A Low Earth Orbit Satellite Link Simulation Method and System

Abstract

The present invention provides a method and system for simulating a low-earth orbit satellite link. The method includes: constructing a spherical frustum simulation constraint space for a low-earth orbit satellite channel scenario, establishing the space-time state information of the low-earth orbit satellite and the space-time state information of the receiving end in the spherical frustum simulation constraint space, constructing a multi-satellite multi-user simulation time sequence grid, establishing a link simulation discrete time slice based on a variable time granularity, performing simulation on a single link in sequence according to the simulation time serial number in the discrete time slice, performing simulation on multiple links according to the simulation time value, and converting the simulation results into a low-earth orbit satellite simulation video. The present invention can simulate the communication scenarios of multiple satellites and multiple receiving ends, ensuring the integrity of the low-earth orbit satellite simulation and realizing the visualization of simulation data.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite communication simulation, and particularly to a method and system for simulating a low-earth orbit satellite link. Background Art

[0002] Large-scale low-earth orbit satellite networks have characteristics such as high-speed movement, short coverage periods, high connection density, and hopping beam communication. These characteristics make it difficult to ensure the stability and real-time performance of user communication services during access and handover processes, and their communication schemes will become more complex. In a low-earth orbit satellite internet system, the service time of a single satellite is often shorter than the service time required by users. Therefore, users will select satellites multiple times or re-select satellites during communication. At the same time, in order to improve the resource utilization efficiency of the satellite system, a hopping beam communication method needs to be adopted to cover multiple beam coverage areas in a time-division or frequency-division manner. And the access devices of low-earth orbit satellites need to consider their high-speed mobility. Devices such as high-speed trains and cars are all in a state of high-speed movement. Therefore, the low-earth orbit satellite communication channel needs to have strong spatial correlation. However, existing low-earth orbit satellite link simulation methods mainly consider the link performance simulation of a single link. At the same time, the simulation results obtained by existing low-earth orbit satellite link simulation methods have low authenticity and are difficult to meet the visualization requirements of low-earth orbit satellite link simulation results. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a method and system for simulating a low-earth orbit satellite link to solve the problem that existing low-earth orbit satellite link simulation methods only simulate a single link and cannot visualize the simulation results of low-earth orbit satellites.

[0004] One aspect of the present invention provides a method for simulating a low-earth orbit satellite link. The method is carried out on a software simulation platform and includes the following steps:

[0005] Set up a simulation observation area, establish an earth spherical cap surface within the simulation observation area, establish a station-centered coordinate system with the center of the simulation observation area as the origin, and the vertex of the earth spherical cap surface coincides with the origin; obtain the orbital information of multiple low-earth orbit satellites to be simulated, construct a ray with the origin as an end point, rotate around the Z-axis of the station-centered coordinate system according to the minimum access elevation angle of the coverage center point, and cut the sphere where the highest low-earth orbit satellite is located to obtain a constellation highest orbit spherical cap surface. Take the earth spherical cap surface as the bottom and the constellation highest orbit spherical cap surface as the top to construct a spherical frustum simulation constraint space;

[0006] Obtain the motion trajectories of each low-earth orbit satellite in the spherical frustum simulation constraint space in the Earth-centered Earth-fixed coordinate system, and transform the motion trajectories into the station-centered coordinate system; calculate the intersection trajectories of each motion trajectory with the spherical frustum simulation constraint space to obtain the number of target low-earth orbit satellites providing services for the receiving end, and convert the intersection trajectories into the geodetic coordinate system to obtain the space-time state information of each target low-earth orbit satellite; obtain the number of receiving ends and the motion trajectories of each receiving end to obtain the space-time state information of each receiving end.

[0007] According to the space-time state information of each low-earth orbit satellite and the space-time state information of each receiving end, determine the time-domain order of the links established between each target low-earth orbit satellite and each receiving end, and mark the simulation sequence numbers for each link to construct a multi-star multi-user simulation time sequence grid; divide the overpass time of each target low-earth orbit satellite into multiple time slices, calculate the time granularity of each time slice, discretize the space-time states and link parameters of the corresponding target low-earth orbit satellite and each receiving end based on the time granularity, simulate the link states within each time slice according to a preset model, and construct a discrete space-time link information matrix recording the space-time states and link states between each target low-earth orbit satellite and each receiving end.

[0008] Among them, determine the time slices in which each link participates in the simulation according to the connection time domain of each target low-earth orbit satellite and the receiving end, and sequentially simulate the links that need to be simulated in each time slice. When the simulation is a single-link simulation, each link is sequentially simulated according to the simulation sequence number in the multi-star multi-user simulation time sequence grid; when the simulation is a multi-link simulation, divide the simulation sequence number of each link by the number of receiving ends and round down to obtain the corresponding simulation time value, and simulate in ascending order according to the simulation time value. For links with the same simulation time value, perform parallel simulation and output the simulation results.

[0009] In some embodiments, the method further includes:

[0010] Obtain the discrete space-time link information matrix recording the space-time states and link states between each target low-earth orbit satellite and each receiving end, and convert the data corresponding to each time slice into single-frame image information.

[0011] Perform visual demonstration on the image information corresponding to consecutive time slices.

[0012] In some embodiments, the method further includes:

[0013] Encapsulate the single-frame image information corresponding to each time slice into a video frame data packet, and add frame header information and frame tail information.

[0014] During the transmission of the video frame data packet, when an interruption occurs, the data in the last data sending cycle is parsed, and if the frame end information is matched, the frame end information is combined with the data that has been cached into a video frame data packet; otherwise, the data in the last data sending cycle is placed in the cache area and waits for subsequent data.

[0015] In some embodiments, the link state in each time slice is simulated according to a preset model, and a discrete space-time link information matrix is ​​constructed to record the space-time state and link state between each target low-orbit satellite and each receiving end, including:

[0016] For a single time slice, calculating a time-varying elevation angle between a target low-orbit satellite and a receiving end according to the low-orbit satellite space-time state information and the receiving end space-time state information;

[0017] For a single time slice, a signal-to-noise ratio heat map of different beam positions of the simulated observation area when the target low-orbit satellite passes over is calculated according to the link transmission configuration information, the simulated observation area, the space-time state information of the low-orbit satellite, antenna parameters, multi-color multiplexing parameters, and beam hopping parameters; and a signal-to-noise ratio of the receiving end when the target low-orbit satellite communicates is calculated according to the space-time state information of the receiving end;

[0018] For a single time slice, multiple channel fading models are obtained, and channel information when the target low-orbit satellite communicates with the receiving end is generated according to the space-time state information of the receiving end and the geographical environment of the receiving end;

[0019] The discrete space-time link information matrix is ​​obtained by combining the low-orbit satellite space-time state information, the receiving end space-time state information, the signal-to-noise ratio, the time-varying elevation angle and the channel information in each time slice.

[0020] In some embodiments, the calculation formula of the simulation timing number is:

[0021] SEQ l,m =(m-1)L+l;

[0022] Among them, SEQ l,m represents the simulation sequence number, m represents the mth target low-orbit satellite, l represents the lth receiving end, and L represents the total number of receiving ends.

[0023] In some embodiments, determining the time slices for each link to participate in the simulation according to the connection time domain between each target low-orbit satellite and the receiving end includes:

[0024] According to the discrete space-time link information matrix, finding the connection time domain of each target low-orbit satellite operating in the spherical cone simulation constraint space;

[0025] Determine whether each time slice belongs to the connection time domain of each target low-earth orbit satellite. For each time slice, mark the target low-earth orbit satellite corresponding to its connection time domain as 1, and mark the remaining target low-earth orbit satellites as 0;

[0026] Within each time slice, only simulate the target low-earth orbit satellites marked as 1.

[0027] In some embodiments, the link parameters include code rate, channel coding mode, modulation mode, subcarrier spacing, bandwidth, and electromagnetic frequency.

[0028] In some embodiments, the method further includes: evaluating the communication status performance of each target low-earth orbit satellite and each receiving end according to the discrete space-time link information matrix obtained by simulation, and generating an evaluation report.

[0029] The beneficial effects of the present invention are at least:

[0030] The low-earth orbit satellite link simulation method and system of the present invention constructs a spherical frustum simulation constraint space for the low-earth orbit satellite channel scenario. According to the space-time state information of each low-earth orbit satellite and the space-time state information of each receiving end in the spherical frustum simulation constraint space, a multi-star multi-user simulation time sequence grid within the spherical frustum simulation constraint space is constructed. A link simulation discrete time slice based on variable time granularity is established, and the link state within each time slice is simulated to obtain a discrete space-time link information matrix. According to the connection time domain of each target low-earth orbit satellite and each receiving end, the time slice in which each link participates in the simulation is determined, and each link simulates the target low-earth orbit satellite under the corresponding time slice. Single-link simulation and multi-link simulation methods are set up to simulate the low-earth orbit satellite communication scenario of multiple low-earth orbit satellites and multiple receiving ends, ensuring the integrity of the low-earth orbit satellite link communication scenario simulation.

[0031] Furthermore, divide the overpass time of each target low-earth orbit satellite into multiple time slices and calculate the time granularity. During the simulation process, the efficiency and accuracy of the link simulation can be adjusted by adjusting the time granularity and the simulation communication duration of the time slice, improving the accuracy of the simulation.

[0032] Furthermore, convert the simulation result after simulation into a low-earth orbit satellite simulation video, realizing the visualization of the low-earth orbit satellite simulation result data.

[0033] Furthermore, analyze the discrete space-time link information matrix and the low-earth orbit satellite simulation video obtained after simulation to obtain the transmission performance of each link and timely adjust the parameters of the link with poor transmission performance to avoid error codes during the simulation process, improving the credibility of the simulation.

[0034] Furthermore, a multi-level parallel pipeline simulation mechanism including link simulation, link demonstration, and data storage is designed, which improves the simulation efficiency of low-earth orbit satellite link simulation.

[0035] Additional advantages, objects, and features of the present invention will be partly described below, and will partly become apparent to those of ordinary skill in the art after studying the following parts, or may be learned from the practice of the present invention. The objects and other advantages of the present invention can be realized and obtained by the structure specifically pointed out in the specification and the drawings.

[0036] Those skilled in the art will understand that the objects and advantages that can be achieved by the present invention are not limited to the above specifically described, and the above and other objects that the present invention can achieve will be more clearly understood according to the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not constitute a limitation to the present invention. In the drawings:

[0038] Figure 1 is the overall flowchart of the low-earth orbit satellite link simulation method according to an embodiment of the present invention.

[0039] Figure 2 is the low-earth orbit satellite link simulation method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To make the objects, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with the embodiments and the drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0041] Herein, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, and other details less related to the present invention are omitted.

[0042] It should be emphasized that the term "including / comprising" when used herein refers to the presence of features, elements, steps, or components, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0043] Herein, it should also be noted that if not specifically stated, the term "connection" in this article can not only refer to a direct connection, but also represent an indirect connection with an intermediate.

[0044] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0045] The low-earth orbit satellite internet has been incorporated as one of the important visions into the ongoing pre-research of 6G (Sixth Generation). With the large-scale commercialization of the 5G mobile communication system, it provides high-speed, stable, and reliable services for people's daily communication. However, due to the limitations of traditional terrestrial networks, it is unable to solve the problem of high-speed data communication in maritime, aviation, and other areas not covered by terrestrial networks. Satellite communication has become a highly concerned communication method to solve this problem. Due to its wide coverage and large communication capacity, etc., it has become an important part of the 6G communication system, providing global seamless access capabilities. The International Organization for Standardization 3GPP has focused on studying the role and impact of satellite communication on the 6G mobile network in the relevant standards of non-terrestrial communication networks. Currently, the 6G mobile communication technology integrating satellite communication is being widely studied and explored. The 6G mobile communication technology integrating satellite communication will provide a forward-looking foundation for new information service fields such as virtual reality, smart cities, and unattended operations. However, the existing low-earth orbit satellite link simulation technology can only perform single-link low-earth orbit satellite simulation with low simulation accuracy and cannot meet the visualization requirements of the simulation process. Therefore, the present invention provides a low-earth orbit satellite link simulation method and system to solve the problem that the existing low-earth orbit satellite simulation method cannot simulate the low-earth orbit satellite link in a multi-satellite and multi-receiver communication scenario.

[0046] One aspect of the present invention provides a low-earth orbit satellite link simulation method, which is carried out on a software simulation platform, such as Figure 2 as shown, the method includes steps S101 to S103:

[0047] S101: Set the simulation observation area, establish an earth spherical cap surface within the simulation observation area, establish a station-centered coordinate system with the center of the simulation observation area as the origin, and the vertex of the earth spherical cap surface coincides with the origin; obtain the orbital information of multiple low-earth orbit satellites to be simulated, construct rays with the origin as the endpoint, and rotate and cut the sphere where the highest low-earth orbit satellite is located around the Z-axis of the station-centered coordinate system according to the minimum access elevation angle of the coverage center point to obtain the constellation's highest orbit spherical cap surface, and construct a spherical frustum simulation constraint space with the earth spherical cap surface as the bottom and the constellation's highest orbit spherical cap surface as the top.

[0048] S102: Obtain the motion trajectories of each low-earth orbit satellite in the spherical frustum simulation constraint space in the Earth-centered Earth-fixed coordinate system, and transform the motion trajectories into the station-centered coordinate system; calculate the intersection trajectories of each motion trajectory with the spherical frustum simulation constraint space to obtain the number of target low-earth orbit satellites providing services for the receiving end, convert the intersection trajectories into the geodetic coordinate system to obtain the low-earth orbit satellite spatio-temporal state information corresponding to each target low-earth orbit satellite; obtain the number of receiving ends and the motion trajectories of each receiving end to obtain the spatio-temporal state information of each receiving end.

[0049] S103: According to the spatio-temporal state information of each low-earth orbit satellite and the spatio-temporal state information of each receiving end, determine the time-domain order of the links constructed between each target low-earth orbit satellite and each receiving end, and mark the simulation sequence numbers for each link to construct a multi-star multi-user simulation time sequence grid; divide the overpass time of each target low-earth orbit satellite into multiple time slices, calculate the time granularity of each time slice, perform discrete operations on the spatio-temporal states and link parameters of the corresponding target low-earth orbit satellite and each receiving end based on the time granularity, simulate the link states within each time slice according to a preset model, and construct a discrete spatio-temporal link information matrix recording the spatio-temporal states and link states between each target low-earth orbit satellite and each receiving end.

[0050] S104: Among them, determine the time slices in which each link participates in the simulation according to the connection time domain of each target low-earth orbit satellite and the receiving end, and sequentially simulate the links that need to be simulated in each time slice. When the simulation is a single-link simulation, each link is sequentially simulated according to the simulation sequence number in the multi-star multi-user simulation time sequence grid; when the simulation is a multi-link simulation, divide the simulation sequence number of each link by the number of receiving ends and round down to obtain the corresponding simulation time value, and simulate according to the ascending order of the simulation time values. For links with the same simulation time value, perform parallel simulation and output the simulation results.

[0051] In step S101, there is a global map on the software simulation platform. Select a simulation observation area on the global map and establish a station-centered coordinate system with the center of the simulation observation area as the origin. The earth's spherical crown surface, the number of low-earth orbit satellites, the number of receiving ends, the simulation observation area, and the minimum access elevation angle of the center point of the simulation observation area are all arbitrarily selected and set on the software simulation platform as needed. Construct a ray with the origin of the station-centered coordinate system as the endpoint, and the angle between the ray and the ground is the minimum access elevation angle of the center point of the simulation observation area. Rotate the ray around the Z-axis of the station-centered coordinate system to be tangent to the sphere with a radius of R e +h nmax of the sphere, where h nmaxTo obtain the highest satellite altitude among the ephemerides of N satellites through the ephemeris calculation module, the resulting spherical cap surface is the highest orbital surface of the constellation, that is, the trajectories of the satellites that can provide communication support for the receiving end will not exceed this spherical cap surface in the simulation. Among them, the N satellites are set by the user according to the simulation requirements, and the receiving end is mobile. Constructing the spherical frustum simulation constraint space is to construct a simulation space for low-earth orbit satellites, and at the same time calculate the motion trajectories of low-earth orbit satellites according to the two-line orbital data TLE file input by the software simulation platform.

[0052] In some embodiments, in some embodiments, the X-axis of the topocentric coordinate system enu points to the due east, the Y enu points to the due north, and the Z enu points to the direction perpendicular to the ground upward. The radius of the earth's spherical cap surface is R e , its bottom is a circle with a radius of R TN , the height of the spherical cap is H, the vertex of the spherical cap is the origin of the topocentric coordinates, and the earth's spherical cap surface satisfies in the topocentric coordinate system:

[0053]

[0054]

[0055] Among them, x enu-tn represents the coordinate of the earth's spherical cap surface on the X-axis of the topocentric coordinate system, y enu-tn represents the coordinate of the earth's spherical cap surface on the Y-axis of the topocentric coordinate system, and z enu-tn represents the coordinate of the earth's spherical cap surface on the Z-axis of the topocentric coordinate system.

[0056] In step S102, the intersecting trajectory is converted into the geodetic coordinate system to obtain the motion trajectory of the target low-earth orbit satellite and take the derivative to obtain the motion speed of each target low-earth orbit satellite. Then, combined with the time domain of the motion of each target low-earth orbit satellite in the spherical frustum simulation constraint space, the space-time state information of the low-earth orbit satellite is obtained. According to the number of receiving ends and the motion trajectories of each receiving end, calculate the motion speed of each receiving end and the time domain of the motion of each receiving end in the spherical frustum simulation constraint space to obtain the space-time state information of each receiving end, and establish a link connection between each receiving end and each target low-earth orbit satellite in the geodetic coordinate system.

[0057] In some embodiments, according to the two-line orbit data TLE file input by the software simulation platform, the motion trajectory of each low-orbit satellite is generated in the earth-centered earth-fixed coordinate system, the motion trajectory of each low-orbit satellite is converted to the station-centered coordinate system to obtain the intersection trajectory of the motion trajectory and the simulation constraint space, the target low-orbit satellite participating in the simulation is obtained, and the intersection trajectory is converted to the longitude and latitude high coordinate system to establish a link connection between the participating target low-orbit satellite and the receiving end. Among them, the two-line orbit data TLE file includes: orbit inclination, ascending node ecliptic longitude, eccentricity, perihelion argument, semi-major axis, perihelion passing time.

[0058] In some embodiments, the motion trajectory of each satellite in the Earth-centered Earth-fixed coordinate system is represented by tle s-n-ecef (t),t∈T p , T p is the input satellite simulation survey time range, and the motion trajectory in the station center coordinate system is expressed as tle s-n-enu (t),t∈T p , then the intersection trajectory calculation formula is:

[0059] t s-n-enu (t) = tle s-n-enu (t)∩SCT constrain , t∈T p ;

[0060] Among them, t s-n-enu (t) represents the intersection trajectory, SCT constrain represents the spherical cone simulation constraint space. If t s-n-enu (t) = 0, it means that the nth satellite cannot provide service to the receiving end. Get the number of target low-orbit satellites that can provide services to the receiving end and the intersection trajectory t' of the target low-orbit satellites providing services and the spherical cone simulation constraint space s-m-enu (t), t∈T s,m , T s,m The time domain of the target low-orbit satellite moving in the spherical cone simulation constraint space. s-m-enu (t), t∈T s,m Transform to the longitude and latitude coordinate system to obtain the motion trajectory of the target low-orbit satellite t s-m-lla (t)=(u lon (t),v lat (t),w alt (t)), where u lon is longitude, v lat is latitude, w alt is the altitude, through t s-m-lla (t) The derivative is used to obtain the target low-orbit satellite motion speed V s-m (t), combined with T s,m, construct the spatio-temporal state information of the low-earth orbit satellite, INFO s-m (t s-m-lla (t), v s-m (t), T s,m ). The software simulation platform inputs the information of the ground receiving end, including the number L of receiving ends and the movement trajectory t UE-l-lla (t) of the receiving ends, calculates the movement speed v UE-l (t) of the receiving ends and the time domain T during which the receiving ends move within the constrained space ue,l , and constructs the spatio-temporal state information INFO UE-l (t UE-l-lla (t), v UE-l (t), T ue,l ) of L ground mobile receiving ends

[0061] In step S103, according to the link connection information between each receiving end and each target low-earth orbit satellite, and according to the time domain T l,m in the spherical frustum simulation constrained space of each link, construct a multi-star multi-user simulation timing grid GRID with a size of L rows and M columns corresponding to the ground mobile receiving ends and the target low-earth orbit satellites SEQ-L×M , and perform simulation timing allocation for each link according to the time domain order of each link. L represents L receiving ends, and M represents M target low-earth orbit satellites. Record the information matrix and simulation sequence number SEQ of each link in the multi-star multi-user simulation timing grid l,m . Divide the over-the-top time of the target low-earth orbit satellite into multiple time slices, calculate the time granularity, and perform discretization operations on the spatio-temporal states and link parameters of each target low-earth orbit satellite and each receiving end, that is, regard a time slice as a fixed time value to ensure that the spatial states and link parameters of the target low-earth orbit satellite and the receiving end do not change within this time slice for the convenience of simulation. Simulate the link states within each time slice according to a preset model to obtain a discrete spatio-temporal link information matrix, where the preset model is a channel fading model preset by the software simulation platform under multiple geographical environments

[0062] In some embodiments, simulate the link states within each time slice according to a preset model, and construct a discrete spatio-temporal link information matrix recording the spatio-temporal states and link states between each target low-earth orbit satellite and each receiving end, including steps S201 to S204:

[0063] S201: For a single time slice, calculate the time-varying elevation angle between the low-earth orbit satellite and the receiving end according to the spatio-temporal state information of the low-earth orbit satellite and the spatio-temporal state information of the receiving end

[0064] S202: For a single time slice, a heat map of the signal-to-noise ratio for different beam positions in the simulated observation area when the target low-orbit satellite passes overhead is calculated based on the link transmission configuration information, the simulated observation area, the space-time status information of the low-orbit satellite, the antenna parameters, the multi-color multiplexing parameters, and the beam-hopping parameters. The signal-to-noise ratio of the receiving end when the target low-orbit satellite communicates is calculated based on the space-time status information of the receiving end.

[0065] S203: For a single time slice, multiple channel fading models are obtained, and channel information when the target low-orbit satellite communicates with the receiving end is generated according to the space-time state information of the receiving end and the geographical environment of the receiving end.

[0066] S204: The space-time state information of the low-orbit satellite, the space-time state information of the receiving end, the signal-to-noise ratio, the time-varying elevation angle and the channel information in each time slice are combined to obtain a discrete space-time link information matrix.

[0067] In step S201, according to the space-time state information of the low-orbit satellite and the space-time state information of the receiving end, the simulation time of the target low-orbit satellite and the receiving end is unified to calculate T l,m =T ue,l ∩T s,m , where T l,m is the time domain in which the mth satellite and the lth receiver can establish a link connection in the spherical cone simulation constraint space. s-m-lla (t) and t UE-l-lla (t) Calculate the time-varying elevation angle α of satellite m relative to the receiver l l,m (t).

[0068] In step S202, the multi-beam pattern of the phased array of the low-orbit satellite is calculated according to the range of the simulated observation area, the space-time state information of the low-orbit satellite, the antenna parameters, the multi-color multiplexing parameters, the beam hopping parameters and the link transmission configuration information, and the SINR heat map of the signal-to-interference-to-noise ratio of different beam positions in the selected simulated observation area during the m-th satellite passing overhead is calculated. m Extract T from the space-time state information of the receiving end UE-l-lla , calculate the SINR of the receiver l when communicating with the target low-orbit satellite m l,m (t).

[0069] In step S203, the software simulation platform sets up channel fading modeling CH under various geographical environments, extracts t UE-l-lla (t), according to the longitude and latitude of the earth, the geographical environment of the receiving end is matched, and the channel information CH matching when the target low-orbit satellite m communicates with the receiving end l is generated. l,m (t).

[0070] In step S204, the target low-orbit satellite trajectory t s-m-lla(t), target low-orbit satellite motion speed v s-m (t), receiving end motion trajectory t UE-l-lla (t), receiving end movement speed v UE-l (t), the elevation angle α of the target low-orbit satellite m relative to the receiving end l l,m (t), the time domain T in which the mth target low-orbit satellite and the lth receiving end can establish a link connection in the spherical cone simulation constraint space l,m 、Signal to Interference and Noise Ratio Data Array SINR l,m (t), channel information CH l,m (t) is combined to obtain the low-orbit satellite space-time link information matrix of the receiving end l and the satellite m. The low-orbit satellite space-time link information matrix can be expressed as:

[0071] INFO l,m (t s-m-lla (t),v s-m (t),t UE-l-lla (t),v UE-l (t),T l,m ,α l,m (t),SIN R l ,m (t),CH l,m (t));

[0072] In some embodiments, the link parameters include code rate, channel coding method, modulation method, subcarrier spacing, frequency bandwidth and electromagnetic frequency.

[0073] In some other embodiments, the time granularity calculation formula is:

[0074]

[0075] Among them, t m,end Indicates the target low-orbit satellite's passing time, t m,start Indicates the start time of the target low-orbit satellite passing overhead, k indicates the kth time slice, and G indicates the time granularity.

[0076] In step S104, when performing single-link simulation, the time slices are simulated in ascending order of the sequence number during simulation; when performing multi-link simulation, the simulation time value of each link is calculated, and the simulations are performed in ascending order of the link simulation time values; if the link simulation time values are the same, after finding the links with the same simulation time value, within each time slice, the spatio-temporal states and link parameter information A of the target low-earth orbit satellite and each receiving end in this time slice are divided into a1, a2......aN parts. After the first link simulates part a1, the second link simulates part a1. When all the links with the same simulation time value have simulated part a1, the links with the same simulation time value then simulate part a2 until A is completely simulated. Since discrete-time operations are performed on the spatio-temporal states and link parameters of the target low-earth orbit satellite and each receiving end within each time slice, that is, the states and information of the target low-earth orbit satellite and the links within each time slice will not change, the links with the same simulation time value can be regarded as parallel simulations.

[0077] In some embodiments, the calculation formula for the sequence number during simulation is:

[0078] SEQ l,m =(m - 1)L + l;

[0079] where SEQ l,m represents the sequence number during simulation, m represents the m-th target low-earth orbit satellite, l represents the l-th receiving end, and L represents the total number of receiving ends.

[0080] In some other embodiments, the calculation formula for the simulation time value is:

[0081]

[0082] where Z represents the simulation time value, SEQ l,m represents the sequence number during simulation of each link, L represents the total number of receiving ends, represents rounding down.

[0083] In some embodiments, determining the time slices participated in the simulation by each link according to the connection time domain between each target low-earth orbit satellite and the receiving end includes steps S301 to S303:

[0084] S301: According to the discrete spatio-temporal link information matrix, find the connection time domain of each target low-earth orbit satellite running within the spherical frustum simulation constraint space.

[0085] S302: Determine whether each time slice belongs to the connection time domain of each target low-earth orbit satellite. For each time slice, mark the target low-earth orbit satellite corresponding to its belonging connection time domain as 1, and mark the remaining target low-earth orbit satellites as 0.

[0086] S303: In each time slice, only simulate the target low-earth orbit satellites marked as 1.

[0087] In step S301, the time domain in which the target low-earth orbit satellites and the receiving end can establish a link connection in the spherical frustum simulation constraint space is connected. The discrete space-time link information matrix records information including: the space-time state and link state between each target low-earth orbit satellite and each receiving end, that is, the time domain of the movement of each target low-earth orbit satellite and each receiving end, as well as the connection time domain and connection state between the receiving end and the target low-earth orbit satellite.

[0088] In step S302, the target low-earth orbit satellites are marked as 1, that is, there is a link connection between the target low-earth orbit satellites and the receiving end in this time slice, and the remaining target low-earth orbit satellites are marked as 0, that is, there is no link connection between the target low-earth orbit satellites and the receiving end in this time slice.

[0089] In step S303, in each time slice, simulate the target low-earth orbit satellites with a link connection between the target low-earth orbit satellites and the receiving end on each link. Marking each target low-earth orbit satellite is beneficial for each link to correctly simulate the corresponding target low-earth orbit satellite and avoid problems such as bit errors caused by simulation errors.

[0090] In some embodiments, the low-earth orbit satellite link simulation method further includes steps S401 to S402:

[0091] S401: Obtain the discrete space-time link information matrix recording the space-time state and link state between each target low-earth orbit satellite and each receiving end, and convert the data corresponding to each time slice into single-frame image information.

[0092] S402: Perform a visual demonstration on the image information corresponding to consecutive time slices.

[0093] In step S401, convert the data of each time slice into one frame of image information according to the discrete space-time link information matrix. Each image information contains the space-time state and link parameters of the target low-earth orbit satellites and each receiving end. Converting the data corresponding to the time slice into graphic information is beneficial for subsequent conversion of the data before simulation into a video for comparison with the low-earth orbit satellite simulation video to observe the performance of each link.

[0094] In step S402, after the simulation of the graphic information corresponding to multiple consecutive time slices is completed, it is converted into a simulation video of the target low-earth orbit satellites for playback to realize the visualization of the simulation results and intuitively observe the status and position information of each target low-earth orbit satellite and the receiving end.

[0095] In some embodiments, the low-earth orbit satellite link simulation method further includes S501 to S502:

[0096] S501: Encapsulate the single-frame image information corresponding to each time slice into a video frame data packet, and add frame header information and frame tail information.

[0097] S502: During the transmission of the video frame data packet, when an interruption occurs, parse the data within the last data transmission cycle. If the frame tail information is matched, combine the frame tail information with the data that has been cached to form a video frame data packet; otherwise, place the data within the last data transmission cycle into the buffer and wait for subsequent data.

[0098] In step S501, one frame of image information is encapsulated into a video frame data packet, that is, frame header and frame tail data are added before the image information to form a video frame. The content of the video frame data packet includes a frame header identifier, an image frame position, an image resolution, image pixel information, and a frame tail identifier.

[0099] In some embodiments, the number of pixels in each frame after encapsulation is:

[0100] N pixel = m * n;

[0101] The number of bits of the image pixel information is:

[0102] bit pixel = N pixel * 3 * 8;

[0103] Among them, 3 represents three colors: red, green, and blue; 8 represents that each color is represented by eight-bit binary numbers.

[0104] The number of bits of the encapsulated data packet is:

[0105] bit pack = bit fhead + bit position + bit size + bit pixel + bit ftail ;

[0106] Among them, bit fhead is the number of bits of the frame header identifier, bit position is the number of bits of the frame position information, bit size is the number of bits of the resolution information, bit ftail is the number of bits of the frame tail identifier.

[0107] In step S502, the video frame data packet is transmitted with the wireless frame as the data transmission cycle. Since multiple data transmission cycles are required to complete the transmission of a video frame data packet, the software simulation platform provides a simulation interruption function, that is, after each wireless frame transmission is completed, an interruption detection is set, and the user can perform a simulation interruption operation in the interactive interface. The received video frame data packet with complete data information is restored to an image, and the service video image frame after transmission is obtained. The video frame data packets corresponding to the L receiving ends are restored respectively, and converted into videos and displayed on the software simulation platform at the same time. The transmitted videos received by the L receiving ends are played frame by frame with the original video to achieve the function of simulation visualization.

[0108] In some embodiments, the low-orbit satellite link simulation method further includes: based on the discrete space-time link information matrix obtained by simulation, the communication status of each target low-orbit satellite and each receiving end is evaluated, and an evaluation report is generated. After simulating the target low-orbit satellite, a simulation signal, i.e., a simulation result, is obtained, and the simulation result is converted into a low-orbit satellite simulation video, so that the simulation visualization is realized and the simulation transmission performance of each link is observed, so as to facilitate the subsequent adjustment of the motion trajectory, setting position and other parameters of the low-orbit satellite according to the simulation results, so that the actually set satellite can better transmit signals to the receiving end.

[0109] In other embodiments, the low-orbit satellite link simulation method of the present invention performs simulation operations on SKT satellite simulation software. The simulation of the low-orbit satellite link can show the problems in the satellite design as much as possible, facilitate timely discovery of problems and corrections, and save costs to the maximum extent. At the same time, it can be used to verify the feasibility of aerospace solutions. The present invention fully considers the characteristics of the low-orbit satellite communication network, such as large constellations, high-speed mobility, relatively short coverage period, and high connection density, so that the simulation results of the low-orbit satellite link simulation method of the present invention have a high degree of credibility.

[0110] The following is described in conjunction with a specific embodiment:

[0111] This embodiment provides a low-orbit satellite link simulation method, such as Figure 1 As shown, including:

[0112] Step 1: Establish the spatial constraint relationship of the low-orbit satellite link simulation platform

[0113] The main approach is to first construct a spherical cone simulation constraint space for the LEO (low-orbit satellite) beam-hopping channel scenario; then establish the space-time state information of each element in the simulation constraint space; finally, construct the low-orbit satellite ground link, unify the simulation time and space relationship, jointly use multi-color multiplexing SINR heat map, match spatial channel information, and establish the low-orbit satellite space-time link information matrix.

[0114] (1)Construct a spherical frustum simulation constraint space for the LEO hopping beam channel scenario:

[0115] Design a spherical frustum composed of a ground spherical cap surface and the highest orbit spherical cap surface of the constellation, with the two spherical cap surfaces as the bottom and top, to provide a closed space constraint for the simulation platform, and simulate the point-to-point link connection established between the satellite and the receiving end located within the curved frustum. Design the global area division grid and the minimum access elevation angle α of the coverage center point min-TN0 , to support the link performance simulation worldwide.

[0116] Specifically, corresponding to the spherical frustum simulation constraint space, the following can be specifically processed:

[0117] Construct a station-centered coordinate system: Through the simulation observation area selected by the user in the global area division grid, establish a station-centered coordinate system ENU with the center of the coverage area as the station center, where the X enu axis points to the due east, the Y enu points to the due north, and the Z enu points to the direction perpendicular to the ground upward. The elements in space are represented in the station coordinate system as:

[0118] P enu =(x enu ,y enu ,z enu );

[0119] Ground spherical cap surface SC tn : The ground space selected in the simulation platform is the earth's spherical cap surface, with a radius of the earth's radius R e , and its bottom is a circle with a radius of R TN , and the height of the spherical cap is H TN . The vertex of the spherical cap is the origin of the station-centered coordinate. The ground spherical cap surface satisfies in the station-centered coordinate system P enu-tn =(x enu-tn ,y enu-tn ,z enu-tn ):

[0120]

[0121]

[0122] Highest orbit spherical cap surface of the constellation SC sntn : With the origin of the station-centered coordinate system as the center and the center point coordinate as P TN0 =(0,0,0), construct a ray with the endpoint at P TN0 , and the elevation angle with the ground is the minimum access elevation angle α of the coverage center point min-TN0 . Rotate the ray 360° around the Z enu axis, and intersect with a circle with a radius of R e +h nmaxis tangent to the spherical surface, where h nmax is the highest satellite altitude among the ephemerides of N satellites obtained by the ephemeris calculation module. The obtained spherical cap surface is the highest orbit surface of the constellation, that is, the trajectories of the satellites that can provide communication support for the receiving end will not exceed this spherical cap surface in the simulation.

[0123] Calculate the projection of the highest orbit spherical cap surface of the constellation on the X enu OZ enu plane is a circle with radius R SNTN , then the coordinate representation P enu-sntn =(x enu-sntn ,y enu-sntn ,z enu-sntn ) of the highest orbit spherical cap surface of the constellation in the local-vertical local-horizontal coordinate system satisfies:

[0124]

[0125]

[0126] Spherical frustum simulation constraint space SCT constrain : Use the ground spherical cap surface SC tn as the bottom of the frustum, and use the highest orbit spherical cap surface SC sntn of the constellation as the top of the frustum to construct a spherical frustum simulation constraint space SCT constrain , and this spherical frustum simulation constraint space can include all link connections in the inspection area.

[0127] (2) Establish the spatio-temporal state information of each element in the simulation constraint space

[0128] The elements that the link simulation platform needs to focus on are located within the spherical frustum space constraint, including M low-earth orbit satellites S m that can provide communication support, and L mobile ground receiving terminals UE l . The simulation platform calculates the position trajectories of each satellite and each receiving terminal, and generates the spatial variation functions of each element corresponding to the satellite elevation angle α and time t in the geodetic coordinate system.

[0129] Specifically, for the spatial variation function corresponding to each element, it can be processed as follows:

[0130] Spatio-temporal state information INFO of low-earth orbit satellites s-m : According to the two-line orbital data TLE file input by the platform, including orbital inclination, right ascension of the ascending node, eccentricity, argument of periapsis, semi-major axis, and time of periapsis passage, generate the motion trajectories tle s-n-ecef (t), t ∈ T p , T p is the input satellite simulation inspection time range, and convert it to PTN0 is the station center coordinate system tle s-n-enu (t),t∈T p , calculation and spherical cone simulation constraint space SCT constrain Intersecting trajectories t s-n-enu (t),t∈T p :

[0131] t s-n-enu (t) = tle s-n-enu (t)∩SCT constrain , t∈T p ;

[0132] If t s-n-enu (t)=0,t∈T p , it means that the nth satellite cannot provide service to the receiver. t∈T p The number of satellites is set to M, and t' s-m-enu (t),t∈T s,m , T s,m is the time domain of the motion of the Mth satellite in the constrained space. s-m-enu (t) is converted to the longitude and latitude high coordinate system LLA to obtain the required simulated low-orbit satellite motion trajectory t s-m-lla (t)=(u lon (t),v lat (t),w alt (t)), where u lon is longitude, v lat is latitude, w alt is the altitude. s-m-lla (t) is derived to obtain the low-orbit satellite velocity V s-m (t), combined with T s,m , construct the space-time status information of M low-orbit satellites, INFO s-m (t s-m-lla (t),v s-m (t),T s,m ).

[0133] Ground mobile receiving end space-time status information INFO UE-l :The user inputs the ground receiving terminal information through the simulation platform, including the number of receiving terminals L, the receiving terminal motion trajectory t UE-l-lla (t), calculate the receiving end movement speed v UE-l (t) and the time domain T of the receiver moving in the constrained space ue,l , construct L ground mobile receiving end space-time state information, INFO UE-l (t UE-l-lla (t),v UE-l (t),Tue,l ).

[0134] (3) Create INFO L×M :Establish a link connection between the ground receiving end and the low-orbit satellite, and design a channel response information matrix INFO of size L×M L×M , where INFO l,m Represents the channel response information matrix between the lth ground receiver and the mth satellite. Unify the simulation time of the satellite and the receiver, and calculate the elevation angle α of the satellite relative to the receiver l,m ,Combined multi-color multiplexing SINR heat map and matching spatial channel information.

[0135] Specifically, the space-time link information matrix INFO corresponding to the receiving end l and the satellite m is l,m , which can be processed as follows:

[0136] Unify the simulation time of the satellite and the receiving end, and calculate their spatial relative relationship: extract the space-time state information INFO of the receiving end l UE-l (t UE-l-lla (t),v UE-l (t),T ue,l ) and the space-time status information INFO of the low-orbit satellite m s-m (t s-m-lla (t),v s-m (t),T s,m ), calculate T l,m =T ue,l ∩T s,m , where T l,m is the time domain in which the mth satellite and the lth satellite can establish a link connection in the constrained space. s-m-lla (t) and t UE-l-lla (t) Calculate the time-varying elevation angle α of satellite m relative to the receiver l l,m (t).

[0137] Joint multi-color multiplexing SINR heat map: extract ground coverage, satellite space-time status information, antenna parameters, multi-color multiplexing parameters, beam hopping parameters and link transmission configuration information, calculate the multi-beam pattern of the low-orbit satellite phased array, and calculate the SINR heat map of different beam positions for the selected ground coverage area during the mth satellite passing overhead m Extract T from the space-time state information of the receiving end UE-l-lla , calculate the SINR of the receiver l when communicating with the low-orbit satellite m l,m (t).

[0138] Matching spatial channel information: The simulation platform presets channel fading modeling CH under various geographical environments, extracts t UE-l-lla(t), according to the longitude and latitude of the earth, the geographical environment of the receiving end is matched, and the channel information CH matching when the low-orbit satellite m communicates with the receiving end l is generated l,m (t).

[0139] The low-orbit satellite trajectory t s-m-lla (t), low-orbit satellite motion speed v s-m (t), receiving end motion trajectory t UE-l-lla (t), receiving end movement speed v UE-l (t), the elevation angle α of satellite m relative to the receiving end l l,m (t), the time domain T in which the mth satellite and the lth satellite can establish a link connection in the constrained space l,m 、Signal to Interference and Noise Ratio Data Array SINR l,m (t), channel information CH l,m (t) and obtain the space-time link information matrix of the receiving end l and the satellite m:

[0140] INFO l,m (t s-m-lla (t),v s-m (t),t UE-l-lla (t),v UE-l (t),T l,m ,α l,m (t),SINR l,m (t),CH l,m (t));

[0141] Step 2: Establish time constraints for low-orbit satellite link simulation platform

[0142] The main approach is to first build a multi-satellite multi-user simulation timing grid in the constrained space; then establish discrete time slicing for link simulation based on variable time granularity; finally, design a multi-level parallel pipeline simulation mechanism including link simulation, link demonstration, and data storage.

[0143] Constructing a Timing Grid GRID for Multi-satellite Multi-user Simulation in Constrained Space SEQ-L×M :

[0144] Extract low-orbit satellite space-time link information matrix INFO L×M , which contains the link information of L ground mobile receiving terminals and M satellites. l,m In sequence, construct a multi-satellite multi-user simulation timing grid GRID with L rows and M columns corresponding to L ground mobile receiving terminals and M satellites SEQ-L×M .

[0145] The L×M links are assigned in sequence according to the simulation sequence of the corresponding satellite terminals, and the information matrix and simulation sequence SEQ of the links are recorded in the grid.l,m , GRID SEQ-l,m (INFO l,m , SEQ l,m ). SEQ l,m will be assigned according to SEQ l,m =(m - 1)L + l. When the link simulation module of the simulation platform runs, it will perform single-link or multi-link parallel simulation according to the simulation time sequence SEQ l,m for parallel simulation of single link or multiple links.

[0146] Design discrete time slices for link simulation based on variable time granularity:

[0147] Since the simulation platform is a pure software simulation platform, it is necessary to convert analog signals into digital signals for simulation. Design discrete time slices for link simulation based on variable time granularity to improve the operation efficiency of the simulation platform.

[0148] The specific implementation method is to set the number of time slices as K, that is, divide the satellite overpass time t m,end -t m,start into K time slices, and the time granularity is In the k time slice, the time is discretized as t k =k·G. Then in the time slice k, the spatial information and link parameters between the satellite and the receiving end do not change. Calculate the k-slice discrete space-time link information matrix of the receiving end l and the satellite m. Among them, for INFO l,m,k , it satisfies k·G∈(t m,start , t m,end ), For the link information matrix within the time slice of

[0149] INFO l,m,k (t s-m-lla (k·G), v s-m (k·G), t UE-l-lla (k·G), v UE-l (k·G), α l,m (k·G); t m,start , t m,end , T l,m , SINR l,m (k·G), CH l,m (k·G));

[0150] In the time slice k, the actual satellite communication duration corresponding to this slice, that is, the time granularity G, is mapped to the simulation communication duration t SIM,k in the simulation platform. SIM,k Users can adjust the efficiency and accuracy of link simulation by adjusting the granularity G and the simulation communication duration t of the time slice.

[0151] (3) Design a three - stage parallel pipeline simulation mechanism that includes data address fetching and link simulation, data analysis and link demonstration, and data storage:

[0152] The simulation platform supports single - link simulation and multi - link parallel simulation. The single - link simulation is carried out in sequence according to the simulation time sequence grid GRID SEQ-L×M in the simulation time sequence SEQ l,m from small to large; for multi - link parallel simulation, the simulation time sequence SEQ l,m is divided by L and rounded down. The simulation is carried out in ascending order according to the value. For links with the same value, parallel simulation is performed. The total number of time slices I for the simulation of these L links is I = K·L, where the time slice i, i ∈ (1, …, I) is the i - th time slice corresponding to the Q = (i - 1) mod L+1 - th link. On the basis of discrete time slices, the simulation platform sets the space - to - ground link within a time slice as the minimum link simulation unit for platform link simulation, and sets the longest time T T for completing a time - slice link simulation instruction as the minimum time period for platform link simulation. When performing simulation and demonstration on the link platform, multiple - segment tasks overlap, which can improve the efficiency of the link simulation platform. The specific implementation method is to divide the instructions for link platform simulation and demonstration into three segments:

[0153] Segment 1: Perform data address fetching and link simulation calculation on part of the links in slice i, read the discrete space - time link information matrix INFO l,m,k in time slice i and the link transmission parameters input by the user, including code rate CR, channel coding method CC, modulation method MOD, sub - carrier spacing SCS, bandwidth BW, electromagnetic frequency RF, etc., and the video service transmission data stream corresponding to time slice i, and perform low - earth - orbit satellite link simulation on it to obtain the simulated data stream;

[0154] Segment 2: Perform data analysis and link demonstration on part of the links in slice i, extract the transmission data stream before and after simulation, perform data analysis to obtain the key performance indicators of the low - earth - orbit satellite link. The specific indicators can be customized according to the user. Convert the output data stream into a video file and play it in comparison with the original video on the demonstration interface;

[0155] Segment 3: Store the simulation and demonstration files of slice i links, and store the simulation data such as the discrete space - time link information matrix INFO l,m,k in time segment i, the link transmission parameters input by the user, the data streams before and after transmission, and the key performance indicators.

[0156] The design includes a three-stage parallel pipeline simulation mechanism for data address fetching and link simulation, data analysis and link demonstration, and data storage. After reaching the steady state, three instructions can be completed in each subsequent clock cycle. That is, in time slice i (2 < i < I), data address fetching and link simulation for time slice i are performed, data analysis and link demonstration for time slice i - 1 are carried out, and data storage for time slice i - 2 is conducted.

[0157] Step 3: Design a visualization scheme for video service transmission in the low-earth orbit satellite link simulation platform

[0158] The main approach is as follows: First, design a video service data encapsulation method based on time-slice link simulation. Then, design a simulation data reception and simulation interruption mechanism. Finally, design a data visualization scheme for the link simulation platform.

[0159] Design a video service data encapsulation method based on time-slice link simulation:

[0160] The image information of each frame of the video is encapsulated as a video frame data packet. The content of the video frame data packet includes a frame header identifier, an image frame position, an image resolution, image pixel information, and a frame tail identifier. The specific processing is as follows: The resolution of the service video is m * n, the frame rate is F r , and the number of video frames is N f . The video is encapsulated in units of video frames and encoded in RGB encoding. The number of pixels in each frame is:

[0161] N pixel = m * n;

[0162] The number of bits of the image pixel information is:

[0163] bit pixel = N pixel * 3 * 8;

[0164] Among them, 3 represents three colors: red, green, and blue; 8 represents that each color is represented by eight binary digits.

[0165] The number of bits of the encapsulated data packet is:

[0166] bit pack = bit fhead + bit position + bit size + bit pixel + bit ftail ;

[0167] Among them, bit fhead is the number of bits of the frame header identifier, bit position is the number of bits of the frame position information, bit sizeis the number of bits of resolution information, bit ftail is the number of bits of the frame tail identifier.

[0168] In the simulation, the wireless frame format is designed according to the 5GNR protocol standard. The number of time slots required to transmit a data packet is:

[0169] N slot = bit pack / size tb ;

[0170] where size tb is the transmission block capacity.

[0171] The subcarrier spacing SCS = 2 u · 15 (KHz), the number of wireless frames required to transmit a data packet is:

[0172]

[0173] N frames of video frames can be transmitted within a time slice k: videoframe frame video frames:

[0174]

[0175] Design the simulation data reception and simulation interruption mechanism

[0176] In the simulation platform, after the wireless frame completes the link simulation, demodulation will be performed. After demodulation, the data will be cached, and the frame header identifier and frame tail identifier will be matched and recognized. After successful matching, the corresponding data will be retrieved, including the image frame position, image resolution, and image pigment information. The cache will be cleared, and the complete data information of the video frame will be received. The simulation platform provides a simulation interruption function, that is, after each wireless frame transmission ends, an interruption detection is set. The user can perform a simulation interruption operation on the interactive interface. If the interruption is triggered, the transmission will be paused starting from the completion of the wireless frame transmission, and at the same time, the current wireless frame will be demodulated and analyzed. If the frame tail is matched, the frame tail data will be combined with the data in the buffer area to form a complete data packet for subsequent image restoration operations; otherwise, the frame data will be stored in the buffer area waiting for subsequent data.

[0177] Design the data visualization scheme for the link simulation platform:

[0178] Perform the operation of restoring the data stream of the video frame data packet of the received complete data information to a video image, obtain the transmitted service video image frame, restore the video frame corresponding to each of the L receiving ends respectively, and at the same time, in the display module of the link simulation platform, play the transmitted video received by the L receiving ends frame by frame with the original video to achieve the function of video service visualization, and the link transmission performance can be observed through video playback.

[0179] In summary, for the low-Earth orbit satellite link simulation method and system of the present invention, a spherical frustum simulation constraint space oriented to the low-Earth orbit satellite channel scenario is constructed. According to the space-time state information of each low-Earth orbit satellite and the space-time state information of each receiving end in the spherical frustum simulation constraint space, a multi-satellite multi-user simulation timing grid within the spherical frustum simulation constraint space is constructed. A link simulation discrete time slice based on variable time granularity is established, and the link state within each time slice is simulated to obtain a discrete space-time link information matrix. According to the connection time domain between each target low-Earth orbit satellite and each receiving end, the time slices in which each link participates in the simulation are determined, and each link simulates the target low-Earth orbit satellite under the corresponding time slice. Single-link simulation and multi-link simulation methods are set up to simulate the low-Earth orbit satellite communication scenario with multiple low-Earth orbit satellites and multiple receiving ends, ensuring the integrity of the low-Earth orbit satellite link communication scenario simulation.

[0180] Further, the over-the-top time of each target low-Earth orbit satellite is divided into multiple time slices and the time granularity is calculated. During the simulation process, the efficiency and accuracy of the link simulation can be adjusted by adjusting the time granularity and the simulation communication duration of the time slice, improving the accuracy of the simulation.

[0181] Further, the simulation result after simulation is converted into a low-Earth orbit satellite simulation video, realizing the visualization of the low-Earth orbit satellite simulation result data.

[0182] Further, the discrete space-time link information matrix and the low-Earth orbit satellite simulation video obtained after simulation are analyzed to obtain the transmission performance of each link, and the parameters of the link with poor transmission performance are adjusted in time to avoid bit errors during the simulation process, improving the credibility of the simulation.

[0183] Further, a multi-level parallel pipeline simulation mechanism including link simulation, link demonstration, and data storage is designed, improving the simulation efficiency of the low-Earth orbit satellite link simulation.

[0184] Corresponding to the above method, the present invention also provides a system, which includes a computer device. The computer device includes a processor and a memory. Computer instructions are stored in the memory, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the system implements the steps of the method described above.

[0185] An embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the foregoing edge computing server deployment method are implemented. The computer-readable storage medium may be a tangible storage medium, such as a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, floppy disk, hard disk, removable storage disk, CD-ROM, or any other form of storage medium well-known in the art.

[0186] Those of ordinary skill in the art should understand that the various exemplary components, systems, and methods described in connection with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Specifically, whether to implement in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, and so on. When implemented in software, the elements of the present invention are programs or code segments for performing the required tasks. The program or code segment can be stored in a machine-readable medium or transmitted via a data signal carried in a carrier wave on a transmission medium or a communication link.

[0187] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present invention.

[0188] In the present invention, the features described and / or illustrated for one embodiment can be used in the same or similar manner in one or more other embodiments, and / or combined with the features of other embodiments or replace the features of other embodiments.

[0189] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for simulating a low-earth orbit satellite link, characterized in that, This method is carried out on a software simulation platform, and the method includes the following steps: Set up a simulation observation area, establish an earth spherical cap surface within the simulation observation area, establish a station-centered coordinate system with the center of the simulation observation area as the origin, and the vertex of the earth spherical cap surface coincides with the origin; obtain the orbital information of multiple low-earth orbit satellites to be simulated, construct rays with the origin as the endpoint, rotate and cut the sphere where the highest low-earth orbit satellite is located around the Z-axis of the station-centered coordinate system according to the minimum access elevation angle of the coverage center point to obtain the constellation's highest orbit spherical cap surface, and construct a spherical frustum simulation constraint space with the earth spherical cap surface as the bottom and the constellation's highest orbit spherical cap surface as the top; Obtain the motion trajectories of each low-earth orbit satellite in the spherical frustum simulation constraint space in the earth-centered inertial coordinate system and transform the motion trajectories into the station-centered coordinate system; calculate the intersection trajectories of each motion trajectory and the spherical frustum simulation constraint space to obtain the number of target low-earth orbit satellites serving the receiving end, and convert the intersection trajectories into the geodetic coordinate system to obtain the low-earth orbit satellite spatio-temporal state information corresponding to each target low-earth orbit satellite; obtain the number of receiving ends and the motion trajectories of each receiving end to obtain the spatio-temporal state information of each receiving end; According to the spatio-temporal state information of each low-earth orbit satellite and the spatio-temporal state information of each receiving end determine the time-domain order of the links constructed between each target low-earth orbit satellite and each receiving end, and mark the simulation sequence numbers for each link to construct a multi-star multi-user simulation timing grid; divide the overpass time of each target low-earth orbit satellite into multiple time slices, calculate the time granularity of each time slice, perform discrete operations on the spatio-temporal states and link parameters of the corresponding target low-earth orbit satellite and each receiving end based on the time granularity; simulate the link states within each time slice according to a preset model, and construct a discrete spatio-temporal link information matrix recording the spatio-temporal states and link states between each target low-earth orbit satellite and each receiving end; Among them, determine the time slices in which each link participates in the simulation according to the connection time domain of each target low-earth orbit satellite and the receiving end, and sequentially simulate the links to be simulated in each time slice. When the simulation is a single-link simulation, each link is sequentially simulated according to the simulation sequence number in the multi-star multi-user simulation timing grid; when the simulation is a multi-link simulation, divide the simulation sequence number of each link by the number of receiving ends and round down to obtain the corresponding simulation time value, and perform the simulation in ascending order of the simulation time value. For links with the same simulation time value, perform parallel simulation and output the simulation results; Simulate the link states within each time slice according to a preset model, and construct a discrete spatio-temporal link information matrix recording the spatio-temporal states and link states between each target low-earth orbit satellite and each receiving end, including: For a single time slice, calculate the time-varying elevation angle between the target low-earth orbit satellite and the receiving end according to the spatio-temporal state information of the low-earth orbit satellite and the spatio-temporal state information of the receiving end; For a single time slice, a signal-to-noise ratio heat map of different beam positions of the simulated observation area when the target low-orbit satellite passes over is calculated according to the link transmission configuration information, the simulated observation area, the space-time state information of the low-orbit satellite, antenna parameters, multi-color multiplexing parameters, and beam hopping parameters; and a signal-to-noise ratio of the receiving end when the target low-orbit satellite communicates is calculated according to the space-time state information of the receiving end; For a single time slice, multiple channel fading models are obtained, and channel information when the target low-orbit satellite communicates with the receiving end is generated according to the space-time state information of the receiving end and the geographical environment of the receiving end; The discrete space-time link information matrix is ​​obtained by combining the space-time state information of the low-orbit satellite, the space-time state information of the receiving end, the signal-to-noise ratio, the time-varying elevation angle and the channel information in each time slice; The time slices for each link to participate in the simulation are determined based on the connection time domain between each target low-orbit satellite and the receiving end, including: According to the discrete space-time link information matrix, finding the connection time domain of each target low-orbit satellite operating in the spherical cone simulation constraint space; Determine whether each time slice belongs to the connection time domain of each target low-orbit satellite. For each time slice, mark the target low-orbit satellite corresponding to the connection time domain to which it belongs as 1, and set the marks of other target low-orbit satellites to 0; In each time slice, only the target low-orbit satellite marked as 1 is simulated.

2. The low-earth orbit satellite link simulation method according to claim 1, wherein, The method further comprises: Obtain a discrete space-time link information matrix that records the space-time state and link state between each target low-orbit satellite and each receiving end, and convert the data corresponding to each time slice into single-frame image information; Provide a visual demonstration of the image information corresponding to continuous time slices.

3. The low-earth orbit satellite link simulation method according to claim 2, wherein The method further comprises: Encapsulate the single-frame image information corresponding to each time slice into a video frame data packet, and add frame header information and frame footer information; During the transmission of the video frame data packet, when an interruption occurs, the data in the last data sending cycle is parsed, and if the frame end information is matched, the frame end information is combined with the data that has been cached into a video frame data packet; otherwise, the data in the last data sending cycle is placed in the cache area and waits for subsequent data.

4. The low-earth orbit satellite link simulation method according to claim 1, characterized in that, The calculation formula of the simulation timing number is: SEQ l,m =(m - 1)L + l; Among them, SEQ l,m represents the sequence number during the simulation, m represents the m-th target low-earth orbit satellite, l represents the l-th receiving end, and L represents the total number of receiving ends.

5. The low-orbit satellite link simulation method according to claim 1, characterized in that, The link parameters include code rate, channel coding method, modulation method, subcarrier spacing, frequency bandwidth and electromagnetic frequency.

6. The low-earth orbit satellite link simulation method according to claim 1, wherein The method further comprises: performing performance evaluation on the communication status between each target low-orbit satellite and each receiving end according to the discrete space-time link information matrix obtained by simulation, and generating an evaluation report.

7. A low-earth orbit satellite link simulation system, comprising a processor and a memory, characterized in that, The memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the system implements the steps of the method as claimed in any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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