Satellite information transmission system, geostationary satellite, and ground facilities

Abstract

To always enable communication transfer between a monitor satellite and the ground at low cost.SOLUTION: A satellite information transmission system 500 includes a monitor satellite 300, a ground facility 700, and a plurality of geostationary satellites 400. The monitor satellite 300 monitors the earth or a space object while moving in a longitude direction in the vicinity of a geostationary orbit. The ground facility 700 gives and receives satellite information 200 to and from the monitor satellite. Each geostationary satellite 400 flies in the geostationary orbit and relays the communication of the satellite information 200 between the monitor satellite 300 and the ground facility 700. In the satellite information transmission system 500, optical communication is performed between the plurality of geostationary satellites 400, and radio wave communication is performed between the monitor satellite 300 and each geostationary satellite 400. Further, in the satellite information transmission system 500, radio wave communication is performed between each geostationary satellite 400 and the ground facility 700.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a satellite information transmission system, a geostationary satellite, and a ground facility. [Background technology]

[0002] In geostationary orbit, the orbital position where communication with the ground is permitted, the available frequency band, and the available transmission capacity are limited. Therefore, the locations where a surveillance satellite near a geostationary orbit can directly communicate with the ground and the communication performance are limited, and it may not be possible to respond to an emergency.

[0003] Patent Document 1 discloses a method for observing space debris on a geostationary satellite orbit. [Prior art documents] [Patent documents]

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

[0005] In Patent Document 1, there is a problem that, for a monitoring satellite that monitors space objects on a geostationary satellite, the area in which communication between the monitoring satellite and ground equipment is permitted may be limited.

[0006] The present disclosure aims to enable constant communication between a monitoring satellite and ground by transmitting satellite information from a monitoring satellite near a geostationary orbit to ground via a geostationary satellite that is permitted to communicate with ground facilities. [Means for solving the problem]

[0007] The satellite information transmission system according to the present disclosure includes: A monitoring satellite that monitors the Earth or space objects while moving in the longitude direction near a geostationary orbit; a ground facility for transmitting and receiving satellite information to and from the monitoring satellite; a plurality of geostationary satellites flying in geostationary orbits and relaying communication of satellite information between the monitoring satellites and the ground facilities; A satellite information transmission system comprising: optically communicating between the plurality of geostationary satellites; radio communication between the monitoring satellite and each of the plurality of geostationary satellites; Radio wave communication is performed between each of the plurality of geostationary satellites and the ground facility. Effect of the Invention

[0008] In the satellite information transmission system according to the present disclosure, a monitoring satellite near a geostationary orbit transmits satellite information to the ground via a geostationary satellite that is permitted to communicate with ground facilities. In addition, communication between the monitoring satellite and each of the multiple geostationary satellites is by radio communication. Therefore, the satellite information transmission system according to the present disclosure has the effect of enabling constant communication between the monitoring satellite and ground facilities at low cost. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a satellite information transmission system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a monitoring satellite according to the first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of a hardware configuration of the ground equipment according to the first embodiment. [Figure 4] FIG. 2 is a diagram showing monitoring from a high altitude during westward movement in the first example of the satellite information transmission system according to the first embodiment. [Diagram 5] FIG. 2 is a diagram showing monitoring from a low altitude during eastward movement in the first example of the satellite information transmission system according to the first embodiment. [Figure 6] FIG. 2 is a diagram showing an example of a detailed configuration of each satellite in the first embodiment of the satellite information transmission system according to the first embodiment. [Figure 7] FIG. 2 is a diagram showing an example of the configuration of a data relay satellite according to the first embodiment. [Figure 8]FIG. 2 is a diagram showing an example of the configuration of a meteorological satellite according to the first embodiment. [Figure 9] FIG. 11 is a diagram showing monitoring from a high altitude during westward movement in the second embodiment of the satellite information transmission system according to the first embodiment. [Figure 10] FIG. 11 is a diagram showing monitoring from a low altitude during eastward movement in the second embodiment of the satellite information transmission system according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] Embodiment 1 ***Configuration Description*** FIG. 1 is a diagram showing an example of the configuration of a satellite information transmission system 500 according to the present embodiment.

[0012] The satellite information transmission system 500 includes a monitoring satellite 300 , a plurality of geostationary satellites 400 , and ground equipment 700 .

[0013] The monitoring satellite 300 monitors the Earth or space objects while moving longitude-wise near the geostationary orbit. The ground equipment 700 is equipment installed on the ground. The ground equipment 700 transmits and receives satellite information 200 to and from the monitoring satellite 300. The geostationary satellite 400 flies in a geostationary orbit and relays communication of the satellite information 200 between the monitoring satellite 300 and the ground facility 700 . The satellite information 200 is information exchanged between the monitoring satellite 300 and the ground equipment 700 .

[0014] FIG. 2 is a diagram showing an example of the configuration of a monitoring satellite 300 according to this embodiment. The surveillance satellite 300 monitors an object such as the Earth or a space object. 1, the monitoring target monitored by the monitoring satellite 300 may include a geostationary satellite 400 in a geostationary orbit or a positioning satellite in a quasi-zenith orbit (QZO). QZO is an abbreviation for Quasi-Zenith Satellite orbit.

[0015] The monitoring satellite 300 includes a satellite communication device 31, a monitoring device 32, a propulsion device 33, an attitude control device , a satellite control device 35, and a power supply device .

[0016] The satellite communication device 31 is a communication device for communicating with the ground facility 700. For example, the satellite communication device 31 receives various commands from the ground facility 700. In addition, the satellite communication device 31 transmits monitoring data obtained by the monitoring device 32 to the ground facility 700. The various commands and monitoring data are examples of satellite information 200 .

[0017] The monitoring device 32 is a device for monitoring a monitoring target such as the Earth or a space object, and generates monitoring data. In this embodiment, the monitoring target may be referred to as a flying object. The monitoring device 32 is an infrared monitoring device that uses infrared rays. For example, the monitoring device 32 is an infrared monitoring device that is oriented toward the edge of the Earth. The monitoring satellite 300 has a pointing function for directing the line of sight toward the flying object.

[0018] The monitoring data is data corresponding to an image in which the flying object is captured, and indicates the position of the flying object within the field of view (monitoring range) of the monitoring device 32. The monitoring data may include time information, position information, line-of-sight information, and field-of-view information. The time information indicates the time when monitoring was performed (monitoring time). The position information indicates the coordinate values ​​of the monitoring satellite 300. The line-of-sight information indicates the line-of-sight direction of the monitoring device 32. The field-of-view information indicates the field of view of the monitoring device 32.

[0019] The propulsion device 33 is a device that provides thrust to the monitoring satellite 300 and changes the speed of the monitoring satellite 300. Specifically, the propulsion device 33 is an electric propulsion device. For example, the propulsion device 33 is an ion engine or a Hall thruster.

[0020] The attitude control device 34 is a device for controlling attitude elements such as the attitude of the monitoring satellite 300 and the angular velocity of the monitoring satellite 300 . The attitude control device 34 changes each attitude element to a desired direction. Alternatively, the attitude control device 34 maintains each attitude element in a desired direction. The attitude control device 34 includes an attitude sensor, an actuator, and a controller. The attitude sensor is a gyroscope, an earth sensor, a sun sensor, a star tracker, a thruster, a magnetic sensor, etc. The actuator is an attitude control thruster, a momentum wheel, a reaction wheel, and a control moment gyro. The controller controls the actuator according to the measurement data of the attitude sensor or various commands from the ground equipment 700. The attitude control device 34 can be used as a device (field of view direction changing device) for changing the field of view direction of the monitoring device 32. The field of view direction of the monitoring device 32 corresponds to the line of sight direction of the monitoring device 32. The range (field of view) centered on the line of sight direction of the monitoring device 32 becomes the monitoring range.

[0021] The satellite control device 35 is a computer and includes a processing circuit that controls each device of the monitoring satellite 300. For example, the satellite control device 35 controls each device in accordance with various commands transmitted from the ground facility 700.

[0022] The power supply unit 36 ​​includes a solar cell, a battery, a power control device, and the like, and supplies power to each device of the monitoring satellite 300 .

[0023] As shown in FIG. 1, geostationary satellites 400 flying in geostationary orbits are specifically satellites such as a communication satellite 401, a positioning satellite 402, a data relay satellite 403, a meteorological satellite 404, and an observation satellite 405. The configuration of these geostationary satellites 400 is similar to that of the monitoring satellite 300 described above, but each satellite is equipped with mission equipment for carrying out its own mission instead of the monitoring device 32. For example, the meteorological satellite 404 is equipped with meteorological observation equipment for observing the weather on Earth, in addition to the satellite communication device 31, the propulsion device 33, the attitude control device 34, the satellite control device 35, and the power supply device 36.

[0024] FIG. 3 is a diagram showing an example of a hardware configuration of the ground equipment 700 according to this embodiment. The hardware included in the computer will be described using the ground equipment 700 as an example.

[0025] The processor 910 is a device that executes a program that realizes the functions of the ground equipment 700 . The processor 910 is an IC that performs arithmetic processing. Specific examples of the processor 910 are a CPU, a DSP, and a GPU. IC is an abbreviation for Integrated Circuit. CPU is an abbreviation for Central Processing Unit. DSP is an abbreviation for Digital Signal Processor. GPU is an abbreviation for Graphics Processing Unit.

[0026] The memory 921 is a storage device that temporarily stores data. Specific examples of the memory 921 are SRAM and DRAM. SRAM is an abbreviation for Static Random Access Memory. DRAM is an abbreviation for Dynamic Random Access Memory.

[0027] The auxiliary storage device 922 is a storage device that stores data. A specific example of the auxiliary storage device 922 is a HDD. The auxiliary storage device 922 may also be a portable storage medium such as an SD (registered trademark) memory card, CF, NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, or a DVD. HDD is an abbreviation for Hard Disk Drive. SD (registered trademark) is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash (registered trademark). DVD is an abbreviation for Digital Versatile Disk.

[0028] The input interface 930 is a port connected to an input device such as a mouse, a keyboard, or a touch panel. Specifically, the input interface 930 is a USB terminal. The input interface 930 may be a port connected to a LAN. USB is an abbreviation for Universal Serial Bus. LAN is an abbreviation for Local Area Network. The output interface 940 is a port to which a cable of a display device 941 such as a display is connected. Specifically, the output interface 940 is a USB terminal or an HDMI (registered trademark) terminal. Specifically, the display is an LCD. HDMI (registered trademark) is an abbreviation for High Definition Multimedia Interface. LCD is an abbreviation for Liquid Crystal Display.

[0029] The communication device 950 includes a receiver and a transmitter. Specifically, the communication device 950 is a communication chip or a NIC. NIC is an abbreviation of Network Interface Card.

[0030] A program that realizes the functions of the ground equipment 700 is loaded into the processor 910 and executed by the processor 910. In addition to the program, an OS is also stored in the memory 921. The OS is an abbreviation for Operating System. The processor 910 executes the program while executing the OS. The program and the OS may be stored in an auxiliary storage device 922. The program and the OS stored in the auxiliary storage device 922 are loaded into the memory 921 and executed by the processor 910. Note that a part or all of the program that realizes the functions of the ground equipment 700 may be incorporated into the OS.

[0031] The ground equipment 700 may include multiple processors that replace the processor 910. These multiple processors share the task of executing a program. Each processor is a device that executes a program, just like the processor 910.

[0032] Data, information, signal values ​​and variable values ​​used, processed or output by the programs are stored in the memory 921, the secondary storage device 922, or in registers or cache memory within the processor 910.

[0033] The "parts" of the parts of the ground equipment 700 may be read as "processing," "procedure," "means," "steps," "circuitry," or "steps." Also, the "parts" of the parts of the ground equipment 700 may be read as "program," "program product," or "computer-readable recording medium on which a program is recorded." "Processing," "procedure," "means," "steps," "circuitry," or "steps" may be read as mutually interchangeable.

[0034] The ground equipment 700 generates various commands for each monitoring satellite 300 in order to control each monitoring satellite 300. The ground equipment 700 also analyzes monitoring data obtained from each monitoring satellite 300 and generates information (e.g., position information) of the flying object being monitored. The communication device 950 communicates with each monitoring satellite 300. Specifically, the communication device 950 transmits various commands to each monitoring satellite 300. In addition, the communication device 950 receives monitoring data transmitted from each monitoring satellite 300. In this embodiment, the communication device 950 communicates with each monitoring satellite 300 via a geostationary satellite 400 .

[0035] The processing circuits provided in the ground equipment 700 and the satellite control device 35 will now be described. The processing circuitry may be dedicated hardware or may be a processor executing a program stored in a memory as described above. In the processing circuit, some functions may be realized by dedicated hardware and the remaining functions may be realized by software or firmware, i.e., the processing circuit may be realized by hardware, software, firmware, or a combination thereof. The dedicated hardware may be, for example, a single circuit, multiple circuits, a programmed processor, parallel programmed processors, an ASIC, an FPGA, or a combination of these. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array.

[0036] The adjustment of satellite altitude and orbital inclination is explained. The relative angle of the normal to the orbital plane of the monitoring satellite 300 as viewed from the North Pole is determined by the correlation between the satellite altitude and the orbital inclination angle. By fine-tuning the orbital inclination angle appropriately under altitude conditions that maintain the number of satellite orbits per day, it is possible to operate the satellite constellation while maintaining the relative angle between the orbital planes. The ground facility 700 generates commands for controlling the altitude of each monitoring satellite 300. The ground facility 700 also generates commands for controlling the orbital inclination of each monitoring satellite 300. Then, the ground facility 700 transmits these commands to each monitoring satellite 300. In each monitoring satellite 300, the satellite control device 35 adjusts the satellite altitude and the orbital inclination angle according to these commands. Specifically, the satellite control device 35 controls the propulsion device 33 according to these commands. The propulsion device 33 can adjust the satellite altitude and the orbital inclination angle by changing the satellite speed. When the flight speed of the monitoring satellite 300 increases, the altitude of the monitoring satellite 300 increases. When the altitude of the monitoring satellite 300 increases, the ground speed of the monitoring satellite 300 decreases. When the flight speed of the monitoring satellite 300 slows down, the altitude of the monitoring satellite 300 descends. When the altitude of the monitoring satellite 300 descends, the ground speed of the monitoring satellite 300 increases. If the propulsion device 33 generates thrust in a direction perpendicular to the orbital plane at the point (equinox) where the monitoring satellite 300 crosses the equator, the orbital inclination angle can be effectively fine-tuned.

[0037] ***Functions of Satellite Information Transmission System 500*** In Figure 1, the communications represented by solid lines are optical communications, and the communications represented by dotted lines are radio communications. Among the multiple geostationary satellites 400, information is exchanged between them by optical communication. Information is exchanged between the monitoring satellite 300 and each of the multiple geostationary satellites 400 by radio wave communication. Between each of the multiple geostationary satellites 400 and the ground equipment 700, information is exchanged by radio wave communication.

[0038] The monitoring satellite 300 moves in the longitude direction to monitor the Earth or space objects. At this time, the area in which the monitoring satellite 300 is permitted to communicate with the ground facility 700 is limited. As shown in Fig. 1, in this embodiment, the monitoring satellite 300 always transmits the satellite information 200 via the geostationary satellite 400 that is permitted to communicate with the ground facility 700. This has the effect of making communication between the monitoring satellite 300 and the ground facility 700 possible at all times.

[0039] The means of communication between satellites can be selected from optical communication and radio communication. Optical communications has the advantage of being able to transmit large volumes of data and to realize secret communications. However, because optical communications requires that the optical axes of the transmitter and receiver be aligned with high precision, it is necessary to realize high-precision pointing control and high-precision pointing stability for the satellite carrying the communications equipment. Furthermore, it is essential to suppress disturbances that cause misalignment of the optical axis in optical communications. When one satellite is to communicate optically with multiple communication partners at the same time, it is necessary to perform highly accurate pointing control with all of the communication partners. In addition, since it is necessary to maintain highly accurate pointing stability during communication, there is an issue of high technical difficulty and high cost in maintaining and operating the satellite. Furthermore, if the optical axis becomes misaligned, communication will be interrupted, and it will be necessary to realign the optical axis, so there is a risk of communication being interrupted and it will take time to restore it.

[0040] In communications between multiple geostationary satellites, the relative positions of the geostationary satellites are maintained, making it easy to perform high-precision pointing control and maintain a high degree of pointing stability. On the other hand, in communications between a monitoring satellite and a geostationary satellite, which are in relative motion, it is necessary to change the pointing direction while keeping the optical axis aligned. In addition, when optical communications are used between geostationary satellites and ground equipment, there is the issue that communications may be cut off in the presence of clouds, and there is a high risk of communications being cut off in areas where ground equipment is installed that are highly likely to be covered by clouds.

[0041] <First embodiment of the satellite information transmission system 500> FIG. 4 is a diagram showing monitoring from a high altitude during westward movement in the first embodiment of the satellite information transmission system 500 according to the present embodiment. FIG. 5 is a diagram showing monitoring from a low altitude during eastward movement in the first embodiment of the satellite information transmission system 500 according to the present embodiment.

[0042] In the first embodiment of the satellite information transmission system 500, the multiple geostationary satellites 400 are made up of two meteorological satellites and two data relay satellites.

[0043] In the first embodiment of the satellite information transmission system 500, optical communication is limited to the means of communication between the geostationary satellites 400. For example, in FIG. 4, the communications between the data relay satellite A and the weather satellite B, between the weather satellite A and the weather satellite B, and between the weather satellite B and the data relay satellite A are optical communications. In FIG. 5, the communications between the data relay satellite A and the data relay satellite B, between the meteorological satellite A and the meteorological satellite B, and between the meteorological satellite B and the data relay satellite A are optical communications.

[0044] The monitoring satellite 300 and the geostationary satellite 400 communicate with each other via radio waves. For example, in FIG. 4, the communications between the data relay satellite A and the monitoring satellite 300, between the weather satellite A and the monitoring satellite 300, between the weather satellite B and the monitoring satellite 300, and between the data relay satellite B and the monitoring satellite 300 are radio wave communications. Also, in FIG. 5, the communications between the data relay satellite A and the monitoring satellite 300, between the weather satellite A and the monitoring satellite 300, between the weather satellite B and the monitoring satellite 300, and between the data relay satellite B and the monitoring satellite 300 are radio wave communications.

[0045] Radio communication is used between the geostationary satellite 400 and the ground equipment 700. For example, in FIG. 4, the communications between the data relay satellite A and the ground facility 700 and between the data relay satellite B and the ground facility 700 are radio wave communications. In FIG. 5, the communications between the data relay satellite A and the ground equipment 700, between the meteorological observation A and the ground equipment 700, and between the data relay satellite B and the ground equipment 700 are radio communications.

[0046] In FIG. 4, the communications between the meteorological satellite A and the ground equipment 700, and between the meteorological satellite B and the ground equipment 700, are radio communications for sending and receiving weather information. In FIG. 5, radio communication is performed between a meteorological satellite B capable of meteorological observation and ground equipment 700 to transmit and receive meteorological information.

[0047] As shown in FIGS. 4 and 5, combinations requiring high-precision pointing control of optical communications are limited to communications between geostationary satellites 400 .

[0048] FIG. 6 is a diagram showing an example of a detailed configuration of each satellite in the first embodiment of the satellite information transmission system 500 according to the present embodiment.

[0049] The geostationary satellite 400 includes a radio communication device 41 for transmitting and receiving information with the monitoring satellite 300, and an optical communication device 42 for transmitting and receiving information between a plurality of geostationary satellites. The geostationary satellite 400 also includes at least four radio communication devices 41 for transmitting and receiving information with the monitoring satellite 300, one on the west side toward the earth, one on the east side toward the earth, one on the west side toward the anti-earth, and one on the east side toward the anti-earth.

[0050] The optical communication device 42 in Fig. 6 is denoted as optical communication device (GEO-GEO) to indicate that the optical communication device is used between geostationary satellites flying in a geostationary orbit (GEO). GEO is an abbreviation for Geostationary Orbit. 6 includes radio communication device 41 (monitoring satellite-GEO), radio communication device (GEO-monitoring satellite), radio communication device (GEO-terrestrial), and radio communication device (terrestrial-GEO). The radio communication device (monitoring satellite-GEO) and the radio communication device (GEO-monitoring satellite) are communication devices used for radio communication between a monitoring satellite and a geostationary satellite. The radio communication device (GEO-terrestrial) and the radio communication device (terrestrial-GEO) are communication devices used for radio communication between a geostationary satellite and a ground facility.

[0051] The monitoring satellite 300 includes a radio communication device (monitoring satellite-GEO) that communicates with the geostationary satellite 400 via radio waves. The data relay satellite 403 includes a radio communication device (monitoring satellite-GEO) that communicates with the monitoring satellite 300 via radio waves, an optical communication device (GEO-GEO), and a radio communication device (GEO-terrestrial) that communicates with the ground facility 700 via radio waves. The meteorological satellite 404 includes meteorological mission equipment such as radio communication equipment (surveillance satellite-GEO), optical communication equipment (GEO-GEO), radio communication equipment (GEO-terrestrial), and meteorological observation equipment. The ground facility 700 includes a radio communication device (terrestrial-GEO) that communicates with the geostationary satellite 400 via radio waves.

[0052] The ground facilities 700 include ground facilities such as fixed base stations, a monitoring information center, and a weather information center. The ground equipment 700 may also include a moving body 600 . In the communication between the geostationary satellite 400 and the ground facility 700, the ground facility 700 may be a moving body 600. For example, the ground facility 700 is a moving body that takes direct action when an emergency response is required. If the ground facility 700 is such a moving body 600, there is an advantage that when the monitoring satellite 300 transmits information requiring an emergency response, the information can be exchanged with the moving body 600 in real time without delay. This has the effect of enabling rapid response actions, such as launching a rapid debris removal satellite, in the event of an emergency. An example of an emergency would be a situation in which a suspicious object, such as debris, approaches a domestic satellite.

[0053] 5, the monitoring satellite 300 monitors a space object in geostationary orbit while moving eastward from a low altitude relative to the geostationary orbit. At this time, it flies on the earth-pointing side of the geostationary satellite 400. Therefore, the communication device between the monitoring satellite 300 and the geostationary satellite 400 needs to secure a communication field of view on the earth-pointing side of the geostationary satellite 400. 4, the monitoring satellite 300 monitors space objects in geostationary orbit or the sunlit Earth surface while moving westward from a high altitude relative to the geostationary orbit. At this time, the monitoring satellite 300 flies on the opposite side to the Earth-pointing plane of the geostationary satellite 400. Therefore, the communication device between the monitoring satellite 300 and the geostationary satellite 400 needs to secure a communication field of view on the opposite side of the Earth-pointing plane of the geostationary satellite 400. In addition, it is necessary to be able to communicate with the monitoring satellite 300 both when it flies to the east of the geostationary satellite 400 and when it flies to the west of the geostationary satellite 400 .

[0054] In optical communications, communication is interrupted if there is an obstruction such as the structure, solar paddle, or antenna of the geostationary satellite 400. Therefore, in order to ensure optical communications visibility at high altitude, low altitude, eastward, and westward, four or more optical communications devices must be installed, which poses a problem of extremely high costs. If optical communication devices are placed at the end of a long boom and equipped with a function for changing the field of view over a large angle, the number of communication devices can be reduced. However, there is a problem in that it is difficult to achieve high-precision pointing accuracy and stability at the end of a long boom.

[0055] To address these issues with optical communication, if the monitoring satellite 300 and the geostationary satellite 400 communicate by radio waves and communicate in close proximity when passing nearby, a radio communication device using a small, lightweight, fixed antenna can be used. This has the effect of making it possible to provide four or more radio communication devices at low cost.

[0056] <Configuration example of data relay satellite 403> FIG. 7 is a diagram showing an example of the configuration of the data relay satellite 403 according to this embodiment.

[0057] As described above, in the first embodiment of the satellite information transmission system 500, the multiple geostationary satellites 400 are assumed to be two meteorological satellites 404 and two data relay satellites 403, totaling four satellites.

[0058] For the geostationary satellite 400, it is rational to deploy the solar paddles in the north-south direction to generate solar power. Therefore, the solar paddles are arranged in the north-south direction of the satellite, and are stored in a folded state like a folding screen when the satellite is launched. Therefore, the arrangement of other equipment on the north-south faces of the satellite is kept to a minimum.

[0059] Long-distance, large-capacity communications are carried out between the geostationary satellite 400 and the ground facility 700. For this purpose, radio communication antennas, which are large deployable antennas, are placed on the east and west sides. In the left diagram of Fig. 7, the radio communication device (GEO-terrestrial) is a radio communication antenna used for communication between the geostationary satellite 400 and the ground facility 700.

[0060] As for optical communication devices for communication between geostationary satellites, since the earth pointing direction is uniquely determined for the geostationary satellite 400, one set is placed on the earth pointing plane, or two sets, one each on the east and west sides of the earth pointing plane. The left diagram in FIG. 7 shows an example in which one optical communication device is arranged, and the right diagram in FIG. 7 shows an example in which two optical communication devices are arranged. The minimum required configuration is one set, and the advantage is that it can be implemented at low cost. On the other hand, if the communication targets on geostationary orbit exist on both the east and west sides, or if interference in the field of view of the onboard equipment cannot be avoided, it is reasonable to install two sets of optical communication devices. In addition, since there is almost no relative positional fluctuation in communications between geostationary satellites, it is not impossible to operate two sets of optical communication devices simultaneously on the east and west sides.

[0061] When installing one set of optical communication equipment at the center, a function for changing the optical axis direction by a large angle in the east-west direction is required. When installing two optical communication devices, it is reasonable to place one set with the optical axis line of sight vector tilted southward from the direction of the Earth, and the other set with the optical axis line of sight vector tilted northward from the direction of the Earth, since this ensures a wide field of view. Optical communication devices are usually equipped with a coarse-precision two-axis pointing direction changing device that changes the direction of the optical axis in the north-south and east-west directions, and a precision two-axis pointing direction device that controls the pointing of the optical axis with high precision.

[0062] The communication devices between the monitoring satellite 300 and the geostationary satellite 400 must be capable of radio communication even if the relative position of the monitoring satellite 300 moves over a large range in the longitude and altitude directions. Therefore, it is desirable to have a total of four sets of communication devices, one on the east-west side of the earth-pointing plane and one on the east-west side of the anti-earth-pointing plane, even in the minimum configuration. Furthermore, when increasing the number of monitoring satellites with which communication is performed simultaneously, or when there are restrictions on ensuring visibility, the operational restrictions can be reduced by appropriately increasing the number of radio communication devices installed. When the geostationary satellite 400 is a data relay satellite 403, it is reasonable to place the data relay satellite 403 away from the sky of Japan in the east-west direction. For this reason, it is also reasonable to mount the optical communication device located on the west side of the geostationary orbit on the east side of the satellite, and the optical communication device located on the east side on the west side of the satellite.

[0063] <Example of the configuration of the weather satellite 404> FIG. 8 is a diagram showing an example of the configuration of the meteorological satellite 404 according to this embodiment.

[0064] When the geostationary satellite 400 is a meteorological satellite 404, meteorological observation equipment is mounted on the earth-pointing plane. Therefore, in order to ensure a heat dissipation field of view, communication devices are arranged on the assumption that either the north or south direction of the earth-pointing plane will be occupied by the meteorological observation equipment. There are cases where the main purpose of the optical communication device installed on the meteorological satellite 404 is mutual information communication between two meteorological satellites, a master and a slave. In this case, it is reasonable to install the optical communication device on one of the two meteorological satellites on the eastern side and the other on the western side, depending on the geostationary orbital arrangement of the two meteorological satellites. In this case, the optical communication device can be used for communication between the meteorological satellite and the data relay satellite during the idle time when the meteorological satellites are not communicating with each other. In this case, the east-west position of the data relay satellite is limited to the data relay satellite located in the same direction as the meteorological satellite with which it is optically communicating.

[0065] <Second embodiment of satellite information transmission system 500> FIG. 9 is a diagram showing monitoring from a high altitude during westward movement in the second embodiment of the satellite information transmission system 500 according to the present embodiment. FIG. 10 is a diagram showing monitoring from a low altitude during eastward movement in the second embodiment of the satellite information transmission system 500 according to the present embodiment.

[0066] Regarding communication between the monitoring satellite 300 and the geostationary satellite 400, when the monitoring satellite 300 monitors while moving eastward, it flies at a lower altitude than the geostationary orbit. Also, when the monitoring satellite 300 monitors while moving westward, it flies at a higher altitude than the geostationary orbit. Therefore, with the earth pointing direction as viewed from the geostationary satellite 400 as the altitude direction, the radio communication device pointing eastward on the side of the earth pointing face and the radio communication device pointing westward communicate with the monitoring satellite 300 moving eastward. Also, in the geostationary satellite 400, the radio communication device pointing eastward on the side opposite to the earth pointing face and the radio communication device pointing westward communicate with the monitoring satellite 300 moving westward.

[0067] The monitoring satellite 300 is controlled to point at various angles in order to monitor various objects in space. Therefore, the monitoring satellite 300 is equipped with multiple radio communication devices, or when communicating with the geostationary satellite 400, the satellite is changed in pointing direction to ensure a radio communication field of view to carry out communication. When the monitoring satellite 300 monitors the Earth or objects in geostationary orbit with an optical monitoring device that utilizes solar reflection, it monitors while moving westward from a high altitude during the daytime on Earth, and monitors while moving eastward from a low altitude during the nighttime on Earth. When monitoring while moving eastward, the line-of-sight vector of the optical monitoring device is directed away from the Earth.

[0068] When the geostationary satellite 400 is a meteorological satellite 404, the meteorological observation equipment includes an infrared observation device. Therefore, meteorological observation can be performed even at night. For this reason, the meteorological satellite 404 occupies a radio communication device that transmits and receives meteorological satellite information to and from the ground facility 700 from daytime to nighttime. Therefore, in order to simultaneously relay data from the monitoring satellite 300, it is reasonable to have two sets of radio communication devices between the meteorological satellite 404 and the ground facility 700 and share them. In addition, in the meteorological satellite 404, it is necessary to prevent sunlight from entering the meteorological observation equipment before the sun enters the earth's shadow and after the sun leaves the earth's shadow. For this reason, there are time periods during which meteorological observation is suspended. If the radio communication device between the meteorological satellite 404 and the ground equipment 700 is reused during these time periods, it is possible to share a single set of radio communication device. This method has the effect of reducing the cost of the satellite information transmission system as a whole.

[0069] In addition, the two meteorological satellites 404 may be equipped with optical communication devices for the purpose of sharing information between them. In this case, the monitoring satellite 300 uses the idle time for communication to exchange meteorological information to exchange satellite information 200 with the meteorological satellite 404, and the meteorological satellite 404 exchanges satellite information with the ground equipment 700 via the data relay satellite 403. This allows the meteorological satellite 404 to play the role of data relay even during meteorological observation. Another advantage is that a constant communication environment can be established when one meteorological satellite passes close to the other. The purpose of information sharing between meteorological satellites may be to establish a backup system. In this case, there is a high possibility that the optical communication equipment can be used during the spare time of meteorological observations by the backup meteorological satellite. This has the effect of reducing the cost of the satellite information transmission system as a whole.

[0070] In the above-mentioned embodiment 1, the configuration of each system and each device, such as the satellite information transmission system and each satellite, does not have to be the same as the above-mentioned embodiment. The configuration of each system and each device may be any configuration as long as it can realize the functions described in the above-mentioned embodiment. Furthermore, it is acceptable to combine a plurality of parts or examples of the first embodiment. Alternatively, it is acceptable to implement only one part or example of this embodiment. In addition, it is acceptable to implement any combination of this embodiment as a whole or in part. That is, in the first embodiment, the embodiments can be freely combined, or any of the components in each embodiment can be modified, or any of the components in each embodiment can be omitted.

[0071] It should be noted that the above-described embodiment is essentially a preferred example, and is not intended to limit the scope of the present disclosure, the scope of application of the present disclosure, and the scope of use of the present disclosure. The above-described embodiment can be modified in various ways as necessary. [Explanation of symbols]

[0072] 200 satellite information, 300 monitoring satellite, 31 satellite communication device, 32 monitoring device, 33 propulsion device, 34 attitude control device, 35 satellite control device, 36 power supply device, 400 geostationary satellite, 401 communication satellite, 402 positioning satellite, 403 data relay satellite, 404 meteorological satellite, 405 observation satellite, 41 radio communication device, 42 optical communication device, 500 satellite information transmission system, 600 mobile body, 700 ground equipment, 910 processor, 921 memory, 922 auxiliary storage device, 930 input interface, 940 output interface, 950 communication device.

Claims

1. A monitoring satellite that monitors the Earth or space objects while moving in the longitude direction near a geostationary orbit; a ground facility for transmitting and receiving satellite information to and from the monitoring satellite; a plurality of geostationary satellites flying in geostationary orbits and relaying communication of satellite information between the monitoring satellites and the ground facilities; A satellite information transmission system comprising: The geostationary satellite is As radio wave communication devices for transmitting and receiving information with said monitoring satellites, four or more sets of radio wave communication devices are provided on the west side toward the earth, the east side toward the earth, the west side toward the opposite earth, and the east side toward the opposite earth, and an optical communication device is provided for transmitting and receiving information between said plurality of geostationary satellites; In an emergency response in which the monitoring satellite ascends or descends in altitude and deviates from the orbital position, the frequency band, and the transmission capacity in which communication with the ground is permitted, optically communicating between the plurality of geostationary satellites; radio communication between the monitoring satellite and each of the plurality of geostationary satellites; A satellite information transmission system for radio communication between each of the plurality of geostationary satellites and the ground facility.

2. A geostationary satellite constituting the satellite information transmission system according to claim 1, The radio communication device for transmitting and receiving information to and from the monitoring satellite; The optical communication device for transmitting and receiving information between the plurality of geostationary satellites; A geostationary satellite having:

3. A ground facility constituting the satellite information transmission system according to claim 1, Ground equipment that is mobile.

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