Active space target super-resolution detection system and detection method

Abstract

An active space target super-resolution detection system and detection method belong to the field of space target detection technology. The present invention solves the problems of limited dim target detection capability and slow response speed caused by the existing space target detection system adopting a single passive detection method, as well as the problem that the existing space target detection system has poor target tracking accuracy when affected by the outside world, and is prone to turntable tracking lag and mechanical delay deviation. The laser phased array super-resolution imaging subsystem is used to scan and modulate the light beam through the laser phased array to achieve spectral and polarization multi-dimensional detection and imaging of space targets, and to achieve image super-resolution reconstruction and space target attribute recognition through the information processing subsystem. Compared with the existing technology, it has significant advantages in dim target detection and moving target tracking accuracy.

Description

Technical Field

[0001] The present invention relates to an active space target super-resolution detection system and a detection method, belonging to the technical field of space target detection. Background Art

[0002] With the rapid development of space technology, the space environment is becoming increasingly complex. A large number of space debris, including artificial satellites, launch vehicle debris, and abandoned spacecraft, fills Earth's orbit. This debris not only poses a serious threat to spacecraft in orbit but can also cause orbital collisions, leading to mission failures and even endangering the safety of astronauts. According to statistics from international space agencies, the number of space debris in orbit currently exceeds millions, with a particularly large number of debris ranging in size from 1cm to 10cm. The vast majority of this debris is located in key areas such as Low Earth Orbit (LEO), 2,000km above Earth, and Geosynchronous Orbit (GEO), 35,786km above Earth.

[0003] In recent years, satellite failures and malfunctions caused by space debris impacts have been increasing, resulting in significant economic losses and social impacts for global satellite applications such as communications, navigation, and meteorology. Furthermore, with the increasing pace of space activities by various countries, the amount of space debris continues to increase, and the potential threat it poses is becoming increasingly prominent. Overall, future development trends are placing higher demands on the longevity and reliability of satellites, while the space debris environment is becoming increasingly harsh. This resulting conflict necessitates the detection, protection, and active removal of space debris, especially small-scale space debris in low-Earth orbit. Effective means are needed to achieve precise detection, effective protection, and efficient removal. Achieving high-precision detection, orbit determination, and positioning of small-scale space debris, with a position error of better than 100-300 meters, would enable in-orbit spacecraft to effectively avoid collisions with space debris or other spacecraft.

[0004] Space debris detection and monitoring are key to solving this problem. However, space debris detection faces numerous technical challenges. For example, the dimness of the target leads to insufficient detection light energy, resulting in poor image signal-to-noise ratio and contrast, making it difficult to detect dim targets. The motion of the target causes its position to continuously change, leading to poor image stability and intensity balance, making it difficult to detect moving targets. The small size of the target leads to low spatial resolution, requiring high-tech image recognition and extraction techniques, making it difficult to detect small targets. Furthermore, interference factors such as starlight and Earth reflections in the complex background of space further complicate space debris detection.

[0005] To address the above issues, the invention patent application CN 118921105 A discloses an integrated space-based super-resolution imaging and ranging communication system for space targets. Based on a multi-dimensional super-diffraction sub-pixel imaging subsystem, this system simultaneously achieves diffraction super-resolution and sub-pixel super-resolution, maximizing the ability to identify target details, thereby resolving the problem of centimeter-level targets being dim, weak, and difficult to detect and identify. However, through the applicant's ongoing research in space target detection, the following issues were discovered:

[0006] 1. In terms of detection method, the system adopts a single passive detection method, that is, it receives sunlight through the target survey subsystem alone. It relies on the reflection of sunlight and has no active illumination source. As a result, its ability to detect dim targets is extremely limited. It also relies on mechanical scanning of the turntable, which has a slow response speed.

[0007] 2. In terms of target tracking accuracy, the system may temporarily lose the target during the switching process from coarse tracking to fine tracking, requiring recapture. Distance measurement needs to be triggered after fine tracking is completed, causing problems such as turntable tracking lag and mechanical delay deviation, further increasing response delay. Although the system states "control the galvanometer to keep the target continuously in the center of the field of view", this is only achievable under ideal conditions and without external influences. However, in practice, the closed-loop process from "imaging → processing → controlling the galvanometer" has inherent delays. During the delay, the target has significantly moved, and the galvanometer compensation lags, resulting in accumulated tracking errors, which will affect subsequent detection and imaging.

[0008] 3. In terms of super-resolution imaging methods, the system's reconstruction based on compressed sensing has the problem of dependence on initial conditions and sparsity, which means that its ability to recognize target features needs to be improved.

[0009] Therefore, there is an urgent need to further improve the system to overcome the above-mentioned problems currently existing in the system, solve its fundamental limitations in dim target detection, high-speed motion compensation, long-distance resolution and full-time domain working capabilities, and provide a new solution for centimeter-level precise monitoring of space debris. Summary of the Invention

[0010] The present invention aims to solve the problems of limited dim target detection capability and slow response speed caused by the existing space target detection system adopting a single passive detection method, as well as the problems of poor target tracking accuracy and proneness to turntable tracking lag and mechanical delay deviation when the existing space target detection system is affected by external factors. An active space target super-resolution detection system and detection method are provided.

[0011] The technical solution adopted by the present invention to solve the above technical problems is:

[0012] An active space target super-resolution detection system includes a target survey subsystem, a precision tracking detection subsystem, a target ranging subsystem, a laser phased control super-resolution imaging subsystem, an information processing subsystem, a tracking turntable subsystem and a master control subsystem, wherein:

[0013] The target survey subsystem is installed on the detection and tracking turntable. It is used to achieve long-distance detection of space targets using a high-sensitivity optical detection unit and obtain the position coordinates of the space targets through the information processing subsystem.

[0014] The precision tracking detection subsystem is used to perform high-frequency imaging of space targets using precision tracking detectors. It also controls the galvanometer based on the high-frequency imaging to ensure that the space target remains in the center of the field of view, achieving stable precision tracking.

[0015] The target ranging subsystem is used to achieve long-distance and high-precision ranging of space targets using laser ranging technology, and obtain the distance information of space targets through the information processing subsystem;

[0016] The laser phased array super-resolution imaging subsystem is used to scan and modulate the laser beam to achieve spectral and polarization multi-dimensional detection and imaging of space targets, and the information processing subsystem is used to achieve image super-resolution reconstruction and attribute recognition of space targets;

[0017] The information processing subsystem is used to synthesize multiple low-resolution images into a high-resolution image using synthetic aperture technology and super-resolution reconstruction algorithms through an integrated high-speed processing chip, and to calculate the position coordinates of space targets, the ranging information of space targets, and the attributes of space targets;

[0018] The tracking turntable subsystem is used to control the detection and tracking turntable according to the position coordinates of the space target to achieve tracking of the space target;

[0019] The master control subsystem is used to control the hardware power supply switch and self-test work of each subsystem;

[0020] The target ranging subsystem includes a high repetition rate laser transmitter, an optical fiber beam splitter, a duplex reflector and a single photon detector; wherein,

[0021] High repetition rate laser transmitter, used to transmit high repetition rate laser to space targets;

[0022] Fiber optic splitter, used to split optical signals into multiple paths;

[0023] a duplex reflector, disposed on the transmission light path of the second reflector, for transmitting the high repetition rate laser and reflecting the reflected laser from the space target to the single photon detector;

[0024] Single-photon detector, used to record the emission time of high-repetition-rate laser and the reception time of reflected laser, and obtain the distance information of space target through the information processing subsystem;

[0025] The laser phased-control super-resolution imaging subsystem includes an optical fiber array, a multimode interference beam splitter, a drive controller, a phase shifter, a grating diffraction array output end, a polarizer, a filter, an imaging lens, and a planar array detector. The optical fiber array, the multimode interference beam splitter, the drive controller, the phase shifter, and the grating diffraction array output end are sequentially arranged on the incident light path, and the optical fiber array is connected to the optical fiber beam splitter.

[0026] Fiber array, used to couple laser beams into optical waveguides to achieve beam transmission and distribution;

[0027] Multimode interference beam splitter, used to split the light beam in the optical waveguide into multiple paths, providing the basis for subsequent phase modulation and beam superposition;

[0028] The drive controller is used to drive and control the phase shifter, the output end of the grating diffraction array, the galvanometer and the optical fiber array to achieve precise control and scanning of the light beam;

[0029] Phase shifters are used to generate phase differences between optical waveguide array elements and control the propagation direction of the light beam by changing its phase;

[0030] The output end of the grating diffraction array is used to adjust the direction and angle of the light beam to achieve coherent superposition of the light beams and output the diffraction main maximum at a certain angle to point to the space target;

[0031] The output end of the grating diffraction array is connected to the galvanometer, and the output beam of the grating diffraction array is coupled into the optical fiber, which transmits the beam to the galvanometer through the optical fiber. When the beam reaches the galvanometer, the angle of the galvanometer is precisely controlled to achieve fast and flexible adjustment of the beam direction, thereby achieving precise positioning of the target.

[0032] Polarizers are used to control and adjust the polarization state of light entering the imaging system, filter out unwanted polarization components, and improve the contrast and quality of imaging;

[0033] Filters are used to filter out background light outside the working spectrum, effectively suppressing light of other wavelengths from entering the imaging system, improving the signal-to-noise ratio, and ensuring the clarity and accuracy of imaging;

[0034] The imaging lens is used to receive the light signal processed by the polarizer and filter and focus it on the area array detector to form an initial low-resolution image;

[0035] The area array detector is used to receive light signals processed by polarizers, filters and imaging lenses, and convert the received light signals into electrical signals to form a low-resolution image.

[0036] Furthermore, it also includes a card-type telescopic optical antenna, wherein:

[0037] The cassette telescopic optical antenna is installed on the detection and tracking turntable. The cassette telescopic optical antenna is the optical path part shared by the precision tracking detection subsystem, target ranging subsystem and laser phased control super-resolution imaging subsystem. The cassette telescopic optical antenna is used to increase the optical receiving and transmitting aperture, thereby collecting more target information detection energy and reducing the ranging laser divergence angle to achieve long-distance detection and ranging.

[0038] Furthermore, the target survey subsystem includes an optical unit and a detector, wherein:

[0039] An optical unit is used to receive sunlight reflected from a space target and focus the energy of the sunlight reflected from the space target onto the target surface of the detector;

[0040] The detector is used to convert the energy received by the target surface into electrons, thereby obtaining information about the space target.

[0041] Furthermore, the information processing subsystem is used to determine the position coordinates of the space target based on its own current posture, the orientation of the detection and tracking turntable, and the position of the space target information on the detector target surface.

[0042] Furthermore, the fine tracking detection subsystem includes a galvanometer, a reflector, a first spectroscope, a second spectroscope, a filter and a fine tracking detector;

[0043] The galvanometer receives the reflected light beam from the space target and reflects it to the first beam splitter through the reflector;

[0044] a first beam splitter, configured to reflect a portion of the reflected light beam of the space target to the laser phased super-resolution imaging subsystem, and transmit another portion of the reflected light beam of the space target to the second beam splitter;

[0045] a second beam splitter, configured to transmit a portion of the light beam transmitted through the first beam splitter to a target ranging subsystem, and reflect another portion of the light beam transmitted through the first beam splitter to a filter and perform high-frequency imaging on a fine tracking detector;

[0046] The fine tracking detector is connected to the galvanometer, and the fine tracking detector is used to control the galvanometer according to the imaging result of the fine tracking detector to achieve fine tracking of the space target.

[0047] Furthermore, the precision tracking subsystem also includes a collimator, which is used to convert the divergent light beam emitted by the laser into a parallel light beam, ensuring that the laser energy is concentratedly transmitted to subsequent optical components, while suppressing the beam diffusion angle, so that the laser can accurately form a diffraction main maximum beam after phase modulation, thereby improving the positioning accuracy of long-distance target irradiation.

[0048] Furthermore, the fine tracking subsystem also includes a switchable phase plate, which is used for dynamic wavefront modulation to compensate for wavefront distortion caused by spatial atmospheric turbulence or system aberrations, thereby ensuring beam coherence.

[0049] Furthermore, it also includes an electronically controlled auxiliary subsystem, which includes an optical axis capture unit, a coarse tracking unit and a fine tracking unit. The optical axis capture unit is used to complete the pointing of the optical axis and the capture of the space target under the guidance of an external guidance signal; the coarse tracking unit is used to track the target in the full range to ensure that the target is introduced into the fine tracking field of view; the fine tracking unit is used to quickly and accurately track the target within the fine tracking field of view to ensure accurate alignment of the space target.

[0050] A detection method using the above-mentioned active space target super-resolution detection system comprises the following steps:

[0051] Step 1: The master control subsystem controls the startup of each subsystem and supplies power to the hardware of each subsystem. Each subsystem enters the self-test state. After the self-test is completed, the system starts to work normally.

[0052] Step 2: The target survey subsystem detects the initial orbit and position information of the target, determines the spatial range of the detected target, and controls the tracking turntable to point to the target to achieve coarse tracking of the target;

[0053] Step 3: Split the high-repetition-rate laser beam using a fiber beam splitter, and modulate and scan the beam using an optical phased array, ultimately pointing it toward the space target.

[0054] Step 4: Collect target reflection information and use a precision tracking detector to perform high-frequency imaging of the target. At the same time, control the galvanometer mirror so that it is connected to the precision tracking detector and the output end of the laser phased array grating diffraction array respectively to ensure that the target is continuously located in the center of the field of view, achieving stable precision tracking;

[0055] Step 5: Based on the precise tracking imaging, the laser phased array super-resolution imaging subsystem is used to detect and image the target, and simultaneously obtain the target shape, size, and material information;

[0056] Step 6: Send a ranging laser pulse signal to the target, receive the laser ranging echo signal reflected by the target, calculate the target distance information based on the time difference, and complete the laser ranging;

[0057] Step 7: Input the acquired target position information, distance information, and multi-dimensional low-resolution image information into the information processing subsystem for synthetic aperture fusion processing, thereby realizing super-resolution imaging target feature recognition; and display the processed data on the display screen and feed it back to the master control subsystem at the same time.

[0058] Furthermore, the number of low-resolution image frames N required to achieve a specific super-resolution magnification M is determined by the super-resolution magnification M, the optical imaging unit aperture D, and the single spectrum movement step S, ensuring that the entire spectrum range is covered to achieve high-resolution image reconstruction;

[0059] Each time the beam pointing angle is moved, the spectrum shifts. By covering the spectrum range of M×D with a sufficient number of frames and combining the spectrum overlap rate, the convergence of the iterative process is ensured.

[0060] Therefore, the number of acquisition frames N is

[0061]

[0062] M is the super-resolution factor, that is, the resolution improvement factor expected to be achieved through super-resolution reconstruction;

[0063] D is the aperture of the optical imaging unit;

[0064] S is the single movement step of the spectrum, that is, the displacement of the spectrum at each movement;

[0065] And according to the number of acquisition frames N, it is ensured that there is sufficient overlap between adjacent spectra, so that the spectrum information can be effectively spliced ​​in the subsequent iteration process to achieve high-resolution image reconstruction;

[0066] By comparing the resolution of the low-resolution image and the super-resolution reconstructed image, the super-resolution ratio is quantified and the actual super-resolution ratio M of active coherent optical synthetic aperture super-resolution imaging is calculated. r ,

[0067] According to the actual super-resolution ratio M r The formula can be calculated

[0068] M r =W lr / W sr

[0069] W lr is the average value of the minimum resolvable line width in the low-resolution image,

[0070] W sr is the minimum resolvable linewidth in the image obtained by the Fourier stack super-resolution reconstruction algorithm.

[0071] Compared with the prior art, the present invention has the following effects:

[0072] The system provided by this invention can achieve high-resolution imaging while using a large-pixel detector. This is achieved by increasing the receiving area of ​​each detector pixel to capture more light energy. Using a laser phased-control super-resolution imaging subsystem and an information processing subsystem, synthetic aperture fusion processing is performed on low-resolution images to achieve super-resolution target feature recognition. This maximizes the ability to identify target details, thus resolving the problem of centimeter-level targets being dim, weak, and difficult to detect and identify.

[0073] Compared with existing technologies, the active space target super-resolution detection system of the present invention has significant advantages in the detection of dim targets and the tracking accuracy of moving targets, providing a better solution for high-precision detection of space debris. Specifically:

[0074] In terms of detection methods, the present invention adopts active detection technology. Compared with the passive detection method adopted by traditional methods that uses the target to reflect sunlight, active detection can obtain target information in more cases, does not rely on the reflection of sunlight, has a wider range of applications, and is more suitable for working effectively when the target itself does not emit light or the reflected light is weak.

[0075] To ensure target tracking accuracy, the system utilizes closed-loop galvanometer control in conjunction with a laser phased array. Real-time galvanometer control based on high-frequency imaging ensures the target remains centered in the field of view, effectively offsetting positional changes caused by target motion and maintaining high-precision tracking. Compared to traditional tracking methods, this system avoids issues such as turntable tracking lag and mechanical delay deviation, making it more suitable for centimeter-level, high-speed space debris detection.

[0076] In summary, the present invention solves the fundamental limitations of super-resolution imaging methods in terms of dark target detection, high-speed motion compensation, long-distance resolution and full-time domain working capabilities through improvements in active detection, dynamic environment adaptability, pixel size optimization and multi-dimensional information fusion, providing a new solution for centimeter-level precise monitoring of space debris. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 This is a functional module diagram of the active space target super-resolution detection system of the present invention;

[0078] Figure 2 Schematic diagram of the working process of the active space target super-resolution detection system of the present invention;

[0079] Figure 3 Schematic diagram of the system composition of the active space target super-resolution detection system of the present invention. DETAILED DESCRIPTION

[0080] Specific implementation method 1: Combination Figures 1 to 3This embodiment is explained, and the technical solutions in the embodiment of the present invention are clearly and completely described. Obviously, the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0081] It should be noted that the descriptions of the present invention regarding directions such as "front", "back", "left", "right", "inside", "outside", "left side", "right side", "upper", "lower", "top", and "bottom" are all defined based on the relationship between the orientations or positions shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure must be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0082] In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0083] An active space target super-resolution detection system includes a target survey subsystem, a precision tracking detection subsystem, a target ranging subsystem, a laser phased control super-resolution imaging subsystem, an information processing subsystem, a tracking turntable subsystem and a master control subsystem, wherein:

[0084] The target survey subsystem is installed on the detection and tracking turntable. It is used to achieve long-distance detection of space targets using a high-sensitivity optical detection unit and obtain the position coordinates of the space targets through the information processing subsystem.

[0085] The precision tracking detection subsystem is used to perform high-frequency imaging of space targets using precision tracking detectors. It also controls the galvanometer based on the high-frequency imaging to ensure that the space target remains in the center of the field of view, achieving stable precision tracking.

[0086] The target ranging subsystem is used to achieve long-distance and high-precision ranging of space targets using laser ranging technology, and obtain the distance information of space targets through the information processing subsystem;

[0087] The laser phased array super-resolution imaging subsystem is used to scan and modulate the laser beam to achieve spectral and polarization multi-dimensional detection and imaging of space targets, and the information processing subsystem is used to achieve image super-resolution reconstruction and attribute recognition of space targets;

[0088] The information processing subsystem is used to synthesize multiple low-resolution images into a high-resolution image using synthetic aperture technology and super-resolution reconstruction algorithms through an integrated high-speed processing chip, and to calculate the position coordinates of space targets, the ranging information of space targets, and the attributes of space targets;

[0089] The tracking turntable subsystem is used to control the detection and tracking turntable according to the position coordinates of the space target to achieve tracking of the space target;

[0090] The master control subsystem is used to control the hardware power supply switch and self-test work of each subsystem;

[0091] The target ranging subsystem includes a high repetition rate laser transmitter, an optical fiber beam splitter, a duplex reflector and a single photon detector; wherein,

[0092] High repetition rate laser transmitter, used to transmit high repetition rate laser to space targets;

[0093] Fiber optic splitter, used to split optical signals into multiple paths;

[0094] a duplex reflector, disposed on the transmission light path of the second reflector, for transmitting the high repetition rate laser and reflecting the reflected laser from the space target to the single photon detector;

[0095] The single-photon detector is used to record the emission time of the high-repetition-rate laser and the reception time of the reflected laser, and the distance information of the space target is obtained through the information processing subsystem. The working process of the target ranging subsystem is as follows:

[0096] 1) The information processing subsystem calculates the spatial target position information detected by the survey subsystem and performs preliminary orbit determination and positioning of the target;

[0097] 2) After the orbit position information is input into the target ranging subsystem, the target ranging subsystem drives the tracking turntable subsystem to track according to the predetermined orbit;

[0098] 3) The precision tracking detector realizes precise tracking and alignment of the target, the laser emits laser pulses, and at the same time triggers the timing unit to start timing;

[0099] 4) The single-photon detector receives the reflected signal from the target and sends it to the timing unit to record a time difference;

[0100] 5) The computer uses the prior orbit information to extract valid data from multiple sets of time differences and obtains the distance information through calculation.

[0101] The laser phased-control super-resolution imaging subsystem includes an optical fiber array, a multimode interference beam splitter, a drive controller, a phase shifter, a grating diffraction array output end, a polarizer, a filter, an imaging lens, and a planar array detector. The optical fiber array, the multimode interference beam splitter, the drive controller, the phase shifter, and the grating diffraction array output end are sequentially arranged on the incident light path, and the optical fiber array is connected to the optical fiber beam splitter.

[0102] The optical fiber array is used to couple the laser beam into the optical waveguide to achieve beam transmission and distribution; it can effectively transmit the high-power, high-coherence near-infrared beam generated by the laser to subsequent optical components.

[0103] Multimode interference beam splitter, used to split the light beam in the optical waveguide into multiple paths, providing the basis for subsequent phase modulation and beam superposition;

[0104] The drive controller is used to drive and control the phase shifter, the output end of the grating diffraction array, the galvanometer and the optical fiber array to achieve precise control and scanning of the light beam;

[0105] Phase shifters are used to generate phase differences between optical waveguide array elements and control the propagation direction of the light beam by changing its phase;

[0106] The output of the grating diffraction array adjusts the direction and angle of the beams to achieve coherent superposition and output the diffraction principal maximum at a specific angle, directed toward a spatial target. The principal diffraction maximum refers to the diffraction order with the highest energy (usually the zeroth or first order) when light waves interfere and superimpose through the periodic structure. The specific angle is the deflection angle (θ) determined by phase modulation, satisfying the grating equation d sinθ = mλ (where d is the grating period, λ is the wavelength, and m is the diffraction order). Multiple beams passing through the grating diffraction array interfere with each other, forming constructive interference in a specific θ direction and destructive interference in other directions. More than 90% of the laser energy is concentrated in the direction of the principal maximum.

[0107] The output end of the grating diffraction array is connected to the galvanometer, and the output beam of the grating diffraction array is coupled into the optical fiber, which transmits the beam to the galvanometer through the optical fiber. When the beam reaches the galvanometer, the angle of the galvanometer is precisely controlled to achieve fast and flexible adjustment of the beam direction, thereby achieving precise positioning of the target.

[0108] Polarizers are used to control and adjust the polarization state of light entering the imaging system, filter out unwanted polarization components, and improve the contrast and quality of imaging;

[0109] Filters are used to filter out background light outside the working spectrum, effectively suppressing light of other wavelengths from entering the imaging system, improving the signal-to-noise ratio, and ensuring the clarity and accuracy of imaging;

[0110] The imaging lens is used to receive the light signal processed by the polarizer and filter and focus it on the area array detector to form an initial low-resolution image;

[0111] The area array detector is used to receive light signals processed by polarizers, filters and imaging lenses, and convert the received light signals into electrical signals to form a low-resolution image.

[0112] The present invention provides an active space target super-resolution detection system. The target survey subsystem utilizes a high-sensitivity optical detection unit to achieve long-range detection of space targets, and the information processing subsystem calculates the position coordinates of the space targets. Based on coarse tracking, the fine tracking detection subsystem uses a fine tracking detector to perform high-frequency imaging of the space target. Simultaneously, the galvanometer is controlled based on the high-frequency imaging to ensure that the space target remains in the center of the field of view, achieving stable fine tracking. The target ranging subsystem utilizes laser ranging technology to achieve long-range, high-precision ranging of the space target, and the information processing subsystem calculates the distance information of the space target. The laser phased control super-resolution imaging subsystem scans and modulates the light beam to achieve detection and imaging of the space target, and the information processing subsystem performs super-resolution image reconstruction and space target attribute identification. The laser phased control super-resolution imaging subsystem detects and acquires a series of images, and then uses the information processing subsystem algorithm and synthetic aperture stitching method to calculate the specific super-resolution magnification and effect. The master control subsystem is used to control the hardware power supply and self-test functions of each subsystem.

[0113] The system provided by this invention can achieve high-resolution imaging while using a large-pixel detector. This is achieved by increasing the receiving area of ​​each detector pixel to capture more light energy. The laser phased-control super-resolution imaging subsystem and the information processing subsystem perform synthetic aperture fusion processing on low-resolution images, enabling super-resolution imaging and target feature recognition. This maximizes the ability to discern target details, thus resolving the problem of centimeter-level targets being dim, small, and difficult to detect and identify. This provides a new direction for the safe operation of spacecraft and the sustainable use of the space environment.

[0114] Compared with existing technologies, the active space target super-resolution detection system of the present invention has significant advantages in dim target detection, moving target tracking accuracy, and super-resolution imaging methods, providing a more optimal solution for high-precision detection of space debris. Specifically:

[0115] In terms of detection, the present invention employs active detection technology, in which a laser combined with an optical phased array actively emits a coherent beam to illuminate the target (the optical phased array comprises a fiber array, a multimode interference beam splitter, a drive controller, a phase shifter, and a grating diffraction array output). The laser provides the light source, while the optical phased array achieves beam scanning and pointing control through phase modulation, directly enhancing the intensity of the target's reflected signal. A light source scanning mode (not camera scanning) is selected, and the optical phased array dynamically adjusts the beam direction to avoid frequent payload maneuvers. Compared to traditional passive detection methods that rely solely on sunlight reflected from the target without an active illumination source, active detection can acquire target information in more situations, is independent of sunlight reflection, and has a wider range of applications. It is also more suitable for working effectively even when the target itself is non-luminous or the reflected light is weak.

[0116] To ensure target tracking accuracy, the system utilizes closed-loop galvanometer control in conjunction with a laser phased array. Real-time galvanometer control based on high-frequency imaging ensures the target remains centered in the field of view. Direct compensation via the galvanometer effectively offsets positional changes caused by target motion, maintaining high-precision tracking. This secondary application of the galvanometer acts as a dual correction. Compared to traditional tracking methods, it avoids issues such as turntable tracking lag and mechanical delay deviation, making it more suitable for centimeter-level, high-speed space debris detection.

[0117] In summary, the present invention solves the fundamental limitations of super-resolution imaging methods in terms of dark target detection, high-speed motion compensation, long-distance resolution and full-time domain working capabilities through improvements in active detection, dynamic environment adaptability, pixel size optimization and multi-dimensional information fusion, providing a new solution for centimeter-level precise monitoring of space debris.

[0118] Also included is a card-type telescopic optical antenna, wherein:

[0119] The cassette telescopic optical antenna is installed on the detection and tracking turntable. The cassette telescopic optical antenna is the optical path part shared by the precision tracking detection subsystem, target ranging subsystem and laser phased control super-resolution imaging subsystem. The cassette telescopic optical antenna is used to increase the optical receiving and transmitting aperture, thereby collecting more target information detection energy and reducing the ranging laser divergence angle to achieve long-distance detection and ranging.

[0120] The target survey subsystem includes an optical unit and a detector, wherein:

[0121] An optical unit is used to receive sunlight reflected from a space target and focus the energy of the sunlight reflected from the space target onto the target surface of the detector;

[0122] The detector is used to convert the energy received by the target surface into electrons, thereby obtaining information about the space target.

[0123] The target survey subsystem primarily performs staring imaging of space targets, combines this with a turntable for wide-field scanning, and detects targets by receiving sunlight reflected from them. Furthermore, the subsystem determines the initial coordinates of the target based on the platform's posture, the orientation of the optical axis, and the target's position within the image plane. The entire subsystem must be lightweight and compact.

[0124] The specific workflow of the target census subsystem is as follows:

[0125] a) The energy of sunlight reflected by the target is focused on the detector surface through the optical system, and the received photons are converted into electrons, thereby obtaining target information and detecting the target; large-scale detection is achieved through swing scanning;

[0126] b) Determine the initial position of the target based on the satellite attitude, turntable pointing, and the position of the target signal on the detector target surface, and extract the target signal from the background through the processing subsystem;

[0127] c) Input the extracted target information into the tracking turntable subsystem, control the tracking turntable pointing, ensure that the target is continuously in the field of view of the survey subsystem, and realize continuous monitoring of space targets;

[0128] d) Track the target trajectory and complete the positioning of the target by combining the laser ranging information.

[0129] The information processing subsystem is used to determine the position coordinates of the space target based on its own current posture, the direction of the detection and tracking turntable, and the position of the space target information on the detector target surface.

[0130] The fine tracking detection subsystem includes a galvanometer, a reflector, a first spectroscope, a second spectroscope, a filter and a fine tracking detector;

[0131] The galvanometer receives the reflected light beam from the space target and reflects it to the first beam splitter through the reflector;

[0132] a first beam splitter, configured to reflect a portion of the reflected light beam of the space target to the laser phased super-resolution imaging subsystem, and transmit another portion of the reflected light beam of the space target to the second beam splitter;

[0133] a second beam splitter, configured to transmit a portion of the light beam transmitted through the first beam splitter to a target ranging subsystem, and reflect another portion of the light beam transmitted through the first beam splitter to a filter and perform high-frequency imaging on a fine tracking detector;

[0134] The fine tracking detector is connected to the galvanometer, and the fine tracking detector is used to control the galvanometer according to the imaging result of the fine tracking detector to achieve fine tracking of the space target.

[0135] The precision tracking subsystem also includes a collimator, which is used to convert the divergent light beam emitted by the laser into a parallel light beam, ensuring that the laser energy is concentratedly transmitted to subsequent optical components, while suppressing the beam diffusion angle so that the laser can accurately form a diffraction main maximum beam after phase modulation, thereby improving the positioning accuracy of long-distance target irradiation.

[0136] The fine tracking subsystem also includes a switchable phase plate, which is used for dynamic wavefront modulation to compensate for wavefront distortion caused by spatial atmospheric turbulence or system aberrations and ensure beam coherence.

[0137] It also includes an electronically controlled auxiliary subsystem, which includes an optical axis capture unit, a coarse tracking unit and a fine tracking unit. The optical axis capture unit is used to complete the pointing of the optical axis and the capture of the space target under the guidance of an external guidance signal; the coarse tracking unit is used to track the target in the full range to ensure that the target is introduced into the fine tracking field of view; the fine tracking unit is used to quickly and accurately track the target within the fine tracking field of view to ensure accurate alignment of the space target.

[0138] A detection method using the above-mentioned active space target super-resolution detection system comprises the following steps:

[0139] Step 1: The master control subsystem controls the startup of each subsystem and supplies power to the hardware of each subsystem. Each subsystem enters the self-test state. After the self-test is completed, the system starts to work normally.

[0140] Step 2: The target survey subsystem detects the initial orbit and position information of the target, determines the spatial range of the detected target, and controls the tracking turntable to point to the target to achieve coarse tracking of the target;

[0141] Step 3: Split the high-repetition-rate laser beam using a fiber beam splitter, and modulate and scan the beam using an optical phased array, ultimately pointing it toward the space target.

[0142] Step 4: Collect target reflection information and use a precision tracking detector to perform high-frequency imaging of the target. At the same time, control the galvanometer mirror so that it is connected to the precision tracking detector and the output end of the laser phased array grating diffraction array respectively to ensure that the target is continuously located in the center of the field of view, achieving stable precision tracking;

[0143] Step 5: Based on the precise tracking imaging, the laser phased array super-resolution imaging subsystem is used to detect and image the target, and simultaneously obtain the target shape, size, and material information;

[0144] Step 6: Send a ranging laser pulse signal to the target, receive the laser ranging echo signal reflected by the target, calculate the target distance information based on the time difference, and complete the laser ranging;

[0145] Step 7: Input the acquired target position information, distance information, and multi-dimensional low-resolution image information into the information processing subsystem for synthetic aperture fusion processing, thereby realizing super-resolution imaging target feature recognition; and display the processed data on the display screen and feed it back to the master control subsystem at the same time.

[0146] The number of low-resolution image frames N required to achieve a specific super-resolution magnification M is determined by the super-resolution magnification M, the optical imaging unit aperture D, and the single spectrum movement step S to ensure that the entire spectrum range is covered to achieve high-resolution image reconstruction;

[0147] Each time the beam pointing angle is moved, the spectrum shifts. By covering the spectrum range of M×D with a sufficient number of frames and combining the spectrum overlap rate, the convergence of the iterative process is ensured.

[0148] Therefore, the number of acquisition frames N is

[0149]

[0150] M is the super-resolution factor, that is, the resolution improvement factor expected to be achieved through super-resolution reconstruction;

[0151] D is the aperture (physical size) of the optical imaging unit;

[0152] S is the single movement step of the spectrum, that is, the displacement of the spectrum at each movement;

[0153] And according to the number of acquisition frames N, it is ensured that there is sufficient overlap between adjacent spectra, so that the spectrum information can be effectively spliced ​​in the subsequent iteration process to achieve high-resolution image reconstruction;

[0154] By comparing the resolution of the low-resolution image and the super-resolution reconstructed image, the super-resolution ratio is quantified and the actual super-resolution ratio M of active coherent optical synthetic aperture super-resolution imaging is calculated. r ,

[0155] According to the actual super-resolution ratio M r The formula can be calculated

[0156] M r =W lr / W sr

[0157] W lr is the average value of the minimum resolvable line width in the low-resolution image,

[0158] W sr is the minimum resolvable linewidth in the image obtained by the Fourier stack super-resolution reconstruction algorithm.

[0159] In super-resolution imaging, synthetic aperture technology and super-resolution reconstruction algorithms are used to directly fuse multiple frames, overcoming the limitations of detector pixel size and performing calculations with a quantifiable number of algorithm frames. Compared to compressed sensing reconstruction, which relies on initial conditions and sparsity, synthetic aperture technology has a stronger ability to identify target features and higher resolution.

[0160] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An active space target super-resolution detection system, characterized by: It includes target survey subsystem, precision tracking detection subsystem, target ranging subsystem, laser phased array super-resolution imaging subsystem, information processing subsystem, tracking turntable subsystem and general control subsystem, among which, The target survey subsystem is installed on the detection and tracking turntable. It is used to achieve long-distance detection of space targets using a high-sensitivity optical detection unit and obtain the position coordinates of the space targets through the information processing subsystem. The precision tracking detection subsystem is used to perform high-frequency imaging of space targets using precision tracking detectors. It also controls the galvanometer based on the high-frequency imaging to ensure that the space target remains in the center of the field of view, achieving stable precision tracking. The target ranging subsystem is used to achieve long-distance and high-precision ranging of space targets using laser ranging technology, and obtain the distance information of space targets through the information processing subsystem; The laser phased array super-resolution imaging subsystem is used to scan and modulate the laser beam to achieve spectral and polarization multi-dimensional detection and imaging of space targets, and the information processing subsystem is used to achieve image super-resolution reconstruction and attribute recognition of space targets; The information processing subsystem is used to synthesize multiple low-resolution images into a high-resolution image using synthetic aperture technology and super-resolution reconstruction algorithms through an integrated high-speed processing chip, and to calculate the position coordinates of space targets, the ranging information of space targets, and the attributes of space targets; The tracking turntable subsystem is used to control the detection and tracking turntable according to the position coordinates of the space target to achieve tracking of the space target; The master control subsystem is used to control the hardware power supply switch and self-test work of each subsystem; The target ranging subsystem includes a high repetition rate laser transmitter, an optical fiber beam splitter, a duplex reflector and a single photon detector; wherein, High repetition rate laser transmitter, used to transmit high repetition rate laser to space targets; Fiber optic splitter, used to split optical signals into multiple paths; a duplex reflector, disposed on the transmission light path of the second reflector, for transmitting the high repetition rate laser and reflecting the reflected laser from the space target to the single photon detector; Single-photon detector, used to record the emission time of high-repetition-rate laser and the reception time of reflected laser, and obtain the distance information of space target through the information processing subsystem; The laser phased-control super-resolution imaging subsystem includes an optical fiber array, a multimode interference beam splitter, a drive controller, a phase shifter, a grating diffraction array output end, a polarizer, a filter, an imaging lens, and a planar array detector. The optical fiber array, the multimode interference beam splitter, the drive controller, the phase shifter, and the grating diffraction array output end are sequentially arranged on the incident light path, and the optical fiber array is connected to the optical fiber beam splitter. Fiber array, used to couple laser beams into optical waveguides to achieve beam transmission and distribution; Multimode interference beam splitter, used to split the light beam in the optical waveguide into multiple paths, providing the basis for subsequent phase modulation and beam superposition; The drive controller is used to drive and control the phase shifter, the output end of the grating diffraction array, the galvanometer and the optical fiber array to achieve precise control and scanning of the light beam; Phase shifters are used to generate phase differences between optical waveguide array elements and control the propagation direction of the light beam by changing its phase; The output end of the grating diffraction array is used to adjust the direction and angle of the light beam to achieve coherent superposition of the light beams and output the diffraction main maximum at a certain angle to point to the space target; The output end of the grating diffraction array is connected to the galvanometer, and the output beam of the grating diffraction array is coupled into the optical fiber, which transmits the beam to the galvanometer through the optical fiber. When the beam reaches the galvanometer, the angle of the galvanometer is precisely controlled to achieve fast and flexible adjustment of the beam direction, thereby achieving precise positioning of the target. Polarizers are used to control and adjust the polarization state of light entering the imaging system, filter out unwanted polarization components, and improve the contrast and quality of imaging; Filters are used to filter out background light outside the working spectrum, effectively suppressing light of other wavelengths from entering the imaging system, improving the signal-to-noise ratio, and ensuring the clarity and accuracy of imaging; The imaging lens is used to receive the light signal processed by the polarizer and filter and focus it on the area array detector to form an initial low-resolution image; The area array detector is used to receive light signals processed by polarizers, filters and imaging lenses, and convert the received light signals into electrical signals to form a low-resolution image.

2. The active space target super-resolution detection system according to claim 1, characterized in that: Also included is a card-type telescopic optical antenna, wherein: The cassette telescopic optical antenna is installed on the detection and tracking turntable. The cassette telescopic optical antenna is the optical path part shared by the precision tracking detection subsystem, target ranging subsystem and laser phased control super-resolution imaging subsystem. The cassette telescopic optical antenna is used to increase the optical receiving and transmitting aperture, thereby collecting more target information detection energy and reducing the ranging laser divergence angle to achieve long-distance detection and ranging.

3. The active space target super-resolution detection system according to claim 1, characterized in that: The target survey subsystem includes an optical unit and a detector, wherein: An optical unit is used to receive sunlight reflected from a space target and focus the energy of the sunlight reflected from the space target onto the target surface of the detector; The detector is used to convert the energy received by the target surface into electrons, thereby obtaining information about the space target.

4. The active space target super-resolution detection system according to claim 1, characterized in that: The information processing subsystem is used to determine the position coordinates of the space target based on its own current posture, the direction of the detection and tracking turntable, and the position of the space target information on the detector target surface.

5. The active space target super-resolution detection system according to claim 1, characterized in that: The fine tracking detection subsystem includes a galvanometer, a reflector, a first spectroscope, a second spectroscope, a filter and a fine tracking detector; The galvanometer receives the reflected light beam from the space target and reflects it to the first beam splitter through the reflector; a first beam splitter, configured to reflect a portion of the reflected light beam of the space target to the laser phased super-resolution imaging subsystem, and transmit another portion of the reflected light beam of the space target to the second beam splitter; a second beam splitter, configured to transmit a portion of the light beam transmitted through the first beam splitter to a target ranging subsystem, and reflect another portion of the light beam transmitted through the first beam splitter to a filter and perform high-frequency imaging on a fine tracking detector; The fine tracking detector is connected to the galvanometer, and the fine tracking detector is used to control the galvanometer according to the imaging result of the fine tracking detector to achieve fine tracking of the space target.

6. The active space target super-resolution detection system according to claim 5, characterized in that: The precision tracking subsystem also includes a collimator, which is used to convert the divergent light beam emitted by the laser into a parallel light beam, ensuring that the laser energy is concentratedly transmitted to subsequent optical components, while suppressing the beam diffusion angle so that the laser can accurately form a diffraction main maximum beam after phase modulation, thereby improving the positioning accuracy of long-distance target irradiation.

7. The active space target super-resolution detection system according to claim 6, characterized in that: The fine tracking subsystem also includes a switchable phase plate, which is used for dynamic wavefront modulation to compensate for wavefront distortion caused by spatial atmospheric turbulence or system aberrations and ensure beam coherence.

8. The active space target super-resolution detection system according to claim 1, characterized in that: It also includes an electronically controlled auxiliary subsystem, which includes an optical axis capture unit, a coarse tracking unit and a fine tracking unit. The optical axis capture unit is used to complete the pointing of the optical axis and the capture of the space target under the guidance of an external guidance signal; the coarse tracking unit is used to track the target in the full range to ensure that the target is introduced into the fine tracking field of view; the fine tracking unit is used to quickly and accurately track the target within the fine tracking field of view to ensure accurate alignment of the space target.

9. A detection method using the active space target super-resolution detection system according to any one of claims 1 to 8, comprising the following steps: Step 1: The master control subsystem controls the startup of each subsystem and supplies power to the hardware of each subsystem. Each subsystem enters the self-test state. After the self-test is completed, the system starts to work normally. Step 2: The target survey subsystem detects the initial orbit and position information of the target, determines the spatial range of the detected target, and controls the tracking turntable to point to the target to achieve coarse tracking of the target; Step 3: Split the high-repetition-rate laser beam using a fiber beam splitter, and modulate and scan the beam using an optical phased array, ultimately pointing it toward the space target. Step 4: Collect target reflection information and use a precision tracking detector to perform high-frequency imaging of the target. At the same time, control the galvanometer mirror so that it is connected to the precision tracking detector and the output end of the laser phased array grating diffraction array respectively to ensure that the target is continuously located in the center of the field of view, achieving stable precision tracking; Step 5: Based on the precise tracking imaging, the laser phased array super-resolution imaging subsystem is used to detect and image the target, and simultaneously obtain the target shape, size, and material information; Step 6: Send a ranging laser pulse signal to the target, receive the laser ranging echo signal reflected by the target, calculate the target distance information based on the time difference, and complete the laser ranging; Step 7: Input the acquired target position information, distance information, and multi-dimensional low-resolution image information into the information processing subsystem for synthetic aperture fusion processing, thereby realizing super-resolution imaging target feature recognition; and display the processed data on the display screen and feed it back to the master control subsystem at the same time.

10. The detection method according to claim 9, characterized in that: The number of low-resolution image frames N required to achieve a specific super-resolution magnification M is determined by the super-resolution magnification M, the optical imaging unit aperture D, and the single spectrum movement step S to ensure that the entire spectrum range is covered to achieve high-resolution image reconstruction; Each time the beam pointing angle is moved, the spectrum shifts. By covering the spectrum range of M×D with a sufficient number of frames and combining the spectrum overlap rate, the convergence of the iterative process is ensured. Therefore, the number of acquisition frames N is M is the super-resolution factor, that is, the resolution improvement factor expected to be achieved through super-resolution reconstruction; D is the aperture of the optical imaging unit; S is the single movement step of the spectrum, that is, the displacement of the spectrum at each movement; And according to the number of acquisition frames N, it is ensured that there is sufficient overlap between adjacent spectra, so that the spectrum information can be effectively spliced ​​in the subsequent iteration process to achieve high-resolution image reconstruction; By comparing the resolution of the low-resolution image and the super-resolution reconstructed image, the super-resolution ratio is quantified and the actual super-resolution ratio M of active coherent optical synthetic aperture super-resolution imaging is calculated. r , According to the actual super-resolution ratio M r The formula can be calculated M r =W lr / W sr W lr is the average value of the minimum resolvable line width in the low-resolution image, W sr is the minimum resolvable linewidth in the image obtained by the Fourier stack super-resolution reconstruction algorithm.

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