A space laser communication terminal integrated with tracking and an intersatellite laser communication method

Abstract

The application discloses a kind of integrated space laser communication terminal and inter-satellite laser communication method, the acquisition mechanism and tracking mechanism of this laser communication terminal use same mechanism component, when carrying out acquisition in orbit and link establishment, utilize large-stroke fast mirror to carry out pointing scanning, after the laser communication terminal of opposite satellite receives the light beam of the laser communication terminal of this side, both sides laser communication terminal enters precision tracking link establishment immediately;If the position of opposite satellite exceeds the scanning range of the laser communication terminal of this side, utilize the pre-pointing and angle unloading correction of the platform of this side.The design of laser communication terminal transceiving optics, receiving communication light and transmitting communication light share an optical assembly, simple and reliable, large divergence angle is used to realize larger scanning area, reduce acquisition time and improve acquisition probability.The application uses integrated acquisition and tracking design scheme, reduces the system complexity, weight, size and power consumption of laser communication terminal.

Description

Technical Field

[0001] This invention relates to the field of space laser communication technology, specifically to an integrated space laser communication terminal and inter-satellite laser communication method, which is particularly suitable for high-speed laser communication between microsatellite platforms on the same orbital plane. Background Technology

[0002] Space laser communication technology combines the advantages of radio and fiber optic communication, using lasers as carriers for communication. It boasts strong anti-interference capabilities, high communication speeds, and no electromagnetic spectrum limitations, and has been widely applied in inter-satellite and satellite-to-ground communication in recent years. With the development of aerospace technology, satellite internet can carry increasingly rich information, including traditional remote sensing, detection, and navigation information, as well as multimedia information from end users. Space laser communication technology is a crucial means to solve the problem of high-speed inter-satellite data transmission in the future. However, the development, launch, and on-orbit maintenance of large satellites are costly. Therefore, miniaturization, lightweighting, and low cost are inevitable development trends for satellites. As an important satellite payload, laser communication terminals must also consider simplified design, reducing system complexity, size, weight, and power consumption.

[0003] Traditional laser communication terminals typically include a turntable mechanism for large-area scanning and coarse tracking to achieve wide-area scanning. This mechanism generally comprises electromagnetic motors, stepper motors, shaft systems, or other complex transmission mechanisms. The optical antenna is mounted on the turntable mechanism. This turntable mechanism significantly limits the space available for reducing the size, weight, and power consumption of the laser communication terminal. For satellite platforms, especially smaller microsatellite platforms, their high mobility and simple on-orbit attitude adjustment make it easy to achieve this. Therefore, by utilizing the attitude adjustment and pointing capabilities of microsatellite platforms, eliminating the turntable mechanism for large-area scanning and coarse tracking can greatly reduce the system complexity, size, weight, and power consumption of the laser communication terminal, saving necessary resources.

[0004] Currently, there are no publicly reported examples, either domestically or internationally, of laser communication terminals that integrate the acquisition and tracking mechanisms and eliminate the coarse pointing mechanism. Therefore, it is necessary to propose a novel integrated acquisition and tracking space laser communication terminal to address the problems of system complexity, large size, and high power consumption in existing technologies, and to meet the urgent need of microsatellite platforms for lightweight, high-performance laser communication terminals. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing space laser communication terminals, which suffer from system complexity, large size, heavy weight, and high power consumption due to the use of large-area coarse pointing mechanisms and large-aperture optical antennas. This invention provides an integrated acquisition and tracking space laser communication terminal that eliminates the large-area coarse pointing mechanism and large-aperture optical antenna found in traditional terminals. Instead, it adopts a highly integrated design, integrating acquisition and tracking functions into the same optical mechanism and employing technologies such as a common transmit / receive optical path and a long-stroke fast-reflecting mirror. This fully utilizes the attitude adjustment capabilities of the satellite platform, ultimately achieving a significant reduction in terminal system complexity, weight, size, and power consumption, while ensuring high acquisition probability, tracking accuracy, and on-orbit communication reliability.

[0006] The technical solution of the present invention is as follows:

[0007] An integrated space laser communication terminal for acquisition and tracking is characterized by comprising: a structural shell, transceiver optical components, acquisition and tracking components, and a communication transceiver module;

[0008] The transceiver optical components are suspended inside the structural housing by multiple flexible mounting feet, achieving vibration isolation and heat insulation with the structural housing;

[0009] The capture and tracking assembly includes a long-stroke fast reflector and a four-quadrant detector. The long-stroke fast reflector serves as a common actuator for scanning capture and precise tracking of the beam.

[0010] The communication transceiver module is connected to the transceiver optical component via an optical fiber.

[0011] The transceiver optical components, the acquisition and tracking components, and the communication transceiver module together constitute an integrated optomechanical system.

[0012] Furthermore, the transceiver optical assembly includes a transmitting and receiving assembly, a λ / 2 waveplate, a first folding mirror, a 22.5° wavelength beam splitter, and a second folding mirror arranged sequentially along a common optical path; a long-stroke fast reflector is disposed on the reflected optical path of the second folding mirror; a λ / 4 waveplate and a solar filter are sequentially disposed on the reflected optical path of the long-stroke fast reflector, and finally lead to the optical window at the top of the terminal; the four-quadrant detector receives the reflected beam from the 22.5° wavelength beam splitter through the QD receiving assembly, and an aperture and a narrowband filter are disposed in front of the optical path entrance of the QD receiving assembly.

[0013] The aiming, acquisition, and tracking utilize the same mechanical component, namely the integrated capture and tracking design;

[0014] The design uses the same lens tube assembly for both transmitting and receiving communication light, eliminating the inter-satellite lead angle adjustment mechanism. This greatly simplifies the design and ensures strict coaxiality between transmission and reception (given the small lead angle between the currently carried satellites, the lead angle adjustment mechanism is eliminated; for satellite platforms with larger lead angles, a lead angle adjustment mechanism can be added accordingly).

[0015] The reception of communication light and the reception of fine beacon light are achieved by wavelength splitting. Based on the actual coating design, a splitting scheme with a beam incident angle of 22.5° is adopted.

[0016] The effective light-transmitting aperture at the exit pupil is 23.6mm;

[0017] The four-quadrant detector (QD fine tracking component) has a 20mm diameter aperture and a 1nm narrowband filter in front of the lens tube to improve tracking performance;

[0018] In terms of polarization design, the λ / 4 waveplate is placed near the optical exit position, and the internal beam is adjusted by the emission λ / 2 waveplate, so that it is linearly polarized in the S or P direction, thereby avoiding the requirement for the coating to be in phase in the S and P directions, and reducing the difficulty of coating implementation.

[0019] A long-stroke fast-reflection mirror is used as both the aiming and acquisition mechanism and the fine tracking mechanism. The mechanical deflection angle is ±6mrad on both axes. At a beam angle of 22.5°, the corresponding beam deflection angle is ±12mrad in the horizontal direction and ±11.1mrad in the vertical direction.

[0020] After modulation, the transmitted communication light is combined with the transmitted fine beacon light, meaning that the transmitted communication light and the transmitted fine beacon light share the same amplifier and enter the transmitting and receiving components through the same optical fiber, thereby ensuring the directional consistency of the transmitted communication light and the transmitted fine beacon light;

[0021] The communication optical synthesis employs three methods—polarization, wavelength, and detection bandwidth—to improve isolation. The transmitted communication light wavelength is 1550.52nm, with right-hand circular polarization, while the received communication light wavelength is 1549.72nm, with left-hand circular polarization. The local oscillator and the transmitted communication light frequencies differ by more than 100GHz, ultimately achieving an isolation greater than 120dB.

[0022] The precision beacon beam employs three methods—polarization, wavelength, and frequency isolation—to improve isolation. The emitted precision beacon beam has a wavelength of 1560.20 nm and is right-hand circularly polarized, while the received precision beacon beam has a wavelength of 1540.16 nm and is left-hand circularly polarized. The emitted precision beacon beam is continuous light, while the received precision beacon beam is single-frequency modulated light. Combined with frequency isolation, the final isolation level is greater than 120 dB.

[0023] After the transceiver optical system is bonded and installed with the lens mount, substrate, etc., it is called the transceiver optical assembly. It is located inside the laser communication terminal. The transceiver optical assembly itself is an independent component. After assembly and adjustment, it is installed inside the laser communication terminal structural housing with flexible feet that have both vibration reduction and heat insulation functions to achieve heat insulation and vibration isolation between the transceiver optical assembly and the external module.

[0024] The transceiver optical assembly is approximately suspended within the housing. Under thermal conditions, the vibration damping and heat insulation pad will deform, causing a slow, slight deflection of the entire transceiver optical assembly. The transceiver optical assembly adopts a frame structure and is made of aluminum-based silicon carbide (25% SiC / 2009Al). The lens assembly is fixed at three points using a flange. The transceiver optical assembly is further encapsulated by multiple thermal control layers and independently temperature-controlled, which can eliminate the relative changes between the transmitting optical axis and the QD receiving optical axis caused by the lack of a beam-expanding optical antenna. The variation of the fine tracking point within the working range is less than 1 / 5 of the exit pupil divergence angle, fully meeting the requirements for on-orbit tracking.

[0025] Second, the present invention also provides an inter-satellite laser communication method, implemented based on the above-mentioned integrated acquisition and tracking space laser communication terminal, characterized in that the method includes:

[0026] Initial capture phase: Control the long-stroke fast-reflecting mirror to perform a wide-range scan;

[0027] Precision tracking phase: After the four-quadrant detector receives the signal from the other party's terminal, it switches to high-precision tracking mode, and the large-stroke fast-reflecting mirror performs precise tracking.

[0028] Platform-assisted pointing phase: If the other party terminal exceeds the scanning range of the large-stroke fast reflector, the satellite platform is controlled to adjust its attitude to achieve pre-pointing and angle unloading correction.

[0029] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0030] To address the issue of current laser communication terminals typically employing large-area coarse pointing mechanisms and large-aperture optical antennas, resulting in generally high weight, size, and power consumption, this design eliminates these components and adopts an integrated acquisition and tracking design. This significantly reduces the system complexity, weight, size, and power consumption of the laser communication terminal, lowers development costs, and improves reliability. Simultaneously, it alleviates the design burden on the satellite platform, reducing its complexity and manufacturing costs. Furthermore, the substantial reduction in the overall weight and size of the satellite allows for the use of lighter and more economical launch vehicles, further reducing satellite development costs. Attached Figure Description

[0031] Figure 1 This is a diagram of the transceiver optical system of the integrated space laser communication terminal of the present invention.

[0032] Figure 2 This is a schematic diagram of the transceiver component design of the integrated space laser communication terminal of the present invention.

[0033] Figure 3 This is a structural model diagram of the transceiver components of the integrated space laser communication terminal of the present invention.

[0034] Figure 4 This is a schematic diagram of the installation of the transceiver optical components of the integrated space laser communication terminal of the present invention inside the laser communication terminal.

[0035] Figure 5 This is a schematic diagram of the system working principle of the integrated space laser communication terminal for tracking and capturing according to the present invention.

[0036] In the diagram: 1-Transmitter / receiver assembly, 2-Shared transmit / receive fiber, 3-Acquisition and tracking detector, 4-QD receiver assembly, 5-Acquisition and tracking actuator, 6-22.5° wavelength beam splitter, 7-First folding mirror, 8-Second folding mirror, 9-Aperture stop, 10-Narrowband filter, 11-λ / 2 waveplate, 12-λ / 4 waveplate, 13-Solar filter. Detailed Implementation

[0037] The embodiments of the present invention will be further described and illustrated below with reference to the accompanying drawings. A detailed implementation and operation process is provided. 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.

[0038] like Figure 1-2 As shown, the transmit / receive assembly 1, which shares the same aperture, adopts a three-element aspherical lens structure with an optical focal length of 86.4 mm, integrating the transmit and receive optical paths. The aspherical design corrects wave aberrations and ensures beam quality.

[0039] The transmitted and received light are transmitted through a shared optical fiber 2. In this embodiment, a single-fiber bidirectional (BIDI) optical fiber is used to achieve coaxial bidirectional transmission and reduce system complexity.

[0040] The first conversion mirror 7 and the second conversion mirror 8 construct a Z-shaped folded optical path, enabling the transmitter-receiver assembly 1, the acquisition-tracking detector 3 (QD four-quadrant detector), and the acquisition-tracking actuator 5 (fast-reflecting mirror) to form a compact optical path structure. The optical axis enters the subsequent processing module after two reflections, effectively compressing the size of the optical system. Among them, the acquisition-tracking detector 3 adopts a quantum dot (QD) four-quadrant detector, which has high quantum efficiency and wide spectral response characteristics.

[0041] A receiving beam-contraction lens group (QD receiver assembly 4) is set in front of the acquisition and tracking detector 3. It adopts a three-lens structure to improve beam quality, with a tracking field of view of 2mrad and a focal length of 150mm.

[0042] The capture and tracking actuator 5 adopts a large-stroke fast mirror (FSM), with an optical axis tracking range greater than ±0.5 degrees and a tracking disturbance suppression capability greater than 120Hz, which can meet the capture and tracking requirements in the on-orbit environment of the satellite platform.

[0043] 22.5° wavelength beam splitter 6 is used to isolate the communication light and the fine beacon light by wavelength;

[0044] The first and second convoluted mirrors 7 and 8 construct a folded optical path, realizing the reflection of the optical axis and forming multiple optical paths such as transmission and reception, QD detection, and acquisition and tracking actuators. This makes the optical system compact and simple, facilitating optical assembly and adjustment. The aperture 9 and narrowband filter 10 are placed in front of the QD receiving component 4 to form a stray light suppression module, further improving the tracking isolation.

[0045] The λ / 2 waveplate 11 is used to adjust the linear polarization direction of the transmitted and received communication light;

[0046] The λ / 4 waveplate 12 switches between linearly polarized and circularly polarized light for transmitting and receiving communication light.

[0047] A solar filter 13 is placed at the optical window position to eliminate the influence of stray light such as sunlight and improve tracking and communication isolation.

[0048] Both the λ / 2 waveplate 11 and the solar filter 13 are placed at a 5° angle to avoid the influence of backlight.

[0049] The workflow is as follows:

[0050] Transmission path: The transmission communication light and the transmission fine beacon light are emitted through the transmission and reception component 1, and then pass through the λ / 2 waveplate 11, the first folding mirror 7, the 22.5° wavelength beam splitter 6, the second folding mirror 8, the acquisition and tracking actuator 5, the λ / 4 waveplate 12, and the solar filter 13 in sequence, and finally emitted from the optical window (exit pupil).

[0051] Receiving path: The receiving communication light enters through the optical window, passes through the solar filter 13, λ / 4 waveplate 12, capture and track actuator 5, second folding mirror 8, 22.5° wavelength beam splitter 6, first folding mirror 7, λ / 2 waveplate 11, and transmit and receive assembly 1 before being coupled into the shared transmit and receive fiber 2; the receiving fine beacon light enters through the optical window, passes through the aperture 9 and narrowband filter 10 for noise filtering, and is focused by QD receiver assembly 4 onto the photosensitive surface of capture and track detector 3, where position detection is performed based on the optical power energy distribution.

[0052] In summary, the transceiver optical system of the integrated capture and tracking space laser communication terminal consists of a transmit and receive component, a capture and tracking detector (four-quadrant detector), a capture and tracking actuator (fast-reflecting mirror), several turning mirrors, beam splitters, and waveplates, etc., which is simple and reliable.

[0053] See Figure 2 and Figure 3 The optical substrate is made of aluminum-based silicon carbide material and has a frame structure. All lens groups are mounted by means of the structural end face and the side of the vertical structural wall of the optical substrate. That is, the mounting surface is perpendicular to the coplanar plane of the optical axis travel of the optical system. The entire transceiver optical assembly is a frame optical structure system.

[0054] See Figure 4 The transceiver optical components used for space optical path transmission and reception in the laser communication terminal are located inside the optical transceiver module. The transceiver optical components are independent components and are installed inside the laser communication terminal through three flexible mounting feet. They are vibration- and heat-insulated from the platform. The transceiver components are covered with multiple layers and have independent temperature control. Combined with the frame design of the optical substrate, the relative relationship between the receiving beacon optical axis and the transmitting communication optical axis changes very little within the working range, ensuring long-term stable tracking and communication performance.

[0055] An opening with an effective diameter of 25mm is made at the top of the laser communication terminal structure, which serves as both the output of the optical system's emitted light and the input of the received light.

[0056] See Figure 5 The laser communication terminal system mainly consists of a communication transceiver section, a capture and tracking section, and a power supply and main control section.

[0057] The capture and tracking section refers to the transceiver optical system;

[0058] Since there is no beam-expanding optical antenna, the receiving gain is relatively small. The system adopts a coherent receiving communication scheme to ensure receiving communication sensitivity and anti-interference capability.

[0059] The communication transceiver section functions as the light source and signal processing part of the laser communication terminal, mainly including the modulation of transmitted communication light, generation and amplification of transmitted communication light and transmitted fine beacon light, generation and amplification of local oscillator light, amplification and demodulation of received communication light, phase-locked communication, and processing, storage and forwarding of demodulated signals, etc.

[0060] The main functions of the power supply control section are to generate secondary power, drive the light source, four-quadrant detector and fast reflector, and control the logic and temperature of the laser communication terminal system.

[0061] Example:

[0062] This embodiment provides an integrated space laser communication terminal for low-Earth orbit microsatellite platforms. The terminal specifically includes a structural housing, transceiver optical components, acquisition and tracking components, and a communication transceiver module.

[0063] 1. Optomechanical layout and installation

[0064] The transceiver optical assembly is the core component of the terminal. Its optical substrate and support frame are made of aluminum-based silicon carbide (25%SiC / 2009Al) material with high thermal stability and high specific stiffness, and are precision-machined into an integral frame structure. All optical lenses, including the transceiver assembly 1, the first convoluted mirror 7, the second convoluted mirror 8, the 22.5° wavelength beam splitter 6, the λ / 2 waveplate 11, etc., are mounted on the vertical structural wall side of the optical substrate through flange interfaces in a three-point fixing manner, ensuring that all mounting surfaces are perpendicular to the optical axis, thereby mechanically guaranteeing the long-term stability of the optical path and the repeatability of assembly and adjustment.

[0065] The transceiver optical components, as a separate module, are mounted almost "floating" inside the terminal's structural housing via three flexible mounting feet that also provide vibration damping and heat insulation (see...). Figure 4 This installation method effectively isolates vibrations from the satellite platform and stresses generated by thermal deformation of the structural shell. Simultaneously, the entire transceiver optical assembly is entirely encased in multiple layers of thermal insulation material and equipped with an independent thermal control loop for active temperature control, ensuring it operates in a small and stable temperature field, further guaranteeing the thermal stability of the optomechanical system.

[0066] 2. Optical Path and Workflow: Transmitting Optical Path: The transmitting communication light and the transmitting beacon light are amplified by the same amplifier in the communication transceiver module and then output through the same shared transceiver fiber 2, entering the transmitting and receiving assembly 1. After being collimated by the transmitting and receiving assembly 1, the beam passes sequentially through a λ / 2 waveplate 11 (used to adjust the linear polarization direction), a first conversion mirror 7, a 22.5° wavelength beam splitter 6 (which has high transmission for the 1550nm and 1560nm bands), and a second conversion mirror 8, reaching the acquisition and tracking actuator 5 (i.e., a long-stroke fast-reflecting mirror). After being reflected by the fast-reflecting mirror, the beam then passes sequentially through a λ / 4 waveplate 12 (which converts the linearly polarized light into right-hand circularly polarized light) and a solar filter 13, finally exiting from the optical window at the top of the terminal and pointing towards the target satellite.

[0067] The receiving communication optical path: Left-handed circularly polarized light with a wavelength of 1549.72nm from the other satellite enters through the optical window and passes sequentially through the solar filter 13, the λ / 4 waveplate 12 (which converts it into linearly polarized light), the acquisition and tracking actuator 5, the second conversion mirror 8, the 22.5° wavelength beam splitter 6 (which has high transmittance for 1549.72nm communication light), the first conversion mirror 7, and the λ / 2 waveplate 11. Finally, it is converged by the transmitting and receiving component 1, coupled and retrieved through the shared optical fiber 2, and transmitted to the communication transceiver module for coherent demodulation.

[0068] The receiving beacon optical path: Left-handed circularly polarized light with a wavelength of 1540.16nm from the other satellite enters through the optical window. The initial optical path is the same as the receiving communication optical path. When it reaches the 22.5° wavelength beam splitter 6, the light beam is reflected and redirected to the beacon receiving branch. The reflected light first passes through a 20mm diameter aperture 9, effectively suppressing background stray light; then it passes through a narrowband filter 10 with a center wavelength of 1540.16nm and a bandwidth of 1nm to further filter out noise; afterwards, the beam is beam-shrunk and its quality is improved by the QD receiving component 4 (a three-lens beam-shrinking system), and finally accurately imaged onto the photosensitive surface of the acquisition and tracking detector 3 (a four-quadrant detector) to calculate the spot offset and achieve high-precision tracking.

[0069] In this embodiment, the long-stroke fast-reflection mirror (capture and tracking actuator 5) has a mechanical deflection angle of ±6 mrad across both axes. Since it is positioned in the optical path with a beam incident angle of 22.5°, according to the principles of geometric optics, the actual beam deflection range is ±12 mrad (±0.68°) in the horizontal direction and ±11.1 mrad (±0.63°) in the vertical direction. This mechanism simultaneously performs the dual functions of wide-range scanning capture and high-bandwidth (>120Hz) precise tracking.

[0070] The polarization state of each optical path is controlled by combining λ / 2 waveplate 11 and λ / 4 waveplate 12. The emitted light is right-handed circularly polarized, and the received light is left-handed circularly polarized. Combined with a wavelength / frequency difference of approximately 100 GHz (0.8 nm for communication light and 20.04 nm for beacon light) and narrowband filtering technology, an extremely high optical isolation of greater than 120 dB is achieved at the receiving end, effectively suppressing backscattering interference of its own emitted light.

[0071] When the terminal is operating, it first controls the fast reflector to perform a scanning pattern search within its maximum deflection range (acquisition phase). Once the four-quadrant detector receives the beacon light signal from the other party, the terminal immediately switches to fine tracking mode, controlling the fast reflector to operate in closed loop and maintain link stability (tracking phase). If the target exceeds the field of view of the fast reflector, the terminal reports the angle deviation information to the satellite platform, which then performs coarse pointing adjustments through attitude maneuvers (platform-assisted pointing phase) to bring the target back into the working range of the fast reflector. This collaborative working mode of "terminal fine tracking + platform coarse pointing" replaces the traditional independent coarse pointing mechanism.

[0072] The terminal provided in this embodiment, through the aforementioned integrated design, successfully eliminates the turntable-type coarse pointing mechanism and large-aperture beam-expanding optical antenna found in traditional terminals. The overall weight, size, and power consumption of the terminal are significantly reduced compared to traditional designs, making it highly suitable for mounting on microsatellite platforms weighing hundreds of kilograms or even smaller. Simultaneously, due to the reduction in moving parts and the simplification of the optical path structure, the inherent reliability of the system is greatly improved. Unique vibration isolation, heat insulation, and temperature control designs ensure that the terminal maintains long-term optical pointing stability even in harsh space environments, fully meeting the requirements of low-Earth orbit inter-satellite high-speed laser communication for acquisition probability, tracking accuracy, and communication performance.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A space laser communication terminal integrating capture and tracking, characterized in that, include: Structural housing, transceiver optical components, acquisition and tracking components, and communication transceiver module; The transceiver optical components are suspended inside the structural housing by multiple flexible mounting feet, achieving vibration isolation and heat insulation with the structural housing; The capture and tracking assembly includes a long-stroke fast reflector and a four-quadrant detector. The long-stroke fast reflector serves as a common actuator for scanning capture and precise tracking of the beam. The communication transceiver module is connected to the transceiver optical component via an optical fiber. The transceiver optical components, the acquisition and tracking components, and the communication transceiver module together constitute an integrated optomechanical system; The transceiver optical assembly includes a transmit-receive assembly, a λ / 2 waveplate, a first folding mirror, a 22.5° wavelength beam splitter, and a second folding mirror arranged in sequence along a common optical path. A long-stroke fast reflector is disposed on the reflected optical path of the second folding mirror. A λ / 4 waveplate and a solar filter are arranged in sequence on the reflected optical path of the long-stroke fast reflector, and the light ultimately leads to an optical window at the top of the terminal. The four-quadrant detector receives the reflected beam from the 22.5° wavelength beam splitter through a QD receiving assembly, and an aperture and a narrowband filter are disposed before the optical path entrance of the QD receiving assembly.

2. The integrated tracking and detection space laser communication terminal according to claim 1, characterized in that, The mechanical deflection angle of the long-stroke fast reflector is ±6 mrad on both axes. When configured in an optical path with a beam incident angle of 22.5°, it achieves a beam deflection range of ±12 mrad in the horizontal direction and ±11.1 mrad in the vertical direction.

3. The integrated tracking and detection space laser communication terminal according to claim 1, characterized in that, The transmitting and receiving components adopt a three-lens structure with an optical focal length of 86.4 mm; the QD receiving components adopt a three-lens beam-contraction structure with a focal length of 150 mm and a tracking field of view of 2 mrad.

4. The integrated capture and tracking space laser communication terminal according to claim 1, characterized in that, The communication transceiver module is connected to the transmitting and receiving component through a shared optical fiber, enabling the output of transmitting communication light and transmitting fine beacon light, as well as the input of receiving communication light.

5. The integrated capture and tracking space laser communication terminal according to claim 4, characterized in that, The transmitted communication light and the transmitted fine beacon light are amplified by the same amplifier and then output through the same shared transceiver optical fiber.

6. The integrated tracking and detection space laser communication terminal according to claim 1, characterized in that, The 22.5° wavelength beam splitter is used to separate the received communication light from the fine beacon light: the communication light is transmitted to the transmitting and receiving assembly, and the fine beacon light is reflected to the four-quadrant detector.

7. The integrated tracking and detection space laser communication terminal according to claim 1, characterized in that, The λ / 2 waveplate is used to adjust the polarization direction of the internal linearly polarized light; the λ / 4 waveplate is positioned near the optical exit and is used to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light.

8. The integrated tracking and detection space laser communication terminal according to claim 1, characterized in that, The substrate and support frame of the transceiver optical component are made of aluminum-based silicon carbide material; each optical lens is mounted on the vertical structural wall side of the substrate through a flange interface in a three-point fixing manner, and the mounting surface is perpendicular to the optical axis of the optical system.

9. The integrated capture and tracking space laser communication terminal according to claim 1, characterized in that, The number of flexible mounting feet is three, which are connected between the transceiver optical component and the structural housing. The transceiver optical component is entirely covered with multiple layers of heat insulation material and is subject to independent active temperature control.

10. An inter-satellite laser communication method, implemented based on the integrated acquisition and tracking space laser communication terminal according to any one of claims 1-9, characterized in that, The method includes: Initial capture phase: Control the long-stroke fast-reflecting mirror to perform a wide-range scan; Precision tracking phase: After the four-quadrant detector receives the signal from the other party's terminal, it switches to high-precision tracking mode, and the large-stroke fast-reflecting mirror performs precise tracking. Platform-assisted pointing phase: If the other party terminal exceeds the scanning range of the large-stroke fast reflector, the satellite platform is controlled to adjust its attitude to achieve pre-pointing and angle unloading correction.

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