Satellite monitoring system and satellite information transmission system

Abstract

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

Description

Technical Field

[0001] The present disclosure relates to ground facilities, 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 essential 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, dangerous events accompanied by the risk of failure or loss of critical infrastructure are increasing. Therefore, a mechanism is needed 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 satellite constellations orbiting the Earth (LEO), a challenge exists in that if an emergency situation occurs and infrastructure satellites are orbiting on the opposite side of the Earth, communication with the monitoring center cannot be secured. Note that Earth orbit refers to orbits with altitudes between 500 km and 2000 km. LEO is an abbreviation for Low Earth Orbit. Patent Document 1 does not disclose a method for monitoring critical infrastructure in Earth orbit.

[0006] This disclosure aims to ensure a communication environment between monitoring satellites and monitoring centers in a constellation of satellites orbiting the Earth, and to enable the exchange of information between user satellites and ground equipment. [Means for solving the problem]

[0007] Regarding this disclosure Critical infrastructure, which is social infrastructure in outer space, is composed of a constellation of infrastructure satellites that orbit the Earth at an altitude of 500 km to 2000 km (LEO: Low Earth Orbit), A constellation of monitoring satellites consisting of monitoring satellites that fly in orbits at an altitude of 2000 km or less to monitor the aforementioned infrastructure satellite constellation and perform on-orbit services, Ground equipment installed on the ground and used to exchange information with each of the infrastructure satellites in the aforementioned infrastructure satellite constellation, A monitoring center installed on the ground and which exchanges information with the aforementioned monitoring satellite. Equipped with, The aforementioned infrastructure satellite constellation includes a constellation of communication satellites, The aforementioned group of communications satellites is They fly in evenly spaced orbits with orbital altitudes and inclinations that result in sun-synchronous orbits that complete an integer number of orbits per day. The aforementioned communications satellite, It communicates with communication satellites flying in front of and behind it. The aforementioned group of communications satellites is A first satellite that communicates with the aforementioned ground facilities, A second satellite that communicates with the aforementioned monitoring satellite, A third satellite that will only communicate with the communication satellites flying in front of and behind it. Equipped with, The aforementioned monitoring satellite and the aforementioned monitoring center are, A communications satellite used in a satellite monitoring system that performs information exchange via the aforementioned group of communications satellites, A first communication device that communicates with the aforementioned ground equipment, Three second communication devices that communicate with the aforementioned infrastructure satellites and It is equipped with, It communicates simultaneously with communication satellites orbiting in the same orbital plane, as well as with monitoring satellites or user satellites. [Effects of the Invention]

[0008] The communications satellite described in this disclosure can transmit information communicated with the user satellite to ground facilities in real time. Therefore, the communications satellite described in this disclosure has the effect of enabling information exchange between the user satellite and ground facilities even when there are few satellites orbiting in the same orbital plane during the construction of critical infrastructure. [Brief explanation of the drawing]

[0009] [Figure 1] A diagram showing an example of the overall configuration of the satellite monitoring system according to Embodiment 1. [Figure 2] A diagram showing an example configuration of a monitoring center according to Embodiment 1. [Figure 3] A diagram showing an example of the configuration of a satellite, which is an example of a space object according to Embodiment 1. [Figure 4] A diagram showing an example configuration of a communications satellite according to Embodiment 1. [Figure 5] A diagram showing an example configuration of an observation satellite according to Embodiment 1. [Figure 6] A diagram showing another example of the configuration of the observation satellite according to Embodiment 1. [Figure 7]Diagram showing a configuration example of the satellite monitoring system according to Embodiment 1. [Figure 8] Diagram showing a configuration example 3 of the communication satellite group according to Embodiment 1. [Figure 9] Diagram showing a configuration example 4 of the communication satellite group according to Embodiment 1. [Figure 10] Diagram showing the communication method of the communication satellite group according to Embodiment 1. [Figure 11] Diagram showing a configuration example of the satellite information transmission system according to Embodiment 2. [Figure 12] Diagram showing an overall configuration example of the satellite information transmission system according to Embodiment 2. [Figure 13] Diagram showing the communication method of the communication satellite group according to Embodiment 2. [Figure 14] Diagram showing a diagram for explaining the ground facilities according to Embodiment 3. [Figure 15] Diagram showing a diagram for explaining Example 1 of the communication satellite according to Embodiment 3. [Figure 16] Diagram showing a diagram showing an example of the satellite information transmission system according to Embodiment 3. [Figure 17] Diagram showing a diagram for explaining Example 2 of the communication satellite according to Embodiment 3. [Figure 18] Diagram showing a configuration example of the monitoring system according to Embodiment 4. [Figure 19] Diagram showing a configuration example of Example 1 of the first satellite constellation according to Embodiment 4. [Figure 20] Diagram showing a configuration example of Example 2 of the first satellite constellation according to Embodiment 4. [Figure 21] Diagram showing a configuration example of Example 4 of the second satellite constellation according to Embodiment 4. [Figure 22] [[ID=(45)]]Diagram showing Example 1 of the communication method of the satellite information transmission system according to Embodiment 5. [Figure 23] Diagram showing an overall configuration example of the satellite information transmission system according to Embodiment 5. [Figure 24] Diagram showing Example 6 of the communication method of the satellite information transmission system according to Embodiment 5. [Figure 25] Diagram showing a configuration example of the artificial satellite according to Embodiment 6. [Figure 26] A diagram showing an example configuration of a communications satellite constellation according to Embodiment 6. [Figure 27] A diagram showing an example configuration of a satellite constellation according to Embodiment 6. [Figure 28] A diagram showing another example of the configuration of the satellite constellation according to Embodiment 6. [Figure 29] A diagram showing an example configuration of Example 1 of the satellite information transmission system according to Embodiment 6. [Figure 30] A diagram showing an example configuration of Example 2 of the satellite information transmission system according to Embodiment 6. [Figure 31] A diagram showing an example configuration of Example 3 of the satellite information transmission system according to Embodiment 6. [Figure 32] A diagram showing an example configuration of Example 4 of the satellite information transmission system according to Embodiment 6. [Figure 33] A diagram showing an example configuration of Example 5 of the satellite information transmission system according to Embodiment 6. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of the embodiments, the description of the same or corresponding parts will be omitted or simplified as appropriate. Also, the size relationships of the components in the following drawings may differ from those of the actual components. In addition, in the description of the embodiments, directions or positions such as "top," "bottom," "left," "right," "front," "back," "front," and "back" may be indicated. These notations are used for the convenience of explanation only and do not limit the arrangement and orientation of components such as devices, equipment, or parts.

[0011] Embodiment 1. ***Description of the overall configuration of the Satellite Monitoring System 500*** Figure 1 is a diagram showing an example of the overall configuration of the satellite monitoring system 500 according to this embodiment. The satellite monitoring system 500 includes a constellation of monitoring satellites 52 that monitor the critical infrastructure 51, and a monitoring center 53. The satellite monitoring system 500 may also include the critical infrastructure 51 in addition to the constellation of monitoring satellites 52 and the monitoring center 53. The monitoring satellite 521 is also called a monitoring satellite or monitoring device.

[0012] Critical infrastructure 51 is infrastructure in outer space. A concrete example of critical infrastructure 51 is formed by a constellation of satellites that constitute social infrastructure, such as the following: • Information exchange with distant or remote regions via communication satellites. • Weather forecasts using images from the Himawari weather satellite. • Utilization of geospatial information from quasi-zenith positioning satellites Furthermore, the satellites that make up the critical infrastructure 51 are called infrastructure satellites 511.

[0013] The monitoring satellite constellation 52 consists of monitoring satellites 521 that monitor infrastructure satellites 511, which constitute the critical infrastructure 51. The monitoring center 53 is installed on the ground and exchanges information with the monitoring satellite 521 of the monitoring satellite constellation 52. The monitoring satellite 521 of the monitoring satellite constellation 52 and the monitoring center 53 exchange information via the communication equipment installed on the infrastructure satellite 511.

[0014] The satellite constellation Infrastructure satellite 511 includes all or part of the following: communications satellite 401, data relay satellite 402, weather satellite 403, observation satellite 404, first observation and surveillance satellite 405, positioning satellite 406, second observation and surveillance satellite 407, space station 408, lunar and planetary exploration satellite 409, exploration satellite 410, and transport vehicle 411. Exploration satellite 410 is an exploration satellite that explores planets other than the Moon or resources. The 1st Observation and Monitoring Satellite 405 is a satellite deployed in high orbits, such as geostationary or Molniya orbit, to perform wide-area observations or surveillance of the ground. The 2nd Observation and Monitoring Satellite 407 is an observation or monitoring satellite used to collect various important image information, such as large-scale disasters.

[0015] In addition, infrastructure-specific ground equipment 54 corresponding to the critical infrastructure 51 is installed on the ground. Infrastructure-specific ground equipment 54 is an example of ground equipment installed on the ground that exchanges information with each infrastructure satellite of the infrastructure satellite constellation 510.

[0016] Factors such as debris collisions due to the increasing number of objects in the space environment are increasing the risk of hazardous events that involve the failure or loss of critical infrastructure 51. Therefore, a mechanism is needed to monitor critical infrastructure 51 and take mitigation actions if necessary.

[0017] The monitoring satellite constellation 52 includes an infrastructure satellite 511 equipped with communication equipment for communicating with the monitoring center 53, which is designated as monitoring satellite 521. The monitoring satellite 521 includes all or part of the optical monitoring satellite 421, the radio 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 optics. The radio monitoring satellite 423 monitors the infrastructure satellite 511 using radio waves. The infrared monitoring satellite 422 monitors the infrastructure satellite 511 using infrared detection. The service satellite 424 provides on-orbit services to the infrastructure satellite 511. The debris removal satellite 425 removes debris.

[0018] On-orbit services include, in whole or in part, capture, inspection, repair, refueling, relocation, de-orbiting (ADR: Active Debris Removal), and laser irradiation.

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

[0020] Furthermore, monitoring services that use auditory means to keep an eye on things have the objective of monitoring radio waves in outer space where sound waves do not propagate. To achieve the objective of monitoring critical infrastructure 51 using satellites, an effective method is to receive radio waves flying around the area and monitor the radio wave conditions that could cause malfunctions.

[0021] Furthermore, as an extension of monitoring services, on-orbit services can be cited as an analogy to the role of manual operation. On-orbit services include services such as capturing, inspecting, and repairing malfunctioning satellites. They also include services such as refueling satellites that have run out of fuel, relocation services to move the service location, and active orbital removal (ADR) for satellites that cannot deorbit on their own after the end of their lifespan. Additionally, there are services that use lasers to monitor the distance to suspicious objects such as debris.

[0022] Thus, it is hoped that the monitoring satellite 521 will fulfill the roles of eyes, ears, or hands. However, there are limitations to the role of the mouth, that is, the means of communication for transmitting monitoring information 590, and ingenuity is required.

[0023] In this embodiment, the infrastructure satellite 511 is used as the monitoring satellite 521 that acts as the mouth, that is, the monitoring satellite 521 that transmits monitoring information 590. The monitoring satellite 521 includes the infrastructure satellite 511, which acts as the mouth of the monitoring satellite 521. Similarly, the infrastructure satellite 511 includes the monitoring satellite 521, which also acts as the mouth. In other words, the satellite monitoring system 500 contains satellites that are both monitoring satellites 521 and infrastructure satellites 511. While this description primarily focuses on the infrastructure satellite 511 acting as the mouth, such satellites could also function as eyes, ears, and hands.

[0024] As shown in Figure 1, the monitoring satellite 521 that performs long-distance communication includes the communications satellite 401 and the data relay satellite 402 in the first satellite constellation 601. It also includes the communications satellite 401 in the second satellite constellation 602. Furthermore, it includes the lunar and planetary exploration satellite 409 in the third satellite constellation 603. The monitoring satellite 521, which conducts short-range communications, includes the weather satellite 403, the positioning satellite 406, and the observation satellite 404 in the first satellite constellation 601.

[0025] As shown in Figure 1, the satellite monitoring system 500 comprises a first satellite constellation 601, a second satellite constellation 602, a third satellite constellation 603, and a monitoring center 53. The first satellite constellation, 601, consists of satellites orbiting near geostationary Earth orbit (GEO) or near quasi-zenith orbit (QZO). The second satellite constellation, 602, consists of satellites orbiting in the vicinity of medium-altitude Earth orbit (MEO) or low-altitude Earth orbit (LEO). The third satellite constellation, 603, consists of satellites orbiting in cislunar space, which is the space between the Moon and the Earth, or beyond the Moon.

[0026] Figure 2 shows an example of the configuration of the monitoring center 53 according to this embodiment. The monitoring center 53 is also known as ground equipment 701, which is installed on the ground. Here, it will be described as ground equipment 701.

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

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

[0029] The functions of the monitoring and management unit 710 are implemented 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. Furthermore, the storage unit 720 may be divided and provided in the memory 921 and the auxiliary storage device 922.

[0030] Ground equipment 701 exchanges monitoring information 590 with monitoring satellite 521 via infrastructure satellite 511. The monitoring management unit 710 uses the monitoring information 590 exchanged with monitoring satellite 521 to implement functions to address the risk of failure or loss of critical infrastructure 51. For example, the monitoring management unit 710 implements functions such as warning of hazards, preventing hazards, or avoiding hazards in critical infrastructure 51.

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

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

[0033] Memory 921 is a storage device that temporarily stores data. Specific examples of memory 921 include SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). The auxiliary storage device 922 is a storage device for storing data. A specific example of the auxiliary storage device 922 is an HDD. Alternatively, the auxiliary storage device 922 may be a portable storage medium such as an SD® memory card, CF, NAND flash, flexible disk, optical disk, compact disk, Blu-ray® disc, or DVD. HDD is an abbreviation for Hard Disk Drive. SD® is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash®. DVD is an abbreviation for Digital Versatile Disk.

[0034] The input interface 930 is a port to which input devices such as a mouse, keyboard, or touch panel are connected. Specifically, the input interface 930 is a USB (Universal Serial Bus) terminal. Alternatively, the input interface 930 may be a port connected to a LAN (Local Area Network). The output interface 940 is a port to which the cable of a display device 941, such as a display, is connected. Specifically, the output interface 940 is a USB terminal or an HDMI® (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. Memory 921 stores not only the monitoring management program but also the OS (Operating System). The processor 910 executes the monitoring management program while running the OS. The monitoring management program and OS may also be stored in auxiliary storage. The monitoring management program and OS stored in auxiliary storage are loaded into 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 equipment 701 may have multiple processors that replace the processor 910. These multiple processors share the task of executing the monitoring and management program. Each processor is a device that executes the monitoring and management program, just like the processor 910.

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

[0039] The word "department" in "monitoring management department 710" may be replaced with "processing," "procedure," or "process." Similarly, the word "processing" in "monitoring management processing" may be replaced with "program," "program product," or "computer-readable storage medium containing a program." The monitoring management program causes the computer to execute each process, procedure, or process, replacing "department" in the monitoring management department with "process," "procedure," or "process." The monitoring management method is performed by the ground equipment 701 executing the monitoring management program. The monitoring and management program may be provided on a computer-readable recording medium or storage medium. Alternatively, the monitoring and management program may be provided as a program product.

[0040] Furthermore, the processor may be replaced by an electronic circuit. Both the processor and the electronic circuit are also called processing circuits. In other words, the functions of each device in the satellite monitoring system 500 are realized by processing circuits.

[0041] Figure 3 shows an example configuration of a satellite 30, which is an example of a space object according to this embodiment. Satellite 30 comprises a satellite control device 310, a communication device 32, a propulsion device 33, an attitude control device 34, and a power supply device 35. While it also includes other components for various functions, Figure 3 illustrates the satellite control device 310, communication device 32, propulsion device 33, attitude control device 34, and power supply device 35. Satellite 30 is an example of a space object.

[0042] The satellite control device 310 is a computer that controls the propulsion system 33 and the attitude control device 34, and is equipped with processing circuits. Specifically, the satellite control device 310 controls the propulsion system 33 and the attitude control device 34 according to various commands transmitted from the ground equipment. The satellite communication device 32 is a device that communicates with ground equipment or ground devices. Specifically, the communication device 32 transmits various data related to its own satellite to the ground devices. The communication device 32 also receives various commands transmitted from the ground devices. The propulsion system 33 is a device that provides thrust to the satellite 30 and changes the speed of the satellite 30. Specifically, the propulsion system 33 is an apogee kick motor, a chemical propulsion system, or an electric propulsion system. An apogee kick motor (AKM) is an upper-stage propulsion system used to insert 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). Chemical propulsion systems are thrusters that use mono-liquid or di-liquid fuels. Electric propulsion systems include ion engines or Hall thrusters. An apogee kick motor is a device used for orbital transitions and is sometimes a type of chemical propulsion system. The attitude control device 34 is a device for controlling attitude elements such as the attitude of the satellite 30, its angular velocity, and its line of sight. The attitude control device 34 changes each attitude element in a desired direction, or maintains each attitude element in a desired direction. The attitude control device 34 comprises attitude sensors, actuators, and a controller. The attitude sensors include devices such as gyroscopes, Earth sensors, solar sensors, star trackers, thrusters, and magnetic sensors. The actuators include devices such as attitude control thrusters, momentum wheels, reaction wheels, and control moment gyros. The controller controls the actuators according to the data measured by the attitude sensors or various commands from ground equipment. The power supply unit 35 is equipped with devices such as solar cells, batteries, and a power control device, and supplies power to each device mounted on the satellite 30.

[0043] The processing circuits provided in the satellite control device 310 will now be described. The processing circuit may be dedicated hardware, or it may be a processor that executes a program stored in memory. In a processing circuit, some functions may be implemented by dedicated hardware, while the remaining functions are implemented by software or firmware. In other words, a processing circuit can be implemented using hardware, software, firmware, or a combination thereof. The dedicated hardware specifically includes single circuits, complex circuits, programmed processors, parallel programmed processors, ASICs, FPGAs, or combinations thereof. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array.

[0044] Figure 4 shows an example of the configuration of the communications satellite 401 according to this embodiment. Figure 5 shows an example of the configuration of the observation satellite 404 according to this embodiment. Figure 6 shows another example of the configuration of the observation satellite 404 according to this embodiment. Note that in Figures 3 to 6, components with the same name have similar functions, and their explanations may be omitted.

[0045] Based on Figure 4, the configuration of communications satellite 401 will be explained. The communications satellite 401 is equipped with a communications device 121, a propulsion device 122, a power supply device 123, and a camera 124. For example, camera 124 is a wide-angle camera that points in the same direction as the first directional antenna 121E or the second directional antenna 121W.

[0046] The communications satellite 401 allows for the visual observation of the observation satellite and other space objects orbiting in geostationary or near-geostationary orbit. This enables visual confirmation that the environment around communications satellite 401 is free from obstacles that could cause interference and noise in communications. Other cosmic objects are separate cosmic objects from those observed by observation satellites.

[0047] By positioning camera 124 so that the line of sight vector is from communications satellite 401 to Earth, observation satellite 404 and other space objects flying in geostationary or near-geostationary orbit can be visually captured. Furthermore, it becomes possible to estimate the positions of other space objects in orbit. Therefore, it is possible to visually confirm that the environment around communications satellite 401 is free from communication interference and noise.

[0048] Based on Figure 5, the configuration of observation satellite 404 will be explained. Observation satellite 404 is equipped with an observation instrument 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. Observation device 111 is a device for observing objects in space. Observation device 111 is also called a monitoring device. Camera 117 is, for example, a wide-angle camera pointed towards the communications satellite 401.

[0049] Camera 117 allows for the visual capture of communication satellite 401 and other space objects orbiting in geostationary or near-geostationary orbit. This allows for visual confirmation that the environment around observation satellite 404 is free from interference and noise for communications.

[0050] By positioning the camera 117 so that the line of sight vector is from the observation satellite 404 to the communications satellite 401, it is possible to visually capture the communications satellite 401 and other space objects flying in geostationary or near-geostationary orbit. Furthermore, it becomes possible to estimate the positions of other space objects in 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 Figure 6, another example of the configuration of observation satellite 404 will be explained. Observation satellite 404 is equipped with an observation instrument 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] Observation device 201 is a device for observing objects in space. Observation device 201 is a device that detects space objects using an optical system. Observation device 201 uses an optical system to photograph space objects flying at altitudes different from the observation satellite's orbital altitude. Specifically, observation device 201 is a visible optical sensor. The observation device 201 generates observational data. This observational data is obtained through observations performed by the observation device 201. For example, the observational data corresponds to data representing an image of a space object.

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

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

[0055] ***Description of the configuration and operation of the Satellite Monitoring System 500*** In this embodiment, the configuration and operation of the satellite monitoring system 500 in the second satellite constellation 602 shown in Figure 1 will be described.

[0056] <Example of overall configuration of the Satellite Monitoring System 500> In this embodiment, the critical infrastructure 51 is social infrastructure in outer space. The critical infrastructure 51 is composed of a constellation of infrastructure satellites 510, which consists of infrastructure satellites 511 flying in an Earth orbit (LEO: Low Earth Orbit) at an orbital altitude of 500 km to 2000 km. The monitoring satellite constellation 52 consists of monitoring satellites 521 that orbit at an altitude of 2000 km or less, monitoring the infrastructure satellite constellation 510 and providing on-orbit services. Infrastructure-specific ground equipment 54 is an example of ground equipment installed on the ground that exchanges information with each infrastructure satellite 511 of the infrastructure satellite constellation 510. Monitoring Center 53 is an example of ground equipment installed on the ground that exchanges information with monitoring satellite 521.

[0057] As shown in Figure 1, the infrastructure satellite constellation 510 includes a communications satellite constellation 44 consisting of communications satellites 401.

[0058] The 44 communications satellites fly in approximately equal arrangements, each in an orbit with an orbital altitude and inclination that results in a sun-synchronous orbit that completes an integer number of orbits per day. Communications satellite 401 communicates with communications satellites flying in front of and behind it. The communications satellite constellation 44 includes a first satellite 61 that communicates with ground facilities such as infrastructure ground equipment 54, a second satellite 62 that communicates with the monitoring satellite 521b, and a third satellite 63 that only communicates with communications satellites flying in front of and behind it. The monitoring satellite 521b and the monitoring center 53 exchange information via the communication satellite constellation 44.

[0059] Figure 7 shows an example configuration of the satellite monitoring system 500 according to this embodiment. In Figure 7, the monitoring satellite 521b, which acts as the ears, communicates with the communication satellite 401, which is both the infrastructure satellite 511 and the monitoring satellite that acts as the mouth. The communication satellite 401 communicating with the monitoring satellite 521b is an example of the second satellite 62. Here, the monitoring satellite 521b, which acts as the ears, may also be the monitoring satellite 521a, which acts as the eyes, or the monitoring satellite 521c, which acts as the hands. The monitoring satellite 521b, which acts as the ears, and the communications satellite 401, which is an example of a second satellite 62, are equipped with a second communications device 42 that communicates with other infrastructure satellites.

[0060] The communications satellite 401, an example of the first satellite 61, is equipped with a first communications device 41 for communicating with ground facilities. The communications satellite 401, an example of the first satellite 61, is also equipped with a second communications device 42 for communicating with other infrastructure satellites.

[0061] A communications satellite 401, which is an example of a third satellite 63 that only communicates with communications satellites flying in front of or behind it, is equipped with a second communications device 42 that communicates with other infrastructure satellites.

[0062] In the satellite constellation that orbits LEO, if infrastructure satellite 511 is orbiting on the other side of the Earth, it may not be possible to maintain communication with monitoring center 53 even if an emergency situation requiring response occurs. However, according to the satellite monitoring system 500 of this embodiment, multiple communication satellites are provided with an environment in which they communicate with each other, allowing monitoring information to be sent and received from the other side of the Earth via multiple communication satellites. Therefore, it has the effect of allowing monitoring information to be sent and received with the monitoring center anytime, anywhere. Therefore, this has the effect of enabling immediate evasive action if dangerous space objects such as space debris approach the infrastructure satellite 511.

[0063] <Example 1 of the configuration of the 44th communications satellite constellation> Each communications satellite 401 in the communications satellite constellation 44 orbits in a sun-synchronous orbit at an altitude of approximately 1666 km, completing 12 orbits per day. The communications satellite constellation 44 consists of five or more communications satellites 401.

[0064] With an orbital altitude of approximately 1666 km, completing 12 orbits per day, and setting the orbital inclination to 77° (180°-103°), it becomes a sun-synchronous orbit. If five satellites fly in this orbit with equal phases, the radius of the inscribed circle of the pentagon they form will be larger than the Earth's radius, thus ensuring a clear communication field between the satellites. Assuming that atmospheric effects can be ignored at an altitude of 300 km, six or more satellites would allow for the establishment of communication lines at an altitude of 585 km or higher above the Earth's surface. Furthermore, because it revisits the same latitude at the same time every day, every two hours, it has the effect of enabling information exchange with ground equipment at a fixed time every two hours.

[0065] <Example 2 of the configuration of the 44th communications satellite constellation> Each of the 44 communications satellites, 401, flies in a sun-synchronous orbit at an altitude of approximately 1248 km, completing 13 orbits per day. The 44 communications satellite group consists of six or more communications satellites.

[0066] With an orbital altitude of approximately 1248 km, completing 13 orbits per day, setting the orbital inclination to 79° (180°-101°) results in a sun-synchronous orbit. If the six satellites fly in this orbit with equal phases, the radius of the inscribed circle of the hexagon they form will be larger than the Earth's radius, thus ensuring a clear communication field between the satellites. Assuming an altitude of 300 km where atmospheric effects can be ignored, seven or more satellites would allow for communication lines to be established at an altitude of 491 km or higher above the Earth's surface. Since it revisits the same latitude at the same time every day, every 111 minutes, it has the effect of enabling ground equipment to exchange information at a fixed time every day, every 111 minutes.

[0067] <Example 3 of the configuration of the 44th communications satellite constellation> Each of the 44 communications satellites, 401, flies in a sun-synchronous orbit at an altitude of approximately 881 km, completing 14 orbits per day. The 44 communications satellite group consists of seven or more communications satellites.

[0068] Figure 8 shows an example of configuration 3 of the communication satellite constellation 44 according to this embodiment. With an orbital altitude of approximately 881 km, completing 14 orbits per day, and setting the orbital inclination to 81° (180°-99°), it becomes a sun-synchronous orbit. By setting orbital parameters to synchronize with the sun at an orbital altitude of 881 km, an orbit that completes 14 orbits per day can be achieved. If seven satellites fly in this orbit with equal phases, the radius of the inscribed circle of the hexagon they form will be larger than the Earth's radius, thus ensuring a clear communication field between the satellites. Assuming that atmospheric effects can be ignored at an altitude of 300 km, eight or more satellites would allow for the establishment of communication lines at an altitude of 327 km or higher above the Earth's surface.

[0069] Since it revisits the same latitude at the same time every day, every 103 minutes, it has the effect of enabling information exchange between ground equipment at a fixed time every day, every 103 minutes. Note that an orbital inclination of 77° is equivalent to 103° depending on the definition. Also, an orbital inclination of 79° is equivalent to 101° depending on the definition. Furthermore, an orbital inclination of 81° is equivalent to 99° depending on the definition.

[0070] <Example of configuration of communications satellite constellation 44, part 4> Communications satellite constellation 44 is in a sun-synchronous orbit and consists of satellites in two orbital planes: LST 9:00 and LST 15:00. LST stands for Local Sun Time.

[0071] Figure 9 shows an example configuration 4 of the communication satellite constellation 44 according to this embodiment. Sun-synchronous orbits are frequently used for Earth observation satellites. Optical satellites often use orbits near LST10:30 and LST13:30, which have favorable sunlight conditions. Radar satellites also frequently use orbits at LST06:00 and LST18:00, which are advantageous for solar power generation. If the orbital altitude of the communications satellite is 881 km, the inscribed circle of the regular octagon will be 6727 km, thus ensuring a communication link with any LST's monitoring satellite. The monitoring satellite can also be a user satellite that utilizes the communications satellite constellation 44 as its communication link. Therefore, if communication satellites are deployed in two orbital planes, LST09:00 and LST15:00, it becomes possible to communicate with all of the satellite constellations frequently used for Earth observation.

[0072] <Communication methods for the 44th satellite constellation> Figure 10 is a diagram showing the communication method of the communication satellite constellation 44 according to this embodiment. The communication satellite 401 and the monitoring satellite 521 are equipped with a two-way communication terminal 65 that has a transmit / receive switching device 64 that enables reception and transmission by switching between receiving and transmitting functions. The ground equipment 701, which is the monitoring center 53, operates the transmit / receive switching device 64 so that the ratio of the receiving time to the transmitting time of the monitoring satellite 521 is α to β, based on the amount of data α of the command to be transmitted to the monitoring satellite 521 and the amount of monitoring data and telemetry data β received from the monitoring satellite 521. Specifically, the ground equipment 701 operates the transmit / receive switching device 64 so that the ratio of the receiving operation time when the receiving function of the two-way communication terminal 65 is operating and the transmitting operation time when the transmitting function is operating is α to β, based on the amount of data α of the command to be transmitted to the monitoring satellite 521 and the amount of data β of the monitoring report data received from the monitoring satellite 521. The monitoring satellite 521 and the ground equipment 701 exchange information via the communication satellite 401.

[0073] In this embodiment, an example configuration for exchanging commands and monitoring report data between a monitoring satellite and a monitoring center has been described. However, the monitoring satellite may be any other user satellite that uses the communication satellite constellation 44 as a communication line.

[0074] Embodiment 2. This embodiment mainly describes the points that are added to or differ from Embodiment 1. Note that components similar to those in Embodiment 1 are denoted by the same reference numerals, and their descriptions may be omitted.

[0075] Embodiment 1 primarily describes a 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. In this embodiment, a satellite information transmission system 501 is described in which a user satellite 531 and ground equipment 702 exchange information via a communication satellite constellation 44 included in the infrastructure satellite constellation 510.

[0076] Figure 11 shows an example of the configuration of the satellite information transmission system 501 according to this embodiment. Figure 12 shows an example of the overall configuration 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 the same as that of the satellite monitoring system 500 described in Embodiment 1, except that the monitoring satellite 521 is replaced with the user satellite 531 and the monitoring center 53 is replaced with the ground equipment 702.

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

[0078] The satellite information transmission system 501 comprises a critical infrastructure 51 consisting of a constellation of infrastructure satellites 510 orbiting the Low Earth Orbit (LEO), and ground equipment 702 that exchanges information with each of the infrastructure satellites in the constellation 510. The infrastructure satellite constellation 510 consists of a communications satellite constellation 44 and a user satellite constellation 530, which consists of user satellites 531 that utilize the communications satellite constellation 44 as a communication link.

[0079] As shown in Figures 11 and 12, the communications satellite constellation 44 flies in orbits with orbital altitudes and orbital inclinations that result in sun-synchronous orbits with integer rotations per day, arranged in a substantially equal configuration. Communications satellite 401 communicates with communications satellites flying in front of and behind it. The communications satellite constellation 44 comprises a first satellite 61 that communicates with the ground facilities 702, a second satellite 62 that communicates with the user satellite 531, and a third satellite 63 that only communicates with communications satellites flying in front of or behind it. The user satellite 531 and the ground facilities 702 exchange information via the communications satellite constellation 44.

[0080] <Examples 1 to 4 of the 44 communications satellite constellation configurations> Furthermore, the same configurations as those described in Configuration Examples 1 to 4 of the communication satellite group 44 described in the embodiment can also be applied to the configuration examples of the communication satellite group 44 according to this embodiment.

[0081] <Communication methods for the 44th satellite constellation> The communication method for the communication satellite constellation 44 according to this embodiment can also be the same as the communication method for the communication satellite constellation 44 described in the embodiment.

[0082] Figure 13 is a diagram showing the communication method of the communication satellite constellation 44 according to this embodiment. The communication satellite 401 and the user satellite 531 are equipped with a bidirectional communication terminal 65 that includes a transmit / receive switching device 64. The ground equipment 702 operates the transmit / receive switching device 64 so that the ratio of the user satellite 531's reception time to transmission time is α to β, based on the amount of data α of the command to be transmitted to the user satellite 531 and the amount of data β of the user information data to be received from the user satellite 531. User satellite 531 and ground equipment 702 exchange information via the communication devices of the communication satellite constellation 44.

[0083] Embodiment 3. This embodiment mainly describes the points that are added to or differ from Embodiments 1 and 2. Note that components similar to those in Embodiments 1 and 2 are denoted by the same reference numerals, and their descriptions may be omitted.

[0084] <Ground Equipment> This embodiment describes the ground equipment used in the satellite monitoring system 500 or the satellite information transmission system 501 described in Embodiments 1 and 2. Examples of ground equipment include the ground equipment 701 of the monitoring center 53, the ground equipment 54 for each infrastructure, or the ground equipment 702 that exchanges information with the user satellite 531.

[0085] Figure 14 is a diagram illustrating the ground equipment according to this embodiment. The ground equipment used in the satellite monitoring system 500 or satellite information transmission system 501 described in Embodiments 1 and 2 is installed at a latitude of 60° or higher and communicates with the first satellite 61, "the first," in each orbit.

[0086] The Earth's rotation period and its orbital period are different. Therefore, when a communications satellite orbiting in an LST09:00 orbit communicates with ground equipment, for example, ground equipment located near the equator may only be able to communicate twice, around AM09:00 and PM09:00. In contrast, ground equipment located at high latitudes can communicate with the satellite every time it orbits the Earth, even though the Earth's rotation period and its orbital period are different.

[0087] <Example 1 of a communications satellite> Next, we will describe Example 1 of a communication satellite 401 used in the satellite monitoring system 500 or satellite information transmission system 501 described in Embodiments 1 and 2.

[0088] Figure 15 illustrates Example 1 of a communications satellite according to this embodiment. In Example 1 of a communications satellite, communications satellite 401 is equipped with a first communications device 41 for communicating with ground facilities and three second communications devices 42 for communicating with other infrastructure satellites. In Example 1 of a communications satellite, communications satellite 401 communicates simultaneously with communications satellites orbiting in the same orbital plane, as well as with monitoring satellites or user satellites.

[0089] If a system is equipped with one set of first communication devices for communicating with ground facilities and three sets of second communication devices for communicating between infrastructure satellites, it can communicate simultaneously with communication satellites orbiting in the same orbital plane, as well as with monitoring satellites or user satellites. Furthermore, the communication satellite according to Example 1 of this embodiment has the effect of being able to transmit information communicated with the user satellite to ground facilities in real time. Therefore, even in situations where the number of satellites orbiting in the same orbital plane is small during the construction of critical infrastructure, this has the effect of enabling information exchange between user satellites and ground equipment. Furthermore, since communication terminals can be standardized, there is the added benefit of reducing total costs.

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

[0091] Figure 16 shows an example of a satellite information transmission system 501 according to this embodiment. In the second example of a communications satellite, the communications satellite 401 includes a first communications device 41 for communicating with ground facilities, a second communications device 42 for communicating with other infrastructure satellites, and a third communications device 43 for communicating with the monitoring satellite 521 or the user satellite 531.

[0092] Figure 17 illustrates Example 2 of a communications satellite according to this embodiment. In Example 2 of a communications satellite, communications satellite 401 is equipped with one set of first communications equipment for communicating with ground facilities, two sets of second communications equipment for communicating with infrastructure satellites flying in front of and behind the orbital plane, and one set of third communications equipment for communicating with a monitoring satellite or user satellite. This has the effect of transmitting information communicated with the user satellite to ground facilities in real time. Therefore, even in situations where the number of satellites orbiting in the same orbital plane is small during the construction of critical infrastructure, this has the effect of enabling information exchange between user satellites and ground equipment. Furthermore, by dedicating terminals to monitoring satellites or user satellites, communication becomes possible even with small terminals with small aperture diameters, thus enabling the implementation of monitoring satellites or user satellites using small satellites.

[0093] Embodiment 4. This embodiment mainly describes the points that are added to or different from Embodiments 1 to 3. Note that components similar to those in Embodiments 1 to 3 are denoted by the same reference numerals, and their descriptions may be omitted.

[0094] This embodiment describes a monitoring system 502 in which satellites comprising a first satellite constellation 810, which monitors the Earth, flying objects, and space objects, exchange satellite information with ground facilities via satellites comprising a second satellite constellation 820.

[0095] <Example of overall configuration of monitoring system 502> Figure 18 shows an example of the configuration of the monitoring system 502 according to this embodiment. In the monitoring system 502, satellite 811, which is part of the first satellite constellation 810 that monitors the Earth, flying objects, and space objects, exchanges information with ground facilities and satellite information via satellite 812, which is part of the second satellite constellation 820.

[0096] The first satellite constellation, 810, consists of a group of three or more satellites working together to monitor the Earth, flying objects, and space objects. The ground facilities will exchange information with the constituent satellites that make up the first satellite constellation 810. The second satellite constellation, 820, will orbit in a sun-synchronous orbit at an altitude of 800 km or higher in a nearly evenly spaced configuration. It will relay satellite information in cooperation with a group of six or more communication satellites that will communicate with satellites orbiting in front of or behind it on the same orbital plane. In other words, the satellites that make up the second satellite constellation, 820, are a group of six or more communication satellites.

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

[0098] In recent years, the emergence of supersonic gliding vehicles has raised expectations for satellite-based launch and flight path tracking. However, establishing a constant communication environment can be difficult with LEO constellations.

[0099] Another technology involves exchanging information via data relay satellites in geostationary orbit. However, as the number of orbiting satellites increases and the frequency of use of data relay satellites increases, communication lines may become unavailable in emergencies. Also, because information is transmitted from LEO satellites to ground facilities via geostationary orbit, time delays may occur.

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

[0101] Furthermore, increasing the number of satellites in the second satellite constellation increases the number of satellites in the first satellite constellation that can simultaneously exchange data. This has the effect of enabling the simultaneous exchange of monitoring data for a large number of monitored targets. Furthermore, increasing the number of satellites in the second satellite constellation increases the number of ground facilities that can simultaneously exchange data. This has the effect of enabling simultaneous response actions for a large number of monitored targets.

[0102] Furthermore, even when using sun-synchronous orbit satellites to monitor the Earth, flying objects, or space objects with visible high-resolution optical monitoring equipment, there is a challenge in that the time during which information can be exchanged at ground facilities installed at specific longitudes is limited. Similar challenges existed even when using geostationary data relay satellites. The monitoring system 502 according to this embodiment has the effect of being usable for emergency responses such as disasters by realizing a constant communication environment via a constellation of low Earth orbit communication satellites.

[0103] While geostationary orbits are commonly used for satellites orbiting the equator, geostationary satellites orbiting at an altitude of 36,000 km face the challenge of difficult high-resolution monitoring. Therefore, adopting an orbit that orbits the equator multiple times a day would enable high-resolution monitoring. However, even in this case, there is the challenge that constant communication cannot be maintained with only ground equipment installed at specific longitudes. Thus, this approach would enable the realization of a constellation of satellites orbiting the equator that can maintain constant communication.

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

[0105] Figure 19 shows an example configuration of Example 1 of the first satellite constellation 810 according to this embodiment. Let "N" be the number of times each constituent satellite orbits the Earth in a day. The first satellite constellation, 810, consists of N satellites. Each component satellite travels in an inclined circular orbit, completing N orbits around the Earth per day. The plane formed by the orbits of each component satellite is called the orbital plane. The N orbital planes formed by the N satellites are such that their normals are shifted by 360 degrees N in the azimuth direction. In other words, the relative angles of the azimuth component are shifted by 360 degrees N. The azimuth direction corresponds to the direction of travel of the satellites. That is, the azimuth direction corresponds to the longitude direction, or east-west direction.

[0106] Specifically, the first satellite constellation 810 consists of eight constituent satellites (A to H) and forms eight orbital planes. Each of the constituent satellites orbits the Earth eight times a day. The normals of each of the eight orbital planes are offset from one another by 45 degrees in their azimuth components.

[0107] The timing of the N satellites (A-H) passing the northernmost point of their respective orbital planes is synchronized. In other words, the N satellites (A-H) pass the northernmost point 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, unfrozen elliptical orbit with a perigee altitude of 300 km or more and an apogee altitude of 6000 km or less. The multiple orbital planes formed by the multiple constituent satellites included in the first satellite constellation 810 are offset by equal angles in the azimuth component of each other's major axes.

[0109] Figure 20 shows an example configuration of Example 2 of the first satellite constellation 810 according to this embodiment. Figure 20 shows Example 2 of the first satellite constellation 810 as viewed from the direction normal to the orbital plane. The first satellite constellation, 810, comprises multiple component satellites (A-C). Each component satellite orbits in a sun-synchronous elliptical orbit. Each elliptical orbit has high eccentricity and orbital inclination. In other words, the orbit of each component satellite is a sun-synchronous orbit, an inclined orbit, and an elliptical orbit. Furthermore, each component satellite's elliptical orbit is an unfrozen orbit. That is, each component satellite's elliptical orbit is not a frozen orbit, and over time, the major axis of each elliptical orbit rotates around the Earth within the orbital plane.

[0110] The three satellites (A-C) alternately monitor the target area of ​​Earth from their perigee, apogee, or midpoint. The midpoint is a point located between the perigee and apogee. At perigee, monitoring can be performed with high resolution, albeit for a short period of time. At afar, long-term monitoring is possible, albeit with low resolution.

[0111] The major axes of the three elliptical orbits are inclined at approximately 120° intervals with respect to the circumferential direction of the orbital plane. The azimuth direction corresponds to the longitude direction, i.e., the east-west direction. The major axis of each elliptical orbit rotates relative to the Sun (10°), but the relative relationship between the three elliptical orbits is maintained.

[0112] <Example 3 of the first satellite constellation 810> Example 3 of the first satellite constellation 810 orbits the equator multiple times a day, with its flight position synchronously controlled by shifting its azimuth component by equal angles. In Example 1 of the first satellite constellation 810 in Figure 19, each constituent satellite is assumed to travel in an inclined circular orbit, completing N orbits of the Earth per day. On the other hand, in Example 3 of the first satellite constellation 810, each constituent satellite travels in an orbit above the equator and orbits the Earth N times per day. Each component satellite travels in an inclined circular orbit, completing N orbits of the Earth per day. The orbital planes in which each component satellite travels are shifted by equal angles in the azimuth direction, ensuring synchronous control of their flight positions.

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

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

[0115] Sun-synchronous orbits are frequently used for Earth observation satellites. Optical satellites often use orbits near LST10:30 and LST13:30, which have favorable sunlight conditions. Radar satellites also frequently use orbits at LST06:00 and LST18:00, which are advantageous for solar power generation. If the orbital altitude of the communications satellite is 881 km, the inscribed circle of the regular octagon will be 6727 km, thus ensuring a communication link with any LST's monitoring satellite. The monitoring satellite can also be a user satellite that utilizes the communications satellite constellation 44 as its communication link. Therefore, as shown in Figure 18, if the satellites comprising the second satellite constellation 820 are deployed in the two orbital planes LST09:00 and LST15:00, it will be possible to communicate with all of the satellite constellations that are frequently used for Earth observation.

[0116] ***Other configurations*** The ground equipment of the monitoring system 502 according to this embodiment may be a mobile unit. For example, if a supersonic gliding projectile is detected, transmitting the information to a mobile unit such as an aircraft, UAV (unmanned aerial vehicle), ship, or vehicle that will directly respond is rational for carrying out a quick response.

[0117] Embodiment 5. This embodiment mainly describes the points that are added to or differ from Embodiments 1 to 4. Note that components similar to those in Embodiments 1 to 4 are denoted by the same reference numerals, and their descriptions may be omitted. This embodiment will primarily describe the communication method of the satellite information transmission system 501.

[0118] <Example 1 of communication methods for satellite information transmission system 501> Figure 22 shows an example of the configuration of the satellite information transmission system 501 according to this embodiment. Figure 23 is a diagram showing an example of the overall configuration of the satellite information transmission system 501 according to this embodiment. The satellite information transmission system 501 according to this embodiment relays satellite information between the user satellite 531, which constitutes a constellation of user satellites orbiting the Earth, and the ground equipment 702. The satellite information transmission system 501 includes a constellation 44 of communication satellites consisting of six or more communication satellites that orbit in a sun-synchronous orbit in an Earth orbit (LEO) at an altitude of 500 km to 2000 km, arranged in a roughly equal configuration, and communicate with communication satellites flying in front of or behind the same orbital plane. Communications satellite 401 communicates with communications satellites flying in front of and behind it.

[0119] In example 1 of the communication method for the satellite information transmission system 501, the communication satellite group 44 comprises a first satellite 61 that communicates optically with the ground equipment 702, a second satellite 62 that communicates optically with the user satellite 531, and a third satellite 63 that only communicates with communication satellites flying in front of and behind it. The communication satellite group 44 communicates with the communication satellites flying in front of and behind it using radio waves. Optical communication is performed by optical communication terminal 544. Radio communication is performed by radio communication terminal 542.

[0120] Optical communication has the advantage of enabling high-capacity data transmission. However, because it requires high-precision alignment of the optical axes between satellites, both the user satellite and the communication satellite need high-precision two-axis directional control. Because the relative position of ground equipment and communication satellites fluctuates significantly, it is necessary to control the constantly changing direction of the satellite in real time with high precision. Similarly, when the relative positions of the user satellite and the communication satellite fluctuate significantly, it is necessary to control the constantly changing directional direction in real time with high precision. When relative position changes are large, the communication time is limited, so high-capacity communication is necessary.

[0121] For a single satellite to simultaneously achieve optical communication between forward and backward communication satellites, the user satellite, and ground facilities, it would be necessary to simultaneously perform high-precision optical axis alignment with different targets. This presents challenges, as it is technically difficult and carries a high risk of communication interruptions. In radio communications, achieving long-distance, high-speed, and high-capacity data transmission requires high-precision alignment of the central axis of the main beam of the radio waves, similar to optical communications. However, for short-range communications, low-speed communications, or communications with limited data volumes, communication is possible without high-precision axis alignment using fixed antennas or omnidirectional antennas.

[0122] In the communication between the satellites in the above-described embodiment, the distance between satellites is limited, and the relative angular variation between the satellites is small. Therefore, it can be achieved not only with optical communication or high-speed, high-capacity radio communication, which require high-precision directional control, but also with radio communication using a fixed antenna. Furthermore, because it allows for constant communication, even with low-speed communication, it has the effect of enabling large-capacity data transfer over time. If communication between the preceding and succeeding satellites is achieved using radio waves that do not require high-precision directional control, then whether the first satellite communicates with ground equipment or the third satellite communicates with the user satellite, the number of communication targets requiring high-precision directional control at any one time will be limited to one. Therefore, directional control will be easier, and the risk of communication interruption will be sufficiently reduced.

[0123] <Example 2 of communication methods for satellite information transmission system 501> In example 2 of the communication method for the satellite information transmission system 501, the radio waves between communication satellites flying in front of and behind are spread spectrally. When satellites flying in the same orbit communicate via radio waves, there is a risk of radio interference or erroneous transmission from multiple satellites flying ahead or behind. By spreading the spectrum and reconstructing only the desired satellite signal, it is possible to avoid radio interference or erroneous transmission.

[0124] <Example 3 of communication methods for satellite information transmission system 501> In example 3 of the communication method for the satellite information transmission system 501, the communication satellite is equipped with a bidirectional communication terminal 65 with a transmit / receive switching function that communicates with communication satellites flying in front of and behind it. A satellite information transmission system is established when a communication satellite is equipped with a transmitting terminal for forward satellites and a receiving terminal for backward satellites, and all satellites in the same orbit communicate with the satellites in front of and behind them. However, there is a challenge in that there is a high risk of communication interruption during the maintenance phase when the satellite is placed into orbit, or if a malfunction occurs in orbit. If a bidirectional communication terminal 65 with a transmit / receive switching function is equipped, satellite information transmission becomes possible even if not all satellites are in orbit.

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

[0126] <Example 5 of communication methods for satellite information transmission system 501> In example 5 of the communication method for the satellite information transmission system 501, the communication satellite constellation 44 includes a fourth satellite that communicates optically with ground facilities and also communicates optically with user satellites. For urgent satellite information, if a single satellite simultaneously handles information exchange between the user satellite and ground facilities, it has the effect of minimizing delay time. The need to simultaneously control two targets with high precision makes the system technically challenging and costly. However, if communication with the forward and backward satellites is also via optical communication, it is significantly easier to implement and less expensive compared to controlling four different targets with high precision. Furthermore, in non-urgent situations, the flight positions from which the user satellite and ground equipment can communicate simultaneously are limited. Therefore, if a single satellite is equipped with communication capabilities for both and communicates in a time-division manner, the number of targets requiring high-precision targeting control at any one time can be limited to one.

[0127] <Example 6 of communication methods for satellite information transmission system 501> Figure 24 shows an example of a communication method 6 for the satellite information transmission system 501 according to this embodiment. The fourth satellite 644 shares the same optical communication terminal 544 for optical communication with the ground equipment 702 and optical communication with the user satellite 531. The fourth satellite 644 rotates around the satellite's direction of travel axis and performs optical communication with the ground equipment 702 and optical communication with the user satellite 531 in a time-division multiplexer manner.

[0128] In non-urgent situations, the flight positions from which the user satellite and ground equipment can communicate simultaneously are limited. Therefore, if a single satellite is equipped with communication capabilities for both and communicates in a time-division manner, the number of targets requiring high-precision targeting control at any one time can be limited to one. Furthermore, standardizing communication terminals between user satellites and ground facilities would result in cost reductions. This is effective when a sufficient number of communication satellites are in orbit and do not deviate from the radio field of view even when rotating around the axis of travel.

[0129] ***Other configurations*** The ground equipment 702 in this embodiment may be a mobile unit. When urgent satellite information needs to be transmitted from fixed ground equipment to a mobile device, directly transmitting the satellite information from the communication satellite to the mobile device minimizes latency. This is particularly effective in situations where even a delay of a few seconds, such as detecting a projectile launch before issuing countermeasures, can increase risk.

[0130] Furthermore, the communications satellite constellation 44 may comprise a first satellite 61 that communicates with ground equipment 702 via radio waves, a second satellite 62 that communicates with user satellite 531 via optical waves, and a third satellite 63 that only communicates with communications satellites flying in front of or behind it. The communications satellite constellation 44 then communicates with communications satellites flying in front of or behind it via radio waves. Optical communication between communications satellites and ground equipment has the problem that communication is not possible when there are clouds. Therefore, if the ground equipment 701 that uses the satellite information transmission system of communication method example 1 is in an area with a high cloud cover rate, using radio waves has the effect of improving availability.

[0131] Embodiment 6. This embodiment mainly describes the points that are added to or different from Embodiments 1 to 5. Note that components similar to those in Embodiments 1 to 5 are denoted by the same reference numerals, and their descriptions may be omitted. This embodiment primarily describes the configuration of a communications satellite constellation, a satellite constellation, and a satellite information transmission system using satellites flying in sun-synchronous orbits as described in Embodiments 1 to 5.

[0132] <Configuration of Satellite 80> Figure 25 shows an example of the configuration of the artificial satellite 80 according to this embodiment. The artificial satellite 80 according to this embodiment is equipped with an AI (Artificial Intelligence) computer or supercomputer and at least one of a cloud server or edge server as an information processing device 81. The satellite 80 flies in a sun-synchronous orbit with LST 06:00 or LST 18:00. At this time, the satellite 80 has solar cells facing the side where sunlight enters and a heat dissipation surface for the information processing device 81 on the opposite side of the sunlight entrance. The satellite 80 has solar cells facing the side where sunlight enters and a heat dissipation surface for, for example, a computer or edge server on the opposite side of the sunlight entrance.

[0133] A sun-synchronous orbit is a type of polar orbit that passes over the polar regions. In a sun-synchronous orbit, the rotation period of the orbital plane around the north-south axis is synchronized with the Earth's orbital period. Therefore, in a sun-synchronous orbit, the angle of incidence of the sun on the orbital plane remains constant throughout the year. Furthermore, in orbits at LST06:00 or LST18:00, the normal vector of the orbital plane points towards the sun, so even low-Earth orbit satellites are constantly illuminated by sunlight without being obscured by the Earth's shadow. Strictly speaking, the normal vector is tilted away from the sun due to the tilt of the Earth's axis, but this effect is minor.

[0134] The computers and servers that act as the "brains" of monitoring satellites are becoming increasingly power-hungry due to the emergence of AI and the increase in server capacity and speed, making heat dissipation a challenge as they are high-heat generating devices. The sun-synchronous orbits LST06:00 or LST18:00 are also called Dondusk orbits. These Dondusk orbits allow low-Earth orbit satellites to avoid the Earth's shadow and continuously generate power using solar panels. Furthermore, because the opposite side of the Dondusk orbit always points towards deep space, it offers excellent heat dissipation through radiative cooling. Therefore, Dondusk orbits offer the advantage of both securing high power and dissipating heat from high-heat generating equipment. The information processing device 81 is an example of a high-heat generating device.

[0135] Furthermore, with the recent increase in scale and speed of cloud computing, the cloud environment on ground systems is also facing challenges such as increased power consumption and heat dissipation measures for high-heat generating equipment. Therefore, by considering satellite 80, which is equipped with edge servers, as part of the IoT, and using distributed computing, it is possible to reduce the load on ground systems and contribute to the SDGs. Furthermore, equipping satellite 80 with a supercomputer or cloud server and establishing a centralized computing system in space would reduce the load on ground systems and contribute to achieving the SDGs. IoT is an abbreviation for Internet of Things. SDGs is an abbreviation for Sustainable Development Goals.

[0136] <Example configuration of the communications satellite constellation 801> Figure 26 shows an example configuration of the communications satellite constellation 801 according to this embodiment. Communications satellite constellation 801 is a satellite constellation that flies in a sun-synchronous orbit with LST 06:00 or LST 18:00. The communications satellite constellation 801 includes communications satellites equipped with communication devices for communicating with the ground. A communications satellite is an example of an artificial satellite 80. Furthermore, the communications satellite constellation 801 is equipped with communication devices that enable communications satellites flying in front of and behind each other in the same orbital plane to communicate with each other, thereby forming a circular communications network.

[0137] According to communications satellite constellation 801, communications satellites can generate electricity continuously using fixed solar panels, which has the effect of enabling the realization of communications satellites at a low cost.

[0138] <Example configuration of satellite constellation 802> Figure 27 shows an example configuration of the satellite constellation 802 according to this embodiment. In Figure 27, the satellite constellation 802 is equipped with edge servers. The satellite constellation 802 will fly in a sun-synchronous orbit with a lasting time of 06:00 or 18:00. Satellite constellation 802 comprises satellites. A satellite is an example of artificial satellite 80.

[0139] The satellite is equipped with a computer or supercomputer that has satellite AI, and at least one of a cloud server or edge server as an information processing device 81. Furthermore, the satellite has solar cells facing the side where sunlight enters, and a heat dissipation surface for the information processing device 81 on the opposite side of the sunlight. The satellite is equipped with solar cells facing the side where sunlight enters, and a heat dissipation surface for, for example, a computer or edge server on the opposite side of the sunlight. The satellite is equipped with communication devices to communicate with the ground.

[0140] Satellite constellation 802 is equipped with communication devices that enable communication between satellites flying in the same orbital plane, forming a circular communication network. In other words, the satellites constellation 802 are equipped with communication devices that enable communication between satellites flying in the same orbital plane, forming a circular communication network.

[0141] Sun-synchronous orbits pass through the polar regions with each orbit. Therefore, according to satellite constellation 802, all satellites can communicate constantly with ground data centers located in high latitudes via a circular communication network.

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

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

[0144] Example 1 of the satellite information transmission system 503 consists of a user satellite constellation, a communication satellite constellation, and ground facilities. The user satellite constellation consists of user satellites orbiting the Earth at an altitude of 500 km to 2000 km (LEO). The communications satellite constellation consists of multiple communications satellites orbiting in a sun-synchronous orbit at LST06:00 or LST18:00. Each satellite in the communications satellite constellation is an example of artificial satellite 80.

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

[0146] In sun-synchronous orbits, due to the Earth's rotation, communication with ground facilities is only possible during the same time period for the LST (Landing Station) satellite in the low to mid-latitude range. On the other hand, within the range where a clear line of sight is maintained above the polar regions, communication with ground facilities is possible at all times, not limited to the LST time period. Therefore, by forming a circular communication network through communication with preceding and succeeding satellites, and having the satellite passing near the polar regions communicate with ground facilities on behalf of the network, continuous communication with ground facilities becomes possible.

[0147] The user satellite constitutes a projectile tracking system responsible for detecting and tracking projectile launches. Information from the user satellite needs to be rapidly transmitted in emergency situations. According to Example 1 of the satellite information transmission system 503, there is an effect of being able to quickly transmit satellite information to ground facilities installed in high-latitude zones via a circular communication network. The user satellites that make up the projectile tracking system include surveillance satellites equipped with infrared detection devices and a constellation of communication satellites formed in inclined orbits.

[0148] <Example configuration of Satellite Information Transmission System 503, Example 2> Figure 30 shows an example configuration of Example 2 of the satellite information transmission system 503 according to this embodiment. Figure 30 shows the satellite information transmission system 503 as viewed from the Arctic.

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

[0150] The first communications constellation 831 flies in an orbit above the equator. The first communications constellation 831 also forms a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane. The second communications constellation 832 will fly in a sun-synchronous orbit. Furthermore, the second communications constellation 832 will form a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane.

[0151] Each satellite in the first communications constellation 831 and the second communications constellation 832 is equipped with a second communications device for communication between the first communications constellation 831 and the second communications constellation 832. Each satellite in the first communications constellation 831 and the second communications constellation 832 transmits satellite information to ground facilities via the first communications constellation 831 and the second communications constellation 832.

[0152] Alternatively, each satellite in the first and second communication constellation may be equipped with communication devices for communicating with the user satellite. The user satellite may transmit satellite information to ground facilities via the first communications constellation 831 and the second communications constellation 832.

[0153] Satellite information acquired by satellites orbiting above the equator may be transmitted to ground facilities located in the mid-latitude and high-latitude regions. In such cases, it is reasonable for equatorial satellites, which form a circular communication network in the longitude direction, and sun-synchronous satellites, which form a circular communication network in the latitudinal direction, to communicate with each other. If ground facilities are located in high-latitude zones where a communication field of view can be maintained when a sun-synchronous satellite passes through the polar regions, then satellite information acquired by the equatorial satellite can be transmitted to the ground facilities in near real-time using only one sun-synchronous orbital plane. It goes without saying that the first communication constellation and the second communication constellation may each be equipped with communication devices for communicating with the user satellite.

[0154] <Example configuration of Satellite Information Transmission System 503, Example 3> Figure 31 is a diagram showing an example configuration of Example 3 of the satellite information transmission system 503 according to this embodiment. Figure 31 shows the satellite information transmission system 503 as viewed from the Arctic.

[0155] Example 3 of the satellite information transmission system 503 consists of a first communication constellation 831, a second communication constellation 832, a third communication constellation 833, and ground facilities.

[0156] The first communications constellation 831 flies in an orbit above the equator. The first communications constellation 831 also forms a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane. The second communications constellation 832 will fly in a sun-synchronous orbit. Furthermore, the second communications constellation 832 will form a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane. The third communications constellation 833 flies in an inclined orbit. Furthermore, the third communications constellation 833 forms a ring-shaped communications network with multiple satellites each equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane.

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

[0158] Each satellite in the first communications constellation 831, the second communications constellation 832, and the third communications constellation 833 transmits satellite information to ground facilities via at least two of the three communications constellations.

[0159] Alternatively, each satellite in the first communication constellation, the second communication constellation, and the third communication constellation 833 may be equipped with communication devices for communicating with the user satellite. The user satellite may transmit satellite information to ground facilities via at least two of the following: the first communication constellation 831, the second communication constellation 832, and the third communication constellation 833.

[0160] In some cases, satellite information acquired by equatorial orbiting satellites is transmitted to ground facilities located in the mid-latitude zone. In such cases, it is reasonable for inclined orbiting satellites that form a ring-shaped communication network in the longitude direction in the mid-latitude zone, equatorial orbiting satellites that form a ring-shaped communication network in the longitude direction, and sun-synchronous satellites that form a ring-shaped communication network in the latitudinal direction to communicate with each other.

[0161] For example, if ground equipment is located at 35 degrees north latitude, an inclined satellite with an orbital inclination of 35 degrees will fly above the ground equipment in the longitude direction, thus allowing for longer communication time with the ground equipment. If a group of inclined satellites has multiple orbital planes with normal vectors dispersed in the longitude direction, it will be possible to transmit satellite information acquired by satellites orbiting the equator to ground equipment in near real time.

[0162] <Example configuration of Satellite Information Transmission System 503, Example 4> Figure 32 shows an example configuration of Example 4 of the satellite information transmission system 503 according to this embodiment. Figure 32 shows the satellite information transmission system 503 as viewed from the Arctic.

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

[0164] The first communications constellation 831a flies in a sun-synchronous orbit. The first communications constellation 831a also forms a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane. The second communications constellation 832 flies in a different sun-synchronous orbit of the LST than the first communications constellation 831a. Furthermore, the second communications constellation 832 forms a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane.

[0165] Each satellite in the first communications constellation 831a and the second communications constellation 832 is equipped with a second communications device for communication between the first communications constellation 831a and the second communications constellation 832 when they pass near the polar regions. Each satellite in the first communications constellation 831a and the second communications constellation 832 transmits satellite information to ground facilities via the first communications constellation 831a and the second communications constellation 832.

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

[0167] <Example configuration of Satellite Information Transmission System 503, Example 5> Figure 33 is a diagram showing an example configuration of Example 5 of the satellite information transmission system 503 according to this embodiment. Figure 33 shows the satellite information transmission system 503 as viewed from above the equator.

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

[0169] The first communications constellation 831 flies in an orbit above the equator. The first communications constellation 831 also forms a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane. The second communications constellation 832a flies in an inclined orbit. The second communications constellation 832a also forms a ring-shaped communications network with multiple satellites equipped with a first communications device that communicates with satellites in front of and behind it in the direction of travel on the same orbital plane.

[0170] Each satellite in the first communications constellation 831 and the second communications constellation 832a is equipped with a second communications device for communication between the first communications constellation 831 and the second communications constellation 832a. Each satellite in the first communications constellation 831 and the second communications constellation 832a transmits satellite information to ground facilities via the first communications constellation 831 and the second communications 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. Furthermore, the time period during which 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 period when the second communication constellation 832a is composed of multiple orbital planes with different normal vectors.

[0172] As described in Embodiment 1, the satellites are controlled by commands transmitted from ground equipment. The ground equipment includes a satellite constellation formation unit in its processor, which forms a satellite constellation by communicating with each satellite. The satellites also have satellite constellation formation units, and the satellite constellation formation units of each of the multiple satellites work together with the satellite constellation formation unit of the ground equipment to control the satellite constellation. The satellite constellation formation unit of a satellite is, for example, provided in a satellite control device.

[0173] In embodiments 1 to 6 described above, each system and each device, such as the satellite monitoring system, satellite information transmission system, ground equipment, communication satellite, monitoring system, constituent satellites, communication satellite constellation, satellite constellation, artificial satellite, and satellite, was described as an independent functional block. However, the configuration of each system and each device does not have to be as described in the embodiments above. The functional blocks of each system and each device can have any configuration as long as they can realize the functions described in the embodiments above. Furthermore, each system and each device may be a single device or a system composed of multiple devices. Furthermore, multiple parts or embodiments from Embodiments 1 to 6 may be implemented in combination. Alternatively, only one part or embodiment from these embodiments may be implemented. In addition, these embodiments may be combined in any way, either as a whole or in part. In other words, in embodiments 1 to 6, it is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component in each embodiment.

[0174] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the Disclosure, the scope of the Applications of the Disclosure, or the scope of Uses of the Disclosure. The embodiments described above can be modified in various ways as needed. [Explanation of symbols]

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

Claims

1. Critical infrastructure, which is social infrastructure in outer space, is composed of a constellation of infrastructure satellites that fly in Earth orbit (LEO: Low Earth Orbit) at an altitude of 500 km to 2000 km, A constellation of monitoring satellites consisting of monitoring satellites that fly in orbits at an altitude of 2000 km or less to monitor the aforementioned infrastructure satellite constellation and perform on-orbit services, Ground equipment installed on the ground and used to exchange information with each of the infrastructure satellites in the aforementioned infrastructure satellite constellation, A monitoring center installed on the ground and which exchanges information with the aforementioned monitoring satellite. A satellite monitoring system equipped with, The aforementioned infrastructure satellite constellation includes a constellation of communication satellites, The aforementioned group of communications satellites is They fly in evenly spaced orbits with orbital altitudes and inclinations that result in sun-synchronous orbits that complete an integer number of orbits per day. In the aforementioned satellite monitoring system, the monitoring satellite and the monitoring center exchange information via the communication satellite constellation. The aforementioned communications satellite, A first communication device that communicates with the aforementioned ground equipment, Three second communication devices for communication between satellites and It is equipped with, The aforementioned group of communications satellites is A first satellite that communicates with the aforementioned ground equipment, A second satellite that communicates with the aforementioned monitoring satellite, A third satellite that will only communicate with satellites flying in front of and behind it, and Equipped with, A satellite monitoring system that uses the communication satellite as the first satellite, the second satellite, and the third satellite, to communicate with satellites flying in front of and behind it in the same orbital plane, and simultaneously communicates with the ground facilities and the monitoring satellite.

2. Critical infrastructure, which is social infrastructure in outer space, is composed of a constellation of infrastructure satellites that fly in Earth orbit (LEO: Low Earth Orbit) at an altitude of 500 km to 2000 km, Ground equipment installed on the ground and which exchanges information with each of the infrastructure satellites in the aforementioned infrastructure satellite constellation A satellite information transmission system comprising, The infrastructure satellite constellation consists of a communications satellite constellation comprising communications satellites and a user satellite constellation comprising user satellites that utilize the communications satellite constellation as a communication line. The aforementioned group of communications satellites is They fly in evenly spaced orbits with orbital altitudes and inclinations that result in sun-synchronous orbits that complete an integer number of orbits per day. In the aforementioned satellite information transmission system, the user satellite and the ground equipment exchange information via the communication satellite constellation. The aforementioned communications satellite, A first communication device that communicates with the aforementioned ground equipment, Three second communication devices for communication between satellites and It is equipped with, The aforementioned group of communications satellites is A first satellite that communicates with the aforementioned ground equipment, A second satellite that communicates with the aforementioned user satellite, A third satellite that will only communicate with satellites flying in front of and behind it, and Equipped with, A satellite information transmission system that uses the communication satellites as the first, second, and third satellites, respectively, to communicate with satellites flying in the same orbital plane, both in front of and behind the first satellite, and simultaneously communicates with the ground facilities and the user satellite.

Images