Projectile Tracking System

Abstract

To provide a missile tracking system which can improve derivation accuracy of a missile position coordinate by stereoscopic vision in a low orbit satellite constellation of several-ten scale.SOLUTION: In a satellite constellation 20 which constitutes a missile tracking system 500, each monitoring satellite 120 includes an infrared monitoring device which directs the globe periphery. The satellite constellation 20 flies on an inclined orbit, and monitors and tracks a missile by using missile launching detection information as trigger. In the satellite constellation 20, six or more satellites respectively fly on four or more orbit planes which have orbit altitude of 900 to 2000 km, orbit inclination angle of 20±10° and normal vectors uniformly dispersed in the latitude direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a technique for tracking the flight trajectory of a flying object. [Background technology]

[0002] There are missile defense systems that are based on the assumption that the missile will travel on a ballistic trajectory. The projectile countermeasure system detects the spray (plume) at launch with an infrared observation device mounted on a geostationary orbit satellite, predicts the landing position based on movement information from the early stage of flight, and responds with the countermeasure system. At launch, extremely high temperature gas spreads over a wide area. Therefore, it is possible to detect a projectile even by monitoring from geostationary orbit.

[0003] Recently, however, a new threat has emerged: a flying object called a Hypersonic Glide Vehicle (HGV), which changes its flight path by intermittently ejecting gas during flight. In order to track a flying object that has stopped firing, it is necessary to detect the temperature of the flying object itself, which requires high-resolution and high-sensitivity infrared monitoring, which is not possible with conventional geostationary satellite monitoring.

[0004] Research has therefore begun into a system that would use low-orbit satellite constellations to monitor flying objects from much closer distances than geostationary orbit. There is a strong demand for a system that would provide constant monitoring using a constellation of low-orbiting satellites and immediately transmit information to response assets upon detection of a missile launch. A low earth orbit satellite constellation is a satellite constellation made up of a group of low earth orbit satellites. A low earth orbit constellation is one or more low earth orbit satellites. A low-earth orbit satellite is an artificial satellite that flies in a low orbit, such as LEO. LEO is an abbreviation for Low Earth Orbit.

[0005] Patent Document 1 discloses a monitoring satellite that orbits in a low orbit and comprehensively monitors an area at a specific latitude on the Earth's surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4946398 Summary of the Invention [Problem to be solved by the invention]

[0007] A launch detection and tracking system using a constellation of several hundred low-earth orbit satellites is under consideration, but the cost is an issue. Therefore, a low-earth orbit satellite constellation with a smaller number of satellites is desired, and there is a concept of a limb monitoring and flying object tracking system using a constellation of several dozen low-earth orbit satellites from an equatorial orbit. However, there was a problem with the equatorial orbit, in that the accuracy of the latitudinal direction in deriving the aircraft position coordinates using stereoscopic vision was poor.

[0008] The present disclosure aims to improve the accuracy of deriving flight position coordinates through stereoscopic vision in low-earth-orbit satellite constellations of several tens of satellites. [Means for solving the problem]

[0009] The flying object tracking system according to the present disclosure is a flying object tracking system that is configured by a satellite constellation flying in an inclined orbit, each satellite having an infrared monitoring device directed toward the Earth's periphery, and monitors and tracks the flying object using flying object launch detection information that detects the launch of the flying object as a trigger, The satellite constellation has an orbital altitude of 900 km or more and 2000 km or less, an orbital inclination angle of 20±10 degrees, and six or more satellites fly on each of four or more orbital planes with normal vectors evenly distributed in the longitude direction. Effect of the Invention

[0010] The flying object tracking system according to the present disclosure has the advantage of enabling tracking of flying objects in the mid-latitudes using several dozen satellites, while also improving the accuracy of deriving flying position coordinates through stereoscopic vision of multiple satellites. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a configuration example of a flying object tracking system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a monitoring satellite according to the first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of a hardware configuration of the ground system according to the first embodiment. [Figure 4] FIG. 2 is a diagram showing an example of functions of the flying object tracking system according to the first embodiment. [Diagram 5] FIG. 1 is a diagram showing a configuration example of a flying object tracking system according to a first embodiment. [Figure 6] FIG. 2 is a diagram showing the concept of stereoscopic vision using equatorial orbiting satellites for comparison with the flying object tracking system according to the first embodiment. [Figure 7] FIG. 2 is a diagram showing the concept of stereoscopic vision using satellites in inclined or polar orbits for comparison with the flying object tracking system according to the first embodiment. [Figure 8] FIG. 1 is a diagram showing a satellite constellation in equatorial orbit according to a first embodiment. [Figure 9] FIG. 2 is a diagram showing a satellite constellation in an equatorial orbit inclined at an orbital inclination angle of 20 degrees according to the first embodiment. [Figure 10] FIG. 2 is a diagram showing the concept of stereoscopic vision in a satellite constellation in an equatorial orbit with an orbital inclination angle of 20 degrees according to the first embodiment. [Figure 11] 4 is a diagram showing derivation of flying position coordinates according to the principle of spatial triangulation in the flying object tracking system according to the first embodiment. FIG. [Figure 12] FIG. 1 is a diagram showing a first configuration example of a flying object tracking system according to a first embodiment. [Figure 13]FIG. 2 is a diagram showing the configuration example 2 of the flying object tracking system according to the first embodiment as viewed from the North Pole. [Figure 14] FIG. 2 is a diagram showing a second configuration example of the flying object tracking system according to the first embodiment, as viewed from above the equator. [Figure 15] FIG. 3 is a diagram showing a configuration example 3 of the flying object tracking system according to the first embodiment. [Figure 16] FIG. 4 is a diagram showing a fourth configuration example of the flying object tracking system according to the first embodiment. [Figure 17] FIG. 5 is a diagram showing a configuration example 5 of the flying object tracking system according to the first embodiment. [Figure 18] FIG. 2 is a diagram showing an example of transmission of satellite information in the flying object tracking system according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of the embodiments, the description of the same or corresponding parts will be omitted or simplified as appropriate. In addition, the relationship between the sizes of the components in the following drawings may differ from the actual relationship. In addition, in the description of the embodiments, directions or positions such as "upper", "lower", "left", "right", "front", "rear", "front" and "back" may be indicated. These notations are written in this way only for the convenience of explanation, and do not limit the arrangement and orientation of the components such as devices, instruments, or parts.

[0013] Embodiment 1 ***Configuration Description*** FIG. 1 is a diagram showing an example of the configuration of a flying object tracking system 500 according to the present embodiment.

[0014] The flying object tracking system 500 is a system for tracking the flight trajectory of the flying object 600. The flying object tracking system 500 tracks the flight trajectory of the flying object 600 by rim monitoring.

[0015] The airborne object tracking system 500 includes a satellite constellation 20 and a ground system 130. The satellite constellation 20 includes a number of monitoring satellites 120 . The monitoring satellite 120 is an artificial satellite for monitoring the flying object 600. The monitoring satellite 120 may also be simply called a satellite.

[0016] FIG. 2 is a diagram showing an example of the configuration of the monitoring satellite 120 according to this embodiment. The monitoring satellite 120 includes a communication device 121 , a monitoring device 122 , a propulsion device 123 , an attitude control device 124 , a satellite control device 125 , and a power supply device 126 .

[0017] The communication device 121 is a communication device for communicating with the ground system 130. For example, the communication device 121 receives various commands from the ground system 130. In addition, the communication device 121 transmits monitoring data obtained by the monitoring device 122 to the ground system 130.

[0018] The monitoring device 122 is a device for monitoring the flying object 600 and generates monitoring data. The monitoring device 122 is an infrared monitoring device that uses infrared rays. Surveillance device 122 is an example of an infrared surveillance device aimed at the edge of the Earth. The monitoring satellite 120 has a pointing function for directing the line of sight toward the flying object 600 .

[0019] The monitoring data corresponds to an image showing the flying object 600, and indicates the position of the flying object 600 within the field of view (monitoring range) of the monitoring device 122. The monitoring data may include time information, location information, line-of-sight information, and field-of-view information. The time information indicates the time when monitoring was performed (monitoring time). The location information indicates the coordinate values ​​of the monitoring satellite 120. The line-of-sight information indicates the line-of-sight direction of the monitoring device 122. The field-of-view information indicates the field of view of the monitoring device 122.

[0020] The propulsion device 123 is a device that provides thrust to the monitoring satellite 120 and changes the speed of the monitoring satellite 120. Specifically, the propulsion device 123 is an electric propulsion device. For example, the propulsion device 123 is an ion engine or a Hall thruster.

[0021] The attitude control device 124 is a device for controlling attitude elements such as the attitude of the monitoring satellite 120 and the angular velocity of the monitoring satellite 120 . The attitude control device 124 changes each attitude element to a desired direction. Alternatively, the attitude control device 124 maintains each attitude element in a desired direction. The attitude control device 124 includes an attitude sensor, an actuator, and a controller. The attitude sensor is a gyroscope, an earth sensor, a sun sensor, a star tracker, a thruster, a magnetic sensor, etc. The actuator is an attitude control thruster, a momentum wheel, a reaction wheel, a control moment gyro, etc. The controller controls the actuator according to measurement data of the attitude sensor or various commands from the ground system 130. The attitude control device 124 can be used as a device (field of view direction changing device) for changing the field of view direction of the monitoring device 122. The field of view direction of the monitoring device 122 corresponds to the line of sight direction of the monitoring device 122. The range (field of view) centered on the line of sight direction of the monitoring device 122 becomes the monitoring range.

[0022] The satellite control device 125 is a computer and includes a processing circuit that controls each device of the monitoring satellite 120. For example, the satellite control device 125 controls each device according to various commands transmitted from the ground system .

[0023] The power supply unit 126 includes a solar cell, a battery, a power control device, and the like, and supplies power to each device of the monitoring satellite 120 .

[0024] Returning to FIG. 1, the configuration of the ground system 130 will be described. The ground system 130 includes a communication device 950 and a satellite control device 132 . The satellite control device 132 is a computer equipped with hardware such as a processing circuit and an input / output interface. An input device and an output device are connected to the input / output interface. The satellite control device 132 is connected to a communication device 950 via the input / output interface. The satellite control device 132 generates various commands for each monitoring satellite 120 in order to control the satellite constellation 20. The satellite control device 132 also analyzes monitoring data obtained from each monitoring satellite 120 to generate information (e.g., position information) of the flying object 600. The communication device 950 communicates with each monitoring satellite 120. Specifically, the communication device 950 transmits various commands to each monitoring satellite 120. In addition, the communication device 950 receives monitoring data transmitted from each monitoring satellite 120.

[0025] The processing circuits provided in each of the satellite control unit 132 and the satellite control device 125 will now be described. The processing circuitry may be dedicated hardware or may be a processor that executes a program stored in a memory. In the processing circuit, some functions may be realized by dedicated hardware and the remaining functions may be realized by software or firmware, i.e. the processing circuit may be realized by hardware, software, firmware or a combination thereof. The dedicated hardware may be, for example, a single circuit, multiple circuits, a programmed processor, parallel programmed processors, an ASIC, an FPGA, or a combination of these. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array.

[0026] The adjustment of satellite altitude and orbital inclination is explained. The relative angle of the normal to the orbital plane of the monitoring satellite 120 as viewed from the North Pole is determined by the correlation between the satellite altitude and the orbital inclination angle. By fine-tuning the orbital inclination angle appropriately under altitude conditions that maintain the number of satellite orbits per day, it is possible to operate the 20 satellite constellation while maintaining the relative angle between the orbital planes. The satellite control device 132 generates commands for controlling the altitude of each monitoring satellite 120. The satellite control device 132 also generates commands for controlling the orbital inclination angle of each monitoring satellite 120. Then, the satellite control device 132 transmits these commands to each monitoring satellite 120. In each monitoring satellite 120, the satellite controller 125 adjusts the satellite altitude and the orbital inclination according to these commands. Specifically, the satellite controller 125 controls the propulsion device 123 according to these commands. The propulsion device 123 can adjust the satellite altitude and the orbital inclination by changing the satellite speed. When the flight speed of the monitoring satellite 120 increases, the altitude of the monitoring satellite 120 increases. When the altitude of the monitoring satellite 120 increases, the ground speed of the monitoring satellite 120 decreases. When the flight speed of the monitoring satellite 120 decreases, the altitude of the monitoring satellite 120 decreases. And when the altitude of the monitoring satellite 120 decreases, the ground speed of the monitoring satellite 120 increases. If the propulsion device 123 generates thrust in a direction perpendicular to the orbital plane at the point (equinox) where the monitoring satellite 120 crosses the equator, the orbital inclination angle can be effectively fine-tuned.

[0027] ***Hardware Description*** FIG. 3 is a diagram showing an example of a hardware configuration of the ground system 130 according to this embodiment. The hardware included in the computer will be described using the ground system 130 as an example.

[0028] The processor 910 is a device that executes a program that realizes the functions of the ground system 130 . The processor 910 is an integrated circuit (IC) that performs arithmetic processing. Specific examples of the processor 910 include a central processing unit (CPU), a digital signal processor (DSP), and a graphics processing unit (GPU).

[0029] The memory 921 is a storage device that temporarily stores data. Specific examples of the memory 921 include a static random access memory (SRAM) and a dynamic random access memory (DRAM). The auxiliary storage device 922 is a storage device that stores data. A specific example of the auxiliary storage device 922 is a HDD. The auxiliary storage device 922 may also be a portable storage medium such as an SD (registered trademark) memory card, CF, NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, or a DVD. Note that HDD is an abbreviation for Hard Disk Drive. SD (registered trademark) is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash (registered trademark). DVD is an abbreviation for Digital Versatile Disk.

[0030] The input interface 930 is a port connected to an input device such as a mouse, a keyboard, or a touch panel. Specifically, the input interface 930 is a Universal Serial Bus (USB) terminal. The input interface 930 may be a port connected to a Local Area Network (LAN). The output interface 940 is a port to which a cable of a display device 941 such as a display is connected. Specifically, the output interface 940 is a USB terminal or an HDMI (registered trademark) (High Definition Multimedia Interface) terminal. Specifically, the display is an LCD (Liquid Crystal Display).

[0031] The communication device 950 includes a receiver and a transmitter, and is specifically a communication chip or a network interface card (NIC).

[0032] A program that realizes the functions of the ground system 130 is read into the processor 910 and executed by the processor 910. In addition to the program, an OS (Operating System) is also stored in the memory 921. The processor 910 executes the program while executing the OS. The program and the OS may be stored in an auxiliary storage device 922. The program and the OS stored in the auxiliary storage device 922 are loaded into the memory 921 and executed by the processor 910. Note that a part or all of the program that realizes the functions of the ground system 130 may be incorporated into the OS.

[0033] The ground system 130 may include multiple processors that replace the processor 910. These multiple processors share the task of executing a program. Each processor, like the processor 910, is a device that executes a program.

[0034] Data, information, signal values ​​and variable values ​​used, processed or output by the programs are stored in the memory 921, the secondary storage device 922, or in registers or cache memory within the processor 910.

[0035] The "parts" of the parts of the ground system 130 may be read as "processing," "procedure," "means," "steps," "circuitry," or "steps." Also, the "parts" of the parts of the ground system 130 may be read as "program," "program product," or "computer-readable recording medium on which a program is recorded." "Processing," "procedure," "means," "steps," "circuitry," or "steps" may be read as mutually interchangeable.

[0036] ***Functional Overview of the Aircraft Tracking System 500*** FIG. 4 is a diagram showing an example of functions of a flying object tracking system 500 according to this embodiment.

[0037] The airborne object tracking system 500 is composed of a satellite constellation 20 flying in an inclined orbit. In the satellite constellation 20, each satellite is equipped with an infrared monitoring device pointing toward the edge of the Earth. The airborne object tracking system 500 monitors and tracks an airborne object 600 using airborne object launch detection information as a trigger. The airborne object launch detection information is information that detects the launch of the airborne object 600.

[0038] When the flying object 600 is launched, high-temperature air is dispersed, making it easy to monitor. However, the solid angle of the flying object body in the post-boost phase that can be seen from the monitoring satellite 120 is small, and the temperature rise is not as significant as in the plume. Therefore, if information about the land area in the background is mixed with the flying object information, there is a concern that it will be impossible to identify the flying object. The post-boost phase is the phase after the jet stops. Therefore, a monitoring method called limb observation, which is aimed toward the edge of the Earth, will be used to monitor the heated body of the spacecraft against the backdrop of deep space. This makes it possible to monitor flying objects without the flying object information being buried in noise.

[0039] The position coordinates (coordinate values) of the flying object 600 are derived by the principle of spatial triangulation. Specifically, the flying object 600 is simultaneously monitored by three monitoring satellites 120 whose position coordinates are known. At this time, the position coordinates (coordinate values) of the flying object 600 can be analyzed as a point where the line-of-sight vectors of the monitoring satellites 120 meet, based on the azimuth angle (line-of-sight direction) of the line-of-sight vector of each monitoring satellite 120. The greater the dispersion of the azimuth angles of the line-of-sight vectors seen from the flying object 600, the more the position measurement accuracy improves.

[0040] The satellite control device functions as a flight path prediction device that integrates flying object information indicating high-temperature objects detected by multiple monitoring satellites and analyzes changes in position information over time, making it possible to track flying objects and predict their flight paths. Even if the flying object intermittently re-injects and changes direction during flight, the flight path prediction device tracks the direction of travel and continuously acquires time-series information, making it possible to take action against the flying object.

[0041] ***Description of the flying object tracking system 500 according to this embodiment*** FIG. 5 is a diagram showing an example of the configuration of a flying object tracking system 500 according to this embodiment. The airborne object tracking system 500 according to the present embodiment is configured with a satellite constellation 20. Each monitoring satellite 120 of the satellite constellation 20 is equipped with an infrared monitoring device that is directed toward the edge of the Earth. The satellite constellation 20 flies in an inclined orbit. The flying object tracking system 500 monitors and tracks the flying object 600 using the flying object launch detection information that detects the launch of the flying object 600 as a trigger. The airborne object tracking system 500 is configured with a satellite constellation 20 in which six or more satellites fly in each of four or more orbital planes. The orbital altitude of each orbit is between 900 km and 2000 km. The inclination angle of each orbit is 20±10 degrees. In addition, the normal vectors of each orbit are evenly distributed in the longitude direction.

[0042] FIG. 6 is a diagram showing the concept of stereoscopic vision by a satellite in equatorial orbit for comparison with the flying object tracking system 500 according to this embodiment.

[0043] Since it is no longer possible to deal with flying objects by detecting launches from geostationary orbit alone, there is a need for a flying object tracking system using a constellation of low-earth-orbit satellites. It is said that several hundred satellites are needed to maintain a constant, global surveillance system, which could result in an extremely expensive system. On the other hand, a satellite constellation has been proposed that can track flying objects in the mid-latitudes using a small number of satellites (approximately 10) by forming a constellation of satellites in a linked fashion above the equator. However, in the case of satellite constellations above the equator, when deriving flight position coordinates from stereo pair images taken by multiple satellites simultaneously monitoring flying objects, the relative angle of the line-of-sight vectors used to obtain the stereo pair images is small, which poses the problem of large measurement errors in the latitudinal direction.

[0044] FIG. 7 is a diagram showing the concept of stereoscopic vision using satellites in inclined or polar orbits for comparison with the flying object tracking system 500 according to this embodiment. On the other hand, satellite constellations with inclined or polar orbits can acquire stereo pair images with a large relative angle of the line of sight vector. This has the effect of deriving highly accurate coordinates of the flying object's position using the principle of spatial triangulation. However, there is a problem in that a large number of satellites (more than 100) are required to build a surveillance system using a satellite constellation with an inclined or polar orbit.

[0045] Therefore, in this embodiment, there is provided a flying object tracking system 500 that tracks a flying object flying in the mid-latitudes using a constellation of 100 or less satellites. In this embodiment, taking advantage of the advantages of the equatorial orbit satellite constellation, the satellite is oriented toward the edge of the Earth from an orbital altitude of about 1000 km. Based on the basic design concept of a satellite constellation that monitors flying objects in the mid-latitude region near 30 degrees latitude against a cosmic background, the orbital inclination angle is inclined by about 20 degrees.

[0046] FIG. 8 is a diagram showing a satellite constellation in equatorial orbit according to this embodiment. FIG. 9 is a diagram showing a satellite constellation in an equatorial orbit according to this embodiment, which is inclined at an orbital inclination angle of 20 degrees. FIG. 10 is a diagram showing the concept of stereoscopic viewing in a satellite constellation in an equatorial orbit with an orbital inclination angle of 20 degrees according to this embodiment.

[0047] Surveillance aimed at the edge of the Earth is also called limb surveillance. Since limb surveillance can monitor the vehicle against the backdrop of space, it is possible to monitor the vehicle's body, which has risen in temperature after the end of the burn, without being affected by errors using infrared monitoring equipment. Satellites in equatorial orbit can constantly monitor the mid-latitude rim by flying in a formation of six or more satellites, even though the Earth's rotation speed and the satellite's orbital speed are different. When a satellite constellation in an equatorial orbit is inclined at an orbital inclination angle of 20 degrees, the latitudinal range for limb monitoring changes. The range that each satellite can monitor is a donut-shaped area as shown in Figures 9 and 10. Therefore, the satellite can monitor the mid-latitudes with line-of-sight vector components not only in the latitude direction but also in the longitude direction.

[0048] FIG. 11 is a diagram showing how flying object tracking system 500 according to this embodiment derives flying position coordinates based on the principle of spatial triangulation.

[0049] The flying object tracking system 500 according to the present embodiment adopts an orbit with an orbit altitude of 900 km or more and 2000 km or less and an orbit inclination angle of 20±10 degrees. If the flying object tracking system 500 tracks a flying object 600 flying at a mid-latitude of, for example, about 30 degrees north, it is possible to simultaneously monitor the flying object 600 with a plurality of line-of-sight vectors with large relative angles between the line-of-sight vectors. Therefore, there is an effect that the flying position coordinates of the flying object 600 can be derived with high accuracy by the principle of spatial triangulation.

[0050] Spatial triangulation is a method of deriving the position coordinates of an unknown point by measuring the solid angle of a line-of-sight vector directed from three points with known coordinates to a point with unknown coordinates. When using an infrared monitoring device, the solid angle of the line-of-sight vector is calculated from the line-of-sight vector of the infrared monitoring device and the flying object position included in the acquired data, and the flying object position coordinates are derived. For example, if the flight position of a satellite is known in the Earth-fixed coordinate system WGS84 used in the Global Positioning System (GPS) or the Quasi-Zenith Positioning Satellite System, the flight position of the flying object can be derived as WGS84 position coordinates.

[0051] Increasing the number of satellites to 100 or more increases the number of satellites that can simultaneously track a specific flying object, which has the effect of increasing the probability of successful countermeasures and the effect of increasing the number of flying objects that can be simultaneously tracked. Therefore, it goes without saying that the number of satellites may be 100 or more. In addition, the effect of setting the orbital inclination angle is to expand the latitude band in which limb monitoring can be performed, which has the effect of expanding the monitoring range of the launch point from which the projectile is launched.

[0052] The launch detection information of the flying object may be acquired by the satellite itself. Also, the launch detection information of the flying object may be used as a trigger to track the flying object using a flying object tracking system. When the launch is detected by the satellite itself, if an infrared monitoring device pointing to the earth's surface is equipped, it is possible to detect the high-temperature spray called a plume that occurs when the flying object is launched. However, there is a problem that the number of satellites required increases in order to comprehensively detect the launch of flying objects launched from the mid-latitude zone. Because high-temperature spray spreads over a wide area, launch detection is possible using infrared monitoring from geostationary orbit satellites, so it is reasonable to obtain missile launch detection information from a geostationary satellite and use it as a trigger for tracking by a missile tracking system.

[0053] <Configuration Example 1 of the flying object tracking system 500 according to the present embodiment> FIG. 12 is a diagram showing a first configuration example of a flying object tracking system 500 according to the present embodiment.

[0054] In the configuration example 1 of the flying object tracking system 500, six monitoring satellites 120 fly on each of four orbital planes of the satellite constellation 20. The configuration example 1 of the flying object tracking system 500 is composed of a total of 24 monitoring satellites 120.

[0055] FIG. 5 is a diagram showing the configuration example 1 of the flying object tracking system 500 as seen from above the equator. The right diagram in FIG. 12 is a diagram of the configuration example 1 of the flying object tracking system 500 as viewed from the North Pole. The left diagram in FIG. 12 is a diagram showing the satellite flight positions in each orbital plane in a diagram of the configuration example 1 of the flying object tracking system 500 as viewed from the North Pole.

[0056] <Configuration Example 2 of the Flying Object Tracking System 500 According to the Present Embodiment> FIG. 13 is a diagram showing the configuration example 2 of the flying object tracking system 500 according to the present embodiment as viewed from the North Pole. FIG. 14 is a diagram showing the configuration example 2 of the flying object tracking system 500 according to the present embodiment as viewed from above the equator.

[0057] In the configuration example 2 of the flying object tracking system 500, six monitoring satellites 120 fly on each of six orbital planes of the satellite constellation 20. The configuration example 2 of the flying object tracking system 500 is composed of a total of 36 monitoring satellites 120.

[0058] The right diagram in FIG. 13 is a diagram of the configuration example 2 of the flying object tracking system 500 as viewed from the North Pole. The left diagram of FIG. 13 is a diagram showing the satellite flight positions in each orbital plane in a diagram of the configuration example 2 of the flying object tracking system 500 as viewed from the North Pole. FIG. 14 is a diagram showing the configuration example 2 of the flying object tracking system 500 as seen from above the equator.

[0059] <Configuration Example 3 of the flying object tracking system 500 according to the present embodiment> FIG. 15 is a diagram showing a third configuration example of a flying object tracking system 500 according to the present embodiment.

[0060] In the third configuration example of the flying object tracking system 500, the monitoring satellites 120 constituting each of the multiple orbital planes included in the satellite constellation 20 communicate with satellites flying in front and behind them to form a circular communication network 700.

[0061] If the orbital altitude is 1000 km or more, six or more satellites can fly in equal phase in the same orbital plane and communicate with the satellites in front and behind, forming a circular communication network 700. Satellite information on the same orbital plane can be shared by the ring communication network 700. Therefore, if any of the monitoring satellites 120 in the ring communication network 700 can communicate with the ground system 130 or a satellite not on the same orbit, it can transmit information on behalf of all satellites on the same orbital plane. In the flying object tracking system 500, in order to transmit acquired flying object information quickly, it is rational to transmit the satellite information to the ground system 130 or another satellite via the ring communication network 700.

[0062] <Configuration Example 4 of the Flying Object Tracking System 500 According to the Present Embodiment> FIG. 16 is a diagram showing a fourth configuration example of a flying object tracking system 500 according to the present embodiment.

[0063] In the fourth configuration example of the flying object tracking system 500, satellite information is transmitted between monitoring satellites 120 passing near an intersection between a plurality of orbital planes having different longitudinal components of normal vectors.

[0064] Two orbital planes that fly at the same orbital altitude and have different longitudinal components of their normal vectors form two orbital plane intersections. Therefore, by having satellites that pass near the orbital plane intersections communicate with each other on behalf of the satellite information held by the circular communication network, it is possible to share the satellite information between the two orbital planes. All orbital planes that make up the satellite constellation form communications between the two orbital planes with one of the intersections with the other orbital planes. This has the effect of allowing all satellites that make up the satellite constellation to share satellite information, even if they do not necessarily communicate comprehensively at all intersections. In addition, in the vicinity of the intersection, the relative distance is limited, so that the communication device can be made compact and lightweight. In addition, in the case of radio wave communication, communication can be made using a fixed antenna.

[0065] <Configuration Example 5 of the Flying Object Tracking System 500 According to the Present Embodiment> FIG. 17 is a diagram showing a fifth configuration example of a flying object tracking system 500 according to the present embodiment.

[0066] In the configuration example 5 of the flying object tracking system 500, satellite information is transmitted between satellites passing near the equator between orbital planes in which the longitude components of normal vectors are opposed. The longitude components of normal vectors are opposed to each other means that the longitude components of normal vectors face each other.

[0067] In a combination of orbital planes in which the longitudinal components of the normal vectors are opposed to each other, two intersections of the orbital planes are formed above the equator. Therefore, by having satellites passing near the equator communicate with each other on behalf of the satellite information held by the circular communication network 700, it is possible to share the satellite information between the two orbital planes. In the vicinity of the intersection, the relative distance is limited, so that the communication device can be made compact and lightweight. In addition, in the case of radio wave communication, communication can be made using a fixed antenna. In addition, in the combination of orbital planes where the longitudinal components of the normal vectors are opposed to each other, the satellite's direction of travel and attitude when passing near the equator are known in advance. This has the effect of making it possible to communicate using fixed antennas in the case of radio communication, and easy alignment of the optical axis in the case of optical communication, which has the effect of reducing costs.

[0068] FIG. 18 is a diagram showing an example of transmission of satellite information in the flying object tracking system 500 according to this embodiment. (1) The monitoring satellite 120 acquires satellite information such as information on flying objects or launch detection information. (2) Transmission of satellite information via intra-orbital communications (3) Transmission of satellite information via inter-orbit communications (4) Transmission of satellite information by intra-orbital communications in a different orbital plane than that of (2). (5) Transmitting satellite information to ground systems via communication with the ground

[0069] ***Additional explanation of the effects of this embodiment*** In this embodiment, in order to solve the problem of low latitudinal accuracy in deriving aircraft position coordinates in a RIM monitoring system using an equatorial orbit, we have proposed an aircraft tracking system that can perform spatial triangulation with a minimum number of aircraft (24 or more) on an inclined orbit of about 20 degrees. The flying object tracking system according to this embodiment can achieve the following effects. The normal vector of the orbital plane of the RIM Surveillance System's satellite constellation in an equatorial orbit is tilted by about 20 degrees, and the amount of latitudinal movement is used to ensure the solid angle of the line of sight vector in spatial triangulation. With a limited number of satellites, such as a total of 24 satellites (4 orbital planes, 6 in each plane) or 36 satellites (6 orbital planes, 6 in each plane), a system for tracking flying objects from west to east in the mid-latitudes will be realized. By communicating with satellites in front and behind the satellite in the same orbital plane to form a circular communications network, surveillance and communications are integrated, simplifying communications operations. Communication between orbital planes with different normal vectors can be achieved by near-field communication when passing near an orbital intersection, enabling communication using omnidirectional or fixed antennas. - The circular communication network and near-junction communication allow for quick and easy transmission of missile information.

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

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

[0072] 20 satellite constellation, 120 surveillance satellite, 121 communication device, 122 surveillance device, 123 propulsion device, 124 attitude control device, 125 satellite control device, 126 power supply device, 130 ground system, 132 satellite control device, 500 flying object tracking system, 600 flying object, 700 circular communication network, 910 processor, 921 memory, 922 auxiliary storage device, 930 input interface, 940 output interface, 950 communication device.

Claims

1. The system is made up of a constellation of satellites each of which is equipped with an infrared monitoring device pointing toward the Earth's periphery and flies in an inclined orbit; A flying object called a Hypersonic Glide Vehicle (HGV) changes its flight path by intermittently jetting during flight. After the jet stops jetting, the temperature of the flying object's body is monitored and detected with high resolution and high sensitivity infrared monitoring from a closer distance than a geostationary satellite. A flying object tracking system that monitors and tracks flying objects using flying object launch detection information that detects the launch of a flying object as a trigger, The satellite constellation has an orbital altitude of 900 km or more and an orbital inclination angle of 20±10 degrees, and six or more satellites fly on each of four or more orbital planes whose normal vectors are evenly distributed in the longitude direction; A missile tracking system that uses stereoscopic vision to improve the accuracy of deriving flight position coordinates compared to equatorial orbits in a constellation of several dozen low-orbit satellites, and performs constant monitoring to immediately transmit information to response assets upon detection of the launch of a missile.

2. 2. The airborne object tracking system according to claim 1, wherein the satellite constellation is composed of 24 satellites in total, with 6 satellites flying in each of 4 orbital planes.

3. 2. The airborne object tracking system according to claim 1, wherein the satellite constellation is composed of six orbital planes, each of which has six satellites, for a total of 36 satellites.

4. 2. The flying object tracking system according to claim 1, wherein satellites constituting each of a plurality of orbital planes included in the satellite constellation communicate with satellites flying in front and behind, forming a circular communication network.

5. 5. The flying object tracking system according to claim 4, wherein among the plurality of orbital planes, in orbital planes having different longitudinal components of normal vectors, satellite information is transmitted between satellites passing near an intersection between the orbital planes.

6. 5. The flying object tracking system according to claim 4, wherein satellite information is transmitted between satellites passing near the equator in orbital planes in which longitudinal components of normal vectors of the plurality of orbital planes are opposed to each other.

7. A satellite constellation in an inclined orbit, each satellite being equipped with an infrared monitoring device pointing toward the edge of the Earth, The Hypersonic Glide Vehicle (HGV), which changes its flight path by intermittently firing during flight, detects the temperature of the main body of the vehicle after it stops firing using high-resolution and high-sensitivity infrared monitoring from a much closer distance than a geostationary satellite. A flying object tracking system that monitors and tracks flying objects using flying object launch detection information that detects the launch of a flying object as a trigger, The satellite constellation has an orbital altitude of 900 km or more and an orbital inclination angle of 20±10 degrees, and six or more satellites fly on each of four or more orbital planes whose normal vectors are evenly distributed in the longitude direction; A satellite constellation includes a plurality of orbital planes, each of which is composed of a satellite, and the satellites constellation includes a satellite that is flying in front of or behind the ... form a circular communication network. A flying object tracking system that transmits satellite information between satellites that pass near an intersection between the orbital planes having different longitudinal components of normal vectors among the plurality of orbital planes.

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