Space laser communication method and system with automatic alignment function

Abstract

The invention provides a space laser communication method and system with an automatic alignment function, and the method comprises the steps: obtaining an image and point cloud data of an opposite-end device, constructing a feature vector according to the gray value, texture feature and contrast feature of each pixel point of the image, obtaining a binary image through the feature vector, and carrying out the recognition of the binary image. Carrying out stroke grouping on the binary images by taking a distance threshold as a judgment condition, fusing the mass center and the contour of each stroke group, the angle of a motor coded disc corresponding to beacon light of a home terminal device and distance information of the home terminal device and an opposite terminal device, and executing spiral scanning, the antenna of the signal light of the home terminal device is adjusted according to the position and angle corresponding to the received beacon light with the power reaching the preset value, and then automatic calibration is achieved. According to the invention, automatic calibration is realized based on the actual center of mass and the actual contour of the opposite end device, the actual angle of the motor code disc of the home end device and the principle that the beacon optical communication link is parallel to the signal optical communication link, manual intervention is not needed, and the alignment efficiency is improved on the premise of ensuring the accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of testing and verification of space laser terminals, and in particular to a space laser communication method and system with an automatic alignment function. Background Art

[0002] Space laser communication technology has gradually become an important technical means in space exploration activities due to its advantages of rich bandwidth resources, high transmission rate, large communication capacity and strong anti-interference ability. Space laser communication terminals need to be tested and verified during the development and debugging process, including precise alignment between space laser communication terminals in an indoor environment, so as to establish a reliable communication link to ensure efficient and stable transmission of information.

[0003] The precise alignment between space laser communication terminals needs to reach micron-level or even nanometer-level control accuracy. However, the indoor environment has limited space distance and is not an ideal optical environment. It is full of various optical obstacles that may cause laser beam scattering, refraction or absorption, making the already delicate alignment process even more complicated. Even debuggers with extremely high professional qualities and rich practical experience need to be extremely delicate and cautious during the debugging process. Each step needs to be repeatedly confirmed and adjusted, and debuggers need to perform a large number of repeated manual operations, including but not limited to adjusting the angles, positions and optical system parameters of the transmitter and receiver. Long-term repeated operations are not only time-consuming and laborious, but also increase the risk of operational errors and the difficulty of debugging.

[0004] Therefore, it is necessary to propose a space laser communication method and system with automatic alignment function to achieve fast and precise alignment in complex indoor environments to improve efficiency and accuracy. Summary of the invention

[0005] The present invention provides a space laser communication method and system with an automatic alignment function, which solves the problem in the prior art that "the efficiency and accuracy of automatic alignment between space laser communication terminals in an indoor environment need to be improved".

[0006] The present invention solves the technical problem through the following technical solutions:

[0007] A space laser communication method with automatic alignment function comprises the following steps:

[0008] (1) Obtaining the image and point cloud data of the current peer device;

[0009] (2) calculating the gray value, texture feature and contrast feature of each pixel in the image; constructing a feature vector by weighted sum of the gray value, texture feature and contrast feature; obtaining a segmentation threshold using a SVM training model based on the feature vector; and segmenting the image using the segmentation threshold to obtain a binary image;

[0010] For each ungrouped trip of the binary image, a preset distance threshold is used as a judgment condition for adjacency to group them to obtain each trip group; the centroid of each trip group is calculated to obtain the contour of each trip group; the centroid of each trip group, the contour and the motor encoder angle corresponding to the beacon light of the local device are used as the target position;

[0011] Calculating the distance between the local device and the current opposite device using the point cloud data;

[0012] (3) integrating the centroid, contour, motor encoder angle and distance of each of the above-mentioned trip groups, and determining the target area; transmitting the beacon light to perform a spiral scan on the target area; once the power of the received beacon light reaches a preset value, recording the current position of the received beacon light beam and the current angle of the motor encoder of the local device;

[0013] (4) adjusting the signal light antenna of the local device according to the current position and the current angle to achieve automatic alignment of the signal light transmitting antenna of the local device with the signal light receiving antenna of the current opposite device.

[0014] Furthermore, in step (2), the formula for calculating the gray value is:

[0015] Y=0.299*R+0.587*G+0.114*B, where Y is the grayscale value, R is the value of the red component, G is the value of the green component, and B is the value of the blue component.

[0016] Furthermore, in step (2), the step of calculating the texture feature is:

[0017] 1) Define a 3*3 texture window;

[0018] 2) taking pixels in the non-border pixel area of ​​the image according to the texture window size;

[0019] 3) Taking the grayscale value of the central pixel in the texture window as the grayscale threshold, traverse the 8 pixels outside the central pixel in the texture window clockwise or counterclockwise, and mark the current pixel as 1 when the grayscale value of the current pixel is greater than the grayscale threshold, otherwise mark it as 0, to obtain an 8-bit binary number;

[0020] 4) traversing the non-boundary pixel area in the image where texture feature calculation is not performed, and executing steps 2) and 3);

[0021] 5) Convert each obtained 8-bit binary number into a decimal number, and each decimal number is the texture feature of the image.

[0022] Furthermore, in step (2), the step of calculating the contrast feature is:

[0023] 1') Define a 3*3 contrast window;

[0024] 2') taking pixels in the non-border pixel area of ​​the image according to the contrast window size;

[0025] 3') In the contrast window, for each pixel, the contrast between the pixel and other pixels is calculated. The contrast measurement formula is: i, j are the coordinates of the eight pixels around the center pixel of the contrast window, Pij| is the grayscale value of the eight pixels around the center pixel of the contrast window; q is the pixel value of the center pixel of the contrast window, I(q) is the grayscale value of the center pixel of the contrast window, and ε is a constant;

[0026] 4') traverse the non-boundary pixel area in the image where contrast feature calculation has not been performed, and execute steps 2') and 3'); obtain more than one contrast measurement value, each contrast measurement value is the contrast feature of the image.

[0027] Furthermore, in step (2), the feature vector is F=0.25×Y+0.5×L+0.25×C, wherein Y is the grayscale value of the image, L is the texture feature of the image, and C is the contrast feature of the image.

[0028] Furthermore, in step (2), the step of grouping the binary images is:

[0029] a) preset distance threshold;

[0030] b) Create a trip group to store an ungrouped trip;

[0031] Iterate over all other ungrouped trips as the current trip;

[0032] If the x-axis or y-axis distance between the current trip and the last trip in the trip group is less than or equal to the distance threshold, the current trip is stored in the trip group and updated as the last trip in the trip group; otherwise, the current trip is not stored in the trip group;

[0033] c) Traverse the next ungrouped trip and execute step b) until all trips are stored in the corresponding trip group.

[0034] Furthermore, in step (2), the centroid of each trip group is calculated: Where n is the number of trips in the trip group, (x i ,y i ) is the starting position of the i-th stroke, w i is the width of the ith stroke, h i is the height of the ith stroke.

[0035] Furthermore, in step (3), the spiral scanning step is:

[0036] a') taking the geometric center of the target area as the initial scanning point and setting the initial radius and initial rotation step of the spiral scan in accordance with the principle of covering the outline of each stroke group;

[0037] b') Generate a spiral trajectory using the spiral equation r=a+b×△θ in polar coordinates, where r is the scanning radius, a is the distance between the initial scanning point and the center of the polar coordinates, b is the spacing of the control spiral line, and △θ is the step angle.

[0038] Furthermore, a space laser communication system with automatic alignment function for running the above communication method comprises a local device and at least one opposite device; the local device and each opposite device establish a communication link in a time-sharing manner;

[0039] The local device includes a local two-axis servo turntable control module, a local DSP processor, a local laser radar module, a local camera module, a local beacon light transmitting module, a local beacon light receiving module, a local signal light transmitting module and a local signal light receiving module;

[0040] In each opposite-end device, the opposite-end device includes an opposite-end two-axis servo turntable control module, an opposite-end DSP processor, an opposite-end laser radar module, an opposite-end camera module, an opposite-end beacon light transmitting module, an opposite-end beacon light receiving module, an opposite-end signal light transmitting module, and an opposite-end signal light receiving module;

[0041] The local camera module provides images for the local DSP processor; the local laser radar module provides point cloud data for the local DSP processor; the local beacon light transmitting module transmits beacon light under the control of the local DSP processor; the local beacon light receiving module receives the beacon light of the opposite device in time-sharing mode and inputs it to the local DSP processor; the local signal light transmitting module transmits signal light under the control of the local DSP processor; the local signal light receiving module inputs the received signal to the local DSP processor and the external optical fiber; the local DSP signal processor executes steps (1), (2), and (3); the local two-axis servo turntable control module executes step (4);

[0042] The structure and working principle of the opposite-end device are the same as those of the local-end device.

[0043] The advantages and effects of the present invention are:

[0044] The image of the opposite device is obtained through the camera module, and the point cloud data of the opposite device is obtained through the laser radar module. A feature vector is constructed for the image with the gray value, texture feature and contrast feature of each pixel point, and a segmentation threshold is obtained through the feature vector to segment the image to obtain a binary image. The binary image is grouped with the distance threshold as the judgment condition, and then the centroid, contour and motor code disk angle corresponding to the beacon light of the local device of each stroke group are obtained. In combination with the distance information between the local device and the opposite device provided by the point cloud data, a spiral scan is performed to adjust the antenna of the signal light of the local device according to the position and angle corresponding to the beacon light whose power reaches the preset value, so as to realize automatic calibration. The present invention adopts an adaptive multi-feature fusion threshold segmentation method and a stroke group coding algorithm to detect the target, and realizes automatic calibration based on the actual centroid, actual contour, actual angle of the motor code disk of the opposite device, and the principle that the beacon light communication link is parallel to the signal light communication link, without human intervention, and improves the alignment efficiency while ensuring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a principle block diagram of the automatic alignment method of the present invention.

[0046] Figure 2 Schematic diagram of the spiral scanning trajectory.

[0047] Figure 3 This is a block diagram of the structural principle of establishing a communication link between a local device and a remote device in the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

[0049] A space laser communication method with automatic alignment function comprises the following steps:

[0050] (1) Obtaining the image and point cloud data of the current peer device;

[0051] (2) calculating the gray value, texture feature and contrast feature of each pixel in the image; constructing a feature vector by weighted sum of the gray value, texture feature and contrast feature; obtaining a segmentation threshold using a SVM training model based on the feature vector; and segmenting the image using the segmentation threshold to obtain a binary image;

[0052] For each ungrouped trip of the binary image, a preset distance threshold is used as a judgment condition for adjacency to group them to obtain each trip group; the centroid of each trip group is calculated to obtain the contour of each trip group; the centroid of each trip group, the contour and the motor encoder angle corresponding to the beacon light of the local device are used as the target position;

[0053] Calculating the distance between the local device and the current opposite device using the point cloud data;

[0054] (3) integrating the centroid, contour, motor encoder angle and distance of each of the above-mentioned trip groups, and determining the target area; transmitting the beacon light to perform a spiral scan on the target area; once the power of the received beacon light reaches a preset value, recording the current position of the received beacon light beam and the current angle of the motor encoder of the local device;

[0055] (4) adjusting the signal light antenna of the local device according to the current position and the current angle to achieve automatic alignment of the signal light transmitting antenna of the local device with the signal light receiving antenna of the current opposite device.

[0056] The structural principles and working principles of the local device and each opposite-end device are the same. One space laser communication terminal is regarded as the local end, and the other space laser communication terminals are regarded as opposite-end devices.

[0057] The principle block diagram of the automatic alignment method of the present invention is as follows: Figure 1 After the local device and each opposite device are powered on, the local device performs a 360-degree rotation scan, and obtains the image and point cloud data of the current opposite device as described in step (1); extracts the position and outline of the current opposite device, the motor code disk angle corresponding to the beacon light of the local device, and the distance information between the local device and the current opposite device as described in step (2); fuses the data as described in steps (3) and (4), emits beacon light in the target area for spiral scanning, and automatically adjusts the signal light antenna according to the position and angle of the current beacon light when the received beacon light reaches the preset power, so as to achieve automatic calibration.

[0058] The image in step (1) reflects the position and outline of the current opposite device; the point cloud data in step (1) refers to a set of vectors in a three-dimensional coordinate system, and the distance between the local device and the current opposite device can be calculated through the point cloud data.

[0059] In step (2), the formula for calculating the gray value is Y=0.299*R+0.587*G+0.114*B, where Y is the gray value, R is the value of the red component, G is the value of the green component, and B is the value of the blue component.

[0060] In step (2), the steps of calculating texture features are:

[0061] 1) Define a 3*3 texture window;

[0062] 2) taking pixels in the non-border pixel area of ​​the image according to the texture window size;

[0063] 3) Taking the grayscale value of the central pixel in the texture window as the grayscale threshold, traverse the 8 pixels outside the central pixel in the texture window clockwise or counterclockwise, and mark the current pixel as 1 when the grayscale value of the current pixel is greater than the grayscale threshold, otherwise mark it as 0, to obtain an 8-bit binary number;

[0064] 4) traversing the non-boundary pixel area in the image where texture feature calculation is not performed, and executing steps 2) and 3);

[0065] 5) Convert each obtained 8-bit binary number into a decimal number, and each decimal number is the texture feature of the image.

[0066] In step (2), the steps of calculating the contrast feature are:

[0067] 1') Define a 3*3 contrast window;

[0068] 2') taking pixels in the non-border pixel area of ​​the image according to the contrast window size;

[0069] 3') In the contrast window, for each pixel, the contrast between the pixel and other pixels is calculated. The contrast measurement formula is: Wherein, i, j are the coordinates of the eight pixels around the center pixel of the contrast window, Pij| is the grayscale value of the eight pixels around the center pixel of the contrast window; q is the pixel value of the center pixel of the contrast window, I(q) is the grayscale value of the center pixel of the contrast window, and ε is a constant;

[0070] 4') traverse the non-boundary pixel area in the image where contrast feature calculation has not been performed, and execute steps 2') and 3'); obtain more than one contrast measurement value, each contrast measurement value is the contrast feature of the image.

[0071] In step (2), the feature vector is F=0.25×Y+0.5×L+0.25×C, where Y is the grayscale value of the image, L is the texture feature of the image, and C is the contrast feature of the image.

[0072] Support vector machine (SVM) is a supervised machine learning algorithm that classifies data by finding the optimal line or hyperplane to maximize the distance between each category in N-dimensional space. The SVM training model in step (2) is a prior art. The feature vector is input into the SVM training model to obtain the desired segmentation threshold. When segmenting the image, pixels greater than the segmentation threshold are set to 255, and pixels less than the segmentation threshold are set to 0, resulting in a binary image.

[0073] The run group coding algorithm is usually applied to image compression. The present invention applies the algorithm to analyze binary images, and then extracts the centroid and contour information after run grouping, which can extract the effective features of the opposite device to the greatest extent possible, improve the accuracy of target detection, and further improve the accuracy of automatic alignment, and can also realize accurate detection of multiple opposite devices.

[0074] In step (2), the step of grouping the binary images is as follows:

[0075] a) preset distance threshold;

[0076] b) Create a trip group to store an ungrouped trip;

[0077] Iterate over all other ungrouped trips as the current trip;

[0078] If the x-axis or y-axis distance between the current trip and the last trip in the trip group is less than or equal to the distance threshold, the current trip is stored in the trip group and updated as the last trip in the trip group; otherwise, the current trip is not stored in the trip group;

[0079] c) Traverse the next ungrouped trip and execute step b) until all trips are stored in the corresponding trip group.

[0080] In step (2), the centroid of each trip group is calculated: Where n is the number of trips in the trip group, (x i ,y i ) is the starting position of the i-th stroke, w i is the width of the ith stroke, h i is the height of the ith stroke.

[0081] In step (2), the outline of the stroke group, i.e., the length and width of the stroke group, the length refers to the pixel points between the maximum value and the minimum value of the stroke group in the x direction, and the width refers to the pixel points between the maximum value and the minimum value of the stroke group in the y direction.

[0082] In step (2), the motor code disk angle corresponding to the beacon light of the local device is directly read from the local two-axis servo turntable.

[0083] In step (3), the centroid, contour, motor encoder angle and distance corresponding to the beacon light of the local device of each stroke group are unified into the same coordinate system for fusion. The fused target information is the collection of various data.

[0084] In step (3), the steps of spiral scanning are:

[0085] a') taking the geometric center of the target area as the initial scanning point and setting the initial radius and initial rotation step of the spiral scan in accordance with the principle of covering the outline of each stroke group;

[0086] b') Generate a spiral trajectory using the spiral equation r=a+b×△θ in polar coordinates, where r is the scanning radius, a is the distance between the initial scanning point and the center of the polar coordinates, b is the spacing of the control spiral line, and △θ is the step angle. The schematic diagram of the spiral scanning trajectory of the present invention is shown in FIG. Figure 2 As shown, M is the center of mass position of the current opposite device, c is the center point of the polar coordinates, and A and B represent the two points corresponding to △θ on the spiral trajectory.

[0087] In step (3), taking one local device and one opposite device as an example, once the power of the beacon light received by the local device reaches a preset value, and the power of the beacon light received by the opposite device also reaches a preset value, the local device records the current position of the beacon light beam emitted by the local device and the current angle of the motor code disk, and the opposite device records the current position of the beacon light beam emitted by the opposite device and the current angle of the motor code disk.

[0088] The automatic alignment in step (4) includes the capture process and the precise alignment process. Once the beacon light laser beam is received at the local device, the position, angle and intensity information of the beacon light are immediately recorded. Usually, the intensity is at least -35dbm at this time. After successful capture, the antenna of the signal light can be adjusted according to the position and angle information to achieve precise alignment.

[0089] After the automatic alignment is completed, the optical axes of the transmitted light and beacon light laser beams are parallel.

[0090] The space laser communication system with automatic alignment function that runs the above steps includes one local device and at least one opposite device; the local device and each opposite device establish a communication link in a time-sharing manner;

[0091] The local device includes a local two-axis servo turntable control module, a local DSP processor, a local laser radar module, a local camera module, a local beacon light transmitting module, a local beacon light receiving module, a local signal light transmitting module and a local signal light receiving module;

[0092] In each opposite-end device, the opposite-end device includes an opposite-end two-axis servo turntable control module, an opposite-end DSP processor, an opposite-end laser radar module, an opposite-end camera module, an opposite-end beacon light transmitting module, an opposite-end beacon light receiving module, an opposite-end signal light transmitting module, and an opposite-end signal light receiving module; the structure of the opposite-end device is the same as the structure and working principle of the local device;

[0093] The local camera module provides images for the local DSP processor; the local laser radar module provides point cloud data for the local DSP processor; the local beacon light transmitting module transmits beacon light under the control of the local DSP processor; the local beacon light receiving module receives the beacon light of the opposite device in time-sharing mode and inputs it into the local DSP processor; the local signal light transmitting module transmits signal light under the control of the local DSP processor; the local signal light receiving module inputs the signal into the local DSP processor and the external optical fiber after receiving the signal; the local DSP signal processor executes steps (1), (2), and (3); the local two-axis servo turntable control module executes step (4). The structural principle block diagram of a local device establishing a communication link with a opposite device is shown in FIG. Figure 3 described.

[0094] In the local device, the local beacon light transmitting module is used to generate the beacon light to be tracked and aligned, the local beacon light receiving module is used to capture and track the beacon light generated by the opposite device, the local signal light transmitting module is used to generate signal light that can transmit information, the local signal light receiving module is used to receive the transmitted light signal, and the local two-axis servo turntable performs scanning, tracking and antenna alignment functions.

[0095] Furthermore, the local device also includes a local two-axis servo turntable body, and the local two-axis servo turntable control module, the local DSP processor, the local laser radar module, the local camera module, the local beacon light transmitting module, the local beacon light receiving module, the local signal light transmitting module and the local signal light receiving module are installed on the local two-axis servo turntable body and rotate with the local two-axis servo turntable body, and the local two-axis servo turntable body can control the local beacon light transmitting module, the local beacon light receiving module, the local signal light transmitting module and the antenna of the local signal light receiving module in the two-axis direction.

[0096] Furthermore, in each opposite-end device, the opposite-end device includes an opposite-end two-axis servo turntable body, and each opposite-end device has the same structural principle and working principle as the local device.

[0097] The two-axis servo turntable mainly includes a two-axis servo turntable body and a two-axis servo turntable control module. The structural principle and working principle of the two-axis servo turntable are existing technologies. The two-axis servo turntable body consists of two mutually perpendicular rotating axes, which are responsible for precise angle adjustment in the horizontal and vertical directions respectively. High-precision position, speed and acceleration control are achieved through a closed-loop control system using the FOC (Field-Oriented Control) algorithm. Once the local device successfully captures the position of the beacon light emitted by the opposite device, it is converted into a feedback signal of the code disk (encoder) on the two-axis servo turntable, and the deviation angle is calculated to control the azimuth and pitch direction of the turntable body, thereby aligning the transceiver light beams.

Claims

1. A space laser communication method with automatic alignment function, characterized in that: The steps include: (1) Obtaining the image and point cloud data of the current peer device; (2) calculating the gray value, texture feature and contrast feature of each pixel in the image; constructing a feature vector by weighted sum of the gray value, texture feature and contrast feature; obtaining a segmentation threshold using a SVM training model based on the feature vector; and segmenting the image using the segmentation threshold to obtain a binary image; For each ungrouped trip of the binary image, grouping is performed using a preset distance threshold as a judgment condition of adjacency to obtain each trip group; Calculate the centroid of each travel group and obtain the outline of each travel group; take the centroid, outline of each travel group and the motor encoder angle corresponding to the beacon light of the local device as the target position; Calculating the distance between the local device and the current opposite device using the point cloud data; (3) integrating the centroid, contour, motor encoder angle and distance of each of the above-mentioned trip groups, and determining the target area; transmitting the beacon light to perform a spiral scan on the target area; once the power of the received beacon light reaches a preset value, recording the current position of the received beacon light beam and the current angle of the motor encoder of the local device; (4) adjusting the signal light antenna of the local device according to the current position and the current angle to achieve automatic alignment of the signal light transmitting antenna of the local device with the signal light receiving antenna of the current opposite device.

2. The space laser communication method with automatic alignment function according to claim 1, characterized in that: In step (2), the formula for calculating the gray value is Y=0.299*R+0.587*G+0.114*B, where Y is the gray value, R is the value of the red component, G is the value of the green component, and B is the value of the blue component.

3. The space laser communication method with automatic alignment function according to claim 2, characterized in that: In step (2), the steps of calculating texture features are: 1) Define a 3*3 texture window; 2) taking pixels in the non-border pixel area of ​​the image according to the texture window size; 3) Taking the grayscale value of the central pixel in the texture window as the grayscale threshold, traverse the 8 pixels outside the central pixel in the texture window clockwise or counterclockwise, and mark the current pixel as 1 when the grayscale value of the current pixel is greater than the grayscale threshold, otherwise mark it as 0, to obtain an 8-bit binary number; 4) traversing the non-boundary pixel area in the image where texture feature calculation is not performed, and executing steps 2) and 3); 5) Convert each obtained 8-bit binary number into a decimal number, and each decimal number is the texture feature of the image.

4. The space laser communication method with automatic alignment function according to claim 3, characterized in that: In step (2), the steps of calculating the contrast feature are: 1') Define a 3*3 contrast window; 2') taking pixels in the non-border pixel area of ​​the image according to the contrast window size; 3') In the contrast window, for each pixel, the contrast between the pixel and other pixels is calculated. The contrast measurement formula is: i, j are the coordinates of the eight pixels around the center pixel of the contrast window, Pij| is the grayscale value of the eight pixels around the center pixel of the contrast window; q is the pixel value of the center pixel of the contrast window, I(q) is the grayscale value of the center pixel of the contrast window, and ε is a constant; 4') traverse the non-boundary pixel area in the image where contrast feature calculation has not been performed, and execute steps 2') and 3'); obtain more than one contrast measurement value, each contrast measurement value is the contrast feature of the image.

5. The space laser communication method with automatic alignment function according to claim 4, characterized in that: In step (2), the feature vector is F=0.25×Y+0.5×L+0.25×C, where Y is the grayscale value of the image, L is the texture feature of the image, and C is the contrast feature of the image.

6. The space laser communication method with automatic alignment function according to claim 1, characterized in that: In step (2), the step of grouping the binary images is as follows: a) preset distance threshold; b) Create a trip group to store an ungrouped trip; Iterate over all other ungrouped trips as the current trip; If the x-axis or y-axis distance between the current trip and the last trip in the trip group is less than or equal to the distance threshold, the current trip is stored in the trip group and updated as the last trip in the trip group; otherwise, the current trip is not stored in the trip group; c) Traverse the next ungrouped trip and execute step b) until all trips are stored in the corresponding trip group.

7. A space laser communication method with automatic alignment function according to claim 6, characterized in that: In step (2), the centroid of each trip group is calculated: Where n is the number of trips in the trip group, (x i ,y i ) is the starting position of the i-th stroke, w i is the width of the ith stroke, h i is the height of the ith stroke.

8. The space laser communication method with automatic alignment function according to claim 7, characterized in that: In step (3), the steps of spiral scanning are: a') taking the geometric center of the target area as the initial scanning point and setting the initial radius and initial rotation step of the spiral scan in accordance with the principle of covering the outline of each stroke group; b') Generate a spiral trajectory using the spiral equation r=a+b×△θ in polar coordinates, where r is the scanning radius, a is the distance between the initial scanning point and the center of the polar coordinates, b is the spacing of the control spiral line, and △θ is the step angle.

9. A space laser communication system with automatic alignment function for running the space laser communication method with automatic alignment function as claimed in any one of claims 1 to 8, characterized in that: It includes one local device and at least one opposite device; the local device and each opposite device establish a communication link in a time-sharing manner; The local device includes a local two-axis servo turntable control module, a local DSP processor, a local laser radar module, a local camera module, a local beacon light transmitting module, a local beacon light receiving module, a local signal light transmitting module and a local signal light receiving module; In each opposite-end device, the opposite-end device includes an opposite-end two-axis servo turntable control module, an opposite-end DSP processor, an opposite-end laser radar module, an opposite-end camera module, an opposite-end beacon light transmitting module, an opposite-end beacon light receiving module, an opposite-end signal light transmitting module, and an opposite-end signal light receiving module; The local camera module provides images for the local DSP processor; the local laser radar module provides point cloud data for the local DSP processor; the local beacon light transmitting module transmits beacon light under the control of the local DSP processor; the local beacon light receiving module receives the beacon light of the opposite device in time-sharing mode and inputs it to the local DSP processor; the local signal light transmitting module transmits signal light under the control of the local DSP processor; the local signal light receiving module inputs the received signal to the local DSP processor and the external optical fiber; the local DSP signal processor executes steps (1), (2), and (3); the local two-axis servo turntable control module executes step (4); The structure and working principle of the opposite-end device are the same as those of the local-end device.

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