JP2023058047A - Missile tracking system - Google Patents

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

The present disclosure relates to technology for tracking the flight trajectory of a flying object.

There is a projectile countermeasure system that assumes that the projectile will fly ballistically.
The flying object countermeasure system uses an infrared observation device mounted on a geostationary orbit satellite to detect the plume at the time of launch, predicts the landing position based on movement information in the early stages of flight, and responds with the countermeasure system. When launched, extremely hot gas spreads over a wide area. Therefore, it is possible to detect flying objects even when monitoring from a geostationary orbit.

Recently, however, a flying object called a Hypersonic Glide Vehicle (HGV) has appeared and poses a new threat. This flying object intermittently jets during flight to change its flight path.
In order to track a flying object that has stopped jetting, it is necessary to detect the temperature of the main body of the flying object. Therefore, high-resolution and high-sensitivity infrared monitoring is required, which cannot be handled by conventional monitoring using geostationary satellites.

Therefore, research has begun on a system for monitoring flying objects from much shorter distances than geostationary orbit using a low-orbit satellite constellation.
And there is a long-awaited mechanism for constant monitoring by a low-orbit satellite constellation and transmission of information to response assets immediately after the launch of a flying object is detected.
A low earth orbit satellite constellation is a satellite constellation made up of low earth orbit satellites.
A constellation of low earth orbit satellites is one or more low earth orbit satellites.
A low earth orbit satellite is a satellite that flies in a low earth orbit, such as LEO.
LEO is an abbreviation for Low Earth Orbit.

Patent Literature 1 discloses a surveillance satellite orbiting in a low earth orbit to comprehensively monitor an area at a specific latitude within the global surface of the earth.

Japanese Patent No. 4946398

Concepts for a launch detection and tracking system based on a constellation of low-Earth orbit satellites in the hundreds are under consideration, but cost scale is a challenge. Therefore, a low-orbit satellite constellation with a small number of satellites is awaited, and there is a concept of a flying object tracking system that monitors the rim from an equatorial orbit using a low-orbit satellite constellation with several dozen satellites.
However, in the equatorial orbit, there is a problem that the accuracy in the latitudinal direction is poor in deriving the position coordinates of the flying object by stereoscopic vision.

An object of the present disclosure is to improve the derivation accuracy of flight position coordinates by stereoscopic vision in a low-orbit satellite constellation of several tens of satellites.

A flying object tracking system according to the present disclosure comprises a satellite constellation in which each satellite is equipped with an infrared monitoring device that points to the periphery of the earth, and that is configured by a satellite constellation that flies in an inclined orbit. A flying object tracking system that monitors and tracks a flying object using as a trigger,
The satellite constellation has an orbital altitude of 900 km or more and 2000 km or less, an orbital inclination of 20±10 degrees, and six or more satellites on each of four or more orbital planes with normal vectors evenly distributed in the longitudinal direction. Satellites fly.

According to the flying object tracking system according to the present disclosure, it is possible to realize flying object tracking in a mid-latitude band with several tens of satellites, and to improve the accuracy of deriving the flight position coordinates by stereoscopic viewing of multiple satellites. has the effect of

1 is a diagram showing a configuration example of a flying object tracking system according to Embodiment 1; FIG. 2 is a diagram showing a configuration example of a monitoring satellite according to Embodiment 1; FIG. 2 is a diagram showing a hardware configuration example of a ground system according to Embodiment 1; FIG. 4 is a diagram showing an example of functions of the flying object tracking system according to the first embodiment; FIG. 1 is a diagram showing a configuration example of a flying object tracking system according to Embodiment 1; FIG. FIG. 4 is a diagram showing the concept of stereoscopic viewing by an equatorial orbiting satellite for comparison with the flying object tracking system according to the first embodiment; FIG. 4 is a diagram showing the concept of stereoscopic viewing by a satellite in an inclined orbit or a polar orbit for comparison with the flying object tracking system according to the first embodiment; FIG. 2 is a diagram showing a satellite constellation in an equatorial orbit according to Embodiment 1; FIG. 2 is a diagram showing a satellite constellation in an equatorial orbit tilted at an orbital inclination angle of 20 degrees according to the first embodiment; FIG. 4 is a diagram showing the concept of stereoscopic vision in a satellite constellation in which the satellite constellation in the equatorial orbit according to the first embodiment is tilted at an orbital inclination angle of 20 degrees; 4 is a diagram showing derivation of flight position coordinates based on the principle of spatial triangulation in the flying object tracking system according to the first embodiment; FIG. 1 is a diagram showing configuration example 1 of a flying object tracking system according to Embodiment 1; FIG. FIG. 2 is a view of Configuration Example 2 of the flying object tracking system according to Embodiment 1 as viewed from the North Pole; FIG. 2 is a view of Configuration Example 2 of the flying object tracking system according to Embodiment 1 as seen from above the equator; FIG. 10 is a diagram showing a configuration example 3 of the flying object tracking system according to the first embodiment; FIG. 10 is a diagram showing a configuration example 4 of the flying object tracking system according to the first embodiment; FIG. 10 is a diagram showing a configuration example 5 of the flying object tracking system according to Embodiment 1; 4 is a diagram showing an example of satellite information transmission in the flying object tracking system according to the first embodiment; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings. In each figure, the same reference numerals are given to the same or corresponding parts. In the description of the embodiments, the description of the same or corresponding parts will be omitted or simplified as appropriate. In addition, in the following drawings, the size relationship of each component may differ from the actual one. In addition, in the description of the embodiments, directions or positions such as "top", "bottom", "left", "right", "front", "back", "front", and "back" are indicated. There is These notations are provided as such for convenience of explanation only and are not intended to limit the arrangement and orientation of structures such as devices, instruments or components.

Embodiment 1.
*** Configuration description ***
FIG. 1 is a diagram showing a configuration example of a flying object tracking system 500 according to this embodiment.

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.

Projectile tracking system 500 includes satellite constellation 20 and ground system 130 .
Satellite constellation 20 has a plurality of surveillance satellites 120 .
Monitoring satellite 120 is an artificial satellite for monitoring flying object 600 . Monitoring satellites 120 may also be simply referred to as satellites.

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

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

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.
Monitor 122 is an example of an infrared monitor pointing at the Earth's limbs.
The monitoring satellite 120 has a pointing function for directing the line of sight to the flying object 600 .

The monitoring data is data corresponding to an image of the flying object 600 and indicates the position of the flying object 600 in the field of view (monitoring range) of the monitoring device 122 .
The monitoring data may include time information, position information, line-of-sight information, field-of-view information, and the like. The time information indicates the time when monitoring was performed (monitoring time). The position information indicates 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 .

The propulsion device 123 is a device that gives propulsion to the surveillance satellite 120 and changes the speed of the surveillance satellite 120 . Specifically, the propulsion device 123 is an electric propulsion machine. For example, propulsion device 123 is an ion engine or a Hall thruster.

The attitude control device 124 is a device for controlling attitude elements such as the attitude of the surveillance satellite 120 and the angular velocity of the surveillance satellite 120 .
Attitude control device 124 changes each attitude element in a desired direction. Alternatively, attitude controller 124 maintains each attitude element in the desired orientation. The attitude control device 124 includes an attitude sensor, an actuator, and a controller. Attitude sensors include gyroscopes, earth sensors, sun sensors, star trackers, thrusters and magnetic sensors. Actuators include attitude control thrusters, momentum wheels, reaction wheels and control moment gyros. The controller controls the actuators according to measurement data from the attitude sensor or various commands from the ground system 130 .
The attitude control device 124 can be used as a device for changing the viewing direction of the monitoring device 122 (viewing direction changing device). The viewing direction of the monitoring device 122 corresponds to the viewing direction of the monitoring device 122 . A range (field of view) centered on the line-of-sight direction of the monitoring device 122 is a monitoring range.

The satellite control device 125 is a computer that controls each device of the surveillance satellite 120 and has a processing circuit. For example, the satellite controller 125 controls each device according to various commands sent from the ground system 130 .

The power supply device 126 includes a solar battery, a battery, a power control device, and the like, and supplies power to each device of the surveillance satellite 120 .

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

Processing circuits provided in each of the satellite control device 132 and the satellite control device 125 will be described.
The processing circuitry may be dedicated hardware or a processor executing a program stored in memory.
In the processing circuit, some functions may be implemented in dedicated hardware and the remaining functions may be implemented in software or firmware. That is, processing circuitry can be implemented in hardware, software, firmware, or a combination thereof.
Dedicated hardware may be, for example, single circuits, multiple circuits, programmed processors, parallel programmed processors, ASICs, FPGAs, or combinations thereof.
ASIC is an abbreviation for Application Specific Integrated Circuit.
FPGA is an abbreviation for Field Programmable Gate Array.

The adjustment of satellite altitude and orbital inclination will be explained.
The relative angle of the normal to the orbital plane of the surveillance satellite 120 as viewed from the north pole side is established 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 laps per day, the satellite constellation 20 can be operated while maintaining the relative angle between the orbital planes.
Satellite controller 132 generates commands for controlling the altitude of each surveillance satellite 120 . The satellite control device 132 also generates commands for controlling the orbital inclination of each surveillance satellite 120 . The satellite control device 132 then transmits these commands to each monitoring satellite 120 .
In each surveillance satellite 120, the satellite controller 125 adjusts the satellite altitude and orbital inclination, respectively, according to these commands. Specifically, satellite controller 125 controls propulsion device 123 according to these commands. The satellite altitude and orbital inclination can be adjusted by the propulsion unit 123 changing the satellite velocity.
As the flight speed of surveillance satellite 120 increases, the altitude of surveillance satellite 120 increases. As the altitude of the surveillance satellite 120 increases, the ground speed of the surveillance satellite 120 decreases.
As the flight speed of surveillance satellite 120 slows down, the altitude of surveillance satellite 120 decreases. When the altitude of the surveillance satellite 120 descends, the ground speed of the surveillance satellite 120 increases.
If the propulsion device 123 generates thrust in a direction perpendicular to the orbital plane at a point (an equinox) where the surveillance satellite 120 crosses the sky above the equator, the orbital inclination angle can be finely adjusted effectively.

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

Processor 910 is a device that executes a program that implements the functions of ground system 130 .
The processor 910 is an IC (Integrated Circuit) that performs arithmetic processing. Specific examples of the processor 910 are a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and a GPU (Graphics Processing Unit).

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

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

Communication device 950 has a receiver and a transmitter. The communication device 950 is specifically a communication chip or a NIC (Network Interface Card).

A program that implements the functions of ground system 130 is loaded into processor 910 and executed by processor 910 . The memory 921 stores not only programs but also an OS (Operating System). The processor 910 executes programs while executing the OS. The program and OS may be stored in the auxiliary storage device 922 . The programs and OS stored in the auxiliary storage device 922 are loaded into the memory 921 and executed by the processor 910 . Part or all of the program that implements the functions of the ground system 130 may be incorporated in the OS.

Ground system 130 may include multiple processors in place of processor 910 . These multiple processors share program execution. Each processor, like processor 910, is a device that executes a program.

The data, information, signal values and variable values used, processed or output by the programs may be stored in memory 921 , secondary storage 922 , registers or cache memory within processor 910 .

The "part" of each part of the ground system 130 may be read as "processing", "procedure", "means", "step", "circuitry" or "process". Also, the “part” of each part of the ground system 130 may be read as “program”, “program product” or “computer-readable recording medium recording the program”. "Process", "procedure", "means", "step", "circuitry" or "process" can be read interchangeably.

*** Function overview of the flying object tracking system 500 ***
FIG. 4 is a diagram showing an example of functions of the flying object tracking system 500 according to this embodiment.

A flying object tracking system 500 is composed of a satellite constellation 20 that flies in an inclined orbit. In satellite constellation 20, each satellite has an infrared monitor pointing at the earth's periphery. The flying object tracking system 500 monitors and tracks the flying object 600 triggered by the flying object launch detection information. The flying object launch detection information is information that the launch of the flying object 600 has been detected.

When the flying object 600 is launched, the high-temperature atmosphere diffuses, so monitoring can be facilitated. However, the body of the flying object in the post-boost phase has a small solid angle that can be seen from the surveillance satellite 120, and the temperature rise is not as remarkable as that of the plume. Therefore, if the background land information is mixed with the flying object information, there is a concern that the flying object cannot be identified. The post-boost phase is the phase after injection has ceased.
Therefore, by using a monitoring method called rim observation, which points toward the earth's periphery, the body of the flying object whose temperature has risen is monitored against the background of deep space.
As a result, the flying object can be monitored without the flying object information being buried in noise.

The position coordinates (coordinate values) of the flying object 600 are derived according to 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 converge based on the azimuth (line-of-sight direction) of the line-of-sight vectors of the respective monitoring satellites 120 .
As the azimuth angle of the line-of-sight vector seen from the flying object 600 is dispersed, the position measurement accuracy is improved.

The satellite control device functions as a flight path prediction device that integrates flying object information indicating high-temperature objects detected by a plurality of surveillance satellites and analyzes changes in time-series positional information. As a result, the flying object can be tracked and the flight path can be predicted.
Even if the flying object intermittently re-injects mid-flight and changes its traveling direction, the flight path prediction device tracks the traveling direction and continuously acquires time-series information, so that it is possible to take measures against the flying object. It becomes possible.

***Description of the flying object tracking system 500 according to the present embodiment***
FIG. 5 is a diagram showing a configuration example of a flying object tracking system 500 according to this embodiment.
A flying object tracking system 500 according to this embodiment is composed of a satellite constellation 20 . Each surveillance satellite 120 of satellite constellation 20 comprises an infrared surveillance device pointing toward the earth's periphery. The satellite constellation 20 flies in an inclined orbit.
The flying object tracking system 500 monitors and tracks the flying object 600 by using the flying object launch detection information that detects the launch of the flying object 600 as a trigger.
The flying object tracking system 500 comprises a satellite constellation 20 in which six or more satellites fly on four or more orbital planes.
The orbit altitude of each orbit is 900 km or more and 2000 km or less.
The orbit inclination angle of each orbit is 20±10 degrees.
Also, the normal vector of each trajectory is evenly distributed in the longitudinal direction.

FIG. 6 is a diagram showing the concept of stereoscopic viewing by a satellite in an equatorial orbit for comparison with the flying object tracking system 500 according to the present embodiment.

It is no longer possible to deal with flying objects only by launch detection from geostationary orbit. Hundreds of satellites are said to be necessary to maintain a constant global surveillance system, and there is a risk that the cost of the system will be extremely high.
On the other hand, a satellite constellation has been proposed that achieves mid-latitude tracking of mid-latitude flying objects with a small number of satellites, about ten, by forming a satellite constellation in a string over the equator.
However, in satellite constellations above the equator, the relative angle of the line-of-sight vector for acquiring stereo pair images is small when deriving flight position coordinates from stereo pair images obtained by simultaneously monitoring flying objects with multiple aircraft. Therefore, there is a problem that the measurement error in the latitudinal direction increases.

FIG. 7 is a diagram showing the concept of stereoscopic viewing by a satellite in an inclined orbit or a polar orbit for comparison with the flying object tracking system 500 according to the present embodiment.
On the other hand, satellite constellations with inclined orbits or polar orbits can acquire stereo pair images with large relative angles of line-of-sight vectors. Therefore, there is an effect that highly accurate flying object position coordinates can be derived by the principle of spatial triangulation. However, in order to construct a monitoring system using a satellite constellation in an inclined orbit or a polar orbit, there is a problem that a large number of satellites of 100 or more are required.

Therefore, this embodiment provides a flying object tracking system 500 that tracks a flying object flying in a mid-latitude band with a satellite constellation of 100 or less.
In the present embodiment, the advantage of the satellite constellation in the equatorial orbit is utilized to direct the earth's periphery from an orbital altitude of about 1000 km. As a result, the orbital inclination angle is inclined by about 20 degrees based on the basic design concept of a satellite constellation that monitors a flying object flying over a mid-latitude band around 30 degrees latitude in the space background.

FIG. 8 is a diagram showing a satellite constellation in equatorial orbit according to the present embodiment.
FIG. 9 is a diagram showing a satellite constellation in which the satellite constellation in the equatorial orbit according to the present embodiment is tilted at an orbit inclination angle of 20 degrees.
FIG. 10 is a diagram showing the concept of stereoscopic vision in a satellite constellation in which the satellite constellation in the equatorial orbit according to the present embodiment is inclined at an orbital inclination angle of 20 degrees.

Surveillance directed at the earth's periphery is also called rim surveillance. Since the rim monitoring can monitor the flying object against the background of space, the infrared monitoring device can monitor the flying object whose temperature has risen after the end of injection without being buried in errors.
With satellites in equatorial orbit, even if the rotation speed of the earth and the satellite's orbital speed are different, the rim can be constantly monitored by six or more satellites flying in a constellation.
If the satellite constellation in the equatorial orbit is tilted at an orbital inclination angle of 20 degrees, the latitudinal band range for rim monitoring will vary. The range in which individual satellites can monitor the rim is a doughnut-shaped area as shown in FIGS. Therefore, the satellite can monitor the mid-latitude band with line-of-sight vector components not only in the latitudinal direction but also in the longitudinal direction.

FIG. 11 is a diagram showing derivation of flight position coordinates based on the principle of spatial triangulation in the flying object tracking system 500 according to this embodiment.

The flying object tracking system 500 according to the present embodiment employs a trajectory with a trajectory 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 the flying object 600 flying at a mid-latitude of about 30 degrees north latitude, for example, the flying object 600 can be simultaneously monitored using a plurality of line-of-sight vectors with large relative angles. Therefore, there is an effect that the flight position coordinates of the flying object 600 can be derived with high accuracy by the principle of spatial triangulation.

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 pointing from three points with known position coordinates to a point with unknown position coordinates. When an infrared monitoring device is used, the solid angle of the line-of-sight vector is calculated from the line-of-sight vector of the infrared monitoring device and the position of the flying object included in the acquired data, and the position coordinates of the flying object are derived.
For example, if the flight position of the satellite is known in the earth-fixed coordinate system WGS84 adopted by GPS (Global Positioning System) or the quasi-zenith positioning satellite system, the flight position of the flying object can be derived as the WGS84 position coordinates.

By increasing the number of satellites to 100 or more, the number of satellites that can simultaneously track unique flying objects increases, which has the effect of increasing the probability of successful countermeasures and increasing the number of simultaneously trackable flying objects. Therefore, it goes without saying that the number of satellites may be 100 or more.
In addition, the effect of adding the orbital inclination angle widens the monitorable latitude band in which rim monitoring is possible.

The launch detection information of the flying object may be acquired by the own satellite. In addition, the flying object tracking system may track the flying object using the flying object launch detection information as a trigger. In the case of launch detection with its own satellite, it is possible to detect a high-temperature spray called a plume when a flying object is launched by equipping it with an infrared monitoring device that points to the ground surface. However, there is a problem that the number of satellites required to comprehensively detect the launch of a flying object launched from the mid-latitude band increases.
Since high-temperature spray spreads over a wide area, launch detection can be infrared-monitored even with a geostationary orbit satellite. be.

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

In configuration example 1 of the flying object tracking system 500, six surveillance satellites 120 fly on four orbital planes of the satellite constellation 20, respectively. Configuration example 1 of the flying object tracking system 500 is composed of a total of 24 monitoring satellites 120 .

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

<Configuration example 2 of flying object tracking system 500 according to the present embodiment>
FIG. 13 is a diagram of configuration example 2 of the flying object tracking system 500 according to the present embodiment, viewed from the North Pole.
FIG. 14 is a diagram of configuration example 2 of the flying object tracking system 500 according to the present embodiment as viewed from above the equator.

In configuration example 2 of the flying object tracking system 500, six surveillance satellites 120 fly on six orbital planes of the satellite constellation 20, respectively. Configuration example 2 of the flying object tracking system 500 is composed of a total of 36 surveillance satellites 120 .

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

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

In configuration example 3 of the flying object tracking system 500, the monitoring satellites 120 forming each orbital plane of a plurality of orbital planes included in the satellite constellation 20 communicate with satellites flying in front and behind to form an annular communication network 700. do.

If the orbital altitude is 1000 km or more, six or more satellites fly in the same orbital plane with equal phases, and by communicating with preceding and succeeding satellites, an annular communication network 700 can be formed.
Satellite information in the same orbital plane can be shared by the annular communication network 700 . Therefore, if any of the monitoring satellites 120 in the toroidal communication network 700 can communicate with the ground system 130 or satellites that are not on the same orbit, it will be possible to transmit information on behalf of all satellites on the same orbital plane. Become.
In the flying object tracking system 500, in order to quickly transmit the obtained flying object information, it is rational to transmit the satellite information to the ground system 130 or another satellite via the annular communication network 700. FIG.

<Configuration example 4 of flying object tracking system 500 according to the present embodiment>
FIG. 16 is a diagram showing configuration example 4 of the flying object tracking system 500 according to the present embodiment.

In the configuration example 4 of the flying object tracking system 500, satellite information is transmitted between the surveillance satellites 120 passing near the intersection of the orbital planes in which the longitudinal component of the normal vector differs among the plurality of orbital planes. .

Two points of intersection of the orbital planes are formed between two orbital planes that fly at the same orbital altitude and have different longitudinal components of normal vectors. Therefore, the satellite information held by the annular communication network is communicated by the satellites passing near the intersection of the orbital planes on behalf of each other, so that the satellite information can be shared between the two orbital planes. All orbital planes that make up the satellite constellation form a communication between the two orbital planes with any of their intersections with other orbital planes. As a result, there is an effect that all satellites forming the satellite constellation can share satellite information even if communication is not exhaustively performed at all intersections.
Moreover, since the relative distance is limited in the vicinity of the intersection, there is an effect that the communication device can be made compact and lightweight. In addition, there is an effect that radio communication can be performed using a fixed antenna.

<Configuration example 5 of flying object tracking system 500 according to the present embodiment>
FIG. 17 is a diagram showing configuration example 5 of the flying object tracking system 500 according to the present embodiment.

In 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 longitudinal component of the normal vector is opposed. That the longitudinal direction components of the normal vector face each other means that the longitudinal direction components of the normal vector face each other.

In a combination of orbital planes having opposite longitudinal components of normal vectors, two points of intersection of the orbital planes are formed above the equator. Therefore, the satellite information held by the ring-shaped communication network 700 is communicated by the satellites passing near the equator on behalf of each other, so that there is an effect that the satellite information can be shared in two orbital planes.
Since the relative distance is limited in the vicinity of the intersection, there is an effect that the communication device can be made compact and lightweight. In addition, there is an effect that radio communication can be performed using a fixed antenna.
Further, in a combination of orbital planes in which the longitudinal component of the normal vector is opposite, the advancing direction and attitude of the satellite when passing near the equator are known in advance. Therefore, radio communication can be performed using a fixed antenna, and optical communication can be easily aligned with the optical axis, resulting in cost reduction.

FIG. 18 is a diagram showing an example of satellite information transmission in the flying object tracking system 500 according to this embodiment.
(1) Monitoring satellite 120 acquires satellite information such as flying object information or launch detection information (2) Transmission of satellite information by inter-orbit communication (3) Transmission of satellite information by inter-orbit communication (4) (2) Transmission of satellite information by communication between the same orbital plane in a different orbital plane (5) Transmission of satellite information to the ground system through communication with the ground

*** Supplementary explanation of the effects of the present embodiment ***
In this embodiment, in order to solve the problem of low latitudinal accuracy in deriving the position coordinates of a flying object in a rim monitoring system based on an equatorial orbit, a space triangulation system is proposed with a minimum number of aircraft (24 or more) in an inclined orbit of about 20 degrees. A surveyable projectile tracking system is proposed.
The flying object tracking system according to this embodiment can achieve the following effects.
・Incline the normal vector of the satellite constellation of the rim monitoring system in the equatorial orbit by about 20 degrees, and secure the solid angle of the line-of-sight vector in spatial triangulation using the amount of latitudinal movement.
・Limited number of satellites: 24 (4 orbital planes, 6 each orbital plane), 36 (6 orbital planes, 6 each orbital plane), flying from west to east in the middle latitude zone Implemented a flying object tracking system.
・Simplify communication operations by integrating monitoring and communication by forming an annular communication network by communicating with the preceding and following satellites in the same orbital plane.
・Communication between orbital planes with different normal vectors is achieved by close communication when passing near the intersection of the orbits, enabling communication with omnidirectional or fixed antennas.
・Flying object information can be transmitted quickly and easily through a ring-shaped communication network and near-intersection communication.

In the first embodiment described above, the configurations of each system and each device such as the flying object tracking system and the surveillance satellite may not be the configurations of the above-described embodiments. The configuration of each system and each device may be any configuration as long as the functions described in the above embodiments can be realized.
Further, it is also possible to combine a plurality of parts or examples of the first embodiment. Alternatively, one portion or example of this embodiment may be implemented. In addition, these embodiments may be implemented in any combination as a whole or in part.
That is, in Embodiment 1, it is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component from each embodiment.

The above-described embodiments are essentially preferable examples, and are not intended to limit the scope of the present disclosure, the scope of application of the present disclosure, and the range of applications of the present disclosure. Various modifications can be made to the above-described embodiments as required.

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 (6)

Each satellite is equipped with an infrared monitoring device that points to the earth's periphery, and consists of a satellite constellation that flies in an inclined orbit. A projectile tracking system that
The satellite constellation has an orbital altitude of 900 km or more and 2000 km or less, an orbital inclination of 20±10 degrees, and six or more satellites on each of four or more orbital planes with normal vectors evenly distributed in the longitudinal direction. A flying object tracking system in which satellites fly. 2. The projectile tracking system of claim 1, wherein said satellite constellation comprises a total of 24 satellites, with 6 satellites in each of 4 orbital planes. 2. The projectile tracking system of claim 1, wherein said satellite constellation comprises 36 satellites in total, with 6 satellites in each of 6 orbital planes. 2. The flying object tracking system according to claim 1, wherein satellites forming each orbital plane of a plurality of orbital planes included in said satellite constellation communicate with satellites flying forward and backward to form an annular communication network. 5. The flying object tracking system according to claim 4, wherein, among the plurality of orbital planes, satellite information is transmitted between satellites passing near intersections of the orbital planes having different longitudinal components of normal vectors. 5. The flying object tracking system according to claim 4, wherein, among the plurality of orbital planes, satellite information is transmitted between satellites passing near the equator in orbital planes having opposite longitudinal components of normal vectors.

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