Satellite-to-ground link processing method, device and network equipment

Abstract

The present invention provides a satellite-to-ground link processing method, device and network equipment, and relates to the field of communication technology. The method includes: obtaining the visibility information of the ground station and the satellite at each moment in a first time period and the communication requirements between the ground station pairs; determining the first satellite-to-ground link with the minimum delay between the ground station pairs with communication requirements according to the visibility information and communication requirements at the first moment; if the communication requirements have not changed at the second moment, determining the second satellite-to-ground link with the minimum delay between the ground station pairs with communication requirements at the second moment according to the first satellite-to-ground link; wherein the second moment is after the first moment; if the communication requirements change at the second moment, determining the second satellite-to-ground link according to the visibility information and communication requirements at the second moment. The solution of the present invention can solve the problems of high switching frequency, high delay and high jitter in the current satellite-to-ground link processing solution.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a satellite-to-ground link processing method, device and network equipment. Background Art

[0002] In recent years, the use of giant low-orbit satellite constellations to provide global Internet services has attracted great attention. By integrating satellite networks with existing ground networks (i.e., integrated ground-ground networks), it is expected to provide a wider range of low-latency, high-bandwidth network services. Among them, the integrated ground-ground networking structure will play a fundamental and key role in network performance.

[0003] The existing integrated space-ground network consists of thousands of low-orbit satellites and participates in network routing. There are mainly the following solutions for satellite-to-ground link processing: First, the ground station always chooses to connect to the satellite closest to it (Nearest Satellite and Handover when a closer satellite exists, NSH). In this way, although the ground station can always connect to the satellite with lower latency and stronger signal strength, the distance between the satellite and the ground station is constantly changing, and the frequency of ground station connecting and switching satellites is too high. Each switch requires re-convergence of the route, which brings huge routing convergence overhead and poor network accessibility. Second, the ground station chooses to connect to the satellite closest to itself and disconnect until the satellite is no longer visible (Nearest Satellite until Disappearing, NSD). Although the satellite switching frequency is lower than that of the first method, the switching frequency is still relatively high and the network accessibility is still not high. The third method is that the ground station connects to the satellite with the longest visible time (Longest Remaining Service Time, LRST). For the ground station, the switching frequency can be the lowest, but for the ground station pairs, there are problems of high latency and high jitter. Summary of the invention

[0004] The purpose of the present invention is to provide a satellite-to-ground link processing method, device and network equipment to solve the problems of high switching frequency, high delay and high jitter in the current satellite-to-ground link processing scheme.

[0005] To achieve the above object, an embodiment of the present invention provides a satellite-to-ground link processing method, comprising:

[0006] Obtain visibility information between the ground station and the satellite and communication requirements between ground stations at each moment in a first time period; wherein the first time period includes a plurality of moments separated by a preset step length;

[0007] Determine, according to the visibility information and the communication demand at a first moment, a first satellite-to-ground link with the smallest delay between ground station pairs with communication demand; wherein the first moment is one of the multiple moments;

[0008] If the communication demand does not change at the second moment, determining, according to the first satellite-to-ground link, a second satellite-to-ground link with the smallest delay between ground station pairs with communication demand at the second moment; wherein the second moment is one of the multiple moments, and the second moment is after the first moment;

[0009] If the communication demand at the second moment changes, the second satellite-to-ground link is determined according to the visibility information and the communication demand at the second moment.

[0010] Optionally, the visibility information includes: a visibility relationship between each ground station and each satellite at each time, and / or a remaining visibility duration between each ground station and each satellite at each time;

[0011] The visibility relationship includes whether the satellite is visible or invisible to the ground station.

[0012] Optionally, obtaining visibility information of the ground station and the satellite at each moment in the first time period includes:

[0013] Obtain satellite parameters at each moment in the first time period;

[0014] Determining the visibility relationship between each ground station and each satellite at each time according to the satellite parameters;

[0015] According to the visibility relationship, the remaining visibility duration between each ground station and each satellite at each moment is determined.

[0016] Optionally, determining, according to the visibility information and the communication demand at the first moment, a first satellite-to-ground link having a minimum delay between ground station pairs having communication demand comprises:

[0017] For each ground station, determining, according to the visibility information at the first moment, a set of target satellites whose remaining visibility duration exceeds a preset threshold;

[0018] For each ground station, determining a first target satellite in the target satellite set; wherein the first target satellite is a satellite with the smallest delay between ground stations with communication requirements;

[0019] The first satellite-to-ground link is determined according to the first target satellite of each ground station.

[0020] Optionally, determining, for each ground station, a first target satellite in the target satellite set includes:

[0021] For each ground station, a target gathering point is determined according to the target satellite set and the running directions of the satellites in the target satellite set; wherein the target gathering point is a point where the sum of distances to satellites in the same running direction is the smallest and the distances between different ground stations with communication requirements are the smallest;

[0022] The satellite with the smallest distance from the target gathering points corresponding to different ground stations with communication needs is determined as the first target satellite.

[0023] Optionally, determining, for each ground station, a target gathering point according to the target satellite set and the running directions of satellites in the target satellite set includes:

[0024] For each ground station, the target satellite set is divided into at least two candidate satellite sets according to the running directions of the satellites; wherein the running directions of the satellites in one candidate satellite set are the same, and the running directions of the satellites in different candidate satellite sets are different;

[0025] For each candidate satellite set, determine a first clustering point of the candidate satellite set according to the position information of each satellite in the candidate satellite set; wherein the first clustering point is a point having the smallest sum of distances to each satellite in the candidate satellite set;

[0026] For each ground station, the point with the smallest distance from the first gathering point of different ground stations with communication needs is determined as the target gathering point.

[0027] Optionally, determining, for each candidate satellite set, a first clustering point of the candidate satellite set according to position information of each satellite in the candidate satellite set includes:

[0028] For each candidate satellite set, determine the position information of each satellite in the candidate satellite set mapped to a two-dimensional grid; wherein the position information includes the orbit number of the satellite and the number of the satellite in the orbit;

[0029] For each candidate satellite set, a point in the two-dimensional grid having the smallest sum of distances from each satellite is determined as the first clustering point.

[0030] Optionally, the determining, according to the first satellite-to-ground link, a second satellite-to-ground link having a minimum delay between ground station pairs having communication requirements at the second moment includes:

[0031] If it is determined that the satellite-to-ground link needs to be switched at the second moment according to the visibility relationship between the first moment and the second moment, determining the second satellite-to-ground link according to the first satellite-to-ground link based on a rule of minimum routing hops;

[0032] If it is determined, based on the visibility relationship between the first moment and the second moment, that there is no need to switch the satellite-to-ground link at the second moment, the first satellite-to-ground link is determined as the second satellite-to-ground link.

[0033] Optionally, the determining the second satellite-to-ground link according to the first satellite-to-ground link based on a rule of minimum routing hops includes:

[0034] Determine, according to the first satellite-to-ground link, a set of candidate satellites corresponding to each ground station at the second time; wherein the set of candidate satellites includes a plurality of first satellites whose remaining visible duration exceeds a preset threshold, and the first satellites and the second satellites in the first satellite-to-ground link corresponding to the ground station have the same running direction;

[0035] For each ground station's candidate satellite set, determine a second target satellite in the candidate satellite set; wherein the second target satellite is a satellite with the smallest number of routing hops relative to the second satellite;

[0036] The second satellite-to-ground link is determined according to the second target satellite.

[0037] Optionally, the determining, for the candidate satellite set for each ground station, a second target satellite in the candidate satellite set includes:

[0038] For each ground station's candidate satellite set, determine an offset between each satellite in the candidate satellite set and the second satellite to obtain an offset set corresponding to each ground station;

[0039] Determine a first offset with the highest frequency from the set of offsets of all ground stations;

[0040] For each ground station, if the first offset exists in the offset set corresponding to the ground station, a satellite that is offset by the first offset relative to the second satellite is determined as the second target satellite;

[0041] For each ground station, if the first offset does not exist in the offset set corresponding to the ground station, a second offset with the smallest offset relative to the first offset in the offset set is determined, and a satellite offset by the second offset relative to the second satellite is determined as the second target satellite.

[0042] To achieve the above object, an embodiment of the present invention provides a satellite-to-ground link processing device, including:

[0043] An acquisition module, used to acquire visibility information between a ground station and a satellite and communication requirements between ground stations at each moment in a first time period; wherein the first time period includes a plurality of moments separated by a preset step length;

[0044] A first processing module is configured to determine, according to the visibility information and the communication demand at a first moment, a first satellite-to-ground link with the smallest delay between ground station pairs with communication demand; wherein the first moment is one of the multiple moments;

[0045] a second processing module, configured to determine, if the communication demand does not change at a second moment, a second satellite-to-ground link having the smallest delay between ground station pairs having communication demand at the second moment according to the first satellite-to-ground link; wherein the second moment is one of the multiple moments, and the second moment is after the first moment;

[0046] a third processing module, configured to determine, if the communication requirement at the second moment changes, the second satellite-to-ground link according to the visibility information and the communication requirement at the second moment

[0047] To achieve the above-mentioned purpose, an embodiment of the present invention provides a communication device, including a transceiver, a processor, a memory, and a program or instruction stored in the memory and executable on the processor; when the processor executes the program or instruction, the steps in the satellite-to-ground link processing method as described above are implemented.

[0048] To achieve the above objective, an embodiment of the present invention provides a readable storage medium on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps in the satellite-to-ground link processing method as described above are implemented.

[0049] The beneficial effects of the above technical solution of the present invention are as follows:

[0050] In an embodiment of the present invention, by obtaining the visibility information of the ground station and the satellite and the communication demand between the ground station pairs at each moment in the first time period, and determining the first satellite-to-ground link with the minimum delay between the ground station pairs with communication demand according to the visibility information and the communication demand at the first moment, and if the communication demand does not change at the second moment, then according to the first satellite-to-ground link, determine the second satellite-to-ground link with the minimum delay between the ground station pairs with communication demand at the second moment, and if the communication demand changes at the second moment, then determine the second satellite-to-ground link according to the visibility information and the communication demand at the second moment. In this way, the satellite-to-ground topology is solved based on the topology design algorithm at a single moment, so that the average delay between the ground station pairs with communication demand is as small as possible, and the satellite-to-ground topology at the next moment is determined according to the change of the communication demand, so that the average delay between the ground station pairs with communication demand at the next moment can be as small as possible, and satellite switching can be reduced, thereby ensuring high network accessibility between nodes of the integrated space-ground network while reducing the delay and jitter between ground station pairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is one of the flow charts of the satellite-to-ground link processing method according to an embodiment of the present invention;

[0052] Figure 2 This is a second flowchart of the satellite-to-ground link processing method according to an embodiment of the present invention;

[0053] Figure 3 A flowchart of a topology design algorithm at a single moment in an embodiment of the present invention;

[0054] Figure 4 A schematic diagram of mapping satellites visible from a ground station to a grid according to an embodiment of the present invention;

[0055] Figure 5 A flowchart of an algorithm for satellite-to-ground topology conversion according to an embodiment of the present invention;

[0056] Figure 6 is a block diagram of a satellite-to-ground link processing device according to an embodiment of the present invention;

[0057] Figure 7 A block diagram of a network device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0059] It should be understood that the references to "one embodiment" or "an embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present invention. Therefore, the references to "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0060] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the following processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0061] Additionally, the terms "system" and "network" are often used interchangeably herein.

[0062] In the embodiments provided in the present application, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0063] In recent years, there have been relevant studies on the inter-satellite topology design of low-orbit satellite constellations. However, due to the small scale of early low-orbit satellite constellations represented by Iridium and Globalstar in the late 20th century, consisting of less than 100 satellites, there is little space for satellite-to-ground topology design; and traditional satellites use bent pipe technology for communication, that is, only physical pathways are established and they do not participate in network routing. Therefore, the satellite-to-ground topology will only affect the connection between the satellite and the ground station, and will not affect the satellite constellation. Therefore, the satellite-to-ground topology design requires simplicity and a single standard, and there is relatively little research on the satellite-to-ground topology.

[0064] like Figure 1 As shown, a satellite-to-ground link processing method according to an embodiment of the present invention includes the following steps:

[0065] Step 11: Obtain visibility information between the ground station and the satellite and communication requirements between ground stations at each moment in a first time period; wherein the first time period includes multiple moments separated by a preset step size.

[0066] Optionally, the first time period is a period of time after the current system time, that is, obtaining the visibility information of the ground station and the satellite at each moment in the first time period can be understood as predicting the visibility information of the ground station and the satellite in a period of time after the current system time. For example: the start time of the first time period is T0, and the end time is Tn. The visibility information of the ground station and the satellite at the moment T0, moment T1, moment T2, ..., moment Tk, ..., moment Tn in the period of time from T0 to Tn can be obtained, wherein adjacent times can be separated by a time unit (i.e., the preset step length), and the determination method and specific duration of the time unit are not specifically limited in the embodiments of the present invention.

[0067] Optionally, the visibility information includes: the visibility relationship between each ground station and each satellite at each moment, and / or the remaining visibility time between each ground station and each satellite at each moment; wherein the visibility relationship includes whether the satellite is visible or invisible to the ground station.

[0068] Optionally, the communication demand (or traffic demand) between ground station pairs can be obtained in a similar manner to the above-mentioned method of obtaining visibility information; or, the communication demand of the ground station pair at the initial moment is first obtained, and the change of the communication demand is determined at the next moment, etc., which is not limited to the embodiments of the present invention. Among them, the ground station pair can refer to multiple ground stations.

[0069] Step 12: Determine a first satellite-to-ground link with the smallest delay between ground station pairs with communication needs based on the visibility information and the communication needs at a first moment; wherein the first moment is one of the multiple moments.

[0070] Optionally, the satellite-to-ground link can also be referred to as a satellite-to-ground topology, that is, a satellite link structure composed of satellites connected to multiple ground stations. In this embodiment, based on the visibility information of each ground station and each satellite at the predicted first moment and the communication requirements between ground station pairs, the satellite-to-ground topology is solved based on a topology design algorithm at a single moment, so that the average delay between ground station pairs with communication requirements is as small as possible, and the connection status between the ground station and the satellite at the first moment is obtained, that is, the first satellite-to-ground link. Among them, the ground station with communication requirements can be understood as a ground station that has a communication service request to transmit or process, etc.

[0071] Step 13: If the communication demand has not changed at the second moment, determine, based on the first satellite-to-ground link, a second satellite-to-ground link with the smallest delay between ground stations with communication demand at the second moment; wherein the second moment is one of the multiple moments, and the second moment is after the first moment.

[0072] Optionally, the second moment may be located after the first moment and adjacent to the first moment. In this embodiment, after determining the first satellite-to-ground link with the smallest delay between ground station pairs with communication needs according to the visibility information and the communication needs at the first moment, if the communication needs between ground station pairs at the next moment do not change, the satellite-to-ground link at the next moment may be determined according to the satellite-to-ground link solved at the first moment, so that the average delay between ground station pairs with communication needs at the next moment is as small as possible and satellite switching is reduced.

[0073] Step 14: If the communication demand at the second moment changes, determining the second satellite-to-ground link according to the visibility information and the communication demand at the second moment.

[0074] In the above scheme, the visibility information of the ground station and the satellite and the communication requirements between the ground station pairs at each moment in the first time period are obtained, and the first satellite-to-ground link with the smallest delay between the ground station pairs with communication requirements is determined according to the visibility information and the communication requirements at the first moment, and if the communication requirements do not change at the second moment, the second satellite-to-ground link with the smallest delay between the ground station pairs with communication requirements at the second moment is determined according to the first satellite-to-ground link, and if the communication requirements change at the second moment, the second satellite-to-ground link is determined according to the visibility information and the communication requirements at the second moment. In this way, the satellite-to-ground topology is solved based on the topology design algorithm at a single moment, so that the average delay between the ground station pairs with communication requirements is as small as possible, and the satellite-to-ground topology at the next moment is determined according to the change of the communication requirements, so that the average delay between the ground station pairs with communication requirements at the next moment can be as small as possible, and satellite switching can be reduced, thereby ensuring high network accessibility between nodes of the integrated space-ground network while reducing delays and jitters between ground station pairs.

[0075] Optionally, the inter-satellite topology structure may adopt a +Grid structure, that is, a satellite establishes stable inter-satellite links with two adjacent satellites in the same orbit and two satellites in adjacent orbits.

[0076] Optionally, obtaining visibility information of the ground station and the satellite at each moment in the first time period includes:

[0077] Obtain satellite parameters at each moment in the first time period; determine the visibility relationship between each ground station and each satellite at each moment based on the satellite parameters; determine the remaining visibility time between each ground station and each satellite at each moment based on the visibility relationship.

[0078] Optionally, the satellite parameters may include satellite positions (such as longitude, latitude, altitude, etc.). In this embodiment, by predicting the satellite positions in a future time period, the visibility relationship between each ground station and each satellite at each moment in the time period is calculated, such as the visibility relationship can also be calculated based on the satellite position and the minimum elevation angle requirement of the ground station. Further, based on the visibility relationship, the remaining visible time of each ground station and each satellite at each moment in the time period can be calculated; wherein, the remaining visible time can also be calculated based on the minimum elevation angle of the ground station and the satellite position.

[0079] The satellite-to-ground link processing method of the embodiment of the present invention can be applied in scenarios such as inclined orbit satellite constellations and globally distributed ground stations. This scheme calculates the visibility relationship between the ground station and the satellite based on the predicted satellite parameters (such as satellite position data); according to the communication requirements between the ground stations, the topology design algorithm at a single moment is run to approximate the satellite-to-ground topology with the minimum average delay between the ground station pairs in need; according to the changes in the visibility relationship, the connection and disconnection of the satellite-to-ground links of multiple ground stations are coordinated and managed, and the satellite-to-ground topology transformation algorithm is run to approximate the satellite-to-ground topology with the minimum average maximum delay between the ground station pairs in need within a time period. Among them, the inter-satellite topology can adopt a +Grid structure, that is, a satellite only connects the front and rear two satellites in the same orbit and the left and right two satellites in the adjacent orbit. The routing algorithm can adopt the shortest path algorithm, and the number of hops is used to represent the delay. The number of hops between ground station pairs can be obtained using the Dijkstra algorithm. The specific process is as follows Figure 2 As shown, the specific steps include:

[0080] Step 21: Predict satellite parameters (such as satellite position data) in a future time period, and calculate the visibility relationship between each ground station and each satellite in the time period, such as can be calculated based on the minimum elevation angle requirement of the ground station; wherein the visibility relationship is used to characterize the visibility or invisibility between each ground station and each satellite.

[0081] Furthermore, based on the visibility relationship, the remaining visible duration of each ground station and each satellite at each moment in the time period can be calculated. For each moment in the time period, it is sequentially determined whether each ground station and each satellite should establish a satellite-to-ground link at each moment.

[0082] Step 22: Initialize the communication requirements between the ground station pairs (such as the traffic requirements between the ground station pairs).

[0083] Step 23: Run the topology design algorithm at a single moment to solve the satellite-ground topology so that the average delay between ground station pairs with communication needs is as small as possible, and obtain the connection status between the ground station and the satellite at the current moment t (if t is one of the moments T0, T1, T2, ..., Tk, ..., Tn in the period of T0 to Tn), that is, obtain the first satellite-to-ground link with the minimum delay between ground station pairs at the current moment t, and update the current moment t to the next moment.

[0084] Step 24: Determine whether the communication demand between ground stations at the current time t has changed. If so, return to step 22; otherwise, execute step 25 sequentially.

[0085] Step 25: Determine whether the satellite-to-ground link established at the last moment must be disconnected, such as whether there is a link between a satellite and a ground station at the last moment, but the visibility relationship is not satisfied at the current moment. If not, execute step 26 in sequence; otherwise, jump to step 27.

[0086] Step 26: Since the satellite-to-ground link established at the last moment can still be connected, in order to maintain topology stability and network reachability, the established satellite-to-ground link is not disconnected or reconnected, and the current moment t is updated to the next moment, and the process returns to step 24.

[0087] Step 27: Since the satellite-ground topology at the previous moment is obtained by minimizing the average delay between ground station pairs, in order to maintain low delay and low delay jitter, the satellite-ground topology conversion algorithm is run, that is, the satellite-ground topology at the current moment will be converted according to the satellite-ground topology at the previous moment, and the number of routing hops between ground station pairs will be kept unchanged as much as possible, and the current moment will be updated to the next moment, and then jump to step 24 to continue execution.

[0088] In the above steps, if the updated current time exceeds the predicted time period, the process ends. After the above steps are completed, the satellite positions of subsequent time periods can be continuously predicted according to actual needs, and the above steps can be repeated to achieve continuous prediction.

[0089] Optionally, determining, according to the visibility information and the communication demand at the first moment, a first satellite-to-ground link having a minimum delay between ground station pairs having communication demand comprises:

[0090] For each ground station, based on the visibility information at the first moment, determine a set of target satellites whose remaining visibility time exceeds a preset threshold; for each ground station, determine a first target satellite in the set of target satellites; wherein the first target satellite is a satellite with the smallest delay between ground station pairs with communication needs; and determine the first satellite-to-ground link based on the first target satellite of each ground station.

[0091] For example: for 2 ground stations, ground station 1 corresponds to 3 visible satellites, of which there are 2 satellites whose remaining visible time exceeds the preset threshold at the first moment, then these two satellites are determined as the target satellite set corresponding to ground station 1; ground station 2 corresponds to 4 visible satellites, of which there are 3 satellites whose remaining visible time exceeds the preset threshold at the first moment, then the 3 visible satellites are determined as the target satellite set corresponding to ground station 2.

[0092] Furthermore, a satellite that minimizes the delay between ground stations with communication needs is selected from the target satellite set corresponding to ground station 1, which is the first target satellite corresponding to ground station 1; correspondingly, a satellite that minimizes the delay between ground stations with communication needs is selected from the target satellite set corresponding to ground station 2, which is the first target satellite corresponding to ground station 2. In this way, the first target satellite corresponding to ground station 1 and the first target satellite corresponding to ground station 2 constitute the first satellite-to-ground link at the first moment, and minimize the delay between ground stations with communication needs.

[0093] Optionally, determining, for each ground station, a first target satellite in the target satellite set includes:

[0094] For each ground station, a target gathering point is determined according to the target satellite set and the moving directions of the satellites in the target satellite set; wherein the target gathering point is a point where the sum of distances to satellites in the same moving direction is the smallest and the distances between different ground stations with communication needs are the smallest; the satellite with the smallest sum of distances to the target gathering points corresponding to different ground stations with communication needs is determined as the first target satellite.

[0095] For example, as an implementation method, for each ground station, determining a target gathering point according to the target satellite set and the satellite movement directions in the target satellite set includes:

[0096] For each ground station, the target satellite set is divided into at least two candidate satellite sets according to the satellite's running direction; wherein the satellites in one candidate satellite set have the same running direction, and the satellites in different candidate satellite sets have different running directions; for each candidate satellite set, a first gathering point of the candidate satellite set is determined according to the position information of each satellite in the candidate satellite set; wherein the first gathering point is a point with the smallest sum of distances from each satellite in the candidate satellite set; for each ground station, a point with the smallest sum of distances from the first gathering points of different ground stations with communication needs is determined as the target gathering point.

[0097] For another example, as another implementation, for each ground station, determining a target gathering point according to the target satellite set and the satellite movement directions in the target satellite set includes:

[0098] Each satellite in the target satellite set for each ground station can be marked with its corresponding running direction. In this way, based on the target satellite set, the point with the minimum sum of distances from satellites in the same running direction and the minimum distance between different ground stations with communication needs can be calculated, which is the target gathering point.

[0099] Optionally, determining, for each candidate satellite set, a first clustering point of the candidate satellite set according to position information of each satellite in the candidate satellite set includes:

[0100] For each candidate satellite set, determine the position information of each satellite in the candidate satellite set mapped to the two-dimensional grid; wherein the position information includes the orbit number of the satellite and the number of the satellite in the orbit; for each candidate satellite set, determine the point in the two-dimensional grid with the minimum sum of distances to each satellite as the first gathering point.

[0101] Specifically, since there are many visible satellites above each ground station, it is not advisable to directly traverse all satellite-to-ground topologies to obtain the satellite-to-ground topology with the minimum number of hops between ground station pairs with communication needs. Therefore, the present invention finds two representative satellites from the visible satellites of each ground station for solution, such as Figure 3 As shown, the specific steps include:

[0102] Step 31: Map the satellites whose visible duration over each ground station exceeds the preset threshold θ at the current moment onto a two-dimensional grid according to the position coding method of (orbit number, number within the orbit), where the horizontal axis of the two-dimensional grid is the number of orbits and the vertical axis is the number of satellites within the orbit; wherein the maximum setting of θ cannot exceed the longest visible duration between each ground station and the visible satellite. For example, a constellation with 34 orbits and 34 satellites in each orbit, such as Figure 4 As shown, a schematic diagram of the mapping of satellites connected to 6 ground stations at a certain moment is given. In this embodiment, the "distance" between two points on the grid can be used to represent the minimum number of hops between two satellites. Among them, the calculation of the "distance" between any two points on the grid is different from the Euclidean distance. Instead, the "distance" between any two points is represented by the sum of the inter-orbit number difference and the intra-orbit number difference between satellites.

[0103] Step 32: The visible satellites whose visibility duration at each ground station exceeds θ are divided into two subsets according to the satellite's movement direction (such as the movement direction from south to north and the movement direction from north to south), namely, two candidate satellite sets.

[0104] Step 33: Calculate the clustering point of each candidate satellite set respectively, where the clustering point is the point where the sum of the “distances” from the ground station to each satellite in the candidate satellite set (mapped to the points on the two-dimensional grid) is the minimum. In this way, each ground station has two representative points, i.e., the clustering points of two candidate satellite sets.

[0105] Step 34: Determine a subset of the clustering point set composed of the above clustering points, the subset includes a target clustering point for each ground station, and the target clustering point makes the distance between clustering points of ground stations with communication needs the shortest. In this way, each ground station obtains a target clustering point.

[0106] Step 35: For each ground station, a satellite is selected from the candidate satellite set corresponding to its target cluster point so that the sum of the distances between the target cluster points of the ground station with communication needs is minimized. This satellite is the satellite selected by the ground station for connection at the current moment, i.e., the first target satellite.

[0107] Optionally, the determining, according to the first satellite-to-ground link, a second satellite-to-ground link having a minimum delay between ground station pairs having communication requirements at the second moment includes:

[0108] If it is determined according to the visibility relationship between the first moment and the second moment that the satellite-to-ground link needs to be switched at the second moment, the second satellite-to-ground link is determined according to the first satellite-to-ground link based on a rule of minimum routing hops; if it is determined according to the visibility relationship between the first moment and the second moment that the satellite-to-ground link does not need to be switched at the second moment, the first satellite-to-ground link is determined as the second satellite-to-ground link.

[0109] For example: determine whether the satellite-to-ground link established at the last moment must be disconnected, such as whether there is a link between a certain satellite and a ground station at the last moment, but the visibility relationship is not satisfied at the current moment. If not, the first satellite-to-ground link is determined as the second satellite-to-ground link, that is, when the satellite-to-ground link established at the last moment can continue to be connected, in order to maintain topological stability and network accessibility, the established satellite-to-ground link is not disconnected or reconnected. Otherwise, according to the first satellite-to-ground link, the second satellite-to-ground link is determined based on the rule of minimum routing hops, that is, the satellite-to-ground topology at the previous moment is obtained by minimizing the average delay between ground station pairs with communication needs. In order to maintain low delay and low delay jitter, the satellite-to-ground topology conversion algorithm is run, that is, the satellite-to-ground topology at the current moment will be converted according to the satellite-to-ground topology at the last moment, and the routing hops between ground station pairs with communication needs are kept unchanged or minimized as much as possible.

[0110] Optionally, the determining the second satellite-to-ground link according to the first satellite-to-ground link based on a rule of minimum routing hops includes:

[0111] According to the first satellite-to-ground link, a candidate satellite set corresponding to each ground station at the second moment is determined; wherein the candidate satellite set includes multiple first satellites whose remaining visible time exceeds a preset threshold, and the first satellites and the second satellite in the first satellite-to-ground link corresponding to the ground station have the same running direction; for the candidate satellite set of each ground station, a second target satellite in the candidate satellite set is determined; wherein the second target satellite is a satellite with the smallest number of routing hops relative to the second satellite; and according to the second target satellite, the second satellite-to-ground link is determined.

[0112] The second satellite may be understood as the satellite to which the corresponding ground station is connected at the first moment, that is, the satellite to which the corresponding ground station is connected in the first satellite-to-ground link.

[0113] Optionally, the determining, for the candidate satellite set for each ground station, a second target satellite in the candidate satellite set includes:

[0114] For each ground station's candidate satellite set, determine the offset between each satellite in the candidate satellite set and the second satellite to obtain an offset set corresponding to each ground station; determine the first offset with the highest frequency from the offset sets of all ground stations; for each ground station, if the first offset exists in the offset set corresponding to the ground station, determine the satellite that is offset by the first offset relative to the second satellite as the second target satellite; for each ground station, if the first offset does not exist in the offset set corresponding to the ground station, determine the second offset with the smallest offset relative to the first offset in the offset set, and determine the satellite that is offset by the second offset relative to the second satellite as the second target satellite.

[0115] In this embodiment, the satellite-to-ground topology conversion algorithm is used, that is, the second satellite-to-ground link is determined based on the rule of minimum routing hops according to the first satellite-to-ground link. On the basis of the satellite-to-ground topology structure at the previous moment (i.e., the first moment), the satellite-to-ground links of all ground stations are switched synchronously, on the one hand, the frequency of satellite-to-ground topology changes in the entire network is reduced; on the other hand, by making all ground stations switch connected satellites according to similar change degrees, the similarity between the overall satellite-to-ground topology at the current moment (i.e., the second moment) and the satellite-to-ground topology at the previous moment (i.e., the first moment) can be maintained as much as possible, while maintaining the low delay characteristics between ground stations at the previous moment, the delay jitter between ground stations is reduced.

[0116] Specifically, Figure 5 As shown in the figure, the process of the satellite-to-ground topology conversion algorithm includes:

[0117] Step 51: Filter out a set of candidate satellites whose corresponding visible duration of each ground station at the current moment (ie, the second moment) exceeds a preset threshold θ and whose running direction is the same as that of the connected satellite at the previous moment (ie, the first moment).

[0118] Step 52: For each candidate satellite set corresponding to each ground station, calculate the offset between each satellite in the corresponding candidate satellite set and the satellite connected at the previous moment (i.e., the first moment), and mark the offset according to (orbit number difference, intra-orbit number difference), so as to generate the satellite offset set of the ground station based on these offsets.

[0119] Step 53: Determine the most frequently appearing element (i.e., offset) in the satellite offset set of each ground station. If the most frequently appearing element (i.e., offset) exists in the satellite offset set of a ground station, then the satellite selected for connection at the current moment (i.e., the second moment) is the satellite whose offset with the satellite at the previous moment (i.e., the first moment) is the most frequently appearing element; otherwise, the satellite selected for connection is the offset with the smallest distance from the most frequently appearing element in the satellite offset set corresponding to the ground station at the previous moment (i.e., the first moment).

[0120] In an embodiment of the present invention, by predicting satellite parameters in a future time period, the visibility relationship and the remaining visibility time between each ground station and each satellite at each moment are calculated; according to the predicted or known communication requirements between ground station pairs, a topology design algorithm based on a single moment is used to approximate the satellite-ground topology with the minimum average delay between the required ground station pairs, while ensuring a low frequency of network topology changes (i.e., higher network accessibility).

[0121] Among them, the topology design algorithm for a single moment is to map the satellites whose visibility duration of each ground station exceeds a preset threshold at the current moment to a two-dimensional grid according to a certain position coding method, and use the distance between two points on the grid to represent the minimum number of hops between two satellites; the visible satellites whose visibility duration of each ground station exceeds the preset threshold are divided into two subsets according to the satellite's movement direction (i.e., a set of candidate satellites running from north to south and a set of candidate satellites running from south to north), and the clustering points in these two sets are found respectively; based on the goal of minimizing the delay between ground station pairs with communication needs, a clustering point is selected for each ground station, and further according to this goal, the satellite to be connected is selected from the set of candidate satellites corresponding to the selected clustering point, and the current moment is updated to the next moment.

[0122] Furthermore, after updating the current moment, if it is determined that the satellite-to-ground link established at the previous moment must be disconnected, that is, there is a link between a certain satellite and a ground station at the previous moment, but the visibility relationship is not satisfied at the current moment, the satellite-to-ground topology conversion algorithm is run. Since the topology at the previous moment is obtained by minimizing the average delay between ground station pairs, in order to maintain low delay and low delay jitter, the topology at the current moment will be converted based on the topology at the previous moment, and the number of routing hops between ground station pairs will be kept unchanged or minimized as much as possible.

[0123] 1. Among them, the satellite-to-ground topology conversion algorithm is based on the satellite-to-ground topology structure at the previous moment and the visibility relationship between the ground station and the satellite at the current moment, so as to obtain the satellite-to-ground topology at the current moment. Specifically, it includes: screening out a set of candidate satellites whose visibility duration of each ground station exceeds a preset threshold and whose running direction is the same as the direction of the connected satellite at the previous moment; calculating the offset set of candidate satellites according to the offset of the candidate satellite set of each ground station and the connected satellite at the previous moment (orbit number difference, orbit number difference); according to the distribution of offsets in the offset set of all ground stations, based on the principle of making the offsets of all ground stations switching satellites as similar as possible, determine the offset of the connected satellite, thereby determining the satellite to be connected. In this way, the scheme can greatly reduce the delay and jitter between nodes in the integrated space-ground network.

[0124] Compared with the NSH and NSD methods in the prior art, the embodiments of the present invention can greatly improve network accessibility; compared with the LRST method in the prior art, the network accessibility can be maintained. In the embodiments of the present application, when selecting a satellite for connection, the remaining visible time of the satellite will be first screened, and only satellites whose remaining visible time reaches a certain threshold will be further selected. At the same time, when switching, multiple ground stations will switch as synchronously as possible, so that the satellite switching moments between ground station pairs are as unified as possible, that is, the routing convergence process is unified to the same time period, which can further reduce the overall routing convergence time and improve network accessibility.

[0125] like Figure 6 As shown, an embodiment of the present invention provides a satellite-to-ground link processing device 600, comprising:

[0126] An acquisition module 610 is used to acquire visibility information between a ground station and a satellite and communication requirements between ground stations at each moment in a first time period; wherein the first time period includes a plurality of moments separated by a preset step length;

[0127] A first processing module 620 is configured to determine a first satellite-to-ground link with the smallest delay between ground station pairs with communication requirements according to the visibility information and the communication requirements at a first moment; wherein the first moment is one of the multiple moments;

[0128] A second processing module 630 is configured to determine, if the communication demand at the second moment does not change, a second satellite-to-ground link with the smallest delay between ground station pairs with communication demand at the second moment according to the first satellite-to-ground link; wherein the second moment is one of the multiple moments and the second moment is after the first moment;

[0129] The third processing module 640 is configured to determine the second satellite-to-ground link according to the visibility information and the communication demand at the second moment if the communication demand at the second moment changes.

[0130] Optionally, the visibility information includes: a visibility relationship between each ground station and each satellite at each time, and / or a remaining visibility duration between each ground station and each satellite at each time;

[0131] The visibility relationship includes whether the satellite is visible or invisible to the ground station.

[0132] Optionally, the acquisition module 610 includes:

[0133] An acquisition submodule, used to acquire satellite parameters at each moment in the first time period;

[0134] A first processing submodule, configured to determine the visibility relationship between each ground station and each satellite at each time according to the satellite parameters;

[0135] The second processing submodule is used to determine the remaining visibility time between each ground station and each satellite at each moment according to the visibility relationship.

[0136] Optionally, the first processing module 620 includes:

[0137] A third processing submodule is used to determine, for each ground station, a set of target satellites whose remaining visibility duration exceeds a preset threshold according to the visibility information at the first moment;

[0138] A fourth processing submodule is used to determine, for each ground station, a first target satellite in the target satellite set; wherein the first target satellite is a satellite with the smallest delay between ground stations with communication requirements;

[0139] The fifth processing submodule is used to determine the first satellite-to-ground link according to the first target satellite of each ground station.

[0140] Optionally, the fourth processing submodule includes:

[0141] A first processing unit is used to determine, for each ground station, a target gathering point according to the target satellite set and the satellite movement directions in the target satellite set; wherein the target gathering point is a point where the sum of distances to satellites in the same movement direction is the smallest and the distances between different ground stations with communication requirements are the smallest;

[0142] The second processing unit is used to determine the satellite with the smallest distance from the target gathering point corresponding to different ground stations with communication needs as the first target satellite.

[0143] Optionally, the first processing unit includes:

[0144] a dividing subunit, configured to divide the target satellite set into at least two candidate satellite sets according to the running directions of the satellites for each ground station; wherein the running directions of the satellites in one candidate satellite set are the same, and the running directions of the satellites in different candidate satellite sets are different;

[0145] A first processing subunit is configured to determine, for each candidate satellite set, a first clustering point of the candidate satellite set according to the position information of each satellite in the candidate satellite set; wherein the first clustering point is a point having a minimum sum of distances to each satellite in the candidate satellite set;

[0146] The second processing subunit is used to determine, for each ground station, a point with the smallest distance from the first gathering points of different ground stations with communication needs as the target gathering point.

[0147] Optionally, the first processing subunit is further configured to:

[0148] For each candidate satellite set, determine the position information of each satellite in the candidate satellite set mapped to a two-dimensional grid; wherein the position information includes the orbit number of the satellite and the number of the satellite in the orbit;

[0149] For each candidate satellite set, a point in the two-dimensional grid having the smallest sum of distances from each satellite is determined as the first clustering point.

[0150] Optionally, the third processing module 640 includes:

[0151] a sixth processing submodule, configured to determine the second satellite-to-ground link based on the first satellite-to-ground link and based on a rule of minimum routing hops if it is determined that the satellite-to-ground link needs to be switched at the second moment according to the visibility relationship between the first moment and the second moment;

[0152] The seventh processing submodule is configured to determine the first satellite-to-ground link as the second satellite-to-ground link if it is determined that there is no need to switch the satellite-to-ground link at the second moment according to the visibility relationship between the first moment and the second moment.

[0153] Optionally, the sixth processing submodule includes:

[0154] a third processing unit, configured to determine, according to the first satellite-to-ground link, a set of candidate satellites corresponding to each ground station at the second moment; wherein the set of candidate satellites includes a plurality of first satellites whose remaining visible duration exceeds a preset threshold, and the first satellites and the second satellite in the first satellite-to-ground link corresponding to the ground station have the same running direction;

[0155] a fourth processing unit, configured to determine, for each ground station's candidate satellite set, a second target satellite in the candidate satellite set; wherein the second target satellite is a satellite with the smallest number of routing hops relative to the second satellite;

[0156] The fifth processing unit is used to determine the second satellite-to-ground link according to the second target satellite.

[0157] Optionally, the fourth processing unit includes:

[0158] A third processing subunit is used to determine, for each ground station's candidate satellite set, an offset between each satellite in the candidate satellite set and the second satellite, and obtain an offset set corresponding to each ground station;

[0159] A fourth processing subunit is used to determine a first offset with the highest frequency from the offset sets of all ground stations;

[0160] a fifth processing subunit, configured to, for each ground station, determine, if the first offset exists in the offset set corresponding to the ground station, a satellite that is offset by the first offset relative to the second satellite as the second target satellite;

[0161] The sixth processing subunit is used to determine, for each ground station, a second offset with the smallest offset relative to the first offset in the offset set if the first offset does not exist in the offset set corresponding to the ground station, and determine the satellite with the second offset relative to the second satellite as the second target satellite.

[0162] The device of this embodiment corresponds to the above method, can implement the steps of each embodiment of the above method, and can achieve the same technical effect. To avoid repetition, it will not be described here.

[0163] A network device according to an embodiment of the present invention, such as Figure 7As shown, it includes a transceiver 710, a processor 700, a memory 720, and a program or instruction stored in the memory 720 and executable on the processor 700; when the processor 700 executes the program or instruction, the steps applied to the satellite-to-ground link processing method are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0164] The transceiver 710 is used to receive and send data under the control of the processor 700.

[0165] Among them, Figure 7 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically linking together various circuits of one or more processors represented by processor 700 and memory represented by memory 720. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 710 may be a plurality of components, i.e., including a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium. The processor 700 is responsible for managing the bus architecture and general processing, and the memory 720 may store data used by the processor 700 when performing operations.

[0166] A readable storage medium according to an embodiment of the present invention stores a program or instruction thereon. When the program or instruction is executed by a processor, the steps in the satellite-to-ground link processing method as described above are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0167] The processor is a processor in the network device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0168] It should be further explained that the terminals described in this specification include but are not limited to smart phones, tablet computers, etc., and many of the functional components described are called modules in order to more particularly emphasize the independence of their implementation methods.

[0169] In the embodiment of the present invention, module can be implemented with software so that it can be executed by various types of processors. For example, an executable code module of an identification can include one or more physical or logical blocks of computer instructions, for example, it can be constructed as an object, process or function. Nevertheless, the executable code of the identified module does not need to be physically located together, but can include different instructions stored in different positions, and when these instructions are logically combined together, it constitutes a module and realizes the specified purpose of the module.

[0170] In fact, executable code module can be a single instruction or many instructions, and can even be distributed on a plurality of different code segments, distributed among different programs, and distributed across a plurality of memory devices. Similarly, operating data can be identified in the module, and can be implemented and organized in the data structure of any appropriate type according to any appropriate form. The operating data can be collected as a single data set, or can be distributed in different locations (including on different storage devices), and can only be present on a system or network as an electronic signal at least in part.

[0171] When a module can be implemented by software, considering the level of existing hardware technology, a person skilled in the art can build a corresponding hardware circuit to implement the corresponding function of the module that can be implemented by software without considering the cost. The hardware circuit includes a conventional very large scale integration (VLSI) circuit or gate array and existing semiconductors such as logic chips, transistors, or other discrete components. The module can also be implemented by a programmable hardware device, such as a field programmable gate array, a programmable array logic, a programmable logic device, etc.

[0172] The above exemplary embodiments are described with reference to the accompanying drawings, and many different forms and embodiments are feasible without departing from the spirit and teachings of the present invention. Therefore, the present invention should not be constructed as a limitation of the exemplary embodiments proposed herein. More specifically, these exemplary embodiments are provided so that the present invention will be perfect and complete, and the scope of the present invention will be conveyed to those who are familiar with the technology. In these figures, the component sizes and relative sizes may be exaggerated for clarity. The terms used here are only based on the purpose of describing specific exemplary embodiments and are not intended to be limiting. As used herein, unless the text clearly indicates otherwise, the singular forms "one", "an" and "the" are intended to include these multiple forms. It will be further understood that the terms "including" and / or "comprising" when used in this specification indicate the presence of the features, integers, steps, operations, components and / or components, but do not exclude the presence or increase of one or more other features, integers, steps, operations, components, components and / or their groups. Unless otherwise indicated, when stated, a range of values ​​includes the upper and lower limits of that range and any subranges therebetween.

[0173] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A satellite-to-ground link processing method, characterized in that: include: Obtain visibility information between the ground station and the satellite and communication requirements between the ground stations at each moment in a first time period; wherein the first time period includes a plurality of moments separated by a preset step length; Determine, according to the visibility information and the communication demand at a first moment, a first satellite-to-ground link with the smallest delay between ground station pairs with communication demand; wherein the first moment is one of the multiple moments; If the communication demand does not change at the second moment, determining, according to the first satellite-to-ground link, a second satellite-to-ground link with the smallest delay between ground station pairs with communication demand at the second moment; wherein the second moment is one of the multiple moments, and the second moment is after the first moment; If the communication requirement at the second moment changes, determining the second satellite-to-ground link according to the visibility information and the communication requirement at the second moment; The visibility information includes: the visibility relationship between each ground station and each satellite at each time, and / or the remaining visibility duration between each ground station and each satellite at each time; The visibility relationship includes whether the satellite is visible or invisible to the ground station; The determining, according to the visibility information and the communication demand at the first moment, a first satellite-to-ground link with the smallest delay between ground station pairs with communication demand comprises: For each ground station, determining, according to the visibility information at the first moment, a set of target satellites whose remaining visibility duration exceeds a preset threshold; For each ground station, determining a first target satellite in the target satellite set; wherein the first target satellite is a satellite with the smallest delay between ground stations with communication requirements; The first satellite-to-ground link is determined according to the first target satellite of each ground station.

2. The method according to claim 1, characterized in that The obtaining of visibility information of the ground station and the satellite at each moment in the first time period includes: Obtain satellite parameters at each moment in the first time period; Determining the visibility relationship between each ground station and each satellite at each time according to the satellite parameters; According to the visibility relationship, the remaining visibility duration between each ground station and each satellite at each moment is determined.

3. The method according to claim 1, characterized in that The step of determining, for each ground station, a first target satellite in the target satellite set comprises: For each ground station, a target gathering point is determined according to the target satellite set and the running directions of the satellites in the target satellite set; wherein the target gathering point is a point where the sum of distances to satellites in the same running direction is the smallest and the distances between different ground stations with communication requirements are the smallest; The satellite with the smallest distance from the target gathering points corresponding to different ground stations with communication needs is determined as the first target satellite.

4. The method according to claim 3, characterized in that The step of determining, for each ground station, a target gathering point according to the target satellite set and the running directions of satellites in the target satellite set comprises: For each ground station, the target satellite set is divided into at least two candidate satellite sets according to the running directions of the satellites; wherein the running directions of the satellites in one candidate satellite set are the same, and the running directions of the satellites in different candidate satellite sets are different; For each candidate satellite set, determine a first clustering point of the candidate satellite set according to the position information of each satellite in the candidate satellite set; wherein the first clustering point is a point having the smallest sum of distances to each satellite in the candidate satellite set; For each ground station, the point with the smallest distance from the first gathering point of different ground stations with communication needs is determined as the target gathering point.

5. The method according to claim 4, characterized in that The step of determining, for each candidate satellite set, a first clustering point of the candidate satellite set according to position information of each satellite in the candidate satellite set comprises: For each candidate satellite set, determine the position information of each satellite in the candidate satellite set mapped to a two-dimensional grid; wherein the position information includes the orbit number of the satellite and the number of the satellite in the orbit; For each candidate satellite set, a point in the two-dimensional grid having the smallest sum of distances from each satellite is determined as the first clustering point.

6. The method according to claim 1, characterized in that The determining, according to the first satellite-to-ground link, a second satellite-to-ground link having the smallest delay between ground stations having communication requirements at the second moment, comprises: If it is determined that the satellite-to-ground link needs to be switched at the second moment according to the visibility relationship between the first moment and the second moment, determining the second satellite-to-ground link according to the first satellite-to-ground link based on a rule of minimum routing hops; If it is determined, based on the visibility relationship between the first moment and the second moment, that there is no need to switch the satellite-to-ground link at the second moment, the first satellite-to-ground link is determined as the second satellite-to-ground link.

7. The method according to claim 6, characterized in that The determining the second satellite-to-ground link according to the first satellite-to-ground link based on a rule of minimum routing hops includes: Determine, according to the first satellite-to-ground link, a set of candidate satellites corresponding to each ground station at the second time; wherein the set of candidate satellites includes a plurality of first satellites whose remaining visible duration exceeds a preset threshold, and the first satellites and the second satellites in the first satellite-to-ground link corresponding to the ground station have the same running direction; For each ground station's candidate satellite set, determine a second target satellite in the candidate satellite set; wherein the second target satellite is a satellite with the smallest number of routing hops relative to the second satellite; The second satellite-to-ground link is determined according to the second target satellite.

8. The method according to claim 7, characterized in that The step of determining a second target satellite in the candidate satellite set for each ground station includes: For each ground station's candidate satellite set, determine an offset between each satellite in the candidate satellite set and the second satellite to obtain an offset set corresponding to each ground station; Determine a first offset with the highest frequency from the set of offsets of all ground stations; For each ground station, if the first offset exists in the offset set corresponding to the ground station, a satellite that is offset by the first offset relative to the second satellite is determined as the second target satellite; For each ground station, if the first offset does not exist in the offset set corresponding to the ground station, a second offset with the smallest offset relative to the first offset in the offset set is determined, and a satellite offset by the second offset relative to the second satellite is determined as the second target satellite.

9. A satellite-to-ground link processing device, characterized in that: include: An acquisition module, used to acquire visibility information between a ground station and a satellite and communication requirements between ground stations at each moment in a first time period; wherein the first time period includes a plurality of moments separated by a preset step length; A first processing module is configured to determine, according to the visibility information and the communication demand at a first moment, a first satellite-to-ground link with the smallest delay between ground station pairs with communication demand; wherein the first moment is one of the multiple moments; a second processing module, configured to determine, if the communication demand does not change at a second moment, a second satellite-to-ground link having the smallest delay between ground station pairs having communication demand at the second moment according to the first satellite-to-ground link; wherein the second moment is one of the multiple moments, and the second moment is after the first moment; A third processing module is configured to determine the second satellite-to-ground link according to the visibility information and the communication demand at the second moment if the communication demand at the second moment changes; The visibility information includes: the visibility relationship between each ground station and each satellite at each time, and / or the remaining visibility duration between each ground station and each satellite at each time; The visibility relationship includes whether the satellite is visible or invisible to the ground station; The first processing module comprises: A third processing submodule is used to determine, for each ground station, a set of target satellites whose remaining visibility duration exceeds a preset threshold according to the visibility information at the first moment; A fourth processing submodule is used to determine, for each ground station, a first target satellite in the target satellite set; wherein the first target satellite is a satellite with the smallest delay between ground stations with communication requirements; The fifth processing submodule is used to determine the first satellite-to-ground link according to the first target satellite of each ground station.

10. A communication device comprising: A transceiver, a processor, a memory, and a program or instruction stored in the memory and executable on the processor; wherein the processor implements the steps in the satellite-to-ground link processing method as described in any one of claims 1 to 8 when executing the program or instruction.

11. A readable storage medium having a program or instruction stored thereon, characterized in that: When the program or instruction is executed by a processor, the steps in the satellite-to-ground link processing method according to any one of claims 1 to 8 are implemented.

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