A method for calculating dynamic inter-satellite communication visibility based on a low-orbit mega constellation

Abstract

The application discloses a kind of based on low-orbit giant constellation dynamic inter-satellite communication visibility calculation method, comprising the following steps: obtaining the latest TLE ephemeris data of two satellites under a certain constellation, based on TLE ephemeris data and specific epoch, the spatial position of two satellites is calculated using SGP4 orbit prediction model;Then the inter-satellite line-of-sight visibility between two satellites is calculated, and the result is characterized as a Boolean quantity;Utilize the optical power budget function based on inter-satellite laser link establishment, carry out received optical power budget;The azimuth and elevation of communication antenna under satellite body coordinate system are calculated;Finally, the visibility result of two satellites is calculated, the specific communication antenna number of satellite is determined, and the constellation inter-satellite visibility matrix is established.The application discloses a kind of based on low-orbit giant constellation dynamic inter-satellite communication visibility calculation method, constellation scale and calculation speed have higher flexibility and computing performance, inter-satellite visibility calculation is more in line with actual satellite communication scene.

Description

Technical Field

[0001] This invention relates to the field of data computing, and more particularly to a method for calculating the visibility of dynamic inter-satellite communication based on a low-Earth orbit mega-constellation. Background Technology

[0002] Space-based internet can effectively address the needs of limited coverage areas and emergency communication. Currently, low-Earth orbit (LEO) satellite constellations based on laser inter-satellite communication are the main direction of space-based internet construction. LEO inter-satellite link networking faces challenges such as an explosive growth in link nodes, dynamic changes in network topology, uneven on-board load distribution, and limited on-board resources. Research on these issues requires equivalent on-orbit experimental verification. Due to the large number of satellites in mega-constellations and the high speed of LEO satellite operation, researching methods for calculating the dynamic visibility matrix of communication between mega-satellites in LEO, and characterizing the physical connectivity of satellites in space based on communication in real time, is crucial for equivalent on-orbit experimental verification of satellites.

[0003] Currently, inter-satellite visibility calculations mainly use STK (Satellite Tool Kit) to model satellite orbits and then import the generated orbit models into network simulation software. This method is limited by the computing performance of STK itself, and is greatly restricted in terms of flexibility and constellation scale. The import process requires manual operation, which is cumbersome, and real-time ephemeris calculations cannot be performed. The calculations are based only on the satellite's spatial position and do not take into account communication-related parameters. Summary of the Invention

[0004] In view of the aforementioned shortcomings of existing technologies, the technical problem to be solved by this invention is that existing inter-satellite visibility calculations are severely limited in flexibility and constellation scale, require manual operation during the import process, are cumbersome, and cannot perform real-time ephemeris calculations. They can only perform calculations based on satellite spatial positions and do not involve communication-related parameters. Therefore, this invention provides a dynamic inter-satellite communication visibility calculation method based on a low-Earth orbit mega-constellation, realizing the problems of dynamic satellite orbit models and dynamic inter-satellite visibility calculations. It offers greater flexibility and computational performance in terms of constellation scale and calculation speed. Based on the relative spatial positions of satellites, it considers issues such as optical signal attenuation in laser communication, ATP alignment efficiency, and whether the antenna azimuth and elevation angles meet the required ranges, making the inter-satellite visibility calculation more consistent with actual satellite communication scenarios.

[0005] To achieve the above objectives, this invention provides a method for calculating the visibility of dynamic inter-satellite communication based on a low-Earth orbit mega-constellation, comprising the following steps:

[0006] Obtain the latest TLE ephemeris data for two satellites under a certain constellation, and calculate the spatial positions of the two satellites based on the TLE ephemeris data and specific epochs using the SGP4 orbit prediction model;

[0007] Based on the stated spatial positions of the two satellites, calculate the inter-satellite line-of-sight visibility between the two satellites, and characterize the result using a Boolean quantity.

[0008] Based on the spatial positions of the two satellites, the received optical power budget is calculated using the optical power budget function established based on the inter-satellite laser link;

[0009] Based on the stated spatial positions of the two satellites, calculate the azimuth and elevation angles of the communication antenna in the satellite body coordinate system;

[0010] Based on the inter-satellite line-of-sight visibility, received optical power budget, and optical receiver sensitivity, the visibility results of the two satellites are calculated. The specific communication antenna numbers of the satellites are determined according to the antenna azimuth and elevation angles, and an inter-satellite visibility matrix for the constellation is established. It should be noted that one satellite is the transmitter, and the other is the receiver.

[0011] Furthermore, based on the spatial positions of the two satellites, the inter-satellite line-of-sight visibility between the two satellites is calculated, and the result is represented by a Boolean value. This specifically includes the following steps:

[0012] Based on the stated spatial positions of the two satellites, the satellite altitude above the ground, longitude and latitude of the satellite nadir point, and the coordinates of the satellites in the J2000 coordinate system are obtained in the WGS-84 coordinate system.

[0013] Based on the obtained longitude, latitude, and altitude above the ground, calculate the satellite's rectangular coordinates in the WGS-84 coordinate system;

[0014] Then, based on the xyz coordinates of the two satellites in the rectangular coordinate form of the WGS-84 coordinate system, the spatial straight-line distance between the two satellites is calculated.

[0015] Finally, based on the straight-line distance between the two satellites and their altitude above the ground, the inter-satellite line-of-sight visibility between the two satellites is calculated.

[0016] Furthermore, based on the obtained longitude, latitude, and altitude, the satellite's rectangular coordinates in the WGS-84 coordinate system are calculated using the following conversion formula:

[0017]

[0018]

[0019] Where B is the satellite latitude, L is the satellite longitude, H is the satellite altitude, and N is the normal length. The square of the eccentricity of the first ellipsoid is 0.0066943799013. The major radius of the ellipsoid is 6378.137 km.

[0020] Furthermore, based on the xyz coordinates of the two satellites in the Cartesian coordinate system of WGS-84, the spatial straight-line distance between the two satellites is calculated using the following formula:

[0021] in, Let xyz be the coordinates of satellite 1. Here are the xyz coordinates of satellite 2.

[0022] Furthermore, based on the straight-line distance between the two satellites and their altitude above the Earth, the inter-satellite line-of-sight visibility between the two satellites is calculated, as follows:

[0023]

[0024]

[0025]

[0026]

[0027] Where h1 is the altitude of satellite 1 above the ground, h2 is the altitude of satellite 2 above the ground, L is the distance between the two satellites, and R is the Earth's radius.

[0028] Furthermore, based on the stated spatial positions of the two satellites, the received optical power budget is calculated using the optical power budget function established based on the inter-satellite laser link, specifically including:

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] in, The average emitted optical power, To receive average optical power, For the efficiency of the laser emission system, For the transmit antenna gain, and beam divergence angle related, To improve the efficiency of free space transmission, and light wavelength The distance L between the two satellites in space is related to their relative position. For the efficiency of the laser receiving system, For receiving antenna gain, and light wavelength Optical aperture of the receiving system related, To improve ATP alignment and adaptation efficiency, and beam divergence angle Standard deviation of the aiming error at the transmitter Related; simplifying the above formula yields:

[0035]

[0036] In the formula, , , All are constants, so the received optical power budget can be determined. It is greatly affected by the straight-line distance L between the two satellites in space.

[0037] Furthermore, based on the spatial positions of the two satellites, the azimuth and elevation angles of the communication antenna in the satellite coordinate system are calculated, and whether the antenna azimuth and elevation angles meet the angular range is determined based on the relative positions of the satellites. This specifically includes the following steps:

[0038] Based on the spatial positions of the two satellites, the rectangular coordinates of the two satellites in the J2000 geocentric equatorial coordinate system and the angle between the satellite's current body coordinate system and the geocentric equatorial coordinate system are obtained, and the relative coordinate matrix of the second satellite based on the first satellite is calculated.

[0039] Based on the relative coordinate matrix of the two satellites in the J2000 geocentric equatorial coordinate system, a matrix transformation is performed, based on the relative coordinate matrix in the satellite body coordinate system;

[0040] The azimuth and elevation angles of the satellite transmitting antenna are calculated based on the relative coordinate matrix in the satellite body coordinate system.

[0041] Furthermore, based on the inter-satellite line-of-sight visibility, received optical power budget, and optical receiver sensitivity, the visibility results of the two satellites are calculated. The specific communication antenna numbers of the satellites are determined based on the antenna azimuth and elevation angles, and a constellation inter-satellite visibility matrix is ​​established. This process specifically includes the following steps:

[0042] The visibility of the two satellites is calculated based on the inter-satellite line-of-sight visibility, received optical power budget, and optical receiver sensitivity. The specific calculation formula is as follows:

[0043]

[0044] in, For the inter-satellite line-of-sight visibility results between Satellite 1 and Satellite 2, To receive optical power budget results, This refers to the sensitivity of the optical receiver.

[0045] Furthermore, when the visibility result is calculated to be true, the specific communication antenna number of the satellite is determined based on the antenna azimuth and elevation angles. Four antenna transceivers are installed on the satellite and placed on the four sides of a flat base. It is assumed that the initial pointing of each laser communication component is the direction of the satellite's motion, and the maximum azimuth angle that the laser communication component can rotate to is... The specific satellite communication number can then be obtained based on the azimuth angle:

[0046]

[0047] Where Az is the azimuth angle of the satellite transmitting antenna. This is half of the maximum azimuth angle that the laser communication component can rotate.

[0048] Based on the visibility results of any two satellites in this constellation, the inter-satellite communication visibility matrix is ​​finally obtained.

[0049] Technical effect

[0050] This invention provides a dynamic inter-satellite communication visibility calculation method based on a low-Earth orbit mega-constellation, which solves the problems of dynamic satellite orbit model and dynamic inter-satellite visibility calculation. The constellation size and calculation speed have higher flexibility and computational performance. Based on the relative spatial position of the satellites, it considers issues such as optical signal attenuation of laser communication, ATP alignment efficiency, and whether the antenna azimuth and elevation angles meet the range, making the inter-satellite visibility calculation more consistent with the actual satellite communication scenario.

[0051] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0052] Figure 1 This is a flowchart illustrating a preferred embodiment of the present invention of a dynamic inter-satellite communication visibility calculation method based on a low-Earth orbit mega-constellation.

[0053] Figure 2 This is a preferred embodiment of the present invention, showing the inter-satellite line-of-sight visibility satellite position relationship diagram based on a dynamic inter-satellite communication visibility calculation method for a low-Earth orbit mega-constellation. Detailed Implementation

[0054] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0055] In the following description, specific details, such as particular internal procedures and techniques, are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will appreciate that the invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of the invention with unnecessary detail.

[0056] like Figure 1 As shown, this embodiment of the invention provides a method for calculating the visibility of dynamic inter-satellite communication based on a low-Earth orbit mega-constellation, comprising the following steps:

[0057] S1: Obtain the latest TLE (Two-Line Orbital Element) ephemeris data for two satellites in a certain constellation. Based on the TLE ephemeris data and specific epochs, use the SGP4 orbit prediction model to calculate the spatial positions of the two satellites.

[0058] S2: As Figure 2 As shown, the inter-satellite line-of-sight visibility between two satellites is calculated based on the satellite's spatial position, and the result is represented by a Boolean value.

[0059] S3: Based on the spatial positions of the two satellites, and using the optical power budget function established by the inter-satellite laser link, perform the received optical power budget;

[0060] S4: Based on the satellite's spatial position, calculate the azimuth and elevation angles of the communication antenna in the satellite's coordinate system.

[0061] S5: Calculate the visibility results of the two satellites based on the inter-satellite line-of-sight visibility, optical power budget, and optical receiver sensitivity. Determine the specific communication antenna number of the satellite based on the antenna azimuth and elevation angles, and establish the constellation inter-satellite visibility matrix.

[0062] In one embodiment of the present invention, step S2 includes:

[0063] S21: Based on the spatial positions of the two satellites calculated in step S1, obtain the satellite altitudes H1 and H2 in the WGS-84 coordinate system, the longitudes L1 and L2 of the satellite nadir points, the latitudes B1 and B2, and the coordinates of the satellites in the J2000 coordinate system.

[0064] S22: Based on the latitude and longitude coordinates in step S21, calculate the satellite's rectangular coordinates in the WGS-84 coordinate system. The conversion formula from latitude and longitude coordinates to rectangular coordinates is as follows:

[0065]

[0066]

[0067] Where B is the satellite latitude, L is the satellite longitude, H is the satellite altitude, and N is the normal length. The square of the eccentricity of the first ellipsoid is 0.0066943799013. The major radius of the ellipsoid is 6378.137 km.

[0068] S23: Based on the xyz coordinates of the two satellites in the WGS-84 coordinate system rectangular coordinate form obtained in step S22, the spatial straight-line distance L between the two satellites is calculated using the following formula:

[0069] in, Let xyz be the coordinates of satellite 1. Here are the xyz coordinates of satellite 2.

[0070] S24: As Figure 2 As shown, based on the spatial straight-line distance between the two satellites in step S23 and the Earth's altitude of the two satellites in step S21, the formula for calculating the inter-satellite line-of-sight visibility between the two satellites is as follows:

[0071]

[0072]

[0073]

[0074]

[0075] Where h1 is the altitude of satellite 1 above the Earth's center, h2 is the altitude of satellite 2 above the Earth's center, L is the distance between the two satellites, and R is the Earth's radius.

[0076] In one embodiment of the present invention, step S3 establishes the optical power budget function based on the inter-satellite laser link as follows:

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] in, The average emitted optical power, To receive average optical power, For the efficiency of the laser emission system, For the transmit antenna gain, and beam divergence angle related, For free space transmission efficiency, and light wavelength The distance L between the two satellites in space is related to their relative position. For the efficiency of the laser receiving system, For receiving antenna gain, and light wavelength Optical aperture of the receiving system related, To improve ATP alignment and adaptation efficiency, and beam divergence angle Standard deviation of the aiming error at the transmitter Relevant. Simplifying the above formula yields:

[0083]

[0084] In the formula, , , All are constants, received optical power budget It is greatly affected by the straight-line distance L between the two satellites in space.

[0085] In one embodiment of the present invention, step S4 includes:

[0086] S41: Based on the rectangular coordinates of the two satellites in the J2000 geocentric equatorial coordinate system obtained in step 1, and the angle between the satellite's current body coordinate system and the geocentric equatorial coordinate system. The relative coordinate matrix of satellite 2 based on satellite 1 is as follows:

[0087]

[0088] in, The coordinates of satellite 1 in the J2000 coordinate system. The coordinates of satellite 2 in the J2000 coordinate system.

[0089] S42: Based on the J2000 geocentric equatorial coordinate system relative coordinate matrix obtained in step S41, perform the following matrix transformation to obtain the relative coordinate matrix based on the satellite body coordinate system. Transformation matrix as follows:

[0090]

[0091]

[0092] in, For the track inclination angle, Argument of latitude The right ascension of the ascending node can be obtained from the corresponding satellite TLE data.

[0093] In the satellite's body coordinate system, the origin is the satellite's center of mass. The axis lies in the orbital plane and points towards the Earth's center. The axis is located in the orbital plane and perpendicular to The axis points in the direction of the satellite's flight. The right-hand rule is satisfied.

[0094] S43: Based on the relative coordinate matrix in the satellite body coordinate system described in step S42 Satellite orientation angle and pitch angle The calculation formula is as follows:

[0095]

[0096]

[0097] The satellite laser was originally emitted along the satellite's coordinate system. Shaft. In one embodiment of the present invention, step S5 includes:

[0098] S51: Based on the inter-satellite line-of-sight visibility of the two satellites in step S2, the optical power budget in step S3, and the optical receiver sensitivity, calculate the visibility results of the two satellites, and determine the specific communication antenna number of the satellite based on the azimuth and elevation angles of the communication antennas in step S4. The calculation formula is as follows:

[0099]

[0100] in, For the inter-satellite line-of-sight visibility results between Satellite 1 and Satellite 2, To receive optical power budget results, This refers to the sensitivity of the optical receiver.

[0101] If the visibility result is true, the specific communication antenna number of the satellite is determined based on the antenna azimuth and elevation angles. Four antenna transceivers are installed on the satellite and placed on the four sides of a flat base. Assume that the initial pointing direction of each laser communication component is the direction of the satellite's motion, and the maximum azimuth angle that the laser communication component can rotate to is... The specific satellite communication number can then be obtained based on the azimuth angle:

[0102]

[0103] Where Az is the azimuth angle of the satellite transmitting antenna. This is half of the maximum azimuth angle that the laser communication component can rotate.

[0104] S52: Based on step S51, calculate the visibility results of any two satellites in this constellation, and finally obtain the inter-satellite communication visibility matrix.

[0105] The following example illustrates a dynamic inter-satellite communication visibility calculation method based on a low-Earth orbit mega-constellation provided by the present invention. In this embodiment, the visibility of two satellites, STARLINK-2331 and STARLINK-2351, will be calculated at 16:00 (UTCG) on November 28, 2022, and the specific communication antenna numbers will be determined.

[0106] 1. Obtain TLE data for the two satellites STARLINK-2331 and STARLINK-2351, and calculate the spatial positions of the two satellites using the SGP4 orbit prediction model based on the TLE ephemeris data and specific epochs.

[0107] First, obtain the TLE data for these two satellites from the website www.celestrak.com:

[0108] STARLINK-2331

[0109] 1 47875U 21021R 22288.72427687 .00001235 00000+0 10175-3 0 9999 2 47875 53.0531 82.5350 0001250 103.5218 256.5910 15.06407222 89207

[0111] STARLINK-2351

[0112] 1 47891U 21021AH 22288.72337468 .00000139 00000+0 28260-4 0 9991 2 47891 53.0553 92.5408 0001310 104.2323 255.8812 15.06391453 89173

[0114] The SGP4 orbit prediction model was used to calculate the satellite altitude, longitude and latitude of the satellite nadir point, and rectangular coordinates in the J2000 coordinate system for these two satellites at 16:00 on November 28, 2022 (UTCG).

[0115] ground clearance / km Longitude / ° Latitude / ° J2000_x / km J2000_y / km J2000_z / km STARLINK-2331 550.85 77.256 40.905 4781.68 2174.59 4504.58 STARLINK-2351 551.98 81.484 43.978 4390.17 2400.62 4779.93

[0116] Based on the obtained longitude, latitude, and altitude, calculate the satellite's rectangular coordinates in the WGS-84 coordinate system using the following conversion formula.

[0117]

[0118] Where B is the satellite latitude, L is the satellite longitude, H is the satellite altitude, and N is the normal length. The square of the eccentricity of the first ellipsoid is 0.0066943799013. The semi-major radius of the ellipsoid is 6378.137 km. The calculated satellite coordinates in the WGS-84 coordinate system are as follows:

[0119] WGS-84_x / km WGS-84_y / km WGS-84_z / km STARLINK-2331 1156.79 5114.66 4515.15 STARLINK-2351 739.55 4939.29 4789.65

[0120] Calculate the straight-line distance between the two satellites and substitute it into rectangular coordinates in the WGS-84 coordinate system:

[0121]

[0122] 2. Based on the straight-line distance L between the two satellites and their altitude above the Earth, calculate the inter-satellite line-of-sight visibility between them using the following formula:

[0123]

[0124]

[0125]

[0126]

[0127] Where h1 is the altitude of STARLINK-2331 above the Earth (550.85 km), h2 is the altitude of STARLINK-2351 above the Earth (551.98 km), and R is the Earth's radius (6371 km). Substituting these values ​​into the above formula, we get:

[0128] =46.05-4.38>0

[0129] This means that the line-of-sight between the two satellites is visible.

[0130] 3. Based on the spatial positions of the two satellites, calculate the optical power budget for the inter-satellite laser link using the optical power budget function established based on the inter-satellite laser link.

[0131]

[0132]

[0133] 4. Based on the spatial positions of the two satellites, calculate the azimuth and elevation angles of the communication antenna in the satellite coordinate system.

[0134]

[0135] in, The coordinates of satellite 1 in the J2000 coordinate system. The coordinates of satellite 2 in the J2000 coordinate system

[0136]

[0137] Relative coordinate matrix based on satellite body coordinate system Transformation matrix as follows:

[0138]

[0139]

[0140] in, For the track inclination angle, Argument of latitude The right ascension of the ascending node can be obtained from the TLE data of STARLINK-2331.

[0141]

[0142]

[0143] Relative coordinate matrix based on satellite body coordinate system Satellite orientation angle and pitch angle The calculation formula is as follows:

[0144]

[0145]

[0146] 5. Based on the inter-satellite line-of-sight visibility of the two satellites in step 2, the optical power budget in step 3, and the optical receiver sensitivity, calculate the visibility results of the two satellites, and determine the specific communication antenna number of the satellite based on the azimuth and elevation angles of the communication antennas in step 4. The calculation formula is as follows:

[0147]

[0148] in, For the inter-satellite line-of-sight visibility results between Satellite 1 and Satellite 2, To receive optical power budget results, This refers to the sensitivity of the optical receiver.

[0149]

[0150] When the visibility result is calculated to be true, the specific communication antenna number of the satellite is determined based on the antenna azimuth and elevation angles. Specifically, four antenna transceivers are installed on the satellite and placed on the four sides of a flat base. It is assumed that the initial pointing direction of each laser communication component is the direction of the satellite's motion, and the maximum azimuth angle that the laser communication component can rotate to is... The specific satellite communication number can then be obtained based on the azimuth angle:

[0151]

[0152] in, The azimuth angle of the satellite transmitting antenna. This is half of the maximum azimuth angle that the laser communication component can rotate.

[0153] Assumption In this case, STARLINK-2331 and STARLINK-2351 can achieve satellite communication, with STARLINK-2331 antenna numbered 4. 45° is the critical value for omnidirectional coverage without overlapping antenna coverage areas; other angles may be assumed in other embodiments of the present invention.

[0154] Repeat step 4 and modify. , , The three parameters are the TLE data for STARLINK-2351. The azimuth angle of the communication antenna for STARLINK-2351 and STARLINK-2331 satellite communication is 103.38°. Assuming... Therefore, the STARLINK-2351 antenna is number 2.

[0155] Repeating the above steps allows for the calculation of visibility between any two satellites, ultimately yielding the inter-satellite communication visibility matrix. This invention provides a dynamic inter-satellite communication visibility calculation method based on a low-Earth orbit (LEO) mega-constellation, solving problems in traditional satellite network simulation technologies such as discontinuous dynamic constellation construction, high computational time overhead, and satellite constellation size limited by constellation modeling software. It provides real-time and reliable data support for building satellite network simulation systems. The mathematical model used in this invention has a computational speed dependent on host configuration, unaffected by software limitations, and can be modified according to business scenarios, even adding more consideration formulas, offering high flexibility. Compared to existing technologies that typically model and simulate based on single satellite objects, this invention's dynamic inter-satellite communication visibility calculation method based on a LEO mega-constellation can provide the connectivity relationships between all satellites within the constellation, better meeting the needs of equivalent on-orbit experiments.

[0156] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for calculating the visibility of dynamic inter-satellite communication based on a low-Earth orbit mega-constellation, characterized in that, Includes the following steps: Obtain the latest TLE ephemeris data for two satellites under a certain constellation, and calculate the spatial positions of the two satellites based on the TLE ephemeris data and specific epochs using the SGP4 orbit prediction model; Based on the stated spatial positions of the two satellites, calculate the inter-satellite line-of-sight visibility between the two satellites, and characterize the result using a Boolean quantity. Based on the spatial positions of the two satellites, the received optical power budget is calculated using the optical power budget function established based on the inter-satellite laser link; Based on the stated spatial positions of the two satellites, calculate the azimuth and elevation angles of the communication antenna in the satellite body coordinate system; Based on the inter-satellite line-of-sight visibility, received optical power budget, and optical receiver sensitivity, the visibility results of the two satellites are calculated. Based on the antenna azimuth and elevation angles, the specific communication antenna numbers of the satellites are determined, and an inter-satellite visibility matrix for the constellation is established.

2. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 1, characterized in that, Based on the stated spatial positions of the two satellites, the inter-satellite line-of-sight visibility between them is calculated and represented by a Boolean value. The specific steps include: Based on the stated spatial positions of the two satellites, the satellite altitude above the ground, longitude and latitude of the satellite nadir point, and the coordinates of the satellites in the J2000 coordinate system are obtained in the WGS-84 coordinate system. Based on the obtained longitude, latitude, and altitude above the ground, calculate the satellite's rectangular coordinates in the WGS-84 coordinate system; Then, based on the xyz coordinates of the two satellites in the rectangular coordinate form of the WGS-84 coordinate system, the spatial straight-line distance between the two satellites is calculated. Finally, based on the straight-line distance between the two satellites and their altitude above the ground, the inter-satellite line-of-sight visibility between the two satellites is calculated.

3. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 2, characterized in that, Based on the obtained longitude, latitude, and altitude, the satellite's rectangular coordinates in the WGS-84 coordinate system are calculated using the following conversion formula: Where B is the satellite latitude, L is the satellite longitude, H is the satellite altitude, and N is the normal length. The square of the eccentricity of the first ellipsoid is 0.0066943799013. The major radius of the ellipsoid is 6378.137 km.

4. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 3, characterized in that, Based on the xyz coordinates of the two satellites in Cartesian coordinates of the WGS-84 coordinate system, the spatial straight-line distance between the two satellites is calculated using the following formula: in, The coordinates of satellite 1 in the WGS-84 coordinate system. These are the coordinates of satellite 2 in the WGS-84 coordinate system.

5. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 4, characterized in that, Based on the straight-line distance between the two satellites and their altitude above the Earth, the inter-satellite line-of-sight visibility between the two satellites is calculated as follows: Where h1 is the altitude of satellite 1 above the ground, h2 is the altitude of satellite 2 above the ground, L is the distance between the two satellites, and R is the Earth's radius.

6. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 5, characterized in that, Based on the stated spatial positions of the two satellites, the received optical power budget is calculated using the optical power budget function established based on the inter-satellite laser link, specifically including: in, The average emitted optical power, To receive average optical power, For the efficiency of the laser emission system, For the transmit antenna gain, and beam divergence angle related, To improve the efficiency of free space transmission, and light wavelength The distance L between the two satellites in space is related to their relative position. For the efficiency of the laser receiving system, For receiving antenna gain, and light wavelength Optical aperture of the receiving system related, To improve ATP alignment and adaptation efficiency, and beam divergence angle Standard deviation of the aiming error at the transmitter Related; simplifying the above formula yields: In the formula, , , All are constants.

7. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 1, characterized in that, Based on the stated spatial positions of the two satellites, the azimuth and elevation angles of the communication antenna in the satellite coordinate system are calculated, specifically including the following steps: Based on the spatial positions of the two satellites, the rectangular coordinates of the two satellites in the J2000 geocentric equatorial coordinate system and the angle between the satellite's current body coordinate system and the geocentric equatorial coordinate system are obtained, and the relative coordinate matrix of the second satellite based on the first satellite is calculated. Based on the relative coordinate matrix of the two satellites in the J2000 geocentric equatorial coordinate system, matrix transformation is performed to calculate the relative coordinate matrix based on the satellite body coordinate system. The azimuth and elevation angles of the satellite transmitting antenna are calculated based on the relative coordinate matrix in the satellite body coordinate system.

8. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 1, characterized in that, Based on the inter-satellite line-of-sight visibility, received optical power budget, and optical receiver sensitivity, the visibility results of the two satellites are calculated. The specific communication antenna numbers of the satellites are determined based on the antenna azimuth and elevation angles, and a constellation inter-satellite visibility matrix is ​​established. This process specifically includes the following steps: The visibility of the two satellites is calculated based on the inter-satellite line-of-sight visibility, received optical power budget, and optical receiver sensitivity. The specific calculation formula is as follows: in, For the inter-satellite line-of-sight visibility results between Satellite 1 and Satellite 2, To receive optical power budget results, This refers to the sensitivity of the optical receiver.

9. The method for calculating dynamic inter-satellite communication visibility based on a low-Earth orbit mega-constellation as described in claim 8, characterized in that, When the visibility result is calculated to be true, the specific communication antenna number of the satellite is determined based on the antenna azimuth and elevation angles. Specifically, four antenna transceivers are installed on the satellite and placed on the four sides of a flat base. It is assumed that the initial pointing direction of each laser communication component is the direction of the satellite's motion, and the maximum azimuth angle that the laser communication component can rotate to is... The specific satellite communication number can then be obtained based on the azimuth angle: Where Az is the azimuth angle of the satellite transmitting antenna. This is half of the maximum azimuth angle that the laser communication component can rotate. Based on the visibility results of any two satellites in this constellation, the inter-satellite communication visibility matrix is ​​finally obtained.

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