Laser communication terminal capable of continuously adjusting beam divergence angle and beam divergence angle adjusting method

Abstract

The invention relates to a laser communication terminal capable of continuously adjusting a beam divergence angle and a beam divergence angle adjusting method, and relates to the technical field of laser communication. The device comprises an emission light path which comprises a signal light emission device, a divergence angle adjustable device, a plane reflective mirror, a DM dichroic mirror and a piezoelectric fast reflecting mirror; the receiving light path comprises a piezoelectric fast reflecting mirror and a DM dichroic mirror which are shared by the receiving light path and the emitting light path; the method comprises the following steps: constructing a non-leakage scanning model, and establishing a mathematical model between a camera capture sensitivity circle radius and a screw pitch and non-leakage scanning time; establishing a relationship among the laser beam divergence angle, the camera capture sensitivity circle radius and the laser propagation distance; and based on the target screw pitch and the target leak-free scanning time, the optimal laser beam divergence angle is solved according to the laser propagation distance. A divergence angle adjustable device is arranged in the laser communication terminal, and a mathematical model is established, so that a self-adaptive optimal beam divergence angle calculation and adjustment strategy is realized, the performance and efficiency of a system are improved, and the complexity and fault risk of the system are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of laser communications, and in particular to a laser communication terminal capable of continuously adjusting a beam divergence angle and a beam divergence angle adjustment method. Background Art

[0002] The optical antennas of current mainstream satellite-borne laser communication terminals (typically based on reflective or transmissive telescope structures such as Cassegrain and Gregorian telescopes) are designed with a fixed laser beam divergence angle. This means that the beam's coverage and spot size are fixed at a specific distance.

[0003] Beam aiming and tracking are primarily achieved through the following methods: 1. Coarse aiming mechanism: typically based on a two-dimensional turntable, providing a wide field of view for initial capture and wide-range angle adjustment; 2. Fine aiming mechanism: typically based on a fast steering mirror (FSM) or piezoelectric ceramic actuator, providing high-precision, high-bandwidth, small-angle adjustment to compensate for platform vibration and dynamic tracking errors.

[0004] Although the coarse and fine aiming mechanisms can maintain the establishment and stability of the link to a certain extent, factors such as the continuous changes in the distance between satellites or between satellites and the ground caused by satellite orbital motion, the inevitable vibration (micro-vibration) of the satellite platform itself and the limitation of attitude control accuracy, and the turbulence effect when the laser passes through the atmosphere causing the beam to drift / expand / flicker, result in the design of fixed beam divergence or two-level adjustable beam divergence having significant and difficult-to-overcome defects when facing the challenges of space links.

[0005] In spaceborne laser communication scenarios, the communication distance between satellites varies with orbital time, and the optimal beam divergence angle required for link establishment varies significantly at different distances. Existing technologies with no adjustable beam divergence angle or only two adjustable levels make it difficult to dynamically adjust to the optimal state based on actual distance. At long distances, if the beam divergence angle is too large, the laser energy will be excessively dispersed, resulting in insufficient signal strength and a low link establishment success rate. At closer distances, an inappropriate beam divergence angle will affect the accuracy of the beam alignment, easily leading to communication link interruptions and severely restricting the performance of spaceborne laser communication systems.

[0006] The scanning and tracking processes of laser communication equipment place distinct demands on the laser beam divergence angle. The scanning phase requires a large beam divergence to expand coverage, increase scanning speed, and quickly capture targets; the tracking phase, on the other hand, requires a small beam divergence to concentrate laser energy, improve system sensitivity, and ensure stable signal reception. Existing technologies with no adjustment or only two adjustment levels cannot flexibly switch between the two modes to achieve the ideal beam divergence angle. This results in either inefficient search during scanning due to insufficient beam divergence, or poor signal quality during tracking due to excessive beam divergence, significantly reducing the overall performance of laser communication systems.

[0007] Because existing technologies struggle to precisely adjust beam divergence to meet the demands of complex scenarios, scenarios like inter-orbit communication often rely on a super-aiming mechanism to compensate for deficiencies in beam alignment and beam divergence adaptation. This not only increases the workload of the super-aiming mechanism, requiring it to consume more energy and resources to correct deviations, but also places higher demands on its precision and stability, significantly increasing its design, manufacturing, and maintenance costs. It also increases the complexity and risk of failure of the entire laser communication system.

[0008] In summary, the existing design of fixed beam divergence angle or two-level adjustable beam divergence angle affects the performance and efficiency of the entire laser communication system, and also increases the complexity and failure risk of the entire laser communication system. Summary of the Invention

[0009] Based on this, it is necessary to provide a laser communication terminal and a beam divergence angle adjustment method that can continuously adjust the beam divergence angle in response to the above technical problems. By setting a divergence angle adjustable device in the laser communication terminal, the beam divergence angle can be continuously adjusted, and a mathematical model is established to calculate the target pitch d and the target leak-free scanning time. Solve for the optimal laser beam divergence for the final result And adjust, thereby realizing adaptive optimal beam divergence angle calculation and adjustment strategy, replacing the function of traditional precision aiming mechanism, helping to improve the performance and efficiency of the entire laser communication system, and reducing the complexity and failure risk of the entire laser communication system.

[0010] In a first aspect, the present application provides a laser communication terminal capable of continuously adjusting beam divergence angle, comprising: The transmitting optical path includes a signal light transmitting device, a divergence angle adjustable device, a plane reflector, a DM dichroic mirror and a piezoelectric fast reflector; The receiving optical path includes the BS spectrometer and the piezoelectric fast reflector and DM dichroic mirror shared with the transmitting optical path; Among them, in the transmitting optical path, the signal light transmitting device generates an initial laser signal, which is then transmitted to the DM dichroic mirror through a plane mirror after adjusting the laser beam divergence angle through a divergence angle adjustable device, and then transmitted to the piezoelectric fast reflection mirror through the DM dichroic mirror to complete the precise correction of the laser pointing before being emitted to the outside world; in the receiving optical path, the external incident laser signal passes through the piezoelectric fast reflection mirror, and then passes through the DM dichroic mirror and the BS spectrometer in turn for light energy distribution.

[0011] In one embodiment, the divergence angle adjustable device includes a liquid crystal variable focus lens.

[0012] In one embodiment, when light energy is distributed through the BS spectroscope, part of the light signal is transmitted to the tracking receiving camera, and the other part of the light signal is collimated by the receiving collimator and then converted into an electrical signal by the communication receiving module.

[0013] In a second aspect, the present application provides a beam divergence angle adjustment method, which is applied to the above-mentioned laser communication terminal, comprising: Construct a zero-leakage scanning model, and establish the camera capture sensitivity circle radius r and pitch d and zero-leakage scanning time based on the zero-leakage scanning model The mathematical model between Establishing the laser beam divergence The relationship between the radius r of the camera's capture sensitivity circle and the propagation distance s of the laser from the transmitter to the receiver; Based on the target pitch d and the target leak-free scanning time , according to the propagation distance s of the laser from the transmitter to the receiver, the optimal laser beam divergence angle is iteratively solved ; Based on the optimal laser beam divergence The beam divergence angle of the laser communication terminal is adjusted using a divergence angle adjustable device.

[0014] In one embodiment, the process of constructing a zero-missing scanning model includes: on the basis of zero-missing scanning, abstracting four time points from the scanning starting point to the stopping point and then returning to the starting point, and mapping the effective coverage area of ​​the light spot to the positions of the four time points, generating a geometric model of zero-missing scanning, and using the geometric model as the zero-missing scanning model; wherein the four time points are denoted as A, B, C and D, and the line segments AB and CD are the effective coverage widths parallel to the scanning speed direction ; Line segments AD and BC are the effective coverage width perpendicular to the scanning speed direction , that is, the pitch ; The effective coverage area radius of the light spot is r.

[0015] In one embodiment, the coarse mechanism moves at a maximum angular rate while scanning.

[0016] In one embodiment, the camera capture sensitivity circle radius r and pitch d and the non-leakage scanning time are established based on the non-leakage scanning model. The mathematical models between include: Get the scan time without missing Influencing factors, based on which, generate the zero-missing scan time The mathematical expression of the influencing factors includes the uncertainty area , signal coverage width and dwell time ; Among them, when the terminal structure is fixed, the uncertainty area is a constant; Determine signal coverage width based on the zero-missing scanning model and dwell time The relationship between the camera capture sensitivity circle radius r and the pitch d; Based on signal coverage width and dwell time The relationship between the camera capture sensitivity circle radius r and the pitch d is rewritten as the zero-missing scan time The mathematical expression of is used to generate the target mathematical model.

[0017] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the following steps are performed: Construct a zero-leakage scanning model, and establish the camera capture sensitivity circle radius r and pitch d and zero-leakage scanning time based on the zero-leakage scanning model The mathematical model between Establishing the laser beam divergence The relationship between the radius r of the camera's capture sensitivity circle and the propagation distance s of the laser from the transmitter to the receiver; Based on the target pitch d and the target leak-free scanning time , according to the propagation distance s of the laser from the transmitter to the receiver, the optimal laser beam divergence angle is iteratively solved ; Based on the optimal laser beam divergence The beam divergence angle of the laser communication terminal is adjusted using a divergence angle adjustable device.

[0018] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following steps: Construct a zero-leakage scanning model, and establish the camera capture sensitivity circle radius r and pitch d and zero-leakage scanning time based on the zero-leakage scanning model The mathematical model between Establishing the laser beam divergence The relationship between the radius r of the camera's capture sensitivity circle and the propagation distance s of the laser from the transmitter to the receiver; Based on the target pitch d and the target leak-free scanning time , according to the propagation distance s of the laser from the transmitter to the receiver, the optimal laser beam divergence angle is iteratively solved ; Based on the optimal laser beam divergence The beam divergence angle of the laser communication terminal is adjusted using a divergence angle adjustable device.

[0019] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the following steps: Construct a zero-leakage scanning model, and establish the camera capture sensitivity circle radius r and pitch d and zero-leakage scanning time based on the zero-leakage scanning model The mathematical model between Establishing the laser beam divergence The relationship between the radius r of the camera's capture sensitivity circle and the propagation distance s of the laser from the transmitter to the receiver; Based on the target pitch d and the target leak-free scanning time , according to the propagation distance s of the laser from the transmitter to the receiver, the optimal laser beam divergence angle is iteratively solved ; Based on the optimal laser beam divergence The beam divergence angle of the laser communication terminal is adjusted using a divergence angle adjustable device.

[0020] This application adopts the above-mentioned laser communication terminal capable of continuously adjusting the beam divergence angle and the beam divergence angle adjustment method, which has the following beneficial effects: 1. By setting a divergence angle adjustable device in the laser communication terminal to achieve continuous adjustment of the beam divergence angle, and establishing a mathematical model, the target pitch d and the target leak-free scanning time are used to calculate the target divergence angle. Solve for the optimal laser beam divergence for the final result And adjust, thereby realizing adaptive optimal beam divergence angle calculation and adjustment strategy, replacing the function of traditional precision aiming mechanism, helping to improve the performance and efficiency of the entire laser communication system, and reducing the complexity and failure risk of the entire laser communication system.

[0021] 2. The use of liquid crystal variable focus lens technology allows precise adjustment within any angle range based on actual needs, greatly enhancing the flexibility of laser communication terminal devices and solving the problem of continuously adjustable beam angle. Furthermore, due to its low power consumption, liquid crystal variable focus lens technology significantly reduces energy consumption while enabling complex adjustment functions. This effectively alleviates the high energy consumption problem caused by the complex systems of traditional continuously adjustable devices, reducing operating costs while also opening up the possibility of energy-sensitive applications such as satellite-based applications.

[0022] 3. By enabling continuous adjustment of the beam divergence angle, a large beam divergence angle can be flexibly used to cover the other end during inter-orbital communication, effectively compensating for the insufficient communication margin of a small beam divergence angle at long distances and with large angular deviations. The elimination of a complex over-aiming mechanism simplifies the system structure, reducing equipment weight, volume, and cost, while also minimizing the risk of failure associated with the over-aiming mechanism, improving system reliability and stability, and providing a more efficient and economical solution for inter-orbital communication scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a schematic structural diagram of a laser communication terminal capable of continuously adjusting beam divergence angle in one embodiment; Figure 2 Schematic diagram of a zero-missing scanning model in one embodiment. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0025] In a first aspect, the present application provides a laser communication terminal capable of continuously adjusting beam divergence angle, comprising: The transmitting optical path includes a signal light transmitting device, a divergence angle adjustable device, a plane reflector, a DM dichroic mirror and a piezoelectric fast reflector; The receiving optical path includes the BS spectrometer and the piezoelectric fast reflector and DM dichroic mirror shared with the transmitting optical path; Among them, in the transmitting optical path, the signal light transmitting device generates an initial laser signal, which is then transmitted to the DM dichroic mirror through a plane mirror after adjusting the laser beam divergence angle through a divergence angle adjustable device, and then transmitted to the piezoelectric fast reflection mirror through the DM dichroic mirror to complete the precise correction of the laser pointing before being emitted to the outside world; in the receiving optical path, the external incident laser signal passes through the piezoelectric fast reflection mirror, and then passes through the DM dichroic mirror and the BS spectrometer in turn for light energy distribution.

[0026] In one embodiment, the divergence angle adjustable device includes a micro-electromechanical system (MEMS) reflector array, a liquid lens, or an electrically controlled variable focus lens, preferably a liquid crystal variable focus lens among the electrically controlled variable focus lenses.

[0027] In a microelectromechanical system (MEMS) mirror array solution, multiple micro-mirror units are integrated on a silicon substrate using MEMS manufacturing processes. Each mirror can be independently controlled in angle through electrostatic, electromagnetic, or electrothermal actuation. When a laser beam is incident on the MEMS mirror array, the tilt angle of the mirror is changed to precisely control the direction of laser propagation, thereby changing the beam divergence angle.

[0028] Liquid lens solutions are primarily based on the principles of fluid mechanics and surface tension. By changing the interface shape of two immiscible liquids within the liquid lens, the focal length is continuously varied, thereby adjusting the divergence angle of the laser beam. Common drive methods include electrowetting and pneumatic drive. For example, in electrowetting liquid lenses, an electric field is applied to the liquid-solid interface, changing the surface tension of the liquid and, in turn, the curvature of the liquid lens.

[0029] In the electrically controlled variable focus lens solution, the electrically controlled variable focus lens uses special optical materials, such as liquid crystal polymers, electroactive polymers, etc., and changes the refractive index distribution of the material by applying an electric field, thereby achieving a change in the focal length of the lens, and ultimately achieving the purpose of adjusting the divergence angle of the laser beam.

[0030] The present application prefers a liquid crystal variable focus lens, which uses an electric field to precisely control the orientation of liquid crystal molecules, thereby changing the phase distribution of light when passing through the liquid crystal layer. When an external electric field is applied or a refractive index matching method is adopted, a gradient refractive index distribution is formed inside the liquid crystal layer. This distribution causes the light to focus or diverge like a lens when passing through the liquid crystal layer, thereby achieving a lens effect. Unlike traditional optical lenses, the focal length of the liquid crystal variable focus lens can be flexibly adjusted by electronic control, showing extremely high dynamics and adaptability. When the focal length of the lens changes, the beam divergence angle of the laser will also change significantly. The beam divergence angle is an important parameter to measure the degree of divergence of the laser beam during propagation, and its size directly affects the focusing ability and transmission characteristics of the laser. By precisely controlling the voltage applied to the liquid crystal variable focus lens, the focal length of the lens can be continuously adjusted, thereby making the laser beam divergence angle continuously adjustable within a certain range.

[0031] Liquid crystal variable focus lens technology is used to address the challenge of continuously adjustable beam divergence angle. Compared to conventional technologies that offer only two levels of adjustment or no adjustment at all, this invention allows precise adjustment within any angle range based on actual needs, significantly enhancing the flexibility of laser communication terminal devices. Furthermore, thanks to its low power consumption, liquid crystal variable focus lens technology significantly reduces energy consumption while enabling complex adjustment functions. This effectively alleviates the high energy consumption associated with complex systems in conventional continuously adjustable devices, reducing operating costs while also opening up potential for energy-sensitive applications such as satellite-based systems.

[0032] In one embodiment, when light energy is distributed through the BS spectroscope, part of the light signal is transmitted to the tracking receiving camera, and the other part of the light signal is collimated by the receiving collimator and then converted into an electrical signal by the communication receiving module.

[0033] For example, when distributing optical energy, 1%, 5%, 10% or 20% of the optical signal can be transmitted to the tracking receiving camera, and the remaining optical signal is transmitted to the receiving collimation head for collimation processing, and then the communication receiving module completes the conversion of the optical signal into an electrical signal.

[0034] In a second aspect, the present application provides a beam divergence angle adjustment method, which is applied to the above-mentioned laser communication terminal, comprising: S100, constructing a leak-free scanning model, and establishing the camera capture sensitivity circle radius r and pitch d and leak-free scanning time based on the leak-free scanning model The mathematical model between .

[0035] In one embodiment, the process of constructing a zero-missing scanning model includes: on the basis of zero-missing scanning, abstracting four time points from the scanning starting point to the stopping point and then returning to the starting point, and mapping the effective coverage area of ​​the light spot to the positions of the four time points, generating a geometric model of zero-missing scanning, and using the geometric model as the zero-missing scanning model; wherein the four time points are denoted as A, B, C and D, and the line segments AB and CD are the effective coverage widths parallel to the scanning speed direction ; Line segments AD and BC are the effective coverage width perpendicular to the scanning speed direction , that is, the pitch ; The effective coverage area radius of the light spot is r.

[0036] In one embodiment, the coarse mechanism moves at a maximum angular rate while scanning.

[0037] In satellite communication terminals, to achieve optimal scanning performance at different communication distances, it is necessary to ensure zero-missing scans while precisely adjusting the scanning beam divergence to minimize acquisition time. In this application, the scanning methods primarily include circular spiral scanning and square spiral scanning. The difference between these two methods lies in the shape of the scanning path: circular spiral scanning gradually expands outward along a circular trajectory, while square spiral scanning expands along a square trajectory.

[0038] Reference Figure 2 During the scanning process, scanning from point A to point B proceeds as follows: 1. Rapid movement of the coarse mechanism: The coarse mechanism (a mechanical device) moves from point A to point B at the fastest speed (maximum angular velocity). This rapid movement improves scanning efficiency and reduces unnecessary waiting time. 2. Dwell time: After reaching point B, the coarse mechanism remains at that position for a period of time (dwell time). The dwell time depends on the single exposure time of the peer camera. The camera needs sufficient time to complete a full exposure to ensure a clear image.

[0039] The angle between point A and point B is determined by the zero-missing scan step size, which refers to the angle of each scan movement to ensure that no area is missed during the scanning process. The maximum angular velocity is determined by the performance of the coarse tracking mechanism on the local end. The higher the angular velocity, the faster the movement speed from point A to point B, thereby shortening the scanning time. The dwell time is determined by the single exposure time of the camera on the other end. The length of the dwell time directly affects the scanning efficiency and image quality.

[0040] Through the above design, the scanning method of this application can maximize the scanning efficiency while ensuring scanning accuracy, ensuring fast and complete scanning effects under different scanning paths.

[0041] Reference Figure 2In the process of constructing a leak-free scanning model, this application abstracts the four time points A~D in the scanning process while ensuring leak-free scanning. The radius of the four circles are equal. Among them, the radius of the circle To meet the lower limit of the capture camera sensitivity, the effective coverage area radius of the light spot , the effective coverage area radius of the spot As the radius of the camera's capture sensitivity circle, it is related to parameters such as communication distance and laser divergence angle; line segment AB or line segment CD is the effective coverage width parallel to the scanning speed direction. ; Line segments AD and BC are the effective coverage width perpendicular to the scanning speed direction , that is, the pitch ; Line segment EF is the shortest chord length of the light spot parallel to the scanning speed direction during zero-missing scanning.

[0042] At maximum pitch During scanning, due to the limitation of the shortest chord length parallel to the scanning speed direction, the dwell time parallel to the scanning direction becomes longer, and the overall scanning time may not be optimal. Scanning, under the premise of ensuring no missed scans, the relationship between the parameters is as follows:

[0043]

[0044]

[0045] In one embodiment, the camera capture sensitivity circle radius r and pitch d and the non-leakage scanning time are established based on the non-leakage scanning model. The mathematical model between, including: obtaining the leak-free scanning time Influencing factors, based on which, generate the zero-missing scan time The mathematical expression of the influencing factors includes the uncertainty area , signal coverage width and dwell time ; Among them, when the terminal structure is fixed, the uncertainty area is a constant; based on the leak-free scanning model, the signal coverage width is determined and dwell time The relationship between the camera capture sensitivity circle radius r and the pitch d; based on the signal coverage width and dwell time The relationship between the camera capture sensitivity circle radius r and the pitch d is rewritten as the zero-missing scan time The mathematical expression of is used to generate the target mathematical model.

[0046] In satellite laser communication terminals, acquisition time refers to the time required for the line of sight to start from an arbitrary or initial position until reliable dual-end acquisition is achieved. Capture time generally includes three parts: line of sight rotation time, open-loop scanning time, and dual-end rotation tracking time. Open-loop scanning time accounts for the largest proportion, so acquisition time generally only considers open-loop scanning time. Capture time depends on the open-loop capture uncertainty area. , signal coverage width , field of view , residence time , the approximate formula for the time required to complete a scan is:

[0047] Where k is the scan overlap coefficient. In order to reduce the impact of high-frequency vibration of the visual axis on the scanning process, it is necessary to make the fields of view of two adjacent scans overlap by a certain area. The time that the capture process light spot stays on the detector; is the number of scans; The number of scanning steps required to scan the entire uncertainty area; It is the number of scanning steps to return to the center of the capture area after a scan is completed. When the number of scanning steps is large, the second item can be ignored.

[0048] Combined with zero-missing scanning geometry, effectively covers the width area . The item represents the number of scan steps after a scan ends to return to the center of the capture area. Therefore, the effective coverage width in this item is Effective coverage width parallel to the scanning speed direction The time required to complete a scan can be rewritten as:

[0049] Single dwell time It can be divided into two parts:

[0050] in, is the time it takes for the coarse mechanism to move from point A to point B at the maximum speed. Considering the process of adding and subtracting angular velocity, it is assumed that the equivalent angular velocity of moving from point A to point B is ,but ; This is the waiting time after the coarse mechanism moves to point B. It is necessary to ensure that the camera can obtain enough energy to complete the exposure of one frame of image. Since the starting dwell time of a single point may be inconsistent with the starting exposure time of a certain frame of the camera, in order to ensure that the single point dwell time at each dwell point is not less than 2 times the single exposure time of the camera ,Right now , single dwell time for:

[0051] Item 2 Indicates the time it takes to return to the scan starting point after the scan ends. When it returns to the scan starting point, it means the scan ends without waiting for the camera's exposure time. , so the second term The time required to complete a scan can be rewritten as:

[0052] Will 、 、 and Substituting into the above formula, we can get:

[0053]

[0054] in, is the scan overlap coefficient, is the uncertain area, is the equivalent angular velocity along the scanning direction, is the single exposure time, is the number of scans. When the physical device is determined, the above parameters are constant values. The camera captures the sensitivity circle radius r and pitch The above formula can be changed to:

[0055]

[0056] S200, establish laser beam divergence The relationship between the radius r of the camera capture sensitivity circle and the propagation distance s of the laser from the transmitter to the receiver.

[0057] In laser spatial light propagation systems, the relationship between the laser beam divergence angle and the camera capture sensitivity circle radius is one of the key factors in achieving effective light signal capture. This refers to the maximum angle between the edge and center rays of a laser beam during its propagation. It determines the degree of divergence of the laser beam over a specific propagation distance. The camera capture sensitivity circle radius r is the minimum radius at which the camera can effectively capture the laser signal. This radius is closely related to the camera's sensitivity and resolution.

[0058] To ensure that the laser signal can be accurately received within the effective capture range of the camera, the following relationship should be satisfied between the laser beam divergence angle and the camera capture sensitivity circle radius:

[0059] Denoted as:

[0060] in, is the divergence angle of the laser beam; r is the radius of the camera capture sensitivity circle; s is the propagation distance of the laser beam from the transmitter to the receiver.

[0061] S300, based on target pitch d and target leak-free scan time , according to the propagation distance s of the laser from the transmitter to the receiver, the optimal laser beam divergence angle is iteratively solved .

[0062] because , then in this application, if a certain pitch is known , with zero-leakage scan time If the goal is to minimize the laser beam divergence, then only the laser beam divergence angle needs to be optimized. , you can make Minimum. That is:

[0063] Based on the above, the optimal laser beam divergence angle can be solved by numerical iteration. .

[0064] S400, based on optimal laser beam divergence The beam divergence angle of the laser communication terminal is adjusted using a divergence angle adjustable device.

[0065] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0066] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0067] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0068] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like.

[0069] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A laser communication terminal capable of continuously adjusting beam divergence angle, characterized in that: include: The transmitting optical path includes a signal light transmitting device, a divergence angle adjustable device, a plane reflector, a DM dichroic mirror and a piezoelectric fast reflector; The receiving optical path includes the BS spectrometer and the piezoelectric fast reflector and DM dichroic mirror shared with the transmitting optical path; Among them, in the transmitting optical path, the signal light transmitting device generates an initial laser signal, which is then transmitted to the DM dichroic mirror through a plane mirror after adjusting the laser beam divergence angle through a divergence angle adjustable device, and then transmitted to the piezoelectric fast reflection mirror through the DM dichroic mirror to complete the precise correction of the laser pointing before being emitted to the outside world; in the receiving optical path, the external incident laser signal passes through the piezoelectric fast reflection mirror, and then passes through the DM dichroic mirror and the BS spectrometer in turn for light energy distribution.

2. The laser communication terminal according to claim 1, characterized in that: The divergence angle adjustable device comprises a liquid crystal variable focus lens.

3. The laser communication terminal according to claim 1, wherein: When light energy is distributed through the BS spectrometer, part of the light signal is transmitted to the tracking receiving camera, and the other part of the light signal is collimated by the receiving collimator head and then converted into an electrical signal by the communication receiving module.

4. A beam divergence angle adjustment method, applied to the laser communication terminal according to any one of claims 1 to 3, characterized in that: include: Construct a zero-leakage scanning model, and establish the camera capture sensitivity circle radius r and pitch d and zero-leakage scanning time based on the zero-leakage scanning model The mathematical model between Establishing the laser beam divergence The relationship between the radius r of the camera's capture sensitivity circle and the propagation distance s of the laser from the transmitter to the receiver; Based on the target pitch d and the target leak-free scanning time , according to the propagation distance s of the laser from the transmitter to the receiver, the optimal laser beam divergence angle is iteratively solved ; Based on the optimal laser beam divergence The beam divergence angle of the laser communication terminal is adjusted using a divergence angle adjustable device.

5. The method according to claim 4, characterized in that The process of constructing a zero-missing scanning model includes: on the basis of zero-missing scanning, abstracting four time points from the scanning starting point to the stopping point and then returning to the starting point, and mapping the effective coverage area of ​​the light spot to the positions of the four time points, generating a geometric model of zero-missing scanning, and using the geometric model as the zero-missing scanning model; wherein the four time points are recorded as A, B, C and D, and the line segments AB and CD are the effective coverage widths parallel to the scanning speed direction ; Line segments AD and BC are the effective coverage width perpendicular to the scanning speed direction , that is, the pitch ; The effective coverage area radius of the light spot is r.

6. The method according to claim 5, characterized in that During scanning, the coarse mechanism moves at maximum angular velocity.

7. The method according to claim 4, characterized in that The camera capture sensitivity circle radius r, pitch d and the no-leakage scanning time are established based on the no-leakage scanning model The mathematical models between include: Get the scan time without missing Influencing factors, based on which, generate the zero-missing scan time The mathematical expression of the influencing factors includes the uncertainty area , signal coverage width and dwell time ; Among them, when the terminal structure is fixed, the uncertainty area is a constant; Determine signal coverage width based on the zero-missing scanning model and dwell time The relationship between the camera capture sensitivity circle radius r and the pitch d; Based on signal coverage width and dwell time The relationship between the camera capture sensitivity circle radius r and the pitch d is rewritten as the zero-missing scan time The mathematical expression of is used to generate the target mathematical model.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 4 to 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 4 to 7 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 4 to 7 are implemented.

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