Rapid correction method for on-orbit initial aiming error of laser communication terminal

Abstract

The invention discloses a rapid correction method for an on-orbit initial aiming error of a laser communication terminal, and relates to the technical field of satellite communication. Comprising the steps of calculating an initial direction of a laser communication terminal according to orbit and attitude information of double satellites; respectively performing thermal simulation and gravity simulation on the laser communication terminal by adopting a finite element simulation analysis method, and calculating to obtain installation deformation quantity caused by influence of a space thermal environment and a gravity environment; converting the installation type variable into a pointing error of the laser communication terminal to obtain a space thermal environment change correction and a gravity environment change correction; correcting position information of a target satellite pointed by the laser communication terminal through Beidou short message information to obtain a space orbit error correction amount; and according to the change correction and the space orbit error correction, performing comprehensive correction on the initial direction of the laser communication terminal. The method is used for solving the problems of long initial link establishment time, low precision and poor working efficiency after a laser communication terminal enters an orbit.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and in particular to a method for quickly correcting the initial aiming error of a laser communication terminal on orbit. Background Art

[0002] Space laser communication is a communication method that uses laser beams as carriers to transmit data information such as images, voices, and signals in free space. Compared with traditional microwave communication, space laser communication has the advantages of fast transmission rate, large communication capacity, strong anti-electromagnetic interference performance, high confidentiality, etc., and its communication terminal is small in size, low in power consumption, and good in practicality. The development and breakthrough of laser communication technology can solve the bottleneck problem of existing space transmission, and is of great significance to enhancing the real-time and security of free space information transmission. In the European SILEX program, EDRS program, Japan's OICETS and domestic Beidou and practical projects, on-orbit test verification of satellite-to-ground and inter-satellite space laser communications at different rates has been achieved many times. Currently, large-scale constellations are under construction, such as the STAR-LINK program of the United States SPACE-X, China's satellite Internet constellation, various remote sensing constellations, etc., which have clearly identified space laser communication as an inter-satellite networking method. After the satellite enters orbit, due to the existence of pointing errors, the laser communication terminal needs to adopt a scanning method to establish a link, maintain and communicate with the target, so the initial pointing error on orbit will have a great impact on the initial link establishment time. However, the installation error of the terminal caused by the temperature and gravity changes after entering orbit, as well as the orbital error of the satellite position during link establishment, will lead to a large uncertainty area during link establishment. At the same time, the beam width of laser communication is extremely narrow. The beam width of the beacon-free capture currently in engineering use is only tens of μrad. It takes a long time to achieve wide-area scanning with an extremely narrow beam width, which will seriously affect the laser capture link establishment.

[0003] In the domestic public on-orbit tests, due to the large initial aiming error, the initial link establishment time was several days on average, and the initial link establishment time for some models reached nearly one month, seriously affecting the performance of the laser communication terminal and the satellite on-orbit. Summary of the invention

[0004] The present invention aims to provide a method for quickly correcting the initial aiming error of a laser communication terminal on orbit, so as to solve the problems of long initial link establishment time, low precision and poor working efficiency after the laser communication terminal enters orbit.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] On the one hand, this specification provides a method for quickly correcting the initial aiming error of a laser communication terminal on orbit, comprising:

[0007] Calculate the initial pointing direction of the laser communication terminal based on the orbit and attitude information of the binary satellites;

[0008] Finite element simulation analysis method is used to perform thermal simulation and gravity simulation on the laser communication terminal, and the installation deformation caused by the space thermal environment and gravity environment is calculated;

[0009] The installation deformation caused by the space thermal environment and the gravity environment are respectively converted into the pointing error of the laser communication terminal to obtain the space thermal environment change correction amount and the gravity environment change correction amount;

[0010] Through Beidou short message information, the position information of the target star pointed by the laser communication terminal is corrected to obtain the space orbit error correction value;

[0011] The initial pointing direction of the laser communication terminal is comprehensively corrected according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount.

[0012] On the other hand, this specification also provides a device for quickly correcting the initial aiming error of a laser communication terminal on orbit, comprising:

[0013] The initial pointing calculation module is used to calculate the initial pointing of the laser communication terminal according to the orbit and attitude information of the binary satellites;

[0014] The installation deformation calculation module is used to use the finite element simulation analysis method to perform thermal simulation and gravity simulation on the laser communication terminal, and calculate the installation deformation caused by the influence of the space thermal environment and gravity environment;

[0015] An installation deformation correction module is used to convert the installation deformation caused by the space thermal environment and the gravity environment into the pointing error of the laser communication terminal, and obtain the space thermal environment change correction amount and the gravity environment change correction amount;

[0016] The orbit error correction module is used to correct the target satellite position information pointed by the laser communication terminal through Beidou short message information to obtain the space orbit error correction value;

[0017] The comprehensive pointing correction module is used to comprehensively correct the initial pointing of the laser communication terminal according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount.

[0018] On the other hand, this specification also provides an electronic device,

[0019] Processor; and

[0020] A memory arranged to store computer executable instructions which, when executed, cause the processor to perform the steps of a method as claimed in any one of the preceding claims.

[0021] On the other hand, this specification also provides a storage medium,

[0022] The storage medium stores a processing program for quickly correcting the initial aiming error of the laser communication terminal on-orbit, and when the processing program for quickly correcting the initial aiming error of the laser communication terminal on-orbit is executed by the processor, the method steps as described in any one of the above claims are implemented.

[0023] Based on the above technical solution, this specification can achieve the following technical effects:

[0024] In order to meet the demand for rapid link establishment after the laser communication terminal enters orbit, the present invention proposes a method for rapid correction of the initial aiming error of the laser communication terminal on orbit, specifically: (1) Through force and thermal analysis and finite element simulation of the laser communication terminal installation surface, the installation deformation caused by the orbital dynamic environment and the external heat flow environment after the product enters orbit is quantified, thereby calibrating the initial pointing error caused by the installation deformation; (2) By adding Beidou short message information, the high-precision position information of the opposite satellite can be obtained in real time, replacing the original orbit extrapolation method, and then calibrating the initial pointing error caused by the orbit error. Based on the above two calibration methods, the initial aiming error of the laser terminal after entering orbit can be greatly reduced, the uncertainty area of ​​the scan can be reduced, and the initial link establishment time of the laser communication terminal after entering orbit can be significantly reduced, thereby improving the overall efficiency of the laser communication terminal and the constellation, and providing an effective technical means for the engineering application of laser communication terminals on orbit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of a method for quickly correcting the initial aiming error of a laser communication terminal on-orbit provided in Example 1 of this specification;

[0026] Figure 2 This is a schematic diagram of a system flow for rapid correction of initial aiming error of a laser communication terminal on-orbit provided in Example 1 of this specification;

[0027] Figure 3 It is a schematic diagram of the flow chart of the spatial temperature environment change correction provided in Example 1 of this specification;

[0028] Figure 4 It is a schematic diagram of the simulation of the correction of the spatial temperature environment change provided in Example 1 of this specification;

[0029] Figure 5 It is a schematic diagram of the flow of space gravity change correction provided in Example 1 of this specification;

[0030] Figure 6 It is a schematic diagram of the simulation of space gravity change correction provided in Example 1 of this specification;

[0031] Figure 7 It is a schematic diagram of the working principle of the Beidou short message location transmission system provided in Example 1 of this specification;

[0032] Figure 8 It is a schematic diagram of the working principle of the Beidou short message location transmission system provided in Example 2 of this specification. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0034] It should be noted that, in order to clearly explain the content of the present invention, the present invention specifically cites multiple embodiments to further illustrate different implementations of the present invention, wherein the multiple embodiments are enumerated rather than exhaustive. In addition, for the sake of brevity of explanation, the contents mentioned in the previous embodiments are often omitted in the subsequent embodiments. Therefore, the contents not mentioned in the subsequent embodiments can refer to the previous embodiments accordingly.

[0035] Example 1

[0036] Please refer to Figure 1 , Figure 2 , Figure 1 FIG. 1 is a flow chart of a method for quickly correcting an initial aiming error of a laser communication terminal on-orbit provided by this embodiment. Figure 2 The figure shows a schematic diagram of a system flow for rapid correction of initial aiming error of a laser communication terminal on-orbit provided by this embodiment. The method specifically comprises the following steps:

[0037] Step 102: Calculate the initial pointing direction of the laser communication terminal according to the orbit and attitude information of the binary satellites.

[0038] It should be noted that one implementation of step 102 may be:

[0039] After the laser terminal enters orbit, the initial pointing is calculated based on the orbit and attitude information of the binary satellite.

[0040] Step 104: Use a finite element simulation analysis method to perform thermal simulation and gravity simulation on the laser communication terminal, respectively, and calculate the installation deformation caused by the influence of the space thermal environment and gravity environment.

[0041] It should be noted that one implementation of step 104 may be:

[0042] The deformation caused by the space thermal environment is calculated by thermal simulation. The specific method is: consider the influence of the heat flow outside the space and the thermal deformation caused by the heat radiation inside the cabin on the installation benchmark, and model and analyze it in the finite element software. Evenly select temperature measurement points near the installation point, such as Figure 4 As shown in the figure. At different positions on the track, due to the different track lighting conditions and the temperature of the surrounding equipment, the temperature of each point will change periodically with the change of the track cycle, and the temperature gradient between each point will also change accordingly. The change in temperature gradient will cause the cabin plate to deform, which will in turn cause the change in the pointing angle of the laser terminal. The specific change can be calculated through simulation software.

[0043] The specific solution process is as follows Figure 3 As shown, including:

[0044] (a) Multiple temperature measurement points are evenly arranged around the laser communication terminal installation surface, generally more than 6;

[0045] (b) After the terminal enters orbit, temperature data is collected based on the deployed temperature measurement points;

[0046] (c) In the ANSYS finite element software, the deformation of the mounting surface caused by temperature changes is calculated based on the mounting surface material and product structure modeling.

[0047] According to the gravity environment, the deformation is calculated. The Altair super engineering software is used to perform finite element modeling analysis on the entire satellite assembly model. Fixture constraints are added to the satellite-rocket interface, and gravity acceleration is added. After solving, the coordinates of the four nodes on the laser terminal installation surface are extracted respectively. The angle change of the installation surface normal is obtained by fitting the coordinate surface, so as to judge the influence of gravity on the installation accuracy of the laser communication terminal. Figure 6 shown.

[0048] The specific solution process is as follows Figure 5 As shown, including:

[0049] (a) Establish a structural model in the Altair super engineering software;

[0050] (b) Input space gravity changes and simulate structural deformation.

[0051] Step 106: Convert the installation deformation caused by the space thermal environment and the gravity environment into the pointing error of the laser communication terminal to obtain the space thermal environment change correction amount and the gravity environment change correction amount.

[0052] It should be noted that one implementation of step 106 may be:

[0053] The installation deformation caused by the space thermal environment and gravity environment is converted into pointing error.

[0054] Step 108: Correct the target star position information pointed to by the laser communication terminal through Beidou short message information to obtain the space orbit error correction value.

[0055] It should be noted that one implementation of step 108 may be:

[0056] The target star position information pointed by the laser is corrected through Beidou short message information, such as Figure 7 shown.

[0057] Low-orbit satellite A is equipped with laser communication terminal A and Beidou short message payload A; low-orbit satellite B is equipped with laser communication terminal B and Beidou short message payload B.

[0058] The low-orbit satellite B is taken as the target satellite. The real-time position information of the low-orbit satellite B is sent to the Beidou satellite through the Beidou short message payload B; the Beidou satellite sends the real-time position information of the low-orbit satellite B to the Beidou short message payload A through the Beidou ground station, thereby realizing the real-time acquisition of the position of the B satellite by the A satellite, and thus calculating the space orbit error correction of the laser communication terminal A.

[0059] Furthermore, the low-orbit satellite A is taken as the target satellite. The real-time position information of the low-orbit satellite A is sent to the Beidou satellite through the Beidou short message payload A; the Beidou satellite sends the real-time position information of the low-orbit satellite A to the Beidou short message payload B through the Beidou ground station, so that the B satellite can obtain the position of the A satellite in real time, and thus calculate the space orbit error correction of the laser communication terminal B.

[0060] Based on this, the pointing accuracy of the target star is improved, and the communication efficiency between laser communication terminals is improved.

[0061] Step 110: Perform a comprehensive correction on the initial pointing direction of the laser communication terminal according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount.

[0062] It should be noted that one implementation of step 110 may be:

[0063] The correction values ​​in steps 104-108 are combined to correct the initial aiming angle.

[0064] Furthermore, according to the correction amount of the initial aiming angle, the laser communication terminal can quickly capture the target, and make a final correction based on the capture result.

[0065] In order to verify the on-orbit rapid calibration method of the laser communication terminal aiming error, the following simulation and test examples of a certain type of laser communication terminal are given. A certain type of intersatellite laser communication system has a communication distance of 4800km. The laser terminal weighs 8kg and is evenly installed in a circle on the satellite through 8 mounting screws. The positioning accuracy and time delay error of each BD short message carried by the satellite are estimated as 50m. For the space thermal environment correction stage, the linear expansion coefficient of the honeycomb plate is 1.7e-6 / ℃, the diameter of the honeycomb plate constraint section is 30cm, and the orbital altitude is 1200km. The simulation results show that within an orbital variation range, the deformation scalar value caused by the change in temperature gradient is approximately between 1.6mrad and 2.8mrad. The temperature gradient is the smallest on the shady side, which is 1.6mrad, and the temperature gradient is the largest on the sunny side, which is 2.8mrad. For the gravity environment correction stage, different material properties are selected in the simulation for calculation, and the change value is between 200-300μrad. For the space orbit error correction stage, the positioning accuracy of the Beidou short message system is 50m, and the orbit recursion accuracy is 2km, so the pointing accuracy can be improved by about 400μrad. In summary, the initial aiming and pointing accuracy correction is generally between 2.2-3.5mrad.

[0066] In summary, in order to meet the demand for rapid link establishment after the laser communication terminal enters orbit, the present invention proposes a method for rapid correction of the initial aiming error of the laser communication terminal on orbit, specifically: (1) Through force, thermal analysis and finite element simulation of the laser communication terminal installation surface, the installation deformation caused by the orbital dynamic environment and the external heat flow environment after the product enters orbit is quantified, thereby calibrating the initial pointing error caused by the installation deformation; (2) By adding Beidou short message information, the high-precision position information of the opposite satellite can be obtained in real time, replacing the original orbit extrapolation method, and then calibrating the initial pointing error caused by the orbit error. Based on the above two calibration methods, the initial aiming error of the laser terminal after entering orbit can be greatly reduced, the uncertainty area of ​​the scan can be reduced, and the initial link establishment time of the laser communication terminal after entering orbit can be significantly reduced, thereby improving the overall efficiency of the laser communication terminal and the constellation, and providing an effective technical means for the engineering application of laser communication terminals on orbit.

[0067] Example 2

[0068] Please refer to Figure 8 , Figure 8 The figure shows a schematic diagram of a device for quickly correcting the initial aiming error of a laser communication terminal on-orbit provided by this embodiment. The device comprises:

[0069] An initial pointing calculation module 202 is used to calculate the initial pointing of the laser communication terminal according to the orbit and attitude information of the binary satellites;

[0070] The installation deformation calculation module 204 is used to use the finite element simulation analysis method to perform thermal simulation and gravity simulation on the laser communication terminal, and calculate the installation deformation caused by the influence of the space thermal environment and gravity environment;

[0071] The installation deformation correction module 206 is used to convert the installation deformation caused by the space thermal environment and the gravity environment into the pointing error of the laser communication terminal, and obtain the space thermal environment change correction amount and the gravity environment change correction amount;

[0072] The orbit error correction module 208 is used to correct the position information of the target star pointed by the laser communication terminal through the Beidou short message information to obtain the space orbit error correction value;

[0073] The comprehensive pointing correction module 210 is used to comprehensively correct the initial pointing of the laser communication terminal according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount.

[0074] Optionally, the track error correction module further includes a fast communication submodule, which is specifically used to:

[0075] The low-orbit satellite B is taken as the target satellite. The real-time position information of the low-orbit satellite B is sent to the Beidou satellite through the Beidou short message payload B; the Beidou satellite sends the real-time position information of the low-orbit satellite B to the Beidou short message payload A through the Beidou ground station, thereby realizing the real-time acquisition of the position of the B satellite by the A satellite, and thus calculating the space orbit error correction of the laser communication terminal A.

[0076] Furthermore, the low-orbit satellite A is taken as the target satellite. The real-time position information of the low-orbit satellite A is sent to the Beidou satellite through the Beidou short message payload A; the Beidou satellite sends the real-time position information of the low-orbit satellite A to the Beidou short message payload B through the Beidou ground station, so that the B satellite can obtain the position of the A satellite in real time, and thus calculate the space orbit error correction of the laser communication terminal B.

[0077] Based on this, the pointing accuracy of the target star is improved, and the communication efficiency between laser communication terminals is improved.

[0078] In summary, in order to meet the demand for rapid link establishment after the laser communication terminal enters orbit, the present invention proposes a method for rapid correction of the initial aiming error of the laser communication terminal on orbit, specifically: (1) Through force, thermal analysis and finite element simulation of the laser communication terminal installation surface, the installation deformation caused by the orbital dynamic environment and the external heat flow environment after the product enters orbit is quantified, thereby calibrating the initial pointing error caused by the installation deformation; (2) By adding Beidou short message information, the high-precision position information of the opposite satellite can be obtained in real time, replacing the original orbit extrapolation method, and then calibrating the initial pointing error caused by the orbit error. Based on the above two calibration methods, the initial aiming error of the laser terminal after entering orbit can be greatly reduced, the uncertainty area of ​​the scan can be reduced, and the initial link establishment time of the laser communication terminal after entering orbit can be significantly reduced, thereby improving the overall efficiency of the laser communication terminal and the constellation, and providing an effective technical means for the engineering application of laser communication terminals on orbit.

[0079] Example 3

[0080] In another feasible embodiment, this embodiment provides a device for quickly correcting the initial aiming error of a laser communication terminal on orbit, and the device may specifically include:

[0081] Processor; and

[0082] A memory arranged to store computer executable instructions, which, when executed, cause the processor to perform the steps in any of the above method embodiments.

[0083] Example 4

[0084] In another feasible embodiment, this embodiment provides a storage medium for rapid correction of initial aiming error of a laser communication terminal on orbit, and the storage medium may specifically include:

[0085] The storage medium stores a processing program for quickly correcting the initial aiming error of the laser communication terminal on-orbit. When the processing program for quickly correcting the initial aiming error of the laser communication terminal on-orbit is executed by the processor, the steps in any of the above method embodiments are implemented.

[0086] The above description is only an embodiment of the present specification and is not intended to limit the present specification. For those skilled in the art, the present specification can be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present specification should be included in the scope of the claims of the present specification.

Claims

1. A method for quickly correcting the initial aiming error of a laser communication terminal on orbit, characterized in that: include: Calculate the initial pointing direction of the laser communication terminal based on the orbit and attitude information of the binary satellites; Finite element simulation analysis method is used to perform thermal simulation and gravity simulation on the laser communication terminal, and the installation deformation caused by the space thermal environment and gravity environment is calculated; The installation deformation caused by the space thermal environment and the gravity environment are respectively converted into the pointing error of the laser communication terminal to obtain the space thermal environment change correction amount and the gravity environment change correction amount; Through Beidou short message information, the position information of the target star pointed by the laser communication terminal is corrected to obtain the space orbit error correction value; The initial pointing direction of the laser communication terminal is comprehensively corrected according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount.

2. The method according to claim 1, characterized in that: The finite element simulation analysis method is used to perform thermal simulation and gravity simulation on the laser communication terminal, and the installation deformation caused by the influence of the space thermal environment and gravity environment is calculated, including: ANSYS finite element software is used to perform thermal simulation on the laser communication terminal and calculate the installation deformation caused by the space thermal environment. The Altair super engineering software is used to perform gravity simulation on the laser communication terminal and calculate the installation deformation caused by the influence of the space gravity environment.

3. The method according to claim 2, characterized in that The ANSYS finite element software is used to perform thermal simulation on the laser communication terminal to calculate the installation deformation caused by the space thermal environment, including: Multiple temperature measurement points are evenly arranged around the installation surface of the laser communication terminal; After the laser communication terminal enters orbit, the temperature data of the temperature measurement points are collected; Based on the temperature data of the temperature measuring points, the material of the installation surface and the product structure, modeling and analysis are performed in the ANSYS finite element software to calculate the installation deformation caused by the influence of the spatial thermal environment.

4. The method according to claim 2, characterized in that: The Altair super engineering software is used to perform gravity simulation on the laser communication terminal, and the installation deformation caused by the influence of the space gravity environment is calculated, including: Establish a structural model of the entire satellite assembly in the Altair Super Engineering Software; The spatial gravity changes are input into the structural model, the structural deformation is simulated, and the installation deformation amount caused by the influence of the spatial gravity environment is obtained.

5. The method according to claim 1, characterized in that The method of correcting the target star position information pointed to by the laser communication terminal through the Beidou short message information to obtain the space orbit error correction value includes: Make low-orbit satellite A carry laser communication terminal A and Beidou short message payload A, make low-orbit satellite B carry Beidou short message payload B, and take low-orbit satellite B as the target satellite; The real-time position information of the low-orbit satellite B is sent to the Beidou satellite via the Beidou short message payload B; The Beidou satellite transmits the real-time position information of the low-orbit satellite B to the Beidou short message payload A through the Beidou ground station, and calculates the space orbit error correction of the laser communication terminal A.

6. The method according to claim 5, characterized in that The method of correcting the target star position information pointed to by the laser communication terminal through the Beidou short message information to obtain the space orbit error correction value includes: Make low-orbit satellite A carry Beidou short message payload A, make low-orbit satellite B carry laser communication terminal B and Beidou short message payload B, and use low-orbit satellite A as the target satellite; The real-time position information of low-orbit satellite A is sent to the Beidou satellite via Beidou short message payload A; Beidou satellite sends the real-time position information of low-orbit satellite A to Beidou short message payload B through the Beidou ground station, and calculates the space orbit error correction of laser communication terminal B.

7. The method according to claim 1, characterized in that After comprehensively correcting the initial pointing direction of the laser communication terminal according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount, the method further includes: Based on the comprehensive corrected aiming angle, the target is quickly captured.

8. A device for quickly correcting the initial aiming error of a laser communication terminal on orbit, characterized in that: include: The initial pointing calculation module is used to calculate the initial pointing of the laser communication terminal according to the orbit and attitude information of the binary satellites; The installation deformation calculation module is used to use the finite element simulation analysis method to perform thermal simulation and gravity simulation on the laser communication terminal, and calculate the installation deformation caused by the influence of the space thermal environment and gravity environment; An installation deformation correction module is used to convert the installation deformation caused by the space thermal environment and the gravity environment into the pointing error of the laser communication terminal, and obtain the space thermal environment change correction amount and the gravity environment change correction amount; The orbit error correction module is used to correct the target satellite position information pointed by the laser communication terminal through Beidou short message information to obtain the space orbit error correction value; The comprehensive pointing correction module is used to comprehensively correct the initial pointing of the laser communication terminal according to the space thermal environment change correction amount, the gravity environment change correction amount and the space orbit error correction amount.

9. An electronic device, characterized in that: include: processor; as well as A memory arranged to store computer executable instructions which, when executed, cause the processor to perform the steps of the method as claimed in any one of claims 1 to 7.

10. A storage medium, characterized in that: include: The storage medium stores a processing program for quickly correcting the initial aiming error of the laser communication terminal on-orbit. When the processing program for quickly correcting the initial aiming error of the laser communication terminal on-orbit is executed by the processor, the method steps described in any one of claims 1-7 are implemented.

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