Data relay satellite

Abstract

To provide a data relay satellite that enables information transmission without communication interruption, with fewer communication satellites.SOLUTION: A flying-object handling system 700 causes a first data relay satellite 211 and a second data relay satellite 212 to cooperate with each other to transmit monitoring information to handling devices 310, 320. Each of the first data relay satellite 211 and the second data relay satellite 212 includes an optical communication device that changes a pointing direction by ±40 degrees around a +X axis with respect to a +Z axis and by ±40 degrees around a +Y axis facing a plus direction in right-hand orthogonal coordinates with respect to the +Z axis, wherein a +X axis direction facing the plus direction in the right-hand orthogonal coordinates is a satellite traveling direction +X of the data relay satellite and a +Z axis direction facing the plus direction in the right-hand orthogonal coordinates is a geocentric direction +Z of the satellite.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present disclosure relates to a monitoring system for monitoring the Earth, a satellite information transmission system for transmitting satellite information, a flying object corresponding system corresponding to a flying object, and a data relay device.

Background Art

[0002] Conventionally, there is a monitoring system using a satellite constellation (for example, Patent Document 1). In an inclined orbit constellation, there is an advantage that a system capable of constantly monitoring the mid-latitude zone with a small number of satellites can be constructed. In a monitoring satellite that is directed to the periphery of the Earth and detects and tracks the temperature after a flying object is launched, if there is a monitoring device that monitors the periphery of the Earth in a ring shape over the entire circumference with respect to the geocentric direction, it is possible to perform global monitoring with a small number of satellites.

[0003] In a new flying object called HGV (Hypersonic Guided Vehicle), in order to track after the end of injection at launch, detecting the heated airframe with infrared rays is an effective means. In this case, in order for the background signal not to become noise, monitoring the periphery of the Earth with the universe as the background is effective. In principle, the entire circumference can be monitored in a ring shape by a fish-eye camera, but there is a problem that the fish-eye camera has limitations such as spatial resolution and monitoring performance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a monitoring system capable of performing global constant monitoring with a small number of satellites and having high spatial resolution and monitoring performance.

Means for Solving the Problems

[0006] The data relay satellite according to the present disclosure is When the +X axis direction facing the plus direction in the right-handed orthogonal coordinates is set as the satellite traveling direction +X of the satellite, When the +Z axis direction facing the plus direction in the right-handed orthogonal coordinates is set as the geocentric direction +Z of the satellite, An optical communication device that changes the pointing direction by ±40 degrees around the +X axis with respect to the +Z axis and by ±40 degrees around the +Y axis facing the plus direction in the right-handed orthogonal coordinates with respect to the +Z axis, and transmits the monitoring information acquired by the monitoring satellite group to the countermeasure device in real time is provided.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to provide a data relay satellite that enables information transmission without communication interruption with a small number of communication satellites.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments 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.

[0010] Embodiment 1. ***Description of the Configuration***

[0011] In the following embodiments, the traveling direction and the geocentric direction of the satellite are defined as follows. The direction of the +X axis facing in the positive direction in the right-handed orthogonal coordinates is defined as the satellite traveling direction +X of the satellite. The direction of the +Z axis facing in the positive direction in the right-handed orthogonal coordinates is defined as the geocentric direction +Z of the satellite.

[0012] In the following embodiments, when referring to a sensor, it means an infrared sensor.

[0013] <Surveillance System 501: Inclined Orbit> The surveillance system 501 will be described with reference to FIGS. 1 to 7. In the surveillance system 501, the surveillance satellite 101 flies in an inclined orbit. FIG. 1 is a three - view of the surveillance satellite 101 included in the surveillance system 501. FIG. 2 is a view of the surveillance satellite 101 seen in the YZ plane. FIG. 3 shows the surveillance field of view when the surveillance satellite 101 flies northward over the equator. FIG. 4 shows the surveillance field of view when the surveillance satellite 101 flies southward over the equator. FIG. 5 shows the state where the surveillance satellite 101 is located over the equator and at the northernmost end of the orbital plane. FIG. 6 shows the state where a plurality of surveillance satellites 101 fly in each of two inclined orbits. FIG. 7 shows the relationship between the orbital altitude and latitude of the surveillance field of view directed to the periphery of the earth.

[0014] As shown in FIG. 6, the surveillance system 501 includes a plurality of surveillance satellites 101 and ground facilities 300. The ground facilities 300 described below receive the surveillance information acquired by the surveillance satellites from the surveillance satellites via relay satellites. As shown in FIG. 1, the surveillance satellite 101 has a first surveillance device 110 directed to the earth's surface and a second surveillance device 120 directed to the periphery of the earth. In the surveillance system 501, 12 or more surveillance satellites 101 form a satellite constellation by an inclined - orbit satellite group flying in an inclined orbit with an orbital inclination angle of 10 degrees or more and 80 degrees or less. As shown in FIG. 1, In the surveillance system 501, the second surveillance device 120 When the +X - axis direction in the right - hand orthogonal coordinate system, which is in the positive direction, is defined as the satellite traveling direction +X of the surveillance satellite 101, and the +Z - axis direction in the right - hand orthogonal coordinate system, which is in the positive direction, is defined as the geocentric direction +Z of the surveillance satellite 101, With respect to the +X - axis, around the +Z - axis, a +X + Y sensor 11S directed at +45 degrees, a +X - Y sensor 12S directed at -45 degrees, a -X + Y sensor 13S directed at +135 degrees, -X-Y sensor 14S pointing at -135 degrees, and has The second monitoring device 120 When flying northeast, monitors the high-latitude sky in the Northern Hemisphere with the +X-Y sensor 12S, monitors the high-latitude sky in the Southern Hemisphere with the -X+Y sensor 13S, When flying southeast, monitors the high-latitude sky in the Northern Hemisphere with the -X-Y sensor 14S, and monitors the high-latitude sky in the Southern Hemisphere with the +X+Y sensor 11S.

[0015] This will be specifically described below. The inclined orbit constellation has the advantage of being able to construct a system that can constantly monitor the mid-latitude zone with a small number of satellites. For a monitoring satellite that points to the periphery of the Earth and detects and tracks the temperature after the flying object is launched, if there is a monitoring device that monitors the periphery of the Earth in a ring shape over the entire circumference with respect to the geocentric direction, it is possible to monitor the entire globe with a small number of satellites. In a new flying object called HGV (Hypersonic Guided Vehicle), detecting the heated airframe with infrared rays is an effective means for tracking after the injection ends during launch. In order for the background signal not to become noise in the monitoring of HGV, monitoring the periphery of the Earth with the universe as the background is effective, and the second monitoring device 120 is a reasonable monitoring means. In principle, it is possible to monitor the entire circumference of the Earth in a ring shape with a fish-eye camera. However, there is a problem that there are limitations in the spatial resolution and monitoring performance of the fish-eye camera. Therefore, if a plurality of wide fields of view are used to ensure a monitoring field of view over the entire circumference with respect to the geocentric direction, the feasibility of realizing the spatial resolution and monitoring performance is increased. However, on the inclined orbit, there is a characteristic that the viewing direction of the monitoring device varies greatly when flying over the equator and at the northernmost or southernmost end of the orbital plane. Also, from the perspective of efficient utilization of satellite-generated power, it is reasonable to appropriately manage the overlapping areas of the viewing ranges of the satellite group forming the satellite constellation.

[0016] Therefore, in the monitoring system 501 of Embodiment 1, a second monitoring device 120 for monitoring the periphery of the Earth has an +X+Y sensor 11S that points +45 degrees around the +Z axis in the geocentric direction with respect to the satellite travel direction +X, an +X-Y sensor 12S that points -45 degrees, an -X+Y sensor 13S that points +135 degrees, and an -X-Y sensor 14S that points -135 degrees, for a total of four formulas. The second monitoring device 120 monitors the upper airspace of the high latitudes in the Northern Hemisphere with the +X-Y sensor 12S when flying northeastward, monitors the upper airspace of the high latitudes in the Southern Hemisphere with the -X+Y sensor 13S, monitors the upper airspace of the high latitudes in the Northern Hemisphere with the -X-Y sensor 14S when flying southeastward, and monitors the upper airspace of the high latitudes in the Southern Hemisphere with the +X+Y sensor 11S.

[0017] In FIG. 1, the monitoring fields of view 11 of the +X+Y sensor 11S, 12 of the +X-Y sensor 12S, 13 of the -X+Y sensor 13S, and 14 of the -X-Y sensor 14S are shown by dashed lines.

[0018] The first monitoring device 110 has a directly below monitoring sensor 15S that has a directly below monitoring field of view 15 directly below in the geocentric direction +Z. The monitoring field of view 15 of the directly below monitoring sensor 15S is shown by a dashed line.

[0019] In order to monitor the upper airspace of the high latitude regions or the equatorial upper airspace against the cosmic background, since there are limitations in the monitoring range for a polar orbiting satellite constellation or an equatorial upper airspace satellite constellation, a satellite constellation using an inclined orbit satellite constellation is advantageous. Also, for satellites flying in formation in the same orbital plane, there is a lot of overlap in the field of view between the forward field of view and the rear field of view. Therefore, in the monitoring system 501, as shown in the XY coordinates of FIG. 1, the monitoring field of view of the second monitoring device 120 of the four-mode is inclined by approximately 45 degrees from the satellite traveling direction +X. This reasonably realizes high-latitude upper-air monitoring such as in the polar regions and equatorial upper-air monitoring, and can save satellite resources in latitude bands with a lot of overlap. In the inclined orbit, a satellite flying northeast over the equator changes its flying direction to southeast after flying east at the northernmost end of the orbital plane. Similarly, a satellite flying southeast over the equator changes its flying direction to northeast after flying east at the southernmost end of the orbital plane. For this reason, the viewing direction of the second monitoring device 120 of the four-mode varies greatly with respect to the east-west-north-south direction. As shown in FIG. 3, when the monitoring satellite 101 passes over the equator in the northeast direction, the +X-Y sensor 12S pointing at -45 degrees monitors the upper air from the mid-latitudes to the high latitudes in the Northern Hemisphere. As shown in FIG. 4, when the monitoring satellite 101 passes over the equator in the southeast direction, the -X-Y sensor 14S pointing at -135 degrees monitors the upper air from the mid-latitudes to the high latitudes in the Northern Hemisphere. Similarly, as shown in FIG. 3, when the monitoring satellite 101 passes over the equator in the northeast direction, the -X+Y sensor 13S pointing at +135 degrees monitors the upper air from the mid-latitudes to the high latitudes in the Southern Hemisphere. As shown in FIG. 4, when the monitoring satellite 101 passes over the equator in the southeast direction, the +X+Y sensor 11S pointing at +45 degrees monitors the upper air from the mid-latitudes to the high latitudes in the Southern Hemisphere.

[0020] Needless to say from FIGS. 3 and 4, when only the Northern Hemisphere is the monitoring target, it may be sufficient to install only the +X-Y sensor 12S pointing at -45 degrees and the -X-Y sensor 14S pointing at -135 degrees. Also, by simultaneously monitoring a flying object from a plurality of monitoring satellites, it becomes possible to measure the orbital position based on the principle of space triangulation, and the more monitoring satellites are simultaneously monitoring, the higher the measurement accuracy. For this reason, by operating the second monitoring device 120 of the four-mode simultaneously on each monitoring satellite 101, there is an effect that high-precision monitoring is possible in a wide monitoring area. Also, when the monitoring area is limited, by operating only the sensors with high monitoring effects, there is an effect that satellite resources such as power can be saved.

[0021] <Peripheral Monitoring> This will be described with reference to FIG. 7. When performing earth peripheral monitoring from an orbital altitude of 1000 km, if the line-of-sight vector is inclined 30 degrees in the Elevation direction with respect to the north direction of the north-south axis, it will point in the tangential direction near 30 degrees north latitude. When performing earth peripheral monitoring from an orbital altitude of 2000 km, if the line-of-sight vector is inclined 40 degrees in the Elevation direction with respect to the north direction of the north-south axis, it will point in the tangential direction near 40 degrees north latitude. Therefore, if the line-of-sight vector of the second monitoring device 120 has a field-of-view range of Elevation 20 degrees to 40 degrees with respect to the XY plane, earth peripheral monitoring can be performed from a monitoring satellite with an orbital altitude of 1000 km to 2000 km. 20deg and 40deg shown in the XZ plane diagram of FIG. 1 indicate this field-of-view range.

[0022] <Monitoring System 502: Orbit over the Equator> FIG. 8 is a four-view diagram of the monitoring satellite 102 included in the monitoring system 502. The monitoring system 502 will be described with reference to FIG. 8.

[0023] The monitoring system 502 includes a plurality of monitoring satellites 102 having a first monitoring device 110 directed at the earth's surface and a second monitoring device 120 directed at the earth's periphery, and ground facilities 300. Six or more monitoring satellites 102 form a satellite constellation by an equatorial orbit satellite group flying in an equatorial orbit with an orbital inclination angle of 10 degrees or less. The monitoring system 502 includes ground facilities 300 as in FIG. 6. As shown in FIG. 8, in the monitoring system 502, the second monitoring device 120 when the direction of the +X axis, which points in the positive direction in the right-handed Cartesian coordinates, is the satellite travel direction +X of the monitoring satellite 102, and the direction of the +Z axis, which points in the positive direction in the right-handed Cartesian coordinates, is the geocentric direction +Z of the monitoring satellite 102, has a +Y sensor 21S that points +90 degrees around the +Z axis with respect to the +X axis, and a -Y sensor 22S that points -90 degrees. The second monitoring device The +Y sensor 21S monitors the upper air in the mid-latitudes of the southern hemisphere, and the -Y sensor 22S monitors the upper air in the mid-latitudes of the northern hemisphere.

[0024] In Fig. 8, the monitoring fields of view 21 of the +Y sensor 21S and 22 of the -Y sensor 22S are shown by dashed lines.

[0025] The first monitoring device 110 has a downward monitoring sensor 23S having a downward monitoring field of view 23 directly below in the geocentric direction +Z. The monitoring field of view 23 of the downward monitoring sensor 23S is shown by a dashed line.

[0026] It goes without saying that when only the northern and southern hemispheres or only the northern hemisphere are to be monitored, only one of the +Y sensor 21S pointing to +90 degrees and the -Y sensor 22S pointing to -90 degrees may be mounted.

[0027] <Monitoring System 503: Polar Orbit> Fig. 9 is a four-view diagram of the monitoring satellite 103 included in the monitoring system 503. The monitoring system 503 will be described with reference to Fig. 9.

[0028] The monitoring system 503 includes a plurality of monitoring satellites 103 having a first monitoring device 110 pointing to the Earth's surface and a second monitoring device 120 pointing to the Earth's periphery, a ground facility 300, and is provided with. Six or more monitoring satellites 103 form a satellite constellation by a group of polar orbit satellites flying in a polar orbit with an orbital inclination angle of 80 degrees or more. The monitoring system 503 is provided with a ground facility 300 in the same manner as in Fig. 6. The monitoring satellite 103 flies in a dawn-dusk orbit of a sun-synchronous orbit. The second monitoring device 120 When the direction of the +X axis in the positive direction in the right-handed rectangular coordinates is the satellite traveling direction +X of the monitoring satellite 103, and the direction of the +Z axis in the positive direction in the right-handed rectangular coordinates is the geocentric direction +Z of the monitoring satellite, a +X sensor 31S pointing in the direction of the +X axis, around the +Z axis with respect to the +X axis, a +Y sensor 32S pointing to +90 degrees, -Y sensor 33S that points at -90 degrees, has. The second monitoring device 120 monitors the +X axis direction with the +X sensor 31S, monitors the upper airspace of the eastern hemisphere of the Earth with the +Y sensor 32S, and monitors the upper airspace of the western hemisphere of the Earth with the -Y sensor 33S.

[0029] In FIG. 9, the monitoring fields of view 31 of the +X sensor 31S, 32 of the +Y sensor 32S, and 33 of the -Y sensor 33S are shown by dashed lines.

[0030] The first monitoring device 110 has a direct-down monitoring sensor 34S that has a direct-down monitoring field of view 34 directly below in the geocentric +Z direction. The monitoring field of view 34 of the direct-down monitoring sensor 34S is shown by a dashed line. Note that the monitoring satellite 103 shown in FIG. 9 is equipped with a communication device 41C. The communication device 41C will be described later.

[0031] In a polar orbit, since the monitoring satellite 103 passes through the polar regions every week, the monitoring system 503 can ensure the coverage of the monitoring network in the high-latitude regions even over the entire orbital plane. The monitoring satellite that generates electricity using solar cells can fly in a polar orbit called dawn-dusk, enabling the monitoring system 503 to have the fixed solar cell paddles always pointing at the sun while flying.

[0032] <Communication device 41C> The monitoring satellites 101, 102, and 103 are equipped with a communication device 41C. FIG. 10 shows the monitoring satellite 101 equipped with the communication device 41C. FIG. 11 shows the monitoring satellite 102 equipped with the communication device 41C. FIG. 12 shows the monitoring satellite 103 equipped with the communication device 41C. FIGS. 10 to 12 show the communication field of view 41 of the communication device 41C. Hereinafter, when the monitoring satellites 101, 102, and 103 are not distinguished, they are denoted as the monitoring satellite 100.

[0033] As shown in FIGS. 10 to 12, the monitoring satellite 100 has a communication device 41C. The communication device 41C has a communication field of view 41 of ±60 degrees or more around the +X axis with respect to the +Z axis, and has a communication field of view 41 of ±60 degrees or more around the +Y axis with respect to the +Z axis. The communication device 41C directly transmits the monitoring information acquired by the monitoring satellite 100 to the ground facility 300, or transmits it to the ground facility 300 via a communication satellite that relays the satellite information. The communication satellite will be described later.

[0034] The satellite constellation formed by the plurality of monitoring satellites 100 included in the monitoring system 501, the monitoring system 502, or the monitoring system 503 is formed at an orbital altitude of 1000 km or more. The monitoring satellite 100 forming the satellite constellation is a transmission system formed at an orbital altitude of 800 Km or less, and transmits the acquired monitoring information to the ground facility 300 via a satellite information transmission system that relays and transmits the satellite information between the monitoring satellite 100 and the ground facility 300. The satellite information transmission system will be described later. The satellite constellation has the advantage that the transmission delay is less at lower altitudes. There is a known concept of forming a satellite information transmission system at an orbital altitude of 300 km to 700 km. Even if the orbital altitude of the monitoring system having a communication field of view on the Earth-facing side of the monitoring satellite is about 1000 km, the monitoring information can be transmitted via a satellite information transmission system with an orbital altitude of 800 km or less.

[0035] Or, it may be as follows. The satellite constellation formed by the plurality of monitoring satellites 100 included in the monitoring system 501, the monitoring system 502, or the monitoring system 503 is formed at an orbital altitude of 1200 km or more. The monitoring satellite 100 forming the satellite constellation is a transmission system formed at an orbital altitude of 1000 km or less, and transmits the acquired monitoring information to the ground facility 300 via a satellite information transmission system that relays and transmits the satellite information between the monitoring satellite 100 and the ground facility 300. A satellite constellation has the advantage that a wider field of view can be ensured with fewer satellite numbers at higher altitudes. On the other hand, there is a known concept of forming a satellite information transmission system near an orbital altitude of 1000 km. If the orbital altitude of a monitoring system having a communication field of view on the Earth-facing side of a monitoring satellite is 1200 km or more, monitoring information can be transmitted via the satellite information transmission system near an orbital altitude of 1000 km.

[0036] <Satellite information transmission system 600> Referring to FIGS. 13 to 17, the satellite information transmission system 600 will be described. FIG. 13 is a four-view diagram of a communication satellite 201 included in the satellite information transmission system 600. The communication satellite 201 is provided with a communication device 55C for communicating with a monitoring satellite in the anti-Earth direction. In the two XY coordinate diagrams of FIG. 13, communication devices on the back side that are not actually visible are indicated by white circles, and communication devices that actually exist are indicated by black circles. In FIG. 13, two communication devices are arranged on the Earth-side surface, and three communication devices are arranged on the anti-Earth-side surface. FIG. 14 is a four-view diagram of a communication satellite 202 included in the satellite information transmission system 600. The meaning of the black and white circles in FIG. 14 is the same as that in FIG. 13. In FIG. 14, a communication device 56C for communicating with ground facilities 300 is arranged on the surface facing the Earth side. FIG. 15 shows that the satellite information transmission system 600 transmits satellite information of the monitoring system 501. FIG. 16 shows that the satellite information transmission system 600 transmits satellite information of the monitoring system 502. FIG. 17 shows that the satellite information transmission system 600 transmits satellite information of the monitoring system 503.

[0037] Referring to FIG. 13, communication satellite 201 will be described. In satellite information transmission system 600, communication satellites having an inter-satellite communication device for communicating between satellites and a terrestrial communication device for communicating with terrestrial equipment 300 fly while being arranged in eight or more on the same orbital plane. More specifically, communication satellites having an inter-satellite communication device and a terrestrial communication device fly in a substantially uniform arrangement of eight or more on the same orbital plane. Then, by arranging eight or more orbital planes in the longitudinal direction, a plurality of communication satellites form a satellite constellation. More specifically, eight or more orbital planes are arranged substantially uniformly in the longitudinal direction. Substantially uniform arrangement in the longitudinal direction means that, taking the rotation axis corresponding to the virtual NS axis connecting the North Pole and the South Pole as the rotation axis, there are eight or more orbital planes obtained by rotating one orbital plane, and these orbital planes are arranged at substantially equal intervals. The eight or more orbital planes are inclined orbits. One or more communication satellites, which are communication satellite 201, The direction of the +X axis facing in the positive direction in the right-handed Cartesian coordinates is defined as the satellite traveling direction +X of communication satellite 201, When the direction of the +Z axis facing in the positive direction in the right-handed Cartesian coordinates is defined as the geocentric direction +Z of communication satellite 201, When passing northward above the equator, A first optical communication device 51C for optical communication with a satellite in front of the flying direction on the same orbital plane, A second optical communication device 52C for optical communication with a satellite behind the flying direction on the same orbital plane, With respect to the +Y axis facing in the positive direction in the right-handed Cartesian coordinates, a third optical communication device 53C for optical communication with a satellite flying in the northeast (+X+Y) of the adjacent orbit on the east side (+Y direction), A fourth optical communication device 54C for optical communication with a satellite flying in the southwest (-X-Y) of the adjacent orbit on the west side (-Y), A communication device 55C, which is an inter-monitoring communication device for communicating with monitoring satellite 100 while pointing in the opposite direction (-Z) of the direction of the +Z axis, It has. The Azimuth communication field of view of the third optical communication device 53C is ±90 degrees or more with respect to the direction of the +X axis. The Azimuth communication field of view of the fourth optical communication device 54C is ±90 degrees or more with respect to the opposite direction of the +X axis. The communication field of view of the communication device 55C with the monitoring satellite 100 is ±60 degrees or more around the +X axis and ±60 degrees or more around the +Y axis with respect to the opposite direction of the +Z axis. FIG. 13 shows the communication field of view of each communication device. The symbol of the communication field of view is the number obtained by removing the letter C from the symbol of the communication device.

[0038] <Communication satellite 202> Also, the satellite information transmission system 600 includes a communication satellite 202 shown in FIG. 14. The communication satellite 202 is different from the communication satellite 201 in that the point where the communication device 56C is arranged on the earth side surface. The communication device 56C in FIG. 14 is directed in the direction of the +X axis and communicates with the ground facility 300. FIG. 14 shows the communication field of view of each communication device. The symbol of the communication field of view is the number obtained by removing the letter C from the symbol of the communication device. The communication device 56C has a communication field of view 56 with the ground facility 300 that is ±60 degrees or more around the +X axis with respect to the +Z axis and ±60 degrees or more around the +Y axis with respect to the +Z axis.

[0039] In the above description, it has been described that the communication satellite 201 includes the communication device 55C and the communication satellite 202 includes the communication device 56C, but both the communication satellite 201 and the communication satellite 202 may include the communication device 55C and the communication device 56C.

[0040] <Transmission of monitoring information in the monitoring system 501> Referring to FIG. 15. The satellite information transmission system 600 shows communication satellites 201, 202, and 203. The communication satellite 203 does not have the communication device 55C with respect to the communication satellite 201. It shows a situation where the monitoring information acquired by the monitoring satellite 101 is transmitted in the order of the communication satellite 201, the communication satellite 203, the communication satellite 202, and the ground facility 300 of the earth 400.

[0041] <Transmission of monitoring information in the monitoring system 502> Describe FIG. 16. The satellite information transmission system 600 shows communication satellites 201, 202, and 203. It shows the situation where the monitoring information obtained by the monitoring satellite 102 is transmitted in the order of communication satellite 201, communication satellite 203, communication satellite 202, and ground facility 300.

[0042] <Transmission of Monitoring Information in Monitoring System 503> Describe FIG. 17. The satellite information transmission system 600 shows communication satellites 201, 202, and 203. The monitoring information obtained by the monitoring satellite 103 over the North Pole is transmitted to the communication satellite 201 at the North Pole position and the ground facility 300. The monitoring information obtained by the monitoring satellite 103 located on the right side of the monitoring satellite 103 over the North Pole is transmitted to the communication satellite 201, communication satellite 202, and ground facility 300.

[0043] ***Effect of Embodiment 1*** According to the monitoring system of Embodiment 1, it is possible to perform global constant monitoring with a small number of satellites, and it is possible to provide a monitoring system with high spatial resolution and monitoring performance. Also, according to the satellite information transmission system of Embodiment 1, the monitoring information obtained by the monitoring satellite 100 can be efficiently transmitted to the ground facility 300.

[0044] Embodiment 2. Describe Embodiment 2 with reference to FIGS. 18 to 40. Embodiment 2 relates to a flying object response system 700. The flying object response system 700 is a form in which the monitoring system of Embodiment 1 and the satellite information transmission system are integrated. FIG. 18 shows the flying object response system 700.

[0045] As shown in FIG. 18, the flying object response system 700 includes a first data relay satellite 211 flying over the equator at an orbital altitude of 2000 km or more, a second data relay satellite 212 flying on a polar orbit at an orbital altitude of 2000 km or more, a plurality of monitoring satellites 100 flying at an orbital altitude of 2000 km or less, a countermeasure device 310 moving in the airspace or on land or at sea in the atmosphere, and a countermeasure device 320 fixed on the ground. A group of monitoring satellites, which are a plurality of monitoring satellites 100, acquire monitoring information of a flying object 333 that is launched from the ground and flies, and transmit the monitoring information to coping devices 310 and 320 via data relay satellites 211 and 212. The coping devices 310 and 320 perform coping actions on the flying object 333 using the transmitted monitoring information.

[0046] The flying object response system 700 includes three or more first data relay satellites 211 and three or more second data relay satellites 212. The first data relay satellites 211 and the second data relay satellites 212 are communication satellites.

[0047] In the flying object response system 700, optical communication 71 and radio communication 72 are performed. The optical communication 71 and the radio communication 72 shown in FIG. 18 are examples. Combinations of the optical communication 71 and the radio communication 72 are variations such as the following (1) to (4), for example. (1) At least one of the combinations of the first data relay satellites 211 with each other, the combinations of the second data relay satellites 212 with each other, and the combinations of the first data relay satellites 211 and the second data relay satellites 212 performs optical communication 71.

[0048] (2) The data relay satellites 211 and 212 and the monitoring satellite 100 perform radio communication 72, and the data relay satellites 211 and 212 and the coping devices 310 and 320 perform radio communication 72. FIG. 19 shows the state of the radio communication 72. From the left side of the figure, the data relay satellite 212 and the monitoring satellite 100 perform radio communication 72, the data relay satellite 212 and another monitoring satellite 100 perform radio communication 72, the data relay satellite 211 and the monitoring satellite 100 perform radio communication 72, and the first data relay satellite 211 and the coping device 310 perform radio communication 72.

[0049] (3) The data relay satellites 211 and 212 and the monitoring satellite 100 perform radio communication, the data relay satellites 211 and 212 and the coping devices 310 and 320 perform optical communication, and the coping devices 310 and 320 transmit monitoring information via a communication line 330. The communication line 330 will be described later with reference to FIG. 20. Fig. 20 shows transmission using optical communication 71, radio communication 72, and communication line 330. From the left side of the figure, a data relay satellite 212 and a monitoring satellite 100 perform radio communication 72, a data relay satellite 212 and another monitoring satellite 100 perform radio communication 72, and a data relay satellite 211 and a monitoring satellite 100 perform radio communication 72. A first data relay satellite 211 performs optical communication 71 with a handling device 320 and a second data relay satellite 212. In Fig. 20, a plurality of handling devices 320 are connected by communication lines 330. The handling devices 320 can exchange data with each other via the communication lines 330.

[0050] (4) The data relay satellites 211 and 212 and the monitoring satellite 100 communicate optically, the data relay satellites 211 and 212 and the countermeasures devices 310 and 320 communicate optically, and the countermeasures devices 310 and 320 transmit monitoring information to each other via a communication line 330 .

[0051] <Azimuth及びElevationの変更> 21 shows the range of change of the communication field of view of Azimuth and Elevation of the optical communication device 220C equipped on the data relay satellites 211 and 212. At least one of the first data relay satellite 211 and the second data relay satellite 212 As shown in FIG. The optical communication device 220C is The direction of the +X axis in the right-handed Cartesian coordinate system is the satellite direction of travel of the data relay satellite +X. If the direction of the +Z axis pointing in the positive direction in a right-handed Cartesian coordinate system is defined as the geocentric direction +Z of the data relay satellite, the communication field of view direction can be changed by 360 degrees in the Azimuth (XY plane) relative to the direction of the +Z axis, and by 0 degrees to 80 degrees in the +Z axis direction relative to the +X axis. Figure 21 shows this change range 221. The triangular area 222 on the left side is the state in which the change range 221 is rotated around the +Z axis. In other words, the area 222 shows the change state of the Azimuth (XY plane) of the change range 221. As shown in Figure 21, the ability to change the Azimuth and elevation enables the data relay satellites 211, 212 to perform optical communication with distant satellites relative to the Earth 400.

[0052] Figure 22 shows the effect of the changeability of the communication field of view of the optical communication device 220C between the data relay satellite 211 and the second data relay satellite 212. Region 223 shows the region obtained by rotating the Elevation change range shown in FIG. 21 in the Azimuth direction. The first data relay satellite 211 can perform optical communication with the distant second data relay satellite 212A by changing the communication field of view direction. The second data relay satellite 212 can perform optical communication with the distant second data relay satellite 212B by changing the communication field of view direction. Figure 23 shows the change of the communication field of view of the optical communication device 220C from the first data relay satellite 211, which is a geostationary satellite, to the second data relay satellite 212, which is a polar orbiting satellite. The region 225 indicating the communication field of view may be rotated around the Azimuth direction, that is, the +Z axis, which is the geocentric direction, after changing the Elevation. FIG. 23 shows the effect of the communication field of view due to the change of the communication field of view.

[0053] Figure 24 shows that the communication field of view direction can be changed by 360 degrees in the Azimuth (XY plane) with respect to the +Z axis direction and by 0 degrees to 70 degrees in the Elevation with respect to the +X axis direction with respect to FIG. 22. Figure 25 shows that the communication field of view direction can be changed by 360 degrees in the Azimuth (XY plane) with respect to the +Z axis direction and by 0 degrees to 60 degrees in the Elevation with respect to the +X axis direction with respect to FIG. 22. Since FIGS. 24 and 25 are the same as FIG. 22, the description is omitted.

[0054] Figure 26 relates to the communication device 230C provided in the first data relay satellite 211 and the second data relay satellite 212. At least one of the first data relay satellite 211 and the second data relay satellite 212 is provided with the communication device 230C. The communication device 230C in FIG. 26 is in the direction of the +X axis, which is the positive direction in the right-handed orthogonal coordinates, as the satellite traveling direction +X of the data relay satellite, When the +Z axis direction, which points in the positive direction in the right-handed Cartesian coordinates, is set as the geocentric direction +Z of the data relay satellite, with respect to the +Z axis, it can be rotated by ±10 degrees around the +X axis, and, with respect to the +Z axis, the viewing direction can be changed by ±10 degrees around the +Y axis, which points in the positive direction in the right-handed Cartesian coordinates. The flying object corresponding system 700 communicates with a coping device 310 moving in the airspace, on land, or on the sea of the atmosphere or a coping device 320 fixed on the ground using the communication device 230C. With respect to the +Z axis, rotating by ±10 degrees around the +X axis and rotating by ±10 degrees around the +Y axis with respect to the +Z axis means that in the case of the first data relay satellite 211 in FIG. 26, rotating by ±10 degrees around the +X axis with respect to the +Z axis changes the communication viewing angle by ±10 degrees in the longitudinal direction of the earth 400, and rotating by ±10 degrees around the +Y axis with respect to the +Z axis changes the communication viewing angle by ±10 degrees in the horizontal direction of the earth 400. FIG. 26 shows communication viewing fields 231 and 232 that change within a range of ±10 degrees.

[0055] FIG. 27 shows that, compared with FIG. 26, the communication device 230C can change the communication viewing field by ±20 degrees around the +X axis with respect to the +Z axis and by ±20 degrees around the +Y axis with respect to the +Z axis. FIG. 28 shows that, compared with FIG. 26, the communication device 230C can change the communication viewing field by ±30 degrees around the +X axis with respect to the +Z axis and by ±30 degrees around the +Y axis with respect to the +Z axis. Since FIGS. 27 and 28 are the same as FIG. 26, the description is omitted.

[0056] The flying object corresponding system 700 described in FIG. 18 may also have the following configuration. The flying object corresponding system 700 includes a first data relay satellite 211 flying over the equator at an orbital altitude of 2000 km or more, a second data relay satellite 213 which is a sun-synchronous orbit satellite flying in a sun-synchronous orbit, a plurality of monitoring satellites 100 flying at an orbital altitude of 2000 km or less, a countermeasure device 310 moving in the airspace, on land, or on the sea of the atmosphere, and a countermeasure device 320 fixed on the ground. The group of monitoring satellites 100, which are a plurality of monitoring satellites, acquire monitoring information of the flying object 333 launched from the ground and flying, and transmit the monitoring information to the countermeasure devices 310 and 320 via the data relay satellites 211 and 213. The countermeasure devices 310 and 320 perform countermeasure actions against the flying object 333 using the transmitted monitoring information.

[0057] The flying object corresponding system 700 described in FIG. 18 may also have the following configuration. In the flying object corresponding system 700, the monitoring satellite 100 includes a first monitoring device 110 directed at the Earth's surface and a second monitoring device 120 directed at the Earth's periphery. Six or more monitoring satellites 100 form a group of polar orbit satellites flying at an orbital inclination angle of 80 degrees or more. Twelve or more monitoring satellites 100 form a group of inclined orbit satellites flying in an inclined orbit with an orbital inclination angle of 10 degrees or more and 80 degrees or less. Six or more monitoring satellites 100 form a group of equatorial upper atmosphere satellites flying over the equator with an orbital inclination angle of less than 10 degrees.

[0058] The flying object corresponding system 700 described in FIG. 18 may also include the following data relay satellite. The flying object corresponding system 700 may include a data relay satellite equipped with two optical communication devices capable of changing the pointing direction by an Elevation rotation angle of 60 degrees or more and an Azimuth rotation angle of 180 degrees or more on the Earth-directed plane. This data relay satellite further When the direction of the +X axis facing in the positive direction in the right-handed orthogonal coordinates is the satellite traveling direction +X of the data relay satellite and the direction of the +Z axis facing in the positive direction in the right-handed orthogonal coordinates is the geocentric direction +Z of the satellite, it may be equipped with an optical communication device that changes the pointing direction by ±40 degrees around the +X axis with respect to the +Z axis and by ±40 degrees around the +Y axis facing in the positive direction in the right-handed orthogonal coordinates with respect to the +Z axis.

[0059] ***Effects of Embodiment 2**** According to Embodiment 2, since the first data relay satellite 211 and the second data relay satellite 212 are coordinated to transmit monitoring information to the countermeasure devices 310 and 320, information transmission without communication interruption is possible with a small number of communication satellites. Since the communication satellites of the flying object response system 700 can change the communication field of view, information transmission without communication interruption is possible with a small number of communication satellites. Since the flying object response system 700 combines optical communication 71 and radio communication 72 to transmit monitoring information, large-capacity data can be transmitted smoothly. According to Embodiment 2, there is an effect that it becomes possible to take countermeasures against a flying object that intermittently boosts after launch to change the flight direction. In addition, since data can be transmitted to the countermeasure device only by data transmission from the monitoring satellite in space without going through ground facilities, there is an effect that real-time countermeasures can be taken. When the landing point is far away after moving a long distance from the launch point, data is transmitted by long-distance large-capacity optical communication, so there is an effect that countermeasures can be taken at a remote location. Furthermore, by limiting the use of optical communication between data relay satellites, there is an effect that there is no risk of communication interruption.

[0060] <Supplement to Embodiment 2> As described in the background art, an HGV response system has been long awaited. In an HGV, since it intermittently boosts near the boundary between the upper atmosphere and space after launch and flies, it is difficult to estimate the flight path and the landing position, and it is necessary to monitor the flight path until just before landing and transmit it to the countermeasure device almost in real time. In conventional flying objects, since a high-temperature gas called a plume diffuses during boosting, it was possible to detect the temperature of the flying object by infrared rays even at a long distance from the geostationary orbit. However, in the case of an HGV, it is necessary to track the flight path after the boost. In this tracking case, the temperature of the heated aircraft is detected by infrared rays. Since the heated aircraft is not as hot as the plume and the area where the temperature rises is also narrow, there is a problem that it is difficult to detect the HGV from a long distance such as the geostationary orbit.

[0061] As a means of tracking the flight of an HGV, it is effective to use a low Earth orbit (LEO) satellite constellation to monitor it from a short distance. By monitoring the Earth's periphery, it is possible to monitor the flying object against the background of the universe, enabling the tracking of the flying object without being buried in the background signal. In a flying object monitoring system using satellites deployed in high orbits such as geostationary orbits and Molniya orbits for wide-area observation and monitoring on the ground, for example, in the case of a geostationary satellite, the geostationary satellite utilizes the feature of orbiting synchronously with the Earth to constantly monitor a specific area on the ground. However, in order to constantly monitor using a low Earth orbit satellite constellation, the monitoring field of view of an individual satellite is limited, and since it passes over a specific area in a short time, it is necessary to achieve constant monitoring in cooperation with a large number of satellites. In a low Earth orbit satellite constellation, if the number of satellites is sufficiently large, it becomes possible to constantly monitor the entire globe (hereinafter referred to as the world). By equipping with an infrared monitoring device that looks directly down to detect launches and an infrared monitoring device that points to the Earth's periphery to monitor the flying object after boost against the background of the universe, it becomes possible to detect the launch of an HGV and track its flight path after boost.

[0062] However, in order to constantly monitor the world using a huge number of low Earth orbit satellite groups, there are problems such as an increase in the total cost such as satellite maintenance costs and launch costs, and a huge amount of satellite operation and data processing volume.

[0063] As a means of achieving global constant monitoring with a minimal number of satellites, the cooperation of a group of geostationary orbit satellites, a group of polar orbit satellites, and a group of inclined orbit satellites is effective. Among the group of geostationary satellites flying over the equator, although it depends on the orbital altitude, by evenly arranging at least six or more satellites, the equatorial vicinity can be comprehensively monitored by a nadir viewing monitoring device, and the mid-latitude zone can be comprehensively monitored by a limb viewing monitoring device. Since polar orbit satellites pass through the entire circumpolar region, in a group of polar orbit satellites, by evenly arranging at least six or more satellites on one orbital plane, the vicinity of the polar region can be comprehensively monitored by a nadir viewing monitoring device, and the mid-latitude to high-latitude zones can be monitored by a limb viewing monitoring device. In a group of inclined orbit satellites, by optimizing the orbital altitude, orbital inclination angle, and satellite arrangement, the mid-latitude zone can be constantly monitored by a nadir viewing monitoring device with twelve or more satellites, and the equatorial upper air, polar region, and high-latitude upper air can be monitored by a limb viewing monitoring device.

[0064] After obtaining global constant monitoring information with a group of 24 or more monitoring satellites, a means for real-time data transmission to a countermeasure device is required. Therefore, in this application, data is transmitted to the countermeasure device via a data relay satellite flying in a geostationary orbit and a polar orbit with an orbital altitude of 2000 km or more. Satellites flying at an orbital altitude of 2000 km or more and 36000 km or less are generally called medium Earth orbit (MEO) satellites, and a satellite flying at a geostationary orbit altitude of 36000 km is a geostationary (GEO) satellite. With three or more satellites evenly arranged in the longitude direction, it becomes possible to cover the communication range from the equator to the mid-latitude zone with a geostationary satellite. However, ensuring the communication field of view in the polar region becomes an issue.

[0065] Therefore, by cooperating with polar orbit satellites, it becomes possible to ensure a global constant communication line. For mid-latitude satellites, it is necessary to select an orbit that is not affected by the adverse effects of the Van Allen belt. However, there is an operating record of a group of GPS satellites, etc., at least around an orbital altitude of 20000 km, and an operating record of a group of geostationary communication satellites at around an orbital altitude of 8000 km. The higher the orbital altitude, the wider the communication field of view in the atmosphere, so there is an advantage that the entire globe can be covered with a small number of satellites. However, there is a problem in that the latency, which is the waiting time required for communication, is large because of the long distance. In addition, since a large amount of propulsion is required to reach a predetermined altitude after launch, the satellite weight increases, the satellite equipped with a propulsion tank becomes large, and there is a problem in that the number of satellites that can be launched simultaneously is small.

[0066] When the orbital altitude is low, the latency is small, so there is an advantage that the time from detecting the launch of a flying object to transmitting data to a countermeasure device becomes short. Due to this advantage, a small amount of propulsion is required to reach a predetermined altitude after launch, so it is easy to make the satellite smaller and lighter, and the number of satellites that can be launched simultaneously increases, so there is an effect that the total cost can be reduced even if the number of units is large. However, there is a problem in that the number of satellites for covering the entire globe increases.

[0067] In order to ensure a constant communication field of view with low Earth orbit satellites with an orbital altitude of 2000 km or less and countermeasure devices in the airspace, land area, and sea area of the atmosphere, if it is a data relay satellite with an orbital altitude of 8000 km, as shown in FIG. 28, four or more with a communication field of view of ±30 deg in two orthogonal axes with respect to the geocentric direction may cooperate on the same orbital plane. At an orbital altitude of 36000 km, as shown in FIG. 26, three or more with a communication field of view of ±10 deg around two orthogonal axes (+X axis, +Y axis) with respect to the geocentric direction (+Z axis direction) may cooperate on the same orbital plane. In addition, in order for a plurality of monitoring satellites to measure the position of a flying object based on the principle of space triangulation, the number of monitoring satellites capable of real-time data transmission simultaneously by the data relay satellite is two or more. Further, assuming that a plurality of flying objects are launched almost simultaneously, it is reasonable that about six medium-latitude data relay satellites are deployed on the same orbital plane and the communication fields of view with the monitoring satellite group and the countermeasure device overlap. FIG. 29 shows that when six data relay satellites are deployed over the equator at an orbital altitude of 20000 km, the polar regions become incommunicable regions shown as hexagons. Therefore, as shown in FIG. 27, if six data relay satellites are similarly deployed on one orbital plane of a polar orbit, a constant communication line for the entire globe can always be ensured.

[0068] When the flying object flies a long distance, it may be reasonable to transmit data via multiple data relay satellites to a countermeasure device near the area where landing is expected from the location detected by the surveillance satellite. In long-distance communication between data relay satellites, it is reasonable to perform high-capacity communication by optical communication. In optical communication between any two of the first data relay satellites or any two of the second data relay satellites, since they are flying synchronously at the same altitude in the same orbital plane, the relative positional relationship between the satellites does not change with time. Therefore, if optical communication is established by changing the pointing direction in the same orbital plane, then as long as the pointing direction is stabilized thereafter, high-capacity communication can be achieved without interruption.

[0069] On the other hand, in the optical communication between the first data relay satellite and the second data relay satellite, since the equatorial satellite orbits in the longitudinal direction and the polar satellite orbits in the latitudinal direction, various variations occur in the relative positions of any two satellites.

[0070] Therefore, in the present application, as shown in FIGS. 21 to 25, an Elevation field-of-view change range within the same plane enabling inter-satellite optical communication in the same orbital plane is set, and by rotating Azimuth around the geocentric axis, various changes in the line-of-sight direction can be enabled. As the Elevation angle, in the case of a geostationary satellite, excluding the range that becomes the shadow of the earth in the same orbital plane, the maximum range is that the field-of-view direction can be changed by about 80 deg from the satellite's traveling direction towards the earth direction. Communication can be carried out with neighboring satellites on the geostationary orbit at an Elevation angle of about 0 deg, and with distant satellites when in the shadow of the earth at about 80 deg. When the first data relay satellite and the second data relay satellite having this field-of-view change range happen to be arranged in the same orbital plane, communication between any two satellites can be carried out with a similar positional relationship.

[0071] Regarding the elevation angle, when the orbital altitude is 20,000 km, the maximum range is that the viewing direction can be changed by about 72 deg from the satellite moving direction towards the Earth direction, and when the orbital altitude is 8,000 km, the maximum range is that the viewing direction can be changed by about 63 deg from the satellite moving direction towards the Earth direction.

[0072] Next, regarding the communication between two satellites not in the same orbital plane, by rotating the azimuth around the Earth direction (+Z axis) and setting an appropriate elevation angle, optical communication becomes possible in various relative position relationships. Also, even while the relative satellites are moving, by performing appropriate two-axis pointing direction control, optical communication can be continued without communication interruption. In inter-satellite optical communication, since it is necessary to precisely align the optical axes of the optical communication of both satellites, high pointing accuracy and stability are required. Although there is an actual achievement of one-to-one optical communication with the current technology, since there is no example of one satellite continuously performing optical communication with a large number of satellites simultaneously, in a flying object corresponding system assuming multi-satellite simultaneous optical communication, there remains a risk of communication interruption. However, in a flying object corresponding system for security purposes, the impact in the case of communication interruption is extremely large. Therefore, for reliable system formation, it is safe to basically limit the cross-links for simultaneous optical communication to one pair.

[0073] Since the communication between data relay satellites becomes long-distance and high-capacity communication, it is reasonable to adopt optical communication. However, for one data relay satellite to communicate with a large number of monitoring devices simultaneously, it is reasonable to adopt radio communication. In radio communication, by setting the beam spread angle wider, the tolerance of communication interruption due to satellite movement can be improved, and it is also possible for a data relay satellite to operate multiple radio communication devices simultaneously. Also, similar to the positioning satellites such as GPS with actual achievements, it is possible to identify and utilize signals from multiple monitoring satellites transmitted and received from the same antenna. The same applies when transmitting data from one data relay satellite to a large number of countermeasure devices. Even when one satellite communicates with a large number of monitoring satellites and a large number of countermeasure devices simultaneously, real-time communication is possible without communication interruption by radio communication. This is as shown in Fig. 19.

[0074] Regarding the countermeasure devices, in some cases, it may be reasonable to connect a group of countermeasure devices via a dedicated communication link and conduct command and control from a countermeasure device acting as a command center. For example, in the case of the United States, there is a communication line called Link16. For example, there is also an idea of transmitting data from surveillance satellites to Aegis ships in a batch and commanding and controlling the countermeasure actions of multiple assets via Link16. In this case, it is reasonable to adopt optical communication for the communication from the data relay satellite to the countermeasure device. If optical communication is performed with the countermeasure device after receiving the surveillance information from other data relay satellites, even if the optical cross-link between the data relay satellites is interrupted, the countermeasure actions can be carried out. This is as shown in Figure 20.

[0075] Also, when satellite attitude control technology with pointing accuracy and stability for maintaining cross-links in optical communication with multiple targets is established, it becomes possible to use multiple optical communication devices for communication with monitoring satellites or communication with countermeasure devices. Since the sun's incident direction rotates once around the north-south axis while an equatorial satellite orbits the Earth once in the longitudinal direction, it is reasonable to set solar panels with a rotation function around the north-south axis (Y-axis). On the other hand, for a polar orbiting satellite, in addition to the sun's incident direction rotating once in the Elevation direction while the satellite orbits the Earth once in the latitudinal direction, the normal vector of the orbital plane rotates in the Azimuth direction, so there is an issue that the solar panel operating efficiency decreases compared to an equatorial satellite. In the case of a fixed or single-axis rotating solar panel, the solar panel becomes large, and in order to improve the solar panel operating efficiency, it is necessary to have a two-axis rotation function. As a means to solve this problem, by adopting a sun-synchronous orbit and an orbit called a dawn-dusk orbit where the normal vector of the orbital plane always points towards the Earth, it becomes possible to always point the fixed solar panel towards the sun. The sun-synchronous condition has a correlation between the orbital altitude and the orbital inclination angle. The lower the orbit, the closer the orbital inclination angle approaches 90 degrees, so for low Earth orbit (LEO) satellites, it becomes a polar orbit. Up to an orbital altitude of about 5000 km, a sun-synchronous orbit can be achieved only by natural laws, but as the orbital inclination angle deviates from 90 degrees, the constraints for constant polar region monitoring become greater. Although it is also possible to increase the diversity of the orbital altitude and orbital inclination angle for maintaining the sun-synchronous condition by artificially operating the propulsion device, since it requires fuel, determining the optimal conditions will depend on the system design policy. Figure 30 shows the orbital altitude and orbital inclination for maintaining the sun-synchronous condition. The sun 810 is shown in Figure 30. Five sets from (1) to (5) below are shown in Figure 30. (1) Orbital altitude: approximately 5000 km, orbital inclination angle: approximately 139 degrees, latitude: approximately 41 degrees, (2) Orbital altitude: approximately 4000 km, orbital inclination angle: approximately 123 degrees, latitude: approximately 57 degrees (3) Orbital altitude: approximately 3000 km, orbital inclination angle: approximately 112 degrees, latitude: approximately 68 degrees (4) Orbital altitude: approximately 2000 km, orbital inclination angle: approximately 105 degrees, latitude: approximately 75 degrees (5)Orbit altitude is approximately 1000 km, orbit inclination angle is approximately 100 degrees, and latitude is approximately 80 degrees.

[0076] Embodiment 3. Embodiment 3 relates to a system of 24 or more satellites in total, including 6 or more satellites in a polar orbit, 6 or more satellites in an equatorial orbit, and 12 or more satellites in an inclined orbit.

[0077] Embodiment 3 relates to a monitoring system 3000 composed of a plurality of monitoring satellites equipped with a first monitoring device directed towards the Earth's surface and a second monitoring device directed towards the Earth's periphery, and ground facilities. The monitoring system 3000 forms a satellite constellation with a group of polar orbit satellites in which 6 or more monitoring satellites fly in a polar orbit with an orbit inclination angle of 80 degrees or more, a group of inclined orbit satellites in which 12 or more monitoring satellites fly in an inclined orbit with an orbit inclination angle of 10 degrees or more and 80 degrees or less, and a group of equatorial orbit satellites in which 6 or more monitoring satellites fly over the equator with an orbit inclination angle of less than 10 degrees.

[0078] The monitoring system 3000 will be described. The global coverage by the first monitoring device directed towards the geocentric direction will be described. Since the group of polar orbit satellites passes over the polar regions every week, 6 or more satellites in one orbital plane fly by alternately, enabling the first monitoring device to constantly monitor the polar regions. However, coverage cannot be ensured from the mid-latitudes to the low latitudes. In the group of equatorial orbit satellites, 6 or more satellites in one orbital plane fly by alternately, enabling the first monitoring device to constantly monitor the vicinity of the equator. However, monitoring cannot be performed from the mid-latitudes to the high latitudes. In the group of inclined orbit satellites, there is a vast variety due to the combination of orbit altitude, orbit inclination angle, the field of view setting of the first monitoring device, and the number of satellites, but it has been found that the observation coverage of the mid-latitude zone by the first monitoring device can be ensured by 2 or more groups of satellites. However, the polar regions cannot be monitored, and constant monitoring cannot be performed over the equator, and there may be a lack of coverage. The monitoring system 3000 has the effect of ensuring global coverage by the first monitoring device with a small number of satellites by the mutual complementarity of the group of polar orbit satellites, the group of equatorial orbit satellites, and the group of inclined orbit satellites.

[0079] Next, the global coverage by the second monitoring device that points to the periphery of the Earth will be described. Since it is known that the HGV flies at a low altitude of about 100 km or less above the ground surface after launch, the altitude range of the global upper air may be limited to the maximum altitude until the altitude after launch is decreased. The field of view of the second monitoring device by the polar orbiting satellite constellation can cover the high-latitude zones of 60 degrees or more north latitude and 60 degrees or more south latitude when passing near the poles. The field of view of the second monitoring device by the equatorial orbiting satellite constellation spreads over the mid-latitude zones of the Northern Hemisphere and the Southern Hemisphere, and the latitude range to be monitored can be set by selecting the orbital altitude and the orbital inclination angle. With the inclined orbiting satellite constellation, a wide monitoring area can be secured including the polar upper air and the equatorial upper air. By the monitoring system 3000, the polar orbiting satellite constellation, the equatorial orbiting satellite constellation, and the inclined orbiting satellite constellation complement each other, and there is an effect that the global coverage by the second monitoring device can be ensured with a small number of satellites. There is an effect that it is possible to detect the launch of a flying object and track it during flight with at least 24 satellites. There is an effect that the position coordinates of the flying object can be calculated by performing simultaneous monitoring with multiple satellites and performing space triangulation.

[0080] When an infrared sensor is adopted as the first monitoring device and the second monitoring device, the first monitoring device points in the direction of the Earth's center and can detect the high-temperature plume ejected at the time of flying object launch by securing the field of view up to the tangent of the Earth. The second monitoring device points to the periphery of the Earth. If it has a 360-degree field of view around the Azimuth axis with respect to the direction of the Earth's center like a fish-eye camera, the instantaneous field of view becomes ring-shaped, and it becomes possible to cover a wide area as the satellite moves. According to the peripheral Earth monitoring, when the flying object flies over the Earth, it can be monitored against the cosmic background, so it is possible to detect the temperature of the flying object after the end of the ejection, which is not as high as the high-temperature plume. Therefore, it becomes possible to track the flight path after the end of the ejection. In the case of the HGV, it is known that the propulsion device is operated again during flight to change the flight direction, and it becomes possible to detect the ejection during flight and track it after the change by the second monitoring device. Figure 31 conceptually shows the monitoring by the second monitoring device.

[0081] <Explanation of the coverage of the first monitoring device> Figures 32 and 33 show the comprehensiveness of the first monitoring device. For the purpose of comprehensively monitoring the vicinity of the equator on the earth's surface, when six satellites are evenly deployed in an equatorial orbit above the earth, by using the first monitoring device directed towards the center of the earth, if the monitoring range of 60 degrees of longitude per satellite is covered, it becomes possible to constantly monitor the vicinity of the earth's surface equator. If the orbital altitude is 1000 km, it is sufficient to be equipped with the first monitoring device having a field of view range of ±60 degrees in the longitude direction with respect to the direction towards the center of the earth. When a specific monitoring location can be limited within 60 degrees of longitude, it may be equipped with a function for changing the field of view direction with a change range of ±60 degrees in the line-of-sight direction. Also, when it is necessary to constantly monitor the entire 60 degrees of longitude, a plurality of monitoring devices may be mounted on one satellite, or the number of satellites in the same orbital plane may be increased according to the field of view range of the monitoring device without limiting the number of satellites to six. In order to comprehensively cover and constantly monitor the vicinity of the earth's surface equator, an overlap of the monitoring areas with satellites flying before and after in the same orbit is also required, so the system construction becomes easier if eight or more satellites are deployed. Also, if the orbital altitude is increased, a feasible solution with a narrowed field of view range of the monitoring device can also be found.

[0082] Figure 34 shows a schematic diagram of the monitoring range of a polar orbiting satellite. Based on the same concept, in a polar orbit with an orbital inclination angle of 80 degrees or more, if six or more satellites are evenly distributed and flown in the same orbital plane, and from an orbital altitude of 1000 km, the first monitoring device ensures a field of view range of ±60 degrees from the direction towards the center of the earth to the direction of travel, it becomes possible to constantly monitor the circumference on the earth's surface on the relevant orbital plane. Since all polar orbiting satellites pass through the polar regions in all orbits, if there is one orbital plane with six evenly deployed satellites, constant monitoring of the polar regions can be realized due to the movement of the orbital plane relative to the earth with the rotation of the earth.

[0083] Figure 35 shows a schematic diagram of the monitoring range of a polar orbiting satellite. A satellite constellation capable of comprehensively monitoring the mid-latitude zone is known, which consists of twelve or more satellites flying at an altitude of about 2000 km in an inclined orbit set at an orbital inclination angle of about 45 degrees. If the number of satellites increases, it is possible to comprehensively monitor the mid-latitude zone even at an orbital altitude of 1000 km.

[0084] Figure 36 shows the comprehensiveness of the first monitoring device. The geostationary satellite constellation, the polar-orbiting satellite constellation, and the inclined-orbit satellite constellation cannot individually cover the entire globe. However, by combining the three satellite constellations, it is possible to achieve comprehensive and continuous global monitoring by the first monitoring device. In addition, since the entire globe can be covered with a minimum of 24 satellites, there is an effect of reducing the system setup cost. As a result, it is possible to detect the launch of a flying object using the first infrared sensor. Also, by detecting the temperature during the flight phase after the ejection of the flying object using the second infrared sensor, flight tracking becomes possible. In addition, in areas where multiple satellites can simultaneously monitor, it is possible to derive the position coordinates of the flying object based on the principle of space triangulation.

[0085] <Explanation of the comprehensiveness of the second monitoring device> Figures 37 and 38 are diagrams for explaining the comprehensiveness of the second monitoring device. Next, the comprehensiveness of the field of view of the second monitoring device directed towards the Earth's periphery is shown. For geostationary satellites, the mid-latitude zones in the Northern Hemisphere and the mid-latitude zones in the Southern Hemisphere are the field of view, and by orbiting the equator, the mid-latitude zones are covered as a ring-shaped monitoring area.

[0086] Figures 39 and 40 show polar-orbiting satellites. In polar-orbiting satellites, when passing near the North Pole, the area around 60°N latitude is the field of view, and when passing near the South Pole, the area around 60°S latitude is the field of view. By flying in the north-south direction, a ring-shaped field of view is formed when viewed from the equator. Even if the orbital plane is a single plane, due to the effect of the Earth's rotation, the monitoring area moves over time. If the second monitoring device has a 360° field of view around the Azimuth axis with respect to the geocentric direction like a fish-eye camera, one satellite can cover the area from the North Pole to around 60°N latitude in a ring shape. Since polar-orbiting satellites pass through the polar regions every orbit, even if the orbital plane is single, by having 6 or more satellites flying alternately, the areas around 60°N latitude and 60°S latitude are constantly covered. Also, the high-latitude zones of 60° or more are constantly covered by the forward view and the rear view before and after passing through the polar regions.

[0087] Figures 41 and 42 show the field of view of the second monitoring device on an inclined orbit satellite. The field of view of the second monitoring device on an inclined orbit satellite forms a ring in a diagonal shape, including the polar regions and the vicinity of the equator. Furthermore, since the inclined orbit satellite constellation is evenly formed in the longitudinal direction, the field of view range formed by the inclined orbit satellite constellation almost covers the entire globe.

[0088] Figure 43 shows the global coverage by the second monitoring device. In Figure 43, only the satellite with an angle attached to the second monitoring device shows the monitoring field of view. Actually, as shown in Figure 37, the area where the monitoring field of view can monitor the Earth's surface forms a band on the Earth's surface. By combining the field of view ranges of the second monitoring devices of the equatorial orbit satellite constellation, the polar orbit satellite constellation, and the inclined orbit satellite constellation, global coverage is ensured. Furthermore, since the fields of view of multiple satellites overlap simultaneously, stereoscopic vision by space triangulation becomes possible, and it becomes possible to calculate the flight position coordinates.

[0089] In the monitoring system 3000 of Embodiment 3, it is as follows. The monitoring system 3000 includes a plurality of monitoring satellites equipped with a first monitoring device directed at the Earth's surface and a second monitoring device directed at the Earth's periphery, and ground facilities. Six or more monitoring satellites form a satellite constellation as an equatorial orbit satellite constellation flying over the equator with an orbital inclination angle of less than 10 degrees. In this monitoring system 3000, the orbit is an elliptical orbit, and the monitoring range of the second monitoring device is expanded to the high-latitude side near the apogee and to the low-latitude side near the perigee. Figures 44 and 45 show the relationship between the orbital latitude and the Earth's tangent. According to this monitoring system 3000, The tangent direction at a latitude of 20°N with an orbital altitude of about 400 km, The tangent direction at a latitude of 30°N with an orbital altitude of about 1000 km, The tangent direction at a latitude of 40°N with an orbital altitude of about 2000 km, The tangent direction at a latitude of 50°N with an orbital altitude of about 3600 km, The tangent direction at a latitude of 60°N with an orbital altitude of about 12800 km, Can each be monitored against the cosmic background. Therefore, if an elliptical orbit is adopted over the equator and the monitoring is set such that the upper limit of the high latitude is at the apogee and the lower limit of the low latitude is at the perigee, the desired monitoring range can be covered. When numbering the satellite constellation over the equator in sequence, if the orbital planes are set alternately such that the odd-numbered satellites are at the apogee and the even-numbered satellites are at the perigee, the observation range can be reasonably expanded. Since the major axis of the elliptical orbit rotates within the orbital plane, in order to monitor a specific monitoring area at a specific local solar time (LST), the major axis can be arranged at an appropriate position at the LST and the orbit can be frozen to maintain the monitoring range. Although it is difficult to realize the frozen orbit only by natural phenomena due to large constraints on the orbital parameters, by operating the propulsion system, a highly flexible parameter setting becomes possible.

[0090] In addition, in the monitoring system 3000 of Embodiment 3, the orbit may be a frozen orbit.

[0091] In addition, the monitoring system 3000 of Embodiment 3 may have the following configuration. The monitoring system 3000 includes a plurality of monitoring satellites equipped with a first monitoring device directed at the Earth's surface and a second monitoring device directed at the Earth's periphery, and ground facilities. In the monitoring system 3000, six or more monitoring satellites form a satellite constellation as a group of satellites flying over the equator with an orbital inclination angle of less than 10 degrees. In the monitoring system 3000, the orbit is an elliptical orbit, and the monitoring range of the second monitoring device is expanded to the high-latitude side of the Northern Hemisphere and the low-latitude side of the Southern Hemisphere at the northernmost point of the orbit, and to the high-latitude side of the Southern Hemisphere and the low-latitude side of the Northern Hemisphere at the southernmost point of the orbit.

[0092] In addition, in the monitoring system 3000, the normal vector of the orbital plane may be synchronized with the Earth's rotation.

[0093] All the satellites appearing in Embodiment 1 to Embodiment 3 are controlled by a control device or a control system located on the Earth.

[0094] The above has described Embodiment 1 to Embodiment 3. Among these embodiments, two or more of them may be combined and implemented. Alternatively, one of these embodiments may be partially implemented. Alternatively, two or more of these embodiments may be partially combined and implemented.

Description of Reference Numerals

[0095] 100, 101, 102, 103 Monitoring satellites, 110 First monitoring device, 120 Second monitoring device, 11S +X+Y sensor, 12S +X-Y sensor, 13S -X+Y sensor, 14S -X-Y sensor, 15S Directly below monitoring sensor, 21S +Y sensor, 22S -Y sensor, 31S +X sensor, 32S +Y sensor, 33S -Y sensor, 34S Directly below monitoring sensor, 41C Communication device, 51C, 52C, 53C, 54C, 55C, 56C Communication devices, 71 Optical communication, 72 Radio wave communication, 201, 202 Communication satellites, 211 First data relay satellite, 212 Second data relay satellite, 213 Second data relay satellite, 220C Optical communication device, 230C Communication device, 300 Ground equipment, 310, 320 Countermeasure devices, 330 Communication line, 333 Flying object, 400 Earth, 501, 502, 503 Monitoring systems, 600 Satellite information transmission system, 700 Flying object response system, 3000 Monitoring system.

Claims

【Claim 1】 When the +X axis direction facing in the positive direction in the right-handed orthogonal coordinates is set as the satellite's satellite traveling direction +X, and the +Z axis direction facing in the positive direction in the right-handed orthogonal coordinates is set as the satellite's geocentric direction +Z, an optical communication device that changes the pointing direction by ±40 degrees around the +X axis with respect to the +Z axis and by ±40 degrees around the +Y axis facing in the positive direction in the right-handed orthogonal coordinates with respect to the +Z axis, and transmits the monitoring information acquired by the monitoring satellite group to the countermeasure device in real time via data transmission A data relay satellite comprising the same.

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