Method and device for reconstructing interrupted link in satellite-ground laser communication based on downward spot off-target amount

Abstract

The present invention provides a method and device for reconstructing the disconnection of satellite-ground laser communication based on the off-target amount of the downlink light spot. When the downlink signal light spot appears in the coarse tracking field of view, the ground station is controlled to start the coarse tracking closed-loop process; the off-target amount of the downlink signal light spot is determined, the servo pointing is corrected based on the off-target amount, and the off-target amount is recorded; when the downlink signal light spot in the coarse tracking field of view disappears, the coarse tracking closed-loop is turned off; based on the recorded off-target amount, the predicted correction amount of the servo pointing at each moment after the disappearance of the downlink signal light spot is predicted; based on the predicted correction amount at each moment, the servo pointing is corrected to obtain the predicted corrected pointing of the servo at each moment; when the downlink signal light spot appears in the coarse tracking field of view, the predicted corrected pointing corresponding to the moment when the downlink signal light spot appears is searched; based on the corresponding predicted corrected pointing, the coarse tracking closed-loop is started to reconstruct the satellite-ground laser communication link, realizing fast link reconstruction and improving the efficiency of re-linking.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and particularly to a method and device for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink spot. Background Art

[0002] During the process of satellite-ground laser communication, situations that may cause link interruption may occur, such as over-the-top blind area avoidance, transit avoidance, cloud occlusion, etc. The above interruption events require the ground station to quickly re-capture the satellite signal after the link is interrupted to restore the communication link.

[0003] In the prior art, after the above link is interrupted, the ground station needs to re-align with the satellite. However, due to the deviation of the trajectory prediction, the satellite may have deviated from the coverage range of the uplink beacon light of the ground station, which increases the difficulty of re-establishing the communication link. In addition, after the spot is lost, the existing coarse tracking closed-loop system cannot effectively predict and correct the servo pointing, resulting in the inability to quickly re-capture the downlink signal spot and quickly reconstruct the link. Summary of the Invention

[0004] The present invention provides a method and device for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink spot, so as to solve the technical problem that the link cannot be quickly reconstructed after the satellite-ground laser communication link is broken in the prior art.

[0005] On the one hand, the present invention provides a method for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink spot, including:

[0006] When a downlink signal spot appears in the coarse tracking field of view, controlling the ground station to start the coarse tracking closed-loop process to establish a satellite-ground laser communication link;

[0007] Determining the off-target amount of the downlink signal spot, correcting the servo pointing based on the off-target amount, and recording the off-target amount;

[0008] When the downlink signal spot in the coarse tracking field of view disappears, closing the coarse tracking closed-loop to disconnect the satellite-ground laser communication link;

[0009] Based on the recorded off-target amount, predicting the predicted correction amount of the servo pointing at each moment after the downlink signal spot disappears;

[0010] Based on the predicted correction amount at each moment, correcting the servo pointing to obtain the predicted correction pointing of the servo at each moment;

[0011] When a downlink signal spot appears in the coarse tracking field of view, searching for the predicted correction pointing corresponding to the moment when the downlink signal spot appears;

[0012] Based on the corresponding predicted correction direction, start the coarse tracking closed loop to reconstruct the space-to-ground laser communication link.

[0013] According to a space-to-ground laser communication link break reconstruction method based on the downward spot offset amount provided by the present invention, predicting the predicted correction amount of the servo pointing at each moment after the disappearance of the downward signal spot based on the recorded spot offset amount includes:

[0014] Obtain a preset initial parameter vector and construct a non-linear variation function of the initial parameter vector in the time dimension;

[0015] Based on the non-linear variation function, determine the partial derivative of the initial parameter vector;

[0016] Based on the partial derivative of the initial parameter vector, construct a Jacobian matrix;

[0017] Based on the Jacobian matrix, iteratively update the initial parameter vector to obtain a parameter update result;

[0018] Judge whether the parameter update result meets a preset iteration stop condition;

[0019] If so, stop iteratively updating the initial parameter vector and use the parameter update result after stopping the iterative update to fit the non-linear variation function;

[0020] Based on the fitted non-linear variation function, obtain the predicted correction amount of the servo pointing at each moment after the disappearance of the downward signal spot.

[0021] According to a space-to-ground laser communication link break reconstruction method based on the downward spot offset amount provided by the present invention, the non-linear variation function is shown in the following formula:

[0022] ; where is time, is the initial parameter vector, with the unit of degree;

[0023] The Jacobian matrix is shown in the following formula:

[0024] ; where is the element in the i-th row and j-th column of the Jacobian matrix J; , n is the number of samples, m is the number of parameters; i is the index of the number of samples, i belongs to 1 to n; j is the index of the number of parameters, j is 1 to m.

[0025] According to a space-to-ground laser communication link break reconstruction method based on the downward spot offset amount provided by the present invention, the iterative update of the initial parameter vector to obtain a parameter update result includes:

[0026] The Levenberg-Marquardt method is used to iteratively update the initial parameter vector to obtain the parameter update result.

[0027] According to a method for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink light spot provided by the present invention, the step of using the Levenberg-Marquardt method to iteratively update the initial parameter vector to obtain the parameter update result includes:

[0028] ; where k is the number of iterations; is the initial parameter vector for the k-th iteration; is the initial parameter vector for the (k + 1)-th iteration; is the update amount of the initial parameter vector in the k-th iteration;

[0029] where ; where is the adjustment factor; I is the identity matrix; is the residual vector;

[0030] where ; is the off-target amount of the light spot.

[0031] According to a method for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink light spot provided by the present invention, the step of using the parameter update result after stopping the iterative update to fit the non-linear variation function includes:

[0032] ; where is the off-target amount of the light spot at time t; is the parameter update result after stopping the iterative update.

[0033] According to a method for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink light spot provided by the present invention, the preset iterative stop condition includes:

[0034] The sum of the squares of the residuals of the residual vector converges; or

[0035] The off-target amount of the light spot is less than the preset convergence accuracy.

[0036] According to a method for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink light spot provided by the present invention, the step of correcting the servo pointing based on the off-target amount of the light spot includes:

[0037] Based on the off-target amount of the light spot, use PID to correct the servo pointing.

[0038] On the other hand, the present invention also provides a device for reconstructing a broken link in satellite-ground laser communication based on the off-target amount of a downlink light spot, including:

[0039] The coarse tracking module controls the ground station to start the coarse tracking closed-loop process to establish a space-to-ground laser communication link when a downlink signal light spot appears in the coarse tracking field of view;

[0040] The light spot offset amount module determines the light spot offset amount of the downlink signal light spot, corrects the servo pointing based on the light spot offset amount, and records the light spot offset amount;

[0041] The closing module closes the coarse tracking closed-loop to disconnect the space-to-ground laser communication link when the downlink signal light spot in the coarse tracking field of view disappears;

[0042] The prediction module predicts the predicted correction amount of the servo pointing at each moment after the downlink signal light spot disappears based on the recorded light spot offset amount;

[0043] The correction module corrects the servo pointing based on the predicted correction amount at each moment to obtain the predicted correction pointing of the servo at each moment;

[0044] The searching module searches for the predicted correction pointing corresponding to the moment when the downlink signal light spot appears when the downlink signal light spot appears in the coarse tracking field of view;

[0045] The reconstruction module starts the coarse tracking closed-loop based on the corresponding predicted correction pointing to reconstruct the space-to-ground laser communication link.

[0046] On the other hand, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements any one of the above space-to-ground laser communication disconnection and reconstruction methods based on the downlink light spot offset amount.

[0047] The space-to-ground laser communication disconnection and reconstruction method and device based on the downlink light spot offset amount provided by the present invention, when the downlink signal light spot in the coarse tracking field of view disappears, closes the coarse tracking closed-loop to disconnect the space-to-ground laser communication link; predicts the predicted correction amount of the servo pointing at each moment after the downlink signal light spot disappears based on the recorded light spot offset amount; corrects the servo pointing based on the predicted correction amount at each moment to obtain the predicted correction pointing of the servo at each moment; when the downlink signal light spot appears in the coarse tracking field of view, searches for the predicted correction pointing corresponding to the moment when the downlink signal light spot appears; and starts the coarse tracking closed-loop based on the corresponding predicted correction pointing to reconstruct the space-to-ground laser communication link, realizing that when facing situations such as over-the-top blind area avoidance, transit avoidance, and cloud occlusion, by predicting and correcting the servo pointing, the communication link can be quickly and accurately re-established, improving the stability and reliability of the communication link. Description of the Drawings

[0048] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0049] Figure 1 is a schematic flowchart of a satellite-ground laser communication disconnection reconstruction method based on the downlink spot off-target amount provided by an embodiment of the present invention;

[0050] Figure 2 is a schematic architecture diagram of the ground end coarse tracking of satellite-ground laser communication provided by an embodiment of the present invention;

[0051] Figure 3 is a schematic structural diagram of a satellite-ground laser communication disconnection reconstruction device based on the downlink spot off-target amount provided by an embodiment of the present invention;

[0052] Figure 4 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention. Detailed implementation manners

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0054] In satellite communication, the downlink signal spot refers to the intersection area of the concentrated radio beam emitted by the satellite to the ground and the Earth's surface. The spot off-target amount refers to the deviation amount of the spot relative to the predetermined target position. In satellite laser communication, the spot off-target amount is a key technical index, which measures the positioning accuracy of the spot at the receiving end. Specifically, the spot off-target amount refers to the deviation distance of the spot relative to the center position of the receiver. This deviation distance can be calculated by the image processing module and used for the control system to make adjustments to ensure that the spot can accurately align with the center of the receiver. In the actual tracking process, the system will use the spot off-target amount to dynamically adjust the position of the receiver to keep the spot at the best position in the center of the receiver, thereby achieving efficient signal reception and processing.

[0055] Figure 1 is a schematic flowchart of a satellite-ground laser communication disconnection reconstruction method based on the downlink spot off-target amount provided by an embodiment of the present invention.

[0056] See Figure 1, the method for reconstructing the disconnection of satellite - to - ground laser communication based on the off - target amount of the downlink light spot may include the following steps 101 to 107.

[0057] 101. When the downlink signal light spot appears in the coarse tracking field of view, control the ground station to start the coarse tracking closed - loop process to establish a satellite - to - ground laser communication link.

[0058] The tracking of the satellite generally can be divided into coarse tracking and fine tracking. For those skilled in the art, both coarse tracking and fine tracking are clear concepts. Coarse tracking and fine tracking can also be replaced by the first preset tracking method and the second preset tracking method respectively, and the tracking accuracy of the second preset tracking method is greater than that of the first preset tracking method.

[0059] 102. Determine the off - target amount of the downlink signal light spot, correct the servo pointing based on the off - target amount, and record the off - target amount.

[0060] This step generally may include:

[0061] Image acquisition: Real - time acquire the images within the coarse tracking field of view through the coarse tracking camera. These images contain the position information of the downlink signal light spot.

[0062] Image pre - processing: Pre - process the acquired images, including operations such as denoising, contrast enhancement, and edge detection, to improve the accuracy of light spot position detection.

[0063] Light spot position extraction: Use image - processing algorithms (such as centroid algorithm, template matching, or deep - learning algorithm) to extract the centroid position coordinates of the downlink signal light spot from the pre - processed images. The centroid position is usually regarded as the center position of the light spot.

[0064] Calculate the off - target amount: Compare the extracted centroid position coordinates of the light spot with the preset target position coordinates to calculate the off - target amount of the light spot.

[0065] The off - target amount of the light spot usually includes two components. For example:

[0066] Azimuth off - target amount: Represents the deviation of the light spot in the horizontal direction; Elevation off - target amount: Represents the deviation of the light spot in the vertical direction.

[0067] 103. When the downlink signal light spot in the coarse tracking field of view disappears, close the coarse tracking closed - loop to disconnect the satellite - to - ground laser communication link.

[0068] 104. Based on the recorded off - target amount of the light spot, predict the predicted correction amount of the servo pointing at each moment after the disappearance of the downlink signal light spot.

[0069] Specifically, based on the recorded off - target amount of the light spot, predicting the predicted correction amount of the servo pointing at each moment after the disappearance of the downlink signal light spot may include:

[0070] Obtain a preset initial parameter vector and construct a non - linear variation function of the initial parameter vector in the time dimension;

[0071] Based on the non - linear variation function, determine the partial derivative of the initial parameter vector;

[0072] Based on the partial derivative of the initial parameter vector, construct a Jacobian matrix;

[0073] Based on the Jacobian matrix, perform iterative update on the initial parameter vector to obtain a parameter update result;

[0074] Judge whether the parameter update result meets the preset iterative stop condition;

[0075] If so, stop the iterative update of the initial parameter vector and use the parameter update result after stopping the iterative update to fit the non - linear variation function;

[0076] Based on the fitted non - linear variation function, obtain the predicted correction amount of the servo pointing at each moment after the disappearance of the downlink signal spot.

[0077] If not, continue to perform the iterative update on the initial parameter vector.

[0078] In this step, through the construction of the non - linear variation function and the Jacobian matrix, and the iterative update of the parameter vector, the correction amount of the servo pointing can be predicted more accurately, thereby improving the accuracy of the broken - link reconstruction.

[0079] 105. Based on the predicted correction amount at each moment, correct the servo pointing to obtain the predicted corrected pointing of the servo at each moment.

[0080] 106. When a downlink signal spot appears in the coarse - tracking field of view, find the predicted corrected pointing corresponding to the moment when the downlink signal spot appears.

[0081] In this step, when a downlink signal spot appears in the coarse - tracking field of view, it means when the downlink signal spot appears again in the coarse - tracking field of view. The previous steps have predicted the predicted corrected pointing at each moment after the link break. Therefore, when the downlink signal spot appears again, the predicted corrected pointing at the moment when the downlink signal spot appears again can be determined.

[0082] 107. Based on the corresponding predicted corrected pointing, turn on the coarse - tracking closed - loop to reconstruct the satellite - to - ground laser communication link.

[0083] In this embodiment, when the downlink signal spot in the coarse tracking field of view disappears, the coarse tracking closed loop is turned off to disconnect the satellite-ground laser communication link; based on the recorded spot off-target amount, the predicted correction amount of the servo pointing at each moment after the disappearance of the downlink signal spot is predicted; based on the predicted correction amount at each moment, the servo pointing is corrected to obtain the predicted corrected pointing of the servo at each moment; when the downlink signal spot appears in the coarse tracking field of view, the predicted corrected pointing corresponding to the moment when the downlink signal spot appears is searched; based on the corresponding predicted corrected pointing, the coarse tracking closed loop is turned on to reconstruct the satellite-ground laser communication link, achieving the re-rapid and accurate establishment of the communication link by predicting and correcting the servo pointing in the face of situations such as over-the-top blind area avoidance, transit avoidance, and cloud occlusion, improving the stability and reliability of the communication link.

[0084] In one embodiment of this specification, the non-linear variation function is shown as the following formula (1):

[0085] (1); where is time, is the initial parameter vector, with the unit of degree.

[0086] The Jacobian matrix is shown as the following formula (2):

[0087] (2); where is the element in the i-th row and j-th column of the Jacobian matrix J; , n is the number of samples, m is the number of parameters; i is the index of the number of samples, i belongs to 1 to n; j is the index of the number of parameters, j is 1 to m.

[0088] In this embodiment, the relationship between the spot off-target amount and time, as well as the influence of the parameter vector on the model, is quantified, providing a mathematical basis for the iterative update of the parameter vector, which is beneficial to improving the accuracy of prediction.

[0089] In one embodiment of this specification, the initial parameter vector is iteratively updated to obtain the parameter update result, including:

[0090] The Levenberg-Marquardt method is used to iteratively update the initial parameter vector to obtain the parameter update result.

[0091] In this embodiment, the efficiency and stability of the Levenberg-Marquardt algorithm are utilized to optimize the update process of the parameter vector to obtain a more accurate predicted correction amount.

[0092] In one embodiment of this specification, the step of using the Levenberg-Marquardt method to iteratively update the initial parameter vector to obtain the parameter update result includes:

[0093] (3); where k in formula (3) is the number of iterations; is the initial parameter vector for the k-th iteration; is the initial parameter vector for the (k + 1)-th iteration; is the update amount of the initial parameter vector in the k-th iteration. It can be expressed by the following formula (4).

[0094] (4); where is the adjustment factor; I is the identity matrix; is the residual vector. It can be expressed by the following formula (5).

[0095] (5); where is the spot miss amount.

[0096] In this embodiment, the update amount of the parameter vector in each iteration is accurately calculated, thereby gradually approaching the optimal parameter vector. The spot miss amount can include the azimuth miss amount and the pitch miss amount of the servo. That is, the above formulas can ultimately predict the azimuth miss amount and the pitch miss amount of the servo.

[0097] In an embodiment of this specification, the parameter update result after stopping iterative update is used to fit a non-linear variation function, including the following formula (6):

[0098] (6); where is the spot miss amount at time t; is the parameter update result after stopping iterative update.

[0099] In this embodiment, it is possible to accurately predict the spot miss amount at a specific moment according to the optimal parameter vector, providing a basis for correcting the servo pointing.

[0100] In an embodiment of this specification, preset iterative stop conditions are included:

[0101] The sum of the squared residuals of the residual vector converges; or

[0102] The spot miss amount is less than the preset convergence accuracy.

[0103] In this embodiment, through the above preset iterative stop conditions, over-iteration can be avoided, computational resources can be saved, and at the same time, the accuracy of the predicted correction amount can be ensured. In addition, the preset maximum number of iterations can also be used as the preset iterative stop condition.

[0104] In an embodiment of this specification, correcting the servo pointing based on the spot miss amount may include:

[0105] Based on the spot off-target amount, proportional-integral-derivative (PID) is used to correct the servo pointing.

[0106] In this embodiment, by utilizing the stability and robustness of PID control, the servo pointing is corrected in real time to quickly and accurately re-establish the communication link.

[0107] In some other embodiments of the present invention, before determining the spot off-target amount of the downlink signal spot, the following steps may further be included:

[0108] Spot detection and preprocessing: The images within the coarse tracking field of view are detected in real time to identify the position information of the downlink signal spot, and the detected spot images are preprocessed, including denoising, enhancing contrast, and edge detection, to improve the accuracy of spot position detection;

[0109] Spot position extraction: Through an image processing algorithm, the centroid position coordinates of the downlink signal spot are extracted from the preprocessed image as the reference point of the spot position;

[0110] Spot off-target amount calculation: According to the extracted centroid position coordinates of the spot and the preset target position coordinates, the spot off-target amount is calculated, and the spot off-target amount includes the azimuth off-target amount and the pitch off-target amount, respectively representing the deviation amounts of the spot in the horizontal and vertical directions.

[0111] In some other embodiments of the present invention, when correcting the servo pointing based on the spot off-target amount, the following steps may further be included:

[0112] PID parameter optimization: According to the historical spot off-target amount data and the servo correction response characteristics, the parameters of the proportional-integral-derivative (PID) controller are dynamically adjusted to optimize the performance of the servo pointing correction and reduce the overshoot and steady-state error during the correction process;

[0113] Multi-dimensional correction strategy: Combining the azimuth component and the pitch component of the spot off-target amount, the azimuth axis and the pitch axis of the servo system are independently corrected respectively to achieve precise adjustment of the spot position;

[0114] Correction effect evaluation and feedback: After each correction, the position of the downlink signal spot is detected again, the spot off-target amount after correction is calculated, and compared with the spot off-target amount before correction to evaluate the correction effect; if the spot off-target amount after correction does not meet the preset accuracy requirements, the PID parameters or the correction strategy are adjusted according to the correction effect, and the correction is performed again until the spot off-target amount meets the requirements for establishing the communication link.

[0115] In some other embodiments of the present invention, before determining the spot miss amount of the downlink signal spot, the following steps may further be included:

[0116] Spot detection by multi-source data fusion:

[0117] Obtain spot image data from an image sensor within the coarse tracking field of view, and combine satellite orbit prediction data, meteorological data, and historical communication link data to detect the downlink signal spot through a multi-source data fusion algorithm;

[0118] The multi-source data fusion algorithm includes, but is not limited to, Bayesian fusion, Kalman filter fusion, or neural network fusion to improve the accuracy and reliability of spot detection.

[0119] Spot feature extraction and enhancement:

[0120] Extract features from the detected spot image, and the extracted features include the centroid position of the spot, light intensity distribution, spot shape, and edge features;

[0121] Based on the extracted features, perform enhancement processing on the spot image, including spot contrast enhancement, background noise suppression, and spot shape correction to improve the accuracy of spot miss amount calculation.

[0122] Dynamic spot miss amount calculation model:

[0123] According to the extracted spot features and preset target position coordinates, establish a dynamic spot miss amount calculation model, which can adapt to factors such as spot shape changes, light intensity fluctuations, and atmospheric disturbances in real time;

[0124] The dynamic spot miss amount calculation model is trained based on machine learning algorithms, and the training data includes historical spot image data, spot miss amount data, and environmental parameter data to improve the generalization ability and prediction accuracy of the model, thereby calculating the spot miss amount.

[0125] Multi-dimensional decomposition of spot miss amount:

[0126] Decompose the calculated spot miss amount into azimuth miss amount, pitch miss amount, and spot shape deviation amount, where the spot shape deviation amount is used to evaluate the ellipticity and symmetry of the spot;

[0127] According to the multi-dimensional decomposition results, perform weighted processing on the spot miss amount to highlight the main deviation direction (the larger the deviation, the relatively larger the weight), and optimize the subsequent servo pointing correction strategy.

[0128] Figure 2 It is a schematic diagram of the architecture of the ground end coarse tracking of satellite-ground laser communication provided by the embodiments of the present invention. Combined with Figure 2, an introduction to the coarse tracking of the present invention is provided. The transmitting module at the ground end can transmit an uplink light beam to the satellite. The coarse tracking optical branch and the coarse tracking camera can also be regarded as a unified post-optical path module.

[0129] Step 1: The ground end receives the laser signal (i.e., the downlink light beam) sent by the satellite to the ground end through the optical antenna, and guides the downlink light beam to the receiving primary mirror.

[0130] Step 2: The receiving primary mirror focuses the received downlink light beam into the subsequent coarse tracking optical branch.

[0131] Step 3: The coarse tracking optical branch can separate a part of the downlink light beam for coarse tracking and branch it to the coarse tracking camera.

[0132] Step 4: The coarse tracking camera is used to capture the images of the downlink light beam. These images contain the position information of the light spot. The deviation of the light beam is determined by detecting the position of the light spot. Then, the captured downlink light beam capture images are sent to the image processing server.

[0133] Step 5: The image processing server receives the downlink light beam capture images from the coarse tracking camera, processes and analyzes them to determine the precise position and deviation of the light beam. Based on this data, the image processing server generates corresponding control signals to indicate how the servo system should adjust the direction of the optical antenna, that is, perform servo correction.

[0134] Step 6: The servo calculates the required servo correction amount according to the results analyzed by the image processing server, and then adjusts the angle of the optical antenna or the receiving primary mirror through the servo system to reduce the deviation of the light beam and achieve the coarse tracking of the downlink light beam.

[0135] The above entire process is a closed-loop control system. Through continuous detection, processing, and correction, it ensures that the downlink light beam can be stably received by the ground station. The purpose of coarse tracking is to quickly capture and roughly align with the satellite's downlink light beam, providing a basis for subsequent fine tracking.

[0136] The coarse tracking closed-loop is the preliminary alignment process for the ground station or the satellite to re-capture the signal of the other party after the laser communication link is interrupted. When the downlink signal light spot appears in the coarse tracking field of view of the ground station, the ground station starts the coarse tracking closed-loop process. The coarse tracking closed-loop can use the PID (Proportional-Integral-Derivative) algorithm to correct the servo pointing to reduce the off-target amount of the light spot (i.e., the deviation between the light spot and the expected target). This process records the off-target amount of the light spot, providing data support for the prediction of subsequent servo correction amounts. The purpose of the coarse tracking closed-loop is to quickly align the laser beam to a roughly correct direction so as to be able to capture the signal of the other party.

[0137] The fine tracking closed-loop is a process that further improves the alignment accuracy of the laser beam after the coarse tracking closed-loop. When the coarse tracking closed-loop successfully captures the signal, the fine tracking closed-loop starts to work to achieve a higher-precision alignment. The fine tracking closed-loop may use more advanced control algorithms, such as Kalman filtering, to compensate for errors caused by atmospheric disturbances, mechanical vibrations, etc. This process ensures that the laser beam can be stably aligned with the target, thereby establishing a high-quality laser communication link. The purpose of the fine tracking closed-loop is to achieve high-precision alignment and ensure the stability of communication and the accuracy of data transmission. In the method for reconstructing the broken link of satellite-ground laser communication, the coarse tracking closed-loop and the fine tracking closed-loop work together to ensure that the communication link can be quickly and accurately re-established after the link is interrupted. The coarse tracking closed-loop provides a quick initial alignment, and the fine tracking closed-loop provides a more refined adjustment on this basis to achieve stable communication.

[0138] Based on the same general inventive concept, the present invention also protects a satellite-ground laser communication broken link reconstruction device based on the off-target amount of the downlink spot, as Figure 3 shown Figure 3 is a schematic structural diagram of the satellite-ground laser communication broken link reconstruction device based on the off-target amount of the downlink spot provided by an embodiment of the present invention. The satellite-ground laser communication broken link reconstruction device based on the off-target amount of the downlink spot provided by the present invention will be described below. The satellite-ground laser communication broken link reconstruction device based on the off-target amount of the downlink spot described below can be correspondingly referred to the satellite-ground laser communication broken link reconstruction method described above.

[0139] The satellite-ground laser communication broken link reconstruction device based on the off-target amount of the downlink spot includes a coarse tracking module 301, a spot off-target amount module 302, a closing module 303, a prediction module 304, a correction module 305, a search module 306, and a reconstruction module 307.

[0140] When a downlink signal spot appears in the coarse tracking field of view, the coarse tracking module 301 controls the ground station to start the coarse tracking closed-loop process to establish a satellite-ground laser communication link;

[0141] The spot off-target amount module 302 determines the off-target amount of the downlink signal spot, corrects the servo pointing based on the off-target amount, and records the off-target amount;

[0142] When the downlink signal spot in the coarse tracking field of view disappears, the closing module 303 closes the coarse tracking closed-loop to disconnect the satellite-ground laser communication link;

[0143] Based on the recorded off-target amount of the spot, the prediction module 304 predicts the predicted correction amount of the servo pointing at each moment after the disappearance of the downlink signal spot;

[0144] Based on the predicted correction amount at each moment, the correction module 305 corrects the servo pointing to obtain the predicted correction pointing of the servo at each moment;

[0145] When a downlink signal light spot appears in the coarse tracking field of view, the search module 306 searches for the predicted correction pointing corresponding to the moment when the downlink signal light spot appears.

[0146] Based on the corresponding predicted correction pointing, the reconstruction module 307 enables the coarse tracking closed loop to reconstruct the satellite-ground laser communication link.

[0147] Figure 4 It is a schematic structural diagram of the electronic device provided by the embodiment of the present invention.

[0148] As Figure 4 shown, the electronic device may include: a processor 410, a communications interface 420, a memory 430, and a communication bus 440. Among them, the processor 410, the communications interface 420, and the memory 430 complete communication with each other through the communication bus 440. The processor 410 can call the logical instructions in the memory 430 to execute the satellite-ground laser communication disconnection reconstruction method based on the downlink light spot offset amount.

[0149] In addition, when the logical instructions in the above-mentioned memory 430 are implemented in the form of software function units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0150] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the satellite-ground laser communication disconnection reconstruction method provided by the above-mentioned various methods.

[0151] On the other hand, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the method for reconstructing the disconnection of satellite-ground laser communication based on the downward spot miss amount provided by the above-mentioned various methods.

[0152] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0153] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reconstructing the disconnection of satellite-ground laser communication based on the off-target amount of the downlink light spot, characterized in that, Including: When a downward signal light spot appears in the coarse tracking field of view, control the ground station to start the coarse tracking closed-loop process to establish a space-ground laser communication link; Determine the light spot miss distance of the downward signal light spot, correct the servo pointing based on the light spot miss distance, and record the light spot miss distance; When the downward signal light spot in the coarse tracking field of view disappears, close the coarse tracking closed-loop to disconnect the space-ground laser communication link; Based on the recorded light spot miss distance, predict the predicted correction amount of the servo pointing at each moment after the disappearance of the downward signal light spot; Based on the predicted correction amount at each moment, correct the servo pointing to obtain the predicted corrected pointing of the servo at each moment; When a downward signal light spot appears in the coarse tracking field of view, find the predicted corrected pointing corresponding to the moment when the downward signal light spot appears; Based on the corresponding predicted corrected pointing, start the coarse tracking closed-loop to reconstruct the space-ground laser communication link; Among them, the predicting the predicted correction amount of the servo pointing at each moment after the disappearance of the downward signal light spot based on the recorded light spot miss distance includes: Obtain a preset initial parameter vector and construct a non-linear variation function of the initial parameter vector in the time dimension; Based on the non-linear variation function, determine the partial derivative of the initial parameter vector; Based on the partial derivative of the initial parameter vector, construct a Jacobian matrix; Based on the Jacobian matrix, iteratively update the initial parameter vector to obtain a parameter update result; Judge whether the parameter update result meets the preset iteration stop condition; If so, stop iteratively updating the initial parameter vector and use the parameter update result after stopping the iterative update to fit the non-linear variation function; Based on the fitted non-linear variation function, obtain the predicted correction amount of the servo pointing at each moment after the disappearance of the downward signal light spot; The non-linear variation function is shown in the following formula: ; wherein, is time, is the initial parameter vector, with the unit of degree; The Jacobian matrix is shown in the following formula: ; wherein, is the element in the i-th row and j-th column of the Jacobian matrix J; , n is the number of samples, m is the number of parameters; i is the index of the number of samples, i belongs to 1 to n; j is the index of the number of parameters, j is 1 to m; The iteratively updating the initial parameter vector to obtain a parameter update result includes: Use the Levenberg-Marquardt to iteratively update the initial parameter vector to obtain a parameter update result; The using the Levenberg-Marquardt to iteratively update the initial parameter vector to obtain a parameter update result includes: where k is the number of iterations; is the initial parameter vector for the k-th iteration; is the initial parameter vector for the (k + 1)-th iteration; is the update amount of the initial parameter vector in the k-th iteration; Among them, ; among them, is a regulation factor; I is an identity matrix; is a residual vector; Among them, ; is the spot miss amount; The using the parameter update result after stopping the iterative update to fit the non-linear variation function includes: ; wherein, is the spot miss amount at time t; is the parameter update result after stopping iterative update.

2. The method for reconstructing the interrupted link of space-ground laser communication based on the off-target amount of the downward light spot according to claim 1, wherein The preset iteration stop condition includes: The sum of the squares of the residuals of the residual vector converges; or The light spot miss distance is less than the preset convergence accuracy.

3. The method for reconstructing the disconnection of satellite-ground laser communication based on the downlink spot off-target amount according to claim 1, wherein, The correcting the servo pointing based on the light spot miss distance includes: Based on the light spot miss distance, use PID to correct the servo pointing.

4. A space-to-ground laser communication disconnection reconstruction device based on the off-target amount of the downward light spot, characterized in that, The space-ground laser communication disconnection reconstruction device uses the space-ground laser communication disconnection reconstruction method based on the downward light spot miss distance according to any one of claims 1-3. The device includes: A coarse tracking module, when a downward signal light spot appears in the coarse tracking field of view, controls the ground station to start the coarse tracking closed-loop process to establish a space-ground laser communication link; A light spot miss distance module, determines the light spot miss distance of the downward signal light spot, corrects the servo pointing based on the light spot miss distance, and records the light spot miss distance; Closing module, when the downlink signal light spot in the coarse tracking field of view disappears, close the coarse tracking closed loop to disconnect the space-ground laser communication link; Prediction module, based on the recorded light spot off-target amount, predict the predicted correction amount of the servo pointing at each moment after the downlink signal light spot disappears; Correction module, based on the predicted correction amount at each moment, correct the servo pointing to obtain the predicted corrected pointing of the servo at each moment; Search module, when a downlink signal light spot appears in the coarse tracking field of view, search for the predicted corrected pointing corresponding to the moment when the downlink signal light spot appears; Reconstruction module, based on the corresponding predicted corrected pointing, turn on the coarse tracking closed loop to reconstruct the space-ground laser communication link.

5. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the space-ground laser communication disconnection and reconstruction method based on the downlink light spot off-target amount as described in any one of claims 1 to 3 above.

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