An integrated system for super-resolution imaging and ranging communication of space-based space targets

Abstract

The present application discloses an integrated system of space-based space target super-resolution imaging and ranging communication, which relates to the field of space target detection technology. In the system, a high-sensitivity optical detection unit is used to realize long-distance detection of space targets; on the basis of coarse tracking, a fine tracking detector is used to perform high-frequency imaging of the space target, and the galvanometer is controlled according to the high-frequency imaging to realize stable fine tracking; laser ranging technology is also used to realize long-distance high-precision ranging of the space target, and in addition, a multi-dimensional super-diffraction sub-pixel imaging subsystem is used to realize spectral and polarization multi-dimensional detection imaging of the space target, so as to realize the attribute recognition of the space target; laser communication can also be used to realize the positioning and tracking of the communication target and the transmission of information; the system provided by the present application can simultaneously realize diffraction super-resolution and sub-pixel super-resolution, and maximize the recognition ability of the target details, thereby solving the problem that centimeter-level targets are dark, weak and small, and difficult to detect and identify.

Description

Technical Field

[0001] The present application relates to the technical field of space target detection, and in particular to an integrated system of space-based space target super-resolution imaging and ranging communication. Background Art

[0002] With the development of aerospace technology, a large number of debris have been generated in space, including abandoned satellites, explosions or collisions of spacecraft batteries and fuel tanks, the last stage of launch vehicles, ejecta of solid rocket engines, and discarded objects during space missions. Most of them are distributed in the most frequently used low earth orbit (LEO) 2000km above the ground, and a small part is in the geosynchronous orbit (GEO) 35876km above the ground. Among them, space debris with a size of 1cm-10cm is currently difficult to track, catalog, monitor and warn, and lacks reasonable protection measures. It is recognized by the international community as the debris that poses the greatest threat to spacecraft.

[0003] In recent years, the number of cases where satellites have been damaged or even failed by space debris has been increasing. These application satellites are closely related to the national economy and national defense construction. Once damaged, the social and economic impacts are huge, and even endanger national security. In general, future development trends have put forward higher requirements for the long life and high reliability of satellites, while the space debris environment has become increasingly harsh. The resulting contradictions require us to face the detection, protection and active removal of space debris, especially small-scale space debris in low-Earth orbit. Effective means need to be taken to achieve accurate detection, effective protection and efficient removal. If it is possible to achieve high-precision detection, orbit determination and positioning of small-scale space debris, and achieve a position error better than 100m-300m, it will enable on-orbit spacecraft to effectively avoid collisions with space debris or other spacecraft.

[0004] The main difficulties in space debris detection include:

[0005] (1) Weak target: This results in insufficient detection light energy, insufficient image signal-to-noise ratio and contrast, and difficulty in detecting dim targets.

[0006] (2) Target motion: This causes the target position to continuously change, resulting in poor image stability and intensity balance, making it difficult to detect moving targets.

[0007] (3) Small target size: This results in low target spatial resolution, high requirements for image recognition and extraction technology, and difficulty in detecting small targets.

[0008] Therefore, the above difficulties in space debris detection are major technical issues faced in building a space debris monitoring and early warning system, and further realizing the cataloging and removal of space debris. Summary of the invention

[0009] The purpose of this application is to provide an integrated system of space-based space target super-resolution imaging and ranging communication, which can realize the detection, positioning, orbit determination and information transmission of centimeter-level dim and small targets in space.

[0010] To achieve the above objectives, this application provides the following solutions:

[0011] A space-based space target super-resolution imaging and ranging communication integrated system includes: a target survey subsystem, a precision tracking and detection subsystem, a target ranging subsystem, a multi-dimensional super-diffraction sub-pixel imaging subsystem, an information transmission subsystem, an information processing subsystem, a tracking turntable subsystem and a master control subsystem.

[0012] The target survey subsystem is installed on the detection and tracking turntable. It is used to realize long-distance detection of space targets by using a high-sensitivity optical detection unit, and obtain the position coordinates of the space targets through the information processing subsystem.

[0013] The precision tracking detection subsystem is used to perform high-frequency imaging of space targets using precision tracking detectors, and at the same time control the galvanometer based on the high-frequency imaging to ensure that the space target is continuously located in the center of the field of view, thereby achieving stable precision tracking.

[0014] 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 calculation by the information processing subsystem.

[0015] The multi-dimensional super-diffraction sub-pixel imaging subsystem is used to realize spectral and polarization multi-dimensional detection imaging of space targets, and realize attribute recognition of space targets through the information processing subsystem.

[0016] The information transmission subsystem is arranged on the communication tracking turntable and is used to realize the positioning and tracking of the communication target by means of laser communication and to transmit the relevant information of the space target to the communication target.

[0017] The information processing subsystem is used to utilize integrated high-speed processing chips and information fusion algorithms to realize the calculation of the position coordinates of space targets, the calculation of the ranging information of space targets, and the identification of 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; it is also used to control the rotation of the communication tracking turntable according to the positioning of the communication target to achieve tracking of the communication target.

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

[0020] Optionally, it also includes: a card-type telescopic optical antenna.

[0021] The cassette-type telescopic optical antenna is installed on the detection and tracking turntable. The cassette-type telescopic optical antenna is the optical path part shared by the precision tracking detection subsystem, the target ranging subsystem and the multi-dimensional super-diffraction sub-pixel imaging subsystem. The cassette-type telescopic optical antenna is used to increase the optical receiving and transmitting aperture, so as to collect more target information detection energy and reduce the ranging laser divergence angle to achieve long-distance detection and ranging.

[0022] Optionally, the target survey subsystem includes: an optical unit and a detector.

[0023] The optical unit is used to receive the sunlight reflected from the space target and focus the energy of the sunlight reflected from the space target to the target surface of the detector.

[0024] The detector is used to convert the energy received by the target surface into electrons, thereby obtaining information about the space target.

[0025] The information processing subsystem is used to determine the position coordinates of the space target based on its current posture, the direction of the detection and tracking turntable, and the position of the space target's information on the detector target surface.

[0026] Optionally, the fine tracking detection subsystem includes: a first galvanometer, a first reflector, a first beam splitter group, a narrow-band filter, and a fine tracking detector; the first beam splitter group includes a first beam splitter and a second beam splitter.

[0027] The first galvanometer receives the reflected light beam from the space target and reflects it to the first beam splitter through the first reflector.

[0028] The first beam splitter is used to reflect a part of the reflected light beam of the space target to the multi-dimensional super-diffraction sub-pixel imaging subsystem, and transmit another part of the reflected light beam of the space target to the second beam splitter.

[0029] The second beam splitter is used to transmit a part of the light beam transmitted through the first beam splitter to the target ranging subsystem, and reflect another part of the light beam transmitted through the first beam splitter to the narrow band filter and perform high frequency imaging on the fine tracking detector.

[0030] The fine tracking detector is connected to the first galvanometer, and the fine tracking detector is used to control the first galvanometer according to the imaging result of the fine tracking detector to achieve fine tracking of the space target.

[0031] Optionally, the target ranging subsystem includes: a high repetition rate laser transmitter, a duplex reflector and a single photon detector.

[0032] A high repetition rate laser transmitter is used to transmit high repetition rate laser to a space target; a duplex reflector is arranged on the transmission light path of the second reflector, and is used to transmit the high repetition rate laser, and reflect the reflected laser from the space target to the single photon detector; 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 obtain the distance information of the space target through the information processing subsystem.

[0033] Optionally, the multi-dimensional super-diffraction sub-pixel imaging subsystem includes: a pupil filter, a front-end optical objective lens, a compressed sensing encoding plate, a relay lens group, a third beam splitter, a spectral detector and a polarization focal plane detector; the pupil filter, the front-end optical objective lens, the compressed sensing encoding plate, the relay lens group, the third beam splitter, the spectral detector and the polarization focal plane detector are sequentially arranged on the propagation optical path of the reflected light beam from the space target.

[0034] Pupil filter, used to modulate the wavefront to achieve super-diffraction resolution imaging.

[0035] The front optical objective lens is used to image the reflected light passing through the pupil filter at the intermediate image plane of the system.

[0036] The compressed sensing encoding board is arranged at the middle image plane of the system and is used for compressed sensing encoding of scene information.

[0037] The relay mirror group is used to project the primary image plane after the compressed sensing encoding onto the surface of the spectrum detector and the polarization focal plane detector respectively through the third beam splitter.

[0038] Optionally, the pupil filter is specifically a pure amplitude type, pure phase type or complex amplitude type annular zone filter; the annular zone on the surface of the pupil filter is designed by the following steps:

[0039] According to the sub-pixel super-resolution ratio of the compressed sensing encoding plate and the pixel size of the polarization focal plane detector, the actual equivalent pixel size is calculated.

[0040] The minimum diffraction super-resolution ratio is calculated based on the point spread function radius, optical wavelength, optical system F number, super-resolution ratio and actual equivalent pixel size.

[0041] The annular zone on the surface of the pupil filter is designed according to the minimum diffraction super-resolution magnification, and the modulation function of the pupil filter is changed to make the diffraction super-resolution magnification of the pupil filter greater than or equal to the minimum diffraction super-resolution magnification.

[0042] Optionally, the specific encoding form of the compressed sensing encoding board includes a random Gaussian matrix, a random Fourier transform matrix and a random Bernoulli matrix.

[0043] Optionally, a polarization focal plane detector combines polarization measurement technology and focal plane array technology, and can simultaneously obtain intensity information and polarization information of a target object, and can obtain sub-pixel super-resolution image information after reconstruction.

[0044] Optionally, it also includes: an electronically controlled auxiliary subsystem; the electronically controlled auxiliary subsystem 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 guide 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.

[0045] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0046] The present application provides an integrated system for super-resolution imaging and ranging communication of space-based space targets. The target survey subsystem uses a high-sensitivity optical detection unit to realize long-distance detection of space targets, and the information processing subsystem calculates the position coordinates of the space targets; on the basis of coarse tracking, the fine tracking detection subsystem uses a fine tracking detector to perform high-frequency imaging of the space target, and at the same time controls the galvanometer according to the high-frequency imaging to ensure that the space target is continuously located at the center of the field of view, thereby realizing stable fine tracking; the target ranging subsystem uses laser ranging technology to realize long-distance high-precision ranging of the space target, and the information processing subsystem calculates the distance information of the space target; the multi-dimensional super-diffraction sub-pixel imaging subsystem realizes spectral and polarization multi-dimensional detection imaging of the space target, and the information processing subsystem realizes attribute recognition of the space target; the information transmission subsystem uses laser communication to realize positioning and tracking of the communication target and transmits relevant information of the space target to the communication target; the general control subsystem is used to control the hardware power switch and self-test work of each subsystem. The system provided by the present application can ensure high-resolution imaging while using a large pixel detector, that is, by increasing the receiving area of ​​a single pixel of the detector, thereby obtaining more light energy; based on a multi-dimensional super-diffraction sub-pixel imaging subsystem, it simultaneously achieves diffraction super-resolution and sub-pixel super-resolution, maximizing the ability to identify target details, thereby solving the problem that centimeter-level targets are dark, weak, and difficult to detect and identify. It can also simultaneously obtain multi-dimensional (polarization, spectrum, intensity) information to obtain multiple characteristics of the target, thereby improving the detection rate and recognition rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A functional module diagram of a space-based space target super-resolution imaging and ranging communication integrated system provided in one embodiment of the present application.

[0049] Figure 2 A schematic diagram of the workflow of a space-based space target super-resolution imaging and ranging communication integrated system provided in one embodiment of the present application.

[0050] Figure 3 A functional module diagram of a space-based space target super-resolution imaging and ranging communication integrated system provided in another embodiment of the present application.

[0051] Figure 4 A schematic diagram of the workflow of a target survey subsystem in a space-based space target super-resolution imaging and ranging communication integrated system provided in another embodiment of the present application.

[0052] Figure 5 A schematic diagram of the optical path propagation of a multi-dimensional super-diffraction sub-pixel imaging subsystem in an integrated system of space-based space target super-resolution imaging and ranging communication provided in another embodiment of the present application. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0055] In an exemplary embodiment, Figure 1 The system block diagram shown provides an integrated system for space-based space target super-resolution imaging and ranging communication, including: a target survey subsystem, a precision tracking and detection subsystem, a target ranging subsystem, a multi-dimensional super-diffraction sub-pixel imaging subsystem, an information transmission subsystem, an information processing subsystem, a tracking turntable subsystem and a general control subsystem.

[0056] The target survey subsystem is installed on the detection and tracking turntable. It is used to realize long-distance detection of space targets by using a high-sensitivity optical detection unit, and obtain the position coordinates of the space targets through the information processing subsystem.

[0057] The precision tracking detection subsystem is used to perform high-frequency imaging of space targets using precision tracking detectors, and at the same time control the galvanometer based on the high-frequency imaging to ensure that the space target is continuously located in the center of the field of view, thereby achieving stable precision tracking.

[0058] 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 calculation by the information processing subsystem.

[0059] The multi-dimensional super-diffraction sub-pixel imaging subsystem is used to realize spectral and polarization multi-dimensional detection imaging of space targets, and realize attribute recognition of space targets through the information processing subsystem.

[0060] The information transmission subsystem is arranged on the communication tracking turntable and is used to realize the positioning and tracking of the communication target by means of laser communication and to transmit the relevant information of the space target to the communication target.

[0061] The information processing subsystem is used to utilize integrated high-speed processing chips and information fusion algorithms to realize the calculation of the position coordinates of space targets, the calculation of the ranging information of space targets, and the identification of the attributes of space targets.

[0062] 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; it is also used to control the rotation of the communication tracking turntable according to the positioning of the communication target to achieve tracking of the communication target.

[0063] The master control subsystem is used to control the hardware power supply switch and self-test of each subsystem.

[0064] like Figure 2 As shown in the system workflow diagram, the overall workflow of the above-mentioned space-based space target super-resolution imaging and ranging communication integrated system includes the following steps:

[0065] Step 1: The master control subsystem controls each subsystem to start up, supplies power to the hardware of each subsystem, and each subsystem enters the self-check state. After the self-check is completed, the system starts to work normally.

[0066] Step 2: Detect the initial orbit and position information of the target through the target survey subsystem, determine the spatial range of the detected target, control the tracking turntable to point to the target, and achieve coarse tracking of the target.

[0067] Step 3: Collect the target reflection information, use the precision tracking detector to perform high-frequency imaging of the target, and control the galvanometer to ensure that the target is continuously located in the center of the field of view to achieve stable precision tracking.

[0068] Step 4: Based on the precise tracking imaging, use the multi-dimensional super-diffraction sub-pixel imaging subsystem to perform spectral detection and polarization imaging on the target, and simultaneously obtain information such as the target shape, size, and material.

[0069] Step 5: Based on precise tracking, a ranging laser pulse signal is emitted to the target, and a laser ranging echo signal reflected by the target is received. The target distance information is calculated according to the time difference to complete the laser ranging.

[0070] Step 6: Input the acquired target location information, distance information and multi-dimensional image information into the information processing subsystem for fusion and processing, so as to realize target characteristic recognition. The processed data can also be displayed on the display screen, transmitted to the information transmission subsystem and fed back to the general control subsystem.

[0071] Step 7: Complete the capture and rough tracking of the communication target through the information transmission subsystem.

[0072] Step 8. On the basis of stable tracking, the information transmission subsystem completes the target information transmission and transmits the acquired target orbit information, image information, attribute information, etc. to the management department.

[0073] As another exemplary embodiment, Figure 3 As shown in the detailed structural diagram of the system, the space-based space target super-resolution imaging and ranging communication integrated system also includes: a card-type telescopic optical antenna.

[0074] The cassette-type telescopic optical antenna is installed on the detection and tracking turntable. The cassette-type telescopic optical antenna is the optical path part shared by the precision tracking detection subsystem, the target ranging subsystem and the multi-dimensional super-diffraction sub-pixel imaging subsystem. The cassette-type telescopic optical antenna is used to increase the optical receiving and transmitting aperture, so as to collect more target information detection energy and reduce the ranging laser divergence angle to achieve long-distance detection and ranging.

[0075] As an optional improvement scheme, in this embodiment, the target survey subsystem includes: an optical unit and a detector.

[0076] The optical unit is used to receive the sunlight reflected from the space target and focus the energy of the sunlight reflected from the space target to the target surface of the detector.

[0077] The detector is used to convert the energy received by the target surface into electrons, thereby obtaining information about the space target.

[0078] The information processing subsystem is used to determine the position coordinates of the space target based on its current posture, the direction of the detection and tracking turntable, and the position of the space target's information on the detector target surface.

[0079] The main functions of the target census subsystem are:

[0080] The space target is stared at and imaged, and a large field of view is scanned in combination with a turntable to receive sunlight reflected from the space target, thereby finding the target; and the initial coordinates of the target are determined based on the platform posture, the direction of the optical axis, and the position of the target in the image plane. The entire subsystem is required to be lightweight and compact.

[0081] like Figure 4 As shown in the workflow diagram, the specific workflow of the target census subsystem is as follows:

[0082] a) The energy of sunlight reflected by the target is gathered to the detector surface through the optical system, and the received photon energy is converted into electrons, so as to obtain target information and detect the target; large-scale detection is achieved through swing scanning.

[0083] b) Determine the initial position information 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.

[0084] c) Input the extracted target information into the tracking turntable subsystem, control the direction of the tracking turntable, ensure that the target is continuously in the field of view of the survey subsystem, and realize continuous monitoring of space targets.

[0085] d) Track the target trajectory and locate the target using laser ranging information.

[0086] As an optional improvement scheme, in this embodiment, the precision tracking detection subsystem includes: a first galvanometer, a first reflector, a first beam splitter group, a narrow-band filter, and a precision tracking detector; the first beam splitter group includes a first beam splitter and a second beam splitter.

[0087] The first galvanometer receives the reflected light beam from the space target and reflects it to the first beam splitter through the first reflector.

[0088] The first beam splitter is used to reflect a part of the reflected light beam of the space target to the multi-dimensional super-diffraction sub-pixel imaging subsystem, and transmit another part of the reflected light beam of the space target to the second beam splitter.

[0089] The second beam splitter is used to transmit a part of the light beam transmitted through the first beam splitter to the target ranging subsystem, and reflect another part of the light beam transmitted through the first beam splitter to the narrow band filter and perform high frequency imaging on the fine tracking detector.

[0090] The fine tracking detector is connected to the first galvanometer, and the fine tracking detector is used to control the first galvanometer according to the imaging result of the fine tracking detector to achieve fine tracking of the space target.

[0091] As an optional improvement scheme, in this embodiment, the target ranging subsystem includes: a high repetition rate laser transmitter, a duplex reflector and a single photon detector.

[0092] A high repetition rate laser transmitter is used to transmit high repetition rate laser to a space target; a duplex reflector is arranged on the transmission light path of the second reflector, and is used to transmit the high repetition rate laser, and reflect the reflected laser from the space target to the single photon detector; 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 obtain the distance information of the space target through the information processing subsystem.

[0093] The workflow of the target ranging subsystem is as follows:

[0094] 1) The information processing subsystem uses the spatial target position information detected by the survey subsystem to perform preliminary orbit determination and positioning of the target after solving the calculation.

[0095] 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.

[0096] 3) The precision tracking detector achieves precise tracking and alignment of the target, the laser emits laser pulses, and at the same time triggers the timing unit to start timing.

[0097] 4) The single-photon detector receives the reflected signal from the target and sends it to the timing unit to record a time difference.

[0098] 5) The computer uses prior orbital information to extract valid data from multiple sets of time differences and obtains distance information through calculation.

[0099] As an optional improvement, in this embodiment, if Figure 5 As shown in the schematic diagram of optical path propagation, the multi-dimensional super-diffraction sub-pixel imaging subsystem includes: a pupil filter, a front-end optical objective lens, a compressed sensing encoding plate, a relay lens group, a third beam splitter, a spectral detector and a polarization focal plane detector; the pupil filter, the front-end optical objective lens, the compressed sensing encoding plate, the relay lens group, the third beam splitter, the spectral detector and the polarization focal plane detector are arranged in sequence on the propagation optical path of the reflected light beam from the space target.

[0100] The pupil filter is used to modulate the wavefront to achieve super-diffraction resolution imaging. The effective aperture position and size of the pupil filter coincide with the exit pupil of the card-type telescope antenna. The position of the pupil filter is also the entrance pupil position of the multi-dimensional super-diffraction sub-pixel imaging subsystem. This is to connect the pupils of the telescope antenna and the imaging subsystem to avoid vignetting that affects the image plane illumination.

[0101] The front optical objective lens is used to image the reflected light passing through the pupil filter at the intermediate image plane of the system.

[0102] The compressed sensing encoding board is arranged at the middle image plane of the system and is used for compressed sensing encoding of scene information.

[0103] The relay mirror group is used to project the primary image plane after the compressed sensing encoding onto the surface of the spectrum detector and the polarization focal plane detector respectively through the third beam splitter.

[0104] Specifically in this embodiment, the pupil filter is a pure amplitude type, pure phase type, or complex amplitude type annular zone filter; the annular zone on the surface of the pupil filter is designed by the following steps:

[0105] According to the sub-pixel super-resolution ratio of the compressed sensing encoding plate and the pixel size of the polarization focal plane detector, the actual equivalent pixel size is calculated.

[0106] The minimum diffraction super-resolution ratio is calculated based on the point spread function radius, optical wavelength, optical system F number, super-resolution ratio and actual equivalent pixel size.

[0107] The annular zone on the surface of the pupil filter is designed according to the minimum diffraction super-resolution ratio, and the modulation function of the pupil filter is changed to make the diffraction super-resolution ratio of the pupil filter greater than or equal to the minimum diffraction super-resolution ratio.

[0108] Specifically, the minimum diffraction super-resolution ratio is first calculated. Let the pixel size of the polarization focal plane detector be α, and the sub-pixel super-resolution ratio to be achieved by the compressed sensing encoder be n. Then the actual equivalent pixel size of the system can be calculated by formula (1):

[0109] a '= a / n (1).

[0110] In this embodiment, the pixel size is 20 microns, and a large pixel detector is used to increase the received light energy, thereby increasing the detection probability. The sub-pixel super-resolution ratio achieved by compressed sensing is 4. The actual equivalent pixel size of the system is a '= a / n=5μm.

[0111] In the system design process, when the point spread function radius is less than twice the detector pixel size, the detector can effectively perform optical sampling, that is, there is a relationship as shown in formula (2):

[0112] (2).

[0113] The super-resolution ratio can be calculated by formula (3):

[0114] (3).

[0115] That is, the minimum super-resolution ratio , λ is the optical wavelength, F For optical systems F In this embodiment, λ Take the central wavelength as 0.6328 microns, the optical system F The number is 15.

[0116] According to the obtained super-resolution ratio, this super-resolution ratio is achieved by designing an annular pupil filter. Pupil filters can be of three types: pure amplitude type, pure phase type or complex amplitude type. The light field distribution at the pupil is adjusted by adjusting the amplitude of the light wave, adjusting the phase of the light wave and changing the amplitude and phase of the light wave at the same time, thereby changing the half-maximum full width of the imaging point spread function (PSF). The annular zone on the filter surface is designed by numerical optimization methods, intelligent optimization algorithms or machine learning algorithms, and the modulation function of the pupil filter is changed, so that when the parallel light beam of the working wavelength passes through this pupil filter and the entire multi-dimensional super-diffraction sub-pixel imaging subsystem, the ratio of the main lobe width of the system diffraction-limited Airy disk to the main lobe width of the point spread function formed at the focal plane is the super-resolution ratio. l , l Should be greater than or equal to l min In this embodiment, the obtained super-resolution ratio must be greater than or equal to 1.158.

[0117] In this embodiment, the pupil filter is a phase-type wavefront modulator, and the entire working area has the same transmittance to the incident light energy of the imaging wavelength. The device working area is circular and divided into multiple annular areas. The phases of two adjacent areas are different, so that the incident light passes through different areas and produces different phase shifts. The top view of the working area of ​​the device is a series of concentric rings, and the wavefront after the light passes through adjacent rings has a phase difference of π. The annular phase distribution of the pupil filter can be realized by etching a quartz plate with a height difference in each ring area. The normalized radius of each ring is finally determined by the global optimization algorithm. r 1=0.211, r 2=0.36, r 3=0.61, r4=0.73, r 5=1. Final super-resolution ratio l =1.23.

[0118] The design method of the compressed sensing encoding board is as follows:

[0119] Compressed sensing coded imaging is a new imaging mechanism that uses the sparsity of image information and coded aperture technology to solve the mathematical model through a reconstruction algorithm, thereby restoring a high-resolution target image. It can break through the detector pixel limit, achieve sub-pixel imaging, and improve resolution. n × n The code element is a "block", and each block corresponds to a pixel of the detector. Then, the collected image information is used to complete the high-resolution reconstruction of each sub-region image through the image reconstruction algorithm. Finally, the block-reconstructed images are spliced ​​into the required target scene image, thereby increasing the imaging resolution of the detector to n times the original, that is, achieving n-fold sub-pixel super-resolution imaging. That is, assuming that the resolution of the original detector is p×q, the image resolution can reach 10 ... np × nq In order to obtain effective target recovery, the specific encoding form of the compressed sensing encoding board needs to meet the RIP (Restricted Isometry Property) criterion, which mainly includes three types: random Gaussian matrix, random Fourier transform matrix, and random Bernoulli matrix.

[0120] Specifically in this embodiment, the specific encoding forms of the compressed sensing encoding plate include random Gaussian matrix, random Fourier transform matrix and random Bernoulli matrix. In this embodiment, a binary measurement matrix among the above three is selected, that is, a random Bernoulli matrix. At this time, the code type of the encoding plate is only 0 and 1, which can be realized by laser direct writing and etching a black glass substrate, that is, 1 is "fully transparent" and 0 is "opaque".

[0121] The specific sampling and reconstruction method of the compressed sensing encoding board in this embodiment is as follows:

[0122] 1) Sparse basis selection. Since natural images are compressible in certain transform domains, commonly used sparse transforms include: wavelet transform (Wavelet), discrete cosine transform (DCT), curvelet transform (Curvelet), etc. DCT transform and wavelet transform have better sparsity and flexibility. The JPEG and JPEG2000 image compression standards have also verified the good performance of these two sparse bases. They are intended to be used separately in simulation, and finally the one with better effect is selected from DCT basis and wavelet basis;

[0123] 2) Initial image acquisition and vectorization. The acquisition method is described as shown in formula (5):

[0124] (5).

[0125] in, Where each row is the measurement matrix of the vectorized DMD measurement matrix. is a sparse basis matrix, s is the sparse coefficient, which is the last one to be solved, given by s High-resolution images can be reconstructed x .

[0126] Compressed sensing reconstruction algorithm: A greedy algorithm based on the L0 norm, orthogonal matching pursuit (OMP), is used to achieve 4 times sub-pixel super-resolution reconstruction.

[0127] The spectral detector is a fiber optic spectrometer, which does not produce images. The incident light is coupled into the spectrometer through the optical fiber, and the light of different wavelengths is dispersed by the grating, and then enters the photoelectric conversion device through the slit, and finally the spectral data is obtained.

[0128] Specifically in this embodiment, the polarization focal plane detector combines polarization measurement technology and focal plane array technology, and can simultaneously obtain intensity information and polarization information of the target object, and can obtain sub-pixel super-resolution image information after reconstruction.

[0129] As mentioned above, the multi-dimensional super-diffraction sub-pixel imaging subsystem has achieved 1.23 times super-diffraction resolution and 4 times sub-pixel super-resolution imaging. It should be noted that this subsystem combines the super-diffraction resolution technology based on pupil filters and the sub-pixel super-resolution imaging technology based on compressed sensing. It improves the optical resolution of the system by breaking through the Rayleigh criterion and improves the detector pixel resolution of the system by using sub-pixel super-resolution technology. The two together determine the precision of target detection.

[0130] As an optional improvement scheme, in this embodiment, the information processing subsystem first performs polarization spectrum data fusion processing, and then uses polarization spectrum data for target identification and tracking. Select multiple spectral channels-polarization directions to generate multi-spectral-polarization images, so that for all targets of interest, their target images can be highlighted in at least one spectral-polarization sub-image. Based on the prior knowledge of each target (such as image grain data in the multi-spectral-polarization mode), from hundreds of spectral-polarization sub-images, the sub-image that can highlight the target features in the current local environment is automatically selected and used to achieve image matching of multiple targets.

[0131] In the image matching application, the decomposition feature space of the image in the sub-color domain is first established, and a strong suppression effect is applied to the features similar to the target in the search area, thereby automatically highlighting the role of the sub-color domain with unique target features in matching, and significantly increasing the weight of the unique features of weak image targets in the similarity index. This method can obtain the optimal image matching results in the sense of posterior probability. In addition, this method can obtain a more accurate target center position, which is conducive to real-time visual model update and target scale adaptive adjustment.

[0132] The multispectral-polarization image generated by multiple spectral channels-polarization directions is also a multi-channel decomposition method for real scene images. After the sub-images are partitioned by pixel intensity, similar sub-domain feature spaces can be generated. Under the assumption that the multispectral channels meet certain mutual independence conditions, the target matching method is used to strengthen the role of a few spectral-polarization sub-images with prominent target features in the local background in matching decisions, thereby realizing the recognition and tracking of multiple target features.

[0133] As an optional improvement scheme, in this embodiment, the information transmission subsystem includes a precision tracking unit and a communication unit, which can realize beacon capture, alignment, tracking and communication transmission and reception. Its workflow is as follows:

[0134] a) Multi-point guidance and pointing: Use GPS / INS to determine the position, attitude and motion trajectory of the communication target and adjust the spatial coordinates of the information transmission subsystem.

[0135] b) The information transmission subsystem enters the working state from the dormant state according to the communication instruction. The communication start time and communication duration are initially determined; the terminal generates various control parameters related to scanning and capturing; and the initialization of each part is completed. All internal units of the information transmission subsystem need to self-check, and only after the self-check is successful can the link communication be officially carried out.

[0136] c) Multi-point capture alignment: According to the position, posture and motion trajectory of multiple targets, the communication tracking turntable is adjusted to achieve capture and coarse tracking.

[0137] d) Fine tracking: The residual tracking error is further suppressed by using a galvanometer, and the fine tracking accuracy can reach 5µrad.

[0138] e) Two-way communication: Under the premise of stable tracking, two-way dynamic communication is realized.

[0139] As an optional improvement scheme, in this embodiment, the space-based space target super-resolution imaging and ranging communication integrated system also includes: an electronically controlled auxiliary subsystem; the electronically controlled auxiliary subsystem 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 entire 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.

[0140] Of course, it should be noted that Figure 3 The system architecture shown is only exemplary and can be omitted according to actual needs when implementing different functions. Figure 3 One or at least two components of the system shown.

[0141] In summary, the present application provides an integrated system for super-resolution imaging and ranging communication of space-based space targets, which can ensure high-resolution imaging while using a large pixel detector, that is, by increasing the receiving area of ​​a single pixel of the detector, thereby obtaining more light energy; in traditional cases, according to the optical system pixel resolution = pixel size / system optical focal length, a large pixel means a low target resolution, but the present application not only does not reduce the resolution of the target, but improves it. Based on a multi-dimensional super-diffraction sub-pixel imaging subsystem, diffraction super-resolution and sub-pixel super-resolution are simultaneously achieved, thereby maximizing the ability to identify target details. Such a system for achieving diffraction super-resolution and sub-pixel super-resolution has not been reported so far. Therefore, the present application can solve the problem that centimeter-level targets are dark, weak, and difficult to detect and identify. It can also simultaneously obtain multi-dimensional (polarization, spectrum, intensity) information to obtain multiple characteristics of the target, thereby improving the detection rate and recognition rate, and can realize the rapid early warning and avoidance of small space targets by our spacecraft, and develop our space security and confrontation technology.

[0142] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A space-based space target super-resolution imaging and ranging communication integrated system, It is characterized in that include: Target survey subsystem, precision tracking detection subsystem, target ranging subsystem, multi-dimensional super-diffraction sub-pixel imaging subsystem, information transmission subsystem, information processing subsystem, tracking turntable subsystem and general control subsystem; The target survey subsystem is arranged on the detection and tracking turntable, and is used to realize long-distance detection of space targets by using a high-sensitivity optical detection unit, and obtain the position coordinates of the space targets by solving the information processing subsystem; The precision tracking detection subsystem is used to perform high-frequency imaging of the space target using the precision tracking detector, and control the galvanometer according to the high-frequency imaging to ensure that the space target is continuously located at the center of the field of view, thereby 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 calculation by the information processing subsystem; The multi-dimensional super-diffraction sub-pixel imaging subsystem is used to realize spectral and polarization multi-dimensional detection imaging of space targets, and realize attribute recognition of space targets through the information processing subsystem; The information transmission subsystem is arranged on the communication tracking turntable, and is used to realize the positioning and tracking of the communication target by using laser communication and transmit the relevant information of the space target to the communication target; The information processing subsystem is used to realize the calculation of the position coordinates of the space target, the calculation of the distance measurement information of the space target and the attribute recognition of the space target by using an integrated high-speed processing chip and an information fusion algorithm; 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; It is also used to control the rotation of the communication tracking turntable according to the positioning of the communication target to achieve tracking of the communication target; The master control subsystem is used to control the hardware power supply switch and self-test work of each subsystem; The multi-dimensional super-diffraction sub-pixel imaging subsystem comprises: a pupil filter, a front-end optical objective lens, a compressed sensing encoding plate, a relay lens group, a third beam splitter, a spectrum detector and a polarization focal plane detector; the pupil filter, the front-end optical objective lens, the compressed sensing encoding plate, the relay lens group, the third beam splitter, the spectrum detector and the polarization focal plane detector are sequentially arranged on a propagation optical path of a reflected light beam from the space target; The pupil filter is used to modulate the wavefront to achieve super-diffraction resolution imaging; The front optical objective lens is used to image the reflected light passing through the pupil filter at the intermediate image plane of the system; The compressed sensing encoding board is arranged at the middle image plane of the system and is used to perform compressed sensing encoding on the scene information; The relay mirror group is used to project the primary image plane after the compressed sensing encoding onto the surfaces of the spectrum detector and the polarization focal plane detector respectively through the third beam splitter; The pupil filter is specifically a pure amplitude type, pure phase type or complex amplitude type annular zone filter; the annular zone on the surface of the pupil filter is designed by the following steps: Calculating an actual equivalent pixel size according to the sub-pixel super-resolution ratio of the compressed sensing encoding plate and the pixel size of the polarization focal plane detector; The minimum diffraction super-resolution ratio is calculated based on the point spread function radius, optical wavelength, optical system F number, super-resolution ratio and actual equivalent pixel size; Designing the annular zone on the surface of the pupil filter according to the minimum diffraction super-resolution magnification, changing the modulation function of the pupil filter, so that the diffraction super-resolution magnification of the pupil filter is greater than or equal to the minimum diffraction super-resolution magnification; The polarization focal plane detector combines polarization measurement technology and focal plane array technology, and can simultaneously obtain intensity information and polarization information of a target object, and can obtain sub-pixel super-resolution image information after reconstruction.

2. The space-based space target super-resolution imaging and ranging communication integrated system according to claim 1, It is characterized in that Also includes: Card-type telescopic optical antenna; The cassette-type telescopic optical antenna is arranged on the detection and tracking turntable. The cassette-type telescopic optical antenna is the optical path part shared by the precision tracking detection subsystem, the target ranging subsystem and the multi-dimensional super-diffraction sub-pixel imaging subsystem; the cassette-type telescopic optical antenna is used to increase the optical receiving and transmitting aperture, so as to collect more target information detection energy, and reduce the ranging laser divergence angle to achieve long-distance detection and ranging.

3. The space-based space target super-resolution imaging and ranging communication integrated system according to claim 1, It is characterized in that The target survey subsystem includes: an optical unit and a detector; The optical unit is used to receive sunlight reflected from the 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; The information processing subsystem is used to determine the position coordinates of the space target according to 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.

4. The space-based space target super-resolution imaging and ranging communication integrated system according to claim 1, It is characterized in that The precision tracking detection subsystem comprises: a first galvanometer, a first reflector, a first beam splitter group, a narrow-band filter, and a precision tracking detector; the first beam splitter group comprises a first beam splitter and a second beam splitter; The first galvanometer receives the reflected light beam from the space target, and reflects the light beam to the first beam splitter through the first reflector; The first beam splitter is used to reflect a part of the reflected light beam of the space target to the multi-dimensional super-diffraction sub-pixel imaging subsystem, and transmit another part of the reflected light beam of the space target to the second beam splitter; The second beam splitter is used to transmit a portion of the light beam transmitted through the first beam splitter to the target ranging subsystem, and reflect another portion of the light beam transmitted through the first beam splitter to the narrow-band filter and perform high-frequency imaging on the fine tracking detector; The fine tracking detector is connected to the first galvanometer, and the fine tracking detector is used to control the first galvanometer according to the imaging result of the fine tracking detector to achieve fine tracking of the space target.

5. The space-based space target super-resolution imaging and ranging communication integrated system according to claim 4, It is characterized in that The target ranging subsystem includes: a high repetition rate laser transmitter, a duplex reflector and a single photon detector; The high repetition rate laser transmitter is used to transmit high repetition rate laser to the space target; the duplex reflector is arranged on the transmission light path of the second beam splitter, and is used to transmit the high repetition rate laser and reflect the reflected laser from the space target to the single photon detector; 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 obtain the distance information of the space target through the information processing subsystem.

6. The space-based space target super-resolution imaging and ranging communication integrated system according to claim 1, It is characterized in that The specific encoding forms of the compressed sensing encoding board include random Gaussian matrix, random Fourier transform matrix and random Bernoulli matrix.

7. The space-based space target super-resolution imaging and ranging communication integrated system according to claim 1, It is characterized in that Also includes: Electronic control Auxiliary subsystems; The electric control auxiliary subsystem 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 the 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.

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