Inter-satellite laser communication system based on visual positioning assisted link establishment and link establishment method

Abstract

The invention provides an inter-satellite laser communication system based on visual positioning assisted link establishment and a link establishment method. The system comprises a laser communication machine which comprises a processor and an optical head and is used for realizing laser link establishment and laser communication; the optical detection camera, the rotary table and the sensing positioning module form a visual positioning subsystem which is used for observing and positioning a passive end target, namely a communication opposite end satellite; the measurement and control data transmission module is used for receiving data and instructions from the ground and sending satellite telemetry data; and the satellite service management module is used for realizing task management and control management of a load single machine. The inter-satellite laser communication link establishment method is suitable for inter-satellite laser communication link establishment of satellites in orbit, especially inter-satellite laser communication link establishment in under-communication and high-dynamic scenes. By using visual positioning assistance, the dependence on a ground station and external data can be reduced, the laser link establishment time is shortened, the use scene is expanded, and the stability and robustness of a satellite laser communication system are enhanced.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and more specifically, to an inter-satellite laser communication system and method based on visual positioning-assisted link establishment. Background Technology

[0002] Satellite laser communication link establishment technology enables two satellites to link in space using an extremely narrow laser beam. The core of this technology is to aim, capture, and lock the line of sight of the laser terminals within a range of hundreds to thousands of kilometers, and then maintain high-precision tracking to establish a high-speed laser communication link.

[0003] Currently, satellite laser communication suffers from challenges such as difficulty in link establishment and acquisition, and link instability. The orbital information of the passive satellite is one of the necessary input conditions for establishing a link in laser communication, primarily transmitted via ground stations, resulting in poor real-time performance and reliability. During the initial link establishment phase over long distances, when orbital maneuvers or under-communication conditions exist, the active satellite cannot obtain the real-time, accurate orbital information of the passive satellite at the current moment, making rapid acquisition difficult. Summary of the Invention

[0004] To address the aforementioned shortcomings in the prior art, this invention provides an inter-satellite laser communication system and method based on visual positioning-assisted link establishment.

[0005] According to one aspect of the present invention, an inter-satellite laser communication system based on visual positioning-assisted link establishment is provided, comprising: a functional payload and a satellite platform; the functional payload includes: a laser communication unit, an optical detection camera, and a turntable; the satellite platform includes: a sensing and positioning module, a satellite management module, and a telemetry, tracking, and command (TT&C) and data transmission module; wherein: The laser communication device is used to establish inter-satellite laser links and conduct laser communication. The optical detection camera, turntable, and sensing and positioning module constitute a visual positioning subsystem, which is used to observe and locate the passive target, namely the communication peer satellite. The telemetry and control data transmission module is used to receive ground-based data and instructions and to send satellite telemetry data; The satellite management module is used to implement task management and control management of individual payload units.

[0006] Preferably, the laser communication device includes an optical head and a processor; wherein, the optical head is equipped with a turntable for rotating in the horizontal and pitch directions to realize the spatial transmission, reception and beam pointing control of laser signals, and the optical head is also equipped with a capture and tracking control module for controlling the establishment process of the laser link; the processor is used to realize signal control and processing, link control and comprehensive load management in laser communication.

[0007] Preferably, the laser communication link is established between two satellites, each of which is equipped with a laser communication device and a visual positioning subsystem. The detection field of view of the visual positioning subsystem covers the laser communication area. In this case, any one satellite is designated as the active satellite that initiates the laser link establishment, while the other satellite is designated as the passive satellite.

[0008] According to another aspect of the present invention, a visual positioning-assisted inter-satellite laser communication link establishment method based on the system implemented in any one of the above-described embodiments of the present invention is provided, comprising: Within the telemetry and control area, the ground telemetry and control station uploads the ephemeris table and orbital parameters of the passive satellite to the active satellite. After receiving the uploaded data, the satellite telemetry and control data transmission module of the active satellite forwards it to the sensing and positioning module and the laser communication device. The active satellite tracks and positions the passive satellite in real time through the visual positioning subsystem, outputs the current orbital position of the passive satellite in real time, and sends it to the laser communication device via the satellite management module; After receiving the link establishment command, the laser communication device of the active satellite performs initial alignment based on the current orbital position of the target satellite; After initial alignment is completed, the active satellite performs an active scan, and the passive satellite sends a response signal after detecting the scan signal, achieving single-end acquisition; The active satellite responds with optical signals and adjusts its scanning range accordingly to achieve dual-end acquisition and complete the open-loop scanning process. After initial acquisition is achieved at both ends, the tracking detector detects the spot signal and establishes coarse tracking. Through continuous adjustments, the spot is kept near the center of the detector. The detector uses windowing technology to switch between frame rate and field of view. When the spot enters the field of view of the tracking detector, fine tracking is established. The two ends continuously re-establish fine tracking through coarse tracking and / or open-loop scanning; once fine tracking is stable, the link between the active end satellite and the passive end satellite is successfully established and communication begins.

[0009] Preferably, both satellites are equipped with a laser communication device and a visual positioning subsystem, wherein the visual positioning subsystem is used only when the corresponding satellite is the active satellite.

[0010] Preferably, the active satellite tracks, observes, and positions the passive satellite in real time through a visual positioning subsystem, including: The active satellite adjusts its attitude and turntable rotation angle based on the azimuth of the passive satellite, and acquires optical detection images containing the passive satellite through the visual positioning subsystem. Combining trajectory features, star map matching, and image association matching technologies, it achieves target detection and identification of the passive satellite. The visual positioning subsystem employs a space non-cooperative target visual positioning technology based on orbital dynamics and Kalman filtering. It uses the elevation and azimuth information of the target satellite acquired by the optical detection camera as observation data, combines it with the Earth's gravity field model to predict orbital dynamics, and achieves precise positioning of the target satellite through Kalman filtering. Through coordinated control of satellite attitude and turntable, it performs tracking observation and real-time positioning of the target satellite.

[0011] Preferably, when the active satellite performs real-time positioning of the passive satellite, it mainly adopts a single-satellite positioning method, that is, the active satellite performs visual positioning of the passive satellite; when conditions permit, a dual-satellite positioning method may also be adopted as needed, that is, a third satellite C is introduced, and the active satellite and the introduced C satellite simultaneously perform visual positioning of the passive satellite to improve positioning accuracy.

[0012] Preferably, the real-time output of the current orbital position of the passive satellite, and its transmission to the laser communication device via the satellite management module, includes: It updates and outputs the orbital position of the target satellite in real time; The visual positioning subsystem transmits the positioning results of the target satellite to the laser communication unit via satellite service for initial laser link establishment and alignment.

[0013] Preferably, the initial alignment process further includes: When the positioning information output by the visual positioning subsystem is valid, the active satellite prioritizes using the real-time orbital position of the passive satellite output by the visual positioning subsystem during laser link establishment; when the positioning information output by the visual positioning subsystem is invalid, the laser communication device on the active satellite extrapolates the orbit based on the orbital parameters of the passive satellite annotated on the ground to obtain the predicted value of the passive satellite's orbital position at the current moment.

[0014] Preferably, the laser communication link is established under normal conditions, or under non-measurement and control areas, under conditions of poor communication, or under conditions of high mobility.

[0015] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art: The inter-satellite laser communication system and link establishment method based on visual positioning assistance provided by this invention utilizes the optical detection camera payload commonly used on satellites for real-time target positioning, enabling rapid acquisition and link establishment of inter-satellite laser communication under conditions such as non-telemetry and control areas, insufficient communication, and high maneuverability. This helps to shorten the inter-satellite laser communication link establishment time and improve the overall stability of the laser communication link.

[0016] The inter-satellite laser communication system and link establishment method based on visual positioning assistance provided by this invention use visual positioning assistance to obtain positioning information, making full use of the advantages of the wide field of view and large coverage of the optical detection camera. Combined with target tracking technology that adopts satellite attitude and turntable coordinated control and space non-cooperative target visual positioning technology based on orbit dynamics and Kalman filtering, it can obtain real-time and accurate orbit information of target satellites, reducing the dependence on ground station data and other inter-satellite communication links (such as microwave communication).

[0017] The inter-satellite laser communication system and link establishment method based on visual positioning assistance provided by this invention can obtain real-time and accurate orbit information of the passive satellite through visual positioning assistance in high-maneuver scenarios of the target satellite, thereby improving the accuracy of orbit data, increasing the success rate of laser link establishment, and shortening the link establishment time.

[0018] The inter-satellite laser communication system and link establishment method based on visual positioning assistance provided by this invention improves the accuracy of target recognition by combining trajectory morphology and star map matching; achieves high-precision positioning of moving targets by using space non-cooperative target visual positioning technology based on orbital dynamics and Kalman filtering; and ensures the stability and effectiveness of visual positioning by adopting target tracking technology with satellite attitude and turntable coordinated control.

[0019] The inter-satellite laser communication system and link establishment method based on visual positioning assistance provided by this invention are suitable for rapid and stable link establishment in two-satellite on-orbit inter-satellite laser communication. Especially in situations where it is impossible to obtain the real-time and accurate orbital position of the target satellite through external means, such as in non-telemetry and control areas, under-communication scenarios, or high-maneuverability environments, this method has significant advantages. It reduces dependence on ground stations, reduces the frequency of ground orbital data uploading, improves the success rate of laser communication link establishment, shortens the link establishment time, and ensures communication stability, thus having high engineering application value. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the composition structure of an inter-satellite laser communication system based on visual positioning-assisted link establishment in a preferred embodiment of the present invention.

[0021] Figure 2 This is a diagram illustrating the working principle and internal logic of an inter-satellite laser communication system based on visual positioning-assisted link establishment, according to a preferred embodiment of the present invention.

[0022] Figure 3 This is a flowchart illustrating the workflow of a visual positioning-assisted inter-satellite laser communication link establishment method in a preferred embodiment of the present invention. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0024] In existing technologies, satellite laser communication typically suffers from difficulties in link establishment and acquisition, as well as link instability. The passive end of the link establishment process primarily obtains orbital information through ground station uploading or inter-satellite communication, resulting in poor real-time performance and reliability. During the initial link establishment phase over long distances, when orbital maneuvers or insufficient communication occur, the active end cannot obtain the real-time, accurate orbital information from the passive end, making rapid acquisition difficult.

[0025] To address the aforementioned issues, one embodiment of the present invention provides an inter-satellite laser communication system based on visual positioning-assisted link establishment. This system utilizes a commonly used optical detection camera payload on satellites for real-time target positioning, enabling rapid acquisition and link establishment for inter-satellite laser communication under conditions such as non-telemetry and control areas, insufficient communication, and high maneuverability. This helps to shorten the inter-satellite laser communication link establishment time and improve the overall stability of the laser communication link.

[0026] Specifically, such as Figure 1 As shown, the inter-satellite laser communication system based on visual positioning-assisted link establishment provided in this embodiment may include: a functional payload and a satellite platform; the functional payload includes: a laser communication unit, an optical detection camera, and a turntable; the satellite platform includes: a sensing and positioning module, a satellite management module, and a telemetry, tracking, and command (TT&C) data transmission module; wherein: Laser communication device, used to realize laser link establishment and laser communication; The optical detection camera, turntable, and sensing and positioning module constitute the visual positioning subsystem, which is used to observe and locate the passive target, namely the communication peer satellite. The telemetry, tracking, and command (TT&C) data transmission module is used to receive ground-based data and commands as well as to transmit satellite telemetry data. The Star Service Management module is used to implement mission management and control management of individual payloads.

[0027] In some preferred embodiments, the laser communication device includes an optical head and a processor; wherein, the optical head is equipped with a turntable for rotating in the horizontal and pitch directions to realize the spatial transmission, reception and beam pointing control of laser signals, and the optical head is also equipped with a capture and tracking control module for controlling the establishment process of the laser link; the processor is used to realize signal control and processing, link control and comprehensive load management in laser communication.

[0028] In some preferred embodiments, the laser communication link is established between two satellites, each equipped with a laser communication device and a visual positioning subsystem. The detection field of view of the visual positioning subsystem covers the laser communication area. Either satellite is designated as the active satellite initiating the laser link establishment, while the other satellite acts as the passive satellite. For ease of description, the satellite initiating the laser link establishment is referred to as the active satellite (A satellite), and the other satellite as the passive satellite (B satellite). The roles of the active and passive satellites are not fixed; both satellites can act as the active satellite. The working principle and internal logic of the inter-satellite laser communication system using visual positioning-assisted link establishment are described below. Figure 2 As shown.

[0029] Based on the inter-satellite laser communication system provided in the above embodiments of the present invention, an embodiment of the present invention also provides an inter-satellite laser communication link establishment method based on visual positioning assistance.

[0030] Specifically, such as Figure 3 As shown, the inter-satellite laser communication link establishment method based on visual positioning assistance provided in this embodiment may include: S1, within the telemetry and control area, the ground telemetry and control station uploads the ephemeris table and orbital parameters of the passive satellite to the active satellite. After receiving the uploaded data, the satellite telemetry and control data transmission module of the active satellite forwards it to the sensing and positioning module and the laser communication device. S2, the active satellite tracks and observes the passive satellite in real time through the visual positioning subsystem, outputs the current orbital position of the passive satellite in real time, and sends it to the laser communication device through the satellite management module; S3, after receiving the link establishment command, the laser communication device of the active satellite performs initial alignment based on the current orbital position of the target satellite; S4, after initial alignment is completed, the active satellite performs active scanning, and the passive satellite sends a response signal after detecting the scanning signal, achieving single-end acquisition; S5, the active end satellite responds with optical signals, and adjusts the scanning range with each other to achieve dual-end acquisition and complete the open-loop scanning process; S6. After initial acquisition is achieved at both ends, the tracking detector detects the spot signal and establishes coarse tracking. Through continuous adjustments, the spot is kept near the center of the detector. The detector uses windowing technology to switch between frame rate and field of view. When the spot enters the field of view of the tracking detector, fine tracking is established. S7 continuously re-establishes fine tracking through coarse tracking and / or open-loop scanning at both ends; once fine tracking is stable, the link between the active and passive satellites is successfully established and communication begins.

[0031] In some preferred embodiments, both satellites are equipped with a laser communication device and a visual positioning subsystem. The visual positioning subsystem is used only when the respective satellite is acting as the active satellite.

[0032] In some preferred embodiments, in S2 above, the active satellite tracks and observes the passive satellite in real time through a visual positioning subsystem, outputs the current orbital position of the passive satellite in real time, and sends it to the laser communication device via the satellite management module. This may further include: S21, the active satellite adjusts its attitude and turntable rotation angle according to the azimuth of the passive satellite, and acquires optical detection images containing the passive satellite through the visual positioning subsystem. Combining trajectory features, star map matching and image association matching technologies, it realizes target detection and identification of the passive satellite. The visual positioning subsystem employs a space non-cooperative target visual positioning technology based on orbital dynamics and Kalman filtering. It uses the elevation and azimuth information of the target satellite acquired by the optical detection camera as observation data, combines it with a high-precision Earth gravity field model for orbital dynamics prediction, and achieves accurate positioning of the target satellite through Kalman filtering (such as UKF). Through coordinated control of satellite attitude and turntable, it performs tracking observation and real-time positioning of the target satellite.

[0033] S22, through coordinated control of satellite attitude and turntable, tracks, observes and positions the target satellite, and updates and outputs the target satellite's orbital position in real time; S23, the visual positioning subsystem transmits the positioning results of the target satellite to the laser communication unit via satellite service for initial laser link establishment alignment.

[0034] In some preferred embodiments, in S21 above, when the active satellite performs real-time positioning of the passive satellite, it mainly adopts a single-satellite positioning method, that is, the active satellite performs visual positioning of the passive satellite; when conditions permit, a dual-satellite positioning method is also adopted as needed, that is, a third satellite C is introduced, and the active satellite and the introduced C satellite simultaneously perform visual positioning of the passive satellite to improve positioning accuracy.

[0035] In some preferred embodiments, the above-mentioned S3, in the initial alignment process, further includes: When the positioning information output by the visual positioning subsystem is valid, the active satellite prioritizes using the real-time, high-precision orbital position of the passive satellite output by the visual positioning subsystem during laser link establishment. When the positioning information output by the visual positioning subsystem is invalid, the laser communication device on the active satellite extrapolates the orbit based on the orbital parameters of the passive satellite annotated on the ground to obtain the predicted value of the passive satellite's orbital position at the current moment.

[0036] In some preferred embodiments, the laser communication link can be established under normal conditions, or under non-measurement and control areas, under conditions of insufficient communication, or under conditions of high mobility.

[0037] The technical solution provided by the above embodiments of the present invention will be further described in detail below with reference to a specific application example.

[0038] In this specific application example, the inter-satellite laser communication system based on visual positioning assistance includes two functional payloads: a laser communication unit and an optical detection camera and a turntable, as well as related modules in the satellite platform: a sensing and positioning module, a satellite management module, and a telemetry, tracking, and command (TT&C) data transmission module. For example... Figure 1 As shown in the diagram. The laser communication unit includes an optical head, a processor, and corresponding software to achieve laser link establishment and laser communication functions; the optical detection camera, turntable, and sensing and positioning module constitute a visual positioning subsystem to achieve observation and positioning of passive targets; the telemetry, tracking, and command (TT&C) module is used to receive data and commands from the ground and send telemetry data; the satellite management module implements process management and control management of individual units. Since this example mainly focuses on under-communication scenarios, it is assumed that other inter-satellite communication links besides laser communication do not exist or are currently unavailable.

[0039] The laser communication link is established between two satellites, each equipped with a laser communication device and a visual positioning subsystem. The satellite that actively initiates the laser link establishment is referred to as the active satellite, denoted as Satellite A; the other is called the passive satellite, denoted as Satellite B. This example uses a single-satellite positioning method, but under certain conditions, binocular positioning can also be performed to improve positioning accuracy.

[0040] The inter-satellite laser communication link establishment method using visual positioning assistance mainly consists of three stages: ground-based ephemeris and orbital parameter registration; target tracking and positioning; and laser link establishment. This scheme focuses on the initial acquisition stage of laser link establishment, using visual positioning information to assist in the alignment of the passive satellite.

[0041] like Figure 2 and Figure 3 As shown, the specific chain-building process is as follows: (1) Within the telemetry and control area, the ground telemetry and control station transmits the orbital parameters of satellite B to satellite A. After receiving the transmitted data, the satellite telemetry and control data transmission module forwards it to the sensing and positioning module and the laser communication device.

[0042] (2) Satellite A tracks and positions Satellite B in real time through the visual positioning subsystem, outputting Satellite B's current orbital position in real time, which is then transmitted to the laser communication unit via the satellite management module. When the visual positioning subsystem cannot observe the target, the satellite's attitude can be adjusted and the target tracked and observed through coordinated control of the satellite attitude and the turntable. Further, the following steps are included: 1) Target scanning and recognition. By combining techniques such as trajectory feature analysis, star map matching, and image association matching, moving targets can be detected and extracted.

[0043] 2) Target tracking and positioning. Target tracking and observation are performed through coordinated control of satellite attitude and turntable; a high-precision gravity field model is used as the system's prediction model, and monocular and binocular angle measurement and positioning models are used as the system's observation model. Kalman filtering is used to achieve accurate positioning of the target satellite.

[0044] 3) Positioning result output. The target positioning result is output to the laser communication device in real time via satellite.

[0045] (3) After receiving the link establishment command, the laser communication unit of Satellite A performs initial alignment based on the ephemeris and orbital parameters. If the positioning information output by the visual positioning subsystem is valid, the positioning information output by the visual positioning subsystem is used first; if it is invalid, the orbital extrapolation data is used.

[0046] (4) After the initial alignment is completed, satellite A performs an active scan. After satellite B detects the scan pattern, it sends a response signal and performs single-end capture.

[0047] (5) The A satellite responds to the optical signal and adjusts the scanning range to achieve dual-end capture and complete the open-loop scanning process.

[0048] (6) After initial acquisition is achieved at both ends, the tracking detector detects the spot signal and establishes coarse tracking. Through continuous adjustments, the spot is kept near the center of the detector. The detector uses windowing technology to achieve rapid switching of frame rate and field of view. When the spot enters the field of view of the fine tracking detector, fine tracking is established. However, the spot may escape the fine tracking field of view, and the terminal needs to re-establish fine tracking through coarse tracking or even open-loop scanning. After the fine tracking is stable, the link between terminals A and B is successfully established and communication begins.

[0049] As demonstrated by the above specific application examples, the inter-satellite laser communication system and link establishment method based on visual positioning assistance provided in the embodiments of the present invention are suitable for rapid and stable link establishment in two-satellite on-orbit inter-satellite laser communication, and are particularly suitable for satellite laser communication link establishment in non-telemetry and control areas, under-communication, or high-dynamic scenarios. By using visual positioning assistance, reliance on ground stations and other inter-satellite communication links can be reduced, laser link establishment time can be shortened, application scenarios can be expanded, and the stability and robustness of the satellite laser communication system can be enhanced.

[0050] Any matters not covered in the above embodiments of the present invention are well-known in the art.

[0051] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. An inter-satellite laser communication system based on visual positioning auxiliary link establishment, characterized in that, The application relates to a satellite system for laser communication, which comprises a functional load and a satellite platform. The functional load comprises a laser communication machine and an optical detection camera and a turntable, and the satellite platform comprises a perception positioning module, a satellite service management module and a measurement and control data transmission module. The laser communication machine is used for realizing inter-satellite laser link establishment and laser communication. The optical detection camera and the turntable and the perception positioning module constitute a visual positioning subsystem, which is used for realizing observation and positioning of a passive end target, i.e. a communication opposite end satellite. The measurement and control data transmission module is used for receiving ground data and instructions and sending satellite telemetry data. The satellite service management module is used for realizing task management and control management of the load single machine. The laser communication machine comprises an optical head and a processor; the optical head is provided with a turntable and is used for rotating in horizontal and pitching directions, realizing space emission, reception and beam pointing control of laser signals, and a capture tracking control module is further arranged on the optical head and is used for controlling the establishment process of a laser link; the processor is used for realizing signal control and processing, link control and load comprehensive management in laser communication.

2. The inter-satellite laser communication system based on visual positioning auxiliary link establishment according to claim 1, characterized in that, A laser communication link is established between two satellites, each of which is provided with a laser communication machine and a visual positioning subsystem, and a detection field range of the visual positioning subsystem covers a laser communication region range; wherein any one of the satellites is taken as an active end satellite which initiates laser link establishment, and the opposite end satellite is taken as a passive end satellite. 3.The visual positioning aided link establishment based inter-satellite laser communication system according to claim 1, wherein, The application further relates to a laser communication method of the satellite system.

4. A method for establishing a link of inter-satellite laser communication based on visual positioning assistance, implemented based on the system according to any one of claims 1-3, characterized in that, In a measurement and control region, a ground measurement and control station uploads an ephemeris table of the active end satellite and orbit parameters of the passive end satellite, and a satellite measurement and control data transmission module of the active end satellite receives the uploaded data and then forwards the data to the perception positioning module and the laser communication machine. The active end satellite tracks and observes the passive end satellite through the visual positioning subsystem and realizes real-time positioning, and outputs a current orbit position of the passive end satellite in real time and sends the position to the laser communication machine through the satellite service management module. The laser communication machine of the active end satellite receives a link establishment instruction and performs initial alignment according to the current orbit position of the target satellite. After the initial alignment is completed, the active end satellite performs active scanning, the passive end satellite sends a response signal after detecting the scanning signal, and single-end capture is realized. The active end satellite responds to the optical signal, adjusts the scanning range, realizes double-end capture and completes the open-loop scanning process. After the double-end preliminary capture is realized, a tracking detector detects a light spot signal, coarse tracking is established, the light spot is always maintained near the center of the detector through continuous adjustment, the detector realizes switching of frame frequency and a field of view through windowing technology, and fine tracking is established when the light spot enters the field of view range of the tracking detector. The double-end continuously re-establishes fine tracking through coarse tracking and / or open-loop scanning. When the fine tracking is stable, the link between the active end satellite and the passive end satellite is successfully established and communication is realized. Both of the two satellites are provided with a laser communication machine and a visual positioning subsystem, wherein the visual positioning subsystem is only used when the corresponding satellite is taken as an active end satellite.

5. The method of claim 4, wherein, The active end satellite tracks and observes the passive end satellite through the visual positioning subsystem and realizes real-time positioning, which comprises the following steps.

6. The method of claim 4, wherein, ​ The active end satellite adjusts the satellite attitude and the rotating angle of the turntable according to the azimuth of the passive end satellite, acquires an optical detection image containing the passive end satellite through a visual positioning subsystem, and realizes target detection and identification of the passive end satellite by combining trajectory characteristics, star map matching and image correlation matching technology; the visual positioning subsystem adopts a space non-cooperative target visual positioning technology based on orbit dynamics and Kalman filtering, takes the elevation and azimuth information of the target satellite acquired by the optical detection camera as observation data, combines an earth gravity field model to perform orbit dynamics prediction, and realizes accurate positioning of the target satellite through Kalman filtering; the target satellite is tracked and observed and real-time positioned through cooperative control of the satellite attitude and the turntable.

7. The method of claim 6, wherein, When the active end satellite performs real-time positioning on the passive end satellite, a single-satellite positioning mode is mainly adopted, that is, the active end satellite performs visual positioning on the passive end satellite; when conditions are met, a double-satellite positioning mode is also adopted according to needs, that is, a third satellite C is introduced, and the active end satellite and the introduced C perform visual positioning on the passive end satellite at the same time, so as to improve the positioning accuracy.

8. The method of claim 6, wherein, The real-time output of the current orbit position of the passive end satellite is sent to the laser communication machine through a satellite management module, and includes: Real-time updating and output of the orbit position of the target satellite; The positioning result of the target satellite is sent to the laser communication machine through the satellite management module by the visual positioning subsystem, and is used for initial alignment of laser chain establishment.

9. The method of claim 4, wherein, In the initial alignment process, it further includes: When the positioning information output by the visual positioning subsystem is valid, the active end satellite preferentially uses the real-time orbit position of the passive end satellite output by the visual positioning subsystem during laser chain establishment; when the positioning information output by the visual positioning subsystem is invalid, the laser communication machine on the active end satellite performs orbit extrapolation according to the orbit parameters of the passive end satellite annotated on the ground to obtain a prediction value of the orbit position of the passive end satellite at the current time.

10. The method of claim 4-9, wherein, The laser communication link is established under normal conditions, or is established under non-measurement and control area, under-communication or high-mobility conditions.

Images