A method and system for on-orbit self-calibration of stellar images using lasers based on voice coil self-driven technology.

Abstract

This invention provides a method and system for on-orbit self-calibration of stellar laser images based on voice coil self-drive. It employs a voice coil motor to directly drive a fast-reflecting mirror or lens assembly, achieving micron-level high-precision and rapid adjustment of the laser optical path. The method uses a star sensor to capture stellar light spots in real time, calculates the centroid offset of the optical axis, forms a stellar image feedback closed loop, and drives the voice coil motor in real time for dynamic compensation, achieving integrated automatic calibration of "sensing, calculation, and execution." Compared with traditional solutions, this invention can shorten the calibration response time to the microsecond level and significantly increase the calibration frequency to over 100Hz, making it highly adaptable to high-dynamic low-Earth orbit remote sensing satellite platforms and meeting the requirements for rapid and accurate laser pointing calibration. This method innovatively replaces mechanical transmission with a voice coil-driven optical path, combined with image closed-loop feedback, to achieve high-frequency, high-precision, and low-latency stellar laser self-calibration.

Description

Technical Field

[0001] This invention relates to the field of automatic laser pointing calibration technology, specifically to an on-orbit self-calibration method and system for stellar image lasers based on voice coil self-drive. Background Technology

[0002] With the widespread deployment of high-precision laser applications such as space laser communication, laser ranging, and lidar on low-Earth orbit (LEO) remote sensing satellites, the requirements for laser pointing accuracy and real-time calibration capabilities are increasingly stringent. Traditional laser optical path calibration methods often employ mechanical transmission structures, such as stepper motors, worm gears, and lead screws, to drive fast-reflecting mirrors (FSMs) or lens groups to adjust the optical path. These mechanical transmission methods suffer from significant drawbacks, including slow response speed, complex structure, susceptibility to wear, and high maintenance difficulty. Their typical response time is usually in the millisecond range, making it difficult to meet the real-time, high-frequency adjustment requirements for laser pointing in highly dynamic and rapidly changing environments. For example, during the flight of a LEO remote sensing satellite, the laser pointing needs to dynamically follow changes in the satellite's attitude and orbit. If the calibration frequency and response speed are insufficient, the laser beam can easily deviate from the target, affecting mission accuracy and reliability.

[0003] Furthermore, traditional calibration systems often employ open-loop control, adjusting the optical path based on preset commands or single measurement results, lacking real-time sensing and closed-loop correction of actual optical axis deviations. This approach easily accumulates errors and leads to calibration failure when mechanical backlashes or environmental disturbances (such as temperature drift or structural deformation) are present. While some high-end systems have introduced optical feedback or attitude sensors for compensation, their calibration speed and accuracy remain limited by the dynamic performance of the mechanical components.

[0004] In recent years, voice coil motors (VCMs), as brushless, frictionless, and extremely fast linear drive devices, have demonstrated significant advantages in the field of precision optical adjustment. VCMs can achieve position adjustments at the micrometer or even nanometer level, with response times down to the microsecond level, and are compact and highly reliable. Applying VCMs to laser optical path adjustment can greatly improve the speed and accuracy of optical path adjustment, solving problems such as hysteresis, backlash, and fragility inherent in mechanical transmission structures.

[0005] Meanwhile, the star sensor, as a high-precision attitude measurement device, can capture stellar images in real time and output sub-pixel-level stellar barycentric coordinates. Integrating the star sensor into the laser calibration system enables real-time perception of the deviation between the laser axis and the stellar target, providing precise feedback for closed-loop control. Based on the "perception-computation-execution" closed-loop framework, the system can dynamically perceive stellar spot shifts at high frequencies and drive the voice coil motor in real time for compensation, effectively combating laser pointing errors caused by satellite attitude changes and mechanical disturbances.

[0006] In summary, existing technologies have the following main shortcomings in automatic laser pointing calibration: (1) The mechanical transmission structure has a slow response speed, which makes it difficult to meet the real-time adjustment requirements of the laser pointing of the high dynamic satellite platform; (2) Traditional systems are mostly open-loop control, lacking real-time sensing and closed-loop correction of laser optical axis deviation, which easily leads to cumulative errors; (3) The calibration frequency is limited by mechanical and control systems, making it difficult to break through 10~20 Hz, and cannot adapt to high dynamic application scenarios of 100 Hz and above; (4) The structure is complex, easily worn, and has insufficient long-term reliability, which increases maintenance costs and system risks.

[0007] Therefore, there is an urgent need to develop a high-frequency, high-precision laser self-calibration method based on voice coil direct drive and closed-loop feedback of stellar images to meet the urgent needs of the new generation of high-dynamic low-Earth orbit remote sensing satellites for rapid, accurate, and automatic laser pointing calibration.

[0008] Patent application CN119595018A discloses a fully automated star calibration method for a ground-based photoelectric telescope, comprising: constructing a star list for calibration in the star map corresponding to the current moment; traversing the stars in the star list, and determining whether the deviation between the telescope's current azimuth and elevation real-time positions and the position of the currently guided star is within a first threshold, based on the currently guided star; when within the first threshold, acquiring the centroid position of the currently guided star through an image acquisition system, and determining the miss distance of the currently guided star based on the centroid position; the telescope control system calculating the miss distance variance based on the miss distance, and determining whether the miss distance variance is within a second threshold; when the miss distance variance is within the second threshold, saving the calibration data of the guided star, and moving to the next star for automatic calibration, until all stars in the star list have been traversed. However, this patent cannot completely solve the existing technical problems, nor can it meet the needs of this invention. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide an on-orbit self-calibration method and system for stellar image lasers based on voice coil self-drive.

[0010] The on-orbit self-calibration method for stellar image lasers based on voice coil self-driven technology provided by the present invention includes: Step S1: Acquire stellar images of the target area for calibration, and capture stellar spot information using a star sensor; Step S2: Process the captured star image in real time, calculate the centroid coordinates of the star spot, and obtain the deviation between the current laser axis and the target star coordinates; Step S3: Input the deviation into the control algorithm to generate compensation commands; Step S4: Directly drive the fast-reflecting mirror or lens group with a voice coil motor to adjust the laser optical path and achieve micron-level displacement compensation; Step S5: Repeat the process of acquiring stellar images, calculating deviations, and adjusting the voice coil drive to form a closed-loop feedback until the optical axis deviation meets the preset calibration accuracy requirements; Step S6: Output the final calibrated laser optical path state to achieve stellar laser self-calibration.

[0011] Preferably, the star sensor is connected to the image processing and control unit via a high-speed data interface, transmitting the raw image data to the control unit in real time. After processing by an algorithm, the image processing and control unit sends the generated compensation command to the voice coil motor via an analog voltage signal or a digital communication interface. Upon receiving the command, the voice coil motor outputs a corresponding current or voltage to drive the fast-reflecting mirror or lens group to move. The closed-loop feedback is implemented by the internal software of the image processing and control unit, forming a closed loop consisting of image acquisition, deviation calculation, command generation, motor drive, and optical path adjustment.

[0012] Preferably, the voice coil motor applies the received voltage / current command to the coil of the voice coil motor, generating an electromagnetic force proportional to the current. Where B is the magnetic field strength, I is the current, and L is the effective length of the coil; the electromagnetic force directly drives the fast-reflecting mirror to rotate around its axis through a flexible hinge or rigid connection, or drives the lens group to translate along the optical axis; the rotation angle of the fast-reflecting mirror... The relationship with electromagnetic force is determined through structural stiffness model calibration, satisfying... ,in This is the stiffness coefficient.

[0013] Preferably, the centroid coordinates are calculated using a sub-pixel-level image processing algorithm. First, the grayscale image acquired by the star sensor is denoised, and an adaptive threshold is set to segment the target spot region. Then, the centroid coordinates are calculated using the grayscale centroid method, with the following formula:

[0014] in, The coordinates of the center of mass of the star's spot are given. Where N represents the grayscale value of the corresponding pixel, and N is the total number of pixels involved in the calculation. Let be the coordinates of the i-th pixel; Gaussian surface fitting is performed on the light spot region, and a two-dimensional Gaussian function is fitted using the least squares method. The coordinates of the fitting center are used as the final centroid coordinates.

[0015] Preferably, the current centroid coordinates of the stellar spot are compared with the preset target coordinates of the laser beam axis to obtain the real-time deviation between the laser beam path and the target star. Let the ideal centroid coordinates of the target star be... The current actual centroid coordinates are Then the optical axis deviation .

[0016] Preferably, in step S3, the deviation is input to the real-time control algorithm, and an optimal compensation command is generated based on the system dynamics characteristics and the current deviation magnitude; the control unit calculates the control output according to the PID formula based on the current deviation.

[0017] in, This is the proportionality coefficient. The integral coefficient is... The differential coefficients are... This is the real-time deviation. The rate of change of the deviation will ultimately control the output. Convert to voltage or current command values.

[0018] Preferably, the system coordinates the star sensor exposure time, image processing time, and voice coil motor drive time through a unified clock signal or synchronization pulse.

[0019] Preferably, the voice coil motor and the fast-reflecting mirror or lens group are connected by a rigid or flexible connection, and the fast-reflecting mirror is a two-degree-of-freedom or multi-degree-of-freedom miniature reflector.

[0020] The on-orbit self-calibration system for stellar image lasers based on voice coil self-drive provided by the present invention includes: A laser emitting unit, used to generate a laser beam; A voice coil motor-driven fast-reflecting mirror or lens group, wherein the voice coil motor and the fast-reflecting mirror or lens group are rigidly or flexibly connected, and the voice coil motor is used to directly drive the fast-reflecting mirror or lens group to adjust the laser optical path; The star sensor unit is installed coaxially with the optical path or the laser emission direction to capture star images in real time and output sub-pixel level centroid coordinates of the star spot; The image processing and control computing unit is connected to the star sensor unit through a high-speed data interface. It is used to process the image output by the star sensor in real time, including star spot recognition, centroid extraction, coordinate calculation, deviation analysis, and generating control compensation commands in real time based on the deviation. A closed-loop feedback control system is used to realize closed-loop control of star map perception, calculation, voice coil drive, and optical path adjustment. The data acquisition and communication interface is used for data interaction between various units within the system, as well as for interconnection with external systems for satellite attitude management and mission scheduling.

[0021] Preferably, the optical output port of the laser emitting unit is aligned with the optical incident surface of the fast reflector or the lens group to form an optical path channel; the star sensor unit is coaxially or parallel to the laser emitting unit; the voice coil motor is directly mechanically connected to the fast reflector or the lens group through a rigid or flexible coupling.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The voice coil motor is used to directly drive the fast-reflecting mirror or lens group, eliminating the complex mechanical transmission link and shortening the response time of optical path adjustment from the millisecond level of the traditional solution to the microsecond level (the response time of the voice coil motor is less than 100 microseconds), thereby meeting the high-precision pointing requirements in high dynamic and rapidly changing scenarios. (2) Through the high-frequency closed-loop feedback link of “image acquisition → deviation calculation → command generation → motor drive → optical path adjustment”, the system can achieve a closed-loop calibration frequency of more than 100Hz, which far exceeds the upper limit of 10~20Hz of the traditional calibration method, and is suitable for high dynamic attitude change scenarios such as low-orbit remote sensing satellites. (3) The coordinates of the centroid of the star spot are calculated by using a sub-pixel level image processing algorithm (gray-scale centroid method + Gaussian surface fitting). Combined with the micron-level displacement compensation of the voice coil motor, the laser pointing error is controlled within a very small range (calibration accuracy is better than 5 microns), which effectively overcomes the gap and hysteresis problems of mechanical transmission. (4) The voice coil direct drive scheme simplifies the mechanical structure, reduces moving parts and vulnerable parts, avoids the wear problems of stepper motors, worm gears and other transmission methods, improves the overall reliability and failure resistance of the system, and reduces long-term operation and maintenance costs; (5) Based on the closed-loop feedback of the star sensor, the automatic calibration of "sensing-computation-execution" is realized without manual intervention. It can continuously and automatically correct the optical axis deviation caused by changes in satellite attitude, structural deformation, temperature drift, etc., and avoid the cumulative error that is easy to be generated by open-loop control. Attached Figure Description

[0023] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart of the on-orbit self-calibration method for stellar images based on voice coil self-driven lasers according to the present invention. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0025] Example like Figure 1 This invention provides an on-orbit self-calibration method for stellar images using lasers based on voice coil self-driven technology, comprising the following steps: Step S1: Acquire stellar images of the target area for calibration, and capture stellar spot information using a star sensor; Step S2: Process the captured star image in real time, calculate the centroid coordinates of the star spot, and obtain the deviation between the current laser axis and the target star coordinates; Step S3: Input the deviation into the control algorithm to generate compensation commands; Step S4: Directly drive the fast-reflecting mirror or lens group with a voice coil motor to adjust the laser optical path and achieve micron-level displacement compensation; Step S5: Repeat the process of acquiring stellar images, calculating deviations, and adjusting the voice coil drive to form a closed-loop feedback until the optical axis deviation meets the preset calibration accuracy requirements; Step S6: Output the final calibrated laser optical path state to achieve high-frequency, high-precision stellar laser self-calibration.

[0026] The voice coil motor has a response time of less than 100 microseconds to enable rapid adjustment of the laser optical path.

[0027] The fast-reflecting mirror is a two- or multi-degree-of-freedom miniature mirror used for fine adjustment of the laser emission direction.

[0028] The centroid coordinates are calculated using a sub-pixel-level image processing algorithm to improve the accuracy of spot position detection.

[0029] The closed-loop feedback frequency is greater than 100Hz, which is used to adapt to environmental changes of the high-dynamic low-Earth orbit remote sensing satellite platform.

[0030] During the calibration process, the multi-target recognition capability of the star sensor is utilized to achieve parallel tracking and calibration of multiple star spots.

[0031] The voice coil motor is connected to the fast-reflecting mirror or lens assembly using a rigid or flexible connection to ensure the adjustment response speed and accuracy.

[0032] The calibration accuracy is better than 5 micrometers, which can meet the requirements of high-precision laser pointing.

[0033] This invention addresses the prominent problems of slow response speed, limited accuracy, and complex maintenance in existing laser calibration technologies by proposing an on-orbit self-calibration method and system for stellar images based on voice coil self-drive. This method innovatively integrates direct-drive optical path adjustment by a voice coil motor with closed-loop feedback from stellar images, establishing a high-frequency, high-precision automatic laser calibration system that integrates sensing, computing, and execution. This significantly improves the real-time performance, accuracy, and system reliability of laser pointing, making it particularly suitable for the rapid, automatic, and precise laser pointing calibration requirements of high-dynamic, low-Earth orbit remote sensing satellite platforms.

[0034] The main concept of this invention lies in using a voice coil motor (VCM) to directly drive a fast-steering mirror (FSM) or lens assembly, replacing the traditional mechanical transmission structure, to achieve micron-level and nanosecond-level rapid adjustment of the laser optical path. Compared with indirect mechanical transmissions such as stepper motors and worm gears, voice coil motors have inherent advantages such as frictionless operation, backlash-free operation, compact structure, and fast response speed. This can shorten the response time for optical path adjustment from milliseconds to microseconds, greatly improving the dynamic performance and service life of the system.

[0035] Building upon this foundation, this invention introduces a star sensor as an external high-precision reference. By capturing images of the target star's light spot, it achieves real-time sensing of laser optical axis deviation. Specifically, the star sensor captures images of stars in the target region, calculates the centroid coordinates of the star's light spot using an image processing algorithm, and then compares these coordinates with the laser design target in real time to obtain the optical axis offset. This offset serves as the input for closed-loop control. A real-time control algorithm (such as PID or adaptive compensation algorithm) generates compensation commands, driving a voice coil motor to adjust the fast-reflecting mirror or lens group, dynamically correcting the laser optical path and achieving closed-loop self-calibration.

[0036] The workflow of this invention is as follows: (1) After the system is started, the star sensor continuously captures images of the target star and extracts the centroid coordinates of the star spot through a high-precision image processing algorithm to achieve real-time measurement at the sub-pixel level. (2) Compare the current centroid coordinates of the star spot with the design target coordinates of the laser beam axis to calculate the real-time deviation of the beam axis; (3) Input the deviation into the real-time control algorithm to generate accurate compensation commands; (4) The voice coil motor directly drives the fast-reflecting mirror or lens group according to the compensation command to realize the rapid adjustment of the laser optical path and compensate for the optical axis deviation; (5) The above steps are executed repeatedly at high frequency to form a closed-loop feedback link for calculating the deviation of the centroid measurement of the star image and adjusting the voice coil-driven optical path, thereby realizing high dynamic, automatic and real-time calibration of the laser pointing.

[0037] This invention has the following significant technical advantages and innovations: 1. Voice coil direct drive, microsecond-level response By directly driving the optical adjustment unit with a voice coil motor, the complex mechanical transmission link is eliminated, greatly reducing structural inertia and motion hysteresis. The voice coil motor can achieve micron-level or even nanometer-level position adjustment with a response time of less than 100 microseconds, which is significantly better than traditional mechanical methods such as stepper motors and worm gears. It can effectively adapt to laser pointing deviations caused by rapid changes in satellite attitude and orbital disturbances.

[0038] 2. Closed-loop feedback for stellar image processing, sub-pixel level self-calibration By acquiring images of stars using a star sensor and employing sub-pixel-level image processing algorithms to extract the centroid coordinates of starlight spots in real time, high-precision sensing of laser optical axis deviation is achieved. Image information is then fed back to the control loop, forming a closed-loop structure of "perception, computation, and execution," significantly improving calibration accuracy and robustness. This allows for continuous and automatic correction of errors introduced by satellite dynamics, structural deformation, and environmental drift.

[0039] 3. High calibration frequency, suitable for high dynamic applications The system can achieve a closed-loop calibration frequency higher than 100Hz, far exceeding the 10~20Hz upper limit of traditional calibration methods, meeting the high-precision laser pointing calibration requirements of high dynamic and high-frequency attitude adjustment scenarios such as low-orbit remote sensing satellites.

[0040] 4. Simplified structure and high reliability The voice coil direct-drive solution significantly simplifies the mechanical structure, reduces moving parts and vulnerable components, and improves the overall reliability and resilience of the system. At the same time, it extends maintenance cycles and reduces long-term operating costs, making it suitable for long-term, high-reliability applications in space.

[0041] 5. Easy to integrate and expand The method of this invention has a compact structure and is easy to integrate with existing laser communication, laser ranging, space remote sensing and other systems. It can also be expanded to parallel calibration of multiple targets and multiple optical paths as needed, thereby improving mission adaptability.

[0042] 6. Supports multi-objective parallel self-calibration By leveraging the multi-target recognition capability of the star sensor, the system can simultaneously identify and track multiple star spots, enabling parallel automatic calibration of multi-path laser pointing, further enhancing system efficiency and capability limits.

[0043] 7. High-precision, long-term stable operation This invention effectively suppresses long-term drift factors such as mechanical aging and environmental changes through closed-loop control and real-time compensation, ensuring the high precision and long-term stability of laser pointing.

[0044] The system of this invention mainly includes: 1. Laser emitting unit, used to generate a high-quality laser beam; 2. A voice coil motor-driven fast-reflecting mirror or lens assembly enables high-precision and rapid adjustment of the laser optical path; 3. Star sensor, used to capture stellar images and output sub-pixel level stellar barycentric coordinates; 4. Real-time image processing and control unit, responsible for star spot recognition, centroid extraction, optical axis deviation calculation and compensation command generation; 5. Closed-loop feedback control system to achieve high-frequency dynamic self-calibration of the system.

[0045] I. System Composition Structure The system device of the present invention mainly includes the following parts: 1. Laser emitting unit: generates a highly stable and highly directional laser beam, which can be used for space missions such as laser communication, ranging, and laser pointing control; 2. Fast mirror (FSM) or adjustable lens group: As an optical path adjustment component, it is used to change the spatial orientation of the laser beam to achieve high-precision angle or position fine adjustment within a small range; 3. Voice coil motor (VCM) drive unit: directly drives the fast-reflecting mirror or lens group to achieve high response speed, micron-level or even nanometer-level adjustment of the laser beam direction; 4. Star sensor unit: Installed coaxially in the optical path or laser emission direction, used to capture star images in real time and output sub-pixel level centroid coordinates of star spots; 5. Image processing and control unit: responsible for real-time processing of images output by the star sensor, including star spot recognition, centroid extraction, coordinate calculation, deviation analysis, and generating control compensation commands in real time based on the deviation. 6. Closed-loop feedback control system: used to realize closed-loop control of star map perception, calculation, voice coil drive and optical path adjustment, and realize high-frequency automatic self-calibration; 7. Data Acquisition and Communication Interface: Used for efficient data interaction between various units within the system, as well as interconnection with external systems such as satellite attitude management and mission scheduling.

[0046] The connection and signal transmission relationships between the above components are as follows: (1) Mechanical connection: The voice coil motor is directly mechanically connected to the fast reflector or lens group through a rigid or flexible coupling to ensure backlash-free transmission; the optical output port of the laser emitting unit is aligned with the optical incident surface of the fast reflector or lens group to form an optical path channel; the star sensor unit is coaxially or parallel to the laser emitting unit to ensure that the star observation reference is consistent with the laser optical axis.

[0047] (2) Electrical connection and signal flow: The star sensor unit is connected to the image processing and control unit through a high-speed data interface, and transmits the raw image data to the control unit in real time; after the image processing and control unit processes the data by the algorithm, it sends the generated compensation command to the voice coil motor through an analog voltage signal or a digital communication interface; after receiving the command, the voice coil motor outputs the corresponding current or voltage to drive the fast-reflecting mirror or lens group to move; the closed-loop feedback control system is implemented by the internal software of the image processing and control unit, forming a closed loop of "image acquisition → deviation calculation → command generation → motor drive → optical path adjustment"; the data acquisition and communication interface is connected to the image processing unit and the external satellite system respectively, and is used for status reporting and task coordination.

[0048] (3) Timing synchronization: The system coordinates the exposure time of the star sensor, the image processing time and the voice coil motor driving time through a unified clock signal or synchronization pulse to ensure the time determinism of closed-loop control.

[0049] II. Implementation Process The implementation process of this invention can be divided into the following key steps: 1. Initialization and Self-Test 1) After the system is powered on, it first performs a self-test on the core components such as the laser emitting unit, voice coil motor, fast reflector, and star sensor to ensure that each component is working properly.

[0050] 2) The control unit loads parameters such as the target star region, target accuracy, and maximum permissible deviation for this calibration task.

[0051] 2. Stellar Image Acquisition 1) The star sensor observes a designated area of ​​the sky and acquires images of stars.

[0052] 2) The image processing algorithm automatically identifies the target star, extracts the star's light spot, and calculates its sub-pixel-level centroid coordinates.

[0053] The specific calculation process for sub-pixel level centroid coordinates is as follows: First, the grayscale image acquired by the star sensor is denoised, and an adaptive threshold is set to segment the target spot area; then, the centroid coordinates are calculated using the grayscale centroid method, with the following formula:

[0054] in The coordinates of the center of mass of the star's spot are given. This corresponds to the pixel grayscale value. To further improve accuracy, a Gaussian surface is fitted to the spot area. A two-dimensional Gaussian function is fitted using the least squares method, and the coordinates of the fitted center are used as the final centroid coordinates, achieving sub-pixel level positioning accuracy.

[0055] 3. Calculation of optical axis deviation The control unit compares the current centroid coordinates of the stellar spot with the preset target coordinates of the laser beam axis to obtain the real-time deviation (usually a two-dimensional or three-dimensional offset) between the laser beam path and the target star. Let the ideal centroid coordinates of the target star be... The current actual centroid coordinates are Then the optical axis deviation .

[0056] 4. Compensation instruction generation 1) The deviation is input to a real-time control algorithm (such as PID, adaptive control, etc.), which generates an optimal compensation command based on the system dynamics and the current deviation magnitude. The control unit calculates the control output according to the PID formula based on the current deviation:

[0057] in, The parameters, whether preset or adaptively tuned, will ultimately control the quantity. Convert to voltage or current command values.

[0058] 2) The compensation command is converted into a current or voltage drive signal for the voice coil motor, which precisely controls the adjustment direction and amplitude of the fast-reflecting mirror or lens group.

[0059] 5. Voice coil drive and optical path adjustment 1) Upon receiving a compensation command, the voice coil motor rapidly drives the fast-reflecting mirror or lens assembly to make micron-level angle / position adjustments, achieving rapid correction of the laser optical path. The received voltage / current command is applied to the voice coil motor coil, generating an electromagnetic force proportional to the current. ( The magnetic field strength, (This refers to the effective length of the coil). This force directly drives the fast-reflecting mirror to rotate around its axis via a flexible hinge or rigid connection, or drives the lens group to translate along the optical axis. The rotation angle of the fast-reflecting mirror. The relationship between electromagnetic force and structural stiffness is determined by a structural stiffness model and generally satisfies the following conditions: ,in This refers to the stiffness coefficient. The control unit uses closed-loop compensation to ensure the fast-reflecting mirror accurately reaches the target angle, achieving micron-level or sub-arcsecond-level adjustment of the laser beam direction. During the adjustment process, a position sensor provides real-time feedback on the lens position, forming an inner position loop to further improve adjustment accuracy.

[0060] 2) Due to the extremely low structural inertia and extremely high dynamic response capability of the voice coil motor, the adjustment process can be completed within tens to hundreds of microseconds.

[0061] 6. Closed-loop feedback and self-calibration 1) After adjustment, the star sensor acquires star images again, and the control unit recalculates the deviation between the center of mass position and the optical axis.

[0062] 2) The closed-loop feedback control system continuously cycles through the above acquisition, calculation, and adjustment process at a frequency of 100Hz or even higher until the optical axis deviation is less than the preset threshold, thus completing this self-calibration.

[0063] 7. Output and archiving of calibration results The system outputs the final calibration status, optical axis adjustment amount, laser pointing accuracy and other results to the data management unit, and archives the relevant operating data for reuse in subsequent tasks or for fault analysis.

[0064] III. Key Technical Details 1. Coupling design of voice coil motor driving fast-reflecting mirror 1) Select a voice coil motor with high thrust density, low electrical noise and high stability, and integrate it with a fast-reflecting mirror or lens group through flexible or rigid connection to ensure gapless movement and short response time.

[0065] 2) Structural optimization design ensures that the system is compact as a whole and the mechanical resonance frequency is much higher than the control bandwidth, thereby improving dynamic performance and anti-disturbance capability.

[0066] 2. Subpixel-level centroid extraction algorithm 1) High-precision image processing algorithms (such as Gaussian fitting, centroid method, interpolation method, etc.) are used to identify and locate stellar light spots at the sub-pixel level, effectively improving the accuracy of optical axis deviation measurement.

[0067] 2) Supports multi-target recognition and tracking, enabling parallel calibration capabilities for multi-beam laser or multi-target satellite pointing.

[0068] 3. High-frequency closed-loop control strategy 1) The control system uses a high-bandwidth digital controller for closed-loop compensation based on the real-time output of the star sensor, ensuring that even in highly dynamic disturbance environments (such as rapid attitude changes of low-orbit satellites, micro-vibrations, etc.), the system can still complete compensation and adjustment in a very short time.

[0069] 2) Control parameters can be adaptively adjusted online to adapt to different task conditions and environmental changes.

[0070] 4. Multi-scenario adaptability and self-diagnostic function 1) The system supports flexible switching of control strategies and calibration parameters according to different orbits, attitudes, and purposes, thereby improving versatility and task adaptability.

[0071] 2) Built-in self-diagnosis and self-recovery mechanism to monitor the working status of key components (such as voice coil motor, fast reflector, star sensor, etc.) in real time. When abnormal, it can automatically alarm and switch to safe mode.

[0072] IV. Specific Application Examples Example 1: Calibration of Laser Communication for Low-Earth Orbit Remote Sensing Satellites A low-Earth orbit remote sensing satellite is equipped with the voice coil-driven stellar laser self-calibration system described in this invention. During the satellite's in-orbit flight, due to attitude disturbances and orbital changes, the pointing of the laser communication terminal needs to be adjusted in real time. The system captures stellar images through a star sensor, calculates the optical axis deviation in real time, and uses a voice coil motor to drive a fast-reflecting mirror to continuously fine-tune at a frequency of 100Hz, ensuring that the laser beam is always accurately aligned with the ground receiving station, greatly improving the stability and effective time of the communication link.

[0073] Example 2: Space Laser Ranging and Pointing Self-Calibration In space laser ranging missions, the laser pointing accuracy is required to be better than 5 micrometers. The system uses a self-calibration process, a star sensor feedback closed loop, and a voice coil motor driving a fast-reflecting mirror to control the laser pointing error within 2 micrometers, achieving high-precision space ranging and target tracking.

[0074] V. Implementation Results and Advantages Compared with traditional mechanical transmission calibration systems, the embodiments of the present invention exhibit the following significant advantages in practical engineering applications: 1) Significantly reduced response time: The voice coil motor direct drive structure reduces the response time from milliseconds to microseconds, making it suitable for high dynamic and rapid adjustment requirements; 2) Significantly improved calibration frequency: The closed-loop control frequency can reach 100Hz and above, meeting the high dynamic attitude change scenarios of low-orbit satellites; 3) Improved calibration accuracy: Subpixel-level image processing and micron-level voice coil adjustment ensure that the optical axis deviation is within an extremely small range; 4) Improved system reliability and lifespan: Simplified mechanical structure, reduced vulnerable parts, high long-term operational reliability, and low maintenance costs; 5) High degree of automation: The entire process is closed-loop automatic calibration without manual intervention, and supports multi-target parallel calibration and adaptive adjustment.

[0075] In summary, through the above specific embodiments, this invention achieves high-frequency, high-precision, and automated self-calibration of laser pointing in a highly dynamic space environment, fully meeting the application needs of cutting-edge fields such as next-generation space laser remote sensing and communication, and has broad practical application prospects and promotional value.

[0076] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0077] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for on-orbit self-calibration of a star image laser based on a voice coil self-drive, characterized in that, include: Step S1: Acquire stellar images of the target area for calibration, and capture stellar spot information using a star sensor; Step S2: Process the captured star image in real time, calculate the centroid coordinates of the star spot, and obtain the deviation between the current laser axis and the target star coordinates; Step S3: Input the deviation into the control algorithm to generate compensation commands; Step S4: Directly drive the fast-reflecting mirror or lens group with a voice coil motor to adjust the laser optical path and achieve micron-level displacement compensation; Step S5: Repeat the process of acquiring stellar images, calculating deviations, and adjusting the voice coil drive to form a closed-loop feedback until the optical axis deviation meets the preset calibration accuracy requirements; Step S6: Output the final calibrated laser optical path state to achieve stellar laser self-calibration.

2. The self-calibration method of star image laser on-orbit based on self-driven voice coil according to claim 1, characterized in that, The star sensor is connected to the image processing and control unit via a high-speed data interface, transmitting the raw image data to the control unit in real time. After processing by the algorithm, the image processing and control unit sends the generated compensation command to the voice coil motor via an analog voltage signal or a digital communication interface. Upon receiving the command, the voice coil motor outputs a corresponding current or voltage to drive the fast-reflecting mirror or lens group to move. The closed-loop feedback is implemented by the internal software of the image processing and control unit, forming a closed loop of image acquisition, deviation calculation, command generation, motor drive, and optical path adjustment in sequence.

3. The self-calibration method of star image laser on-orbit based on self-driven voice coil, according to claim 2, characterized in that, The voice coil motor receives the voltage / current command and acts on the coil of the voice coil motor to generate an electromagnetic force proportional to the current Where B is the magnetic field strength, I is the current, and L is the effective length of the coil; the electromagnetic force directly drives the fast mirror to rotate around its axis through a flexible hinge or rigid connection, or drives the lens group to translate along the optical axis; the rotation angle of the fast mirror The relationship between the electromagnetic force and the rotation angle of the fast mirror is calibrated through a structural stiffness model, satisfying Where is the stiffness coefficient.

4. The self-calibration method of star image laser on-orbit based on self-driven voice coil according to claim 1, characterized in that, The centroid coordinates are calculated using a sub-pixel-level image processing algorithm. First, the grayscale image acquired by the star sensor is denoised, and an adaptive threshold is set to segment the target spot region. Then, the centroid coordinates are calculated using the grayscale centroid method, with the following formula: wherein, is the coordinate of the centroid of the stellar faculae, is the corresponding pixel gray value, N is the total number of pixels participating in the calculation, is the coordinate of the i-th pixel; Gaussian surface fitting is performed on the light spot region, and a two-dimensional Gaussian function is fitted using the least squares method. The coordinates of the fitting center are used as the final centroid coordinates.

5. The self-calibration method of star image laser on-orbit based on voice coil self-driving according to claim 4, characterized in that, The current star light spot center coordinate is compared with the preset laser optical axis target coordinate to obtain a real-time deviation amount between the laser light path and the target star. The ideal center coordinate of the target star is , the current actual center coordinate is , and the optical axis deviation amount is .

6. The self-calibration method of star image laser on-orbit based on self-driven voice coil according to claim 1, characterized in that, In step S3, the deviation is input to the real-time control algorithm, which generates an optimal compensation command based on the system dynamics and the current deviation magnitude; the control unit calculates the control output according to the PID formula based on the current deviation. wherein, is a proportional coefficient, is an integral coefficient, is a derivative coefficient, is a real-time deviation amount, is a rate of change of the deviation, eventually converting the control output amount into a voltage or current command value.

7. The self-calibration method of star image laser on-orbit based on self-driven voice coil according to claim 1, characterized in that, The system coordinates the star sensor exposure time, image processing time, and voice coil motor drive time through a unified clock signal or synchronization pulse.

8. The self-calibration method of star image laser on-orbit based on self-driven voice coil according to claim 1, characterized in that, The voice coil motor is rigidly or flexibly connected to the fast-reflecting mirror or lens group, and the fast-reflecting mirror is a two-degree-of-freedom or multi-degree-of-freedom miniature mirror.

9. A self-driven star image laser on-orbit self-calibration system based on a voice coil, characterized in that, The method for on-orbit self-calibration of stellar images using lasers based on voice coil self-drive, as described in any one of claims 1 to 8, includes: A laser emitting unit, used to generate a laser beam; A voice coil motor-driven fast-reflecting mirror or lens group, wherein the voice coil motor and the fast-reflecting mirror or lens group are rigidly or flexibly connected, and the voice coil motor is used to directly drive the fast-reflecting mirror or lens group to adjust the laser optical path; The star sensor unit is installed coaxially with the optical path or the laser emission direction to capture star images in real time and output sub-pixel level centroid coordinates of the star spot; The image processing and control computing unit is connected to the star sensor unit through a high-speed data interface. It is used to process the image output by the star sensor in real time, including star spot recognition, centroid extraction, coordinate calculation, deviation analysis, and generating control compensation commands in real time based on the deviation. A closed-loop feedback control system is used to realize the closed-loop control of star map sensing-computing-voice coil driving-optical path adjustment. A data acquisition and communication interface is used for data interaction between the units in the system and interconnection and intercommunication with the external systems of satellite attitude management and task scheduling.

10. The self-calibration system for star image laser on-orbit according to claim 9, characterized in that, The optical output port of the laser emitting unit is aligned with the optical incident surface of the fast mirror or the lens group to form an optical path channel; the star sensor unit is coaxial or parallel with the laser emitting unit; the voice coil motor is directly mechanically connected with the fast mirror or the lens group through a rigid or flexible coupling.

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