A method for adjusting the beam divergence angle

Abstract

This application relates to a beam divergence angle adjustment method, belonging to the field of laser communication technology. The device includes: a transmitting optical path, comprising a signal light emitting device, a divergence angle adjustable device, a plane mirror, a DM dichroic mirror, and a piezoelectric fast reflector; and a receiving optical path, comprising a piezoelectric fast reflector and a DM dichroic mirror shared with the transmitting optical path. The method includes constructing a no-miss scan model, establishing a mathematical model between the camera acquisition sensitivity circle radius and pitch and the no-miss scan time; establishing the relationship between the laser beam divergence angle and the camera acquisition sensitivity circle radius and laser propagation distance; and solving for the optimal laser beam divergence angle based on the target pitch and the target no-miss scan time, according to the laser propagation distance. By setting an adjustable divergence angle device and establishing a mathematical model in the laser communication terminal, an adaptive optimal beam divergence angle calculation and adjustment strategy is realized, improving system performance and efficiency, and reducing system complexity and failure risk.

Description

Technical Field

[0001] This application relates to the technical field of laser communication, and in particular to a method for adjusting beam divergence angle. Background Technology

[0002] In current mainstream spaceborne laser communication terminals, the beam divergence angle of the laser beam is usually fixed when designing the optical antenna (typically based on reflective or transmissive telescope structures such as Cassegrain or Gregorian telescopes). This means that the coverage area and spot size of the beam are determined at a specific distance.

[0003] The aiming and tracking of the beam are mainly achieved through the following methods: 1. Coarse aiming mechanism: usually based on a two-dimensional turntable, providing a wide field of view coverage for initial acquisition and a large range of angle adjustments; 2. Fine aiming mechanism: usually based on a Fast Steering Mirror (FSM) or piezoelectric ceramic actuator, providing high-precision, high-bandwidth micro-angle adjustments to compensate for platform vibration and dynamic tracking errors.

[0004] Although coarse and fine aiming mechanisms can maintain the establishment and stability of the link to a certain extent, the continuous changes in inter-satellite or satellite-to-ground distances caused by satellite orbital motion, the unavoidable vibrations (micro-vibrations) of the satellite platform itself, the limitations of attitude control accuracy, and the beam drift / spreading / flickering caused by turbulence effects when the laser descends through the atmosphere, etc., result in significant and insurmountable defects in the design of fixed beam divergence angle or two adjustable beam divergence angles when facing the challenges of space links.

[0005] In spaceborne laser communication scenarios, the communication distance between satellites varies with their orbital movement, resulting in significant differences in the optimal beam divergence angle required for link establishment at different distances. Existing technologies with non-adjustable or only two adjustable beam divergence angles struggle to dynamically adjust to the optimal state based on the actual distance. At longer distances, excessively large beam divergence angles lead to excessive dispersion of laser energy, resulting in insufficient signal strength and low link establishment success rates. Conversely, at shorter distances, inappropriate beam divergence angles can affect beam alignment accuracy, easily causing communication link interruptions and severely limiting the performance of spaceborne laser communication systems.

[0006] The requirements for laser beam divergence angle differ drastically during scanning and tracking in laser communication equipment. The scanning phase requires a large beam divergence angle to expand coverage, increase scanning speed, and quickly acquire the target; while the tracking phase requires a small beam divergence angle to concentrate laser energy, improve system sensitivity, and ensure stable signal reception. Existing technologies that are not adjustable or only have two adjustable settings cannot flexibly switch between the two modes to achieve the ideal beam divergence angle. This results in either insufficient beam divergence angle during scanning leading to low search efficiency, or excessive beam divergence angle during tracking affecting signal quality, significantly reducing the overall performance of the laser communication system.

[0007] Because existing technologies struggle to precisely adjust the beam divergence angle to meet the demands of complex scenarios, in situations such as cross-track communication, a super-alignment mechanism is often relied upon to compensate for deficiencies in beam alignment and beam divergence angle adaptation. This not only increases the workload of the super-alignment mechanism, requiring it to consume more energy and resources to correct deviations, but also places higher demands on its accuracy and stability. This leads to a significant increase in the design, manufacturing, and maintenance costs of the super-alignment mechanism, while also increasing the complexity and failure risk of the entire laser communication system.

[0008] In summary, the existing designs with fixed or two adjustable beam divergence angles affect the performance and efficiency of the entire laser communication system, while also increasing the complexity and failure risk of the entire laser communication system. Summary of the Invention

[0009] Therefore, it is necessary to provide a beam divergence angle adjustment method to address the aforementioned technical problems. This method achieves continuous adjustment of the beam divergence angle by setting an adjustable divergence angle device in the laser communication terminal, and establishes a mathematical model based on the target pitch d and the target no-miss scan time. Solve for the optimal laser beam divergence angle for the final result. It can be adjusted to achieve an adaptive optimal beam divergence angle calculation and adjustment strategy, replacing the function of the traditional precision aiming mechanism, which helps to improve the performance and efficiency of the entire laser communication system and reduce the complexity and failure risk of the entire laser communication system.

[0010] In a first aspect, this application provides a laser communication terminal with continuously adjustable beam divergence angle, comprising:

[0011] The optical transmission path includes a signal light emitting device, a divergence angle adjustable device, a plane mirror, a DM dichroic mirror, and a piezoelectric fast reflector;

[0012] The receiving optical path includes a BS beam splitter and a piezoelectric fast reflector and a DM dichroic mirror shared with the transmitting optical path;

[0013] In the transmitting optical path, the signal light emitting device generates an initial laser signal. After the divergence angle of the laser is adjusted by the divergence angle adjustable device, it is transmitted to the DM dichroic mirror through the plane mirror. Then, the laser is transmitted to the piezoelectric fast reflector through the DM dichroic mirror to complete the precise correction of the laser direction before being emitted to the outside. In the receiving optical path, the laser signal incident from the outside passes through the piezoelectric fast reflector and then passes through the DM dichroic mirror and the BS beam splitter in sequence for light energy distribution.

[0014] In one embodiment, the divergence angle adjustable device includes a liquid crystal variable focus lens.

[0015] In one embodiment, when optical energy is distributed by the BS beam splitter, a portion of the optical signal is transmitted to the tracking receiver camera, while the other portion of the optical signal is collimated by the receiving collimator and then converted into an electrical signal by the communication receiving module.

[0016] Secondly, this application provides a beam divergence angle adjustment method, applied to the aforementioned laser communication terminal, comprising:

[0017] Construct a no-miss scan model, and based on the no-miss scan model, establish the relationship between the camera capture sensitivity circle radius r and pitch d and the no-miss scan time. Mathematical models between them;

[0018] Establish laser beam divergence The relationship between the camera's capture sensitivity circle radius r and the laser propagation distance s from the transmitter to the receiver;

[0019] Based on the target pitch d, with no missed scan time The goal is to minimize the laser beam divergence angle by iteratively solving for the optimal laser beam divergence angle based on the propagation distance *s* of the laser beam from the transmitter to the receiver. ;

[0020] Based on the optimal laser beam divergence angle The beam divergence angle of the laser communication terminal can be adjusted using a divergence angle adjustable device.

[0021] In one embodiment, the process of constructing a no-miss scan model includes: based on no-miss scan, abstracting four time points from the scanning start point to the dwell point and back to the start point, and mapping the effective coverage area of ​​the light spot to the positions of the four time points to generate a no-miss scan geometric model, which is then used as the no-miss scan model; wherein, the four time points are denoted as A, B, C, and D, and line segments AB and CD are the effective coverage widths parallel to the scanning speed direction. Line segments AD and BC represent the effective coverage width perpendicular to the scanning speed direction. pitch The effective coverage area radius of the light spot is r.

[0022] In one embodiment, the coarse mechanism moves at its maximum angular rate during scanning.

[0023] In one embodiment, the camera capture sensitivity circle radius r and pitch d are established in relation to the no-miss scan time based on the no-miss scan model. The mathematical models between them include:

[0024] Obtaining the time of no missed scans Influencing factors, and generating a no-miss scan time based on these influencing factors. The mathematical expression; the influencing factors include the uncertain region. Signal coverage width and length of stay Among them, when the terminal structure is fixed, the uncertain region It is a constant;

[0025] Determine the signal coverage width based on the no-miss scan model. and length of stay The relationship between the camera capture sensitivity circle radius r and the pitch d;

[0026] Based on signal coverage width and length of stay Rewriting the relationship between camera capture sensitivity, circle radius r, and pitch d to rewrite the no-miss scan time The mathematical expression is used to generate the target mathematical model.

[0027] Thirdly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to perform the following steps:

[0028] Construct a no-miss scan model, and based on the no-miss scan model, establish the relationship between the camera capture sensitivity circle radius r and pitch d and the no-miss scan time. Mathematical models between them;

[0029] Establish laser beam divergence The relationship between the camera's capture sensitivity circle radius r and the laser propagation distance s from the transmitter to the receiver;

[0030] Based on the target pitch d, with no missed scan time The goal is to minimize the laser beam divergence angle by iteratively solving for the optimal laser beam divergence angle based on the propagation distance *s* of the laser beam from the transmitter to the receiver. ;

[0031] Based on the optimal laser beam divergence angle The beam divergence angle of the laser communication terminal can be adjusted using a divergence angle adjustable device.

[0032] Fourthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, performs the following steps:

[0033] Construct a no-miss scan model, and based on the no-miss scan model, establish the relationship between the camera capture sensitivity circle radius r and pitch d and the no-miss scan time. Mathematical models between them;

[0034] Establish laser beam divergence The relationship between the camera's capture sensitivity circle radius r and the laser propagation distance s from the transmitter to the receiver;

[0035] Based on the target pitch d, with no missed scan time The goal is to minimize the laser beam divergence angle by iteratively solving for the optimal laser beam divergence angle based on the propagation distance *s* of the laser beam from the transmitter to the receiver. ;

[0036] Based on the optimal laser beam divergence angle The beam divergence angle of the laser communication terminal can be adjusted using a divergence angle adjustable device.

[0037] Fifthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, performs the following steps:

[0038] Construct a no-miss scan model, and based on the no-miss scan model, establish the relationship between the camera capture sensitivity circle radius r and pitch d and the no-miss scan time. Mathematical models between them;

[0039] Establish laser beam divergence The relationship between the camera's capture sensitivity circle radius r and the laser propagation distance s from the transmitter to the receiver;

[0040] Based on the target pitch d, with no missed scan time The goal is to minimize the laser beam divergence angle by iteratively solving for the optimal laser beam divergence angle based on the propagation distance *s* of the laser beam from the transmitter to the receiver. ;

[0041] Based on the optimal laser beam divergence angle The beam divergence angle of the laser communication terminal can be adjusted using a divergence angle adjustable device.

[0042] This application employs the above-mentioned method for adjusting the beam divergence angle, which has the following beneficial effects:

[0043] 1. By setting an adjustable divergence angle device in the laser communication terminal, the beam divergence angle can be continuously adjusted, and a mathematical model is established, taking the target pitch d and the target no-miss scan time as the basis. Solve for the optimal laser beam divergence angle for the final result. It can be adjusted to achieve an adaptive optimal beam divergence angle calculation and adjustment strategy, replacing the function of the traditional precision aiming mechanism, which helps to improve the performance and efficiency of the entire laser communication system and reduce the complexity and failure risk of the entire laser communication system.

[0044] 2. Employing liquid crystal variable focus lens technology, precise adjustment within any angle range is possible according to actual needs, greatly enhancing the flexibility of laser communication terminal devices and solving the problem of continuously adjustable beam divergence angle. Simultaneously, the liquid crystal variable focus lens technology, with its low power consumption, significantly reduces energy consumption while achieving complex adjustment functions. This effectively alleviates the high energy consumption problem caused by the complex systems of traditional continuously adjustable devices, reducing operating costs and enabling applications in energy-sensitive scenarios such as spaceborne systems.

[0045] 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-track communication, effectively compensating for the insufficient communication margin of a small beam divergence angle under long-distance and large-angle deviation conditions. The elimination of complex overshoot mechanisms simplifies the system structure, reduces equipment weight, size, and cost, and also reduces the risk of failure caused by overshoot mechanisms, improving system reliability and stability, and providing a more efficient and economical solution for inter-track communication scenarios. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of a laser communication terminal with continuously adjustable beam divergence angle in one embodiment;

[0047] Figure 2 This is a schematic diagram of a no-miss scan model in one embodiment. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0049] In a first aspect, this application provides a laser communication terminal with continuously adjustable beam divergence angle, comprising:

[0050] The optical transmission path includes a signal light emitting device, a divergence angle adjustable device, a plane mirror, a DM dichroic mirror, and a piezoelectric fast reflector;

[0051] The receiving optical path includes a BS beam splitter and a piezoelectric fast reflector and a DM dichroic mirror shared with the transmitting optical path;

[0052] In the transmitting optical path, the signal light emitting device generates an initial laser signal. After the divergence angle of the laser is adjusted by the divergence angle adjustable device, it is transmitted to the DM dichroic mirror through the plane mirror. Then, the laser is transmitted to the piezoelectric fast reflector through the DM dichroic mirror to complete the precise correction of the laser direction before being emitted to the outside. In the receiving optical path, the laser signal incident from the outside passes through the piezoelectric fast reflector and then passes through the DM dichroic mirror and the BS beam splitter in sequence for light energy distribution.

[0053] In one embodiment, the divergence angle adjustable device includes a microelectromechanical system (MEMS) mirror array, a liquid lens, or an electrically controlled variable focus lens. Preferably, it is a liquid crystal variable focus lens among electrically controlled variable focus lenses.

[0054] In the microelectromechanical system (MEMS) mirror array scheme, multiple miniature mirror units are integrated on a silicon substrate using MEMS manufacturing processes. Each mirror can be independently controlled in terms of angle via electrostatic, electromagnetic, or electrothermal actuation. When a laser beam is incident on the MEMS mirror array, the direction of laser propagation can be precisely controlled by changing the tilt angle of the mirrors, thereby altering the beam divergence angle.

[0055] In liquid lens schemes, the liquid lens is mainly based on the principles of fluid mechanics and surface tension. By changing the shape of the interface between two immiscible liquids within the liquid lens, the focal length can be continuously varied, thereby adjusting the beam divergence angle of the laser beam. Common driving methods include electrowetting and pneumatic actuation. Taking an electrowetting liquid lens as an example, an electric field is applied to the liquid-solid interface, changing the surface tension of the liquid and thus altering the curvature of the liquid lens.

[0056] In the electrically controlled variable focus lens scheme, the electrically controlled variable focus lens uses special optical materials, such as liquid crystal polymers and electroactive polymers. By applying an electric field to change the refractive index distribution of the material, the focal length of the lens is changed, thereby achieving the purpose of adjusting the laser beam divergence angle.

[0057] This application preferably utilizes a liquid crystal variable focus lens, which precisely controls the orientation of liquid crystal molecules using an electric field, thereby altering the phase distribution of light as it passes through the liquid crystal layer. When an external electric field is applied or refractive index matching is employed, a gradient refractive index distribution forms within the liquid crystal layer. This distribution causes light to focus or diverge like a lens when passing through the liquid crystal layer, achieving a lens effect. Unlike traditional optical lenses, the focal length of the liquid crystal variable focus lens can be flexibly adjusted electronically, exhibiting extremely high dynamism and adaptability. When the focal length of the lens changes, the beam divergence angle of the laser also changes significantly. The beam divergence angle is an important parameter measuring the degree of divergence of a laser beam during propagation, and its magnitude directly affects the focusing ability and transmission characteristics of the laser. By precisely controlling the voltage applied to the liquid crystal variable focus lens, continuous adjustment of the lens focal length can be achieved, thus enabling continuous adjustment of the laser beam divergence angle within a certain range.

[0058] By employing liquid crystal variable focus lens technology, the challenge of continuously adjustable beam divergence angle is solved. Compared to traditional technologies that can only achieve two levels of adjustment or are not adjustable at all, this invention can precisely adjust within any angle range according to actual needs, greatly improving the flexibility of laser communication terminal devices. Simultaneously, the liquid crystal variable focus lens technology, with its low power consumption characteristics, significantly reduces energy consumption while achieving complex adjustment functions. This effectively alleviates the high energy consumption problem caused by the complex systems of traditional continuously adjustable devices, reducing operating costs and enabling applications in energy-sensitive scenarios such as spaceborne systems.

[0059] In one embodiment, when optical energy is distributed by the BS beam splitter, a portion of the optical signal is transmitted to the tracking receiver camera, while the other portion of the optical signal is collimated by the receiving collimator and then converted into an electrical signal by the communication receiving module.

[0060] For example, when distributing light energy, 1%, 5%, 10%, or 20% of the light signal can be transmitted to the tracking receiver camera, and the remaining light signal can be transmitted to the receiving collimator for collimation processing, and then the communication receiving module can complete the conversion of the light signal into an electrical signal.

[0061] Secondly, this application provides a beam divergence angle adjustment method, applied to the aforementioned laser communication terminal, comprising:

[0062] S100, Construct a no-miss scan model, and based on the no-miss scan model, establish the relationship between the camera capture sensitivity circle radius r and pitch d and the no-miss scan time. The mathematical model between them.

[0063] In one embodiment, the process of constructing a no-miss scan model includes: based on no-miss scan, abstracting four time points from the scanning start point to the dwell point and back to the start point, and mapping the effective coverage area of ​​the light spot to the positions of the four time points to generate a no-miss scan geometric model, which is then used as the no-miss scan model; wherein, the four time points are denoted as A, B, C, and D, and line segments AB and CD are the effective coverage widths parallel to the scanning speed direction. Line segments AD and BC represent the effective coverage width perpendicular to the scanning speed direction. pitch The effective coverage area radius of the light spot is r.

[0064] In one embodiment, the coarse mechanism moves at its maximum angular rate during scanning.

[0065] In spaceborne communication terminals, to achieve optimal scanning performance at different communication distances, it is necessary to minimize the acquisition time by precisely adjusting the scan beam divergence angle while ensuring no missed scans. In this application, the scanning methods mainly 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 expands outwards gradually along a circular trajectory, while square spiral scanning expands along a square trajectory.

[0066] Reference Figure 2In the specific scanning process, the scanning method from point A to point B is 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 rate). The purpose of this rapid movement is to improve scanning efficiency and reduce unnecessary waiting time; 2. Dwell time: After reaching point B, the coarse mechanism will remain at that position for a period of time (dwell time). The length of the dwell time depends on the single exposure time of the opposite camera. The camera needs sufficient time to complete a full exposure to ensure a clear image is obtained.

[0067] The angle from point A to point B is determined by the scan step size, which is the angle of movement for each scan to ensure that no area is missed during the scan. The maximum angular rate is determined by the performance of the local coarse tracking mechanism. The higher the angular rate, the faster the movement from point A to point B, thus shortening the scan time. The dwell time is determined by the single exposure time of the remote camera. The length of the dwell time directly affects the scanning efficiency and image quality.

[0068] Through the above design, the scanning method of this application can maximize scanning efficiency while ensuring scanning accuracy, and ensure that a fast and complete scanning effect can be achieved under different scanning paths.

[0069] Reference Figure 2 In constructing the no-miss scan model, this application abstracts four time points A~D during the scanning process, while ensuring no missed scans, and defines the radii of four circles. All are equal. Among them, the radius of the circle... To meet the lower limit of the camera's sensitivity, the effective coverage area radius of the light spot is... The effective coverage area radius of the light spot The radius of the camera's capture sensitivity circle is related to parameters such as communication distance and laser divergence angle; line segment AB or line segment CD represents the effective coverage width parallel to the scanning speed direction. Line segments AD and BC represent the effective coverage width perpendicular to the scanning speed direction. pitch The line segment EF is the shortest chord length of the light spot parallel to the scanning speed direction when there is no missed scan.

[0070] With 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. Assuming arbitrary pitch... The scan was performed, and the relationships between the parameters are as follows, assuming no missed scans:

[0071]

[0072]

[0073]

[0074] In one embodiment, the camera capture sensitivity circle radius r and pitch d are established in relation to the no-miss scan time based on the no-miss scan model. The mathematical model between them includes: obtaining the no-miss scan time Influencing factors, and generating a no-miss scan time based on these influencing factors. The mathematical expression; the influencing factors include the uncertain region. Signal coverage width and length of stay Among them, when the terminal structure is fixed, the uncertain region The signal coverage width is determined based on a no-miss scan model and is a constant. and length of stay The relationship between the camera capture sensitivity circle radius r and pitch d; based on signal coverage width and length of stay Rewriting the relationship between camera capture sensitivity, circle radius r, and pitch d to rewrite the no-miss scan time The mathematical expression is used to generate the target mathematical model.

[0075] In spaceborne laser communication terminals, acquisition time refers to the time required for reliable two-end acquisition from any or initial position of the line of sight. Acquisition time typically includes three parts: line-of-sight turning time, open-loop scan time, and two-end turning and tracking. Among these, the open-loop scan time accounts for the largest proportion; therefore, the acquisition time usually only considers the open-loop scan time. The acquisition time depends on the uncertainty area of ​​the open-loop acquisition. Signal coverage width Field of view Duration of stay The approximate formula for the time required to complete one scan is:

[0076]

[0077] Where k is the scanning overlap coefficient. In order to reduce the impact of high-frequency vibration of the visual axis on the scanning process, the fields of view of two adjacent scans need to overlap by a certain area. This refers to the time the light spot remains on the detector during the capture process; Number of scans; The number of scan steps required to scan the entire uncertain region; This is the number of scan steps required to return to the center of the captured area after a single scan. When the number of scan steps is large, the second item can be ignored.

[0078] By combining the geometric relationship of no missing scans, the width area can be effectively covered. . This term represents the number of scan steps required to return to the center of the captured area after a single scan; therefore, the effective coverage width in this term... Effective coverage width parallel to the scan velocity direction They are equal. The formula for the time required to complete one scan can be rewritten as:

[0079]

[0080] Duration of stay per visit It can be divided into two parts:

[0081]

[0082] in, Let's consider the time it takes for the coarse mechanism to move from point A to point B at its maximum speed, taking into account the process of adding and subtracting angular velocities. Assume the equivalent angular velocity from point A to point B is... ,but ; The dwell time after the coarse mechanism moves to point B must ensure that the camera acquires enough energy to expose one frame of the image. Since the initial dwell time at a single point may differ from the initial exposure time of a single frame, the dwell time at each point must be at least twice the camera's single exposure time to guarantee that the dwell time at each point is not less than twice the camera's single exposure time. ,Right now Duration of stay per visit for:

[0083]

[0084] Second item This indicates the time it takes for the scan to return to the starting point. Once the scan returns to the starting point, the scan is complete, and there is no need to wait for the camera's exposure time. Therefore, in the second item The formula for the time required to complete one scan can be rewritten as:

[0085]

[0086] Will , , and Substituting into the above equation, we get:

[0087]

[0088]

[0089] in, For the scanning overlap coefficient, For uncertain regions, The equivalent angular velocity along the scanning velocity direction, For single exposure time, Number of scans. All parameters are constants assuming the physical equipment is fixed. No-miss scan time. With camera capture sensitivity circle radius r and pitch Related. The above formula can be changed to:

[0090]

[0091]

[0092] S200, establish laser beam divergence angle The relationship between the camera's capture sensitivity circle radius r and the laser propagation distance s from the transmitter to the receiver.

[0093] In laser spatial light propagation systems, the relationship between the laser beam divergence angle and the radius of the camera's acquisition sensitivity circle is one of the key factors for achieving effective optical signal acquisition. (Laser beam divergence angle) The angle between the edge rays and the central ray of a laser beam during propagation is the maximum angle between them, determining the degree of divergence of the laser beam over a specific propagation distance. The camera capture sensitivity circle radius *r* refers to the minimum radius at which a camera can effectively capture a laser signal; this radius is closely related to the camera's sensitivity and resolution.

[0094] 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 radius of the camera's capture sensitivity circle:

[0095]

[0096] Recorded as:

[0097]

[0098] in, denoted as the laser beam divergence angle; r is the radius of the camera's capture sensitivity circle; and s is the propagation distance of the laser beam from the transmitter to the receiver.

[0099] S300, based on the target pitch d, with no missed scan time The goal is to minimize the laser beam divergence angle by iteratively solving for the optimal laser beam divergence angle based on the propagation distance *s* of the laser beam from the transmitter to the receiver. .

[0100] because In this application, if a certain pitch is known... With no missed scan time If minimizing is the objective, then only the laser beam divergence angle needs to be optimized. That can make Minimum. That is:

[0101]

[0102] Based on the above, the optimal laser beam divergence angle can be solved using numerical iteration. .

[0103] S400, based on optimal laser beam divergence angle The beam divergence angle of the laser communication terminal can be adjusted using a divergence angle adjustable device.

[0104] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0105] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0106] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0107] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, 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 many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for adjusting the beam divergence angle, characterized in that, include: Construct a no-miss scan model, and based on the no-miss scan model, establish the relationship between the camera capture sensitivity circle radius r and pitch d and the no-miss scan time. Mathematical model between them; Establish laser beam divergence The relationship between the camera's capture sensitivity circle radius r and the laser propagation distance s from the transmitter to the receiver; Based on the target pitch d, with no missed scan time The goal is to minimize the laser beam divergence angle by iteratively solving for the optimal laser beam divergence angle based on the propagation distance *s* of the laser beam from the transmitter to the receiver. ; Based on the optimal laser beam divergence angle The beam divergence angle of the laser communication terminal can be adjusted using a divergence angle adjustable device; The laser communication terminal includes: a transmitting optical path, comprising a signal light emitting device, a divergence angle adjustable device, a plane mirror, a DM dichroic mirror, and a piezoelectric fast reflector; and a receiving optical path, comprising a BS beam splitter and a piezoelectric fast reflector and a DM dichroic mirror shared with the transmitting optical path. In the transmitting optical path, the signal light emitting device generates an initial laser signal, which is then transmitted to the DM dichroic mirror via the plane mirror after the divergence angle adjustable device is adjusted. The DM dichroic mirror then transmits the laser signal to the piezoelectric fast reflector for precise laser pointing correction before transmitting it to the outside. In the receiving optical path, the laser signal incident from the outside passes through the piezoelectric fast reflector and then sequentially passes through the DM dichroic mirror and the BS beam splitter for light energy distribution.

2. The method according to claim 1, characterized in that, The divergence angle adjustable device includes a liquid crystal variable focus lens.

3. The method according to claim 1, characterized in that, When optical energy is distributed through the BS beam splitter, part of the optical signal is transmitted to the tracking receiver camera, while the other part of the optical signal is collimated by the receiving collimator and then converted into an electrical signal by the communication receiving module.

4. The method according to claim 1, characterized in that, The process of constructing a no-miss scan model includes: based on no-miss scan, abstracting four time points from the scanning start point to the dwell point and back to the start point, and mapping the effective coverage area of ​​the light spot to the positions of the four time points to generate a no-miss scan geometric model, which is then used as the no-miss scan model; where the four time points are denoted as A, B, C, and D, and line segments AB and CD are the effective coverage widths parallel to the scanning speed direction. Line segments AD and BC represent the effective coverage width perpendicular to the scanning speed direction. pitch The effective coverage area radius of the light spot is r.

5. The method according to claim 4, characterized in that, During scanning, the coarse mechanism moves at its maximum angular velocity.

6. The method according to claim 1, characterized in that, Based on the no-miss scan model, the camera acquisition sensitivity circle radius r and pitch d are correlated with the no-miss scan time. The mathematical models between them include: Obtaining the time of no missed scans Influencing factors, and generating a no-miss scan time based on these influencing factors. The mathematical expression; the influencing factors include the uncertain region. Signal coverage width and length of stay Among them, when the terminal structure is fixed, the uncertain region It is a constant; Determine the signal coverage width based on the no-miss scan model. and length of stay The relationship between the camera capture sensitivity circle radius r and the pitch d; Based on signal coverage width and length of stay Rewriting the relationship between camera capture sensitivity, circle radius r, and pitch d to rewrite the no-miss scan time The mathematical expression is used to generate the target mathematical model.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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