Space target laser ranging, imaging and communication integrated device and method

Abstract

The application discloses a space target laser ranging, imaging, communication integrated device and method, and relates to the field of space target optical detection. In the device, the emitted light is emitted to the target through a first transmitting and receiving optical system; the target echo light is received by the first transmitting and receiving optical system, then transmitted through a first beam splitter and incident to a second beam splitter, the beacon CCD of the transmission light path of the second beam splitter is used to acquire beacon information, and the ranging detector of the reflection light path of the second beam splitter is used to acquire ranging information; the beam splitter group respectively distributes the transmitting and receiving light of the second transmitting and receiving optical system to a static passive polarization module, a two-dimensional space hyperspectral acquisition module, a laser communication transmitting unit and a laser communication receiving unit, and completes target polarization imaging, two-dimensional space hyperspectral acquisition and laser communication under the alignment control provided by an APT processing system. The application can simultaneously realize laser ranging, laser communication and target detection.

Description

Technical Field

[0001] This application relates to the field of optical detection of space targets, and in particular to an integrated device and method for laser ranging, imaging and communication of space targets. Background Technology

[0002] With the development of aerospace technology, the number of satellites launched globally each year is gradually increasing, resulting in more and more space debris. This space debris is unusable and may collide with existing satellites, seriously threatening space security and potentially causing huge losses.

[0003] To ensure space security, some countries have conducted research including dual-satellite angle measurement and positioning, space-ground joint space target detection systems, and SpaceX's Starlink project. The research undertaken by various countries mainly focuses on the detection and location of space targets to ensure space security and address potential conflicts with other countries in space. Space targets include man-made spacecraft, space debris, and asteroids. Currently, there are three main methods for observing space targets: space-based detection, ground-based detection, and combined space-ground detection. While ground-based detection technologies such as radar and photoelectric detectors are relatively mature and inexpensive, space-based detection has advantages over ground-based detection, such as being unaffected by weather and having higher flexibility, making it the mainstream detection method in most scenarios. However, these detection methods often only achieve a single purpose; currently, there is no detection system that integrates multiple purposes. Summary of the Invention

[0004] The purpose of this application is to provide an integrated device and method for laser ranging, imaging and communication of space targets, which can simultaneously realize laser ranging, laser communication and target detection.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides an integrated space target laser ranging, imaging, and communication device, comprising: a target acquisition, alignment, and tracking subsystem and an information imaging and communication transmission subsystem; The target acquisition, alignment, and tracking subsystem includes a first transceiver optical system, a camera group, a first beam splitter, a second beam splitter, a beacon CCD, an APT processing system, a laser ranging and communication transmitting unit, and a ranging detector. The laser ranging and communication transmitting unit is set on the reflective optical path of the first beam splitter. The transmitted light is transmitted to the target through the first transceiver optical system. The target echo light is received by the first transceiver optical system, passes through the first beam splitter, and is incident on the second beam splitter. The beacon CCD in the transmission optical path of the second beam splitter is used to acquire beacon information, and the ranging detector in the reflective optical path of the second beam splitter is used to acquire ranging information. The APT processing system is connected to the laser ranging and communication transmitting unit, beacon CCD, camera group and ranging detector respectively, and is used to generate acquisition, alignment and tracking control quantities based on transmission information, beacon information and ranging information; The information imaging and communication transmission subsystem includes a second transceiver optical system, a beam splitter group, a static passive polarization module, a two-dimensional spatial hyperspectral acquisition module, a laser communication transmitting unit, and a laser communication receiving unit. The beam splitter group is set on the transmission optical path of the second transceiver optical system and is used to distribute the transmitted light from the second transceiver optical system to the static passive polarization module, the two-dimensional spatial hyperspectral acquisition module, the laser communication transmitting unit, and the laser communication receiving unit, respectively. Under the alignment control provided by the APT processing system, the system completes target polarization imaging, two-dimensional spatial hyperspectral acquisition, and laser communication.

[0006] In one embodiment, the target acquisition alignment and tracking subsystem further includes: a first collimator; The first collimator is disposed between the laser ranging and communication transmitting unit and the first beam splitter; the camera group receives the light transmitted by the first collimator.

[0007] In one embodiment, the target acquisition alignment and tracking subsystem further includes: a second collimator; The second collimator is disposed between the ranging detector and the second beam splitter.

[0008] In one embodiment, the target acquisition alignment and tracking subsystem further includes: a third collimator; The third collimator is positioned between the beacon CCD and the second beam splitter.

[0009] In one embodiment, the beam splitter group includes: a third beam splitter, a fourth beam splitter, and a fifth beam splitter; The light transmitted by the second transceiver optical system passes through the third beam splitter; the third, fourth, and fifth beam splitters are coaxially arranged; the static passive polarization module is arranged on the reflected light path of the third beam splitter; the two-dimensional spatial hyperspectral acquisition module is arranged on the reflected light path of the fourth beam splitter; the laser communication transmitting unit is arranged on the reflected light path of the fifth beam splitter; and the laser communication receiving unit is arranged on the transmitted light path of the fifth beam splitter. The second transceiver optical system includes: a sixth beam splitter and a folding optical system; The imaging beam passes through the sixth beam splitter to obtain transmitted light; the transmitted light is transmitted to the folding optical system to obtain outgoing light; the outgoing light is transmitted to the third beam splitter.

[0010] In one embodiment, the sixth beam splitter is a beam splitter that is fully reflective at 1530nm-1570nm and fully transparent at 400nm-1000nm.

[0011] In one embodiment, the information imaging and communication transmission subsystem further includes: a galvanometer; The galvanometer is positioned between the second transceiver optical system and the third beam splitter.

[0012] In one embodiment, the third beam splitter is a beam splitter that is fully reflective in the 400nm-700nm range and fully transparent in the 700nm-1570nm range.

[0013] In one embodiment, the fourth beam splitter is a beam splitter that is fully transparent in the 1530nm-1570nm range and fully reflective in the 700nm-1000nm range.

[0014] Secondly, this application provides an integrated method for laser ranging, imaging, and communication of space targets, which is applied to the aforementioned integrated device for laser ranging, imaging, and communication of space targets. The integrated method includes: The system acquires laser light waves emitted by the laser ranging and communication transmitting unit, laser echoes received by the beacon CCD, laser spot images acquired by the camera group, and target optical images acquired by the two-dimensional spatial hyperspectral acquisition module. The wavefront difference is determined based on the laser wave and the laser echo; the wavefront difference characterizes the ranging target information. Based on the laser spot image and the target optical image, an image analysis using a Gaussian blur algorithm is performed to obtain a two-dimensional matrix of image information. Image data is obtained by sampling the laser spot image and the target optical image; Based on the wavefront difference and the image data, image association is performed to obtain a grayscale association matrix; The target image is obtained by fusing the gray-level correlation matrix, the image information two-dimensional matrix, the wavefront difference, and the image data.

[0015] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides an integrated device and method for laser ranging, imaging, and communication of space targets. It comprises a dual-observation system consisting of a target acquisition, alignment, and tracking subsystem and an information imaging and communication transmission subsystem. The target acquisition, alignment, and tracking subsystem enables target search, acquisition, alignment, coarse tracking, fine tracking, and laser ranging, providing stable target pointing for subsequent links. The information imaging and communication transmission subsystem enables target polarization imaging, two-dimensional spatial hyperspectral acquisition, and laser communication transmission and reception. By integrating the target acquisition, alignment, and tracking subsystem and the information imaging and communication transmission subsystem into a single device, the overall device achieves integrated laser ranging, imaging, and communication, simultaneously realizing laser ranging, laser communication, and target detection. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of a space target laser ranging, imaging and communication integrated device; Figure 2 A block diagram illustrating the principle of an integrated laser ranging, imaging, and communication device for space targets.

[0018] Reference numerals: Target acquisition, alignment and tracking subsystem 1, second transceiver optical system 2, imaging and communication processing system 3, static passive polarization module 36, two-dimensional spatial hyperspectral acquisition module 37, laser communication transmitting unit 38, laser communication receiving unit 39, APT processing system 10, first beam splitter 11, second beam splitter 12, third collimator 13, first collimator 14, second collimator 15, laser ranging and communication transmitting unit and camera group 16, ranging detector 17, beacon CCD 18, sixth beam splitter 21, folding optical system 22, galvanometer 30, third beam splitter 31, fourth beam splitter 32, fifth beam splitter 33, first condenser 34, second condenser 35. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In one exemplary embodiment, such as Figure 1 As shown, a space target laser ranging, imaging and communication integrated device is provided, including: a target acquisition, alignment and tracking subsystem 1 and an information imaging and communication transmission subsystem.

[0022] The target acquisition, alignment and tracking subsystem 1 includes a first transceiver optical system, a camera group, a first beam splitter 11, a second beam splitter 12, a beacon CCD 18, an APT processing system 10, a laser ranging and communication transmitting unit and a camera group 16, and a ranging detector 17.

[0023] The laser ranging communication transmitting unit is located on the reflected light path of the first beam splitter 11. The transmitted light is emitted to the target via the first transceiver optical system. The target echo light is received by the first transceiver optical system, passes through the first beam splitter 11, and is incident on the second beam splitter 12. The beacon CCD 18 in the transmission light path of the second beam splitter 12 is used to acquire beacon information, and the ranging detector 17 in the reflected light path of the second beam splitter 12 is used to acquire ranging information. The APT processing system 10 is connected to the laser ranging communication transmitting unit, the beacon CCD 18, the camera group, and the ranging detector 17, respectively, and is used to generate acquisition, alignment, and tracking control quantities based on the transmission information, beacon information, and ranging information.

[0024] Specifically, the first transceiver optical system, the first beam splitter 11, the second beam splitter 12, and the beacon CCD 18 are on the same transmission optical path; the APT processing system 10 is connected to the laser ranging communication transmitting unit and the beacon CCD 18 respectively; the APT processing system 10 is used to generate capture, alignment, and tracking control quantities based on the transmitted light, echo signal, and beacon information; ranging is completed by the corresponding channel of the ranging detector 17, and communication is completed by the laser communication transmitting unit 38 and the laser communication receiving unit 39; the laser ranging communication transmitting unit and the camera group 16 are both located on the reflected optical path of the first beam splitter 11; the ranging detector 17 is located on the reflected optical path of the second beam splitter 12; the camera group and the ranging detector 17 are both connected to the APT processing system 10.

[0025] The information imaging and communication transmission subsystem includes a second transceiver optical system 2 and an imaging and communication processing system 3. The second transceiver optical system 2 includes a sixth beam splitter 21 and a catadioptric optical system 22. The imaging and communication processing system 3 includes a beam splitter group, a static passive polarization module 36, a two-dimensional spatial hyperspectral acquisition module 37, a laser communication transmitting unit 38, and a laser communication receiving unit 39. The beam splitter group includes a third beam splitter 31, a fourth beam splitter 32, and a fifth beam splitter 33.

[0026] The beam splitter group is set on the transmission optical path of the second transceiver optical system 2, and is used to distribute the light emitted by the second transceiver optical system 2 to the static passive polarization module 36, the two-dimensional spatial hyperspectral acquisition module 37, the laser communication transmitting unit 38 and the laser communication receiving unit 39 respectively, and complete the target polarization imaging, two-dimensional spatial hyperspectral acquisition and laser communication under the alignment control provided by the APT processing system 10.

[0027] The light transmitted by the second transceiver optical system 2 passes through the third beam splitter 31; the third beam splitter 31, the fourth beam splitter 32, and the fifth beam splitter 33 are coaxially arranged; the static passive polarization module 36 is arranged on the reflected light path of the third beam splitter 31; the two-dimensional spatial hyperspectral acquisition module 37 is arranged on the reflected light path of the fourth beam splitter 32; the laser communication transmitting unit 38 is arranged on the reflected light path of the fifth beam splitter 33; and the laser communication receiving unit 39 is arranged on the transmitted light path of the fifth beam splitter 33.

[0028] The APT processing system 10 is electrically connected to the laser ranging and communication transmitting unit, beacon CCD 18, camera group, and ranging detector 17 in the target acquisition, alignment, and tracking subsystem 1. It is used to comprehensively process the transmitted signals, echo signals, and spot images in the target acquisition, alignment, and tracking subsystem 1, outputting target acquisition, pointing correction, coarse tracking, and fine tracking control quantities, and providing stable target pointing information for the information imaging and communication transmission subsystem. The ranging results are calculated by the corresponding channel of the ranging detector 17, and image analysis and fusion are completed by the imaging and communication processing system 3. The APT processing system 10 mainly undertakes the closed-loop functions of acquisition, alignment, tracking, and control.

[0029] In an exemplary embodiment, the target acquisition alignment and tracking subsystem 1 further includes: a first collimator 14; the first collimator 14 is disposed between the laser ranging and communication transmitting unit and the first beam splitter 11; the camera group receives the light transmitted by the first collimator 14.

[0030] The target acquisition, alignment and tracking subsystem 1 further includes: a second collimator 15; the second collimator 15 is disposed between the ranging detector 17 and the second beam splitter 12.

[0031] The target acquisition, alignment and tracking subsystem 1 further includes: a third collimator 13; the third collimator 13 is disposed between the beacon CCD 18 and the second beam splitter 12.

[0032] In an exemplary embodiment, the beam splitter group includes: a third beam splitter 31, a fourth beam splitter 32, and a fifth beam splitter 33; the light transmitted by the second transceiver optical system 2 passes through the third beam splitter 31; the third beam splitter 31, the fourth beam splitter 32, and the fifth beam splitter 33 are coaxially arranged; a static passive polarization module 36 is disposed on the reflected light path of the third beam splitter 31; a two-dimensional spatial hyperspectral acquisition module 37 is disposed on the reflected light path of the fourth beam splitter 32; a laser communication transmitting unit 38 is disposed on the reflected light path of the fifth beam splitter 33; a laser communication receiving unit 39 is disposed on the transmitted light path of the fifth beam splitter 33; the second transceiver optical system 2 includes: a sixth beam splitter 21 and a folding optical system 22; the imaging beam passes through the sixth beam splitter 21 to obtain transmitted light; the transmitted light is transmitted to the folding optical system 22 to obtain emitted light; the emitted light is transmitted to the third beam splitter 31. In practical applications, the folding optical system 22 is a Cassegrain telescope system.

[0033] The sixth beam splitter 21 is a beam splitter that is fully reflective in the 1530nm-1570nm range and fully transparent in the 400nm-1000nm range.

[0034] In an exemplary embodiment, the information imaging and communication transmission subsystem further includes a galvanometer 30; the galvanometer 30 is disposed between the second transceiver optical system 2 and the third beam splitter 31. A collimating lens is also disposed between the galvanometer 30 and the second transceiver optical system 2, a first condenser lens 34 is disposed between the laser communication transmitting unit 38 and the fifth beam splitter 33, and a second condenser lens 35 is disposed between the laser communication receiving unit 39 and the fifth beam splitter 33.

[0035] In practical applications, the third beam splitter 31 is a beam splitter that is fully reflective from 400nm to 700nm and fully transparent from 700nm to 1570nm. The fourth beam splitter 32 is a beam splitter that is fully transparent from 1530nm to 1570nm and fully reflective from 700nm to 1000nm.

[0036] The target acquisition, alignment, and tracking subsystem 1 mainly includes a first transceiver optical system, a first beam splitter 11, a second beam splitter 12, a first collimator 14, a second collimator 15, a third collimator 13, a laser ranging and communication transmitting unit and camera group 16, a ranging detector 17, a beacon CCD 18, and an APT processing system 10. The information imaging and communication transmission subsystem mainly includes a second transceiver optical system 2, an imaging and communication processing system 3, a static passive polarization module 36, a two-dimensional spatial hyperspectral acquisition module 37, a laser communication transmitting unit 38, and a laser communication receiving unit 39. The second transceiver optical system 2 includes a sixth beam splitter 21 and a folding optical system 22; the imaging and communication processing system 3 includes a galvanometer 30, a third beam splitter 31, a fourth beam splitter 32, and a fifth beam splitter 33.

[0037] The laser imaging, ranging, and communication integrated system proposed in this application adopts a modular design concept, consisting of a target acquisition, alignment, and tracking subsystem 1 and an information imaging and communication transmission subsystem. The information imaging and communication transmission subsystem comprises a second transceiver optical system 2 and an imaging and communication processing system 3. Specifically, the laser ranging and communication beacon share a single optical system; the information imaging and communication transmission share a single optical system; and the laser ranging light, beacon light, and communication signal light preferably share an integrated multi-wavelength light source module.

[0038] This device employs a collaborative working mode consisting of a "target acquisition, alignment, and tracking subsystem" and an "information imaging and communication transmission subsystem." During operation, the target acquisition, alignment, and tracking subsystem first completes target search, guidance pointing, acquisition alignment, coarse tracking, and laser ranging, and provides stable target pointing information to the information imaging and communication transmission subsystem. Subsequently, under stable pointing conditions, the information imaging and communication transmission subsystem completes target polarization imaging, two-dimensional spatial hyperspectral acquisition, and laser communication transmission and reception, thereby achieving integrated spatial target ranging, imaging, and communication.

[0039] Main functions include: 1) The laser ranging and communication transmitting unit emits a 1064nm active laser to scan the space target and receives the reflected light from the target for ranging; the beacon CCD receives the reflected light from the target or the beacon light from other optical transceivers to complete the laser communication coarse tracking.

[0040] 2) Imaging and communication processing system 3 performs polarization imaging under coarse tracking conditions. The polarization imaging band is 400~700nm; the aperture, focal length, and field of view are determined according to the usage environment; the laser communication transmitting unit emits signal light and simultaneously receives signal light from other optical transceivers to complete laser communication fine tracking and transmission.

[0041] 3) The laser ranging and communication transmitting unit adopts fiber phased array beam splitting-coupling technology to integrate laser ranging with beacons and signal light sources, achieving multi-wavelength, high-power, and high-stability light sources, and making the system lightweight and miniaturized.

[0042] 4) The target acquisition, alignment and tracking subsystem 1 can realize guidance pointing, acquisition alignment, coarse tracking, fine tracking and laser ranging, and provide stable target pointing information for the information imaging and communication transmission subsystem.

[0043] like Figure 2As shown, the navigation system first identifies the target and sends it to the turntable. If it is a friendly unit emitting a beacon / range-finding laser, both units will also emit beacon / range-finding lasers. The two sides will achieve acquisition and tracking through the APT (Alignment, Acquisition, Tracking) system, and simultaneously perform full polarization imaging. The received range-finding light will be processed to achieve laser ranging, and a communication laser will be emitted for communication. If it is a non-cooperative target, a range-finding laser will be emitted, and the target will be acquired and tracked through its own APT processing system. The reflected light will be ranged, and the target will be fully polarized imaged. The obtained information will then be transmitted back to the friendly unit through the laser communication system.

[0044] To address the shortcomings of existing space target detection devices, this application offers superior detection performance by employing a combination of Cassegrain laser ranging and laser communication for target detection.

[0045] The hardware structure of this application includes an information imaging and communication transmission subsystem and a target acquisition, alignment, and tracking subsystem. The Cassegrain telescope system, serving as a shared transceiver antenna for both the imaging beam and the communication signal laser, is only integrated into the information imaging and communication transmission subsystem. The laser ranging system and laser communication beacon link are integrated into the target acquisition, alignment, and tracking subsystem, perpendicular to the main optical axis of the first transceiver optical system. Optical path reversal is achieved through a first beam splitter 11 and a second beam splitter 12. Furthermore, the laser ranging and communication transmitting unit and the ranging detector are separated through two stages of beam splitters. The laser communication link of the information imaging and communication transmission subsystem is located at the rear end of the imaging detection unit, with its optical axis perpendicular to the main imaging optical axis. Optical path reversal is achieved through a fifth beam splitter 33. The laser communication transmitting unit and the laser communication receiving unit are separated through the fifth beam splitter 33. Ultimately, the main optical axes of the two subsystems are parallel, allowing for synchronous alignment with the target during target detection. The static passive polarization module and the two-dimensional spatial hyperspectral acquisition module, as imaging detection units, are located at the rear end of the outgoing optical path of the Cassegrain telescope system. They are used to receive the target light captured by the Cassegrain telescope system and achieve target optical imaging. Through the coordinated operation of the two systems, the imaging clarity and the optical imaging modulation transfer function (MTF) are ultimately improved.

[0046] This application combines laser ranging, imaging, and communication capabilities, enabling the acquisition of higher-quality target images through laser ranging and communication, and achieving stable, high-definition target detection. In today's world of abundant space debris, this application can effectively detect various types of space debris, not only assisting satellites in avoiding collisions with space debris but also accurately detecting other satellites, effectively preventing satellite capture and ensuring the safety of satellite assets. Integrating optical imaging, laser ranging, and laser communication into a single system significantly saves valuable satellite and aircraft payloads, allowing it to be deployed on various platforms such as satellites, aircraft, and ships, and widely applied in various detection fields to complete diverse tasks. This application utilizes multiple information acquisition methods to obtain multi-dimensional target information, resulting in more comprehensive information acquisition and enabling the fusion and complementarity of multi-dimensional information, leading to higher performance in optical imaging. The improved imaging quality achieves excellent results in target detection missions.

[0047] In another exemplary embodiment, a space target laser ranging, imaging, and communication integrated method is provided. This method is applied to the aforementioned space target laser ranging, imaging, and communication integrated device. The space target laser ranging, imaging, and communication integrated method includes: The system acquires laser light waves emitted by the laser ranging and communication transmitting unit, laser echoes received by the beacon CCD, laser spot images acquired by the camera group, and target optical images acquired by the two-dimensional spatial hyperspectral acquisition module.

[0048] The wavefront difference is determined based on the laser light wave and the laser echo; the wavefront difference characterizes the ranging target information.

[0049] Based on the laser spot image and the target optical image, an image analysis algorithm is used to obtain a two-dimensional matrix of image information.

[0050] Image data is obtained by sampling the laser spot image and the target optical image.

[0051] Based on the wavefront differences and the image data, image association is performed to obtain a grayscale association matrix.

[0052] The target image is obtained by fusing the gray-level correlation matrix, the image information two-dimensional matrix, the wavefront difference, and the image data.

[0053] In practical applications, the integrated method of laser ranging, imaging and communication for space targets includes the following steps.

[0054] Step 1: Device Setup. Follow... Figure 1After the device is assembled, the optical axes of the target acquisition, alignment, and tracking subsystem and the information imaging and communication transmission subsystem are calibrated to ensure that the optical paths within each subsystem meet the coaxial transmission requirements. Subsequently, common-view calibration is performed on both subsystems to ensure that their main optical axes remain parallel and synchronously point towards the target area, thus preventing alignment errors. This can be achieved by aligning the laser ranging and communication transmitting unit with a 5m collimator and emitting a 1064nm laser. An infrared camera is mounted on the side of the collimator to receive the laser spot, and the laser source is simultaneously activated at that location. The light beam is then received by both the visible light camera and the infrared camera after passing through the collimator. First, ensure the laser spot is centered on the screen, then adjust the positions of the spots received by the visible light camera and the infrared camera in the image to the exact center of the image. The visible light camera and the infrared camera form a camera group to obtain the laser spot image of the ranging laser.

[0055] Step 2: Laser ranging. The laser ranging communication transmitting unit emits a laser beam, which passes through a beam splitter and exits through the first transceiver optical system, ready to illuminate the target and receive the laser echo. At this time, the APT processing system calculates the wavefront difference between the emitted and received laser beams in real time and records it as a difference matrix. This matrix carries the information of the ranging target.

[0056] Step 3: Laser Communication. The laser communication transmitting unit in the information imaging and communication transmission subsystem emits a communication laser. After being coupled into the common optical axis by the fifth beam splitter, the communication laser is emitted to the target along the corresponding optical path of the second transceiver optical system and receives the return optical signal. It is ready to illuminate the target and receive the laser echo. At this time, the wavefront difference between the laser wave at the time of emission and the laser wave at the time of reception is calculated in real time by the APT processing system and recorded as a difference matrix. This matrix represents the wavefront difference, spot offset and pointing error information in the laser communication link.

[0057] The two steps described above use the same processing method.

[0058] For a spatial target, the image intensity in the target optical image acquired by the two-dimensional spatial hyperspectral acquisition module is the convolution of the system point spread function and the observed target distribution function. Let o(x,y) be the distribution function of the observed target; i(x,y) be the intensity distribution of the focal plane image, corresponding to the point spread function PSF(x,y); and i(x,y) be the intensity distribution of the phase difference image after introducing known aberrations, also corresponding to the point spread function PSF(x,y).

[0059] For a focal plane image, the following conditions are met in the spatial domain: .

[0060] Correspondingly, in the frequency domain, the following is satisfied: .

[0061] in O(u,v) and OTF(u,v) are the Fourier transforms of i(x,y), o(x,y) and PSF(x,y), respectively. The optical transform function OTF(u,v) is equal to the autocorrelation of the pupil function P(x,y).

[0062] .

[0063] The pupil function can be expressed as: .

[0064] Where A(x,y) is the aperture function of the telescope imaging system. Ф(x,y) is the phase of the target to be measured, which can be expressed as the Zemnike polynomial expansion shown below. Where Z(x,y) is the i-th Zemnike polynomial. Let K be the coefficient of the i-th Zernike polynomial. Here, K is the number of terms in the Zernike polynomial expansion.

[0065] .

[0066] Similarly, for phase difference images: .

[0067] .

[0068] .

[0069] .

[0070] Where Ф(x,y) is the introduced known aberration, also called the phase difference function. In practical PD technology applications, the phase difference function is usually chosen to be out-of-focus. This is because out-of-focus images are easiest to obtain when acquiring phase difference images, and the introduced phase difference Ф(x,y) can be accurately calculated based on the out-of-focus distance d.

[0071] Wavefront differences are used in optical imaging systems to suppress atmospheric effects and make optical images clearer.

[0072] Step 4: Optical Imaging. The target is imaged by the Cassegrain telescope system. The target light is split by the second transceiver optical system and the imaging and communication processing system, and the corresponding image information is acquired by the static passive polarization module and the two-dimensional spatial hyperspectral acquisition module, respectively. The imaging and communication processing system extracts pixel information and estimates the blur kernel in the acquired target image, recording it as a pixel matrix. This matrix contains complete target image information.

[0073] Step 5: Image Analysis. A single RGB pixel value matrix is ​​insufficient to obtain comprehensive image information about the target; therefore, it needs to be combined with a blur kernel matrix to obtain complete target information. Convolving these two matrices yields the complete target information.

[0074] An RGB image can be viewed as a three-dimensional data structure consisting of three color channels: .

[0075] R(x,y), G(x,y), and B(x,y) represent the red, green, and blue components of pixel (x,y), respectively. The data for each channel can be viewed as a two-dimensional matrix.

[0076] The entire image can be expanded into a matrix form: .

[0077] R HW This represents the red component value at pixel coordinates (H, W) in the image. The value typically ranges from 0 to 255 (for 8-bit images) or from 0 to 1 (after normalization). A higher value indicates a stronger red component in that pixel. G HW This represents the green component value at pixel coordinates (H, W) in the image. Its meaning is similar to the red component, used to describe the green intensity of the pixel. B HW This represents the blue component value at pixel coordinates (H, W) in the image, used to describe the blue intensity of the pixel.

[0078] Two-dimensional Gaussian blur is used to simulate the image loss during transmission: .

[0079] Where: σ is the standard deviation, which controls the fuzziness intensity. u,v are the positional offsets relative to the kernel center. The size of the fuzzy kernel is n×n, i.e., u,v∈{-k,-k+1,…,0,…,k-1,k}, where k=n-1 / 2.

[0080] The process of applying Gaussian blur to image I(x,y) can be represented as: .

[0081] It is a complete RGB color image pixel vector after Gaussian blurring, composed of the blurred red, green and blue channel components. The blurred red channel pixel value is the result at pixel (x,y) after convolving the original red channel R(x,y) with a Gaussian blur kernel. The blurred green channel pixel value is the result at pixel (x,y) after convolving the original green channel G(x,y) with a Gaussian blur kernel. The blurred blue channel pixel value is the result at pixel (x,y) after convolving the original blue channel B(x,y) with a Gaussian blur kernel.

[0082] Blur result for each channel By combining with Gaussian blur kernel weights Convolution calculation yields: .

[0083] C(xu,yv) is the pixel value located at (xu,yv) in channel C. It is the fuzzy kernel weight. k=n-1 / 2 is the radius of the kernel.

[0084] The fully blurred RGB image can be written as: .

[0085] in, This represents the pixel value at coordinates (xu, yv) in the red channel of the original image. This represents the pixel value at coordinates (xu, yv) in the green channel of the original image. This represents the pixel value at coordinates (xu, yv) in the blue channel of the original image.

[0086] To maintain the overall brightness of the image, the Gaussian blur kernel weights K(u,v) must satisfy the normalization condition: .

[0087] If it is not normalized, it can be normalized using the following formula: .

[0088] The normalized Gaussian blur kernel weights ensure that the overall brightness of the image remains unchanged after convolution, satisfying the following conditions. K(i,j) is the weight value of the unnormalized Gaussian blur kernel at coordinate (i,j), which is used to calculate the total weight of the kernel in the denominator to achieve normalization. The pixel value at coordinates (xu, yv) is the original color image vector containing three channel components (R, G, B). It is the original pixel vector participating in convolution in a unified form.

[0089] After integrating the above formulas, the Gaussian blur process of the RGB image I(x,y) can be uniformly expressed as: .

[0090] It unfolds into three channels: .

[0091] .

[0092] .

[0093] Transform it into a matrix as follows: .

[0094] Step 6: Image Sampling. Since the Cassegrain telescope system is aimed at different target positions at different locations, the position of the central occlusion is also different. Using this principle, the unobstructed areas in the two images are sampled and fused to obtain a high-quality image, thereby solving part of the aperture occlusion problem.

[0095] Define the observation system pointing vector: Target surface normal vector: Describes the surface orientation, for a point on the target surface: , serving as the base point on the plane.

[0096] The plane equation of the target surface can be expressed as: or ,in .

[0097] Let the starting point of the observation vector be... The direction of the vector pointed to by the observation system is v. The parameterized expression of the vector is: ,in, The parameterized position vector of the observation vector represents the spatial coordinates of the observation vector under parameter t.

[0098] Expanded to: .

[0099] Substitute the vector parameterized expression into the plane equation: .

[0100] Simplify: .

[0101] but .

[0102] .

[0103] Substitute into the parameterized expression, intersection point for: .

[0104] Expanded to: .

[0105] Therefore, the coordinates of the intersection point can be expressed as: .

[0106] Let the base point of the target surface be... .

[0107] With the target normal vector For the vertical direction, choose two orthogonal directions. and Construct a local coordinate system.

[0108] The expression for the intersecting plane in the local coordinate system of the target surface is: .

[0109] These are local coordinates in a plane. satisfy and . This is the position vector of the target surface in the local coordinate system.

[0110] Now we need to remove the central obstruction, which requires... . The radius threshold of the effective area of ​​the target surface.

[0111] Now we sample the image to obtain image data. : .

[0112] Step 7: Image Association. Since the wavefront information carried by the laser is completely isolated from the target image data obtained by optical imaging, it is necessary to associate the laser wavefront feature points with the optical image.

[0113] Calculate the numerical change of each pixel value in the neighborhood of the image obtained by optical imaging at this time, and the numerical change of the wavefront at each selected position after subtraction, and perform the subtraction operation.

[0114] Zero-order slope difference .

[0115] First-order slope difference .

[0116] Second-order slope difference .

[0117] Among them, the zero-order slope difference characterizes the overall absolute difference between the laser wavefront feature sequence and the optical image feature sequence within the sliding window. The larger the value, the greater the difference between the two sequences and the lower the correlation. For the first l At each location, the wavefront characteristic values ​​of the laser wavefront sensor are preprocessed and normalized. For the l-th registration position, the image feature value of the optical imaging sensor after preprocessing and normalization is denoted as . l It is the position index of the discrete sequence, which is a one-to-one correspondence number between the laser wavefront sampling point and the optical image registration pixel point. k This is the index of the target center position currently being calculated, i.e., the right endpoint of the sliding window, corresponding to the core pixel / wavefront sampling point number for which the correlation is to be calculated.

[0118] Then the type B grey relational degree of the target coordinates obtained by these two sensors is: .

[0119] Their grey relational matrix for: .

[0120] This represents the B-type gray correlation of each pixel in the image. For the k-th position, the laser wavefront sensor's preprocessed feature sequence is given. This represents the preprocessed feature sequence of the optical imaging sensor at the k-th position. The zero-order slope difference represents the absolute difference in the original values ​​of two feature sequences within the sliding window. The larger the value, the greater the difference in the basic numerical values ​​of the sequences and the lower the correlation. The first-order slope difference represents the absolute difference in the first-order difference (slope of change) between two feature sequences within the sliding window. It measures the degree of matching of the sequence change trends. The larger the value, the greater the difference in the change trends. The second-order slope difference characterizes the absolute difference of the second-order difference (curvature of change) between two feature sequences within the sliding window. It measures the matching degree of sequence change acceleration / concavity. The larger the value, the greater the difference in change morphology. Type B grey relational degree is a core indicator for quantifying the degree of correlation and matching between the feature sequence of the laser wavefront sensor and the feature sequence of the optical imaging sensor at the k-th position.

[0121] Step 8: Image High-Resolution. A high-quality image of the target can be obtained by fusing the previously obtained laser wavefront matrix (i.e., a two-dimensional matrix) with the image data.

[0122] Image fusion example.

[0123] Image transformation: The two original input images to be fused are obtained through homography transformation. and Align to a reference view: . Represents an image The i-th pixel in , with images Corresponding pixel It satisfies the homography transformation mapping relationship; It is a homography matrix that describes the spatial transformation between two images, used to align two images to the same reference view.

[0124] It is a homography matrix that describes the transformation relationship between image 1 and image 2.

[0125] , These are the corresponding pixels.

[0126] The image obtained after transformation , indicates the image in the reference view.

[0127] Parallax correction: .

[0128] It is the camera's focal length. These are the coordinates of the optical center, corresponding to the projection of the point onto another image. is the pixel coordinate vector on the camera's normalized plane.

[0129] .

[0130] After depth correction, the corresponding points are ensured to be geometrically consistent in the two images.

[0131] Light correction: Different shooting angles can lead to variations in lighting conditions. Lighting can be adjusted using normalization. .

[0132] and These are images The mean and standard deviation. To Pixel intensity values ​​after illumination normalization. Let be the grayscale / color intensity value of the i-th original input image at pixel (x,y).

[0133] Furthermore, the illumination and reflection components are separated as follows: .

[0134] For the reflection component, Illumination component.

[0135] During fusion, the consistency of the reflection components should be maintained first.

[0136] Multiscale decomposition: The two aligned images are then decomposed into multiple scales: .

[0137] The low-frequency component of the k-th layer. High-frequency components of the k-th layer. To Pixel intensity values ​​after illumination normalization.

[0138] The high-frequency and low-frequency information is obtained using Gaussian filter convolution: .

[0139] .

[0140] For the low-frequency components of the image, by and The convolution process yields images representing large-scale structures, brightness, and smooth areas. The original input image to be decomposed (the image has been aligned and preprocessed). is a Gaussian filter of the k-th layer, used for convolution with the image to extract smooth low-frequency information. The high-frequency components of the image are obtained by subtracting the low-frequency components from the original image I. This yields detailed information about the image, including its edges, textures, and details.

[0141] For low-frequency components Using a weighted average: .

[0142] Among them, weight It can be calculated using gradients or energy: .

[0143] Let be the gradient vector of the low-frequency component of the k-th layer in the i-th image at pixel (x,y), which represents the intensity of structural change at that location. Let be the gradient vector of the low-frequency component of the k-th layer in the first image at pixel (x,y). Let be the gradient vector of the low-frequency component of the k-th layer in the second image at pixel (x,y). The fusion weight of the low-frequency component of the k-th layer in the i-th image at pixel (x,y) is obtained by normalizing the gradient magnitude and is used to weight the low-frequency components of the two images, prioritizing the retention of regions with clearer structures.

[0144] For high frequency components Select using the maximum value: .

[0145] This represents the high-frequency component of the k-th layer of the first image, which contains detailed information such as edges and textures at the k-th scale of the image. This is the high-frequency component of the k-th layer of the second image, which contains detailed information such as edges and textures at the k-th scale of the image.

[0146] The fused low-frequency and high-frequency components are reconstructed to obtain the fused image. : .

[0147] The final fusion process is as follows: .

[0148] For the final fused image, It is a function operator for the entire image fusion process, integrating all operations from image alignment, multi-scale decomposition, weight calculation to component reconstruction. These are the reflection and illumination components of the first image (used for illumination correction). The reflection and illumination components of the second image (used for illumination correction).

[0149] Image retouching examples: The phase information φ(x,y) obtained by interferometry describes the spatial phase distribution of the laser wavefront, is related to the optical path difference (OPD), and reflects the structure, details, or wavefront distortion in the image.

[0150] The brightness and color distribution of an RGB image can be represented by three channels: R(x,y), G(x,y), and B(x,y), but it usually lacks accurate phase or high-frequency detail information.

[0151] By fusing the detailed characteristics of phase information φ(x,y) into an RGB image, edge sharpness, texture contrast, or optical distortion can be improved.

[0152] Perform a Fourier transform on each channel of the RGB image to decompose it into amplitude and phase: .

[0153] This is the two-dimensional Fourier transform of the red channel R(x,y), i.e., its frequency domain representation. To preserve the amplitude spectrum of the original red channel (maintaining the overall brightness and contrast of the image unchanged). This is the original phase spectrum of the red channel, describing the spatial location and structural information (corresponding to details such as edges and textures) of each frequency component in the image. This formula is the polar coordinate form of the Fourier transform, decomposing the frequency domain signal into amplitude and phase components.

[0154] Similarly, the phase information φ(x,y) obtained by interferometry for G and B is used to replace the phase spectrum of the RGB image: .

[0155] This is the frequency domain signal of the red channel after phase replacement. To preserve the amplitude spectrum of the original red channel (maintaining the overall brightness and contrast of the image unchanged). To replace the original phase spectrum with high-precision laser wavefront phase information obtained by interferometry It introduces more refined structural, edge, and texture details.

[0156] Perform an inverse Fourier transform on the modified frequency domain representation to reconstruct an enhanced RGB image. .

[0157] Ultimately, we can obtain: .

[0158] in, The red channel pixel values ​​are reconstructed after phase fusion and inverse Fourier transform, preserving the amplitude information of the original image while injecting high-precision phase details obtained by interferometry, resulting in clearer edges and textures. The green channel pixel value is reconstructed after phase fusion and inverse Fourier transform. Similarly to R′(x,y), high-precision phase detail fusion is achieved. The blue channel pixel values ​​are reconstructed after phase fusion and inverse Fourier transform, and are consistent with the first two channels, thus achieving phase enhancement.

[0159] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0160] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A space target laser ranging, imaging, and communication integrated device, characterized in that, This includes a target acquisition, alignment, and tracking subsystem and an information imaging and communication transmission subsystem; The target acquisition, alignment, and tracking subsystem includes a first transceiver optical system, a camera group, a first beam splitter, a second beam splitter, a beacon CCD, an APT processing system, a laser ranging and communication transmitting unit, and a ranging detector. The laser ranging and communication transmitting unit is set on the reflective optical path of the first beam splitter. The transmitted light is transmitted to the target through the first transceiver optical system. The target echo light is received by the first transceiver optical system, passes through the first beam splitter, and is incident on the second beam splitter. The beacon CCD in the transmission optical path of the second beam splitter is used to acquire beacon information, and the ranging detector in the reflective optical path of the second beam splitter is used to acquire ranging information. The APT processing system is connected to the laser ranging and communication transmitting unit, beacon CCD, camera group and ranging detector respectively, and is used to generate acquisition, alignment and tracking control quantities based on transmission information, beacon information and ranging information; The information imaging and communication transmission subsystem includes a second transceiver optical system, a beam splitter group, a static passive polarization module, a two-dimensional spatial hyperspectral acquisition module, a laser communication transmitting unit, and a laser communication receiving unit. The beam splitter group is set on the transmission optical path of the second transceiver optical system and is used to distribute the transmitted light from the second transceiver optical system to the static passive polarization module, the two-dimensional spatial hyperspectral acquisition module, the laser communication transmitting unit, and the laser communication receiving unit, respectively. Under the alignment control provided by the APT processing system, the system completes target polarization imaging, two-dimensional spatial hyperspectral acquisition, and laser communication.

2. The integrated space target laser ranging, imaging, and communication device according to claim 1, characterized in that, The target acquisition, alignment, and tracking subsystem further includes: a first collimator; The first collimator is disposed between the laser ranging and communication transmitting unit and the first beam splitter; the camera group receives the light transmitted by the first collimator.

3. The integrated space target laser ranging, imaging, and communication device according to claim 1, characterized in that, The target acquisition, alignment, and tracking subsystem further includes: a second collimator; The second collimator is disposed between the ranging detector and the second beam splitter.

4. The integrated space target laser ranging, imaging, and communication device according to claim 1, characterized in that, The target acquisition, alignment, and tracking subsystem also includes: a third collimator; The third collimator is positioned between the beacon CCD and the second beam splitter.

5. The integrated space target laser ranging, imaging, and communication device according to claim 1, characterized in that, The beam splitter group includes: a third beam splitter, a fourth beam splitter, and a fifth beam splitter; The light transmitted by the second transceiver optical system passes through the third beam splitter; the third, fourth, and fifth beam splitters are coaxially arranged; the static passive polarization module is arranged on the reflected light path of the third beam splitter; the two-dimensional spatial hyperspectral acquisition module is arranged on the reflected light path of the fourth beam splitter; the laser communication transmitting unit is arranged on the reflected light path of the fifth beam splitter; and the laser communication receiving unit is arranged on the transmitted light path of the fifth beam splitter. The second transceiver optical system also includes: a sixth beam splitter and a folding optical system; The imaging beam passes through the sixth beam splitter to obtain transmitted light; the transmitted light is transmitted to the folding optical system to obtain outgoing light; the outgoing light is transmitted to the third beam splitter.

6. The integrated space target laser ranging, imaging, and communication device according to claim 5, characterized in that, The sixth beam splitter is a beam splitter that is fully reflective in the 1530nm-1570nm range and fully transparent in the 400nm-1000nm range.

7. The integrated space target laser ranging, imaging, and communication device according to claim 5, characterized in that, The information imaging and communication transmission subsystem also includes: a galvanometer; The galvanometer is positioned between the second transceiver optical system and the third beam splitter.

8. The integrated space target laser ranging, imaging, and communication device according to claim 5, characterized in that, The third beam splitter is a beam splitter that is fully reflective in the 400nm-700nm range and fully transparent in the 700nm-1570nm range.

9. The integrated space target laser ranging, imaging, and communication device according to claim 5, characterized in that, The fourth beam splitter is a beam splitter that is fully transparent in the 1530nm-1570nm range and fully reflective in the 700nm-1000nm range.

10. A method for integrating laser ranging, imaging, and communication for space targets, characterized in that, The integrated method for space target laser ranging, imaging, and communication is applied to the integrated space target laser ranging, imaging, and communication device according to any one of claims 1-9, wherein the integrated method for space target laser ranging, imaging, and communication includes: The system acquires laser light waves emitted by the laser ranging and communication transmitting unit, laser echoes received by the beacon CCD, laser spot images acquired by the camera group, and target optical images acquired by the two-dimensional spatial hyperspectral acquisition module. The wavefront difference is determined based on the laser wave and the laser echo; the wavefront difference characterizes the ranging target information. Based on the laser spot image and the target optical image, an image analysis using a Gaussian blur algorithm is performed to obtain a two-dimensional matrix of image information. Image data is obtained by sampling the laser spot image and the target optical image; Based on the wavefront difference and the image data, image association is performed to obtain a grayscale association matrix; The target image is obtained by fusing the gray-level correlation matrix, the image information two-dimensional matrix, the wavefront difference, and the image data.

Images