Communication satellite, constituent satellite, artificial satellite, communication satellite constellation, satellite constellation, and satellite

Abstract

To secure a communication environment between a watching satellite and a ground facility in a group of earth orbiting satellites, and to enable information transfer between a user satellite and the ground facility.SOLUTION: A communication satellite 401 is used for a satellite watching system in which a watching satellite and a watching center perform information transfer through a group of communication satellites. The communication satellite 401 includes a first communication device 41 to perform communication with a ground facility and three second communication devices 42 to perform communication among infrastructure satellites. The communication satellite 401 performs communication with a communication satellite flying on the same orbital plane, the watching satellite, or a user satellite simultaneously.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present disclosure relates to ground facilities, communications satellites, constituent satellites, artificial satellites, communications satellite constellations, satellite constellations, and satellites. [Background technology]

[0002] Social infrastructure using satellites has become a part of our daily lives, such as sending and receiving information to remote or distant areas via communication satellites, weather forecasting using images from the Himawari meteorological satellite, and utilizing geospatial information from quasi-zenith positioning satellites. These practical satellite constellations have become critical infrastructures that are indispensable to our daily lives. On the other hand, the increasing number of objects in the space environment is increasing the risk of hazardous events involving the failure or loss of critical infrastructure due to factors such as debris collisions. Therefore, there is a need for a mechanism to monitor critical infrastructure and take action to avoid danger if necessary.

[0003] Patent Document 1 discloses a method for observing space debris in a space where sunlight is backlit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-218834 A Summary of the Invention [Problem to be solved by the invention]

[0005] A problem with satellites flying in low earth orbit (LEO) is that if an emergency occurs and an infrastructure satellite is flying on the other side of the Earth, it is not possible to ensure a communication environment with the monitoring center. A low earth orbit is, for example, an orbit with an altitude between 500km and 2000km. LEO is an abbreviation for Low Earth Orbit. Patent Document 1 does not disclose a method for monitoring critical infrastructure in Earth orbit.

[0006] An object of the present disclosure is to ensure a communication environment between a monitoring satellite and a monitoring center in a constellation of satellites orbiting the Earth, and to enable the exchange of information between a user satellite and ground equipment. [Means for solving the problem]

[0007] The present disclosure A critical infrastructure, which is a social infrastructure in outer space, is a critical infrastructure consisting of a group of infrastructure satellites that fly in a low earth orbit (LEO) with an orbital altitude of 500 km or more and 2000 km or less; A monitoring satellite group consisting of monitoring satellites that fly in an orbit at an altitude of 2000 km or less and monitor the infrastructure satellite group and perform on-orbit services; a ground facility installed on the ground and configured to transmit and receive information to and from each infrastructure satellite of the infrastructure satellite group; A monitoring center is installed on the ground and transmits and receives information to and from the monitoring satellite. Equipped with the infrastructure satellite constellation includes a communications satellite constellation of communications satellites; The communications satellites include: The satellites fly in an evenly spaced orbit with an orbital altitude and inclination that results in a sun-synchronous orbit that completes an integral number of revolutions per day. The communications satellite, It communicates with the communications satellites flying in front and behind it, The communications satellites include: a first satellite in communication with the ground facility; a second satellite communicating with the monitoring satellite; A third satellite that will only communicate with the communications satellites flying in front and behind it. Equipped with The monitoring satellite and the monitoring center are: A communication satellite used in a satellite monitoring system that transmits and receives information via the group of communication satellites, A first communication device that communicates with the ground equipment; three second communication devices for communicating among the infrastructure satellites; Equipped with It communicates simultaneously with communication satellites, monitoring satellites, and user satellites that fly in the same orbital plane. Effect of the Invention

[0008] The communication satellite according to the present disclosure can transmit information communicated with a user satellite to ground facilities in real time, which has the effect of enabling information exchange between a user satellite and ground facilities even in a situation where there are only a few satellites flying in the same orbital plane during the construction of critical infrastructure. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the overall configuration of a satellite monitoring system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration example of a watching center according to the first embodiment. [Diagram 3] FIG. 2 is a diagram showing a configuration example of a satellite, which is an example of a space object, according to the first embodiment. [Figure 4] FIG. 2 is a diagram showing a configuration example of a communication satellite according to the first embodiment. [Diagram 5] FIG. 2 is a diagram showing an example of the configuration of an observation satellite according to the first embodiment. [Figure 6] FIG. 4 is a diagram showing another example of the configuration of the observation satellite according to the first embodiment. [Figure 7]FIG. 1 is a diagram showing a configuration example of a satellite monitoring system according to a first embodiment. [Figure 8] FIG. 3 is a diagram showing a configuration example 3 of a communications satellite constellation according to the first embodiment. [Figure 9] FIG. 4 is a diagram showing a fourth configuration example of a communications satellite constellation according to the first embodiment. [Figure 10] FIG. 2 is a diagram showing a communication system of a communication satellite group according to the first embodiment. [Figure 11] FIG. 11 is a diagram showing an example of the configuration of a satellite information transmission system according to a second embodiment. [Figure 12] FIG. 11 is a diagram showing an example of the overall configuration of a satellite information transmission system according to a second embodiment. [Figure 13] FIG. 11 is a diagram showing a communication system of a communication satellite group according to a second embodiment. [Figure 14] FIG. 11 is a diagram illustrating ground equipment according to a third embodiment. [Figure 15] FIG. 13 is a diagram for explaining a first example of a communications satellite according to a third embodiment. [Figure 16] FIG. 11 is a diagram showing an example of a satellite information transmission system according to a third embodiment. [Figure 17] FIG. 13 is a diagram for explaining a second example of a communication satellite according to the third embodiment. [Figure 18] FIG. 13 is a diagram showing an example of the configuration of a monitoring system according to a fourth embodiment. [Figure 19] FIG. 13 is a diagram showing a configuration example of a first example of a first satellite constellation according to a fourth embodiment. [Figure 20] FIG. 13 is a diagram showing a configuration example of a second example of a first satellite constellation according to a fourth embodiment. [Figure 21] FIG. 13 is a diagram showing a configuration example of a second satellite constellation example 4 according to the fourth embodiment. [Figure 22] FIG. 13 is a diagram showing a first example of a communication method of a satellite information transmission system according to a fifth embodiment. [Diagram 23] FIG. 13 is a diagram showing an example of the overall configuration of a satellite information transmission system according to a fifth embodiment. [Figure 24] FIG. 13 is a diagram showing a sixth example of a communication method of the satellite information transmission system according to the fifth embodiment. [Diagram 25] FIG. 13 is a diagram showing a configuration example of an artificial satellite according to a sixth embodiment. [Figure 26] FIG. 13 is a diagram showing a configuration example of a communications satellite constellation according to a sixth embodiment. [Figure 27] FIG. 23 is a diagram showing an example of the configuration of a satellite constellation according to a sixth embodiment. [Figure 28] FIG. 23 is a diagram showing another example of the configuration of a satellite constellation according to the sixth embodiment. [Figure 29] FIG. 23 is a diagram showing a configuration example of a first example of a satellite information transmission system according to a sixth embodiment. [Diagram 30] FIG. 23 is a diagram showing a configuration example of Example 2 of a satellite information transmission system according to the sixth embodiment. [Diagram 31] FIG. 23 is a diagram showing a configuration example of Example 3 of a satellite information transmission system according to the sixth embodiment. [Diagram 32] FIG. 23 is a diagram showing a configuration example of Example 4 of a satellite information transmission system according to the sixth embodiment. [Diagram 33] FIG. 23 is a diagram showing a configuration example of a fifth example of a satellite information transmission system according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of the embodiments, the description of the same or corresponding parts will be omitted or simplified as appropriate. In addition, the relationship between the sizes of the components in the following drawings may differ from the actual relationship. In addition, in the description of the embodiments, directions or positions such as "upper", "lower", "left", "right", "front", "rear", "front" and "back" may be indicated. These notations are written in this way only for the convenience of explanation, and do not limit the arrangement and orientation of the components such as devices, instruments, or parts.

[0011] Embodiment 1 ***Explanation of the overall configuration of the satellite monitoring system 500*** FIG. 1 is a diagram showing an example of the overall configuration of a satellite monitoring system 500 according to this embodiment. The satellite monitoring system 500 includes a monitoring satellite group 52 that monitors a critical infrastructure 51, and a monitoring center 53. The satellite monitoring system 500 may include a critical infrastructure 51 in addition to the monitoring satellite group 52 and the monitoring center 53. The monitoring satellite 521 is also called a monitoring satellite or a monitoring device.

[0012] Critical Infrastructure 51 is infrastructure in outer space. A specific example of the critical infrastructure 51 is formed by a constellation of satellites that constitute a social infrastructure as follows. - Information exchange with remote or outlying areas via communication satellites -Weather forecast using images from the Himawari weather satellite · Use of geospatial information from quasi-zenith positioning satellites Moreover, the satellites that constitute the critical infrastructure 51 are called infrastructure satellites 511.

[0013] The monitoring satellite group 52 is composed of monitoring satellites 521 that monitor the infrastructure satellites 511 that constitute the critical infrastructure 51 . The monitoring center 53 is installed on the ground and transmits and receives information to and from the monitoring satellites 521 of the monitoring satellite group 52. The monitoring satellite 521 of the monitoring satellite group 52 and the monitoring center 53 exchange information via a communication device provided in the infrastructure satellite 511 .

[0014] The group of satellites constituting the critical infrastructure 51 includes satellites equipped with communication devices for communicating with the monitoring center 53 as infrastructure satellites 511 . The infrastructure satellites 511 include all or some of the communications satellite 401, data relay satellite 402, weather satellite 403, observation satellite 404, first observation and monitoring satellite 405, positioning satellite 406, second observation and monitoring satellite 407, space station 408, lunar planetary exploration satellite 409, exploration satellite 410, and transport vehicle 411. The exploration satellite 410 is an exploration satellite that explores planets or resources other than the moon. The first observation and monitoring satellite 405 is a satellite that is deployed in a high orbit, such as a geostationary orbit or a Molniya orbit, and performs wide-area observation or monitoring of the earth. The second observation and monitoring satellite 407 is, for example, an observation or monitoring satellite for collecting various types of image information on large-scale disasters and other important matters.

[0015] In addition, per-infrastructure ground facilities 54 corresponding to the critical infrastructure 51 are installed on the ground. The per-infrastructure ground facilities 54 are an example of ground facilities that are installed on the ground and transmit and receive information to and from each infrastructure satellite of the infrastructure satellite group 510.

[0016] Due to factors such as debris collisions caused by the increasing number of objects in the space environment, hazardous events that carry the risk of failure or loss of critical infrastructure 51 are increasing. Therefore, a mechanism is needed to monitor critical infrastructure51 and take action to avoid danger if necessary.

[0017] The monitoring satellite group 52 includes an infrastructure satellite 511 equipped with a communication device for communicating with a monitoring center 53 as a monitoring satellite 521 . The monitoring satellite 521 includes all or some of the optical monitoring satellite 421, the radio wave monitoring satellite 423, the infrared monitoring satellite 422, the service satellite 424, and the debris removal satellite 425. The optical monitoring satellite 421 monitors the infrastructure satellite 511 using an optical system. The radio wave monitoring satellite 423 monitors the infrastructure satellite 511 using radio waves. The infrared monitoring satellite 422 monitors the infrastructure satellite 511 using infrared detection. The service satellite 424 provides on-orbit servicing to the infrastructure satellite 511. The debris removal satellite 425 removes debris.

[0018] On-orbit servicing may include all or some of the following: capture, inspection, repair, refueling, transfer, active debris removal (ADR), and laser illumination.

[0019] The monitoring service provided by the monitoring satellite group 52 can be easily understood by analogy with the roles of eyes, ears, hands, and mouth. In order to achieve the objective of visually monitoring the critical infrastructure 51 using satellites, it is effective to visually monitor suspicious objects such as debris using optical telescopes or radar images. Another effective method is to monitor abnormal temperature environments using infrared detection.

[0020] Additionally, a monitoring service that monitors audibly using the ears has the objective of monitoring radio waves in outer space, where sound waves do not propagate. In order to achieve the objective of monitoring critical infrastructure51 audibly using satellites, it is effective to receive radio waves flying around in the vicinity and monitor the radio wave conditions that may cause malfunctions.

[0021] In addition, as an extension of the monitoring service, there is the on-orbit service, which is an analogy to the role of manual operation. On-orbit services include the capture, inspection, and repair of malfunctioning satellites. Also included are refueling satellites that are running low on fuel, mobile services to move the service location, and active orbit de-orbiting (ADR) for satellites that cannot de-orbit on their own after completing their lifespan. Another service includes the use of lasers to monitor the distance to suspicious objects such as debris.

[0022] In this way, it is expected that the monitoring satellite 521 will fulfill the role of eyes, ears, and hands. However, the role of the mouth, i.e., the means of communication to transmit monitoring information 590, is limited, and some ingenuity is required.

[0023] In this embodiment, an infrastructure satellite 511 is used as a monitoring satellite 521 that serves as a port, that is, a monitoring satellite 521 that transmits monitoring information 590. The monitoring satellites 521 include infrastructure satellites 511 as monitoring satellites 521 that play the role of the mouth. The infrastructure satellites 511 also include monitoring satellites 521 that play the role of the mouth. That is, in the satellite monitoring system 500, there are satellites that are monitoring satellites 521 and infrastructure satellites 511. Here, such satellites have been described as infrastructure satellites 511 that mainly play the role of the mouth, but they may also be satellites that play the roles of eyes, ears, and hands.

[0024] 1, the monitoring satellites 521 that perform long-distance communication include a communication satellite 401 and a data relay satellite 402 in a first satellite group 601. Also, the communication satellite 401 is included in a second satellite group 602. Also, a lunar and planetary exploration satellite 409 is included in a third satellite group 603. The monitoring satellites 521 that perform short-distance communication include the meteorological satellites 403 , the positioning satellites 406 , and the observation satellites 404 in the first satellite group 601 .

[0025] As shown in FIG. 1, the satellite monitoring system 500 includes a first satellite group 601, a second satellite group 602, a third satellite group 603, and a monitoring center 53. The first satellite group 601 is made up of satellites flying near a geostationary Earth orbit (GEO) or a quasi-zenith orbit (QZO). The second satellite group 602 is made up of satellites flying near a medium earth orbit (MEO: Medium Earth Orbit) or near a low earth orbit (LEO: Low Earth Orbit). The third satellite group 603 is made up of satellites flying in cislunar space, the space between the moon and the earth, or beyond the moon.

[0026] FIG. 2 shows an example of the configuration of the monitoring center 53 according to this embodiment. The watching center 53 is also referred to as ground equipment 701 installed on the ground. Here, the explanation will be given as ground equipment 701.

[0027] The ground equipment 701 includes a computer. The ground equipment 701 includes a processor 910, as well as other hardware such as a memory 921, an auxiliary storage device 922, an input interface 930, an output interface 940, and a communication device 950. The processor 910 is connected to the other hardware via signal lines and controls the other hardware.

[0028] The ground equipment 701 includes, as examples of functional elements, a monitoring management unit 710 and a memory unit 720. The memory unit 720 stores the monitoring information 590.

[0029] The functions of the watching management unit 710 are realized by software. The storage unit 720 is provided in the memory 921. Alternatively, the storage unit 720 may be provided in the auxiliary storage device 922. Moreover, the storage unit 720 may be provided separately in the memory 921 and the auxiliary storage device 922.

[0030] The ground equipment 701 transmits and receives monitoring information 590 to and from the monitoring satellite 521 via the infrastructure satellite 511. The monitoring management unit 710 uses the monitoring information 590 transmitted and received from the monitoring satellite 521 to realize a function of dealing with the risk of failure or loss of the critical infrastructure 51. For example, the monitoring management unit 710 realizes a function of warning of danger, preventing danger, or avoiding danger in the critical infrastructure 51.

[0031] The processor 910 is a device that executes a monitoring management program. The monitoring management program is a program that realizes the functions of each component of the ground equipment 701 and the satellite monitoring system 500.

[0032] The processor 910 is an integrated circuit (IC) that performs arithmetic processing. Specific examples of the processor 910 include a CPU, a digital signal processor (DSP), and a graphics processing unit (GPU).

[0033] The memory 921 is a storage device that temporarily stores data. Specific examples of the memory 921 include a static random access memory (SRAM) and a dynamic random access memory (DRAM). The auxiliary storage device 922 is a storage device that stores data. A specific example of the auxiliary storage device 922 is a HDD. The auxiliary storage device 922 may also be a portable storage medium such as an SD (registered trademark) memory card, CF, NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, or a DVD. Note that HDD is an abbreviation for Hard Disk Drive. SD (registered trademark) is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash (registered trademark). DVD is an abbreviation for Digital Versatile Disk.

[0034] The input interface 930 is a port connected to an input device such as a mouse, a keyboard, or a touch panel. Specifically, the input interface 930 is a Universal Serial Bus (USB) terminal. The input interface 930 may be a port connected to a Local Area Network (LAN). The output interface 940 is a port to which a cable of a display device 941 such as a display is connected. Specifically, the output interface 940 is a USB terminal or an HDMI (registered trademark) (High Definition Multimedia Interface) terminal. Specifically, the display is an LCD (Liquid Crystal Display).

[0035] The communication device 950 includes a receiver and a transmitter, and is specifically a communication chip or a network interface card (NIC).

[0036] The watching management program is read into the processor 910 and executed by the processor 910. The memory 921 stores not only the watching management program but also an OS (Operating System). The processor 910 executes the watching management program while executing the OS. The watching management program and the OS may be stored in an auxiliary storage device. The watching management program and the OS stored in the auxiliary storage device are loaded into the memory 921 and executed by the processor 910. Note that a part or all of the watching management program may be incorporated into the OS.

[0037] The ground equipment 701 may include multiple processors that replace the processor 910. These multiple processors share the execution of the monitoring management program. Each processor is a device that executes the monitoring management program, just like the processor 910.

[0038] Data, information, signal values ​​and variable values ​​used, processed or output by the monitoring management program are stored in memory 921, auxiliary storage device 922, or a register or cache memory within processor 910.

[0039] The "unit" in the monitoring management unit 710 may be read as a "process," a "procedure," or a "step." Also, the "process" in the monitoring management process may be read as a "program," a "program product," or a "computer-readable storage medium on which a program is recorded." The monitoring management program causes a computer to execute each process, procedure, or step of the monitoring management unit, where the "unit" is replaced with a "process," "procedure," or "step." The monitoring management method is a method performed by the ground equipment 701 executing the monitoring management program. The monitoring management program may be provided by being stored in a computer-readable recording medium or storage medium. The monitoring management program may also be provided as a program product.

[0040] The processor may be replaced by an electronic circuit. Each of the processor and the electronic circuit is also called a processing circuit. In other words, the functions of each device of the satellite monitoring system 500 are realized by the processing circuitry.

[0041] FIG. 3 shows an example of the configuration of a satellite 30, which is an example of a space object according to this embodiment. Satellite 30 comprises a satellite control device 310, a communication device 32, a propulsion device 33, an attitude control device 34, and a power supply device 35. Satellite 30 also comprises other components that realize various functions, but Fig. 3 will explain only satellite control device 310, communication device 32, propulsion device 33, attitude control device 34, and power supply device 35. Satellite 30 is an example of a space object.

[0042] The satellite control device 310 is a computer that controls the propulsion device 33 and the attitude control device 34, and includes a processing circuit. Specifically, the satellite control device 310 controls the propulsion device 33 and the attitude control device 34 in accordance with various commands transmitted from ground devices. The satellite communication device 32 is a device that communicates with ground facilities or ground devices. Specifically, the communication device 32 transmits various data related to the satellite to the ground devices. The communication device 32 also receives various commands transmitted from the ground devices. The propulsion device 33 is a device that provides thrust to the satellite 30 and changes the speed of the satellite 30. Specifically, the propulsion device 33 is an apogee kick motor, a chemical propulsion device, or an electric propulsion device. The apogee kick motor (AKM) is an upper stage propulsion device used to put an artificial satellite into orbit, and is also called an apogee motor (when a solid rocket motor is used) or an apogee engine (when a liquid engine is used). Chemical propulsion systems are thrusters that use monopropellant or bipropellant fuels. Electric propulsion systems are ion engines or Hall thrusters. An apogee kick motor is a device used for orbital transfer, and can be a type of chemical propulsion system. The attitude control device 34 is a device for controlling attitude elements such as the attitude of the satellite 30, the angular velocity of the satellite 30, and the line of sight (Line Of Sight). The attitude control device 34 changes each attitude element to a desired direction. Alternatively, the attitude control device 34 maintains each attitude element in a desired direction. The attitude control device 34 includes an attitude sensor, an actuator, and a controller. The attitude sensor is a device such as a gyroscope, an earth sensor, a sun sensor, a star tracker, a thruster, and a magnetic sensor. The actuator is a device such as an attitude control thruster, a momentum wheel, a reaction wheel, and a control moment gyro. The controller controls the actuator according to the measurement data of the attitude sensor or various commands from the ground device. The power supply unit 35 includes devices such as solar cells, batteries, and a power control device, and supplies power to each device installed on the satellite 30.

[0043] The processing circuitry provided in the satellite control device 310 will now be described. The processing circuitry may be dedicated hardware or may be a processor that executes a program stored in a memory. In the processing circuit, some functions may be realized by dedicated hardware and the remaining functions may be realized by software or firmware, i.e., the processing circuit may be realized by hardware, software, firmware, or a combination thereof. The dedicated hardware may specifically be a single circuit, a complex circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination of these. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array.

[0044] FIG. 4 is a diagram showing an example of the configuration of a communication satellite 401 according to this embodiment. FIG. 5 is a diagram showing an example of the configuration of the observation satellite 404 according to this embodiment. FIG. 6 is a diagram showing another example of the configuration of the observation satellite 404 according to this embodiment. In addition, in FIG. 3 to FIG. 6, components with the same names have similar functions, and the description thereof may be omitted.

[0045] The configuration of the communication satellite 401 will be described with reference to FIG. The communications satellite 401 includes a communications device 121, a propulsion device 122, a power supply device 123, and a camera 124. For example, the camera 124 is a wide-angle camera that points in the same direction as the direction of the first directional antenna 121E or the second directional antenna 121W.

[0046] The communication satellite 401 allows visual observation of observation satellites and other space objects flying in geostationary orbit or in orbits close to geostationary orbit, making it possible to visually confirm that the environment around the communication satellite 401 is free of obstacles that could cause interference and noise in communications. Other space objects are space objects other than the space objects observed by the observation satellites.

[0047] By arranging the camera 124 so that the line of sight vector is the direction from the communication satellite 401 to the earth, it is possible to visually capture the observation satellite 404 and other space objects flying in geostationary orbit or in orbits close to the geostationary orbit. Furthermore, it is possible to estimate the positions of other space objects in orbit. Therefore, it is possible to visually confirm that the surroundings of the communication satellite 401 are in an environment free of communication interference and noise.

[0048] The configuration of the observation satellite 404 will be described with reference to FIG. The observation satellite 404 includes an observation device 111 , a satellite control device 112 , a communication device 113 , a propulsion device 114 , an attitude control device 115 , a power supply device 116 , and a camera 117 . The observation equipment 111 is a device for observing a space object. The observation equipment 111 is also called a monitoring device. The camera 117 is, for example, a wide-angle camera directed toward the communications satellite 401 .

[0049] The camera 117 can visually capture the communication satellite 401 and other space objects flying in geostationary orbit or in orbits close to the geostationary orbit, making it possible to visually confirm that the surroundings of the observation satellite 404 are in an environment free of interference and noise due to communications.

[0050] By arranging the camera 117 so that the direction from the observation satellite 404 to the communication satellite 401 is the line of sight vector, it is possible to visually capture the communication satellite 401 and other space objects flying in geostationary orbit or in orbits close to the geostationary orbit. Furthermore, it is possible to estimate the positions of other space objects on orbit. Therefore, it is possible to visually confirm that the surroundings of the observation satellite 404 are in an environment free of interference and noise due to communication.

[0051] Another example of the configuration of the observation satellite 404 will be described with reference to FIG. The observation satellite 404 includes an observation device 201 , a satellite control device 202 , a communication device 203 , a propulsion device 204 , an attitude control device 205 , and a power supply device 206 .

[0052] The observation device 201 is a device for observing a space object. The observation device 201 is a device that detects space objects using an optical system. The observation device 201 photographs space objects flying at an altitude different from the orbital altitude of an observation satellite using an optical system. Specifically, the observation device 201 is a visible optical sensor. The observation device 201 generates observation data. The observation data is data obtained by observation performed by the observation device 201. For example, the observation data corresponds to data representing an image showing a space object.

[0053] The satellite control device 202 is a computer that controls the observation satellite 404 . The satellite control device 202 controls the observation device 201, the propulsion device 204, and the attitude control device 205 according to a predetermined procedure or in accordance with various commands transmitted from ground facilities.

[0054] The communication device 203 is a device that communicates with ground facilities and is also called a satellite communication device. The communication device 203 transmits, for example, observation data to ground facilities, and also receives, for example, various commands transmitted from ground facilities.

[0055] ***Description of the configuration and operation of the satellite monitoring system 500*** In this embodiment, the configuration and operation of the satellite monitoring system 500 in the second satellite group 602 shown in FIG. 1 will be mainly described.

[0056] <Overall configuration example of satellite monitoring system 500> In this embodiment, the critical infrastructure 51 is a social infrastructure in outer space. The critical infrastructure 51 is made up of an infrastructure satellite group 510 made up of infrastructure satellites 511 flying in a low earth orbit (LEO) at an orbital altitude of 500 km or more and 2000 km or less. The monitoring satellite group 52 is made up of monitoring satellites 521 that fly at an orbital altitude of 2000 km or less, monitor the infrastructure satellite group 510, and perform on-orbit services. The infrastructure ground facility 54 is an example of ground facility that is installed on the ground and transmits and receives information to and from each infrastructure satellite 511 of the infrastructure satellite group 510 . The monitoring center 53 is an example of a ground facility that is installed on the ground and transmits and receives information to and from the monitoring satellite 521 .

[0057] As shown in FIG. 1, infrastructure satellite constellation 510 includes communications satellite constellation 44 consisting of communications satellite 401 .

[0058] The communications satellites 44 fly in approximately uniformly spaced orbits having an orbital altitude and orbital inclination that result in a sun-synchronous orbit that rotates an integer number of times per day. A communication satellite 401 communicates with communication satellites flying in front and behind it. The communications satellite group 44 includes a first satellite 61 that communicates with ground facilities such as infrastructure ground facilities 54, a second satellite 62 that communicates with a monitoring satellite 521b, and a third satellite 63 that only communicates with communications satellites flying in front of and behind it. The monitoring satellite 521b and the monitoring center 53 exchange information with each other via the group of communication satellites 44.

[0059] FIG. 7 is a diagram showing an example of the configuration of a satellite monitoring system 500 according to this embodiment. 7, a monitoring satellite 521b that plays the role of an ear communicates with a communication satellite 401 that is an infrastructure satellite 511 and also a monitoring satellite that plays the role of a mouth. The communication satellite 401 that communicates with the monitoring satellite 521b is an example of the second satellite 62. Here, the monitoring satellite 521b that plays the role of an ear may be the monitoring satellite 521a that plays the role of an eye, or the monitoring satellite 521c that plays the role of a hand. The monitoring satellite 521b acting as an ear and the communication satellite 401 which is an example of the second satellite 62 are provided with a second communication device 42 which communicates between infrastructure satellites.

[0060] The communication satellite 401, which is an example of the first satellite 61, includes a first communication device 41 that communicates with ground facilities. The communication satellite 401, which is an example of the first satellite 61, also includes a second communication device 42 that communicates with other infrastructure satellites.

[0061] The communications satellite 401, which is an example of the third satellite 63 that only communicates with communications satellites flying before and after it, includes a second communications device 42 that communicates with other infrastructure satellites.

[0062] In the satellite constellation flying in LEO, when the infrastructure satellite 511 flies on the other side of the Earth, even if an emergency response occurs, it may not be possible to secure a communication environment with the monitoring center 53. However, according to the satellite monitoring system 500 of this embodiment, an environment in which multiple communication satellites communicate with each other is provided, and monitoring information can be sent and received from the other side of the earth via multiple communication satellites. Therefore, there is an effect that monitoring information can be sent and received from the monitoring center anytime and anywhere. This has the effect of enabling the infrastructure satellite 511 to take immediate action to avoid danger if a dangerous space object such as debris approaches.

[0063] <Configuration Example 1 of Communications Satellite Group 44> Each communication satellite 401 of the communication satellite group 44 flies in a sun-synchronous orbit at an altitude of about 1,666 km, making 12 revolutions per day. The communication satellite group 44 is made up of five or more communication satellites 401.

[0064] The orbital altitude is approximately 1,666 km, with 12 orbits per day, and if the orbital inclination is set to 77° (180°-103°), it will be a sun-synchronous orbit. When five satellites fly in this orbit in equal phase, the radius of the inscribed circle of the pentagon formed is greater than the radius of the Earth, ensuring communication line of sight between the satellites. Assuming that the altitude at which the effects of the atmosphere can be ignored is 300 km, six or more satellites would have the effect of ensuring communication links at altitudes of 585 km or more above the Earth's surface. In addition, since the satellite returns to the same latitude at the same time every two hours, information can be exchanged at the ground equipment at a fixed time every two hours.

[0065] <Configuration Example 2 of Communications Satellite Group 44> Each communication satellite 401 of the communication satellite group 44 flies in a sun-synchronous orbit at an altitude of about 1248 km, making 13 revolutions per day. The communication satellite group 44 is made up of six or more communication satellites.

[0066] The orbital altitude is approximately 1,248 km, with 13 orbits per day, and if the orbital inclination is set to 79° (180° - 101°), it will be a sun-synchronous orbit. When six satellites fly in this orbit in equal phase, the radius of the inscribed circle of the hexagon formed is larger than the radius of the Earth, ensuring communication line of sight between the satellites. Assuming that the altitude at which the effects of the atmosphere can be ignored is 300 km, seven or more satellites would have the effect of ensuring communication links at an altitude of 491 km or more above the Earth's surface. Since it returns to the same latitude at the same time every day, every 111 minutes, the advantage is that information can be exchanged at the ground equipment at a fixed time every day, every 111 minutes.

[0067] <Configuration Example 3 of Communications Satellite Group 44> Each communication satellite 401 of the communication satellite group 44 flies in a sun-synchronous orbit at an altitude of about 881 km, making 14 revolutions per day. The communication satellite group 44 is made up of seven or more communication satellites.

[0068] FIG. 8 is a diagram showing a third configuration example of a communications satellite group 44 according to the present embodiment. The orbital altitude is approximately 881 km, with 14 orbits per day, and if the orbital inclination is set to 81° (180°-99°), it will be a sun-synchronous orbit. By setting the orbital parameters to be sun-synchronous at an orbital altitude of 881 km, an orbit with 14 orbits per day can be achieved. When seven satellites fly in this orbit in equal phase, the radius of the inscribed circle of the hexagon formed is larger than the radius of the Earth, ensuring communication line of sight between the satellites. Assuming that the altitude at which the effects of the atmosphere can be ignored is 300 km, eight or more satellites would have the effect of ensuring communication links at an altitude of 327 km or more above the Earth's surface.

[0069] Since it returns to the same latitude at the same time every day, every 103 minutes, the advantage is that information can be exchanged at the ground equipment at a fixed time every day, every 103 minutes. Note that an inclination of 77° is the same as 103° depending on the definition, an inclination of 79° is the same as 101° depending on the definition, and an inclination of 81° is the same as 99° depending on the definition.

[0070] <Configuration Example 4 of Communications Satellite Group 44> The communications satellite group 44 is in a sun-synchronous orbit and is composed of satellites in two orbital planes, LST9:00 and LST15:00. LST is an abbreviation for Local Sun Time.

[0071] FIG. 9 is a diagram showing a fourth configuration example of a communications satellite group 44 according to the present embodiment. Earth observation satellites often use sun-synchronous orbits. Optical satellites often use the time periods around LST10:30 and LST13:30 when sunlight conditions are good. Radar satellites often use the time periods LST06:00 and LST18:00 when solar power generation is favorable. When the orbital altitude of the communication satellite is 881 km, the inscribed circle of a regular octagon is 6727 km, so that it is possible to secure a communication link with any LST monitoring satellite. Note that the monitoring satellite may be a user satellite that uses the communication satellite group 44 as a communication link. Therefore, if a communications satellite is deployed in two orbital planes at LST09:00 and LST15:00, it will be possible to communicate with all of the satellites commonly used for Earth observation.

[0072] <Communication method of the 44 communications satellites> FIG. 10 is a diagram showing a communication system of a group of communication satellites 44 according to this embodiment. The communication satellite 401 and the monitoring satellite 521 each include a two-way communication terminal 65 equipped with a transmission / reception switching device 64 that realizes reception and transmission by switching between a reception function and a transmission function. The ground equipment 701, which is the monitoring center 53, operates the transmission / reception switching device 64 so that the ratio of the reception time to the transmission time of the monitoring satellite 521 becomes α to β based on the data amount α of the command to be transmitted to the monitoring satellite 521 and the data amount β of the monitoring data and telemetry received from the monitoring satellite 521. Specifically, the ground equipment 701 operates the transmission / reception switching device 64 so that the ratio of the reception operation time during which the reception function operates to the transmission operation time during which the transmission function operates in the two-way communication terminal 65 becomes α to β based on the data amount α of the command to be transmitted to the monitoring satellite 521 and the data amount β of the monitoring report data received from the monitoring satellite 521. The monitoring satellite 521 and the ground equipment 701 exchange information with each other via the communication satellite 401 .

[0073] In this embodiment, a configuration example in which commands and monitoring report data are exchanged between the monitoring satellite and the monitoring center has been described. However, the monitoring satellite may be another user satellite that uses the communication satellite group 44 as a communication line.

[0074] Embodiment 2 In this embodiment, the following mainly describes the points that are added to or different from embodiment 1. Note that the same components as those in embodiment 1 are given the same reference numerals, and the description thereof may be omitted.

[0075] In the first embodiment, a configuration has been mainly described in which the watching satellite 521 and the watching center 53 transmit and receive information via the communication satellites 44 included in the infrastructure satellites 510. In this embodiment, a satellite information transmission system 501 in which a user satellite 531 and a ground facility 702 exchange information with each other via a group of communications satellites 44 included in a group of infrastructure satellites 510 will be described.

[0076] FIG. 11 is a diagram showing an example of the configuration of a satellite information transmission system 501 according to this embodiment. FIG. 12 is a diagram showing an example of the overall configuration of a satellite information transmission system 501 according to this embodiment. The basic configuration of the satellite information transmission system 501 is the same as that of the satellite monitoring system 500 described in embodiment 1. The satellite information transmission system 501 is the same as that of the satellite monitoring system 500 described in embodiment 1, except that the monitoring satellite 521 is replaced with a user satellite 531 and the monitoring center 53 is replaced with a ground facility 702.

[0077] In Figures 11 and 12, the first satellite 61 that communicates with the ground equipment 702 is represented as "first," the second satellite 62 that communicates with the user satellite 531 is represented as "second," and the third satellite 63 that only communicates with the communication satellites flying in front and behind it is represented as "third."

[0078] The satellite information transmission system 501 includes a critical infrastructure 51 that is made up of a group of infrastructure satellites 510 that fly in LEO, and ground facilities 702 that exchange information with each of the infrastructure satellites of the group of infrastructure satellites 510. The infrastructure satellite group 510 is made up of the communications satellite group 44 and a user satellite group 530 made up of user satellites 531 that use the communications satellite group 44 as a communication link.

[0079] 11 and 12, the group of communication satellites 44 fly in an approximately uniform arrangement in orbits having an orbital altitude and orbital inclination that result in a sun-synchronous orbit that rotates an integer number of times per day. A communication satellite 401 communicates with the communication satellites flying in front of and behind it. The communications satellite group 44 includes a first satellite 61 that communicates with the ground facility 702, a second satellite 62 that communicates with the user satellite 531, and a third satellite 63 that only communicates with the communications satellites flying in front and behind it. The user satellite 531 and the ground facility 702 exchange information via the communications satellite group 44.

[0080] <Configuration Example 1 to Configuration Example 4 of Communications Satellite Group 44> Also, as for the configuration example of the communications satellite group 44 according to the present embodiment, it is possible to apply configurations similar to configuration example 1 to configuration example 4 of the communications satellite group 44 described in the embodiment.

[0081] <Communication method of the 44 communications satellites> The communication system of the communication satellite group 44 according to this embodiment may be the same as the communication system of the communication satellite group 44 described in the embodiment.

[0082] FIG. 13 is a diagram showing a communication system of a group of communication satellites 44 according to this embodiment. The communications satellite 401 and the user satellite 531 are each equipped with a two-way communication terminal 65 equipped with a transmit / receive switch 64. The ground facility 702 operates the transmit / receive switch 64 based on the data volume α of the command to be transmitted to the user satellite 531 and the data volume β of the user information data received from the user satellite 531 so that the ratio of the reception time to the transmission time of the user satellite 531 becomes α to β. The user satellite 531 and the ground facility 702 exchange information via each communication device of the communication satellite group 44 .

[0083] Embodiment 3 In this embodiment, the following mainly describes additions or differences from embodiments 1 and 2. Note that the same components as those in embodiments 1 and 2 are given the same reference numerals, and the description thereof may be omitted.

[0084] <Ground facilities> In this embodiment, a description will be given of the ground equipment used in the satellite monitoring system 500 or the satellite information transmission system 501 described in the first and second embodiments. Examples of the ground equipment include the ground equipment 701 owned by the monitoring center 53, the ground equipment 54 for each infrastructure, or the ground equipment 702 that transmits and receives information to and from the user satellite 531.

[0085] FIG. 14 is a diagram illustrating the ground equipment according to the present embodiment. The ground equipment used in the satellite monitoring system 500 or satellite information transmission system 501 described in the first and second embodiments is installed at a latitude of 60° or higher, and communicates with the first satellite 61, “First”, every orbit.

[0086] The Earth's rotation period and orbital period are different. For this reason, when a communications satellite flying in an orbit at 09:00 LST communicates with ground equipment, for example, with ground equipment installed near the equator, communication may only be possible twice, around 09:00 AM and around 09:00 PM. In contrast, with ground equipment installed on high latitude ground, even though the Earth's rotation period and orbital period are different, communication with ground equipment is possible every time the communications satellite orbits the Earth.

[0087] <Example 1 of a communications satellite> Next, a first example of the communication satellite 401 used in the satellite monitoring system 500 or the satellite information transmission system 501 described in the first and second embodiments will be described.

[0088] FIG. 15 is a diagram for explaining example 1 of a communication satellite according to the present embodiment. In the communication satellite example 1, the communication satellite 401 includes a first communication device 41 that communicates with ground facilities and three second communication devices 42 that communicate with each other among the infrastructure satellites. In the communication satellite example 1, the communication satellite 401 simultaneously communicates with a communication satellite flying in the same orbital plane and a monitoring satellite or a user satellite.

[0089] If a satellite is equipped with one set of first communication devices for communicating with ground facilities and three sets of second communication devices for communicating between infrastructure satellites, it can simultaneously communicate with communication satellites flying in the same orbital plane, as well as monitoring satellites or user satellites. Furthermore, the communications satellite according to the first example of the communications satellite according to the present embodiment has the advantage that information communicated with the user satellite can be transmitted to the ground equipment in real time. Therefore, when critical infrastructure is under construction, even in a situation where the number of satellites flying in the same orbital plane is small, it is possible to transmit and receive information between user satellites and ground facilities. Furthermore, communication terminals can be standardized, which has the effect of reducing total costs.

[0090] <Communication satellite example 2> Next, a second example of a communication satellite used in the satellite monitoring system 500 or the satellite information transmission system 501 described in the first and second embodiments will be described.

[0091] FIG. 16 is a diagram showing an example of a satellite information transmission system 501 according to this embodiment. In communication satellite example 2, the communication satellite 401 includes a first communication device 41 that communicates with ground equipment, a second communication device 42 that communicates between infrastructure satellites, and a third communication device 43 that communicates with a monitoring satellite 521 or a user satellite 531.

[0092] FIG. 17 is a diagram for explaining a second example of a communications satellite according to the present embodiment. In the communication satellite example 2, the communication satellite 401 is equipped with one first communication device for communicating with ground facilities, two second communication devices for communicating with infrastructure satellites flying around the orbital plane, and one third communication device for communicating with a monitoring satellite or a user satellite. This has the effect of enabling information communicated with the user satellite to be transmitted to the ground facilities in real time. Therefore, when critical infrastructure is under construction, even in a situation where the number of satellites flying in the same orbital plane is small, it is possible to transmit and receive information between user satellites and ground facilities. Furthermore, by using dedicated terminals for the monitoring satellite or user satellite, communication is possible even with small terminals having small apertures, which has the effect of enabling the monitoring satellite or user satellite to be realized with a small satellite.

[0093] Embodiment 4 In this embodiment, the following will be mainly described with respect to the points added or different from the first to third embodiments. Note that the same reference numerals are used to designate the same configurations as those in the first to third embodiments, and the description thereof may be omitted.

[0094] In this embodiment, a monitoring system 502 is described in which satellites of a first satellite constellation 810 that monitor the Earth, flying bodies, and space objects exchange satellite information with ground equipment via satellites of a second satellite constellation 820.

[0095] <Example of overall configuration of monitoring system 502> FIG. 18 is a diagram showing an example of the configuration of a monitoring system 502 according to this embodiment. In the monitoring system 502, a constituent satellite 811 of a first satellite constellation 810 that monitors the Earth, flying bodies, and space objects exchanges satellite information with ground equipment via a constituent satellite 812 of a second satellite constellation 820.

[0096] A first satellite constellation 810 is a group of three or more satellites that work together to monitor the Earth, airborne vehicles, and space objects. The ground equipment exchanges information with the constituent satellites of the first satellite constellation 810. The second satellite constellation 820 flies in a sun-synchronous orbit at an altitude of 800 km or more, approximately evenly spaced, and relays satellite information in cooperation with a group of six or more communication satellites that communicate with satellites flying in front of and behind the same orbital plane. In other words, the constituent satellites of the second satellite constellation 820 are a group of six or more communication satellites.

[0097] The constituent satellites of the first satellite constellation 810 exchange information with ground facilities via the second satellite constellation 820 .

[0098] In recent years, the emergence of flying objects that glide at supersonic speeds has raised hopes for satellite launch and flight path tracking, but it can be difficult to establish a constant communication environment in LEO constellations.

[0099] There is also a technology to send and receive information via data relay satellites in geostationary orbit. However, as the number of satellites in orbit increases and the frequency of use of data relay satellites increases, communication lines may not be available in emergencies. In addition, time delays may occur because information is transmitted from LEO satellites to ground facilities via geostationary orbit.

[0100] In the monitoring system 502 according to this embodiment, information can be constantly exchanged between the first satellite constellation and ground facilities via a group of communication satellites configured in low-altitude sun-synchronous orbits. Another advantage is that information can be exchanged in a shorter time than via a data relay satellite in geostationary orbit.

[0101] Furthermore, by increasing the number of satellites in the second satellite constellation, it is possible to increase the number of satellites in the first satellite constellation with which data can be exchanged simultaneously, which has the effect of making it possible to exchange monitoring data for a large number of monitored objects at the same time. In addition, by increasing the number of satellites in the second satellite constellation, it is possible to increase the number of ground facilities that can simultaneously receive and transmit data, which has the effect of enabling response actions to multiple monitoring targets at the same time.

[0102] In addition, when using a sun-synchronous orbit satellite to monitor the Earth, flying objects, or space objects using a visible high-resolution optical monitoring device, there is a problem that the time during which information can be sent and received by ground equipment installed at a specific longitude is limited. A similar problem exists even when using a geostationary data relay satellite. The monitoring system 502 according to this embodiment has the effect of being able to be used for emergency responses in the event of a disaster, etc., by realizing a constant communication environment via a group of low-orbit communication satellites.

[0103] Geostationary orbits are generally used for satellites above the equator, but one issue is that high-resolution monitoring is difficult with geostationary satellites flying at an altitude of 36,000 km. For this reason, if an orbit that orbits the equator multiple times a day is adopted, high-resolution monitoring becomes possible. However, even in this case, there is an issue that constant communication is not possible with only ground equipment installed at a specific longitude. Therefore, this has the effect of realizing a group of satellites orbiting above the equator that can communicate at all times.

[0104] <Example 1 of the first satellite constellation 810> Example 1 of the first satellite constellation 810 is a satellite constellation that orbits an inclined circular orbit at an altitude of 1000 km to 6000 km multiple times per day. The normals of the multiple orbital planes formed by the multiple constituent satellites included in the first satellite constellation 810 are offset from each other by equal angles in the azimuth direction, and the flight positions of the orbital planes are synchronously controlled.

[0105] FIG. 19 shows a configuration example of Example 1 of the first satellite constellation 810 according to this embodiment. The number of times each satellite orbits the Earth per day is defined as "N." A first satellite constellation 810 comprises N constituent satellites. Each satellite moves in an inclined circular orbit, orbiting the Earth N times per day. The plane in which the satellites move is called the orbital plane. The N orbital planes formed by the N constituent satellites have their normals shifted by 360 degrees over N in the azimuth direction. In other words, the relative angles of the azimuth components are shifted by 360 degrees over N. The azimuth direction corresponds to the direction of travel of the constituent satellites. In other words, the azimuth direction corresponds to the longitude direction and the east-west direction.

[0106] Specifically, the first satellite constellation 810 includes eight constituent satellites (AH) forming eight orbital planes. Each component satellite orbits the Earth eight times per day. The normals to the eight orbital planes are offset by 45 degrees relative to each other in azimuth.

[0107] The timing of the passage of the N constituent satellites (A to H) over the northernmost point of each orbital plane is synchronized, that is, the N constituent satellites (A to H) pass over the northernmost point of each orbital plane at the same time.

[0108] <Example 2 of the first satellite constellation 810> Example 2 of the first satellite constellation 810 flies in a sun-synchronous non-frozen elliptical orbit with a perigee altitude of 300 km or more and an apogee altitude of 6000 km or less. The orbital planes formed by the multiple constituent satellites included in the first satellite constellation 810 are offset by equal angles in the azimuth direction components of the major axes of the orbital planes.

[0109] FIG. 20 shows a configuration example of Example 2 of the first satellite constellation 810 according to this embodiment. FIG. 20 shows example 2 of the first satellite constellation 810 as viewed normal to the orbital plane. The first satellite constellation 810 includes a plurality of constituent satellites (A to C). Each constituent satellite revolves in a sun-synchronous elliptical orbit. Each elliptical orbit has a high eccentricity and an orbital inclination. That is, the orbit of each constituent satellite is a sun-synchronous orbit, an inclined orbit, and an elliptical orbit. Also, the elliptical orbit of each constituent satellite is a non-frozen orbit. That is, the elliptical orbit of each constituent satellite is not a frozen orbit, and the major axis of each elliptical orbit rotates around the Earth in the orbital plane over time.

[0110] The three satellites (A, B, C) monitor the region of interest on Earth from either perigee, apogee or midpoint, with the midpoint being a point between perigee and apogee. At perigee, short but high resolution surveillance can be performed. At apogee, lower resolution but long term monitoring is possible.

[0111] The major axis of each of the three elliptical orbits is inclined at equal intervals of approximately 120° to the circumference of the orbital plane. The azimuth direction corresponds to the longitude direction, i.e., the east-west direction. The major axis of each elliptical orbit rotates relative to the Sun 102, but the relative relationships between the three elliptical orbits are maintained.

[0112] <Example 3 of the first satellite constellation 810> Example 3 of the first satellite constellation 810 orbits the equator multiple times per day, and the flight positions are synchronously controlled by shifting the azimuth direction components by equal angles. In Example 1 of the first satellite constellation 810 of FIG. 19, each constituent satellite moves in an inclined circular orbit and orbits the Earth N times per day. On the other hand, in example 3 of the first satellite constellation 810, each constituent satellite travels in an equatorial orbit, orbiting the Earth N times per day. Each constituent satellite moves in an inclined circular orbit, orbiting the Earth N times per day. The orbital planes in which each constituent satellite moves are offset by equal angles in the azimuth direction so that their flight positions are synchronously controlled.

[0113] <Example 4 of the second satellite constellation> FIG. 21 is a diagram showing a configuration example of Example 4 of the second satellite constellation 820 according to the present embodiment. Example 4 of the second satellite constellation 820 includes a first satellite 61 that communicates with ground facilities, a second satellite 62 that communicates with the constituent satellites of the first satellite constellation 810, and a third satellite 63 that only communicates with satellites flying in front of and behind it.

[0114] <Example 5 of the second satellite constellation> Example 5 of the second satellite constellation 820 is a sun-synchronous orbit, and is a group of six or more communication satellites flying in the orbital planes of LST09:00 and LST15:00 that work together to relay satellite information.

[0115] Earth observation satellites often use sun-synchronous orbits. Optical satellites often use the time periods around LST10:30 and LST13:30 when sunlight conditions are good. Radar satellites often use the time periods LST06:00 and LST18:00 when solar power generation is favorable. When the orbital altitude of the communication satellite is 881 km, the inscribed circle of a regular octagon is 6727 km, so that it is possible to secure a communication link with any LST monitoring satellite. Note that the monitoring satellite may be a user satellite that uses the communication satellite group 44 as a communication link. Therefore, as shown in Figure 18, if the constituent satellites of the second satellite constellation 820 are deployed in two orbital planes at LST09:00 and LST15:00, it will be possible to communicate with all of the satellite groups frequently used for Earth observation.

[0116] ***Other configurations*** The ground equipment of the monitoring system 502 according to this embodiment may be a moving body. For example, when detecting the launch of a flying object gliding at supersonic speed, it is reasonable to transmit the information to a moving object such as an aircraft, UAV (unmanned aerial vehicle), ship, or vehicle that can directly respond in order to carry out a response action in a short time.

[0117] Embodiment 5. In this embodiment, the following mainly describes additions or differences from embodiments 1 to 4. Note that the same components as those in embodiments 1 to 4 are given the same reference numerals, and descriptions thereof may be omitted. In this embodiment, the communication method of the satellite information transmission system 501 will be mainly described.

[0118] <Communication method example 1 of the satellite information transmission system 501> FIG. 22 is a diagram showing an example of the configuration of a satellite information transmission system 501 according to this embodiment. FIG. 23 is a diagram showing an example of the overall configuration of a satellite information transmission system 501 according to this embodiment. Satellite information transmission system 501 according to this embodiment relays satellite information between ground equipment 702 and user satellite 531 that constitutes a constellation of user satellites orbiting the earth. The satellite information transmission system 501 includes a group of communication satellites 44 consisting of six or more communication satellites that orbit in a sun-synchronous orbit in a low earth orbit (LEO) at an orbital altitude of 500 km or more and 2000 km or less, approximately evenly spaced, and communicate with communication satellites flying in front of and behind them in the same orbital plane. A communication satellite 401 communicates with communication satellites flying in front and behind it.

[0119] In communication method example 1 of satellite information transmission system 501, communication satellite group 44 includes a first satellite 61 that performs optical communication with ground facility 702, a second satellite 62 that performs optical communication with user satellite 531, and a third satellite 63 that performs communication only with communication satellites flying in front and behind. In communication satellite group 44, radio wave communication is performed between the communication satellites flying in front and behind. Optical communication is performed by an optical communication terminal 544. Radio communication is performed by a radio communication terminal 542.

[0120] Optical communications has the advantage of being able to transmit large volumes of data. However, because it is necessary to align the optical axes between satellites with high precision, both user satellites and communication satellites require high-precision two-axis pointing control. Since the relative positions of the ground equipment and the communications satellites fluctuate greatly, the pointing direction, which changes from moment to moment, must be controlled with high precision in real time. In addition, when the relative positional relationship between the user satellite and the communications satellite changes significantly, the pointing direction, which also changes from moment to moment, must be controlled with high accuracy in real time. When the relative position fluctuation is large, the communication time is also limited, so large-capacity communication is required.

[0121] For a single satellite to simultaneously realize optical communications between the preceding and succeeding communications satellites, the user satellite, and ground facilities, it would need to simultaneously align the optical axis with different targets with high precision, which is technically difficult and poses a high risk of communication interruption. In radio communication, to achieve high-speed, large-volume data transmission over long distances, it is necessary to align the central axis of the radio wave's main beam with high precision, as in the case of optical communication. However, in close-range communication, low-speed communication, or communication with a limited amount of data, communication without high-precision axis alignment is possible using fixed antennas or omnidirectional antennas.

[0122] In the communication between the front and rear of the communication satellite group according to the above-mentioned embodiment, the distance between the satellites is limited and the relative angle fluctuation between the front and rear satellites is small, so that communication can be realized by radio communication using fixed antennas rather than optical communication or high-speed, large-capacity radio communication, which require high-precision directional control. Furthermore, since communication is possible at all times, even low-speed communication can enable large-volume communication over a period of time. If radio wave communication that does not require high-precision pointing control is used between the preceding and succeeding satellites, the number of communication targets requiring high-precision pointing control at the same time is limited to one, whether the first satellite is communicating optically with ground facilities or the third satellite is communicating optically with a user satellite. This has the effect of making pointing control easier and minimizing the risk of communication interruptions.

[0123] <Communication method example 2 of the satellite information transmission system 501> In the communication method example 2 of the satellite information transmission system 501, the radio waves between the communication satellites flying in front and behind are spectrum spread. When satellites flying in the same orbit communicate with each other using radio waves, there is a risk that multiple satellites flying in front or behind the satellite may cause radio interference or erroneous transmission. By using spectrum spreading to recover only the desired satellite signal, radio interference or erroneous transmission can be avoided.

[0124] <Communication method example 3 of the satellite information transmission system 501> In the communication method example 3 of the satellite information transmission system 501, the communication satellite is provided with a two-way communication terminal 65 with a transmission / reception switching function for communicating with communication satellites flying in front and behind. If a communication satellite is equipped with a transmitting terminal for the forward satellite and a receiving terminal for the backward satellite, and all satellites in the same orbit communicate with the satellites before and after it, it will be a satellite information transmission system. However, there is a high risk of communication being cut off during the preparation stage of putting the satellite into orbit, or if a malfunction occurs in orbit. If a two-way communication terminal 65 with a transmission / reception switching function is equipped, it has the effect of making satellite information transmission possible even if all satellites are not in orbit.

[0125] <Communication method example 4 of satellite information transmission system 501> In the communication method example 4 of the satellite information transmission system 501, the communication satellite employs different polarized waves for transmission and reception. Since the relative position and attitude with respect to the preceding and succeeding communications satellites are maintained, the use of different polarizations for transmission and reception has the effect of eliminating the risk of radio interference or erroneous transmission.

[0126] <Communication method example 5 of satellite information transmission system 501> In communication method example 5 of satellite information transmission system 501, communication satellite group 44 includes a fourth satellite that optically communicates with ground facilities and also optically communicates with a user satellite. For urgent satellite information, if one satellite simultaneously transmits and receives information between a user satellite and ground equipment, the delay time can be minimized. The need for high-precision pointing control with two targets at the same time makes the system highly technically difficult and expensive, but compared to the case where communication with the front and rear satellites is also optical, and high-precision pointing control is required with four different targets, it is much easier to put into practical use and has the advantage of being less expensive. In addition, when there is no emergency, the flight positions where a user satellite and ground equipment can communicate simultaneously are limited, so if one satellite is equipped with communication capabilities with both and communicates on a time-sharing basis, the number of targets for high-precision pointing control at the same time can be limited to one.

[0127] <Communication method example 6 of satellite information transmission system 501> FIG. 24 is a diagram showing a sixth example of a communication method of the satellite information transmission system 501 according to the present embodiment. The fourth satellite 644 uses the same optical communication terminal 544 for both optical communication with the ground facility 702 and optical communication with the user satellite 531. The fourth satellite 644 rotates around the satellite flight axis, and performs optical communication with the ground facility 702 and optical communication with the user satellite 531 in a time-division manner.

[0128] When there is no emergency, the flight positions where a user satellite and ground equipment can communicate simultaneously are limited, so if one satellite is equipped with communication capabilities with both and communicates on a time-sharing basis, the number of targets that can be subjected to high-precision pointing control at the same time can be limited to one. Furthermore, standardization of communication terminals between user satellites and ground facilities will have a cost-reduction effect. This is effective when there are a sufficient number of communication satellites in orbit and they do not deviate from the radio field of view even when rotating around their axis of travel.

[0129] ***Other configurations*** The ground equipment 702 according to this embodiment may be a moving body. When urgent satellite information needs to be transmitted from fixed ground facilities to a mobile unit, transmitting the information directly from a communications satellite to the mobile unit can minimize the delay time. This is effective in cases where even a delay of a few seconds can increase risk, such as when issuing instructions on how to respond to an aerial vehicle's launch.

[0130] The group of communication satellites 44 may also include a first satellite 61 that communicates by radio waves with the ground facility 702, a second satellite 62 that communicates by optical waves with the user satellite 531, and a third satellite 63 that only communicates with the communication satellites flying in front and behind. The group of communication satellites 44 communicate by radio waves between the communication satellites flying in front and behind. Optical communication between the communication satellites and the ground facility has a problem that communication is not possible when there are clouds. For this reason, when the ground facility 701 that uses the satellite information transmission system of the communication method example 1 is in an area with a high cloud coverage rate, there is an effect of improving availability by using radio communication.

[0131] Embodiment 6 In this embodiment, the following will be mainly described with respect to additions or differences from the first to fifth embodiments. Note that the same components as those in the first to fifth embodiments are given the same reference numerals, and the description thereof may be omitted. In this embodiment, the configuration of a communication satellite constellation, a satellite constellation, and a satellite information transmission system using satellites flying in sun-synchronous orbits described in the first to fifth embodiments will be mainly described.

[0132] <Configuration of Satellite 80> FIG. 25 is a diagram showing an example of the configuration of an artificial satellite 80 according to this embodiment. The artificial satellite 80 according to this embodiment includes, as an information processing device 81, a computer or a supercomputer equipped with AI (Artificial Intelligence) and at least one of a cloud server or an edge server. The artificial satellite 80 flies in a sun-synchronous orbit at LST06:00 or LST18:00. At this time, the artificial satellite 80 has a solar cell oriented on the side where sunlight is incident, and is provided with a heat dissipation surface of an information processing device 81 on the side opposite to the sunlight incidence. The artificial satellite 80 has a solar cell oriented on the side where sunlight is incident, and is provided with a heat dissipation surface of, for example, a computer or an edge server on the side opposite to the sunlight incidence.

[0133] A sun-synchronous orbit is a type of polar orbit that passes over the polar regions. In a sun-synchronous orbit, the rotational period of the orbital plane around the north-south axis is synchronized with the Earth's orbital period. Therefore, in a sun-synchronous orbit, the angle of incidence of the sun on the orbital plane remains constant throughout the year. In addition, in an orbit at LST06:00 or LST18:00, the normal vector of the orbital plane is directed toward the sun, so even a low-orbit satellite is not in the shadow of the earth and is constantly exposed to sunlight. Strictly speaking, the normal vector is tilted away from the sun due to the tilt of the earth's axis, but the effect is minor.

[0134] The computers and servers that act as the brains of monitoring satellites are becoming increasingly power-hungry with the advent of AI and increased server capacity and speed, and as they generate a lot of heat, heat dissipation measures are becoming a challenge. Sun-synchronous orbits at LST06:00 or LST18:00 are also called Dawndusk orbits. Although Dawndusk orbits are low-earth orbit satellites, they do not enter the Earth's shadow and can generate power from solar cells at all times. Furthermore, Dawndusk orbits have excellent heat dissipation performance through radiative cooling, since the side opposite to the solar incidence is always facing deep space. Therefore, Dawndusk orbits have the effect of securing large amounts of power and dissipating heat from high-heat generating devices. The information processing device 81 is an example of a high heat generating device.

[0135] In addition, with the recent increase in scale and speed of cloud computing, the cloud environment in terrestrial systems also faces the issue of high power consumption and heat exhaust measures for high heat generating devices. Therefore, by regarding the satellite 80 equipped with an edge server as an IOT and performing distributed computing, it is possible to reduce the load on terrestrial systems and contribute to the SDGs. Furthermore, by equipping the satellite 80 with a supercomputer or cloud server and providing centralized computing equipment in space, it will be possible to reduce the load on ground systems and contribute to the achievement of the SDGs. IOT is an abbreviation for Internet of Things. SDGs is an abbreviation for Sustainable Development Goals.

[0136] <Example of the configuration of the communications satellite constellation 801> FIG. 26 is a diagram showing an example of the configuration of a communications satellite constellation 801 according to this embodiment. The communications satellite constellation 801 is a satellite constellation that flies in a sun-synchronous orbit at 06:00 LST or 18:00 LST. The communications satellite constellation 801 includes communications satellites equipped with communication devices with the ground. The communications satellites are an example of the artificial satellites 80. The communication satellite constellation 801 also includes communication devices that allow communication between communication satellites flying in front of and behind the same orbital plane, forming a circular communication network.

[0137] According to the communications satellite constellation 801, since the communications satellite can generate power continuously using fixed solar cells, it has the advantage that the communications satellite can be realized at low cost.

[0138] <Example of the configuration of satellite constellation 802> FIG. 27 is a diagram showing an example of the configuration of a satellite constellation 802 according to this embodiment. In FIG. 27, in a satellite constellation 802, the satellites are equipped with edge servers. Satellite constellation 802 flies in a sun-synchronous orbit at 06:00 LST or 18:00 LST. The satellite constellation 802 includes satellites, which are examples of satellites 80.

[0139] The satellite is equipped with at least one of a computer or supercomputer equipped with a satellite AI, and a cloud server or an edge server as information processing device 81. Also, in the satellite, a solar cell is oriented toward the side where sunlight is incident, and a heat dissipation surface of the information processing device 81 is provided on the side opposite to the sunlight incidence. In the satellite, a solar cell is oriented toward the side where sunlight is incident, and a heat dissipation surface of, for example, a computer or an edge server is provided on the side opposite to the sunlight incidence. The satellite is equipped with a communication device with the ground.

[0140] The satellite constellation 802 is provided with communication devices that allow satellites flying in front of and behind the same orbital plane to communicate with each other, forming a circular communication network. That is, the satellites that make up the satellite constellation 802 are provided with communication devices that allow satellites flying in front of and behind the same orbital plane to communicate with each other, forming a circular communication network.

[0141] The sun-synchronous orbit passes through the polar regions every time. Therefore, the satellite constellation 802 has an advantage that all the satellites can constantly communicate with terrestrial data centers installed in high latitudes via a circular communication network.

[0142] FIG. 28 is a diagram showing another example of the configuration of a satellite constellation 802 according to this embodiment. In FIG. 28, the satellite constellation 802 is composed of a communications satellite, a satellite equipped with a supercomputer, and a satellite equipped with a cloud server. According to the satellite constellation 802 in FIG. 28, the results of analysis and processing performed in orbit can be transmitted to users on the ground, which has the effect of reducing the burden on ground systems.

[0143] <Configuration Example 1 of Satellite Information Transmission System 503> FIG. 29 is a diagram showing a configuration example of Example 1 of a satellite information transmission system 503 according to the present embodiment. FIG. 29 shows the satellite information transmission system 503 as viewed from the direction of the sun.

[0144] The first example of the satellite information transmission system 503 is made up of a group of user satellites, a group of communication satellites, and ground facilities. The user satellite constellation consists of user satellites flying in low earth orbit (LEO) at orbital altitudes between 500 km and 2000 km. The communications constellation consists of multiple communications satellites flying in sun-synchronous orbits at 06:00 LST or 18:00 LST. Each satellite in the communications constellation is an example of a satellite 80 .

[0145] The communications satellite constellation includes a first satellite that communicates with ground facilities and a second satellite that communicates with a user satellite. The communications satellite constellation communicates with communications satellites flying in front of and behind the first satellite. The user satellite and the ground equipment exchange information via a constellation of communication satellites.

[0146] Due to the effect of the Earth's rotation, satellites in sun-synchronous orbit can only communicate with ground equipment during the same time period as the LST in low to mid-latitude regions. On the other hand, if the satellite can be seen from above the polar regions, it can communicate with ground equipment at all times, not limited to the time period of the LST. Therefore, if a circular communication network is formed by communicating with the satellites before and after it, and a satellite passing near the polar regions communicates with ground equipment on its behalf, it will be possible to communicate with ground equipment at all times.

[0147] The user satellites constitute a missile tracking system that is responsible for detecting and tracking the launch of missiles. Information from the user satellites must be transferred quickly in the event of an emergency. According to the example 1 of the satellite information transmission system 503, there is an advantage that satellite information can be rapidly transmitted to ground equipment installed in the high latitudes via a circular communication network. The user satellites constituting the flying object tracking system include monitoring satellites equipped with infrared detection devices and a group of communication satellites formed in inclined orbits.

[0148] <Configuration Example 2 of Satellite Information Transmission System 503> FIG. 30 is a diagram showing a configuration example of Example 2 of a satellite information transmission system 503 according to the present embodiment. FIG. 30 shows the satellite information transmission system 503 as viewed from the North Pole.

[0149] The second example of the satellite information transmission system 503 is composed of a first communication constellation 831, a second communication constellation 832, and ground equipment.

[0150] The first communication constellation 831 flies in an equatorial orbit. The first communication constellation 831 has a plurality of satellites each equipped with a first communication device that communicates with satellites in front of and behind it in the direction of travel in the same orbital plane, forming a circular communication network. The second communication constellation 832 flies in a sun-synchronous orbit. In the second communication constellation 832, a plurality of satellites each having a first communication device that communicates with satellites in front of and behind the satellite in the direction of travel in the same orbital plane form a circular communication network.

[0151] Each satellite of the first communications constellation 831 and the second communications constellation 832 comprises a second communications device with which the first communications constellation 831 and the second communications constellation 832 communicate. Each satellite of the first communication constellation 831 and the second communication constellation 832 transmits satellite information to ground facilities via the first communication constellation 831 and the second communication constellation 832.

[0152] Alternatively, each satellite of the first and second communications constellations may include communications equipment for communicating with a user satellite. The user satellites may transmit satellite information to ground facilities via a first communication constellation 831 and a second communication constellation 832 .

[0153] There are cases where satellite information acquired by a satellite flying in an equatorial orbit is transmitted to ground facilities installed in the mid- to high-latitude regions. In such cases, it is rational for equatorial satellites that form a circular communication network in the longitude direction and sun-synchronous satellites that form a circular communication network in the latitude direction to communicate with each other. If there is ground equipment at high latitudes where communication visibility can be ensured when a sun-synchronous satellite passes through the polar regions, it will be possible to transmit satellite information obtained by a satellite above the equator to ground equipment in almost real time with just one sun-synchronous orbital plane. It goes without saying that the first communication constellation and the second communication constellation may each include a communication device with a user satellite.

[0154] <Configuration Example 3 of Satellite Information Transmission System 503> FIG. 31 is a diagram showing a configuration example of Example 3 of a satellite information transmission system 503 according to the present embodiment. FIG. 31 shows the satellite information transmission system 503 as viewed from the North Pole.

[0155] The third example of the satellite information transmission system 503 is composed of a first communication constellation 831, a second communication constellation 832, a third communication constellation 833, and ground facilities.

[0156] The first communication constellation 831 flies in an equatorial orbit. The first communication constellation 831 has a plurality of satellites each equipped with a first communication device that communicates with satellites in front of and behind it in the direction of travel in the same orbital plane, forming a circular communication network. The second communication constellation 832 flies in a sun-synchronous orbit. In the second communication constellation 832, a plurality of satellites each having a first communication device that communicates with satellites in front of and behind the satellite in the direction of travel in the same orbital plane form a circular communication network. The third communication constellation 833 flies in an inclined orbit. The third communication constellation 833 also has a circular communication network formed by a plurality of satellites each equipped with a first communication device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane.

[0157] Each satellite of the first communications constellation 831, the second communications constellation 832 and the third communications constellation 833 comprises a second communications device. The second communication device is a communication device for communication between the first communication constellation and the second communication constellation, or between the second communication constellation and a third communication constellation, or between the third communication constellation and the first communication constellation.

[0158] Each satellite of the first communication constellation 831, the second communication constellation 832, and the third communication constellation 833 transmits satellite information to ground equipment via at least two of the first communication constellation 831, the second communication constellation 832, and the third communication constellation 833.

[0159] Alternatively, each satellite of the first communications constellation, the second communications constellation and the third communications constellation 833 may include a communications device for communicating with a user satellite. The user satellites may transmit satellite information to ground facilities via at least two of the first communications constellation 831, the second communications constellation 832, and the third communications constellation 833.

[0160] There are cases where satellite information acquired by equatorial orbit satellites is transmitted to ground facilities installed in the mid-latitudes. In such cases, it is reasonable for inclined orbit satellites that form a circular communication network in an inclined orbit flying in the longitude direction in the mid-latitudes, equatorial satellites that form a circular communication network in the longitude direction, and sun-synchronous satellites that form a circular communication network in the latitude direction to communicate with each other.

[0161] For example, if the ground equipment is located at 35 degrees north latitude, a satellite on an inclined orbit with an orbital inclination of 35 degrees will fly above the ground equipment in the longitude direction, which has the effect of ensuring a long communication time with the ground equipment. If the inclined orbit satellite group has multiple orbital planes with normal vectors distributed in the longitude direction, it has the effect of being able to transmit satellite information acquired by satellites above the equator to the ground equipment in almost real time.

[0162] <Configuration Example 4 of Satellite Information Transmission System 503> FIG. 32 is a diagram showing a configuration example of Example 4 of a satellite information transmission system 503 according to the present embodiment. FIG. 32 shows the satellite information transmission system 503 as viewed from the North Pole.

[0163] The fourth example of the satellite information transmission system 503 is composed of a first communication constellation 831a, a second communication constellation 832, and ground equipment.

[0164] The first communication constellation 831a flies in a sun-synchronous orbit. In addition, the first communication constellation 831a has a plurality of satellites each equipped with a first communication device that communicates with satellites in front and behind it in the direction of travel in the same orbital plane, forming a circular communication network. The second communication constellation 832 flies in a sun-synchronous orbit of an LST different from that of the first communication constellation 831a. In addition, the second communication constellation 832 has a circular communication network formed by a plurality of satellites each equipped with a first communication device that communicates with satellites in front and behind the satellite in the direction of travel on the same orbital plane.

[0165] Each satellite of the first communication constellation 831a and the second communication constellation 832 includes a second communication device with which the first communication constellation 831a and the second communication constellation 832 communicate when passing near the polar regions. Each satellite in the first communication constellation 831a and the second communication constellation 832 transmits satellite information to ground facilities via the first communication constellation 831a and the second communication constellation 832.

[0166] Sun-synchronous satellites are polar orbit satellites that pass over the vicinity of the polar regions. Therefore, the first communication constellation 831a and the second communication constellation 832 that form the circular communication network include satellites that can communicate over the vicinity of the polar regions. By transmitting satellite information to the circular communication network of the communication constellations of different LSTs, it is possible to transmit satellite information at a desired time period regardless of the latitude in which the ground equipment is installed.

[0167] <Configuration example 5 of the satellite information transmission system 503> FIG. 33 is a diagram showing a configuration example of Example 5 of a satellite information transmission system 503 according to the present embodiment. FIG. 33 shows the satellite information transmission system 503 as viewed from above the equator.

[0168] The fifth example of the satellite information transmission system 503 is made up of a first communication constellation 831, a second communication constellation 832a, and ground equipment.

[0169] The first communication constellation 831 flies in an equatorial orbit. The first communication constellation 831 has a plurality of satellites each equipped with a first communication device that communicates with satellites in front of and behind it in the direction of travel in the same orbital plane, forming a circular communication network. The second communication constellation 832a flies in an inclined orbit. In the second communication constellation 832a, a plurality of satellites each having a first communication device that communicates with satellites in front and behind the satellite in the same orbital plane in the direction of travel form a circular communication network.

[0170] Each satellite of the first communications constellation 831 and the second communications constellation 832a comprises a second communications device with which the first communications constellation 831 and the second communications constellation 832a communicate. Each satellite in the first communication constellation 831 and the second communication constellation 832a transmits satellite information to ground equipment via the first communication constellation 831 and the second communication constellation 832a.

[0171] According to the fifth example of the satellite information transmission system 503, there is an advantage that the satellite information acquired by the satellite in the equatorial orbit can be transmitted to the ground equipment installed in the mid-latitude zone. In addition, the time period during which the second communication constellation 832a flies above the ground equipment is known in advance by the planned orbit information. Therefore, when the second communication constellation 832a is composed of a plurality of orbital planes with different normal vectors, there is an advantage that the satellite information can be transmitted to the ground equipment in a desired time period.

[0172] As described in the first embodiment, the satellites are controlled by commands transmitted from the ground equipment. The ground equipment has a satellite constellation forming unit in a processor that forms a satellite constellation, and forms the satellite constellation by communicating with each satellite. The satellites are also provided with a satellite constellation forming unit, and the satellite constellation forming unit of each of the multiple satellites and the satellite constellation forming unit provided in the ground equipment work together to realize control of the satellite constellation. The satellite constellation forming unit of the satellite is provided in, for example, a satellite control device.

[0173] In the above first to sixth embodiments, each system and each device, such as the satellite monitoring system, the satellite information transmission system, the ground equipment, the communication satellite, the monitoring system, the component satellite, the communication satellite constellation, the satellite constellation, the artificial satellite, and the satellite, have been described as an independent functional block. However, the configuration of each system and each device does not have to be as in the above-mentioned embodiments. The functional blocks of each system and each device may have any configuration as long as they can realize the functions described in the above-mentioned embodiments. Furthermore, each system and each device may be a single device or a system composed of multiple devices. Furthermore, among the first to sixth embodiments, a plurality of parts or examples may be combined and implemented. Alternatively, a single part or example of these embodiments may be implemented. Additionally, any combination of these embodiments may be implemented, either as a whole or in part. That is, in the first to sixth embodiments, any combination of the embodiments is possible, or any component of each embodiment may be modified, or any component of each embodiment may be omitted.

[0174] It should be noted that the above-described embodiment is essentially a preferred example, and is not intended to limit the scope of the present disclosure, the scope of application of the present disclosure, and the scope of use of the present disclosure. The above-described embodiment can be modified in various ways as necessary. [Explanation of symbols]

[0175] 30 Satellite, 310, 112, 202 Satellite control device, 33, 122, 114, 204 Propulsion device, 34, 115, 205 Attitude control device, 35, 123, 116, 206 Power supply, 111, 201 Observation device, 32, 121, 113, 203 Communication device, 124, 117 Camera, 41 First communication device, 42 Second communication device, 43 Third communication device, 44 Communication satellite group, 401 Communication satellite, 402 Data relay satellite, 403 Weather satellite, 404 Observation satellite, 405 First observation and monitoring satellite, 406 Positioning satellite, 407 Second observation and monitoring satellite, 408 Space station, 409 Lunar planetary exploration satellite, 410 Exploration satellite, 411 Transport vehicle, 421 Optical monitoring satellite, 422 Infrared monitoring satellite, 423 Radio wave monitoring satellite, 424 Service satellite, 425 Debris removal satellite, 51 Critical infrastructure, 510 Infrastructure satellite group, 511 Infrastructure satellite, 52 Monitoring satellite group, 521, 521a, 521b, 521c Monitoring satellite, 53 Monitoring center, 54 Ground equipment for each infrastructure, 530 User satellite group, 531 User satellite, 542 Radio communication terminal, 544 Optical communication terminal, 590 Monitoring information, 61 First satellite, 62 Second satellite, 63 Third satellite, 644 Fourth satellite, 64 Transmission / reception switching device, 65 Two-way communication terminal, 601 First satellite group, 602 Second satellite group, 603 Third satellite group, 500 Satellite monitoring system, 501, 503 Satellite information transmission system, 502 Monitoring system, 701, 702 Ground equipment, 710 Monitoring management unit, 720 memory unit, 80 artificial satellite, 81 information processing device, 801 communication satellite constellation, 802 satellite constellation, 810 first satellite constellation, 811, 812 constituent satellites, 820 second satellite constellation, 831, 831a first communication constellation, 832, 832a second communication constellation, 833 third communication constellation, 910 processor, 921 memory, 922 auxiliary storage device, 930 input interface, 940 output interface, 941 display device, 950 communication device.

Claims

1. A critical infrastructure, which is a social infrastructure in outer space, is composed of a group of infrastructure satellites that fly in a low earth orbit (LEO) at an orbital altitude of 500 km or more and 2000 km or less; a monitoring satellite group consisting of monitoring satellites that fly in an orbit at an altitude of 2000 km or less and monitor the infrastructure satellite group and perform on-orbit services; a ground facility installed on the ground and configured to transmit and receive information to and from each infrastructure satellite of the infrastructure satellite group; A monitoring center is installed on the ground and transmits and receives information to and from the monitoring satellite. Equipped with the infrastructure satellite constellation includes a communications satellite constellation of communications satellites; The communications satellite constellation includes: The satellites fly in an evenly spaced orbit with an orbital altitude and inclination that results in a sun-synchronous orbit that completes an integral number of revolutions per day. The communications satellite, It communicates with the communications satellites flying in front and behind it, The communications satellites include: a first satellite in communication with the ground facility; a second satellite in communication with the monitoring satellite; A third satellite that only communicates with the communications satellites flying in front and behind it. Equipped with The monitoring satellite and the monitoring center are: A communication satellite used in a satellite monitoring system that transmits and receives information via the group of communication satellites, a first communication device for communicating with the ground equipment; three second communication devices for communicating among the infrastructure satellites; Equipped with A communications satellite that flies in the same orbital plane and communicates simultaneously with a monitoring satellite or a user satellite.

2. A critical infrastructure, which is a social infrastructure in outer space, is composed of a group of infrastructure satellites that fly in a low earth orbit (LEO) at an orbital altitude of 500 km or more and 2000 km or less; a ground facility installed on the ground for transmitting and receiving information to and from each infrastructure satellite of the infrastructure satellite group; Equipped with The infrastructure satellite constellation includes: a communications constellation consisting of communications satellites; a user satellite group consisting of user satellites that use the communications satellite group as a communication line, The communications satellite constellation includes: The satellites fly in an evenly spaced orbit with an orbital altitude and inclination that results in a sun-synchronous orbit that completes an integral number of revolutions per day. The communications satellite, It communicates with the communications satellites flying in front and behind it, The communications satellite constellation includes: a first satellite in communication with the ground facility; a second satellite in communication with the user satellite; A third satellite that only communicates with the communications satellites flying in front and behind it. Equipped with The user satellite and the ground facility include: A communications satellite used in a satellite information transmission system that transmits and receives information via the communications satellite group, a first communication device for communicating with the ground equipment; three second communication devices for communicating among the infrastructure satellites; Equipped with A communications satellite that flies in the same orbital plane and communicates simultaneously with a monitoring satellite or a user satellite.

3. A critical infrastructure, which is a social infrastructure in outer space, is composed of a group of infrastructure satellites that fly in a low earth orbit (LEO) at an orbital altitude of 500 km or more and 2000 km or less; a monitoring satellite group consisting of monitoring satellites that fly in an orbit at an altitude of 2000 km or less and monitor the infrastructure satellite group and perform on-orbit services; a ground facility installed on the ground and configured to transmit and receive information to and from each infrastructure satellite of the infrastructure satellite group; A monitoring center is installed on the ground and transmits and receives information to and from the monitoring satellite. Equipped with the infrastructure satellite constellation includes a communications satellite constellation of communications satellites; The communications satellite constellation includes: The satellites fly in an evenly spaced orbit with an orbital altitude and inclination that results in a sun-synchronous orbit that completes an integral number of revolutions per day. The communications satellite, It communicates with the communications satellites flying in front and behind it, The communications satellite constellation includes: a first satellite in communication with the ground facility; a second satellite in communication with the monitoring satellite; A third satellite that only communicates with the communications satellites flying in front and behind it. Equipped with The monitoring satellite and the monitoring center are: A communication satellite used in a satellite monitoring system that transmits and receives information via the group of communication satellites, a first communication device for communicating with the ground equipment; a second communication device for communicating between the infrastructure satellites; a third communication device for communicating with the monitoring satellite or the user satellite; A communications satellite comprising:

4. A critical infrastructure, which is a social infrastructure in outer space, is composed of a group of infrastructure satellites that fly in a low earth orbit (LEO) at an orbital altitude of 500 km or more and 2000 km or less; a ground facility installed on the ground for transmitting and receiving information to and from each infrastructure satellite of the infrastructure satellite group; Equipped with The infrastructure satellite constellation includes: a communications constellation consisting of communications satellites; a user satellite group consisting of user satellites that use the communications satellite group as a communication line, The communications satellites include: The satellites fly in an evenly spaced orbit with an orbital altitude and inclination that results in a sun-synchronous orbit that completes an integral number of revolutions per day. The communications satellite, It communicates with the communications satellites flying in front and behind it, The communications satellites include: a first satellite in communication with the ground facility; a second satellite in communication with the user satellite; A third satellite that only communicates with the communications satellites flying in front and behind it. Equipped with The user satellite and the ground facility include: A communications satellite used in a satellite information transmission system that transmits and receives information via the communications satellite group, A first communication device that communicates with the ground equipment; A second communication device for communicating between the infrastructure satellites; a third communication device for communicating with the monitoring satellite or the user satellite; A communications satellite comprising:

5. a first satellite constellation consisting of three or more satellites working together to monitor the Earth, airborne vehicles, and space objects; a ground facility for transmitting and receiving information to and from a satellite constellation constituting the first satellite constellation; A second satellite constellation consisting of six or more communication satellites that fly in a sun-synchronous orbit at an altitude of 800 km or more and communicate with satellites flying in front of and behind the same orbital plane, relaying satellite information. Equipped with The satellites constituting the first satellite constellation include: A monitoring system that transmits and receives information to and from the ground equipment via the second satellite constellation, The first satellite constellation comprises: It orbits an inclined circular orbit at an altitude of 1,000 km to 6,000 km multiple times per day. A plurality of orbital planes formed by a plurality of satellites included in the first satellite constellation include: A constituent satellite of the first satellite constellation used in a monitoring system in which the normals of each satellite are offset by an equal angle in the azimuth direction and the flying positions of each orbital plane are synchronously controlled.

6. a first satellite constellation consisting of three or more satellites working together to monitor the Earth, airborne vehicles, and space objects; a ground facility for transmitting and receiving information to and from a satellite constellation constituting the first satellite constellation; A second satellite constellation consisting of six or more communication satellites that fly in a sun-synchronous orbit at an altitude of 800 km or more and communicate with satellites flying in front of and behind the same orbital plane, relaying satellite information. Equipped with The satellites constituting the first satellite constellation include: A monitoring system that transmits and receives information to and from the ground equipment via the second satellite constellation, The first satellite constellation comprises: It orbits an inclined circular orbit at an altitude of 1,000 km to 6,000 km multiple times per day. A plurality of orbital planes formed by a plurality of satellites included in the first satellite constellation include: A constituent satellite of the second satellite constellation used in a monitoring system in which the normals of each satellite are shifted by an equal angle in the azimuth direction and the flying positions of each orbital plane are synchronously controlled.

7. A satellite information transmission system for relaying satellite information between a user satellite constellation orbiting the Earth and a ground facility, comprising: A communications satellite constellation consisting of six or more communications satellites that orbit a sun-synchronous orbit in a low earth orbit (LEO: Low Earth Orbit) at an orbital altitude of 500 km or more and 2000 km or less, in an evenly spaced arrangement, and communicate with communications satellites flying in front of and behind the same orbital plane, The communications satellite, It communicates with the communications satellites flying in front and behind it, The communications satellites include: a first satellite in optical communication with the ground facility; a second satellite in optical communication with the user satellite; A third satellite that only communicates with the communications satellites flying in front and behind it. Equipped with A communications satellite used in a satellite information transmission system that transmits radio waves between communications satellites flying in front of and behind it.

8. The system includes at least one of a computer or a supercomputer equipped with AI (Artificial Intelligence) and a cloud server or an edge server as an information processing device, The satellite flies in a sun-synchronous orbit at 06:00 LST (Local Sun Time) or 18:00 LST. The satellite has a solar cell oriented on the side where sunlight is incident, and a heat dissipation surface of the information processing device on the side opposite to the sunlight incidence.

9. A communications satellite constellation flying in a sun-synchronous orbit at 06:00 LST (Local Sun Time) or 18:00 LST, A communications satellite equipped with a communications device with the ground, A communications satellite constellation is a circular communications network formed by communication satellites flying in front of and behind each other in the same orbital plane, equipped with communication devices that allow them to communicate with each other.

10. A satellite constellation flying in a sun-synchronous orbit at 06:00 LST (Local Sun Time) or 18:00 LST, A satellite comprising a computer or supercomputer equipped with AI (Artificial Intelligence), and at least one of a cloud server and an edge server as an information processing device, a solar cell oriented on a sunlight incident side, and a heat dissipation surface of the information processing device on the opposite side to the sunlight incident side; a satellite having a communication device with the ground; A satellite constellation is a circular communications network formed by satellites flying in front of and behind each other in the same orbital plane, equipped with communication devices that allow them to communicate with each other.

11. A communications satellite constellation flying in a sun-synchronous orbit at 06:00 LST (Local Sun Time) or 18:00 LST, A communications satellite equipped with a communications device with the ground, A satellite that constitutes a communications satellite constellation, which is equipped with communication devices that allow communication between communications satellites flying in front of and behind the same orbital plane to form a circular communications network.

12. A satellite constellation flying in a sun-synchronous orbit at 06:00 LST (Local Sun Time) or 18:00 LST, A satellite comprising a computer or supercomputer equipped with AI (Artificial Intelligence), and at least one of a cloud server and an edge server as an information processing device, a solar cell oriented on a sunlight incident side, and a heat dissipation surface of the information processing device on the opposite side to the sunlight incident side; a satellite having a communication device with the ground; A satellite that flies in front of and behind the same orbital plane and is equipped with communication devices to communicate with each other, forming a circular communication network that makes up a satellite constellation.

13. A constellation of user satellites flying in a Low Earth Orbit (LEO), which is an Earth orbit with an altitude of 500 km or more and 2000 km or less; A communications satellite constellation consisting of a plurality of communications satellites flying in a sun-synchronous orbit at LST06:00 or LST18:00; Ground facilities and A satellite information transmission system comprising: In the group of communications satellites, each communications satellite communicates with a communications satellite flying in front of or behind it, a first satellite in communication with the ground facility; and a second satellite in communication with the user satellite; The user satellite and the ground facility include: A satellite that constitutes a satellite information transmission system that transmits and receives information via the group of communications satellites.

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