Space perspective method

Abstract

The present application relates to a space perspective method, comprising: S1, obtaining prior information of a space target; S2, deploying a perspective satellite system loaded with a cruising robot relative to the space target, wherein the cruising robot is loaded with a perspective load; S3, the cruising robot performs a space perspective task on the space target according to the prior information. The present application can realize high-precision and close-range internal structure perspective detection of a target in a space dimension.

Description

Technical Field

[0001] This invention relates to the fields of aerospace technology, satellite payload technology, and optical technology, and specifically to a space perspective method. Background Technology

[0002] Internal feature detection capabilities are essential for spacecraft equipment repair and maintenance. For example, frequent rendezvous and docking are required during spacecraft refueling and module replacement. Physical damage from impacts to the overall structure and components can easily lead to serious accidents. Therefore, regular assessments of structural cracks and internal deformations are necessary, requiring X-ray vision capabilities. Simultaneously, the aging of vulnerable components (such as gyro momentum wheels, optoelectronic components, and batteries) significantly impacts spacecraft lifespan. Since on-orbit component replacement is costly, X-ray vision is used to assess the internal structure of spacecraft to determine maintenance needs and predict component aging issues in advance. Furthermore, after space debris collisions, spacecraft are often damaged or pose various risks, necessitating health status assessments and maintenance. For damaged spacecraft, this involves inspecting the damage and evaluating repair solutions. In conclusion, there is an urgent need for an internal feature detection capability to detect the internal characteristics of spacecraft. Summary of the Invention

[0003] In view of this, the present invention aims to propose a spatial perspective method to solve the current problem of not being able to detect the internal structure of space targets.

[0004] To achieve the above-mentioned objectives of the present invention, the present invention adopts the following technical solution:

[0005] A spatial perspective method of the present invention includes:

[0006] S1: Obtain prior information about the spatial target and complete the initial intelligent planning for the perspective task;

[0007] S2, deploy the see-through satellite system carrying the patrol robot relative to the space target, wherein the patrol robot is equipped with a see-through payload;

[0008] S3, the patrol robot performs a spatial perspective task on the spatial target based on the prior information.

[0009] Furthermore, in S1:

[0010] The prior information refers to the target's internal structural information, including the payload subsystem, thermal control subsystem, propulsion subsystem, power supply subsystem, data management subsystem, satellite structure subsystem, attitude measurement and control subsystem, telemetry and control subsystem, and data transmission subsystem.

[0011] Furthermore, in S2:

[0012] The perspective satellite system also includes a satellite platform, on which the patrol robot is mounted, and on which a target acquisition device is also installed.

[0013] Furthermore, in S2:

[0014] The perspective payload includes a transmission payload, a backscattering payload, or a combination of transmission and backscattering payloads. The perspective payload includes perspective payloads on satellite platforms and perspective payloads on patrol robots. The target acquisition device includes a target acquisition camera, a lidar, and a binocular camera.

[0015] Furthermore, in step S2, the deployment of the perspective satellite system requires the satellite platform to complete the following operations:

[0016] The system consists of four phases: deployment to orbit, long-range guidance, short-range guidance, autonomous approach, hovering and observation, dispatching and receiving of patrol robots, and standby flight.

[0017] Furthermore, S2 specifically includes:

[0018] During the remote guidance phase, after receiving the attack command from the ground command system, the satellite platform, with the information support of the telemetry and control subsystem and the space / ground-based monitoring subsystem, performs orbital rendezvous with the space target until it approaches to within 200km of the target;

[0019] During the short-range guidance phase, with the guidance information from the space / ground-based surveillance subsystem and its own detection system, the satellite platform further maneuvers to approach the target to within 50km.

[0020] During the autonomous approach phase, the satellite platform's own detection system acquires the target, maintains continuous tracking of the space target, and further approaches the space target to within 10km to conduct close-range observation of the space target;

[0021] During the hovering observation segment, the satellite platform performs orthogonal plane hovering and control around the space target, guiding the satellite platform's perspective payload to perform preliminary three-dimensional tomographic imaging of the space target's internal structure, obtaining the target's internal structural feature information, and performing intelligent planning and refinement of the perspective task; in addition, before the satellite platform's perspective payload performs the perspective task, it is necessary to first conduct a preliminary understanding of the target based on the target satellite's external appearance information and prior information on the target satellite's internal structure.

[0022] In the segment where the patrol robot is dispatched, the satellite platform releases or retrieves the patrol robot;

[0023] During the standby flight phase, in response to the mission completion signal, the satellite platform moves away from the space target and enters a standby state.

[0024] Furthermore, in step S3, performing spatial perspective on the spatial target includes:

[0025] The system consists of four segments: dispatching and receiving patrol robots, guided flight, autonomous approach, flyaround observation, following and docking, contact landing, patrol and observation, and return and carry-on.

[0026] Furthermore, S3 specifically includes:

[0027] In the dispatching and retrieval of the patrol robot segment, the patrol robot is carried into a predetermined orbit. At a distance of 10km from the space target, the patrol robot is released and separated from the carrying platform with the assistance of a release locking mechanism.

[0028] During the guided flight phase, the cruise robot, supported by guidance information from the satellite platform, maneuvers from its release position to a distance of 5 km from the space target.

[0029] During the autonomous approach phase, the patrol robot's own detection system captures the target, continuously tracks the spatial target, and approaches it to within 400m, conducting close-range observation of the spatial target.

[0030] During the fly-around observation segment, the patrol robot performs orthogonal plane fly-around and hovering control on the space target, guiding the camera to perform three-dimensional reconstruction of the space target and obtain detailed feature information of the space target;

[0031] During the following flight and docking phase, the patrol robot determines the landing point based on the result of the three-dimensional reconstruction, and maintains a follow-flying approach to the landing point, docking at the landing point at a distance of 1m from the spatial target;

[0032] During the contact and landing phase, the four-legged mechanism of the cruise robot unfolds, and it approaches the space target from the docking point. The attached feet contact the surface of the space target and establish a connection with the space target.

[0033] In the cruise perspective segment, the cruise robot determines the cruise landing point and cruise path according to the task requirements, prior internal structure information, star surface conditions and perspective integrity, and feeds back the image generation quality and optical path analysis to the payload pose control to carry out the cruise perspective task.

[0034] During the return phase, the patrol robot returns to its original mounting platform.

[0035] Furthermore, the perspective load is a backscattered load, including:

[0036] A spot-scan X-ray source, including a small focal spot X-ray source and a vertical scanning mechanism;

[0037] Large-area X-ray detector, including a left-side detector and a right-side detector;

[0038] The control and processing subsystem includes an acquisition and control module and a data processing module. The acquisition and control module is connected to the spot-scan X-ray source and the large-area X-ray detector, respectively, and the data processing module is connected to the acquisition and control module.

[0039] Furthermore, the vertical scanning mechanism includes a chopper disk with multiple slits arranged at equal angles along the circumference. The slits extend radially, and the width of the slits gradually increases from the edge towards the center. Each slit has a protrusion on one side located on the chopper disk.

[0040] The space perspective method of this invention applies perspective technology to space and can be used to detect the internal structure of space targets. For example, it can be used to determine damage or wear of the internal structure of one's own spacecraft, which is conducive to timely repair or maintenance.

[0041] The spatial perspective method of this invention uses a patrolling robot to achieve close-range detection of spatial targets in the spatial dimension, which can achieve high-precision and high-efficiency detection and meet engineering requirements. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic flowchart of the spatial perspective method according to an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the internal structure of a typical satellite platform;

[0045] Figure 3 This is a schematic diagram of a detection method using a transmission load.

[0046] Figure 4 This is a schematic diagram showing the azimuth angle of the scattered photons in a backscattered transmission.

[0047] Figures 5-6 This is a schematic diagram of detection using a backscattered load.

[0048] Figure 7 A diagram illustrating the camera's capture of the target;

[0049] Figure 8 A schematic diagram showing the deployment of the satellite system;

[0050] Figure 9 This is a diagram illustrating the deployment of the patrol robots.

[0051] Figure 10 This is a schematic diagram of long-distance X-ray tomography.

[0052] Figure 11 This is a schematic diagram illustrating the principle of X-ray long-distance tomography.

[0053] Figure 12 This is a schematic diagram of the perspective load structure according to an embodiment of the present invention;

[0054] Figure 13 This is a schematic diagram of the overall process of perspective imaging according to an embodiment of the present invention;

[0055] Figure 14 This is a schematic diagram of the overall structure of the perspective load according to an embodiment of the present invention;

[0056] Figure 15 This is an exploded structural diagram of the perspective load according to an embodiment of the present invention;

[0057] Figure 16 This is a schematic diagram of a disc-chopper-type spot scanning X-ray source according to an embodiment of the present invention;

[0058] Figure 17 This is a schematic diagram of the point scanning mechanism according to an embodiment of the present invention;

[0059] Figure 18 This is a schematic diagram of the chopper disk according to an embodiment of the present invention;

[0060] Figure 19 This is a simulation analysis diagram of the transmission X-ray path in an embodiment of the present invention;

[0061] Figure 20 This is a schematic diagram of the mass coefficient simulation curve of the second segment of the transmission type in the simulation analysis of an embodiment of the present invention;

[0062] Figure 21 The transmittance curve of X-ray photons for a 30mm thick aluminum-magnesium alloy skin in the simulation analysis of an embodiment of the present invention;

[0063] Figure 22 This is a schematic diagram illustrating the relationship between the number of emitted photons and the number of incident photons in the first stage of the backscattering process in the simulation analysis of an embodiment of the present invention.

[0064] Figure 23 This is a graph showing the relationship between the number of backscattered photons and the incident X-ray photon energy at each scattering angle direction in the second stage of the backscattering process in the simulation analysis of this embodiment of the invention.

[0065] Figure 24 This is a simulation analysis of the backscattered photon number distribution at various scattering angles when the backscattered second-stage X-ray source is 140 keV in an embodiment of the present invention.

[0066] Figure 25 This is a graph showing the relationship between the number of scattered photons at each scattering angle direction and the incident X-ray photon energy in the simulation analysis of the second stage of the backscattering method in this embodiment of the invention.

[0067] Figure 26 This is a simulation analysis of the relationship between signal intensity and scattering angle after the backscattering third stage penetrates the skin in an embodiment of the present invention. Detailed Implementation

[0068] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0069] The descriptions of the embodiments herein, including any references to directions and orientations, are for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0070] like Figure 1 As shown, an embodiment of the present invention provides a spatial perspective method, comprising:

[0071] S1: Obtain prior information about the spatial target and complete the initial intelligent planning for the perspective task;

[0072] S2, deploy the see-through satellite system carrying the patrol robot relative to the space target, wherein the patrol robot is equipped with a see-through payload;

[0073] S3, the patrol robot performs a spatial perspective task on the spatial target based on the prior information.

[0074] The following provides a detailed explanation of each step:

[0075] In step S1, prior information about the spatial target is obtained, mainly the internal structure information of the target. This internal structure information serves as a preliminary understanding of the target and is used by the perspective payload on the patrol robot to perform perspective tasks.

[0076] Because a satellite is a hierarchical functional system, it is divided into three levels: equipment / components, subsystems, and the entire satellite. Equipment / components primarily perform a specific function, such as star sensors for attitude measurement and batteries for energy storage and release. Subsystems are composed of multiple closely coupled devices / components, which are completed through functional division and coupling. For example, the control subsystem consists of multiple measurement sensors, actuators, and a control computer, realizing the attitude measurement and pointing control of the entire satellite. The payload also exists as a subsystem, being the core subsystem that directly executes the satellite's flight mission, such as optical detection payloads and SAR payloads. The design and implementation of other subsystems are based on the requirements of the payload subsystem and the flight mission requirements. The entire satellite consists of the payload subsystem and multiple platform subsystems, achieving specific flight missions under corresponding orbital space environment conditions.

[0077] like Figure 2 As shown, the main hardware components of a typical satellite include:

[0078] (1) Payload Subsystem

[0079] For example, optical detection payloads and SAR detection payloads are used to perform specific flight missions: optical detection payloads are used to realize optical imaging observation of the earth and mainly include optical systems, focal plane arrays, data processing units, control units, etc.; SAR payloads are used to realize radar observation of the earth and mainly include SAR antennas, monitoring computers, digital modules (digital acquisition and forming devices), radio frequency modules, etc.

[0080] (2) Attitude Measurement and Control Subsystem

[0081] Used for satellite attitude measurement and pointing control, it mainly consists of measurement sensors, actuators, and a control computer. Specifically, the measurement sensors include star sensors, solar sensors, infrared Earth sensors, inertial measurement units, magnetometers, etc.; the actuators include reaction wheels, torque gyroscopes, magnetometers, etc.; and the control computer.

[0082] (3) Promote the subsystem

[0083] It provides thrust and thrust torque for satellite orbit control and attitude maneuver control, and is mainly composed of propellant tanks, gas cylinders, thrusters, pipelines, valves and other parts.

[0084] (4) Satellite structure subsystem

[0085] It is used to provide installation interfaces and equipment installation benchmarks, and mainly consists of main load-bearing structures, mounting structure plates, and auxiliary structural components.

[0086] (5) Thermal control subsystem

[0087] It is used to control the temperature of the entire satellite and mainly consists of a thermal controller, thermal control coating, multi-layer thermal insulation material, heat pipe, temperature measurement and control circuit, etc.

[0088] (6) Measurement and Control Subsystem

[0089] It is used for transmitting telemetry and control commands with ground telemetry and control stations and mainly consists of telemetry and control antennas and telemetry and control transponders.

[0090] (7) Data transmission subsystem

[0091] It is used for payload data storage and downlink, and mainly consists of a data transmission antenna, a data transmission transmitter, and a memory.

[0092] (8) Power supply subsystem

[0093] It is used for satellite power generation, storage and distribution control, and mainly consists of solar cell arrays, battery packs, power controllers, and power distributors.

[0094] (9) Data Management Subsystem

[0095] It is used to control and manage the satellite's data and operating status, and mainly consists of an onboard computer, a lower-level computer, and a telemetry and remote control unit.

[0096] Common satellite platforms include Boeing's BSS-601 series platform, BSS-702 platform, GEM platform, and Lockheed Martin's A2100 series platform.

[0097] In step S2, the perspective satellite system includes a satellite platform, a patrol robot and target acquisition device mounted on the satellite platform, and a perspective payload mounted on the patrol robot. The perspective payload mounted on the patrol robot mainly includes a transmission payload, a backscattering payload, or a combination of both. Details are as follows:

[0098] (1) Satellite platform

[0099] The satellite platform adopts long-range tomography satellites, such as the Dongfanghong-3 satellite, which carries a perspective payload and serves as a long-range tomography satellite.

[0100] (2) Patrol robots

[0101] The satellite surface rovers are space robots capable of attaching to and climbing on satellite surfaces. They can carry different payloads according to specific needs, traversing and roaming the surface of target spacecraft to perform various tasks. These robots can also reside on the surfaces of our high-value satellites, conducting patrols, protection, and on-orbit maintenance.

[0102] The patrol robot is released from its platform, rapidly maneuvers to the vicinity of the target satellite, performs a landing maneuver, and attaches itself to the target surface. Upon receiving the operational mission command, the robot climbs to a designated location on the satellite surface and performs X-ray observation of the target based on its payload. After completing the mission, the robot autonomously detaches from the target surface and returns to the platform, as required. The entire process of the patrol robot is divided into the launch and orbit insertion phase, the guided flight phase, the autonomous approach phase, the fly-around observation phase, the follow-up flight and docking phase, the contact landing phase, and the patrol and combat phase.

[0103] (3) Perspective load

[0104] The perspective payload is carried by the patrolling robot and includes the following three forms:

[0105] (3.1) Transmission load

[0106] Ground-based tomography primarily uses transmission-based imaging. The advantage of transmission-based imaging is its rich image information, but it requires the radiation source and detector to work together on both sides of the target. As a space payload, it requires two spacecraft to operate in coordination, such as... Figure 3 As shown, the process is relatively difficult. However, the images obtained through transmission are relatively detailed and can reveal minute internal structures of the target object. When X-rays penetrate matter, their intensity decreases due to absorption and scattering by the material. Different parts of the target object absorb and scatter X-rays differently due to variations in material and thickness, resulting in different signals reaching the detector. These differences are used to form an image.

[0107] (3.2) Backscattered load

[0108] Backscattering imaging utilizes the Compton scattering principle, where incident photons are scattered by inelastic collisions with the outer electrons of atoms in matter.

[0109] like Figure 4 The diagram shows the azimuth distribution of scattered photons. By identifying the locations where X-ray backscattered signals are strongest, data can be provided to support the optimization of the system payload's attitude, relative position, and detector panel.

[0110] like Figure 5 As shown, backscattering requires a relatively simple satellite platform; the radiation source and detector can be placed on two separate spacecraft on the same side of the target, or integrated onto the same spacecraft. It features miniaturized integration, simple operating modes, and ease of space application. However, due to the different backscattering mechanism, the light path must be reflected twice through the satellite's surface septum, resulting in a relatively weak signal obtained by backscattering.

[0111] like Figure 6The diagram shows a backscatter imaging system. The emitting source and the receiving detector can be integrated onto a single spacecraft. The emitting and receiving spacecraft can also coordinate and fly in formation to the vicinity of the target spacecraft, performing ranging, angle measurement, and other methods to locate it. By controlling the emitting and receiving detectors to fly to the same side of the celestial body's surface, the target can be imaged.

[0112] (3.3) Combination of transmission and backscattering

[0113] Transmission and backscattering are the two main detection optical path modes in transmission technology. When satellite platform conditions permit, a combination of transmission and backscattering can be considered to achieve higher target identification accuracy.

[0114] (4) Target acquisition device

[0115] The target acquisition device includes a target acquisition camera, a lidar, and a binocular camera.

[0116] (4.1) Target acquisition camera

[0117] The target acquisition camera can capture targets, enabling the penetrating payload to accurately align with non-cooperative targets. The photon counting detection method employs a stitched-together field-of-view approach from multiple detection units, covering a 4π spatial domain, such as... Figure 7 As shown, a single system consists of 5 detection units, covering a 2π spatial domain; two systems combined can cover a 4π spatial domain. Each sensing unit comprises a broadband photon counting detector and a front-end large field-of-view optical system. The detector processing circuitry calculates the position of arriving photons relative to the target surface, thus achieving spatial positioning. Due to the use of a field-of-view stitching staring imaging method, the detection real-time performance is high (1kHz).

[0118] (4.2) LiDAR and binocular camera

[0119] The product utilizes lidar and a binocular camera for ranging of non-cooperative targets, meeting the guideline requirement of ≥10km range perspective. The lidar and binocular camera can simultaneously perform azimuth and six-degree-of-freedom information measurement for cooperative targets and 3D imaging and pose measurement for non-cooperative targets. The product has significant application prospects in rendezvous and docking, space situational awareness, space control, and especially in missions involving multi-functional space-to-ground reciprocating vehicles.

[0120] like Figure 8 As shown, in step S2, the deployment of the perspective satellite system to the space target includes:

[0121] ① Long-range guidance phase (-200km): After receiving the attack command from the command and control system, the long-range tomographic imaging satellite, with the information support of the telemetry, tracking and command subsystem and the space / ground-based monitoring subsystem, conducts rapid orbital rendezvous with the target until it approaches the target at a suitable position.

[0122] ② Short-range guidance phase (200km-50km): With the guidance information from the space / ground-based surveillance subsystem and its own detection system, the long-range tomography satellite rapidly maneuvers to approach the target to a distance of 50km.

[0123] ③ Autonomous Approach Segment (50km-10km): The long-range tomographic imaging satellite's own detection system acquires the target, maintains continuous tracking of the target, and further approaches the target to 10km for close-range observation.

[0124] ④ Hovering and Observation Segment (10km): The long-range tomographic imaging satellite performs orthogonal plane hovering and control around the target satellite, guiding the perspective payload to perform internal three-dimensional tomographic imaging of the target and obtain internal structural feature information. Before the perspective is executed, a preliminary understanding of the target is required based on the target satellite's external appearance information and prior internal structural information, in order to prepare for subsequent perspective inversion mission planning.

[0125] ⑤ Deployment and Retrieval of Patrol Robots (10km): The long-range tomographic imaging satellite serves as a platform for releasing and retrieving patrol robots to achieve the purpose of eliminating threat sources or conducting detailed threat assessments.

[0126] ⑥ Standby Flight Phase: After mission completion, the long-range tomography satellite moves away from the target satellite and enters standby mode to prepare for the next mission.

[0127] like Figure 9 As shown, according to step S2, the perspective satellite system is deployed 10km behind the target, and then step S3 is entered, where the patrol robot performs a spatial perspective mission on the target:

[0128] ① Entering the dispatch and collection patrol robot segment (-10km): The patrol robot is carried into the predetermined orbit. At a distance of about 10km from the target, the patrol robot is released and separated from the carrier platform with the assistance of the release locking mechanism.

[0129] ② Short-range guidance segment (10km-5km): With the guidance information from the platform, the patrol robot quickly maneuvers from the release position to approach the target at a distance of 5km.

[0130] ③ Autonomous Approach Phase (5km-400m): The patrol robot's own detection system captures the target, continuously tracks the target, and further approaches the target to 400m for close-range observation.

[0131] ④ Flyaround observation and 3D reconstruction section (400m): The patrol robot performs orthogonal plane flyaround and hovering control on the target star, guiding the camera to perform 3D reconstruction of the target and obtain detailed feature information of the target.

[0132] ⑤ Follow-up and docking phase (400m-1m): The patrol robot determines the landing point based on the target's 3D reconstruction results and keeps following and approaching the landing point, docking at the landing point at a distance of about 1m from the target.

[0133] ⑥ Contact and landing phase (1m-0m): The four-legged mechanism of the patrol robot unfolds, and it approaches the target from the docking point. The attached feet contact the target surface and establish a connection with the target.

[0134] ⑦ Cruise Perspective Segment: First, path planning is performed, including determining the cruise landing point and cruise path based on mission requirements, prior target internal structure information, star table conditions, and perspective integrity; then, optical path selection optimization control is performed, including feeding back to the payload pose control based on image generation quality and optical path analysis; finally, internal structure inversion is performed to quickly identify effective targets and effective locations, and to evaluate the effectiveness of the stealth combat module.

[0135] ⑧ Return to the carrier spacecraft: After the mission is completed, the patrol robot returns to the carrier spacecraft to replenish fuel and power, and prepares for the next mission.

[0136] In steps S2 and S3, the perspective load technology solution mounted on the patrol robot is as follows:

[0137] like Figure 10 As shown, addressing the need for miniaturization and low power consumption in space X-ray imaging, this embodiment proposes a point-scan modulation backscatter imaging method. This eliminates the limitations of optical lenses or collimators at the front end of the detector, increases the detector surface size, improves receiving efficiency, reduces X-ray source power consumption, and is more conducive to space applications. Therefore, it can be carried on a long-range tomographic imaging satellite to perform local scanning detection of the target satellite surface or panoramic scanning detection of the target satellite interior.

[0138] like Figure 11 As shown, the basic principle of an X-ray scanning backscatter imaging payload is as follows: the light source radiates X-rays, which are controlled by a vertical scanning mechanism (slit and chopper) to scan point by point in the vertical direction, while the entire unit moves at a constant speed in the horizontal direction, completing a two-dimensional scan of the imaging surface. Simultaneously, the detector receives the target backscatter signal, converts it into an electrical signal, and transmits it to the control and processing subsystem. This subsystem uses algorithms to reconstruct the time-series electrical signal into a two-dimensional backscatter image of the target.

[0139] like Figure 12As shown, this embodiment of the invention proposes a scanning backscattering imaging system as the payload, which mainly consists of three subsystems: a point-scanning X-ray source, a large-area X-ray detector, and a control and processing system. The point-scanning X-ray source, composed of a small-focal-spot X-ray source and a vertical scanning modulation mechanism, is primarily responsible for generating high-brightness, small-focal-spot X-rays and performing point-by-point scanning in the vertical direction. The large-area X-ray detector, composed of two large-area X-ray detection units (left and right), is primarily responsible for converting scattered X-rays into electrical signals via photoelectric conversion. The control and processing subsystem, composed of an acquisition control module and a data processing module, is primarily responsible for controlling the light source and mechanism, acquiring detector signals, and performing image processing and output.

[0140] like Figure 13 As shown, the overall process of using the above-mentioned scanning backscatter imaging system for perspective imaging is as follows: ① The device is powered on and, after initialization, enters a waiting state; ② A scanning command is initiated, and the device begins to run the scanning process, including beam output and acquisition, while the robot carrying the device moves at a constant speed on the surface of the object being inspected; ③ The scanning result is directly output to the robot, which observes the result and makes a judgment; ④ The device returns to the waiting state; ⑤ The above steps are repeated for the next target.

[0141] like Figure 14 The diagram shows a schematic of the fluoroscopic payload mounted on the patrol robot according to an embodiment of the present invention. Common point-scan X-ray sources all require a fan-shaped collimator to be fixed at the beam exit position to modulate the conical X-ray beam into a fan-shaped beam emitted in the horizontal or vertical direction. The difference lies in the modulation method of the fan-shaped beam. Considering that this embodiment is applied to spatial fluoroscopy, the complexity of processing and assembly, and the requirements of the detector on the overall size and weight, combined with the specific structure of the X-ray source used, this embodiment adopts a disc chopper-type point-scan generation method.

[0142] like Figure 15 and Figure 16As shown, a disc-chopper-type spot-scan X-ray source mainly consists of a sector collimator, a chopper disk, a motor drive, and an X-ray source. The conical X-ray beam emitted from the X-ray source passes through the sector collimator, forming a sector-shaped beam. This beam is then driven to rotate by a chopper disk with a concentric slit near its edge. The disk absorbs most of the X-rays, leaving only a pen-shaped beam moving up and down where the slit and the sector beam intersect. The X-ray source is controlled via a communication interface. In practice, when the scanning program starts, the FPGA first determines if the X-ray source meets the beam emission conditions. If so, the FPGA sends a command to the X-ray source according to the communication protocol to control the beam emission. Conversely, if the scanning program is terminated during the scan, the FPGA sends a stop command to the X-ray source, and the X-ray source immediately stops emitting the beam. Currently available commercial backscatter X-ray tubes, after initial ground-based experimental source testing according to this invention, do not meet the requirements of space payloads in terms of operating temperature and heat dissipation methods. Based on the ground test data, a customized space-scale miniaturized X-ray source was developed to meet the requirements in terms of performance parameters and adaptability to the space environment.

[0143] like Figure 17 As shown, the point scanning mechanism uses a high-speed rotating chopper to chop a collimated fan-shaped X-ray beam, forming a fine X-ray beam that scans vertically at high speed. Specifically, X-rays are emitted from the center of the light source and collimated into a fan-shaped beam after passing through a pre-positioned slit. A high-speed rotating chopper wheel is positioned at the exit of the collimating slit. Several slits are radially distributed on the surface of the chopper wheel, and the portion outside the slits is shielded from X-rays using high-atomic-number, high-density tungsten material. During the high-speed rotation of the chopper wheel, the collimated fan-shaped X-ray beam can pass through the slits on the chopper wheel for a certain period, thus forming a fine beam that scans vertically at high speed. This fine beam irradiates the object under test, producing Compton scattering. The image is acquired by receiving the backscattered signal from the object under test. The point scanning mechanism is driven by a common stepper motor.

[0144] like Figure 18As shown, the design of a backscatter imaging system requires that only one pencil-shaped X-ray beam be projected onto the object being detected at any given time. The length of the exit aperture of the fan-shaped collimator determines the lower limit of the disk diameter to ensure that no two adjacent slits can simultaneously intersect with the fan-shaped X-ray beam. In this embodiment of the invention, the fan-shaped collimator modulates the conical X-ray beam emitted from the light source into a fan-shaped beam with an angle of 40° both vertically and horizontally. Considering the limitations on the disk diameter due to machining precision and the internal spatial structure of the instrument, and while allowing a certain time margin between each data acquisition, this embodiment of the invention ultimately determines the disk diameter to be 70mm, with five slits cut at an equal angle of 72°. The chopper disk needs to be processed using materials with high atomic numbers (such as tungsten, lead, etc.), and there are also certain requirements for the disk thickness to ensure that it can absorb most of the X-rays except for the light spot. Due to the influence of the disk thickness, the spot formed by the intersection of the fan-shaped X-ray beam and the slit has a shape that is small at both ends and large in the middle along the scanning path. To compensate for this defect, the slit is designed as a wedge shape with the widest edge and the narrowest width closer to the center.

[0145] In addition, each slit on the chopper disk corresponds to a column in the scanning process. In order to determine the position of the light spot, the starting point signal of each column is needed. By installing a protrusion next to each slit and fixing a proximity sensor at a specific position on the disk support, the signal triggered by each protrusion when it passes the sensor during the rotation of the disk corresponds exactly to the start of the next slit intersecting with the fan-shaped beam, marking the start of a new column of scanning.

[0146] The rotational speed of the disk is determined by the spot size and the platform translation speed. For simplicity, we take the midpoint of a column scan as an example. Assuming the platform translation speed is V, the actual spot spacing between adjacent pixels in the image is L (i.e., each pixel corresponds to a square with side length L), and the disk rotation period is T, then the scanning time interval for each column is T / 5 (there are a total of 5 slits). Ideally, L = T × V / 5, so T = 5L / V can be calculated. In this project, the minimum slit width is designed to be 0.4 mm, the spot width projected onto the object being inspected is 2.4 mm (i.e., L = 2.4 mm), and the platform translation speed is designed to be 12 mm / s. Therefore, T = 1 s, meaning the disk rotation speed is 60 rpm.

[0147] It is worth noting that the uniform rotation of the disk means that the angular velocity of the light spot moving up and down the target being detected is the same. However, the distance from the light spot to the target point of the light source varies depending on the position of the light spot projected onto the object being detected. This creates a long-short-long variation trend on the same scanning line. If the acquisition time of each pixel on a scanning line is fixed, it will cause the scanning speed at the top and bottom to be too fast, resulting in the edge of the scanned image being stretched and distorted.

[0148] The following is a simulation analysis of the space transmission system according to an embodiment of the present invention:

[0149] When X-ray photons are incident on the target material, the scattered photons are emitted at a 4π solid angle. The specific cross-section where Compton scattering occurs is closely related to the energy and direction angle of the incident X-ray photons. Generally, the higher the energy of the incident photons, the more forward-facing the scattered photons. For backscattering imaging devices, the scattering angle of the detected photons is greater than 90 degrees. To obtain high-intensity scattered photons, the energy of the incident X-ray photons should be selected in a relatively low range, while still possessing a certain ability to penetrate matter. For transmission imaging devices, the scattering angle of the detected photons is less than 90 degrees, and higher energy photons have higher transmittance. Therefore, while ensuring the contrast of the imaging target and the power consumption of the light source, the energy of the incident X-ray photons should be selected in a relatively high range.

[0150] (1) Transmission simulation analysis

[0151] like Figure 19 As shown, a simulation analysis is first performed on the transmission method: Figure 26 This is the X-ray optical path diagram for transmission tomography. For simplicity, it is assumed that the X-ray propagation path remains unchanged after passing through the skin. The entire optical path analysis is divided into four segments: the X-ray photons emitted from the X-ray source reach the front end of the satellite after 10km of geometric attenuation (segment 1); the transmission attenuation occurs through the aluminum-magnesium honeycomb skin at the front end of the satellite (segment 2); the transmission attenuation occurs through the target to be imaged (segment 3); and the transmission attenuation occurs through the aluminum-magnesium honeycomb skin at the rear end of the satellite (segment 4). Since the size of the satellite (0.5-5m) is small compared to its distance from the X-ray source (10km), the geometric attenuation it causes can be ignored in this simulation analysis. Other simulation parameters include the divergence angle of the X-ray source (80°). o The X-ray light flux is 1×10¹² photons per second per square centimeter (counts / s / cm²), the flat panel detector size is 30cm×30cm (Shanghai Yuying Commercial X-ray Flat Panel Detector), the single pixel area is 100μm, the scintillator light yield is 1×10⁴ counts / MeV, the imaging signal-to-noise ratio is 10, and the target to be imaged is the circuit board inside the satellite service module (size 20cm×10cm).

[0152] For the first segment, the geometric attenuation rate of the X-ray photon after propagating 10 km from the source to the imaging focal plane is:

[0153]

[0154] For the second segment, the mass weighting of aluminum / magnesium in the honeycomb panel skin was selected as 95:5. The simulation results of the mass absorption coefficient µm calculated using Xmudat software are as follows: Figure 20 As shown.

[0155] According to the formula:

[0156] (1)

[0157] in The linear absorption coefficient is... The thickness of the skin, the mass absorption coefficient , Given the density of the aluminum-magnesium alloy, and considering that the satellite's aluminum-magnesium alloy skin has a honeycomb panel structure, Selected as 0.5 times the standard aluminum-magnesium alloy plate, which is 1.35. The transmittance curves of photons of different energies penetrating a 30mm thick aluminum-magnesium alloy skin, calculated using the mass absorption coefficient obtained from Xmudat simulation, are shown below. Figure 21 As shown in the figure, for transmission imaging, 100 keV is the most economical operating frequency (transmittance of 50.13%), because the increase in transmittance gradually slows down above 100 keV. For 140 keV photons emitted by currently commercially available optical tubes and 50 keV photons emitted by reflective tungsten target X-ray tubes, the transmittance probabilities are 56% and 22.68%, respectively.

[0158] For the third segment, the mass absorption coefficient was calculated using Xmudat software, and the probabilities of 140keV, 100keV and 50keV photons penetrating a 1cm thick polytetrafluoroethylene plate were calculated using formula (1) as 74%, 71.89% and 62.57%, respectively.

[0159] For the fourth segment, the same as the first segment, the probabilities of 140keV, 100keV and 50keV photons penetrating a 30mm thick aluminum-magnesium alloy plate are 56%, 50.13% and 22.68%, respectively.

[0160] Therefore, combining the above four points, the X-ray photon fluxes of 140keV, 100keV, and 50keV photons emitted from the X-ray source, passing through the circuit board to be imaged and reaching the detection focal plane, are 164 photons / s, 128 photons / s, and 23 photons / s, respectively. After scintillator multiplication, the number of visible light photons incident on a single pixel on the amorphous silicon panel is 1.15 photons / s / pixel, 0.64 photons / s / pixel, and 0.0075 photons / s / pixel, respectively. Therefore, an ultra-high sensitivity single-photon detector with single-photon counting capability and a sufficiently low dark count rate (on the order of mHz) is required to achieve effective tomographic imaging.

[0161] (2) Backscattering simulation analysis

[0162] For backscattering imaging, the relationship between the scattered photon energy, the incident photon energy, and the scattering angle is as follows:

[0163]

[0164] in, , These are the scattered photon energy, the incident photon energy, and the scattering angle, respectively.

[0165] X-ray intensity simulation calculation in backscattered optical path mode:

[0166] The propagation path was divided into five parts: source-skin stage I-circuit board reflector-skin stage II-detector. A Compton scattering model of electromagnetic fields on stationary electrons was used to simulate the backscattered photon energy distribution in the circuit board reflector segment. For X-ray sources with different photon energies, the numerical values ​​of X-ray intensity in the skin penetration stage I, the back reflection of the target circuit board, and the skin penetration stage II were simulated, along with their dependence on system parameters such as X-ray source photon energy, light intensity, and skin thickness. Specifically, the attenuation and reflection patterns of the total number of X-ray photons in each propagation path segment were simulated when the X-ray source photon energy was 140 keV.

[0167] X-ray penetration of skin stage I

[0168] like Figure 22 As shown, the X-rays emitted from the light source first pass through a 3-centimeter star surface skin, and their intensity attenuation follows the formula I1 / I0=e(-c×x), c=u / ρ. Assume the X-ray source intensity in this project is 10... 11 In the case of / sr / s, the relationship between the emitted light intensity and the incident light intensity is characterized by: Figure 22 As shown.

[0169] X-rays produce a Compton scattering effect at the target.

[0170] The X-rays produce a Compton scattering effect at the target. Using the Compton scattering model of an electromagnetic field on stationary electrons, the energy distribution of backscattered photons from the reflective surface of the circuit board was calculated. The intensity distribution of the reflected light in each scattering direction and its dependence on the X-ray source photon energy are shown below. Figure 23 As shown in the figure, under the condition of vertical incidence, the backscattered signal is strongest at the azimuth with a reflection angle of 90 degrees (corresponding to a scattering angle of 180 degrees).

[0171] When the X-ray source is 140 keV, the intensity distribution of backscattered light in all directions is as follows: Figure 24 As shown, the signal reaches its optimal value at a scattering angle of 180 degrees. The number of photons per solid angle in this direction is 8.5 × 10⁻⁶. 5 / sr / s.

[0172] To characterize the proportion of backscattered energy in this process, the omnidirectional energy distribution at the target was simulated, such as... Figure 25 As shown, when the source photon energy is 140 keV, the reflected energy on the target surface is relatively weaker than the scattering intensity along the X-ray incident direction. Combined with... Figure 25 The data shows that, in order to obtain a larger proportion of X-ray backscattered signals, an X-ray source with relatively low photon energy can be selected.

[0173] ③ X-ray penetration stage II

[0174] During this stage, the X-rays reflected from the target return and penetrate 3 cm of the star surface skin, and their intensity attenuation follows the formula I1 / I0=e(-c×x), c=u / ρ. For example... Figure 26 As shown, this characterizes the dependence of the outgoing light intensity on the incident light intensity. From Figure 26 It can be seen that after the X-rays return from the target and penetrate the 3 cm skin for the second time, the signal reaches the optimized value of 5.6 × 10⁻⁶ in the direction of scattering angle of 180 degrees. 5 / sr / s.

[0175] In summary, when the X-ray source energy is between 50 keV and 200 keV, the signal attenuates after two backscattering events through the skin and one backscattering event from the target, resulting in a relatively strong signal returning in the opposite direction of the incident light. When the X-ray source photon energy is 140 keV and the target is incident perpendicularly, the number of scattered photons per unit solid angle of the reflecting surface is optimal in the direction of a 90-degree reflection angle (180-degree scattering angle) for the X-ray backscattered signal. To obtain a larger proportion of the X-ray backscattered signal, an X-ray source with relatively lower photon energy can be selected, provided conditions permit. Furthermore, the above simulations provide data support for optimizing the attitude, relative position, and detector panel design of the system payload.

[0176] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of spatial perspective, characterized by, The application relates to a space target perspective system and a perspective method thereof. S1, acquiring prior information of a space target, and completing preliminary intelligent planning of a perspective task; The prior information is internal structure information of the space target, and the internal structure information comprises a payload subsystem, a thermal control subsystem, a propulsion subsystem, a power supply subsystem, a data processing subsystem, a satellite structure subsystem, an attitude measurement and control subsystem, a TT&C (telemetry, tracking and command) subsystem and a data transmission subsystem; S2, deploying a perspective satellite system loaded with a cruising robot relative to the space target, wherein the cruising robot is loaded with a perspective load; the perspective satellite system further comprises a satellite platform, the cruising robot is loaded on the satellite platform, and a target capturing device is further arranged on the satellite platform; the perspective load comprises a transmission load, a backscattering load or a combined load of the transmission load and the backscattering load; the perspective load comprises a perspective load of the satellite platform and a perspective load on the cruising robot; the target capturing device comprises a target capturing camera, a laser radar and a binocular camera; S3, the cruising robot performs a space perspective task on the space target according to the prior information; the space perspective on the space target comprises a cruising robot sending and collecting segment, a guided flight segment, an autonomous approaching segment, a fly-around observation segment, a follow-up parking segment, a contact landing segment, a cruising perspective segment and a return carrying segment; The S3 specifically comprises the following steps. In the cruising robot sending and collecting segment, the cruising robot is carried to fly into a predetermined orbit, and is released from a carrying platform under the assistance of a release locking mechanism at a position 10km away from the space target; In the guided flight segment, the cruising robot is guided to the space target 5km away from the release position under the guidance of the satellite platform; In the autonomous approaching segment, a self-detection system of the cruising robot captures the target, keeps tracking of the space target and further approaches the target to a distance of 400m, and performs close-range observation on the space target; In the fly-around observation segment, the cruising robot performs orthogonal surface fly-around and hovering control on the space target, guides a camera to perform three-dimensional reconstruction on the space target, and obtains detailed feature information of the space target; In the follow-up parking segment, the cruising robot determines a landing point according to the three-dimensional reconstruction result, keeps follow-up approaching to the landing point, and keeps parking at a position 1m away from the space target; In the contact landing segment, a four-leg mechanism of the cruising robot is unfolded, the cruising robot further approaches the space target from the parking point, and an attachment foot contacts a surface of the space target to establish connection with the space target; In the cruising perspective segment, the cruising robot determines a cruising landing point and a cruising path according to a task demand, prior internal structure information, a star table condition and perspective integrity, feeds back a load pose control according to image generation quality and light path analysis, and performs a cruising perspective task; In the return carrying segment, the cruising robot returns to the original carrying platform.

2. The method of spatial perspective according to claim 1, wherein, In the S2, the perspective satellite system is deployed, and the satellite platform needs to complete the following operation processes: Deployment into orbit section, long-range guidance section, short-range guidance section, autonomous approach section, hovering observation section, dispatching and cruising robot section, standby flight section.

3. The method of spatial perspective according to claim 2, wherein, The S2 specifically comprises: In the long-range guidance section, the satellite platform receives the attack instruction from the ground command system, and under the information support of the TT&C subsystem and the space / ground-based monitoring subsystem, performs orbit intersection on the space target until approaching to the target at a distance of 200 km; In the short-range guidance section, the satellite platform further approaches to the target at a distance of 50 km under the guidance information support of the space / ground-based monitoring subsystem and its own detection system; In the autonomous approach section, the satellite platform's own detection system captures the target, keeps tracking the space target and further approaches to the space target at a distance of 10 km, and performs close-range observation on the space target; In the hovering observation section, the satellite platform performs orthogonal surface hovering and hovering control on the space target, guides the satellite platform's perspective load to perform preliminary three-dimensional tomography on the internal structure of the space target, obtains the internal structure characteristic information of the target, and performs intelligent planning and refinement of the perspective task; in addition, before the satellite platform's perspective load performs the perspective task, the target needs to be preliminarily recognized according to the appearance information of the target satellite and the prior information of the internal structure of the target satellite; In the dispatching and cruising robot section, the satellite platform releases or retrieves the cruising robot; In the standby flight section, in response to a task completion signal, the satellite platform moves away from the space target and enters a standby state.

4. The method of spatial perspective according to any one of claims 1-3, wherein, The perspective load is a backscattering load, which comprises: A point scanning X-ray source, including a small focal spot X-ray source and a vertical scanning mechanism; A large area array X-ray detector, including a left detector and a right detector; A control processing subsystem, including a collection control module and a data processing module, wherein the collection control module is connected with the point scanning X-ray source and the large area array X-ray detector, and the data processing module is connected with the collection control module.

5. The method of spatial perspective according to claim 4, wherein, The vertical scanning mechanism comprises a chopping disc, a plurality of slits are arranged on the chopping disc at equal angles in the circumferential direction, the slits extend in the radial direction, the width of the slits gradually increases from the edge to the direction close to the center of the disc, and each of the slits has a convex point on the chopping disc.

Images