69 results about "Pointing error" patented technology

The invention relates to the technical field of satellite attitude control, in particular to a satellite-borne laser semi-autonomous pointing control method, electronic equipment and a storage medium. The method is completed by cooperation of a ground system and an on-satellite system, the ground system calculates a top target passing moment T * in advance, generates a unified laser pointing control instruction and injects the instruction into a satellite; and the satellite-borne system receives and analyzes the instruction, obtains parameters such as T * and beam selection, and then autonomously controls a specified load for work preparation. And the satellite-borne system autonomously calculates the optimal moment T1 and the target attitude when passing through the calibration field through high-precision orbit extrapolation based on the latest navigation data, finally autonomously executes attitude maneuver and laser pointing tasks, and autonomously returns after the tasks are completed. Instructions in a uniform format are generated and injected from the ground, ground operation is greatly simplified, efficient cooperation of ground decision triggering and on-satellite autonomous execution is achieved, pointing errors caused by orbit extrapolation are greatly reduced, the pointing precision and the task success rate are improved, and universality is good.

The invention relates to the technical field of space telescope calibration, in particular to a telescope pointing calibration method based on optical fiber interconnection, which comprises the following steps: providing reference light beams in different directions, enabling each lens to correspondingly receive the reference light beams by adjusting the lens pointing, splitting the reference light beams received by the lenses through an optical splitter, and obtaining a split beam; one beam is aligned and corrected through a camera, and the other beam is coupled into an optical fiber to record direction information; the calibration light beams are reversely emitted by the optical fiber through the optical switch and are emitted by the lens, each reference light beam in the known direction is reproduced, a reference light field is formed, the telescope to be calibrated is placed in the reference light field, the miss distance of each calibration light beam in the known direction on the mirror surface of the telescope to be calibrated is measured, and the pointing error is calculated and corrected according to the miss distance. The optical fiber network is used for establishing the unique mapping relation between the space direction and the optical fiber channel, miss distance measurement is carried out through dynamic time-sharing reproduction, and the problems of mechanical accumulative errors and the like existing in a traditional mechanical calibration method are solved.

The invention provides a laser terminal calibration method and system based on inter-satellite orbit mutual transmission, and the method comprises the steps: carrying out the static calibration of a laser terminal through employing a star sensor or ground assistance before the establishment of an inter-satellite communication link, and enabling the pointing error of an optical axis to be smaller than 0.1 degree; after a communication link is established, orbit parameters of two satellites are exchanged in real time, a relative orbit normal vector is calculated through coordinate transformation, and a fusion reference is dynamically generated in combination with a static calibration result. According to the method, the real-time track mutual transmission data is used as dynamic correction input, the initial static calibration result is not only relied on any more, and fusion benchmark optimization of calibration and track mutual transmission is achieved. Compared with a traditional static calibration method depending on a ground station or a single-star inertial reference, the method breaks through the precision bottleneck of static calibration through the fusion of the orbit dynamic data and the static calibration result, effectively eliminates the orbit dynamic error, improves the laser calibration precision to a micro-radian level, and improves the calibration precision. And the establishment efficiency and reliability of the inter-satellite laser link are greatly improved.

The invention discloses a ground station antenna pointing error compensation method and related equipment. The method comprises the following steps: controlling an antenna driving shaft to sequentially rotate to a plurality of measuring points according to a preset angle step length in a preset angle range, and synchronously acquiring a command angle value output by an encoder and an actual angle value output by a gradienter at each measuring point; for each measurement point, an error value is calculated according to the relation that the error value is equal to the difference between the actual angle value and the command angle value, and an error sample set containing a plurality of data pairs is formed; and performing curve fitting processing on the error sample set to obtain a continuous and smooth error compensation function in the preset angle range, and performing ground station antenna pointing error compensation by using the error compensation function, the error compensation function being used for representing a mapping relationship between a command angle value and an error value. The problem that an existing ground station antenna pointing error compensation method is high in cost, complex in implementation or limited in compensation effect can be solved.

The application discloses a kind of mechanical hand eye automatic calibration method, device, equipment and medium, comprising: obtaining calibration board image and identifying feature point and camera field of view center, select target feature point and record first mechanical hand coordinates and initial pixel coordinates;Control mechanical hand moves fixed step along multiple directions and obtains tentative information, and determine target mechanical hand coordinates and step length adjustment mode accordingly;According to iterative update mechanical hand coordinates and fixed step according to alignment condition, establish the corresponding relationship of final mechanical hand coordinates and initial pixel coordinates;Repeat the above operation to the rest feature points, calculate hand-eye transformation relationship based on multiple sets of corresponding relationship.The application gradually corrects the position of mechanical hand by the iterative alignment mode driven by pixel error, and realizes stable convergence by combining step length adjustment, so as to reduce the point error of artificial, improve calibration accuracy, reduce repeated adjustment process, and improve calibration efficiency.

The invention discloses a horizon astronomical telescope pointing error correction method based on machine learning. The method comprises the following steps: recording fixed star data; constructing a telescope rack pointing model, calculating a model coefficient, performing coarse correction on a new observation target, accumulating observation data, and preprocessing the observation data; training the preprocessed training set data by using an XGBoost regression model, predicting condition parameters of a new observation target by using a trained error prediction model to obtain normalized azimuth angle deviation and elevation angle deviation predicted values of the new observation target, and carrying out reverse normalization processing on the predicted values to obtain an actual rack deviation angle; and superposing the rough correction deviation angle and the actual rack deviation angle to serve as a final offset to be injected into a telescope rack tracking program so as to realize correction of a pointing error. According to the invention, the pointing error can be within a very small range, and the pointing precision of the horizon telescope can be effectively improved.

The invention belongs to the technical field of heliostat measurement, and particularly relates to a method for measuring the pointing error of a heliostat by using moonlight and a camera, which comprises the following steps: rotating the heliostat, and guiding the moonlight reflected by the heliostat to the camera; detecting the actual rotation angle of the heliostat when the center of the reflected light beam is located at the camera position; meanwhile, the theoretical rotation angle of the heliostat at the position is calculated based on the heliostat coordinates, the camera coordinates and the moonlight azimuth vector; the difference between the actual rotation angle and the theoretical rotation angle is the pointing error of the heliostat at the current position. The method has the advantages that the moon orientation naturally changes along with time, infinite measurement orientations can be provided theoretically, an unmanned aerial vehicle or an additional calibration tower is not needed, and therefore the system cost is remarkably reduced.

This application relates to the field of human eye gaze estimation technology, and provides a self-calibration method, apparatus, device, and medium for human eye gaze deviation parameters. Since the final gaze predicted in this application's embodiments is based on a gaze unrelated to the user's identity (i.e., the initial gaze) and a gaze related to the user's identity (i.e., the human eye gaze deviation parameters), and these parameters can be continuously optimized during user use, this application's embodiments can improve the accuracy of gaze estimation. Furthermore, since this application's embodiments perform gradient backpropagation based on intersection point error loss, i.e., using the geometric constraints of the gaze as a supervision signal, this application's embodiments do not require separate collection of the user's gaze label samples before the user uses the gaze estimation system. Instead, the human eye gaze deviation parameters can be continuously learned during user use, and as the number of samples increases, the human eye gaze deviation parameters will become increasingly accurate.

The invention provides a pointing error correction method and device of a beam waveguide system, equipment and a storage medium, which can be applied to the technical field of antennas. The method comprises the following steps: acquiring laser incident to a beam waveguide system along a current beam transmission direction every time an antenna rotates to an angle; laser is reflected to the target through first to Sth plane mirrors in the beam waveguide system, a first laser point is obtained, and the first to Sth plane mirrors are plane mirrors which are closer to the target in sequence; determining an angle error according to the first laser point, the second laser point incident to the Sth plane mirror and the target point; rotating angles of waveguide reflectors are adjusted, angle errors are corrected, the waveguide reflectors are used for reflecting a current wave beam, and a plane mirror is placed in the center of each waveguide reflector; re-acquiring the first laser point, and determining a displacement error according to the re-acquired first laser point and the target point; and adjusting the displacement of the waveguide reflector, and correcting the displacement error.

The application belongs to the technical field of heliostat measurement, and particularly relates to a method for measuring pointing error of heliostat by using moonlight and a camera, comprising the following steps: rotating the heliostat, guiding the moonlight reflected by the heliostat to the camera; detecting the actual rotation angle of the heliostat when the center of the reflected light beam is located at the position of the camera; at the same time, calculating the theoretical rotation angle of the heliostat at the position based on the heliostat coordinates, the camera coordinates and the moonlight azimuth vector; the difference between the actual rotation angle and the theoretical rotation angle is the pointing error of the heliostat at the current position. The method has the advantages that the moon azimuth changes naturally with time, theoretically, infinite measurement azimuths can be provided, and an unmanned aerial vehicle or an additional calibration tower is not needed, so that the system cost is significantly reduced.

The application belongs to the technical field of space exploration imaging, and provides an imaging instrument view direction calibration method, comprising the following steps: obtaining a calibration image and identifying a target star point to find a predicted view line pointing center; obtaining a calibration view line pointing center of the imaging instrument in the calibration image and calculating a center pointing error; calculating lens parameters and star point fitting errors of the imaging instrument; generating an azimuth angle grid and an elevation angle grid of the lens view line pointing, and calculating a center pointing error and a star point fitting error of each grid point formed by the azimuth angle grid and the elevation angle grid to form a dispersion matrix and a fitting error matrix respectively; calculating a normalized goodness matrix and determining a lens optimized pointing. The method can realize accurate calibration of the imaging instrument lens pointing and lens parameters without knowing the lens view line center pointing, does not need to consider the lens field of view size, corrects the error caused by the imaging instrument pointing deviation, and improves the measurement accuracy.

The present application relates to the technical field of altazimuth telescope, in particular to a pointing model calibration method of altazimuth telescope, the error function of the telescope is obtained by two-dimensional surface fitting, the star image is shot every 10 degrees or so in the azimuth and elevation directions, the right ascension and declination of the image center are obtained by comparing with the standard star map, the right ascension and declination are converted into the real azimuth and real elevation in the geodetic horizontal coordinate according to the shooting time, the geographical longitude and latitude of the telescope, the altitude, the air temperature and air pressure; the real azimuth and real elevation are subtracted by the azimuth and elevation read by the angle sensor of the telescope respectively, the azimuth error matrix and the elevation error matrix are obtained respectively; the error matrix is fitted to obtain the azimuth error function, the real azimuth and real elevation of any target are subtracted by the azimuth pointing error and the elevation pointing error respectively, and the accurate pointing of the telescope can be obtained.

The present application relates to a kind of motion coupling under spaceborne laser communication terminal fixed time disturbance control method, for the periscope type laser communication terminal fast pointing control problem under the influence of multi-source disturbance such as space environment interference, floating satellite platform coupling moment and rotation shaft friction moment, first, the deep coupling model of spaceborne communication terminal containing above-mentioned multi-source disturbance is established, and multi-source disturbance is regarded as total disturbance moment by analyzing interference structure and characteristics;Second, fixed time disturbance observer is designed to quickly estimate the total disturbance moment suffered by communication terminal;Third, nominal fixed time controller is designed and combined with disturbance observer to form fixed time compound anti-interference controller;Finally, combined with the pointing time demand of communication terminal, observer and controller parameter selection are analyzed and guided, and fixed time anti-interference control of spaceborne laser communication terminal under motion coupling is completed.The control method of the present application has the characteristics of strong robustness, fast pointing speed and guaranteeing pointing error fixed time convergence.

The application discloses a target radar cross section estimation method and system, and relates to the technical field of radio and radar detection; the method comprises the following steps: forming a main scanning beam, a left accompanying beam and a right accompanying beam in a residence period, collecting echo samples to obtain an echo sample set, recording a beam serial number and a pointing angle to obtain a multi-beam pointing table, and obtaining a multi-beam power group from the echo intensity of three beams; obtaining a direction map deviation segment from the multi-beam power group and the multi-beam pointing table; aligning the direction map deviation segment with the echo sample set, and obtaining a channel consistency correction table according to a background echo segment; obtaining a de-drift echo power sequence and a maneuvering decoupling weight according to the channel consistency correction table and a tracking error sequence; the application can effectively solve the problems of the mixing of sidelobe energy caused by the beam pointing error in the prior art and the asymmetric drift of the radar cross section estimation caused by the change of the beam shape with the pointing.

A kind of full strapdown millimeter wave phased array radar system pointing calibration method, main steps include: to be calibrated system is installed on three-axis turntable, based on the set calibration range and calibration granularity, calculate t time antenna azimuth beam pointing angle and elevation beam pointing angle theoretical value, and corresponding turntable attitude angle theoretical value, control turntable turns to the angle;Adjust phased array antenna beam pointing, so that target is located in the antenna beam center, obtain the actual value of antenna azimuth beam pointing angle and elevation beam pointing angle at this time, with the difference between the beam pointing theoretical value and actual value as the pointing error of phased array at the angle, to complete the calibration test of all angles in calibration range.This is a kind of high-efficiency calibration test method at system level, without accurately determining the coordinate position of each array element of antenna, can take into account the influence of system each link error on beam pointing precision, realize the fast, high-precision high-speed full strapdown millimeter wave phased array test calibration.

The invention provides a spacecraft double-flywheel under-actuated sun safety control method and system, and the method comprises the steps: S1, calculating a sun quaternion according to the time of a GNC computer system of a spacecraft, and calculating a sun error quaternion according to the quaternion from a spacecraft inertial system to the system; s2, calculating a sun target angular velocity according to the sun error quaternion and the inertial angular velocity of the gyroscope of the spacecraft; s3, calculating a double-flywheel under-actuated sun control quantity according to the inertial angular velocity of the spacecraft gyroscope and the sun target angular velocity; and S4, open-loop processing is carried out on spacecraft double-flywheel under-actuated sun control according to the sun error quaternion, the control torque is prevented from exceeding the maximum torque provided by the flywheels, and low-pass filtering is carried out on the control torque. According to the invention, stable sun alignment under the double-flywheel configuration of the spacecraft actuating mechanism is realized, and the energy safety of the spacecraft is effectively guaranteed.

The invention belongs to the technical field of astronomical observation equipment, and particularly relates to a modeling and correcting method and system for static pointing errors of a horizontal telescope. The method comprises the following steps: S1, establishing a horizontal telescope static pointing model, and analyzing shafting error factors of the telescope; s2, deducing a telescope shafting static pointing error compensation model based on the static pointing model; s3, substituting experimental data, fitting the data by using a least square method, and determining each undetermined coefficient of the compensation model; and S4, correcting the static pointing error of the warp axis and the weft axis of the telescope by using the compensation model. The method has the characteristics that the observation precision can be improved, the calibration efficiency is improved, and the applicability is wide.

This invention proposes a method for decoupling and controlling the pointing of sub-beams in a laser array, belonging to the field of beam combining technology. The method includes: acquiring an initial spot image on the target surface as an initial reference image; acquiring the offset of each sub-spot relative to the target position based on the initial reference image; sequentially applying perturbations to each beam pointing correction device according to a preset order and acquiring the current perturbed spot image; performing pixel-by-pixel difference operations between the current perturbed spot image and the initial reference image to obtain a differential energy map and perform energy detection, thereby determining the sub-spot corresponding to the current beam pointing correction device; applying perturbations to each beam pointing correction device to establish the correspondence between all sub-spots and beam pointing correction devices; and calculating the control voltage to correct the offset of each sub-spot using a control model to achieve one-step correction of large pointing errors in each sub-beam. This invention is applicable to the rapid correction of large pointing errors in laser arrays.

The invention discloses an array joint likelihood detection method and system for air-ground unmanned aerial vehicle optical communication, and aims to solve the problem of communication reliability caused by atmospheric turbulence and pointing errors in a complex electromagnetic environment. The method comprises the steps that a multi-factor coupling channel model including turbulence attenuation and pointing error attenuation is constructed, a double-Gamma statistical model is adopted for turbulence attenuation, and pointing errors are quantized through a zero-bias Rayleigh jitter model; estimating emission signal amplitude, equivalent gain of each channel and noise statistical characteristics by using the training symbols; an M * N detector array is adopted to obtain multichannel signals, joint likelihood detection (JLD) is executed, and the bit error rate is reduced through multichannel fusion and adaptive threshold judgment. The system comprises a transmitting end, an air-ground optical transmission link and a receiving end, wherein the receiving end is integrated with a large-field-of-view array and a signal processing module. According to the invention, cooperative compensation of turbulence and pointing errors is realized, link stability and anti-interference capability are improved, and the method is suitable for unmanned aerial vehicle communication scenes such as urban low altitude and mountainous open space.

The invention provides a high-precision inter-satellite pointing control method fusing laser interference measurement, and relates to the field of spacecraft control. The method comprises the following steps: firstly, carrying out validity judgment and processing on an attitude error value provided by the measurement of the laser interferometer in the period, carrying out attitude angular velocity differential calculation, and when the attitude error value provided by the measurement of the laser interferometer in the period is valid, carrying out reference error calculation in combination with an attitude error value provided by orbit extrapolation and on-satellite attitude determination; then, according to attitude error value validity provided by measurement of the laser interferometer in the current period and the last period, on the basis of a reference introduction / direct introduction selection mark set on the ground, determining to implement reference introduction calculation or direct introduction calculation, calculating an attitude control quantity and an angular velocity control quantity, and finally, according to the attitude control quantity and the angular velocity control quantity, calculating the attitude control quantity and the angular velocity control quantity. An attitude control moment is calculated by using a control law and is implemented by an execution mechanism. According to the invention, high-precision pointing error measurement of the laser interferometer is introduced, so that high-precision inter-satellite pointing control of satellites is realized.

The invention discloses a laser pointing error optimization method and system based on a multi-channel coaxial optical path, and the method comprises the steps: obtaining outdoor maintenance imaging data of electrical equipment of a transformer substation and a corresponding maintenance imaging distance, carrying out the optical parameter disassembly processing, constructing a plurality of optical path channels, and analyzing a corresponding optical path main axis; and performing independent parameter iteration processing on each light path channel to calculate the minimum aberration coefficient of each light path channel, further judging the light path pointing difference between the channels, and calculating the laser pointing error of each light path channel deviating from the main axis of the light path according to the light path pointing difference. And deviation aberration distribution of the corresponding light path channels in the deviation light path direction is analyzed to construct a laser direction error correction matrix, and laser direction error compensation optimization processing is performed on the corresponding light path channels to obtain laser direction error optimization data of the multi-channel coaxial light path. The method and the device have the effect of improving the laser pointing accuracy of outdoor discharge detection of the substation equipment.

The invention discloses a laser communication terminal pointing error real-time compensation method based on orbit space-time characteristics and a satellite-borne laser communication terminal. According to the method, the orbit operation periodicity of a satellite is utilized, and a multi-orbit period and angle partition iterative learning and compensation mode is adopted; the method is used for systematically correcting the installation angle deviation caused by slow change factors such as thermal deformation of an installation surface, and specifically comprises the following steps: in a link establishment process of a first track period, when a terminal runs to a certain preset angle partition, a system synchronously records and calculates a pointing error of the interval; starting from a second track period, when the terminal runs to the learned angle partition again, the system automatically injects the installation angle deviation of the partition learned and stored in the previous track, and the installation angle deviation serves as a feed-forward compensation amount to pre-correct the current direction; and all common working angles of the terminal can be covered step by step through operation of a plurality of continuous track periods. The method ensures that the pointing precision of the terminal can be dynamically maintained and continuously optimized in a long-term on-orbit task.

The invention provides a servo turntable pointing error correction method which can be applied to the technical field of photoelectric measuring instrument calibration. The method comprises the steps that three-dimensional coordinates of a servo turntable are obtained through an RTK reference positioning base station, the servo turntable is adjusted to be aligned with a calibration target, and the azimuth angle of the aligned servo turntable serves as a geodetic zero point; controlling the unmanned aerial vehicle to hover at a plurality of measurement points in the target correction airspace, and converting the real-time three-dimensional coordinates of the RTK reference positioning base station relative to the unmanned aerial vehicle into a theoretical azimuth angle and theoretical pitch relative to the servo turntable; adjusting the unmanned aerial vehicle to the central position of a camera view field by adjusting the direction of the servo turntable to obtain a real azimuth angle and a real pitch angle of the servo turntable; and fitting the pointing error model by using the pointing error, calculating to obtain a pointing correction coefficient of the servo turntable, and correcting the pointing error of the servo turntable by using the pointing correction coefficient.

The invention provides a free space optical communication adaptive beam alignment method in a low-altitude dynamic environment, which comprises the following steps: considering the influence of atmospheric loss, atmospheric turbulence, pointing error and arrival angle fluctuation on a link in the low-altitude environment, constructing a channel model of a U2U free space optical communication system, and deducing the outage probability of system communication; constructing an adaptive beam alignment optimization problem model for minimizing the free space optical communication link outage probability in the low-altitude dynamic environment; an adaptive beam alignment optimization problem model is solved based on an adaptive exploration driven depth deterministic strategy gradient algorithm AED-DDPG, and algorithm performance is improved through joint optimization of transmitting power, a divergence angle and a view angle; and a U2U adaptive alignment scheme in a low-altitude dynamic environment is obtained. According to the method, the problem of minimizing the outage probability of a communication link in a complex dynamic scene is solved, and the beam alignment performance is improved, so that the system communication performance is improved.

A method for calibrating the target pointing error of a multimode composite tracking and aiming system includes: (1) setting up an autocollimator in front of the multimode optical system and the field of view of the visible light camera, calibrating the multimode optical system and marking the zero point of the visible light camera; (2) placing a target at the maximum measurement distance of the multimode optical system and marking the position of the camera zero point in the target target; then rotating the azimuth and pitch axes of the high-precision turntable to zero, reading the imaging position of the laser emission point, and recording the system deviation of the target pointing; (3) controlling the azimuth and pitch axes of the high-precision turntable to swing to different angles, and measuring the deviation value between the tracking point of the visible light camera and the imaging position of the target laser illumination point; (4) substituting the measured value into the error calculation formula including the mirror installation deviation to form a multivariate equation system, solving for the mirror installation error of the multimode composite tracking and aiming system, and then combining the swing angles of the azimuth and pitch axes of the high-precision turntable to calculate the corresponding deviation value. The method of this invention can accurately calibrate the target pointing error of the multimode composite tracking and aiming system.

The present application relates to a kind of laser array pointing error correction system based on light intensity gradient potential well, belong to laser technology field, the method includes setting adaptive fiber collimator array, extended target, target area optical imaging lens, beam splitter, light intensity gradient potential well modulating piece, photoelectric detector, control platform, high voltage amplifier and imaging camera connected to beam splitter.Laser array is emitted via adaptive fiber collimator array, is transmitted to the light spot pattern formed on extended target, the light spot pattern is imaged by target area optical imaging lens of emission end, after imaging beam passes through light intensity gradient potential well modulating piece, image on the photosensitive surface of photoelectric detector, the photoelectric conversion signal of photoelectric detector is transmitted to control platform, control voltage signal is generated after being calculated by optimization control algorithm, act on adaptive fiber collimator array, realize the pointing error closed-loop correction of emission beam, finally realize beam synthesis in the specific position of extended target.

The invention discloses a CBCT craniojaw median sagittal plane automatic fitting method based on deep learning, and the method comprises the following steps: data preprocessing: obtaining CBCT image data, carrying out the format conversion, resampling and data enhancement processing of an original CBCT image, and obtaining standardized training data, verification data and test data; the method has the advantages that a two-stage network structure combining 3D U-Net and LSTM is adopted, high-precision automatic positioning of key anatomical points is achieved, the average positioning error is only 0.9671 mm, the errors of all the points are smaller than 1.2 mm, the detection success rate under the threshold value of 2 mm reaches 98.03%, the precision reaches the labeling level of high-age doctors, and the accuracy of median sagittal plane fitting is guaranteed; the TLS algorithm is introduced to carry out median sagittal plane fitting, discrete points or abnormal points can be automatically eliminated, the method has high robustness for outliers, excellent performance can be kept in complex cases such as symmetric cases and jaw deflection cases, the angle average errors of a symmetric group and a jaw deflection group are 0.4717 degrees and 0.47599 degrees respectively, and the method is superior to a traditional fitting method.

The application discloses a kind of mark point error identification and elimination method, device, equipment and storage medium, method is by obtaining the observation ray set of target mark point under multiple camera visual angle, establish local three-dimensional coordinate system with target mark point as origin, and according to the included angle distribution of observation ray relative to the main shaft of local three-dimensional coordinate system, observation ray set is divided into at least two direction regions;According to the ray number distribution in each direction region divided out, the overall observation quality of target mark point is judged, when overall observation quality satisfies preset condition, the comprehensive score of each observation ray is carried out, and the observation ray that comprehensive quality score does not satisfy preset screening condition is eliminated, and the ray set after screening is obtained;According to ray set, the three-dimensional coordinates of target mark point are calculated by preset space front intersection algorithm;It can realize the deep evaluation of mark point overall observation geometric quality, and the precision, stability and algorithm robustness of mark point three-dimensional coordinate reconstruction are improved.

The application discloses a Q / V frequency band low-orbit three-axis antenna pointing mark calibration method based on an MPA algorithm and belongs to the field of satellite communication antenna servo control. The method comprises the following steps: defining to-be-optimized parameters representing a plurality of error sources of a three-axis antenna; defining an error index function for evaluating pointing deviation; acquiring tracking data of a multi-orbit satellite as a training data set; establishing a pointing error correction model with a measurement angle as input and the defined parameters for correction; iteratively optimizing parameters in the model by using a marine predator algorithm (MPA) to minimize the error index function and obtain an optimal parameter set; and configuring the optimal parameter set to a servo control system for real-time tracking error correction. The application utilizes on-orbit data, does not need additional equipment, and can realize fast calibration only by using 1-2 orbit data, significantly improves pointing precision and high-elevation tracking stability, and is suitable for large-scale and rapid deployment.

The invention discloses a space laser communication method and system based on a cascade liquid crystal polarization grating device, and relates to the technical field of space laser communication. A cascade liquid crystal polarization grating module is used for executing discrete deflection based on an electric control liquid crystal phase to output a coarse pointing light beam, and a fine tracking deflection module is used for executing continuous angle compensation. The control module generates a state code based on the coarse tracking error, looks up a table and outputs a grating driving signal; and a precise tracking deflection module is driven based on the precise tracking error, and when the continuous compensation angle reaches the upper limit or the pointing error exceeds the limit, a state code is updated based on the continuous compensation angle or the pointing error, the grating is driven to discretely deflect, and the precise tracking deflection module is reset to zero. According to the method, large-range, high-precision and stable pointing control is realized through cooperation of non-mechanical discrete coarse pointing and continuous fine tracking in combination with table look-up driving, saturated unloading and pointing monitoring mechanisms. And further, multi-channel waveform pre-emphasis driving and Gray code coding are combined, so that transient disturbance of state switching is effectively inhibited.