Aerial vehicle response systems and data relay satellites

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, an airborne object handling system for handling airborne objects, and a data relay device. [Background technology]

[0002] Conventionally, there are monitoring systems that use satellite constellations (for example, Patent Document 1). An inclined orbit constellation has the advantage of being able to build a system that can constantly monitor the mid-latitudes with a small number of satellites. With monitoring satellites that point toward the edge of the Earth and track the temperature of a flying object after it has been launched, if there is a monitoring device that monitors the edge of the Earth in a ring shape all around the circumference in the direction of the geocenter, it will be possible to monitor the entire globe with a small number of satellites.

[0003] For a new flying object called a Hyperpersonic Guided Vehicle (HGV), infrared detection of the heated vehicle is an effective means for tracking after the end of the thrust at launch. In this case, monitoring the Earth's edge with space as the background is effective to prevent background signals from becoming noise. In principle, a fisheye camera can monitor the entire circumference in a ring shape, but fisheye cameras have limitations in terms of spatial resolution and monitoring performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 175696 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure aims to provide a monitoring system that is capable of continuous global monitoring with a small number of satellites and has high spatial resolution and monitoring performance. [Means for solving the problem]

[0006] The data relay satellite according to the present disclosure comprises: The direction of the +X axis, which faces the positive direction in the right-handed Cartesian coordinate system, is the satellite's direction of travel +X. If the +Z axis, which points in the positive direction in the right-handed Cartesian coordinate system, is the direction of the satellite's geocenter, then An optical communication device that changes the pointing direction by ±40 degrees around the +X axis relative to the +Z axis, and by ±40 degrees around the +Y axis, which faces in the positive direction in right-hand Cartesian coordinates, relative to the +Z axis, and transmits monitoring information acquired by a group of monitoring satellites to a countermeasure device in real time. Equipped with. [Effects of the Invention]

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

[0008] [Figure 1] 1 is a diagram of the first embodiment, showing three views of a monitoring satellite 101 provided in a monitoring system 501. FIG. [Figure 2] FIG. 1 is a diagram of the first embodiment, showing a monitoring satellite 101 viewed on the YZ plane. [Figure 3] FIG. 1 is a diagram of the first embodiment, showing the monitoring field of view when a monitoring satellite 101 flies northward above the equator. [Figure 4] FIG. 1 is a diagram of the first embodiment, showing the monitoring field of view when a monitoring satellite 101 flies southward above the equator. [Figure 5] FIG. 1 is a diagram of the first embodiment, showing a state in which a monitoring satellite 101 is positioned above the equator and at the northernmost point of the orbital plane. [Figure 6] FIG. 1 is a diagram of the first embodiment, showing a state in which a plurality of monitoring satellites 101 fly in each of two inclined orbits. [Figure 7] FIG. 1 is a diagram of the first embodiment, showing the relationship between the orbital altitude and latitude of the monitoring field of view directed toward the edge of the Earth. [Figure 8] FIG. 1 is a diagram of the first embodiment, showing four views of a monitoring satellite 102 provided in a monitoring system 502. [Figure 9] FIG. 1 is a diagram of the first embodiment, showing four views of a monitoring satellite 103 provided in a monitoring system 503. [Figure 10] FIG. 1 is a diagram of the first embodiment, showing a monitoring satellite 101 equipped with a communication device 41C. [Figure 11] FIG. 1 is a diagram of the first embodiment, showing a monitoring satellite 102 equipped with a communication device 41C. [Figure 12] FIG. 1 is a diagram of the first embodiment, showing a monitoring satellite 103 equipped with a communication device 41C. [Figure 13] FIG. 1 is a diagram of the first embodiment, showing four views of a communication satellite 201 provided in a satellite information transmission system 600. [Figure 14] FIG. 1 is a diagram of the first embodiment, showing four views of a communication satellite 202 provided in a satellite information transmission system 600. [Figure 15] FIG. 6 is a diagram of the first embodiment, showing that a satellite information transmission system 600 transmits satellite information of a monitoring system 501. [Figure 16] FIG. 6 is a diagram of the first embodiment, showing that a satellite information transmission system 600 transmits satellite information of a monitoring system 502. [Figure 17] FIG. 6 is a diagram of the first embodiment, showing that the satellite information transmission system 600 transmits satellite information of the monitoring system 503. [Figure 18] FIG. 7 is a diagram of a second embodiment, showing a flying object response system 700. [Figure 19] FIG. 10 is a diagram of the second embodiment, showing the state of radio wave communication 72. [Figure 20] FIG. 7 is a diagram of the second embodiment, showing transmission using optical communication 71, radio wave communication 72, and communication line 330. [Figure 21] FIG. 10 is a diagram of the second embodiment, showing the range of change of the communication field of view of the azimuth and elevation of the optical communication device 220C provided on the data relay satellites 211 and 212. [Figure 22] FIG. 10 is a diagram of the second embodiment, illustrating the effect of being able to change the communication field of view of the optical communication device 220C between the first data relay satellite 211 and the second data relay satellite 212. [Figure 23]FIG. 10 is a diagram of the second embodiment, showing a change in the communication field of view of the optical communication device 220C from the first data relay satellite 211 to the second data relay satellite 212. [Figure 24] FIG. 10 is a diagram of the second embodiment, showing that the communication field of view direction can be changed by 360 degrees in azimuth and between 0 and 70 degrees in elevation. [Figure 25] FIG. 10 is a diagram of the second embodiment, showing that the communication field of view direction can be changed by 360 degrees in azimuth and between 0 and 60 degrees in elevation. [Figure 26] FIG. 10 is a diagram of the second embodiment, and relates to a communication device 230C provided on the first data relay satellite 211 and the second data relay satellite 212. [Figure 27] FIG. 10 is a diagram of the second embodiment, showing that the communication field of view can be changed by ±20 degrees around the +X axis relative to the +Z axis, and by ±20 degrees around the +Y axis relative to the +Z axis. [Figure 28] FIG. 10 is a diagram of the second embodiment, showing that the communication field of view can be changed by ±30 degrees around the +X axis relative to the +Z axis, and by ±30 degrees around the +Y axis relative to the +Z axis. [Figure 29] FIG. 10 is a diagram of the second embodiment, showing that when six data relay satellites are deployed, the polar regions become communication dead zones, indicated by hexagons. [Figure 30] FIG. 10 is a diagram of the second embodiment, showing the orbital altitude and orbital inclination that maintain the sun-synchronous condition. [Figure 31] FIG. 10 is a diagram of the third embodiment, conceptually showing monitoring by a second monitoring device. [Figure 32] FIG. 10 is a diagram of the third embodiment, showing the coverage of the first monitoring device. [Figure 33] FIG. 10 is another diagram showing the coverage of the first monitoring device according to the third embodiment. [Figure 34] FIG. 10 is a diagram of the third embodiment, showing a schematic diagram of the monitoring range of a polar orbiting satellite. [Figure 35] FIG. 10 is a diagram of the third embodiment, showing a schematic diagram of the monitoring range of a polar orbiting satellite. [Figure 36] FIG. 10 is a diagram of the third embodiment, showing the coverage of the first monitoring device. [Figure 37]FIG. 10 is a diagram of the third embodiment, illustrating the coverage of the second monitoring device. [Figure 38] FIG. 11 is another diagram illustrating the coverage of the second monitoring device according to the third embodiment. [Figure 39] FIG. 10 is a diagram of a third embodiment, showing a polar orbiting satellite. [Figure 40] FIG. 10 is another diagram showing a polar orbiting satellite according to the third embodiment. [Figure 41] FIG. 10 is a diagram of the third embodiment, showing the field of view of a second monitoring device on an inclined orbit satellite. [Figure 42] FIG. 10 is another diagram of the third embodiment showing the field of view of the second monitoring device on the inclined orbit satellite. [Figure 43] FIG. 10 is a diagram of the third embodiment, showing the global coverage provided by the second monitoring device. [Figure 44] FIG. 10 is a diagram of the third embodiment, showing the relationship between orbital latitude and the earth tangent. [Figure 45] FIG. 10 is another diagram showing the relationship between orbital latitude and the earth tangent in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals. In the description of the embodiments, the description of identical or corresponding parts will be omitted or simplified as appropriate.

[0010] Embodiment 1 ***Configuration Description***

[0011] In the following embodiment, the satellite flight direction and the geocentric direction are defined as follows. The direction of the +X axis, which faces the positive direction in the right-handed Cartesian coordinate system, is the satellite's direction of travel +X. The direction of the +Z axis, which points in the positive direction in the right-handed Cartesian coordinate system, is defined as the geocentric direction of the satellite.

[0012] In the following embodiments, the term "sensor" refers to an infrared sensor.

[0013] <Monitoring System 501: Inclined Orbit> The monitoring system 501 will be described with reference to FIGS. In the monitoring system 501, the monitoring satellite 101 flies in an inclined orbit. FIG. 1 is a three-view diagram of a monitoring satellite 101 provided in a monitoring system 501. FIG. FIG. 2 is a diagram of the monitoring satellite 101 as viewed on the YZ plane. FIG. 3 shows the monitoring field of view of the monitoring satellite 101 when it flies northward above the equator. FIG. 4 shows the field of view monitored by the monitoring satellite 101 when it flies southward above the equator. FIG. 5 shows the monitoring satellite 101 positioned above the equator and at the northernmost point of the orbital plane. FIG. 6 shows a state in which a plurality of monitoring satellites 101 fly in each of two inclined orbits. Figure 7 shows the relationship between orbital altitude and latitude for surveillance views directed toward the Earth's periphery.

[0014] As shown in Fig. 6, monitoring system 501 includes multiple monitoring satellites 101 and ground equipment 300. Ground equipment 300, described below, receives monitoring information acquired by the monitoring satellites from the monitoring satellites via a relay satellite. As shown in Fig. 1, monitoring satellite 101 includes a first monitoring device 110 pointing toward the Earth's surface and a second monitoring device 120 pointing toward the Earth's periphery. In monitoring system 501, a satellite constellation is formed by a group of inclined orbit satellites, each of which has an inclination angle of 10 degrees or more and 80 degrees or less, and 12 or more monitoring satellites 101. As shown in Figure 1, In the monitoring system 501, the second monitoring device 120 If the direction of the +X axis pointing in the positive direction in the right-handed Cartesian coordinate system is the satellite flight direction +X of the monitoring satellite 101, and the direction of the +Z axis pointing in the positive direction in the right-handed Cartesian coordinate system is the geocentric direction +Z of the monitoring satellite 101, then Around the +Z axis relative to the +X axis, +45 degree +X+Y sensor 11S, +XY sensor 12S pointing at -45 degrees, -X+Y sensor 13S pointing at +135 degrees, -XY sensor 14S, which points at -135 degrees, It has. The second monitoring device 120 When flying northeastward, +XY sensor 12S monitors the high latitudes of the Northern Hemisphere, -X+Y sensor 13S monitors the high latitudes of the Southern Hemisphere, When flying southeastward, -XY sensor 14S monitors the high latitudes of the Northern Hemisphere, +X+Y sensor 11S monitors the high latitudes of the Southern Hemisphere.

[0015] This will be explained in detail below. The advantage of an inclined orbit constellation is that it allows the construction of a system capable of constantly monitoring the mid-latitudes with a small number of satellites. For monitoring satellites that are aimed at the edge of the Earth and track the temperature of a projectile after it is launched, if there is a monitoring device that monitors the edge of the Earth in a ring shape around the entire circumference in the direction of the geocenter, it will be possible to monitor the entire globe with a small number of satellites. For a new flying object known as a hyperpersonic guided vehicle (HGV), infrared detection of the heated vehicle is an effective means for tracking after the end of the launch thrust. To prevent background signals from becoming noise when monitoring an HGV, monitoring the Earth's periphery against the background of space is effective, and the second monitoring device 120 is a reasonable monitoring method. In principle, a fisheye camera can monitor the entire circumference of the Earth in a ring shape. However, fisheye cameras have limitations in terms of spatial resolution and monitoring performance. Therefore, if multiple wide fields of view are used to ensure a monitoring field of view all around the earth's center, the feasibility of achieving high spatial resolution and monitoring performance will increase. However, on the other hand, an inclined orbit is characterized by the fact that the field of view of the monitoring equipment varies greatly when flying over the equator and at the northernmost or southernmost end of the orbital plane. Also, from the perspective of efficient use of satellite-generated power, it is rational to appropriately manage the overlapping areas of the field of view of the satellites that make up the satellite constellation.

[0016] Therefore, in the monitoring system 501 of the first embodiment, the second monitoring device 120 that monitors the Earth's periphery is Around the +Z axis in the direction of the earth's center relative to the satellite's direction of travel +X +45 degree +X+Y sensor 11S, +XY sensor 12S pointing at -45 degrees, -X+Y sensor 13S pointing at +135 degrees, -XY sensor 14S, which points at -135 degrees, There are a total of four sets. The second monitoring device 120 When flying northeast +XY sensor 12S monitors the high latitudes of the Northern Hemisphere, -X+Y sensor 13S monitors the high latitudes of the Southern Hemisphere, When flying southeast -XY sensor 14S monitors the high latitudes of the Northern Hemisphere, +X+Y sensor 11S monitors the high latitudes of the Southern Hemisphere.

[0017] In Figure 1, the dashed line indicates +X+Y sensor 11S monitoring field 11, +XY sensor 12S monitoring field 12, The monitoring field of view 13 of the -X+Y sensor 13S and the monitoring field of view 14 of the -XY sensor 14S are shown.

[0018] The first monitoring device 110 has a direct-nadir monitoring sensor 15S having a direct-nadir monitoring field of view 15 in the earth's center direction +Z. The monitoring field of view 15 of the direct-nadir monitoring sensor 15S is indicated by a broken line.

[0019] To monitor the skies above high latitudes or the equator against a cosmic background, a satellite constellation consisting of inclined orbit satellites is advantageous because the monitoring ranges of polar orbit satellites and equatorial satellites are limited. Also, for satellites flying in formation in the same orbital plane, there is a large overlap between the forward and backward fields of view. Therefore, in the monitoring system 501, the monitoring fields of the four second monitoring devices 120 are tilted by approximately 45 degrees from the satellite flight direction +X, as shown in the XY coordinate system in Figure 1. This makes it possible to rationally monitor high latitude skies such as the polar regions and the equatorial skies, while also saving satellite resources in latitude bands where there is a lot of overlap. In an inclined orbit, a satellite flying northeast above the equator will fly east at the northernmost point of the orbital plane, then change direction to southeast. Similarly, a satellite flying southeast above the equator will fly east at the southernmost point of the orbital plane, then change direction to northeast. This causes the field of view of the four second monitoring devices 120 to fluctuate significantly with respect to the north, south, east, and west directions. As shown in Figure 3, when the monitoring satellite 101 passes over the equator in a northeasterly direction, the +XY sensor 12S pointing at -45 degrees monitors the skies from mid-latitude to high-latitude in the Northern Hemisphere. As shown in Fig. 4, when the monitoring satellite 101 passes over the equator in a southeasterly direction, the -XY sensor 14S pointing at -135 degrees monitors the skies above mid- to high latitudes in the Northern Hemisphere. Similarly, as shown in Fig. 3, when the monitoring satellite 101 passes over the equator in a northeasterly direction, the -X+Y sensor 13S pointing at +135 degrees monitors the skies above mid- to high latitudes in the Southern Hemisphere, and as shown in Fig. 4, when the monitoring satellite 101 passes over the equator in a southeasterly direction, the +X+Y sensor 11S pointing at +45 degrees monitors the skies above mid- to high latitudes in the Southern Hemisphere.

[0020] 3 and 4, if the purpose of monitoring is limited to the Northern Hemisphere, it is possible to mount only the +XY sensor 12S pointing at -45 degrees and the -XY sensor 14S pointing at -135 degrees. Furthermore, by simultaneously monitoring a flying object from multiple monitoring satellites, it is possible to measure its orbital position using the principle of spatial triangulation. The more monitoring satellites that are simultaneously monitoring, the more accurate the measurement. Therefore, by simultaneously operating four second monitoring devices 120 on each monitoring satellite 101, it is possible to monitor a wide area with high measurement accuracy. Furthermore, if the monitoring area is limited, it is possible to operate only sensors with high monitoring effectiveness, thereby saving satellite resources such as electricity.

[0021] <Peripheral Surveillance> This will be explained with reference to Figure 7. When monitoring the Earth's periphery from an orbital altitude of 1,000 km, if the line-of-sight vector is tilted 30 degrees in the elevation direction relative to the north direction of the north-south axis, the satellite will be pointed tangentially toward a latitude near 30 degrees north. When monitoring the Earth's periphery from an orbital altitude of 2,000 km, if the line-of-sight vector is tilted 40 degrees in the elevation direction relative to the north direction of the north-south axis, the satellite will be pointed tangentially toward a latitude near 40 degrees north. Therefore, if the line-of-sight vector of the second monitoring device 120 has a field of view ranging from 20 degrees to 40 degrees in elevation relative to the XY plane, the Earth's periphery can be monitored from a monitoring satellite at an orbital altitude of 1,000 km to 2,000 km. The 20 degrees and 40 degrees shown in the XZ plane in Figure 1 indicate this field of view.

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

[0023] The monitoring system 502 includes a plurality of monitoring satellites 102, each having a first monitoring device 110 pointing toward the Earth's surface and a second monitoring device 120 pointing toward the Earth's periphery, and a ground facility 300. Six or more monitoring satellites 102 form a satellite constellation by flying in equatorial orbits above the equator with an inclination angle of 10 degrees or less. Similar to FIG. 6, the monitoring system 502 includes a ground facility 300. As shown in FIG. 8, in the monitoring system 502, The second monitoring device 120 The direction of the +X axis, which faces the positive direction in the right-handed Cartesian coordinate system, is the satellite flight direction +X of the monitoring satellite 102. If the direction of the +Z axis pointing in the positive direction in the right-handed Cartesian coordinate system is the geocentric direction +Z of the monitoring satellite 102, then: Around the +Z axis relative to the +X axis, +Y sensor 21S, which points at +90 degrees, -Y sensor 22S, which points at -90 degrees, It has. The second monitoring device +Y sensor 21S monitors the mid-latitudes of the Southern Hemisphere, -Y sensor 22S monitors the mid-latitudes of the Northern Hemisphere.

[0024] In FIG. 8, the monitoring field 21 of the +Y sensor 21S and the monitoring field 22 of the −Y sensor 22S are indicated by dashed lines.

[0025] The first monitoring device 110 has a direct-nadir monitoring sensor 23S having a direct-nadir monitoring field of view 23 in the earth's center direction +Z. The monitoring field of view 23 of the direct-nadir monitoring sensor 23S is indicated by a broken line.

[0026] Needless to say, if the purpose of monitoring is only the northern and southern hemispheres or only the northern hemisphere, it is possible to mount only one of the +Y sensor 21S pointing at +90 degrees and the -Y sensor 22S pointing at -90 degrees.

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

[0028] The monitoring system 503 includes a plurality of monitoring satellites 103, each having a first monitoring device 110 pointing toward the Earth's surface and a second monitoring device 120 pointing toward the Earth's periphery, a ground facility 300, and Six or more monitoring satellites 103 fly in polar orbits with an inclination angle of 80 degrees or more, forming a satellite constellation. The monitoring system 503 includes the ground facility 300, as in FIG. 6. The monitoring satellites 103 fly in sun-synchronous Dawndusk orbits. The second monitoring device 120 The direction of the +X axis, which faces the positive direction in the right-handed Cartesian coordinate system, is the satellite direction of the monitoring satellite 103, +X. When the direction of the +Z axis pointing in the positive direction in a right-handed Cartesian coordinate system is the geocentric direction of the monitoring satellite, +Z, a +X sensor 31S pointing in the direction of the +X axis; Around the +Z axis relative to the +X axis, +Y sensor 32S, which points at +90 degrees, -Y sensor 33S, which points to -90 degrees, It has. The second monitoring device 120 +X sensor 31S monitors the +X axis direction, +Y sensor 32S monitors the eastern sky above the Earth, -Y sensor 33S monitors the western sky above the Earth.

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

[0030] The first monitoring device 110 has a nadir monitoring sensor 34S with a nadir monitoring field of view 34 in the geocentric direction +Z. The monitoring field of view 34 of the nadir monitoring sensor 34S is indicated by a dashed line. 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, the monitoring satellite 103 passes through the polar regions every time it orbits, so the monitoring system 503 can ensure comprehensive monitoring of high latitude areas even in the orbital plane. The monitoring satellite, which generates power using solar cells, flies in a polar orbit called Dawndusk, which allows the monitoring system 503 to fly with its fixed solar array paddle always pointed toward the sun.

[0032] <Communication Device 41C> The monitoring satellite 101, the monitoring satellite 102, and the monitoring satellite 103 are each equipped with a communication device 41C. FIG. 10 shows a monitoring satellite 101 equipped with a communication device 41C. FIG. 11 shows a monitoring satellite 102 equipped with a communication device 41C. Fig. 12 shows a monitoring satellite 103 equipped with a communication device 41C. Figs. 10 to 12 show the communication field of view 41 of the communication device 41C. Hereinafter, when there is no need to distinguish between the monitoring satellites 101, 102, and 103, they will be referred to as monitoring satellite 100.

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

[0034] A satellite constellation formed by a plurality of monitoring satellites 100 provided in monitoring system 501, monitoring system 502 or monitoring system 503 is formed at an orbital altitude of 1000 km or higher. The monitoring satellites 100 forming the satellite constellation transmit the acquired monitoring information to the ground facility 300 via a satellite information transmission system, which is a transmission system formed at an orbital altitude of 800 km or less and which relays and transmits satellite information between the monitoring satellites 100 and the ground facility 300. The satellite information transmission system will be described later. Satellite constellations have the advantage that the lower the altitude, the less transmission delay there is. There are known plans to form a satellite information transmission system at an orbital altitude of 300 to 700 km. Even if the orbital altitude of a monitoring system with a communication field of view on the Earth-pointing side of the monitoring satellite is around 1000 km, monitoring information can be transmitted via a satellite information transmission system at an orbital altitude of 800 km or less.

[0035] Or it could be something like this: A satellite constellation formed by a plurality of monitoring satellites 100 provided in monitoring system 501, monitoring system 502 or monitoring system 503 is formed at an orbital altitude of 1200 km or higher. The monitoring satellites 100 that form the satellite constellation transmit the acquired monitoring information to the ground equipment 300 via a satellite information transmission system, which is a transmission system formed at an orbital altitude of 1000 km or less and which relays and transmits satellite information between the monitoring satellites 100 and the ground equipment 300. Satellite constellations have the advantage that the higher the altitude, the fewer satellites needed to ensure a wide field of view. On the other hand, there is a known concept of forming a satellite information transmission system at an orbital altitude of around 1,000 km, and if the orbital altitude of a monitoring system with a communication field of view on the Earth-pointing side of the monitoring satellite is 1,200 km or higher, monitoring information can be transmitted via the satellite information transmission system at an orbital altitude of around 1,000 km.

[0036] <Satellite Information Transmission System 600> A satellite information transmission system 600 will be described with reference to FIGS. FIG. 13 is a four-view diagram of the communication satellite 201 provided in the satellite information transmission system 600. The communications satellite 201 is equipped with a communications device 55C that communicates with a surveillance satellite in the direction opposite to the Earth. In the two XY coordinate diagrams in Figure 13, the communications devices on the back side that are not actually visible are indicated by white circles, and the communications devices that are actually present are indicated by black circles. In Figure 13, two communications devices are located on the Earth side, and three communications devices are located on the opposite side to the Earth. FIG. 14 is a four-view diagram of the communication satellite 202 provided in the satellite information transmission system 600. The meanings of the black and white circles in Fig. 14 are the same as in Fig. 13. In Fig. 14, communication device 56C that communicates with ground equipment 300 is placed on the surface facing the earth. FIG. 15 shows that a satellite information transmission system 600 transmits satellite information of a monitoring system 501 . FIG. 16 shows that a satellite information transmission system 600 transmits satellite information for a monitoring system 502 . FIG. 17 shows that a satellite information transmission system 600 transmits satellite information of a monitoring system 503 .

[0037] The communication satellite 201 will be described with reference to FIG. 13. In the satellite information transmission system 600, eight or more communication satellites, each having an inter-satellite communication device for communicating among themselves and an inter-terrestrial communication device for communicating with the ground facility 300, fly in the same orbital plane. More specifically, eight or more communication satellites, each having an inter-satellite communication device and an inter-terrestrial communication device, fly in the same orbital plane in a substantially uniform arrangement. The eight or more orbital planes are arranged in the longitude direction, so that the multiple communication satellites form a satellite constellation. More specifically, the eight or more orbital planes are arranged substantially evenly in the longitude direction. "Approximately evenly arranged in the longitude direction" means that eight or more orbital planes are obtained by rotating one orbital plane around a rotation axis corresponding to a virtual N-S axis connecting the North Pole and the South Pole, and these orbital planes are arranged at substantially equal intervals. The eight or more orbital planes are inclined orbits. One or more communications satellites, which are communications satellites 201, The direction of the +X axis, which faces the positive direction in the right-handed Cartesian coordinate system, is the satellite flight direction +X of the communication satellite 201. If the direction of the +Z axis pointing in the positive direction in the right-handed Cartesian coordinate system is the geocentric direction of the communication satellite 201, then: As it passes north over the equator, a first optical communication device 51C that performs optical communication with a satellite ahead in the flight direction on the same orbital plane; a second optical communication device 52C that performs optical communication with a satellite located behind in the flight direction on the same orbital plane; a third optical communication device 53C that optically communicates with a satellite flying northeast (+X+Y) in an adjacent orbit on the east side (+Y direction) of the +Y axis that faces the positive direction in a right-handed Cartesian coordinate system; a fourth optical communication device 54C that optically communicates with a satellite flying in the southwest (-XY) of an adjacent orbit to the west (-Y); a communication device 55C which is an inter-monitoring communication device that communicates with the monitoring satellite 100 while pointing in the direction opposite to the +Z axis (-Z); It has. The Azimuth communication field of view of the third optical communication device 53C is ±90 degrees or more with respect to the +X axis direction. The Azimuth communication field of view of the fourth optical communication device 54C is ±90 degrees or more in the direction opposite 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 in the direction opposite the +Z axis. Figure 13 shows the communication field of view of each communication device. The code for the communication field of view is the number obtained by removing the letter C from the code for the communication device.

[0038] <Communications Satellite 202> The satellite information transmission system 600 also includes a communication satellite 202 shown in FIG. Communication satellite 202 differs from communication satellite 201 in that communication device 56C is arranged on the Earth-facing side. Communication device 56C in FIG. 14 is oriented in the direction of the +X axis and communicates with ground equipment 300. FIG. 14 also shows the communication field of view of each communication device. The code for the communication field of view is a number obtained by removing the letter C from the code for the communication device. The communication field of view 56 of communication device 56C with ground equipment 300 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 explanation, communication satellite 201 is provided with communication device 55C, and communication satellite 202 is provided with communication device 56C, but both communication satellite 201 and communication satellite 202 may be provided with communication device 55C and communication device 56C.

[0040] <Transmission of monitoring information in monitoring system 501> 15 will be explained. Satellite information transmission system 600 shows communication satellite 201, communication satellite 202, and communication satellite 203. Communication satellite 203 does not have communication device 55C for communication satellite 201. The figure shows a situation in which monitoring information acquired by monitoring satellite 101 is transmitted in the order of communication satellite 201, communication satellite 203, communication satellite 202, and ground equipment 300 on Earth 400.

[0041] <Transmission of monitoring information in monitoring system 502> 16 will be explained. Satellite information transmission system 600 shows communication satellite 201, communication satellite 202, and communication satellite 203. The figure shows a situation in which monitoring information acquired by 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> 17 will be explained. Satellite information transmission system 600 shows communication satellite 201, communication satellite 202, and communication satellite 203. Monitoring information acquired by monitoring satellite 103 above the North Pole is transmitted to communication satellite 201 at the North Pole and ground facility 300. Monitoring information acquired by monitoring satellite 103 located to the right of monitoring satellite 103 above the North Pole is transmitted to communication satellite 201, communication satellite 202, and ground facility 300.

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

[0044] Embodiment 2 The second embodiment will be described with reference to Fig. 18 to Fig. 40. The second embodiment relates to an airborne object response system 700. The airborne object response system 700 is a combination of the monitoring system of the first embodiment and a satellite information transmission system. FIG. 18 shows a missile response system 700.

[0045] As shown in Figure 18, the airborne object response system 700 comprises a first data relay satellite 211 that flies above the equator at an orbital altitude of 2000 km or more, a second data relay satellite 212 that flies in a polar orbit at an orbital altitude of 2000 km or more, multiple monitoring satellites 100 that flies at an orbital altitude of 2000 km or less, a response device 310 that moves in the atmospheric airspace or on land or sea, and a response device 320 that is fixed to the ground. A monitoring satellite constellation consisting of multiple monitoring satellites 100 acquires monitoring information of flying object 333 launched from the ground and flying, and transmits the monitoring information to countermeasure devices 310, 320 via data relay satellites 211, 212. The countermeasure devices 310, 320 use the transmitted monitoring information to take countermeasure action against flying object 333.

[0046] The airborne object-enabled 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 compatible system 700, optical communication 71 and radio wave communication 72 are performed. The optical communication 71 and radio wave communication 72 shown in Fig. 18 are just an example. Combinations of optical communication 71 and radio wave communication 72 include, for example, the following variations (1) to (4). (1) At least one of a pair of first data relay satellites 211, a pair of second data relay satellites 212, and a pair of a first data relay satellite 211 and a second data relay satellite 212 performs optical communication 71.

[0048] (2) The data relay satellites 211 and 212 communicate with the monitoring satellite 100 via radio waves 72, and the data relay satellites 211 and 212 communicate with the countermeasure devices 310 and 320 via radio waves 72. 19 shows radio communication 72. From the left side of the figure, radio communication 72 is performed between a data relay satellite 212 and a monitoring satellite 100, radio communication 72 is performed between a data relay satellite 212 and another monitoring satellite 100, radio communication 72 is performed between a data relay satellite 211 and a monitoring satellite 100, and radio communication 72 is performed between a first data relay satellite 211 and a countermeasure device 310.

[0049] (3) The data relay satellites 211, 212 and the monitoring satellite 100 communicate by radio waves, the data relay satellites 211, 212 and the countermeasure devices 310, 320 communicate by optical waves, and the countermeasure devices 310, 320 transmit monitoring information to each other via a communication line 330. The communication line 330 will be described later with reference to FIG. FIG. 20 shows transmission using optical communication 71, radio communication 72, and communication line 330. 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, and the data relay satellite 211 and the monitoring satellite 100 perform radio communication 72. The first data relay satellite 211 performs optical communication 71 with the countermeasure device 320 and the second data relay satellite 212. FIG. 20 shows that a plurality of countermeasure devices 320 are connected by a communication line 330. The countermeasure devices 320 can exchange data via the communication line 330.

[0050] (4) The data relay satellites 211, 212 and the monitoring satellite 100 perform optical communication, the data relay satellites 211, 212 and the countermeasure devices 310, 320 perform optical communication, and the countermeasure devices 310, 320 transmit monitoring information via the communication line 330.

[0051] <Change of Azimuth and Elevation> FIG. 21 shows the change range of the communication field of view of Azimuth and Elevation of the optical communication device 220C provided in the data relay satellites 211, 212. At least one of the first data relay satellite 211 and the second data relay satellite 212 is provided with an optical communication device 220C. As shown in FIG. 21, the optical communication device 220C 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 data relay satellite, the communication field of view direction of Azimuth (XY plane) can be changed by 360 degrees with respect to the +Z axis direction, and the Elevation can be changed from 0 degrees to 80 degrees in the direction of the +Z axis with respect to the +X axis. This change range 221 is shown in FIG. 21. The triangular region 222 on the left side is the state where the change range 221 is rotated around the +Z axis. That is, the region 222 shows the change state of Azimuth (XY plane) of the change range 221. As shown in FIG. 21, due to the possibility of changing Azimuth and Elevation, the data relay satellites 211, 212 can perform optical communication with distant satellites with respect to the Earth 400.​​

[0052] Figure 22 shows the effect of changing the communication field of view of the optical communication device 220C between the data relay satellite 211 and the second data relay satellite 212. Area 223 shows the area obtained by rotating the elevation change range shown in Figure 21 in the azimuth direction. By changing the communication field of view direction, the first data relay satellite 211 becomes able to communicate optically with the distant second data relay satellite 212A. By changing the communication field of view direction, the second data relay satellite 212 becomes able to communicate optically with the distant second data relay satellite 212B. FIG. 23 shows a change in the communication field of view of the optical communication device 220C from the first data relay satellite 211, which is an equatorial satellite, to the second data relay satellite 212, which is a polar orbiting satellite. The area 225 showing the communication field of view may be rotated around the +Z axis, which is the azimuth direction, that is, the earth's center direction, after changing the elevation. Figure 23 shows the effect of changing the communication field of view.

[0053] Compared to FIG. 22, FIG. 24 shows that the communication field of view direction can be changed by 360 degrees in the Azimuth (XY plane) relative to the +Z axis direction, and by 0 to 70 degrees in the +Z axis direction relative to the +X axis. Figure 25 shows that, compared to Figure 22, the communication field of view direction can be changed by 360 degrees in the Azimuth (XY plane) relative to the +Z axis direction, and by 0 to 60 degrees in the +Z axis direction relative to the +X axis. Figures 24 and 25 are similar to Figure 22, so their explanation will be omitted.

[0054] 26 relates to the communication device 230C provided on 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. The direction of the +X axis, which faces the positive direction in the right-handed Cartesian coordinate system, is the satellite direction of travel of the data relay satellite +X. If the +Z axis, which points in the positive direction in the right-handed Cartesian coordinate system, is the geocentric direction of the data relay satellite, then ±10 degrees around the +X axis relative to the +Z axis, and, The field of view can be changed by ±10 degrees around the +Y axis, which points in the positive direction on a right-handed Cartesian coordinate system, relative to the +Z axis. The airborne object response system 700 uses the communication device 230C to communicate with the countermeasure device 310 moving in the atmospheric airspace, on land, or on the sea, or with the countermeasure device 320 fixed on the ground. In the case of the first data relay satellite 211 shown in FIG. 26, ±10 degrees around the +X axis relative to the +Z axis and ±10 degrees around the +Y axis relative to the +Z axis change the communication field of view by ±10 degrees in the vertical direction of the Earth 400, and ±10 degrees around the +Y axis relative to the +Z axis change the communication field of view by ±10 degrees in the horizontal direction of the Earth 400. FIG. 26 shows the communication fields of view 231, 232, which change within a ±10-degree range.

[0055] 27 shows that, compared to FIG. 26, communication device 230C can change the communication field of view by ±20 degrees around the +X axis relative to the +Z axis, and by ±20 degrees around the +Y axis relative to the +Z axis. Compared to Fig. 26, Fig. 28 shows that communication device 230C can change the communication field of view by ±30 degrees around the +X axis relative to the +Z axis, and by ±30 degrees around the +Y axis relative to the +Z axis. Figs. 27 and 28 are similar to Fig. 26, so their explanations will be omitted.

[0056] 18 may have the following configuration. The airborne object response system 700 includes a first data relay satellite 211 that flies above the equator at an orbital altitude of 2000 km or higher, a second data relay satellite 213 that is a sun-synchronous orbit satellite that flies in a sun-synchronous orbit, multiple monitoring satellites 100 that flies at an orbital altitude of 2000 km or lower, a countermeasure device 310 that moves in atmospheric airspace, on land, or on the sea, and a ground-based countermeasure device 320. The monitoring satellite group, which is the multiple monitoring satellites 100, acquires monitoring information on an airborne object 333 launched from the ground and transmits the monitoring information to the countermeasure devices 310 and 320 via the data relay satellites 211 and 213. The countermeasure devices 310 and 320 use the transmitted monitoring information to take countermeasure action against the airborne object 333.

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

[0058] 18 may include the following data relay satellites: The airborne system 700 may include a data relay satellite equipped with two sets of optical communication devices capable of changing the pointing direction in the Earth-pointing plane by an elevation rotation angle of 60 degrees or more and an azimuth rotation angle of 180 degrees or more. This data relay satellite will also: If the direction of the +X axis, which points in the positive direction in the right-handed Cartesian coordinate system, is the satellite flight direction +X of the data relay satellite, and the direction of the +Z axis, which points in the positive direction in the right-handed Cartesian coordinate system, is the geocentric direction +Z of the satellite, an optical communication device may be provided that changes the pointing direction by ±40 degrees around the +X axis relative to the +Z axis, and by ±40 degrees around the +Y axis, which points in the positive direction in the right-handed Cartesian coordinate system, relative to the +Z axis.

[0059] ***Effects of the second embodiment**** According to the second embodiment, the first data relay satellite 211 and the second data relay satellite 212 are linked together to transmit monitoring information to the countermeasure devices 310, 320, enabling information transmission without communication interruptions with a small number of communication satellites. The communication satellites of the airborne object support system 700 are capable of changing their communication field of view, enabling information transmission without communication interruptions with a small number of communication satellites. The airborne object support system 700 transmits monitoring information using a combination of optical communication 71 and radio wave communication 72, enabling smooth transmission of large amounts of data. According to the second embodiment, it is possible to take countermeasures against a flying object that changes its flight direction by intermittently boosting after launch. Furthermore, since data can be transmitted from the monitoring satellite to the countermeasure device only through space data transmission without the intervention of ground facilities, it is possible to take countermeasures in real time. Even if the missile travels a long distance from the launch site and the impact point is far away, data is transmitted by long-distance, high-capacity optical communications, which allows countermeasures to be taken at a remote location. Furthermore, by limiting the use of optical communications to data relay satellites, there is no risk of communication interruption.

[0060] <Supplementary information on the second embodiment> As mentioned in the background art, a system for dealing with HGVs is eagerly awaited. After launch, HGVs intermittently boost near the boundary between the upper atmosphere and space, making it difficult to estimate their flight path and impact point. Therefore, it is necessary to monitor their flight path until just before impact and transmit the data to a countermeasure device in near real time. With conventional projectiles, a high-temperature gas called a plume is dispersed during boost, making it possible to detect the temperature of the projectile using infrared light even at long distances from geostationary orbit. However, with HGVs, it is necessary to track their flight path after boost ends. To do this, the temperature of the heated aircraft is detected using infrared light. However, the temperature of the heated aircraft is not as high as that of the plume, and the area that heats up is small, so it is difficult to detect HGVs from long distances such as in geostationary orbit.

[0061] One effective method for tracking HGV flight is to monitor from close range using low-earth orbit (LEO) satellite constellations. By monitoring the aircraft against the backdrop of space using Earth edge surveillance, it is possible to track the aircraft without being obscured by background signals. In satellite-based aircraft surveillance systems deployed in high orbits, such as geostationary orbit and Molniya orbit, and used to observe and monitor a wide area of ​​the Earth, geostationary satellites, for example, can continuously monitor specific areas on the ground by taking advantage of their characteristic of orbiting in sync with the Earth. However, continuous surveillance using LEO satellite constellations requires the cooperation of multiple satellites, as each satellite's field of view is limited and it passes over a specific area in a short time. With a low-orbit satellite constellation, if there are a sufficient number of satellites, it will be possible to constantly monitor the entire Earth (hereinafter referred to as the "globe").By equipping it with infrared monitoring equipment that looks directly down to detect launches, and infrared monitoring equipment that points toward the Earth's edge and monitors the flying object against a space background after boost, it will be possible to detect the launch of an HGV and track its flight path after boost.

[0062] However, continuous global monitoring using a huge constellation of low-orbit satellites poses challenges, such as increasing total costs including satellite maintenance and launch costs, and requiring enormous amounts of satellite operation and data processing.

[0063] Coordination of equatorial, polar, and inclined orbit satellites is an effective means of achieving continuous global surveillance with as few satellites as possible. Equatorial satellites flying above the equator, although dependent on the orbital altitude, can comprehensively monitor the equatorial region with a nadir-looking system and the mid-latitude region with a periphery-of-earth system by evenly distributing a minimum of six satellites. Because polar orbit satellites pass through the polar regions on their entire orbit, polar orbit satellites can comprehensively monitor the polar region with a nadir-looking system and the mid-latitude region with a periphery-of-earth system by evenly distributing a minimum of six satellites in one orbital plane. Inclined orbit satellites, optimizing the orbital altitude, inclination, and satellite configuration allows for continuous monitoring of the mid-latitude region with a nadir-looking system and monitoring of the equator, the polar regions, and the high latitude region with a periphery-of-earth system.

[0064] After acquiring continuous global monitoring information from a constellation of 24 or more monitoring satellites, a means is required to transmit the data to a countermeasure device in real time. Therefore, in this application, data is transmitted to the countermeasure device via data relay satellites that fly in equatorial orbits and polar orbits at altitudes of 2000 km or higher. Satellites that fly at altitudes between 2000 km and 36,000 km are generally called medium earth orbit (MEO) satellites, while satellites that fly at an altitude of 36,000 km above the equator are geostationary (GEO) satellites. With geostationary satellites, three or more satellites evenly spaced longitude-wise can cover a communication range from the equator to the mid-latitudes. However, ensuring communication visibility in the polar regions remains a challenge.

[0065] Therefore, by linking with polar orbiting satellites, it will be possible to ensure constant communication lines around the globe. For mid-latitude satellites, it is necessary to select orbits that are not adversely affected by the Van Allen belts, but there is a track record of operating GPS satellite constellations at orbital altitudes of at least around 20,000 km, and there is also a track record of operating equatorial communication satellite constellations at orbital altitudes of around 8,000 km. The higher the orbital altitude, the wider the communication field of the atmosphere, which has the advantage of being able to cover the entire globe with a smaller number of satellites, but the issue of high latency (the time it takes to wait for communication) due to the long distances also comes with the issue that the amount of propellant required to reach a certain altitude after launch increases, which means that the satellite weight increases and the satellite equipped with the propellant tank becomes larger, which means that the number of satellites that can be launched simultaneously is limited.

[0066] A low orbital altitude has the advantage of reducing latency, shortening the time between detecting the launch of a projectile and transmitting data to a response device. This advantage means that less propellant is needed to launch and reach a specified altitude, making it easier to make satellites smaller and lighter, and increasing the number of satellites that can be launched simultaneously, which has the effect of reducing total costs even with a large number of satellites. However, there is the issue of increasing the number of satellites required to cover the entire globe.

[0067] To ensure constant communication coverage with low-orbit satellites at or below 2,000 km, as well as with countermeasures in atmospheric airspace, land, and sea, four or more data relay satellites with a communication field of view of ±30° along two orthogonal axes relative to the geocentric direction, operating in the same orbital plane, as shown in Figure 28, are required for data relay satellites operating at an orbital altitude of 8,000 km. For an orbital altitude of 36,000 km, three or more satellites with a communication field of view of ±10° along two orthogonal axes (+X and +Y axes) relative to the geocentric direction (+Z axis), operating in the same orbital plane, as shown in Figure 26, are required. Since multiple monitoring satellites measure the position of flying objects using the principle of spatial triangulation, two or more monitoring satellites can simultaneously transmit real-time data. Furthermore, considering the possibility of multiple flying objects being launched almost simultaneously, it is reasonable to deploy approximately six mid-latitude data relay satellites in the same orbital plane, with overlapping communication fields of view between the monitoring satellites and countermeasures. Figure 29 shows that if six data relay satellites are deployed above the equator at an orbital altitude of 20,000 km, the polar regions will become communication-dead areas, indicated by hexagons. Therefore, if six data relay satellites are similarly deployed in one polar orbital plane, as shown in Figure 27, it will be possible to ensure constant global communication links.

[0068] When a flying object flies a long distance, it may be rational to transmit data from the location where a surveillance satellite detected the launch to a response device near the area where the impact is expected via multiple data relay satellites. For long-distance communications between data relay satellites, it is rational to transmit large amounts of data via optical communications. In optical communications between any two first data relay satellites or any two second data relay satellites, the satellites fly synchronously at the same altitude within the same orbital plane, so the relative positions of the satellites do not fluctuate over time. Therefore, once optical communications are established by changing the pointing direction within the same orbital plane, stabilizing the pointing direction thereafter enables large-volume communications without interruption.

[0069] In contrast, in optical communications between the first data relay satellite and the second data relay satellite, the equatorial satellite moves in the longitude direction, while the polar satellite moves in the latitude direction, resulting in a wide range of variations in the relative positions of any two satellites.

[0070] Therefore, in this application, as shown in Figures 21 to 25, an elevation field-of-view change range within the same orbital plane is set that allows inter-satellite optical communication within the same orbital plane, and various line-of-sight changes are possible by azimuth rotation around the geocentric axis. For geostationary satellites, the maximum elevation angle change range is approximately 80 degrees from the satellite's flight direction toward the Earth, excluding the area in the Earth's shadow within the same orbital plane. Communication with nearby satellites in geostationary orbit is possible at an elevation angle of approximately 0 degrees, and communication with distant satellites in the Earth's shadow is possible at an elevation angle of approximately 80 degrees. If a first data relay satellite and a second data relay satellite with this field-of-view change range happen to be aligned in the same orbital plane, communication between any two satellites can be carried out with the same positional relationship.

[0071] In terms of elevation angle, when the orbital altitude is 20,000 km, the maximum range of the field of view that can be changed is about 72 degrees from the satellite's direction of flight toward the Earth, and when the orbital altitude is 8,000 km, the maximum range of the field of view that can be changed is about 63 degrees from the satellite's direction of flight toward the Earth.

[0072] Next, for communications between two satellites not in the same orbital plane, optical communications can be achieved in a variety of relative positions by rotating the azimuth around the Earth (+Z axis) and setting an appropriate elevation angle. Furthermore, even when the satellites are moving relative to each other, proper two-axis pointing control allows for continuous optical communications without interruption. Inter-satellite optical communications require precise alignment of the optical axes of both satellites, necessitating high pointing accuracy and stability. While current technology has demonstrated one-to-one optical communications, there are no examples of a single satellite simultaneously communicating with multiple satellites. Therefore, a communications interruption remains a risk in aerial vehicle-based systems that rely on simultaneous optical communications with multiple satellites. However, because the impact of a communications interruption would be devastating in aerial vehicle-based systems for security purposes, it is safer to limit simultaneous optical communications to one pair of crosslinks in order to ensure a reliable system.

[0073] Since communications between data relay satellites require long-distance, high-capacity communications, optical communications are the logical choice. However, radio communications are the logical choice for simultaneous communications between multiple monitoring devices and a single data relay satellite. By setting a wider beam spread angle, radio communications can improve tolerance to communication interruptions due to satellite movement, and a data relay satellite can simultaneously operate multiple radio communications devices. Furthermore, as has been demonstrated with positioning satellites such as GPS, it is possible to distinguish and utilize signals from multiple monitoring satellites transmitted and received from the same antenna. The same is true for data transmission from a single data relay satellite to multiple monitoring devices. Even when a single satellite simultaneously communicates with multiple monitoring satellites and multiple monitoring devices, radio communications enable real-time communication without communication interruptions. This is shown in Figure 19.

[0074] Regarding countermeasures, it may be reasonable to connect a group of countermeasures devices via a dedicated communications link and command and control them from a control tower. For example, in the case of the United States, a communications line called Link 16 has been established, and one idea is to transmit monitoring satellite data to an Aegis ship in bulk and command and control the response actions of multiple assets via Link 16. In this case, it would be reasonable to use optical communications for communication from the data relay satellite to the countermeasures device. If optical communications are sent to the countermeasures device after the monitoring information has been received from another data relay satellite, response actions can be carried out even if the optical crosslink between the data relay satellites is interrupted. This is shown in Figure 20.

[0075] Furthermore, once satellite attitude control technology with sufficient pointing accuracy and stability to simultaneously maintain optical crosslinks with multiple targets is established, it will become possible to use multiple optical communication devices for communication with surveillance satellites or countermeasures. For equatorial satellites, the direction of solar incidence rotates around the north-south axis during one longitude orbit around the Earth, making it reasonable to design solar array paddles with a rotation function around the north-south axis (Y-axis). In contrast, for polar orbiting satellites, the direction of solar incidence rotates along the elevation axis during one latitude orbit around the Earth, and the normal vector to the orbital plane rotates along the azimuth axis, resulting in lower solar array efficiency compared to equatorial satellites. Fixed or single-axis rotating solar array paddles require larger solar array paddles, and to improve solar array efficiency, they must be equipped with a two-axis rotation function. To address this issue, a sun-synchronous orbit, known as a Dawndusk orbit, in which the normal vector to the orbital plane is always pointed toward the Earth, allows fixed solar array paddles to always be pointed toward the sun. Sun-synchronous conditions are correlated with orbital altitude and orbital inclination, and the lower the orbit, the closer the orbital inclination is to 90 degrees, so low Earth orbit (LEO) satellites are polar orbits. Up to an orbital altitude of about 5,000 km, a sun-synchronous orbit can be achieved by natural laws alone, but the further the orbital inclination deviates from 90 degrees, the greater the constraints on continuous polar monitoring. It is possible to increase the variety of orbital altitudes and orbital inclinations that maintain sun-synchronous conditions by artificially operating the propulsion system, but this requires propellant, so determining the optimal conditions depends on the system design policy. Figure 30 shows the orbital altitude and orbital inclination that maintain the sun-synchronous condition. The sun 810 is shown in Figure 30. Figure 30 shows the following five pairs (1) to (5). (1) Orbital altitude approximately 5000km, orbital inclination approximately 139 degrees, latitude approximately 41 degrees, (2) Orbital altitude approximately 4000km, orbital inclination approximately 123 degrees, latitude approximately 57 degrees (3) Orbital altitude approximately 3000km, orbital inclination approximately 112 degrees, latitude approximately 68 degrees (4) Orbital altitude approximately 2000km, orbital inclination approximately 105 degrees, latitude approximately 75 degrees (5) Orbital altitude approximately 1000km, orbital inclination approximately 100 degrees, latitude approximately 80 degrees.

[0076] Embodiment 3 The third embodiment relates to a system of 24 or more satellites in total, including six or more satellites in polar orbits, six or more satellites in equatorial orbits, and 12 or more satellites in inclined orbits.

[0077] The third embodiment relates to a monitoring system 3000 consisting of multiple monitoring satellites equipped with a first monitoring device pointing toward the Earth's surface and a second monitoring device pointing toward the Earth's periphery, and ground facilities. The monitoring system 3000 forms a satellite constellation with a group of polar orbit satellites of six or more monitoring satellites flying at an inclination of 80 degrees or more, a group of inclined orbit satellites of 12 or more monitoring satellites flying in inclined orbits of 10 degrees to 80 degrees, and a group of equatorial satellites of six or more monitoring satellites flying above the equator at an inclination of less than 10 degrees.

[0078] The monitoring system 3000 will be described. The global coverage achieved by a first monitoring device oriented toward the geocenter will be described. Polar-orbiting satellites pass through the polar regions every orbit, so six or more satellites alternate in one orbital plane, enabling the first monitoring device to continuously monitor the polar regions. However, coverage cannot be ensured from mid-latitudes to low latitudes. Equatorial satellites, with six or more satellites alternate in one orbital plane, enable the first monitoring device to continuously monitor areas near the equator. However, monitoring from mid-latitudes to high latitudes is not possible. Inclined-orbit satellites offer enormous diversity depending on the combination of orbital altitude, orbital inclination, field-of-view settings of the first monitoring device, and number of satellites. However, it has been shown that a constellation of two or more satellites can ensure comprehensive observation of the mid-latitudes by the first monitoring device. However, polar regions cannot be monitored, and continuous monitoring above the equator may be impossible, resulting in a lack of comprehensiveness. The monitoring system 3000 has the effect of ensuring global coverage by the first monitoring device with a small number of satellites, as the polar orbiting satellites, the equatorial satellites, and the inclined orbit satellites complement each other.

[0079] Next, we will explain the global airspace coverage provided by the second monitoring system, which is aimed at the Earth's periphery. Since HGVs are known to fly at low altitudes of approximately 100 km or less after launch, the altitude range over the global airspace can be limited to the highest altitude possible before lowering its altitude after launch. The field of view of the second monitoring system, which uses polar-orbiting satellites, can cover high latitudes above 60 degrees north and 60 degrees south when passing near the polar regions. The field of view of the second monitoring system, which uses equatorial satellites, extends to the mid-latitudes of the northern and southern hemispheres, and the latitude range to be monitored can be set by selecting the orbital altitude and orbital inclination. The inclined-orbit satellites can ensure a wide monitoring area, including above the polar regions and above the equator. The monitoring system 3000 allows the polar-orbiting satellites, equatorial satellites, and inclined-orbit satellites to complement each other, thereby ensuring global coverage by the second monitoring system with a smaller number of satellites. The effect of this system is that a minimum of 24 satellites will enable detection of the launch of a flying object and tracking of the object during flight. Simultaneous monitoring by multiple satellites will enable spatial triangulation to calculate the position coordinates of the flying object.

[0080] If infrared sensors are used for the first and second monitoring devices, the first monitoring device can be pointed toward the Earth's center and ensure a field of view extending to the Earth's tangent, enabling it to detect the high-temperature plume emitted during launch. If the second monitoring device is pointed toward the Earth's edge and has a 360-degree field of view around the azimuth axis relative to the Earth's center, like a fisheye camera, the instantaneous field of view will be ring-shaped, enabling it to cover a wide area as the satellite moves. Earth edge monitoring allows monitoring of the space background as the vehicle flies above the Earth, making it possible to detect the temperature of the vehicle after the end of the thrust, which is not as high as the high-temperature plume. This makes it possible to track the flight path after the thrust ends. It is known that HGVs change their flight direction by operating their propulsion systems again during flight, and the second monitoring device can detect the thrust during flight and track it after the change. FIG. 31 conceptually illustrates monitoring by a second monitoring device.

[0081] <Explanation of the comprehensiveness of the first monitoring device> Figures 32 and 33 show the comprehensiveness of the first monitoring device. For the purpose of comprehensively monitoring the area near the equator on the Earth's surface, if six satellites are evenly spaced in equatorial orbit, each first monitoring device pointing toward the Earth's center can cover a monitoring range of 60 degrees of longitude, enabling continuous monitoring of the area near the equator. If the orbital altitude is 1,000 km, a first monitoring device with a field of view of ±60 degrees in the longitude direction relative to the Earth's center can be provided. If specific monitoring points can be limited within the 60-degree longitude range, a field of view change function that allows the line of sight to be changed within ±60 degrees may be provided. Furthermore, if continuous monitoring of the entire 60-degree longitude range is required, multiple monitoring devices may be mounted on a single satellite, or the number of satellites may not be limited to six, and the number of satellites in the same orbital plane may be increased depending on the field of view of the monitoring device. To achieve continuous monitoring covering the entire surface of the Earth's surface near the equator, it is necessary to overlap the monitoring area with satellites flying before and after in the same orbit, so deploying eight or more satellites makes it easier to build a system. Also, by increasing the orbital altitude, it is possible to find a viable solution that narrows the field of view of the monitoring equipment.

[0082] Figure 34 shows a schematic diagram of the monitoring range of a polar-orbiting satellite. Using a similar concept, in a polar orbit with an inclination of 80 degrees or more, six or more satellites are evenly distributed in the same orbital plane, and if a first monitoring device can secure a field of view of ±60 degrees from the center of the earth in the direction of travel from an orbital altitude of 1,000 km, continuous monitoring of the Earth's surface can be achieved around the circumference of that orbital plane. Polar-orbiting satellites pass through the polar regions on every orbit, so if six satellites are evenly distributed in one orbital plane, continuous monitoring of the polar regions can be achieved by the movement of the orbital plane relative to the earth as the Earth rotates.

[0083] Figure 35 shows a schematic diagram of the monitoring range of a polar orbiting satellite. There is a known satellite constellation that can comprehensively monitor the mid-latitudes using 12 or more satellites flying at an altitude of about 2000 km in an inclined orbit set at an inclination angle of about 45 degrees. If the number of satellites is increased, comprehensive monitoring of the mid-latitudes will be possible even at an orbital altitude of 1000 km.

[0084] Figure 36 shows the coverage of the first monitoring device. While the equatorial satellite constellation, polar orbiting satellite constellation, and inclined orbiting satellite constellation cannot cover the entire globe individually, combining these three satellite constellations enables comprehensive, constant global monitoring by the first monitoring device. Furthermore, global coverage is possible with a minimum of 24 satellites, reducing system maintenance costs. As a result, the first infrared sensor enables detection of the launch of a flying object. Furthermore, the second infrared sensor detects the temperature of the flying object after its injection, enabling flight tracking. Furthermore, in areas where multiple satellites can simultaneously monitor, the position coordinates of the flying object can be derived using the principle of spatial triangulation.

[0085] <Explanation of the comprehensiveness of the second monitoring device> 37 and 38 are diagrams for explaining the coverage of the second monitoring device. Next, we will show the coverage of the field of view of the second monitoring device pointing toward the edge of the Earth. For a satellite above the equator, the field of view covers the mid-latitudes of the northern hemisphere and the southern hemisphere, and by orbiting the equator, the mid-latitudes are covered in a ring-shaped monitoring area.

[0086] Figures 39 and 40 show polar-orbiting satellites. Polar-orbiting satellites have a field of view near 60 degrees north latitude when passing near the North Pole, and near 60 degrees south latitude when passing near the South Pole. By flying in a north-south direction, a ring-shaped field of view is formed when viewed from the equator. Even if the orbital plane is uniform, the monitoring area moves over time due to the effect of the Earth's rotation. If the second monitoring device has a 360-degree field of view around the azimuth axis in the geocentric direction, like a fisheye camera, a single satellite will cover a ring-shaped area from the North Pole to near 60 degrees north latitude. Polar-orbiting satellites pass through the polar regions every orbit, so even if they have a single orbital plane, six or more satellites will alternately fly, ensuring constant coverage of areas near 60 degrees north latitude and near 60 degrees south latitude. Furthermore, forward and backward views before and after passing the polar regions ensure constant coverage of high latitudes above 60 degrees.

[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 is formed in a cross-shaped ring shape, including the polar regions and the equator. Furthermore, since the inclined orbit satellites are evenly distributed in the longitude direction, the field of view formed by the inclined orbit satellites covers almost the entire globe.

[0088] Figure 43 shows the global coverage provided by the second monitoring device. Figure 43 shows the monitoring field of view of only satellites angled toward the second monitoring device. In reality, as shown in Figure 37, the area that can be monitored by the monitoring field of view can be strip-shaped on the Earth's surface. By combining the field of view provided by the second monitoring device of the equatorial satellites, polar orbit satellites, and inclined orbit satellites, global coverage is ensured. Furthermore, because the fields of view of multiple satellites overlap at the same time, stereoscopic vision by spatial triangulation becomes possible, making it possible to calculate flight position coordinates.

[0089] The monitoring system 3000 of the third embodiment is as follows. The monitoring system 3000 comprises multiple monitoring satellites and ground facilities, each equipped with a first monitoring device pointing toward the Earth's surface and a second monitoring device pointing toward the Earth's periphery. Six or more monitoring satellites form a satellite constellation as a group of equatorial satellites flying above the equator at an orbital inclination angle of less than 10 degrees. In this monitoring system 3000, the orbit is elliptical, and the monitoring range of the second monitoring device expands toward higher latitudes near the apogee and toward lower latitudes near the perigee. Figures 44 and 45 show the relationship between orbital latitude and the Earth tangent. According to this monitoring system 3000, At an orbital altitude of approximately 400 km, the tangent direction is 20 degrees north latitude. At an orbital altitude of approximately 1000 km, the tangent direction is 30 degrees north latitude. At an orbital altitude of approximately 2000 km, the tangent direction is 40 degrees north latitude. At an orbital altitude of approximately 3,600 km, the tangent direction is 50 degrees north latitude. At an orbital altitude of approximately 12,800 km, the tangent direction is 60 degrees north latitude. Each can be monitored against the cosmic background. Therefore, by adopting an elliptical orbit above the equator and setting the apogee as the upper limit of high latitudes and the perigee as the lower limit of low latitudes, the desired monitoring range can be covered. If the equatorial satellites are numbered sequentially, the observation range can be rationally expanded by alternating the orbital planes so that odd-numbered satellites are at apogee and even-numbered satellites are at perigee. Since the major axis of an elliptical orbit rotates within the orbital plane, in order to monitor a specific monitoring area at a specific local sun time (LST), the major axis can be positioned appropriately at that LST, and the monitoring range can be maintained by creating a frozen orbit. While achieving a frozen orbit solely through natural phenomena places significant constraints on the orbital parameters, operating a propulsion system allows for a high degree of freedom in parameter setting.

[0090] In the monitoring system 3000 of the third embodiment, the track may be a frozen track.

[0091] The monitoring system 3000 of the third embodiment may also have the following configuration. The monitoring system 3000 includes multiple monitoring satellites, each equipped with a first monitoring device pointing toward the Earth's surface and a second monitoring device pointing toward the Earth's periphery, and ground equipment. In the monitoring system 3000, six or more monitoring satellites form a satellite constellation as a group of equatorial satellites flying above the equator at an orbital inclination angle of less than 10 degrees. In the monitoring system 3000, the orbit is elliptical, and the monitoring range of the second monitoring device is expanded to high latitudes in the Northern Hemisphere and low latitudes in the Southern Hemisphere at the northernmost end of the orbit, and to high latitudes in the Southern Hemisphere and low latitudes in the Northern Hemisphere at the southernmost end of the orbit.

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

[0093] All of the satellites featured in the first to third embodiments are controlled by a control device or a management device located on Earth.

[0094] The first to third embodiments have been described above. Two or more of these embodiments 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. [Explanation of symbols]

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

Claims

1. A system comprising a group of monitoring satellites flying at an orbital altitude of 2000 km or less, a countermeasure device that moves in the airspace of the atmosphere, on land or on the sea, or is fixed on the ground, and a data relay satellite that relays monitoring information acquired by the group of monitoring satellites to the countermeasure device, The data relay satellites include a data relay satellite that flies above the equator at an orbital altitude of 2000 km or more, and a data relay satellite that flies in a polar orbit at an orbital altitude of 2000 km or more, The data relay satellite The flying object response system includes 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 with respect to the +Z axis, where the direction of the +X axis that points in the positive direction in the right-handed Cartesian coordinate system is defined as the satellite's direction of flight, +X, and the direction of the +Z axis that points in the positive direction in the right-handed Cartesian coordinate system is defined as the satellite's direction of flight, +Z, and the optical communication device transmits the monitoring information to the response device in real time without using ground equipment.

2. A data relay satellite provided in the airborne object response system described in claim 1.

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