A method for satellite-to-ground link planning

Abstract

The application discloses a satellite-ground link planning method, which establishes a satellite-ground system model containing a certain number of satellites and ground stations, and proposes a "ground station-satellite bidirectional selection algorithm". Based on the consideration of satellite window time and satellite-ground station connection priority order, the algorithm firstly allows each ground station to connect the satellite with the longest window time of the maximum carrying capacity, and then allows the satellite to select the ground station to establish a link according to the priority order, so that the longest satellite-ground link in the system model is solved at the update time interval, the satellite routing table update frequency is reduced, and the satellite-ground transmission efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of satellite mobile communication, and particularly relates to a satellite-to-ground link planning method that considers satellite window time and allows for bidirectional selection between ground stations and satellites. Background Technology

[0002] In recent years, with fifth-generation mobile communication technology (5G, 5G) th The rapid development of terrestrial networks, represented by the Generation 5G, has met users' demands for greater communication capacity, faster data rates, lower transmission latency, and higher service quality, thus giving rise to numerous new business needs and scenarios. However, due to limitations such as terrestrial deployment conditions, remote areas like oceans and deserts face the problem of ineffective terrestrial network coverage. Satellites, as a communication facility capable of achieving wide coverage and large-scale access, can precisely solve these problems of terrestrial networks, providing an effective supplement and extension.

[0003] Large-scale networking of Low Earth Orbit (LEO) satellites creates a global LEO satellite network. LEO satellite networks offer advantages unmatched by traditional terrestrial networks, including wide-area coverage, massive access, and no need for ground deployment, providing global communication access services. Within an LEO satellite network, for a ground area covered by multiple LEO satellites, there are communication scenarios where ground base stations and multiple LEO satellites coexist. Therefore, the design of an integrated LEO satellite-ground network system must consider the connection process between multiple satellites and multiple ground stations. Optimizing the pairing and connection between satellites and ground stations within the satellite network becomes crucial.

[0004] In the fourth generation (4G, 4 th During the era of Long Term Evolution (LTE) mobile communication, a considerable amount of research has been conducted on LTE and satellite mobile communication, which has laid a solid foundation for solving the aforementioned problem of pairing and connecting satellites and ground stations. Summary of the Invention

[0005] The purpose of this invention is to provide a satellite-to-ground link planning method to solve the technical problems of satellite-to-ground link connections in existing satellite networks.

[0006] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0007] A satellite-to-ground link planning method includes the following steps:

[0008] S1: The satellite periodically broadcasts its current location information and the data it carries;

[0009] S2: The ground station calculates and obtains the satellite window (i.e., the duration during which the satellite can maintain a connection with the base station) based on the satellite's position information (i.e., ephemeris);

[0010] S3: Calculate the satellite's priority based on the importance of the data it carries, the level of the organization to which the satellite belongs, and its previous connections with ground stations; use a s Let a represent the priority of the s-th satellite. s =α a ×info s +β a ×history s +γ a ×institution s ; among which, info s This indicates the importance of the information carried by the s-th satellite, history s =1 indicates that the s-th satellite successfully established a satellite-to-ground link last time. s α represents the organization to which the s-th satellite belongs. a Indicates info s The weights, β a Represents history s The weights of γ; a Institution s The weights;

[0011] S4: Construct a satellite-to-ground link model containing M satellites and N ground stations; Satellites: {S1,S2,S3,…,S…} m Ground station: {G1,G2,G3,…G} n}, where S s G represents the s-th satellite in the system, with a total of m satellites; g Let m represent the g-th ground station in the system, with a total of n ground stations, where m >> n;

[0012] And determine the objective function and constraints;

[0013] Objective function:

[0014] Maximize the duration of the satellite ground station link that can be maintained for the shortest possible time;

[0015] Constraints:

[0016] Each ground station can connect to a limited number of satellites;

[0017] A satellite can only establish a connection with one ground station at a time.

[0018] The satellite can maintain a connection with the ground station for a limited time (low-Earth orbit satellites are not geostationary satellites and require a process of switching ground stations to maintain the connection).

[0019] S5: A two-way selection algorithm for ground station satellites is proposed. The specific steps of the algorithm are as follows:

[0020] S5.1 Ground station connects to satellite;

[0021] S5.2 The satellite selects ground stations according to priority order;

[0022] S5.3, If the priority is a s If there is more than one virtual connection when a satellite establishes a link, then, in addition to the ground station that successfully established the link, the other ground stations that established virtual connections are recorded with priority a. s The satellite is selected, and another satellite (if it exists) within the visible range outside the recorded satellite is selected to establish a virtual connection;

[0023] S5.4 Iterate continuously until all satellites that can connect to a ground station select a specific ground station as the connection target;

[0024] The algorithm enables ground station satellites to select each other according to their own priority order in order to calculate the optimal solution of the objective function, that is, to calculate the satellite-ground station connection mode that can maintain the connection between the satellite and the ground station for the longest time in the shortest possible time in the satellite-ground link model.

[0025] S6. Based on the link connection method calculated by the ground station-satellite bidirectional selection algorithm, match the satellite and the ground station and establish the actual link connection.

[0026] Furthermore, the objective function of step S4

[0027] Among them, g sg This indicates the link establishment status between the s-th satellite and the g-th ground station. s∈{1,2,3,…,M}, g∈{1,2,3,…,N}, T sg This indicates the duration of the link between the s-th satellite and the g-th ground station;

[0028] Constraints:

[0029]

[0030]

[0031] T sg <∞

[0032] Where, N g This represents the maximum number of satellites that the g-th ground station can connect to.

[0033] Furthermore, step S5 specifically includes the following steps:

[0034] S5.1 Ground station connects to satellite:

[0035] If P g >N g Then G g According to T sg Choose N from largest to smallest. g Virtual connections are established between the satellites;

[0036] If P g ≤N g Then G g Virtually connect all observable satellites;

[0037] Among them, P g G represents g Number of observable satellites, T sg This represents the time during which the s-th satellite and the g-th ground station can maintain a connection.

[0038] S5.2. Satellites select ground stations according to priority order:

[0039] Use b g Let g represent the priority of the g-th ground station, then:

[0040] b g =α b ×T sg +β b ×velocity g

[0041] Velocity g α represents the speed at which the g-th ground station processes information. b T represents sg The weights, β b Represents velocity g The weights;

[0042] make

[0043]

[0044] Among them, SG sg This represents the actual connection status between the s-th satellite and the g-th ground station;

[0045] Then for priority a s The satellite is set to exist in q gIf a ground station establishes a virtual connection with it, then the satellite will be assigned a priority level based on the ground station's priority b. g Select a ground station to establish an actual connection, i.e.

[0046] SG sg =1

[0047] Where, q g Representative and priority is a s The number of ground stations that establish virtual connections with satellites;

[0048] S5.3, If the priority is a s If there is more than one virtual connection when a satellite establishes a link, then, in addition to the ground station that successfully established the link, the other ground stations that established virtual connections are recorded with priority a. s The satellite, while simultaneously selecting another satellite within the visible range outside the recorded satellite to establish a virtual connection;

[0049] S5.4 Iterate continuously until all satellites that can establish virtual connections with the ground station successfully establish links with the ground station.

[0050] Furthermore, step S6 specifically includes the following steps:

[0051] Step S6.1:

[0052] SG sg =1

[0053] Then an actual connection is established between the s-th satellite and the g-th ground station;

[0054] Step S6.2:

[0055] SG sg =0

[0056] There is no actual connection between the s-th satellite and the g-th ground station.

[0057] The satellite-to-ground link planning method of the present invention has the following advantages:

[0058] 1) Based on the consideration of the priority order of satellite windows and satellite ground station connections, a "ground station satellite bidirectional selection algorithm" is proposed. The algorithm establishes a satellite-to-ground link by mutual selection between ground station satellites according to their own priorities. It fully considers conditions such as satellite window duration, satellite-owning organization, and the importance of information carried by the satellite, ensuring the rationality and stability of the satellite-to-ground link, reducing the number of routing table updates, and improving the efficiency of satellite-to-ground information transmission.

[0059] 2) The algorithm converges quickly, and the final satellite-to-ground link can be calculated in no more than M iterations (the number of satellites included in the satellite-to-ground link model).

[0060] 3) It has a wide range of applications. As long as the number and distribution information of satellites and ground stations are given, the algorithm can be used to plan the optimal satellite-to-ground link.

[0061] 4) It has strong scalability. By changing the priority calculation method of the satellite ground station, factors such as weather that affect the satellite-to-ground link connection can be taken into account. Attached Figure Description

[0062] Figure 1 This is a flowchart of a satellite-to-ground link planning method according to the present invention. Detailed Implementation

[0063] To better understand the purpose, structure, and function of this invention, a satellite-to-ground link planning method of this invention will be described in further detail below with reference to the accompanying drawings.

[0064] This specific implementation discloses a satellite-to-ground link planning method, such as... Figure 1 As shown, it includes the following steps:

[0065] S1: The satellite periodically broadcasts its current location information and the data it carries;

[0066] S2: The ground station calculates and obtains the satellite window (i.e., the duration during which the satellite can maintain a connection with the base station) based on the satellite's position information (i.e., ephemeris);

[0067] S3: Calculate the satellite's priority based on whether the data carried by the satellite needs to be transmitted to the ground immediately, the organization to which the satellite belongs, and the satellite's previous connection with the ground station;

[0068] S4: Construct a satellite-to-ground link model containing M satellites and N ground stations, and determine the objective function and constraints;

[0069] 1. Satellite-Ground System Model:

[0070] satellite:

[0071] {S1,S2,S3,…,S m}

[0072] Ground station:

[0073] {G1,G2,G3,…G n}

[0074] Among them, S s G represents the s-th satellite in the system (out of m satellites). g This represents the g-th ground station in the system (out of a total of n ground stations).

[0075] (Generally, m >> n)

[0076] 2. Objective function and constraints

[0077] Objective function:

[0078] Maximize the duration of the satellite-to-ground link that can be maintained for the shortest possible time.

[0079] Constraints:

[0080] Each ground station can connect to a limited number of satellites;

[0081] A satellite can only establish a connection with one ground station at a time.

[0082] The time that a satellite can maintain a connection with a ground station is limited (low-Earth orbit satellites are not geostationary satellites and require a process of switching ground stations to maintain a connection).

[0083] make

[0084]

[0085] in,

[0086] S s ∈{S1,S2,S3,…,S m}

[0087] G g ∈{G1,G2,G3,…G n}

[0088] Right now

[0089] s∈{1,2,3,…,m}

[0090] g∈{1,2,3,…,n}

[0091] structure

[0092]

[0093] The link selection optimization problem can then be written as:

[0094]

[0095]

[0096]

[0097] T sg <∞

[0098] Where, N g T represents the maximum number of satellites that the g-th ground station can connect to. sg This represents the duration of the link between the s-th satellite and the g-th ground station.

[0099] S5: A "ground station-satellite bidirectional selection algorithm" is proposed to calculate the optimal solution of the objective function, that is, to calculate the satellite-ground station connection mode that can maintain the connection between the satellite and the ground station for the longest time while keeping the connection in the shortest possible time in the satellite-ground link model.

[0100] 1. Ground station connects to satellite

[0101] If P g >N g Then G g According to T sg Choose N from largest to smallest. g Virtual connection between satellites

[0102] If P g ≤N g Then G g Virtually connect all observable satellites

[0103] Among them, P g G represents g The number of observable satellites, N g T represents the maximum number of satellites that the g-th ground station can connect to. sg This represents the time during which the s-th satellite and the g-th ground station can maintain a connection.

[0104] 2. Satellites select ground stations according to priority order.

[0105] Use a s Let a represent the priority of the s-th satellite. s =α a ×info s +β a ×history s +γ a ×institution s

[0106] Among them, info s This indicates the importance of the information carried by the s-th satellite, history s =1 indicates that the s-th satellite successfully established a satellite-to-ground link last time. s α represents the organization to which the s-th satellite belongs. a β a γ a They represent info s history s and institutions s The weights;

[0107] Use b g If b represents the priority of the g-th ground station, then bg =α b ×T sg +β b ×velocity g

[0108] Among them, T sg Velocity represents the time that the s-th satellite and the g-th ground station can maintain a connection. g α represents the speed at which the g-th ground station processes information. b β b T represents respectively sg and velocity g The weight.

[0109] make

[0110]

[0111] Then for priority a s The satellite, assuming there exists q g If a ground station establishes a virtual connection with it, then the satellite will be assigned a priority level based on the ground station's priority b. g Select a ground station to establish an actual connection, i.e.

[0112] SG sg =1

[0113] Where, q g Representative and priority is a s The number of ground stations that establish virtual connections with the satellite.

[0114] 3. If the priority is a s If there is more than one virtual connection when a satellite establishes a link, then, in addition to the ground station that successfully established the link, the other ground stations that established virtual connections are recorded with priority a. s The satellite is selected, and another satellite (if it exists) within the visible range outside the recorded satellite is selected to establish a virtual connection.

[0115] 4. Iterate continuously until all satellites capable of connecting to a ground station select a specific ground station as their connection target. At this point...

[0116] S6: Based on the link connection method calculated by the "ground station-satellite bidirectional selection algorithm", the satellite and the ground station are matched and the actual link is connected. 1.

[0118] SG sg =1

[0119] Then an actual connection is established between the s-th satellite and the g-th ground station. 2.

[0121] SG sg =0

[0122] There is no actual connection between the s-th satellite and the g-th ground station.

[0123] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A satellite-to-ground link planning method, characterized in that, Includes the following steps: S1: The satellite periodically broadcasts its current location information and the data it carries; S2: The ground station calculates the satellite window, i.e., the duration for which the satellite can maintain a connection with the base station, based on the satellite's position information, i.e., ephemeris. S3: The satellite's priority is calculated based on the importance of the data it carries, the level of the organization to which it belongs, and its previous connections with ground stations; using... Indicates the first The priority of each satellite, then ;in, Indicates the first The importance of the information carried by each satellite Indicates the first The last time the satellite successfully established a satellite-to-ground link, Indicates the first The organization to which the satellite belongs, express The weight, express The weights; express The weights; S4: Construct a system containing satellites and A ground station satellite-to-ground link model; Satellite: Ground station: ,in, Represents the first in the system 1 satellite, total One satellite; Represents the first in the system There are 1 ground station, total One ground station, And determine the objective function and constraints; the objective function in step S4 ; in, Indicates the first satellite and the first The link establishment status of each ground station ， ， ， , Indicates the first satellite and the first How long can the links between ground stations be maintained? Constraints: in, Indicates the first The maximum number of satellites that a ground station can connect to; S5: A two-way selection algorithm for ground station satellites is proposed. The specific steps of the algorithm are as follows: S5.1 Ground station connects to satellite: like ,but according to Choose from largest to smallest Virtual connections are established between the satellites; like ,but Virtually connect all observable satellites; in, express Number of observable satellites Indicates the first The satellite and the first The time a ground station can maintain a connection; S5.

2. Satellites select ground stations according to priority order: use Indicates the first The satellite and the first The priority of each ground station is as follows: ； in Indicates the first The speed at which a ground station processes information. express The weight, express The weights; make ； in, Representing the satellite and the first The actual connection status of each ground station; Then for priority The satellite is set to exist If a ground station establishes a virtual connection with it, then the satellite will be determined according to the priority of the s-th satellite and the g-th ground station. Select a ground station to establish an actual connection, i.e. ； in, Representatives and priorities are The number of ground stations that establish virtual connections with satellites; S5.3, if the priority is If there is more than one virtual connection when a satellite establishes a link, then, in addition to the ground station that successfully established the link, the other ground stations that established virtual connections are recorded with a priority of [priority]. The satellite, while simultaneously selecting another satellite within the visible range outside the recorded satellite to establish a virtual connection; S5.4 Iterate continuously until all satellites capable of establishing virtual connections with the ground station successfully establish links with the ground station. S6. Based on the link connection method calculated by the ground station-satellite bidirectional selection algorithm, match the satellite and the ground station and establish the actual link connection.

2. The satellite-to-ground link planning method according to claim 1, characterized in that, Step S6 specifically includes the following steps: Step S6.1: ； Then in the satellite and the first Establish physical connections between ground stations; Step S6.2: ； Then the first satellite and the first There is no actual connection between the ground stations.

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