Ground equipment

Abstract

To provide a technique for transmitting satellite information acquired by a monitoring system to ground equipment approximately in real time, and for controlling each satellite approximately in real time.SOLUTION: In a monitoring system, satellites constituting a first satellite constellation 831 conduct information exchange with ground equipment via a second satellite constellation 832. The first satellite constellation 831 orbits an inclined circular orbit multiple times per day. In a plurality of orbital planes formed by the plurality of satellites included in the first satellite constellation 831, their mutual normal lines deviate respectively at equal angles in an azimuth direction. In the ground equipment, flight positions of the respective orbital planes are synchronously controlled, and information is transmitted via the first satellite constellation 831 and the second satellite constellation 832, and the satellites constituting the first satellite constellation 831 and the second satellite constellation 832 respectively are controlled according to commands.SELECTED DRAWING: Figure 31

Description

Technical Field

[0001] The present disclosure relates to ground facilities, communication satellites, component satellites, artificial satellites, communication satellite constellations, satellite constellations, and satellites.

Background Art

[0002] Satellite-based social infrastructure, such as information exchange with remote or border areas via communication satellites, weather forecasting using images of meteorological satellite sunflowers, and utilization of geospatial information by quasi-zenith positioning satellites, has become established in social life. These groups of practical satellites have become critical infrastructure indispensable for social life. On the other hand, due to factors such as debris collisions caused by an increase in the number of objects in the space environment, the number of dangerous events involving the risk of failure or loss of critical infrastructure is increasing. Therefore, there is a need for a mechanism to monitor critical infrastructure and take risk avoidance actions 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

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a group of satellites flying in a low Earth orbit (LEO), when an emergency situation requiring immediate response occurs, if an infrastructure satellite is flying on the far side of the Earth, there is a problem that communication with the monitoring center cannot be ensured. The low Earth orbit is, for example, an orbit with an altitude of 500 km or more and 2000 km or less. LEO is an abbreviation for Low Earth Orbit. Patent Document 1 does not disclose a method for monitoring critical infrastructure in a low Earth orbit.

[0006] The present disclosure aims to ensure a communication environment between a monitoring satellite and a monitoring center in a group of satellites flying in a low Earth orbit. In particular, it aims to transmit satellite information obtained by a monitoring system to ground facilities almost in real time and control each satellite almost in real time.

Means for Solving the Problem

[0007] According to the present disclosure a first satellite constellation in which a group of three or more satellites cooperate to monitor the Earth, flying objects, and space objects, ground facilities that exchange information with the satellites constituting the first satellite constellation, a second satellite constellation in which a group of six or more communication satellites flying in a sun-synchronous orbit with an altitude of 800 km or more in an equally spaced arrangement and communicating with satellites flying in front of and behind on the same orbital plane cooperate to relay satellite information and a ground facility included in a monitoring system comprising the satellites constituting the first satellite constellation exchange information with the ground facility via the second satellite constellation, the first satellite constellation circles an inclined circular orbit with an altitude of 1000 km or more and 6000 km or less multiple times a day, a plurality of orbital planes formed by a plurality of satellites included in the first satellite constellation Their normal lines are shifted by equal angles in the azimuth direction, and the flight positions of each orbital plane are synchronously controlled. The ground facility is Transmits information via the first satellite constellation and the second satellite constellation, and controls the satellites constituting each of the first satellite constellation and the second satellite constellation by commands.

Advantages of the Invention

[0008] In the ground facility according to the present disclosure, the satellite information acquired by the monitoring system can be transmitted to the ground facility almost in real time, and each satellite can be controlled almost in real time, which has the effect.

Brief Description of the Drawings

[0009]

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[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each figure, 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. Also, in the following drawings, the size relationships of the respective configurations may be different from the actual ones. Further, in the description of the embodiments, directions or positions such as "up", "down", "left", "right", "front", "rear", "front", and "back" may be indicated. Those notations are only for convenience of explanation and do not limit the arrangement and orientation of the configurations 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 the satellite monitoring system 500 according to the present embodiment. The satellite monitoring system 500 includes a group of monitoring satellites 52 that monitor the critical infrastructure 51 and a monitoring center 53. The satellite monitoring system 500 may include the critical infrastructure 51 in addition to the group of monitoring satellites 52 and the monitoring center 53. The monitoring satellite 521 is also referred to as a monitoring satellite or a monitoring device.

[0012] The critical infrastructure 51 is an infrastructure in space. Specific examples of the critical infrastructure 51 are formed by a group of satellites that constitute the following social infrastructure. · Information exchange with remote or border areas via communication satellites · Weather forecasting using images of the meteorological satellite Hinode · Utilization of geospatial information by quasi-zenith positioning satellites Also, the satellites that constitute the critical infrastructure 51 are referred to as 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 exchanges information with the monitoring satellites 521 of the monitoring satellite group 52. The monitoring satellites 521 of the monitoring satellite group 52 and the monitoring center 53 exchange information via the communication devices equipped on the infrastructure satellites 511.

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

[0015] In addition, the ground facilities 54 for each infrastructure corresponding to the critical infrastructure 51 are installed on the ground. The ground facilities 54 for each infrastructure are ground facilities that are installed on the ground and conduct information exchange with each infrastructure satellite of the infrastructure satellite group 510.

[0016] Due to factors such as debris collisions caused by the increase in the number of objects in the space environment, the number of dangerous events accompanied by the risk of failure or loss of the critical infrastructure 51 is increasing. Therefore, a mechanism is needed to monitor the critical infrastructure 51 and take risk avoidance actions if necessary.

[0017] The monitoring satellite group 52 includes the infrastructure satellite 511 equipped with a communication device for communicating with the monitoring center 53 as the monitoring satellite 521. The monitoring satellite 521 includes all or part 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 performs on-orbit services for the infrastructure satellite 511. The debris removal satellite 425 removes debris.

[0018] The on-orbit services include all or part of capture, inspection, repair, fuel replenishment, movement, orbit departure (ADR: Active Debris Removal), and laser irradiation.

[0019] The monitoring service provided by the monitoring satellite constellation 52 is easier to understand when considered in analogy with the roles of the eyes, ears, hands, and mouth. To achieve the purpose of visually monitoring the critical infrastructure 51 with a satellite, methods such as visually monitoring suspicious objects such as debris using an optical telescope or radar images are effective. In addition, a method of monitoring abnormal temperature environments by infrared detection is also effective.

[0020] In addition, for the monitoring service that listens aurally, there is a purpose of monitoring radio waves in outer space where sound waves do not propagate. To achieve the purpose of aurally monitoring the critical infrastructure 51 with a satellite, a method of receiving radio waves flying around and monitoring the radio wave situation that may cause malfunction is effective.

[0021] In addition, as an extended service of monitoring, on-orbit services can be cited as an analogy to the role of operating with hands. Examples of on-orbit services include services such as capturing, inspecting, and repairing malfunctioning satellites. It also includes services such as refueling satellites that have run out of fuel, mobile services that move the position of the service, and active debris removal (ADR) of satellites that cannot deorbit on their own after the end of their lifespan. It also includes services such as irradiating lasers to monitor the distance to suspicious objects such as debris.

[0022] In this way, it is expected that the monitoring satellite 521 will realize the roles of the eyes, ears, or hands. However, there are limitations in the communication means for transmitting the monitoring information 590, which is the role of the mouth, and thus ingenuity is required.

[0023] In this embodiment, the infrastructure satellite 511 is used as the monitoring satellite 521 that undertakes the role of the mouth, that is, the monitoring satellite 521 that transmits the monitoring information 590. The monitoring satellite 521 includes the infrastructure satellite 511 that serves as the mouth. Also, the infrastructure satellite 511 includes the monitoring satellite 521 that serves as the mouth. That is, in the satellite monitoring system 500, there is a satellite that is both the monitoring satellite 521 and the infrastructure satellite 511. Here, such a satellite was mainly described as the infrastructure satellite 511 that serves as the mouth, but it may also be a satellite that serves as the eyes, ears, and hands.

[0024] As shown in FIG. 1, the monitoring satellite 521 that conducts long-distance communication includes the communication satellite 401 and the data relay satellite 402 in the first satellite group 601. Also, it includes the communication satellite 401 in the second satellite group 602. Also, it includes the lunar planetary exploration satellite 409 in the third satellite group 603. The monitoring satellite 521 that conducts short-distance communication includes the meteorological satellite 403, the positioning satellite 406, and the observation satellite 404 in the first satellite group 601.

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

[0026] FIG. 2 is a configuration example of the monitoring center 53 according to the present embodiment. The monitoring center 53 is also referred to as the ground facility 701 installed on the ground. Here, it will be described as the ground facility 701.

[0027] The ground facility 701 is equipped with a computer. The ground facility 701 includes a processor 910 and 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 these other hardware.

[0028] As an example of functional elements, the ground facility 701 includes a monitoring management unit 710 and a storage unit 720. The monitoring information 590 is stored in the storage unit 720.

[0029] The function of the monitoring management unit 710 is 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. Also, the storage unit 720 may be provided separately in the memory 921 and the auxiliary storage device 922.

[0030] The ground facility 701 exchanges the monitoring information 590 with the monitoring satellite 521 via the infrastructure satellite 511. The monitoring management unit 710 realizes a function of coping with the risk of failure or loss of the critical infrastructure 51 using the monitoring information 590 exchanged with the monitoring satellite 521. For example, the monitoring management unit 710 realizes functions such as warning of danger, prevention of danger, or avoidance of 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 facility 701 and the satellite monitoring system 500.

[0032] The processor 910 is an IC (Integrated Circuit) that performs arithmetic processing. Specific examples of the processor 910 are a CPU, a DSP (Digital Signal Processor), and a GPU (Graphics Processing Unit).

[0033] The memory 921 is a storage device that temporarily stores data. Specific examples of the memory 921 are SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). The auxiliary storage device 922 is a storage device that stores data. A specific example of the auxiliary storage device 922 is an HDD. Also, the auxiliary storage device 922 may be a portable storage medium such as an SD (registered trademark) memory card, a CF, a 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 that is connected to an input device such as a mouse, a keyboard, or a touch panel. Specifically, the input interface 930 is a USB (Universal Serial Bus) terminal. Note that the input interface 930 may be a port that is connected to a LAN (Local Area Network). 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 has a receiver and a transmitter. Specifically, the communication device 950 is a communication chip or a NIC (Network Interface Card).

[0036] The monitoring management program is loaded into the processor 910 and executed by the processor 910. In the memory 921, not only the monitoring management program but also the OS (Operating System) is stored. The processor 910 executes the monitoring management program while executing the OS. The monitoring management program and the OS may be stored in the auxiliary storage device. The monitoring 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 part or all of the monitoring management program may be incorporated into the OS.

[0037] The ground facility 701 may include a plurality of 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 in the same way as the processor 910.

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

[0039] The "section" of the monitoring management section 710 may be read as "processing", "procedure", or "step". Also, the "processing" of the monitoring management processing may be read as "program", "program product", or "computer-readable storage medium storing a program". The monitoring management program causes a computer to execute each process, each procedure, or each step obtained by reading the "section" of the monitoring management section as "processing", "procedure", or "step". Also, the monitoring management method is a method performed by the ground facility 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. Further, the monitoring management program may be provided as a program product.

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

[0041] FIG. 3 is a configuration example of a satellite 30 which is an example of a celestial object according to the present embodiment. The satellite 30 includes a satellite control device 310, a communication device 32, a propulsion device 33, an attitude control device 34, and a power supply device 35. In addition, it includes components for realizing various functions, but in FIG. 3, the satellite control device 310, the communication device 32, the propulsion device 33, the attitude control device 34, and the power supply device 35 will be described. The satellite 30 is an example of a celestial 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 according to various commands transmitted from the ground device. 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 itself to the ground device. Also, the communication device 32 receives various commands transmitted from the ground device. The propulsion device 33 is a device that applies a propulsion force to the satellite 30 and changes the speed of the satellite 30. Specifically, the propulsion device 33 is an apogee kick motor or a chemical propulsion device, or an electric propulsion device. The apogee kick motor (AKM) is an upper-stage propulsion device used for injecting an artificial satellite into orbit and is also called an apogee motor (when using a solid rocket motor) or an apogee engine (when using a liquid engine). The chemical propulsion device is a thruster using a single - component or two - component fuel. As the electric propulsion device, an ion engine or a Hall thruster is used. The apogee kick motor is the name of the device used for orbit transfer and may be a type of chemical propulsion device. 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 direction. The attitude control device 34 changes each attitude element to a desired direction. Or, 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 device 35 includes devices such as solar cells, batteries, and power control devices, and supplies power to each device mounted on the satellite 30.

[0043] The processing circuit provided in the satellite control device 310 will be described. The processing circuit may be dedicated hardware or 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. That is, the processing circuit can be realized by hardware, software, firmware, or a combination thereof. Specifically, the dedicated hardware is a single circuit, a composite circuit, a programmed processor, a parallel - programmed processor, an ASIC, an FPGA, or a combination thereof. ASIC is the abbreviation of Application Specific Integrated Circuit. FPGA is the abbreviation of Field Programmable Gate Array.

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

[0045] Based on FIG. 4, the configuration of the communication satellite 401 will be described. The communication satellite 401 includes a communication 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 pointing direction of the first directional antenna 121E or the second directional antenna 121W.

[0046] The communication satellite 401 can visually capture the observation satellite and other space objects flying in a geostationary orbit or an orbit near the geostationary orbit. Therefore, it is possible to visually confirm that there are no obstacles around the communication satellite 401 that cause interference and noise due to communication. The other space object is a space object different from the space object observed by the observation satellite.

[0047] By arranging the camera 124 so that the direction from the communication satellite 401 to the earth becomes the line-of-sight vector, the observation satellite 404 and other space objects flying in a geostationary orbit or an orbit near the geostationary orbit can be visually captured. Furthermore, it becomes possible to estimate the position of other space objects on the orbit. Therefore, it is possible to visually confirm that there is no interference and noise due to communication around the communication satellite 401.

[0048] Based on FIG. 5, the configuration of the observation satellite 404 will be described. 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 device 111 is a device for observing cosmic objects. The observation device 111 is also referred to as monitoring equipment. The camera 117 is, for example, a wide-angle camera that points to the communication satellite 401.

[0049] The camera 117 can visually capture the communication satellite 401 and other cosmic objects flying in a geostationary orbit or an orbit near the geostationary orbit. Therefore, it is possible to visually confirm that the environment around the observation satellite 404 is free from communication interference and noise.

[0050] By arranging the camera 117 so that the direction from the observation satellite 404 to the communication satellite 401 becomes the line-of-sight vector, the communication satellite 401 and other cosmic objects flying in a geostationary orbit or an orbit near the geostationary orbit can be visually captured. Furthermore, it becomes possible to estimate the positions of other cosmic objects on the orbit. Therefore, it is possible to visually confirm that the environment around the observation satellite 404 is free from communication interference and noise.

[0051] Based on FIG. 6, another example of the configuration of the observation satellite 404 will be described. 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 cosmic objects. The observation device 201 is a device that detects cosmic objects with an optical system. The observation device 201 photographs cosmic objects flying at altitudes different from the orbital altitude of the observation satellite with an optical system. Specifically, the observation device 201 is a visible optical sensor. Observation device 201 generates observation data. The observation data is data obtained by the observation performed by the observation device 201. For example, the observation data corresponds to data representing an image in which a celestial object is reflected.

[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 various commands transmitted from the ground facilities.

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

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

[0056] <Example of the overall configuration of the satellite monitoring system 500> In the present embodiment, the critical infrastructure 51 is a social infrastructure in space. The critical infrastructure 51 is composed of an infrastructure satellite group 510 including infrastructure satellites 511 flying in a low earth orbit (LEO) with an orbital altitude of 500 km or more and 2000 km or less. The monitoring satellite group 52 consists of monitoring satellites 521 flying in orbits with an orbital altitude of 2000 km or less, monitoring the infrastructure satellite group 510, and performing on-orbit services. The ground facility 54 for each infrastructure is an example of a ground facility installed on the ground and performing information exchange with each infrastructure satellite 511 of the infrastructure satellite group 510. The monitoring center 53 is an example of ground facilities installed on the ground for information exchange with the monitoring satellite 521.

[0057] As shown in FIG. 1, the infrastructure satellite group 510 includes a communication satellite group 44 composed of communication satellites 401.

[0058] The communication satellite group 44 flies in an orbit with an orbital altitude and orbital inclination angle that form a sun-synchronous orbit that makes an integer number of revolutions per day, and is arranged approximately evenly. The communication satellite 401 communicates with communication satellites flying before and after it. The communication satellite group 44 includes a first satellite 61 that communicates with ground facilities such as the ground facility 54 for each infrastructure, a second satellite 62 that communicates with the monitoring satellite 521b, and a third satellite 63 that only communicates with communication satellites flying before and after it. The monitoring satellite 521b and the monitoring center 53 exchange information via the communication satellite group 44.

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

[0060] The communication satellite 401 that is an example of the first satellite 61 is provided with a first communication device 41 for communication with ground facilities. The communication satellite 401 that is an example of the first satellite 61 is also provided with a second communication device 42 for communication between infrastructure satellites.

[0061] The communication satellite 401, which is an example of the third satellite 63 that only communicates with communication satellites flying back and forth, includes a second communication device 42 for communication between infrastructure satellites.

[0062] In a group of satellites flying in LEO, when the infrastructure satellite 511 is flying on the back side of the Earth, there may be a case where the communication environment with the monitoring center 53 cannot be ensured even if an emergency situation requiring emergency response occurs. However, according to the satellite monitoring system 500 according to the present embodiment, it has an environment in which a plurality of communication satellites communicate with each other, and monitoring information can be exchanged via the plurality of communication satellites from the back side of the Earth. Therefore, there is an effect that the monitoring information can be exchanged with the monitoring center at any time and anywhere. For this reason, there is an effect that when a dangerous space object such as debris approaches the infrastructure satellite 511, it can immediately take a danger avoidance action.

[0063] <Configuration Example 1 of Communication Satellite Group 44> Each communication satellite 401 of the communication satellite group 44 flies in a sun-synchronous orbit with an orbital altitude of about 1666 km and orbits 12 times a day. The communication satellite group 44 is composed of five or more communication satellites 401.

[0064] When the orbital altitude of orbiting 12 times a day is about 1666 km and the orbital inclination angle is set to 77° (180° - 103°), it becomes a sun-synchronous orbit. When five satellites fly in this orbit with an equal phase, the radius of the inscribed circle of the formed pentagon is larger than the radius of the Earth, so the communication field of view between the satellites can be ensured. Assuming that the altitude at which the influence of the atmosphere can be ignored is 300 km, if there are six or more satellites, there is an effect that a communication line can be ensured at an altitude of 585 km or more above the ground surface. In addition, since it revisits at the same time every day at the same latitude every two hours, there is an effect that information can be exchanged with ground facilities at a frequency of every two hours at a fixed time every day.

[0065] <Configuration Example 2 of Communication Satellite Group 44> Each communication satellite 401 in the communication satellite group 44 flies in a sun-synchronous orbit with an orbital altitude of about 1248 km and makes 13 orbits per day. The communication satellite group 44 is composed of six or more communication satellites.

[0066] If the orbital altitude of 13 orbits per day is about 1248 km and the orbital inclination angle is set to 79° (180° - 101°), it becomes a sun-synchronous orbit. When six satellites fly in this orbit with an equal phase, the radius of the inscribed circle of the formed hexagon is larger than the radius of the Earth, so the communication field of view between the satellites can be ensured. Assuming that the altitude at which the influence of the atmosphere can be ignored is 300 km, if there are seven or more satellites, there is an effect that a communication line can be secured at an altitude of 491 km or more above the ground surface. Since it revisits the same latitude at the same time every day, every 111 minutes, there is an effect that information can be exchanged between ground facilities at a frequency of every 111 minutes at a fixed time every day.

[0067] <Configuration Example 3 of Communication Satellite Group 44> Each communication satellite 401 in the communication satellite group 44 flies in a sun-synchronous orbit with an orbital altitude of about 881 km and makes 14 orbits per day. The communication satellite group 44 is composed of seven or more communication satellites.

[0068] FIG. 8 is a diagram showing Configuration Example 3 of the communication satellite group 44 according to the present embodiment. If the orbital altitude of 14 orbits per day is about 881 km and the orbital inclination angle is set to 81° (180° - 99°), it becomes a sun-synchronous orbit. If the orbital parameters for sun-synchronization are set at an orbital altitude of 881 km, an orbit of 14 orbits per day can be realized. When seven satellites fly in this orbit with an equal phase, the radius of the inscribed circle of the formed hexagon is larger than the radius of the Earth, so the communication field of view between the satellites can be ensured. Assuming that the altitude at which the influence of the atmosphere can be ignored is 300 km, if there are eight or more satellites, there is an effect that a communication line can be secured at an altitude of 327 km or more above the ground surface.

[0069] Since it revisits the same latitude at the same time every day, every 103 minutes, there is an effect that ground facilities can exchange information with it at a fixed time every day at a frequency of every 103 minutes. Note that the orbital inclination angle of 77° is the same as 103° depending on the definition. Also, the orbital inclination angle of 79° is the same as 101° depending on the definition. Further, the orbital inclination angle of 81° is the same as 99° depending on the definition.

[0070] <Configuration Example 4 of Communication Satellite Group 44> The communication satellite group 44 is in a sun-synchronous orbit and is composed of satellite groups in two orbital planes of LST 9:00 and LST 15:00. LST is an abbreviation for Local Sun Time.

[0071] FIG. 9 is a diagram showing Configuration Example 4 of the communication satellite group 44 according to the present embodiment. Sun-synchronous orbits are widely used in earth observation satellites. In optical satellites, the vicinity of LST 10:30 and LST 13:30 with good sunlight conditions is widely used. Also, in radar satellites, LST 06:00 and LST 18:00, which are advantageous for solar power generation, are widely used. When the orbital altitude of the communication satellite is 881 km, the inscribed circle of a regular octagon is 6727 km, so a communication line with a monitoring satellite at any LST can be ensured. Note that the monitoring satellite may be a user satellite that uses the communication satellite group 44 as a communication line. Therefore, if communication satellites are deployed in two orbital planes of LST 09:00 and LST 15:00, there is an effect that communication can be achieved with all satellite groups widely used in earth observation.

[0072] <Communication Method of Communication Satellite Group 44> FIG. 10 is a diagram showing the communication method of the communication satellite group 44 according to the present embodiment. The communication satellite 401 and the monitoring satellite 521 are equipped with a two-way communication terminal 65 having a transmission / reception switching device 64 that realizes reception and transmission by switching between a reception function and a transmission function. The ground facility 701, which is the monitoring center 53, operates the transmission / reception switching device 64 based on the data volume α of the command transmitted to the monitoring satellite 521 and the data volume β of the monitoring data and telemetry received from the monitoring satellite 521, so that the reception time and transmission time ratio of the monitoring satellite 521 is α to β. Specifically, the ground facility 701 operates the transmission / reception switching device 64 based on the data volume α of the command transmitted to the monitoring satellite 521 and the data volume β of the monitoring report data received from the monitoring satellite 521, so that the ratio of the reception operation time when the receiver function operates in the bidirectional communication terminal 65 to the transmission operation time when the transmitter function operates is α to β. The monitoring satellite 521 and the ground facility 701 exchange information 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, mainly, the points added to or different from Embodiment 1 will be described. Note that the same components as those in Embodiment 1 may be denoted by the same reference numerals, and the description thereof may be omitted.

[0075] In Embodiment 1, mainly, the configuration in which the monitoring satellite 521 and the monitoring center 53 exchange information via the communication satellite group 44 included in the infrastructure satellite group 510 has been described. In this embodiment, a satellite information transmission system 501 in which the user satellite 531 and the ground facility 702 exchange information via the communication satellite group 44 included in the infrastructure satellite group 510 will be described.

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

[0077] In FIGS. 11 and 12, the first satellite 61 communicating with the ground facility 702 is represented by "First", the second satellite 62 communicating with the user satellite 531 is represented by "Second", and the third satellite 63 that only communicates with the communication satellites flying before and after is represented by "Third".

[0078] The satellite information transmission system 501 includes a critical infrastructure 51 composed of an infrastructure satellite group 510 flying in LEO, and a ground facility 702 that exchanges information with each infrastructure satellite of the infrastructure satellite group 510. The infrastructure satellite group 510 is composed of a communication satellite group 44 and a user satellite group 530 composed of user satellites 531 that use the communication satellite group 44 as a communication line.

[0079] As shown in FIGS. 11 and 12, the communication satellite group 44 flies in an orbit with an orbital altitude and orbital inclination angle that result in a sun-synchronous orbit that makes an integer number of revolutions per day, with the orbits arranged approximately evenly. The communication satellite 401 communicates with the communication satellites flying before and after. The communication 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 communication satellites flying before and after. The user satellite 531 and the ground facility 702 exchange information via the communication satellite group 44.

[0080] <Configuration Examples 1 to 4 of the Communication Satellite Group 44> Also, for the configuration examples of the communication satellite group 44 according to the present embodiment, the same configurations as Configuration Examples 1 to 4 of the communication satellite group 44 described in the embodiment can be applied.

[0081] <Communication method of communication satellite group 44> Regarding the communication method of the communication satellite group 44 according to the present embodiment, a communication method similar to the communication method of the communication satellite group 44 described in the embodiment can also be applied.

[0082] FIG. 13 is a diagram showing the communication method of the communication satellite group 44 according to the present embodiment. The communication satellite 401 and the user satellite 531 are equipped with a bidirectional communication terminal 65 having a transmission / reception switching device 64. The ground facility 702 operates the transmission / reception switching device 64 based on the data amount α of the command transmitted to the user satellite 531 and the data amount β of the user information data received from the user satellite 531 so that the reception time to transmission time ratio of the user satellite 531 is 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 the present embodiment, mainly, the points added or different from Embodiments 1 and 2 will be described. Note that the same components as those in Embodiments 1 and 2 may be denoted by the same reference numerals, and the description thereof may be omitted.

[0084] <Ground facility> In the present embodiment, the ground facilities used in the satellite monitoring system 500 or the satellite information transmission system 501 described in Embodiments 1 and 2 will be described. Examples of the ground facilities are the ground facility 701 of the monitoring center 53, the ground facility 54 for each infrastructure, or the ground facility 702 that exchanges information with the user satellite 531.

[0085] FIG. 14 is a diagram for explaining the ground facility according to the present embodiment. The ground facilities used in the satellite monitoring system 500 or the satellite information transmission system 501 described in Embodiments 1 and 2 are installed at a latitude of 60° or more and communicate with the "first" of the first satellite 61 once a week.

[0086] The rotation period of the Earth and the revolution period of the orbital plane are different. Therefore, when a communication satellite flying in an orbit with LST 09:00 communicates with ground facilities, for example, ground facilities installed near the equator may only be able to communicate twice, around AM 09:00 and around PM 09:00. On the other hand, for ground facilities installed at high latitudes, even though the rotation period of the Earth and the revolution period of the orbital plane are different, there is an effect that the communication satellite can communicate with the ground facilities every time it orbits the Earth.

[0087] <Example 1 of Communication Satellite> Next, an example 1 of the communication satellite 401 used in the satellite monitoring system 500 or the satellite information transmission system 501 described in Embodiments 1 and 2 will be described.

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

[0089] If there is one set of the first communication device for communicating with ground facilities and three sets of the second communication devices for communicating between infrastructure satellites, it is possible to communicate with communication satellites flying in the same orbital plane and monitoring satellites or user satellites simultaneously. Further, according to the communication satellite according to Example 1 of the communication satellite according to the present embodiment, there is an effect that information communicated with a user satellite can be transmitted to ground facilities in real time. Therefore, even in a situation where the number of satellites flying in the same orbital plane is small during the construction of critical infrastructure, there is an effect that information can be exchanged between user satellites and ground facilities. In addition, since communication terminals can be standardized, there is an effect that the total cost can be reduced.

[0090] <Example 2 of Communication Satellite> Next, an example 2 of a communication satellite used in the satellite monitoring system 500 or the satellite information transmission system 501 described in Embodiments 1 and 2 will be described.

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

[0092] FIG. 17 is a diagram for explaining example 2 of the communication satellite according to the present embodiment. In example 2 of the communication satellite, the communication satellite 401 includes one type of first communication device that communicates with ground facilities, two types of second communication devices that communicate between infrastructure satellites flying before and after the orbital plane, and one type of third communication device that communicates with a monitoring satellite or a user satellite. As a result, there is an effect that information communicated with the user satellite can be transmitted to the ground facilities in real time. Therefore, even in a situation where the number of satellites flying in the same orbital plane is small during the construction of critical infrastructure, there is an effect that information can be exchanged between the user satellite and the ground facilities. Also, by using dedicated terminals for the monitoring satellite or the user satellite, communication is possible even with a small-sized terminal having a small aperture, so there is an effect that the monitoring satellite or the user satellite can be realized as a small satellite.

[0093] Embodiment 4. In the present embodiment, mainly, the points added to or different from Embodiments 1 to 3 will be described. Note that the same reference numerals are given to the same configurations as those in Embodiments 1 to 3, and the description thereof may be omitted.

[0094] In this embodiment, a monitoring system 502 will be described in which the component satellites of the first satellite constellation 810 that monitors the Earth, flying objects, and space objects perform information exchange of satellite information with ground facilities via the component satellites of the second satellite constellation 820.

[0095] <Overall configuration example of the monitoring system 502> FIG. 18 is a diagram showing a configuration example of the monitoring system 502 according to this embodiment. In the monitoring system 502, the component satellites 811 of the first satellite constellation 810 that monitors the Earth, flying objects, and space objects perform information exchange of satellite information with ground facilities via the component satellites 812 of the second satellite constellation 820.

[0096] The first satellite constellation 810 is a satellite group composed of three or more component satellites that cooperate to monitor the Earth, flying objects, and space objects. The ground facilities perform information exchange with the component satellites that make up the first satellite constellation 810. The second satellite constellation 820 is a communication satellite group composed of six or more communication satellites that fly in a sun-synchronous orbit with an orbital altitude of 800 km or more in a substantially evenly distributed manner and communicate with satellites flying before and after in the same orbital plane, and cooperate to relay satellite information. That is, the component satellites of the second satellite constellation 820 are a communication satellite group composed of six or more communication satellites.

[0097] The component satellites that make up the first satellite constellation 810 perform information exchange with ground facilities via the second satellite constellation 820.

[0098] In recent years, with the emergence of flying objects that glide at supersonic speeds, satellite launches and flight path tracking are expected. However, it may be difficult to establish a constant communication environment in a LEO constellation.

[0099] There is also a technology for exchanging information via data relay satellites in geostationary orbit. However, when the number of satellites in orbit increases and the utilization frequency of data relay satellites increases, there may be cases where communication lines cannot be used in emergencies. In addition, since information is transmitted from LEO satellites to ground facilities via geostationary orbit, there may be a time delay.

[0100] In the monitoring system 502 according to the present embodiment, information exchange between the first satellite constellation and ground facilities can be always communicable via a group of communication satellites configured in a low-altitude sun-synchronous orbit. In addition, there is an effect that information can be exchanged in a shorter time than via data relay satellites in geostationary orbit.

[0101] Also, by increasing the number of satellites in the second satellite constellation, the number of satellites in the first satellite constellation configuration that can exchange data simultaneously can be increased. Therefore, there is an effect that monitoring data of a large number of monitoring targets can be exchanged simultaneously. Also, by increasing the number of satellites in the second satellite constellation, the number of ground facilities that can exchange data simultaneously can be increased. Therefore, there is an effect that response actions for a large number of monitoring targets can be taken simultaneously.

[0102] In addition, when a sun-synchronous orbit satellite is adopted to monitor the Earth, flying objects or space objects with a visible high-resolution optical monitoring device, there is a problem that the time for information exchange with ground facilities installed at a specific longitude is limited. The same problem existed even when a geostationary data relay satellite was adopted. In the monitoring system 502 according to the present embodiment, by realizing an always-on communication environment via a group of low-orbit communication satellites, there is an effect that it can be used for emergency response in the event of a disaster or the like.

[0103] Satellites over the equator generally use a geostationary orbit, but there is a problem that it is difficult to perform high-resolution monitoring with geostationary satellites flying at an altitude of 36,000 km. Therefore, if an orbit that makes multiple revolutions around the equator in one day is adopted, there is an effect that high-resolution monitoring becomes possible. However, even in this case, there is a problem that continuous communication cannot be achieved only with ground facilities installed at a specific longitude. Therefore, there is an effect that a group of satellites orbiting over the equator capable of continuous communication can be realized.

[0104] <Example 1 of the First Satellite Constellation 810> Example 1 of the first satellite constellation 810 is a satellite constellation that makes multiple revolutions around an inclined circular orbit with an orbital altitude of 1,000 km or more and 6,000 km or less in one day. The multiple orbital planes formed by the multiple component satellites included in the first satellite constellation 810 are shifted by equal angles in the azimuth direction of their normal vectors to each other, and the flight positions of each orbital plane are synchronously controlled.

[0105] FIG. 19 is a configuration example of Example 1 of the first satellite constellation 810 according to the present embodiment. Let the number of times each component satellite orbits the Earth in one day be "N". The first satellite constellation 810 includes N component satellites. Each component satellite moves in an inclined circular orbit and orbits the Earth N times in one day. The plane formed by the orbit in which each component satellite moves is called an orbital plane. The N orbital planes formed by the N component satellites are shifted by 360 / N degrees in the azimuth direction of their normal vectors to each other. In other words, the relative angle of the azimuth component is shifted by 360 / N degrees. The azimuth direction corresponds to the traveling direction of the component satellite. That is, the azimuth direction corresponds to the longitude direction and the east-west direction.

[0106] Specifically, the first satellite constellation 810 includes eight component satellites (A to H) and forms eight orbital planes. Each component satellite orbits the Earth eight times in one day. The normal vectors of each of the eight orbital planes are shifted by 45 degrees in the relative angle of the azimuth component to each other.

[0107] The timing at which the component satellites (A to H) of the N satellites pass through the northernmost points of their respective orbital planes is synchronized. That is, the component satellites (A to H) of the N satellites pass through the northernmost points of their respective orbital planes 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 plurality of orbital planes formed by the plurality of component satellites included in the first satellite constellation 810 are shifted by equal angles in the azimuth direction component of their respective major axes.

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

[0110] The three component satellites (A to C) alternately monitor the target area of the Earth from the perigee, apogee, or midpoint. The midpoint is a point located between the perigee and the apogee. At the perigee, monitoring can be performed with high resolution although it is for a short time. At the apogee, monitoring can be performed for a long time although the resolution is low.

[0111] The major axes of each of the three elliptical orbits are inclined at equal intervals of about 120° with respect to the circumferential direction of the orbital plane. The azimuth direction corresponds to the longitude direction, that is, the east-west direction. The major axis of each elliptical orbit rotates with respect to the sun 102, but the relative relationship of the three elliptical orbits is maintained.

[0112] <Example 3 of the First Satellite Constellation 810> In Example 3 of the first satellite constellation 810, the orbit above the equator is orbited multiple times a day, and the flying positions are synchronously controlled with the azimuth direction components shifted by equal angles. In Example 1 of the first satellite constellation 810 in FIG. 19, each constituent satellite moves in an inclined circular orbit and orbits the Earth N times a day. On the other hand, in Example 3 of the first satellite constellation 810, each constituent satellite moves in an orbit above the equator and orbits the Earth N times a day. Each constituent satellite moves in an inclined circular orbit and orbits the Earth N times a day. And the orbital planes in which each constituent satellite moves have their flying positions synchronously controlled with the azimuth direction components shifted by equal angles.

[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 that make up the first satellite constellation 810, and a third satellite 63 that only performs communication with satellites flying before and after.

[0114] <Example 5 of the Second Satellite Constellation> Example 5 of the second satellite constellation 820 is a sun-synchronous orbit, and a group of six or more communication satellites flying in each orbital plane between LST09:00 and LST15:00 cooperate to relay satellite information.

[0115] Sun-synchronous orbits are frequently used in Earth observation satellites. In optical satellites, the vicinity of LST10:30 and LST13:30 with good sunlight conditions is frequently used. Also, in radar satellites, LST06:00 and LST18:00, which are advantageous for solar power generation, are frequently used. When the orbital altitude of the communication satellite is 881 km, the inscribed circle of a regular octagon is 6727 km, so a communication line with any monitoring satellite of LST can be secured. Note that the monitoring satellite may be a user satellite that uses the communication satellite group 44 as a communication line. Therefore, as shown in Fig. 18, if the constituent satellites of the second satellite constellation 820 are deployed on two orbital planes of LST09:00 and LST15:00, there is an effect that communication can be made with all of the satellite groups frequently used for earth observation.

[0116] ***Other configurations*** The ground facility of the monitoring system 502 according to the present embodiment may be a moving object. For example, when detecting the launch of a flying object that glides at supersonic speed, it is reasonable to transmit information to a moving object such as an aircraft, UAV (unmanned aerial vehicle), ship, or vehicle that takes direct countermeasures in terms of implementing countermeasures in a short time.

[0117] Embodiment 5. In the present embodiment, mainly, the points added to or different from Embodiments 1 to 4 will be described. Note that the same components as those in Embodiments 1 to 4 may be denoted by the same reference numerals, and the description thereof may be omitted. In the present embodiment, mainly, the communication method of the satellite information transmission system 501 will be described.

[0118] <Example 1 of the communication method of the satellite information transmission system 501> Fig. 22 is a diagram showing a configuration example of the satellite information transmission system 501 according to the present embodiment. Fig. 23 is a diagram showing an overall configuration example of the satellite information transmission system 501 according to the present embodiment. The satellite information transmission system 501 according to the present embodiment relays satellite information between the user satellite 531 that constitutes a user satellite group orbiting the earth and the ground facility 702. The satellite information transmission system 501 includes a communication satellite group 44 consisting of six or more communication satellites that orbit a sun-synchronous orbit in a low Earth orbit (LEO) with an orbital altitude of 500 km or more and 2000 km or less in a substantially uniform arrangement and communicate with communication satellites flying before and after on the same orbital plane. The communication satellite 401 communicates with communication satellites flying before and after.

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

[0120] Optical communication has the advantage of enabling high-capacity data transmission. However, since it is necessary to align the optical axes accurately between satellites, both the user satellite and the communication satellite need to perform two-axis high-precision pointing control. Since the relative position relationship between the ground facilities and the communication satellite varies greatly, it is necessary to perform real-time high-precision control of the pointing direction that changes every moment. Also, when the relative position relationship between the user satellite and the communication satellite varies greatly, it is similarly necessary to perform real-time high-precision control of the pointing direction that changes every moment. When the relative position variation is large, the communication available time is also limited, so it is necessary to perform high-capacity communication.

[0121] If one satellite simultaneously realizes all optical communication between the communication satellites before and after, with the user satellite, and with the ground facilities, it is necessary to simultaneously perform high-precision optical axis alignment with different targets. This has the problems of high technical difficulty and a high risk of communication interruption. In radio wave communication, when achieving long-distance high-speed large-capacity data transmission, it is necessary to align the central axis of the main beam of the radio wave with high precision, similar to the above-mentioned optical communication. However, in short-range communication, low-speed communication, or communication with limited data volume, communication without high-precision axis alignment is also possible using a fixed antenna or an omnidirectional antenna.

[0122] In the communication before and after the communication satellite group according to the above-described embodiment, since the satellite-to-satellite distance is limited and the relative angle fluctuation between the front and rear satellites is small, it is not optical communication or high-speed large-capacity radio wave communication that requires high-precision pointing control, but radio wave communication using a fixed antenna is also achievable. Furthermore, since communication is always possible, there is an effect that even in low-speed communication, large-capacity communication can be achieved over time. If radio wave communication that does not require high-precision pointing control is realized between the front and rear satellites, whether the first satellite performs optical communication with ground facilities or the third satellite performs optical communication with a user satellite, the number of communication targets that require high-precision pointing control simultaneously is limited to one. Therefore, there is an effect that the pointing control is easy and the risk of communication interruption can be sufficiently reduced.

[0123] <Example 2 of the communication method of the satellite information transmission system 501> In Example 2 of the communication method of the satellite information transmission system 501, the radio waves between the communication satellites flying in the front and rear are spread in spectrum. When the front and rear satellites flying in the same orbit perform radio wave communication, there is a problem that there is a risk of radio wave interference or mistransmission among a plurality of satellites flying in the front or rear. By spreading the spectrum and restoring only the desired satellite signal, there is an effect that radio wave interference or mistransmission can be avoided.

[0124] <Example 3 of the communication method of the satellite information transmission system 501> In Example 3 of the communication method of the satellite information transmission system 501, the communication satellite includes a bidirectional communication terminal 65 with a transmission / reception switching function for communicating with the communication satellites flying in the front and rear. If a communication satellite is equipped with a transmission terminal to a front satellite and a reception terminal from a rear satellite, and all satellites communicate with the front and rear satellites in the same orbit, it constitutes a satellite information transmission system. However, there is a problem that the risk of communication interruption is high during the maintenance stage of launching a satellite into orbit or when a failure occurs in orbit. If it is equipped with a two-way communication terminal 65 with a transmission / reception switching function, there is an effect that satellite information transmission becomes possible even if not all satellites are in place in orbit.

[0125] <Example 4 of the communication method of the satellite information transmission system 501> In Example 4 of the communication method of the satellite information transmission system 501, the communication satellite adopts different polarization waves for transmission and reception. Since the relative position and relative attitude with the front and rear communication satellites are maintained, by adopting different polarization waves for transmission and reception, there is an effect that the risk of radio wave interference or mistransmission can be eliminated.

[0126] <Example 5 of the communication method of the satellite information transmission system 501> In Example 5 of the communication method of the satellite information transmission system 501, the communication satellite group 44 is equipped with a fourth satellite that performs optical communication with ground facilities and also performs optical communication with user satellites. Regarding satellite information with urgency, if one satellite simultaneously conducts information exchange between the user satellite and the ground facility, there is an effect that the delay time can be minimized. Since it is necessary to perform high-precision pointing control for two targets simultaneously, the technical difficulty is high and it becomes a high-cost system. However, if the communication with the front and rear satellites is also optical communication, compared with the case of performing high-precision pointing control for four different targets, it is easier to implement at each stage and there is an effect that it becomes low-cost. Also, when there is no urgency, since the flight positions where the user satellite and the ground facility can communicate simultaneously are limited, if one satellite is equipped with communication functions for both parties and communicates in a time-division manner, the target for simultaneous high-precision pointing control can be limited to one.

[0127] <Example 6 of the communication method of the satellite information transmission system 501> FIG. 24 is a diagram showing Communication Method Example 6 of the satellite information transmission system 501 according to the present embodiment. The fourth satellite 644 shares the optical communication with the ground facility 702 and the optical communication with the user satellite 531 using the same optical communication terminal 544. The fourth satellite 644 rotates around the satellite traveling direction axis and performs the optical communication with the ground facility 702 and the optical communication with the user satellite 531 in a time-division manner.

[0128] When there is no urgency, since the flying positions where the user satellite and the ground facility can communicate simultaneously are limited, if one satellite has the communication function with both and communicates in a time-division manner, the object to be controlled with high-precision orientation simultaneously can be limited to one. Furthermore, standardizing the communication terminals with the user satellite and the ground facility has the effect of cost reduction. This is effective when a sufficient number of communication satellites are flying in orbit and do not deviate from the radio wave field of view even when rotating around the traveling direction axis.

[0129] ***Other configurations*** The ground facility 702 according to the present embodiment may be a moving body. Regarding satellite information having urgency, when it is necessary to transmit from a fixed ground facility to a moving body, there is an effect that the satellite information transmission from the communication satellite directly to the moving body can suppress the delay time to a minimum. This is effective in cases where a time delay in seconds, such as instructing a countermeasure action after detecting the launch of a flying object, may lead to an increase in risk.

[0130] Also, the communication satellite group 44 may include a first satellite 61 that performs radio wave communication with the ground facility 702, a second satellite 62 that performs optical communication with the user satellite 531, and a third satellite 63 that only performs communication with communication satellites flying before and after. And the communication satellite group 44 performs radio wave communication between communication satellites flying before and after. In the optical communication between a communication satellite and a ground facility, there is a problem that communication cannot be performed when there are clouds. For this reason, when the ground facility 701 using the satellite information transmission system of Communication Method Example 1 is in an area with a high cloud cover rate, there is an effect that the availability is improved by using radio wave communication.

[0131] Embodiment 6 In this embodiment, mainly, the points added to or different from Embodiments 1 to 5 will be described. Note that the same components as those in Embodiments 1 to 5 may be denoted by the same reference numerals, and the description thereof may be omitted. In this embodiment, mainly, the configurations of a communication satellite constellation, a satellite constellation, and a satellite information transmission system using the satellite flying in the sun-synchronous orbit described in Embodiments 1 to 5 will be described.

[0132] <Configuration of artificial satellite 80> FIG. 25 is a diagram showing a configuration example of the artificial satellite 80 according to this embodiment. The artificial satellite 80 according to this embodiment 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 81. 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 directed toward the sunlight incident side and a heat dissipation surface of the information processing device 81 on the side opposite to the sunlight incident side. The artificial satellite 80 has a solar cell directed toward the sunlight incident side and, on the side opposite to the sunlight incident side, for example, a heat dissipation surface of a computer or an edge server.

[0133] The sun-synchronous orbit is a kind of polar orbit that passes over the polar regions. The sun-synchronous orbit has a rotation period around the north-south axis of the orbital plane synchronized with the revolution period of the Earth. Therefore, in the sun-synchronous orbit, the incident angle of the sun with respect to the orbital plane remains constant throughout the year. Also, in the orbit at LST06:00 or LST18:00, since the normal vector of the orbital plane is directed toward the sun, even a low-earth orbit satellite is constantly irradiated with sunlight without being in the Earth's shadow. Strictly speaking, due to the inclination of the Earth's axis, the normal vector is inclined from the sun direction, but the influence is minor.

[0134] The computers and servers that play the role of the brain in the surveillance satellite are becoming more power-hungry with the advent of AI and the increase in server capacity and speed, and heat dissipation measures are a problem for high-heat-generating devices. LST06:00 or LST18:00 in the sun-synchronous orbit is also called the dawn-dusk orbit. This dawn-dusk orbit is a low-earth orbit satellite that does not enter the earth's shadow and can always generate electricity with solar cells. Furthermore, since the dawn-dusk orbit always points to deep space on the opposite side of the sun incidence, it is an orbit with excellent heat dissipation performance by radiative cooling. Therefore, in the dawn-dusk orbit, there is an effect that a large amount of power can be secured and heat can be dissipated 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 large-scale and high-speed development of cloud computing, the issues of increased power consumption and heat dissipation measures for high-heat-generating devices also arise in the cloud environment of the ground system. Therefore, by regarding the artificial satellite 80 equipped with an edge server as an IoT and performing distributed computing, there is an effect that the load on the ground system can be reduced and contributions can be made to the SDGs. Furthermore, by equipping the artificial satellite 80 with a supercomputer or a cloud server and installing a centralized computing device in space, there is an effect that the load on the ground system can be reduced and contributions can be made to the SDGs. IoT is an abbreviation for Internet of Things. SDGs is an abbreviation for Sustainable Development Goals.

[0136] <Configuration example of communication satellite constellation 801> FIG. 26 is a diagram showing a configuration example of a communication satellite constellation 801 according to the present embodiment. The communication satellite constellation 801 is a satellite constellation flying in a sun-synchronous orbit of LST06:00 or LST18:00. The communication satellite constellation 801 includes communication satellites equipped with communication devices with the ground. The communication satellite is an example of the artificial satellite 80. In addition, the communication satellite constellation 801 includes a communication device for communication between communication satellites flying before and after in the same orbital plane, forming an annular communication network.

[0137] According to the communication satellite constellation 801, in the communication satellite, since it can always generate electricity with a fixed solar cell, there is an effect that the communication satellite can be realized at low cost.

[0138] <Configuration example of satellite constellation 802> FIG. 27 is a diagram showing a configuration example of the satellite constellation 802 according to the present embodiment. In FIG. 27, in the satellite constellation 802, the satellite is equipped with an edge server. The satellite constellation 802 flies in a sun-synchronous orbit at LST06:00 or LST18:00. The satellite constellation 802 includes satellites. The satellite is an example of the artificial satellite 80.

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

[0140] The satellite constellation 802 includes a communication device for communication between satellites flying before and after in the same orbital plane, forming an annular communication network. That is, the satellites constituting the satellite constellation 802 include a communication device for communication between satellites flying before and after in the same orbital plane, forming an annular communication network.

[0141] The sun-synchronous orbit passes through the polar regions once a week. Therefore, according to the satellite constellation 802, all satellites can always communicate with the ground data center installed in the high-latitude zone via the annular communication network.

[0142] FIG. 28 is a diagram showing another example of the configuration of the satellite constellation 802 according to the present embodiment. In FIG. 28, the satellite constellation 802 is composed of a communication satellite, a satellite equipped with a supercomputer, and a satellite equipped with a cloud server. According to the satellite constellation 802 of FIG. 28, since the results of analysis processing on the orbit can be delivered to ground users, there is an effect of reducing the burden on the ground system.

[0143] <Configuration example of Example 1 of the satellite information transmission system 503> FIG. 29 is a diagram showing a configuration example of Example 1 of the satellite information transmission system 503 according to the present embodiment. In FIG. 29, the state of viewing the satellite information transmission system 503 from the direction of the sun is shown.

[0144] Example 1 of the satellite information transmission system 503 is composed of a user satellite group, a communication satellite group, and ground facilities. The user satellite group consists of user satellites flying in a low Earth orbit (LEO) with an orbital altitude of 500 km or more and 2000 km or less. The communication satellite group consists of a plurality of communication satellites flying in a sun-synchronous orbit at LST 06:00 or LST 18:00. Each satellite of the communication satellite group is an example of the artificial satellite 80.

[0145] The communication satellite group includes a first satellite that communicates with the ground facilities and a second satellite that communicates with the user satellites. The communication satellite group communicates with the communication satellites flying before and after. The user satellites and the ground facilities exchange information via the communication satellite group.

[0146] For satellites in sun-synchronous orbits, due to the effect of the Earth's rotation, communication with ground facilities is possible only in the same time zone from the low-latitude zone to the mid-latitude zone. On the other hand, as long as a view can be secured over the polar regions, communication with ground facilities is possible at all times without being limited by the time zone of LST. Therefore, if satellites communicate with the preceding and following satellites to form an annular communication network, and a satellite passing near the poles communicates with the ground facilities on behalf of others, communication with ground facilities can be achieved at all times.

[0147] The user satellite constitutes a flying object tracking system responsible for detecting and tracking the launch of flying objects. Information from the user satellite needs to be transferred quickly in case of an emergency. According to Example 1 of the satellite information transmission system 503, there is an effect that satellite information can be quickly transmitted to ground facilities installed in the high-latitude zone via an annular communication network. Note that the user satellites constituting the flying object tracking system include surveillance satellites equipped with infrared detection devices and a group of communication satellites formed in inclined orbits.

[0148] <Configuration example of Example 2 of the satellite information transmission system 503> FIG. 30 is a diagram showing a configuration example of Example 2 of the satellite information transmission system 503 according to the present embodiment. In FIG. 30, the state of viewing the satellite information transmission system 503 from the North Pole is shown.

[0149] Example 2 of the satellite information transmission system 503 is composed of a first communication constellation 831, a second communication constellation 832, and ground facilities.

[0150] The first communication constellation 831 flies in an orbit over the equator. Also, the first communication constellation 831 is composed of a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network. The second communication constellation 832 flies in a sun-synchronous orbit. Also, the second communication constellation 832 is composed of a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network.

[0151] Each satellite of the first communication constellation 831 and the second communication constellation 832 includes a second communication device through which the first communication constellation 831 and the second communication constellation 832 communicate with each other. 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 communication constellation and the second communication constellation may include a communication device for communicating with a user satellite. The user satellite may transmit satellite information to ground facilities via the first communication constellation 831 and the 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 from the mid-latitude zone to the high-latitude zone. In such cases, it is reasonable for an equatorial satellite that forms an annular communication network in the longitudinal direction and a sun-synchronous satellite that forms an annular communication network in the latitudinal direction to communicate with each other. If there are ground facilities in the high-latitude zone where the sun-synchronous satellite can secure a communication field of view when passing over the polar region, there is an effect that the satellite information acquired by the equatorial satellite can be transmitted to the ground facilities almost in real time with only one orbital plane of the sun-synchronous satellite. Needless to say, the first communication constellation and the second communication constellation may each include a communication device for communicating with a user satellite.

[0154] <Configuration example of Example 3 of the satellite information transmission system 503> FIG. 31 is a diagram showing a configuration example of Example 3 of the satellite information transmission system 503 according to the present embodiment. In FIG. 31, a state of viewing the satellite information transmission system 503 from the North Pole is shown.

[0155] Example 3 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. Also, the first communication constellation 831 is formed by a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network. The second communication constellation 832 flies in a sun-synchronous orbit. Also, the second communication constellation 832 is formed by a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network. The third communication constellation 833 flies in an inclined orbit. Also, the third communication constellation 833 is formed by a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network.

[0157] Each satellite of the first communication constellation 831, the second communication constellation 832, and the third communication constellation 833 is equipped with a second communication device. The second communication device is a communication device for the first communication constellation and the second communication constellation, or the second communication constellation and the third communication constellation, or the third communication constellation and the first communication constellation to communicate.

[0158] Each satellite of the first communication constellation 831, the second communication constellation 832, and the third communication constellation 833 transmits satellite information to the ground facilities 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 communication constellation, the second communication constellation, and the third communication constellation 833 may be equipped with a communication device for communicating with the user satellite. The user satellite may transmit satellite information to the ground facility via at least two of the first communication constellation 831, the second communication constellation 832, and the third communication constellation 833.

[0160] There may be a case where satellite information acquired by an equatorial orbit satellite is transmitted to a ground facility installed in the mid-latitude zone. In such a case, it is reasonable for an inclined orbit satellite forming an annular communication network in an inclined orbit flying in the longitudinal direction in the mid-latitude zone, an equatorial satellite forming an annular communication network in the longitudinal direction, and a sun-synchronous satellite forming an annular communication network in the latitudinal direction to communicate with each other.

[0161] For example, when the ground facility is installed at 35 degrees north latitude, an inclined orbit satellite with an orbital inclination angle of 35 degrees flies in the longitudinal direction over the ground facility, so that the communication time with the ground facility can be ensured for a long time. If an inclined orbit satellite group having a plurality of orbital planes with normal vectors dispersed in the longitudinal direction is provided as the inclined orbit satellite group, there is an effect that satellite information acquired by an equatorial satellite can be transmitted to the ground facility almost in real time.

[0162] <Configuration example of Example 4 of satellite information transmission system 503> FIG. 32 is a diagram showing a configuration example of Example 4 of the satellite information transmission system 503 according to the present embodiment. In FIG. 32, a state of viewing the satellite information transmission system 503 from the North Pole is shown.

[0163] Example 4 of the satellite information transmission system 503 is composed of a first communication constellation 831a, a second communication constellation 832, and a ground facility.

[0164] The first communication constellation 831a flies in a sun-synchronous orbit. Also, in the first communication constellation 831a, a plurality of satellites each having a first communication device for communicating with satellites before and after in the traveling direction on the same orbital plane form an annular communication network. The second communication constellation 832 flies in a sun-synchronous orbit with a different LST from that of the first communication constellation 831a. Also, in the second communication constellation 832, a plurality of satellites each having a first communication device for communicating with satellites before and after in the traveling direction on the same orbital plane form an annular communication network.

[0165] Each satellite of the first communication constellation 831a and the second communication constellation 832 is equipped with a second communication device for communicating when the first communication constellation 831a and the second communication constellation 832 pass near the polar region. Each satellite of 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] The sun-synchronous satellite becomes a polar-orbiting satellite that passes near the upper airspace of the polar region. Therefore, the first communication constellation 831a and the second communication constellation 832 that form an annular communication network include satellites that can communicate near the upper airspace of the polar region. By transmitting satellite information to the annular communication networks of communication constellations with different LSTs, there is an effect that satellite information can be transmitted at a desired time zone regardless of the latitude zone where the ground facilities are installed.

[0167] <Configuration example of Example 5 of satellite information transmission system 503> FIG. 33 is a diagram showing a configuration example of Example 5 of the satellite information transmission system 503 according to the present embodiment. In FIG. 33, a state of viewing the satellite information transmission system 503 from above the equator is shown.

[0168] Example 5 of the satellite information transmission system 503 is composed of a first communication constellation 831, a second communication constellation 832a, and ground facilities.

[0169] The first communication constellation 831 flies in an equatorial orbit. Also, the first communication constellation 831 is formed by a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network. The second communication constellation 832a flies in an inclined orbit. Also, the second communication constellation 832a is formed by a plurality of satellites equipped with a first communication device that communicates with satellites before and after in the traveling direction on the same orbital plane to form an annular communication network.

[0170] Each satellite of the first communication constellation 831 and the second communication constellation 832a is equipped with a second communication device through which the first communication constellation 831 and the second communication constellation 832a communicate. Each satellite of the first communication constellation 831 and the second communication constellation 832a transmits satellite information to the ground facilities via the first communication constellation 831 and the second communication constellation 832a.

[0171] According to Example 5 of the satellite information transmission system 503, there is an effect that satellite information acquired by a satellite in an equatorial orbit can be transmitted to ground facilities installed in the mid-latitude zone. Also, the time zone when the second communication constellation 832a flies over the ground facilities is known in advance from the planned orbit information. Therefore, there is an effect that satellite information can be transmitted to the ground facilities at a desired time zone when the second communication constellation 832a is composed of a plurality of orbital planes with different normal vectors.

[0172] As described in Embodiment 1, the satellite is controlled by commands transmitted from ground facilities. The ground facilities include a satellite constellation forming unit in a processor that forms a satellite constellation by communicating with each satellite. Also, the satellite side is equipped with a satellite constellation forming unit, and the satellite constellation forming units of each of the plurality of satellites cooperate with the satellite constellation forming unit provided in the ground facilities to realize the control of the satellite constellation. Note that the satellite constellation forming unit of the satellite is provided, for example, in a satellite control device.

[0173] In the above Embodiments 1 to 6, each part of each system and each device such as a satellite monitoring system, a satellite information transmission system, ground facilities, a communication satellite, a monitoring system, a constituent satellite, a communication satellite constellation, a satellite constellation, an artificial satellite, and a satellite have been described as independent functional blocks. However, the configuration of each system and each device does not have to be the configuration as in the above-described embodiments. As long as the functional blocks of each system and each device can realize the functions described in the above-described embodiments, any configuration may be used. Also, each system and each device may be a single device or a system composed of a plurality of devices. Also, among Embodiments 1 to 6, a plurality of parts or examples may be combined and implemented. Alternatively, one part or example among these embodiments may be implemented. Additionally, these embodiments may be combined and implemented in any way, either as a whole or partially. That is, in Embodiments 1 to 6, free combinations of each embodiment, modifications of any constituent elements of each embodiment, or omissions of any constituent elements in each embodiment are possible.

[0174] Note that the above-described embodiments are essentially preferred examples and are not intended to limit the scope of the present disclosure, the scope of the applications of the present disclosure, and the scope of the uses of the present disclosure. The above-described embodiments can be variously modified as necessary.

Description 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 Device, 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 Meteorological Satellite, 404 Observation Satellite, 405 First Observation and Monitoring Satellite, 406 Positioning Satellite, 407 Second Observation and Monitoring Satellite, 408 Space Base, 409 Lunar and Planetary Exploration Satellite, 410 Exploration Satellite, 411 Transporter, 421 Optical Surveillance Satellite, 422 Infrared Surveillance Satellite, 423 Radio Surveillance Satellite, 424 Service Satellite, 425 Debris Removal Satellite, 51 Critical Infrastructure, 510 Infrastructure Satellite Group, 511 Infrastructure Satellite, 52 Surveillance Satellite Group, 521, 521a, 521b, 521c Surveillance Satellite, 53 Surveillance Center, 54 Ground Facility for Each Infrastructure, 530 User Satellite Group, 531 User Satellite, 542 Radio Communication Terminal, 544 Optical Communication Terminal, 590 Surveillance Information, 61 First Satellite, 62 Second Satellite, 63 Third Satellite, 644 Fourth Satellite, 64 Transmission / Reception Switching Device, 65 Bidirectional Communication Terminal, 601 First Satellite Group, 602 Second Satellite Group, 603 Third Satellite Group, 500 Satellite Surveillance System, 501, 503 Satellite Information Transmission System, 502 Monitoring System, 701, 702 Ground Facility, 710 Surveillance Management Department, 720 Storage Unit, 80 Artificial Satellite, 81 Information Processing Device, 801 Communication Satellite Constellation, 802 Satellite Constellation, 810 First Satellite Constellation, 811, 812 Constituent Satellite, 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 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. A ground facility included in a monitoring system comprising: The satellites constituting the first satellite constellation include: Transmitting and receiving information with the ground facility 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: The normals of each satellite are offset by equal angles in the azimuth direction, and the flight positions of each orbital plane are synchronously controlled. The ground equipment includes: A ground facility that transmits information via the first satellite constellation and the second satellite constellation and controls satellites that constitute each of the first satellite constellation and the second satellite constellation by commands.

2. 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 ground facility included in 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: Send and receive information via the communications satellites; The ground equipment includes: A ground facility that performs optical communication with the first satellite, and performs radio communication with the first satellite when the area has a cloud coverage rate higher than a predetermined value.

3. a first communication constellation in which a plurality of satellites, each of which has a first communication device that flies in an equatorial orbit and communicates with satellites in front of and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; a second communication constellation in which a plurality of satellites, each of which has a first communication device that flies in a sun-synchronous orbit and communicates with satellites in front of and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; Ground facilities and A ground facility included in a satellite information transmission system comprising: Each satellite of the first communications constellation and the second communications constellation comprises: a second communication device that communicates with the first communication constellation and the second communication constellation, and transmits satellite information to a ground facility via the first communication constellation and the second communication constellation; The ground equipment includes: A ground facility that transmits information via the first communication constellation and the second communication constellation so that the first communication constellation and the second communication constellation each form a circular communication network, and controls satellites that constitute each of the first communication constellation and the second communication constellation by commands.

4. a first communication constellation in which a plurality of satellites, each of which has a first communication device that flies in an equatorial orbit and communicates with satellites in front of and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; a second communication constellation in which a plurality of satellites, each of which has a first communication device that flies in a sun-synchronous orbit and communicates with satellites in front of and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; a third communication constellation in which a plurality of satellites, each of which has a first communication device that flies in an inclined orbit and communicates with satellites in front and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; Ground facilities and A ground facility included in a satellite information transmission system comprising: Each satellite of the first communications constellation, the second communications constellation, and the third communications constellation comprises: a second communication device in which the first communication constellation and the second communication constellation, or the second communication constellation and the third communication constellation, or the third communication constellation and the first communication constellation communicate with each other, and the second communication device transmits satellite information to a ground facility via at least two of the first communication constellation, the second communication constellation, and the third communication constellation; The ground equipment includes: A ground facility that transmits information via at least two of the first communication constellation, the second communication constellation, and the third communication constellation, and controls satellites that constitute each of the first communication constellation and the second communication constellation by commands, so that the first communication constellation, the second communication constellation, and the third communication constellation each form a circular communication network.

5. a first communication constellation in which a plurality of satellites, each of which has a first communication device that flies in a sun-synchronous orbit and communicates with satellites in front of and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; a second communication constellation in which a plurality of satellites, each of which has a first communication device that flies in a sun-synchronous orbit in a local sun time (LST) different from that of the first communication constellation and communicates with satellites in front and behind the first communication constellation in the same orbital plane, form a circular communication network; Ground facilities and A ground facility included in a satellite information transmission system comprising: Each satellite of the first communications constellation and the second communications constellation comprises: a second communication device that communicates with the first communication constellation and the second communication constellation when the first communication constellation and the second communication constellation pass near a polar region; Transmitting satellite information to a ground facility via the first communication constellation and the second communication constellation; The ground equipment includes: A ground facility that transmits information via the first communication constellation and the second communication constellation so that the first communication constellation and the second communication constellation each form a circular communication network, and controls satellites that constitute each of the first communication constellation and the second communication constellation by commands.

6. a first communication constellation in which a plurality of satellites, each of which has a first communication device that flies in an equatorial orbit and communicates with satellites in front of and behind the satellite in the same orbital plane in the direction of travel, form a circular communication network; a second communication constellation in which a plurality of satellites, each of which has a first communication device that flies in an inclined orbit and communicates with satellites in front and behind the satellite in the same orbital plane in the direction of flight, form a circular communication network; Ground facilities and A ground facility used in a satellite information transmission system comprising: Each satellite of the first communications constellation and the second communications constellation comprises: a second communication device that communicates with the first communication constellation and the second communication constellation, and transmits satellite information to a ground facility via the first communication constellation and the second communication constellation; The ground equipment includes: A ground facility that transmits information via the first communication constellation and the second communication constellation so that the first communication constellation and the second communication constellation each form a circular communication network, and controls satellites that constitute each of the first communication constellation and the second communication constellation by commands.

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