, the interval time Δt is calculated according to the above equation (8).

[0141] In step S204, the setting unit 160 calculates the interval time Δt calculated in step S202 and the viewing angle θ of the spiral formed by the time series of the irradiated capture signal light. μ and the distance I between the capture signal light emitted at the first time and the capture signal light emitted at the second time. θ Based on this, the scanning time t μ Calculate.

[0142] In step S205, the setting unit 160 calculates the second time and the third time based on the possible positions of the user satellites 3, etc.

[0143] In step S206, the setting unit 160 sets the scanning time t μ The sum of the second time and the third time calculated in step S205 is calculated as the time X required for the optical communication device 14 to establish a communication link with the user satellite 3.aq Set as.

[0144] When the execution of the capture time setting process routine shown in Fig. 15 is completed, the communication control device 16 executes the communication control process routine shown in Fig. 10. At this time, the communication time T co When calculating, the time X set by the setting unit 160 of the second embodiment is used. aq Using this, the communication time T co This calculates the communication time T co is set.

[0145] Other configurations and operations of the satellite system and communication control system of the second embodiment are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0146] As described above, the communication control device 16 of the communication control system 12 according to the second embodiment calculates the first time required for the capture signal light L1, which is an example of the first capture signal light output from the relay satellite 2, to be received by the user satellite 3. The communication control device 16 also calculates the second time required for the capture signal light L2, which is output from the user satellite 3 in response to the user satellite 3 receiving the capture signal light L1, to be received by the relay satellite 2. The communication control device 16 calculates the third time required for the user satellite 3 to receive the capture signal light L3, which is output from the relay satellite 2 in response to the user satellite 3 receiving the capture signal light L2. The communication control device 16 calculates the capture time X according to the sum of the first time, the second time, and the third time. The communication control device 16 then calculates the capture time X based on the time X required for the optical communication device 14 to establish a communication link with the user satellite 3. aq As a result, the communication time T co can be set.

[0147] The communication control device 16 identifies a candidate area where the user satellite 3, which is the communication target of the optical communication device, may exist, and calculates the interval time Δt representing the interval time between irradiation of the capture signal light when scanning the candidate area with the capture signal light of the spiral scan method for capturing the user satellite, and the field of view θ of the spiral formed by the time series of the irradiated capture signal light. μ and the distance I between the capture signal light emitted at the first time and the capture signal light emitted at the second time. θ Based on this, the scanning time t μ Then, the communication control device 16 calculates the scanning time t as the first time required for the capture signal light L1, which is an example of the first capture signal light output from the relay satellite 2, to be received by the user satellite 3. μ This allows the time X aq can be calculated.

[0148] The size of candidate region F is the range within which user satellites 3 may exist at a given time, and is determined taking into consideration the orbit prediction accuracy of the user satellite 3 performing optical communications, the attitude control accuracy, the characteristics of the optical communication device, and the like. The actual accuracy of candidate region F depends on the entire system, and therefore varies depending on the user satellite 3. For this reason, at the initial stage of actual operation, candidate region F may be set to be larger, taking into consideration cases where accuracy is poor or errors may occur. Furthermore, since it is expected that the characteristics of the optical communication device 14 and the accuracy of capturing user satellites 3 will improve as operation progresses, it will also be possible to reduce the size of candidate region F at that time.

[0149] Furthermore, the relay satellite 2 can also shorten the predicted acquisition time X by sequentially recording the acquisition time X of the user satellite 3 with which it performs optical communications, and when planning the next communication, updating the candidate region F where the user satellite 3 may be located by taking into account the difference between the position where the user satellite 3 was previously located and acquired and the predicted position of the user satellite 3. In this case, the number of times communication with the user satellite 3 is performed per unit time can be increased.

[0150] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible without departing from the spirit and scope of the present invention.

[0151] For example, in the above-described embodiments, the communication control device 16 controls the multiple optical communication devices 14A, 14B, and 14C so that, while the optical communication device 14 is receiving data from the user satellite 3 with which optical communication is being performed, the received data is transmitted in parallel from the relay satellite 2 to the ground station 4. However, the present invention is not limited to this. For example, the communication control device 16 may temporarily store the data received from the user satellite 3 in a storage unit. For example, the communication control device 16 temporarily stores the data received from the multiple user satellites 3 in a storage unit when the total data rate received from the multiple user satellites 3 exceeds the data rate limit of the communication line between the relay satellite 2 and the ground station 4. Alternatively, for example, the communication control device 16 temporarily stores the data received from the user satellite 3 in a storage unit when the above formula (1) is not satisfied. Then, the communication control device 16 may transmit the data stored in the storage unit to the ground station 4 when there is a capacity available in the communication line between the relay satellite 2 and the ground station 4.

[0152] In the above embodiment, the limit value of the data rate of the communication line between the user satellite 3 and the optical communication device 14 is set to a uniform R U However, the present invention is not limited to this. For example, if the data rate limit value R U may have different values.

[0153] In the above embodiment, the case where there is one high-frequency radio device, which is an example of a relay communication device, has been described as an example, but the present invention is not limited to this. There may be a plurality of high-frequency radio devices, which are an example of a relay communication device. Furthermore, as described above, the relay communication device may be an optical communication device.

[0154] In the above embodiment, the setting unit 160 of the communication control device 16 sets various data and the control unit 162 performs various controls to execute a control sequence for communication by the optical communication device 14 based on the data set by the setting unit 160. However, the present invention is not limited to this. For example, control sequence information for the optical communication device 14 and the relay communication device determined by the terrestrial server 6 may be transmitted in advance to the operators of the relay satellite 2 and the user satellite 3 via the terrestrial station 4 or a server 6 connected to the terrestrial station 4, and the communication control device 16 of the relay satellite 2 may execute the various settings and controls shown in Fig. 10 or 15 based on the control sequence information. In this case, the control sequence information may be determined based on scheduling information that specifies the timing of optical communication between the relay satellite 2 and the user satellite 3, calculated by the operator of the relay satellite 2 based on position information of the user satellite 3 and other information obtained from the operator of the user satellite 3.

[0155] In the above embodiment, the communication time T co Calculate the communication time T co However, the present invention is not limited to this. For example, the communication time T co For a given time T ur In this case, for example, as shown in FIG. 16, the communication time T co Time T ur is added, and the communication between the optical communication device 14B and the optical communication device 14C is performed for a time T ur It will be off by one minute.

[0156] In the second embodiment, the spiral scan method is used to capture a satellite, but the present invention is not limited to this. The satellite may be captured using another method. In this case, it is possible to calculate the capture time X, which indicates the time required for the relay satellite 2 (or the optical communication device 14) to capture the user satellite 3, by calculating at least the first time and the second time among the times calculated in the second embodiment.

[0157] For this reason, for example, the communication control device 16 may calculate the capture time X based on a first time required for the first capture signal light L1 output from the relay satellite 2 to be received by the user satellite 3, and a second time required for the second capture signal light L2 output from the user satellite 3 in response to the user satellite 3's reception of the first capture signal light L1 to be received by the relay satellite 2. For example, the communication control device 16 may calculate the capture time X based on the sum of the first time and the second time.

[0158] Alternatively, for example, the communication control device 16 may calculate the capture time X based on a first time required for the first capture signal light L1 output from the user satellite 3 to be received by the relay satellite 2, and a second time required for the second capture signal light L2 output from the relay satellite 2 in response to the reception of the first capture signal light L1 by the relay satellite 2 to be received by the user satellite 3. For example, the communication control device 16 may calculate the capture time X based on the sum of the first time and the second time.

[0159] In the above embodiment, the multiple satellites are user satellites, but this is not limiting. For example, at least one of the multiple satellites may be another relay satellite.

[0160] In the above embodiment, the relay satellite 2 relays communications between multiple user satellites 3 and the earth station 4, but this is not limiting. Instead of the earth station 4, another earth station (for example, a radio station established on the Earth's surface or in the Earth's atmosphere, which may be a mobile station) that performs wireless communications with the relay satellite may be used. In this case, the relay satellite 2 relays communications between multiple user satellites 3 and the earth station. For example, using an earth station established in the stratosphere has the advantage of ensuring stable optical communication time from the relay satellite 2 to the earth station without being affected by the terrestrial communication environment due to weather, etc. Also, instead of the ground station 4, another user satellite or another relay satellite may be used. In this case, the relay satellite 2 relays communications between multiple user satellites 3 and another user satellite or another relay satellite. In this case, communications may be performed by optical communication, in which case the relay communication device will be an optical communication device.

[0161] Although the present specification has been described as an embodiment in which the program is pre-installed in the storage unit 73 of the computer 70, the program may also be provided by being stored in a computer-readable recording medium. For example, the program may be provided in a form stored in a non-transitory storage medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), or a USB (Universal Serial Bus) memory. The program may also be provided in a form in which it is downloaded from an external device via a network.

[0162] In the above embodiment, the processing that the CPU reads and executes software (programs) may be executed by various processors other than the CPU. In this case, examples of the processor include a PLD (Programmable Logic Device) such as an FPGA (Field-Programmable Gate Array) whose circuit configuration can be changed after manufacturing, and a dedicated electric circuit such as an ASIC (Application Specific Integrated Circuit) which is a processor having a circuit configuration designed exclusively for executing specific processing. Alternatively, examples of the processor include a GPGPU (Generic Programmable Processing Unit). Alternatively, a general-purpose graphics processing unit (GPS) may be used. Each process may be executed by one of these various processors, or by a combination of two or more processors of the same or different types (for example, multiple FPGAs, or a combination of a CPU and an FPGA). The hardware structure of these various processors is, more specifically, an electric circuit that combines circuit elements such as semiconductor elements.

[0163] Furthermore, each process of this embodiment may be implemented by a computer or server equipped with a general-purpose processor and a storage device, and each process may be executed by a program. This program is stored in a storage device, and may be recorded on a recording medium such as a magnetic disk, optical disk, or semiconductor memory, or may be provided via a network. Of course, any other components do not have to be implemented by a single computer or server, and may be distributed across multiple computers connected via a network.

[0164] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

[0165] It should be noted that in the above embodiments, unless there is a description of "only" such as "based on XX only," "depending only on XX," or "in the case of XX only," this specification assumes that additional information may also be taken into consideration. For example, the description "do b when a" does not necessarily mean "always do b when a" unless explicitly stated otherwise.

[0166] Furthermore, even if there is an aspect of a method, program, terminal, device, server, or system (hereinafter referred to as a "method, etc.") that performs an operation different from that described in this specification, each aspect of the disclosed technology is directed to an operation that is identical to one of the operations described in this specification, and the existence of an operation different from that described in this specification does not make the method, etc. outside the scope of each aspect of the disclosed technology.

[0167] The following supplementary notes are disclosed.

[0168] (Appendix 1) a control unit that controls communications between the relay satellite and a plurality of satellites so that, when the relay satellite relays communications between the plurality of satellites and other devices, a sum of data rates representing the amount of communications per unit time between the plurality of satellites and the relay satellite is equal to or less than a limit value of the data rate between the relay satellite and the other devices; Communications control device.

[0169] (Appendix 2) the relay satellite includes a plurality of optical communication devices that perform optical communication with the plurality of satellites, and an equipment communication device that performs communication with the other equipment, the control unit controls communications between the plurality of optical communication devices and the plurality of satellites so that the sum of the data rates between the plurality of satellites and the plurality of optical communication devices is equal to or less than a limit value of the data rate between the device communication device and the other device. 2. The communication control device of claim 1.

[0170] (Appendix 3) The data rate limit value R of the communication line between the satellite and the optical communication device U and a limit value R of the data rate in the communication line between the communication device for the device and the other device. G Based on this, the number N of optical communication devices that simultaneously perform optical communication among the plurality of optical communication devices is determined according to the following formula (1): op A setting unit for setting the The control unit is N op N op Controlling optical communication devices 3. The communication control device according to claim 2.

number

[0171] (Appendix 4) The setting unit determines the number N of the optical communication devices. op is the total number of optical communication devices N U If less than the number N of optical communication devices op and the time X required to establish a communication line between the satellite and the optical communication device. aq and the total number of optical communication devices N U Based on this, a communication time T representing the time for communication between the satellite and the optical communication device is calculated according to the following equation (2): co Further set The communication time T co and the number of optical communication devices N op Based on this, the control time T dif Further set The control unit determines the communication time T co and the control time T dif Based on this, the communication time between a first satellite of the plurality of satellites and a first optical communication device of the plurality of optical communication devices is determined to be the communication time T co and the control time T difand controlling the communication between a second satellite of the plurality of satellites and a second optical communication device of the plurality of optical communication devices to start when the time elapses. 4. The communication control device according to claim 3.

number

[0172] (Appendix 5) The time required to establish a communication line between the satellite and the optical communication device is X aq includes an acquisition time X that represents the time required for the optical communication device to acquire the satellite, The setting unit sets the time X including the capture time X. aq In response to the communication time T co Set 5. The communication control device according to claim 4.

[0173] (Appendix 6) The setting unit calculating the capture time X according to a first time required for a first capture signal light output from the relay satellite to be received by the satellite, and a second time required for a second capture signal light output from the satellite in response to the reception of the first capture signal light by the satellite, The time X including the capture time X aq In response to the communication time T co Set 6. The communication control device according to claim 5.

[0174] (Appendix 7) The setting unit calculating the capture time X according to a first time required for the first capture signal light output from the satellite to be received by the relay satellite, and a second time required for the second capture signal light output from the relay satellite in response to the reception of the first capture signal light by the relay satellite, The time X including the capture time X aq In response to the communication time T co Set 6. The communication control device according to claim 5.

[0175] (Appendix 8) At least one satellite among the plurality of satellites is another relay satellite. 8. A communication control device according to any one of Supplementary notes 1 to 7.

[0176] (Appendix 9) The other device is at least one of an earth station and a ground station that communicates wirelessly with the relay satellite. 10. A communication control device according to any one of Supplementary note 2 to Supplementary note 8.

[0177] (Appendix 10) the device communication device for communicating with the other device is an optical communication device, The other device is at least one of an earth station, a ground station, a satellite, and another relay satellite that performs optical communication with the relay satellite. 10. A communication control device according to any one of Supplementary note 2 to Supplementary note 8.

[0178] (Appendix 11) A communication control method including each process executed by the communication control device according to any one of Supplementary Note 1 to Supplementary Note 10.

[0179] (Appendix 12) A communication control program for causing a computer to function as each unit of the communication control device according to any one of Supplementary Note 1 to Supplementary Note 10.

[0180] (Appendix 13) a plurality of optical communication devices that perform optical communication with a plurality of satellites; a ground communication device for communicating with a ground station; A communication control device according to any one of Supplementary Note 1 to Supplementary Note 10; A communication control system including:

[0181] (Appendix 14) A relay satellite equipped with a communications control system as described in Appendix 13.

[0182] (Appendix 15) Multiple satellites and relay satellites, A ground station and A communication control device according to any one of Supplementary Note 1 to Supplementary Note 10; satellite systems, including [Explanation of symbols]

[0183] 1. Satellite Systems 2. Relay satellite 3A,3B,3C User satellite 4. Ground Station 12 Communication Control System 14A,14B,14C Optical communication equipment 16 Communication control device 18 Signal switching circuit 20 High frequency radio 70 Computer

Claims

1. a control unit that controls communications between the relay satellite and a plurality of satellites so that, when the relay satellite relays communications between the plurality of satellites and other devices, a sum of data rates representing the amount of communications per unit time between the plurality of satellites and the relay satellite is equal to or less than a limit value of the data rate between the relay satellite and the other devices; Communications control device.

2. the relay satellite includes a plurality of optical communication devices that perform optical communication with the plurality of satellites, and an equipment communication device that performs communication with the other equipment, the control unit controls communications between the plurality of optical communication devices and the plurality of satellites so that the sum of the data rates between the plurality of satellites and the plurality of optical communication devices is equal to or less than a limit value of the data rate between the device communication device and the other device. The communication control device according to claim 1 .

3. The data rate limit value R of the communication line between the satellite and the optical communication device Ｕ and a limit value R of the data rate in the communication line between the device communication unit and the other device. Ｇ Based on this, the number N of optical communication devices that simultaneously perform optical communication among the plurality of optical communication devices is determined according to the following formula (1): ｏｐ A setting unit for setting the The control unit is N ｏｐ N so that communication can be performed between one optical communication device and multiple satellites. ｏｐ Controlling optical communication devices The communication control device according to claim 2 . [Equation 1] （１）

4. The setting unit determines the number N of the optical communication devices. ｏｐ is the total number N of the optical communication devices Ｕ If it is less than the number N of the optical communication devices ｏｐ and the time X required to establish a communication line between the satellite and the optical communication device. ａｑ and the total number N of the optical communication devices. Ｕ Based on this, a communication time T representing the time for communication between the satellite and the optical communication device is calculated according to the following equation (2): ｃｏ Further set The communication time T ｃｏ and the number N of the optical communication devices ｏｐ Based on this, the control time T ｄｉｆ Further set The control unit determines the communication time T ｃｏ and the control time T ｄｉｆ Based on this, the communication time between a first satellite of the plurality of satellites and a first optical communication device of the plurality of optical communication devices is determined to be equal to or less than the communication time T ｃｏ and the control time T ｄｉｆ and controlling the communication between a second satellite of the plurality of satellites and a second optical communication device of the plurality of optical communication devices to start when the time elapses. The communication control device according to claim 3 . [Equation 2] （２） 【number】 （３）

5. The time required to establish a communication line between the satellite and the optical communication device is X ａｑ includes an acquisition time X that represents the time required for the optical communication device to acquire the satellite, The setting unit sets the time X including the capture time X. ａｑ In response to this, the communication time T ｃｏ Set The communication control device according to claim 4.

6. The setting unit calculating the capture time X according to a first time required for a first capture signal light output from the relay satellite to be received by the satellite, and a second time required for a second capture signal light output from the satellite in response to the reception of the first capture signal light by the satellite, The time X including the capture time X ａｑ In response to this, the communication time T ｃｏ Set The communication control device according to claim 5 .

7. The setting unit calculating the capture time X according to a first time required for the first capture signal light output from the satellite to be received by the relay satellite, and a second time required for the second capture signal light output from the relay satellite in response to the reception of the first capture signal light by the relay satellite, The time X including the capture time X ａｑ In response to this, the communication time T ｃｏ Set The communication control device according to claim 5 .

8. At least one satellite among the plurality of satellites is another relay satellite. The communication control device according to any one of claims 1 to 7.

9. the other device is at least one of an earth station and a ground station that communicates wirelessly with the relay satellite; The communication control device according to any one of claims 2 to 8.

10. the device communication device for communicating with the other device is an optical communication device, the other device is at least one of an earth station, a ground station, a satellite, and another relay satellite, which is in optical communication with the relay satellite; The communication control device according to any one of claims 2 to 8.

11. A communication control method including each process executed by the communication control device according to any one of claims 1 to 10.

12. A communication control program for causing a computer to function as each unit of the communication control device according to any one of claims 1 to 10.

13. a plurality of optical communication devices that perform optical communication with a plurality of satellites; a ground communication device for communicating with a ground station; A communication control device according to any one of claims 1 to 10; A communication control system including:

14. A relay satellite equipped with the communication control system according to claim 13.

15. Multiple satellites and relay satellites, A ground station and A communication control device according to any one of claims 1 to 10; satellite systems, including

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