Path local updating method and system for large-scale low-orbit constellation

Abstract

The invention provides a local path updating method and system for a large-scale low-orbit constellation. The method comprises the following steps: carrying out system modeling on a low-orbit constellation to obtain a constellation model and end-to-end time delay problem description; based on the constellation model and the end-to-end time delay problem description, providing a path real-time dynamic local updating strategy which is used for performing local path optimization of a data packet transmission path; and optimizing and updating a local path in a data packet transmission path of the low-orbit constellation through the path real-time dynamic local updating strategy. According to the invention, the local path in the data packet transmission path is optimized and updated, so that the problem that the end-to-end delay is increased due to the fact that the data packet transmission path runs along with a large-scale constellation is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-orbit satellite network path planning, and in particular to a method and system for local path updating for a large-scale low-orbit constellation, as well as a corresponding computer terminal and computer-readable storage medium. Background Art

[0002] Low Earth Orbit (LEO) satellite networks have the characteristics of cost-effectiveness, low propagation delay, and low path loss, and have received considerable attention in the development of global informatization. In recent years, the development of LEO satellite Internet has been rapid. In order to meet the growing demand for large capacity of services, satellite Internet mostly adopts large-scale LEO satellite networking, among which the typical ones include Starlink constellation, OneWeb constellation, GW-2 constellation, etc. Among them, China Star Network's GW-2 constellation is expected to consist of more than 6,000 satellites to provide broadband access and information services. The high dynamics, long propagation delay, and rapid topology changes of large-scale LEO satellite networks have brought new challenges to the routing algorithm of the constellation. End-to-end delay is an important indicator for measuring routing algorithms. How to reduce end-to-end delay has been a hot topic for researchers in recent years.

[0003] End-to-end latency is a key metric affecting data transmission on ground terminals using satellite networks. Reducing it can improve the end-user experience. Existing strategies for reducing end-to-end latency, both domestically and internationally, often rely on selecting the shortest end-to-end path or the path with the fewest end-to-end hops. These approaches, when applied to large-scale LEO constellations, present the following challenges: the shortest path does not necessarily have the lowest end-to-end latency; nor does the path with the fewest hops necessarily have the lowest end-to-end latency. Furthermore, the topology of large-scale LEO constellations changes rapidly, and existing methods for calculating the shortest end-to-end latency path suffer from slow path updates and high update overhead. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a method and system for local path updating for a large-scale low-orbit constellation, and also provides a corresponding computer terminal and computer-readable storage medium.

[0005] According to one aspect of the present invention, a method for local path updating for a large-scale low-orbit constellation is provided, comprising:

[0006] Conduct system modeling of the low-orbit constellation to obtain a constellation model and end-to-end delay problem description;

[0007] Based on the constellation model and the description of the end-to-end delay problem, a real-time dynamic local path update strategy is provided, which is used to perform local path optimization of the data packet transmission path;

[0008] The local path in the data packet transmission path of the low earth orbit constellation is optimized and updated by using the real-time dynamic local update strategy of the path.

[0009] Preferably, performing system modeling on the low-orbit constellation includes:

[0010] Assume that the low-orbit constellation consists of multiple sub-constellations with different orbital inclinations; define the low-orbit constellation as an undirected graph G = (V, E), where V is a satellite node and n is the orbit number, m is the satellite number in the orbit, and there are a total of tracks, each track has Satellites, where the satellite number starts from the satellite in the sub-constellation with the smallest orbital inclination; E is the inter-satellite link in the constellation; the ground station is defined as ES i , i is the ground station number, ground station ES i The constellation is accessed through the ground-satellite link, and the ground stations connected to different satellite nodes are connected through the inter-satellite link E relay; in the current data packet transmission path, let the satellite v n,m The next hop satellite is The next hop satellite of the next hop is denoted as And so on;

[0011] Provides a rule for establishing an intersatellite link; wherein, satellite v n,m The intersatellite link established with the same orbit satellite is fixed, and the satellite v n,m Intersatellite links between satellites in different orbits are based on the satellite v n,m The communication distance is determined;

[0012] Defines the end-to-end delay between two ground stations.

[0013] Preferably, the establishment rules of the intersatellite link include:

[0014] Satellite v n,m The intersatellite link established with the satellite in the same orbit is a fixed intersatellite link;

[0015] Satellite v n,m The intersatellite link established with a satellite in a different orbit is set up in the following way:

[0016] Assume satellite v n,m The link distance is Dist com , different orbit satellite v n1,m1 With satellite v n,m The distance between During the satellite operation cycle, if any time is given, it always satisfies Then satellite v n1,m1 With satellite v n,mEstablish a fixed intersatellite link between them; if any time is given, sometimes Sometimes satisfied Then satellite v n1,m1 With satellite v n,m Establish a temporary intersatellite link between them; if any time is given, it always satisfies Then satellite v n1,m1 With satellite v n,m No intersatellite links can be established between them.

[0017] Preferably, for a given time t, the different orbit satellite v n1,m1 With satellite v n,m The distance between Calculated in the following way:

[0018]

[0019] Loc n,m,t =[x n,m,t ,y n,m,t ,z n,m,t ]

[0020] Loc n1,m1,t =[x n1,m1,t ,y n1,m1,t ,z n1,m1,t ] (1)

[0021] Among them, Loc n,m,t and Loc n1,m1,t Satellite v n,m and satellite v n1,m1 Coordinate information at time t;

[0022] By using formula (1), the distance between two adjacent satellites on the same orbit in each sub-constellation is calculated as the communication distance Dist of each satellite. com .

[0023] Preferably, the defining the end-to-end delay between two ground stations comprises:

[0024] Assume that the end-to-end delay between ground station ES1 and ground station ES2 is

[0025]

[0026] in, is the point-to-point delay between two satellites on the path between ground station ES1 and ground station ES2, Satellite v n,m To satellite v n1,m1 The transmission delay, Satellite v n,mTo satellite v n1,m1 The propagation delay of Satellite v n,m The processing delay of the data packet, Satellite v n,m The length of the data packet, Satellite v n,m The transmission rate, Satellite v n,m To satellite v n1,m1 The straight-line distance between them is c, which is the speed of light.

[0027] Preferably, the path real-time dynamic local update strategy includes:

[0028] Satellite v n,m Calculate satellite v separately n,m to satellite Delay and satellite to satellite Delay Get the sum of the two delays

[0029] Satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between

[0030] According to satellite v n,m With satellites that can establish intersatellite links v n1,m1 The straight-line distance between them is used to calculate the satellite v n,m To a satellite that can establish an intersatellite link v n1,m1 Delay

[0031] Delay and delay For comparison, if Then satellite v n,m Do not use satellite v n1,m1 As the pre-selected satellite for the next hop in the data transmission process, otherwise, satellite v n,m Satellite v n1,m1 As a pre-selected satellite for the next hop;

[0032] Satellite v n,m Send request data to the pre-selected satellite via the intersatellite link, wherein the request data includes satellite v n,m The next hop satellite of the next hop in the current path address;

[0033] Receive the pre-selected satellites of the requested data and calculate the pre-selected satellite to satellite Delay And delay The value is sent back to the satellite as the response data n,m ;

[0034] Satellite v n,m The delay in sending back the pre-selected satellite and delay Add them together to get satellite v n,m From pre-selected satellite to satellite New delay if Then satellite v n,m Use the pre-selected satellite as the next-hop candidate satellite;

[0035] Satellite v n,m Among all the candidate satellites, select Delay The satellite with the smallest value of is used as the new next-hop satellite, that is, the original transmission path is changed from Replace with where v' n2,m2 Complete local path optimization for the new next-hop satellite.

[0036] Preferably, the satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between:

[0037] Determine the probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 ;

[0038] Satellite v n,m Calculate the latitude and longitude information of itself at time t and the satellite v with which it has the probability of establishing an intersatellite link n1,m1 The latitude and longitude information;

[0039] Using the obtained latitude and longitude information and satellite altitude data, calculate the satellite v n,m With satellite v n1,m1 The straight-line distance between the time t

[0040]

[0041] Among them, i,Ω,e,ω,a,M0 are the six orbital numbers, is the satellite v at time t n,m Longitude, is the satellite v at time t n,m Latitude, P n,m (·) is the satellite v calculated by combining the six orbital elements with the time t n,m The latitude and longitude function, is the satellite v at time t n1,m1Longitude, is the satellite v at time t n1,m1 Latitude, P n1,m1 (·) is the satellite v calculated by combining the six orbital elements with the time t n1,m1 The longitude and latitude function, f is the function used to complete the conversion of longitude and latitude and altitude to three-dimensional coordinates.

[0042] Preferably, it also includes:

[0043] The operating period T of the low-orbit constellation is divided into N time slots, and the length of each time slot is According to the simulation results of STK, at any time slot, satellite v n,m Only the longitude and latitude information of satellites with the probability of establishing an intersatellite link in this time slot is calculated.

[0044] Preferably, the determination is likely to be related to satellite v n,m Satellite v that establishes an intersatellite link n1,m1 ,include:

[0045] Use Satellite Tool Kit (STK) to simulate a low-orbit constellation operation cycle and compare the number of satellites that can be connected to the satellite v in this cycle. n,m The six orbital numbers of the satellite that establishes the intersatellite link are stored in the satellite v n,m In memory, get the probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 .

[0046] Preferably, it also includes any one or more of the following:

[0047] -When satellite v n,m The next hop is satellite Become a satellite v' n2,m2 Afterwards, the satellite v n,m Satellite in the routing table entry Synchronous modification to satellite v' n2,m2 , at the same time, the satellite v' n2,m2 The next hop information in the command is changed to satellite. In satellite After that, the data packet continues to be transmitted along the original path to the destination node;

[0048] -When any one or more of the following special circumstances occur, perform the following operations:

[0049] The pre-selected satellites are empty sets, that is, in the satellite v n,m There are no satellites that can directly establish intersatellite links that meet the requirements of Satellite, satellite v n,m Continue to transmit data along the original path;

[0050] The candidate satellites are an empty set, that is, there is no delay that satisfies the pre-selected satellites. Satellite, satellite v n,m Continue to transmit data along the original path;

[0051] The pre-selected satellites and the candidate satellites are not empty sets, and the minimum delay is selected among the candidate satellites. The value of satellite v' n2,m2 For satellite That is, satellite v' n2,m2 With satellite For the same satellite, satellite v n,m Determine whether it can communicate with the satellite Directly establish an intersatellite link, if the satellite v n,m Can communicate directly with satellite To establish an intersatellite link, the satellite v n,m Change the next hop to satellite At this time, the number of routing hops in the path will be reduced by one hop.

[0052] According to another aspect of the present invention, a path local update system for a large-scale low-orbit constellation is provided, characterized by comprising:

[0053] System modeling module, which is used to perform system modeling of the low-orbit constellation and obtain the constellation model and end-to-end delay problem description;

[0054] Path update strategy design module, which provides a real-time dynamic local update strategy for paths based on the established constellation model and end-to-end delay problem description;

[0055] A path optimization and updating module optimizes and updates a local path in the data packet transmission path of the low-orbit constellation through the real-time dynamic local update strategy of the path.

[0056] According to a third aspect of the present invention, a computer terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the terminal can be used to execute any one of the methods described above in the present invention, or to execute the system described above in the present invention.

[0057] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, it can be used to perform any of the methods described above in the present invention, or to run the system described above in the present invention.

[0058] Due to the adoption of the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0059] The path local update method and system for large-scale low-orbit constellations provided by the present invention establish a model for the inter-satellite links of large-scale LEO constellations, which can effectively and quickly determine the communication range of each satellite.

[0060] The path local update method and system for large-scale low-orbit constellations provided by the present invention can effectively determine the set of satellites that have the probability of establishing an inter-satellite link with any specific satellite in the constellation by adopting STK simulation and time slot division, thereby effectively reducing the calculation amount of the determined satellite.

[0061] The present invention provides a local path update method and system for large-scale low-orbit Earth orbit constellations. Based on the six orbital elements, satellites can calculate the positions of satellites with which they have a probability of establishing an inter-satellite link, and further calculate the distances between them. This lack of interaction effectively reduces inter-satellite link overhead.

[0062] The local path update method and system for large-scale low-orbit constellations provided by the present invention can effectively determine the pre-selected satellite by comparing the delay from any satellite in the current data transmission path to the next hop with the delay relationship to other satellites within the communication range.

[0063] The present invention provides a local path update method and system for large-scale low-orbit Earth orbit constellations. This method uses a hybrid approach of calculating satellite position information and exchanging information. It calculates the time delay for any satellite in the path to reach the next-hop satellite via a preselected satellite. This delay includes calculation delay, transmission delay, and propagation delay. Based on this delay, alternative satellites can be identified.

[0064] The present invention provides a method and system for localized path updates for large-scale LEO constellations. This is the first application of a localized path optimization strategy in large-scale LEO constellations. This strategy addresses the potential increase in end-to-end latency associated with existing data packet transmission paths as the constellation operates. In the context of large-scale LEO constellations, localized path optimization reduces the overhead and latency associated with path updates compared to existing routing strategies. Localized path optimization also maintains the transmission of data packets by other satellites along the path. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0066] Figure 1 This is a workflow diagram of a path local update method for large-scale low-orbit constellations in a preferred embodiment of the present invention.

[0067] Figure 2The figure is a schematic diagram of the GW-2 constellation topology structure established in a specific application example of the present invention.

[0068] Figure 3 is v in different inclination sub-constellations in a specific application example of the present invention n,m A schematic diagram showing the change in the number of intersatellite links over time can be established.

[0069] Figure 4 Each time slot v in a specific application example of the present invention 1,1 Schematic diagram showing the number of satellites that need to be calculated with the probability of establishing an intersatellite link.

[0070] Figure 5 The figure is a schematic diagram of the request data format in a specific application example of the present invention.

[0071] Figure 6 Satellite v in a specific application example of the present invention n,m With satellite v n1,m1 Interaction diagram.

[0072] Figure 7 The figure is a schematic diagram of the change of the data packet transmission path after local path optimization in a specific application example of the present invention.

[0073] Figure 8 FIG1 is a schematic diagram of the component modules of a path local update system for large-scale low-orbit constellations in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0074] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process. It should be noted that those skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention.

[0075] An embodiment of the present invention provides a real-time dynamic local path update method for reducing end-to-end latency in large-scale low-Earth orbit (LEO) constellations. This method addresses the problem of gradually increasing end-to-end latency in large-scale LEO constellations as the constellation operates. Based on the predictable nature of satellite position information, a real-time path dynamics local update (RPDLU) strategy is proposed. By optimizing and updating local paths in the data packet transmission path, this method effectively addresses the problem of increased end-to-end latency in the data packet transmission path as the large-scale constellation operates.

[0076] Specifically, if Figure 1 As shown, the path local update method for a large-scale low-orbit constellation provided in this embodiment may include the following operations:

[0077] S1, perform system modeling on the low-orbit constellation to obtain the constellation model and end-to-end delay problem description;

[0078] S2, based on the established constellation model and end-to-end delay problem description, provides a real-time dynamic local path update strategy for local path optimization of the data packet transmission path;

[0079] S3 optimizes and updates the local paths in the data packet transmission paths of the low-orbit constellation through the real-time dynamic local update strategy of the paths.

[0080] In some preferred embodiments, the above S1, performing system modeling on the low-orbit constellation, may further include the following operations:

[0081] S11, assume that the low-orbit constellation consists of multiple sub-constellations with different orbital inclinations; define the low-orbit constellation as an undirected graph G = (V, E), where V is a satellite node, and define n is the orbit number, m is the satellite number in the orbit, and there are a total of tracks, each track has Satellites, where the satellite number starts from the satellite in the sub-constellation with the smallest orbital inclination; E is the inter-satellite link in the constellation; the ground station is defined as ES i , i is the ground station number, ground station ES i The constellation is accessed through the ground-satellite link, and the ground stations connected to different satellite nodes are connected through the inter-satellite link E relay; in the current data packet transmission path, let the satellite v n,m The next hop satellite is The next hop satellite of the next hop is denoted as And so on;

[0082] S12, provides a rule for establishing an intersatellite link; wherein, satellite v n,m The intersatellite link established with the same orbit satellite is fixed, and the satellite v n,m Intersatellite links between satellites in different orbits are based on the satellite v n,m The communication distance is determined;

[0083] S13 defines the end-to-end delay between two ground stations.

[0084] In some preferred embodiments, the above-mentioned S12, i.e., rules for establishing an intersatellite link, may further include the following operations:

[0085] S121, satellite v n,m The intersatellite link established with the satellite in the same orbit is a fixed intersatellite link;

[0086] S122, satellite v n,mThe intersatellite link established with a satellite in a different orbit is set up in the following way:

[0087] Assume satellite v n,m The link distance is Dist com , different orbit satellite v n1,m1 With satellite v n,m The distance between During the satellite operation cycle, if any time is given, it always satisfies Then satellite v n1,m1 With satellite v n,m Establish a fixed intersatellite link between them; if any time is given, sometimes Sometimes satisfied Then satellite v n1,m1 With satellite v n,m Establish a temporary intersatellite link between them; if any time is given, it always satisfies Then satellite v n1,m1 With satellite v n,m No intersatellite links can be established between them.

[0088] In some preferred embodiments, the above S122, for a given time t, the different orbit satellite v n1,m1 With satellite v n,m The distance between It can also be further calculated in the following way:

[0089]

[0090] Loc n,m,t =[x n,m,t ,y n,m,t ,z n,m,t ]

[0091] Loc n1,m1,t =[x n1,m1,t ,y n1,m1,t ,z n1,m1,t ] (1)

[0092] Among them, Loc n,m,t and Loc n1,m1,t Satellite v n,m and v n1,m1 Coordinate information at time t;

[0093] By using formula (1), the distance between two adjacent satellites on the same orbit in each sub-constellation can be calculated as the communication distance Dist of each satellite. com .

[0094] In some preferred embodiments, the above S13, defining the end-to-end delay between two ground stations, may further include the following operations:

[0095] Assume that the end-to-end delay between ground station ES1 and ground station ES2 is

[0096]

[0097] in, is the point-to-point delay between two satellites on the path between ground station ES1 and ground station ES2, Satellite v n,m To satellite v n1,m1 The transmission delay, Satellite v n,m To satellite v n1,m1 The propagation delay of Satellite v n,m The processing delay of the data packet, Satellite v n,m The length of the data packet, Satellite v n,m The transmission rate, Satellite v n,m To satellite v n1,m1 The straight-line distance between them, c is the speed of light.

[0098] In some preferred embodiments, the above S2 provides a path real-time dynamic local update strategy based on the established constellation model and the description of the end-to-end delay problem, and may further include:

[0099] S21, satellite v n,m Calculate satellite v separately n,m to satellite Delay and satellite to satellite Delay Get the sum of the two delays

[0100] S22, satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between

[0101] S23, according to satellite v n,m With satellites that can establish intersatellite links v n1,m1 The straight-line distance between them is used to calculate the satellite v n,m To a satellite that can establish an intersatellite link v n1,m1 Delay

[0102] S24, delay and delay For comparison, if Then satellite v n,m Do not use satellite v n1,m1 As the pre-selected satellite for the next hop in the data transmission process, otherwise, satellite v n,m Satellite v n1,m1 As a pre-selected satellite for the next hop;

[0103] S25, Satellite v n,m Send request data to the pre-selected satellite via the intersatellite link. The request data contains the satellite v n,m The next hop satellite of the next hop in the current path address;

[0104] S26, receiving the pre-selected satellite of the requested data, and calculating the pre-selected satellite to satellite Delay And delay The value is sent back to the satellite as the response data n,m ;

[0105] S27, Satellite V n,m The delay in sending back the pre-selected satellite and delay Add them together to get satellite v n,m From pre-selected satellite to satellite New delay if Then satellite v n,m Use the pre-selected satellite as the next-hop candidate satellite;

[0106] S28, Satellite V n,m Among all the candidate satellites, select Delay The satellite with the smallest value of is used as the new next-hop satellite, that is, the original transmission path is changed from Replace with where v' n2,m2 Complete local path optimization for the new next-hop satellite.

[0107] In some preferred implementations, the real-time dynamic local update strategy for paths may further include the following operations:

[0108] S29, when satellite v n,m The next hop is satellite Become a satellite v' n2,m2 Afterwards, the satellite v n,m Satellite in the routing table entry Synchronous modification to satellite v' n2,m2 , at the same time, the satellite v' n2,m2 The next hop information in the command is changed to satellite. In satellite Afterwards, the data packet continues to be transmitted along the original path to the destination node.

[0109] In some preferred implementations, the real-time dynamic local update strategy for paths may further include the following operations:

[0110] S210: When any one or more of the following special circumstances occur, perform the following operations:

[0111] S2101, the pre-selected satellite is an empty set, that is, in the satellite v n,m There are no satellites that can directly establish intersatellite links that meet the requirements of Satellite, satellite v n,m Continue to transmit data along the original path;

[0112] S2102, the candidate satellites are empty, that is, there is no delay that satisfies the pre-selected satellites. Satellite, satellite v n,m Continue to transmit data along the original path;

[0113] S2103: Both the pre-selected satellite and the candidate satellite are not empty sets, and the minimum delay is selected from the candidate satellites. The value of satellite v' n2,m2 For satellite That is, satellite v' n2,m2 With satellite For the same satellite, satellite v n,m Determine whether it can communicate with the satellite Directly establish an intersatellite link, if the satellite v n,m Can communicate directly with satellite To establish an intersatellite link, the satellite v n,m Change the next hop to satellite At this time, the number of routing hops in the path will be reduced by one hop.

[0114] In some preferred embodiments, the above S22, satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between them can further include the following operations:

[0115] S221, determine the probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 ;

[0116] S222, satellite v n,m Calculate the latitude and longitude information of itself at time t and the satellite v with which it has the probability of establishing an intersatellite link n1,m1 The latitude and longitude information;

[0117] S223, using the obtained latitude and longitude information and satellite altitude data, calculate the satellite vn,m With satellite v n1,m1 The straight-line distance between the time t

[0118]

[0119] Among them, i,Ω,e,ω,a,M0 are the six orbital numbers, is the satellite v at time t n,m Longitude, is the satellite v at time t n,m Latitude, P n,m (·) is the satellite v calculated by combining the six orbital elements with the time t n,m The latitude and longitude function, is the satellite v at time t n1,m1 Longitude, is the satellite v at time t n1,m1 Latitude, P n1,m1 (·) is the satellite v calculated by combining the six orbital elements with the time t n1,m1 The longitude and latitude function, f is the function used to complete the conversion of longitude and latitude and altitude to three-dimensional coordinates.

[0120] In some preferred embodiments, the above S22, satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between them can further include the following operations:

[0121] The operating period T of the low-orbit constellation is divided into N time slots, and the length of each time slot is According to the simulation results of STK, at any time slot, satellite v n,m Only the longitude and latitude information of satellites with the probability of establishing an intersatellite link in this time slot is calculated.

[0122] In some preferred embodiments, the above S221 determines that there is a probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 , and can further include the following operations:

[0123] Use Satellite Tool Kit (STK) to simulate a low-orbit constellation operation cycle and compare the number of satellites that can be connected to the satellite v in this cycle. n,m The six orbital numbers of the satellite that establishes the intersatellite link are stored in the satellite v n,m In memory, get the probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 .

[0124] The technical solution provided by the above embodiment of the present invention is further described in detail below with reference to a specific application example.

[0125] In this specific application example, the China Star Network GW-2 constellation is used as the application scenario. First, the system is modeled and the problem is defined. Then, a real-time dynamic local update strategy for the path is designed and applied. Finally, the real-time dynamic local update strategy for the path is analyzed. The specific operations are as follows:

[0126] 1. System Model and Problem Definition

[0127] Establish large-scale satellite topology and inter-satellite link connection models.

[0128] 1. System Modeling

[0129] (1) Constructing a constellation model

[0130] The GW-2 constellation is one of the hot topics in large-scale constellation research in recent years, and the GW-2 constellation is planned to carry intersatellite links. Therefore, in this specific application example, the GW-2 constellation is used as the modeling object, and the relevant parameters of the GW-2 constellation are shown in Table 1. The constructed GW-2 constellation topology is as follows Figure 2 shown.

[0131] Table 1 Constellation parameters

[0132]

[0133] As shown in Table 1, the GW-2 constellation contains four walker sub-constellations with orbital inclinations of 30°, 40°, 50°, and 60°, respectively. The satellite altitude is 1145 km. Each walker sub-constellation contains 36 orbits, each orbit contains 48 satellites, and the orbital phase factor is set to 2.

[0134] The GW-2 constellation is defined as an undirected graph G = (V, E), where V is a satellite node and n is the orbit number, m is the satellite number in the orbit, and there are a total of tracks, each track has Satellites. Satellite numbers are counted starting from the satellite with the smallest orbital inclination. For example, in a 30° inclination sub-constellation, the mth satellite in the nth orbit is denoted as v n,m In the 40° inclination sub-constellation, the m1th satellite in the n1th orbit is denoted as v 48+n1,m1 , where 48 is the total number of orbits in the 30° inclination sub-constellation. Similarly, the m2th satellite in the n2th orbit in the 50° inclination sub-constellation is denoted as v 96+n2,m2 E is the intersatellite link in the constellation. The ground station is defined as ES i , i is the ground station number. The ground station is connected to the constellation through the Earth-Satellite Link (ESL). a , ESb Intersatellite link relay is used for connection. In the current data packet transmission path, satellite v n,m The next hop satellite is denoted as The next hop satellite of the next hop is denoted as

[0135] (2) ISL establishment rules

[0136] The intersatellite links of the GW-2 constellation are divided into two categories: temporary intersatellite links and fixed intersatellite links. n,m The intersatellite link established with the same orbit satellite is fixed. Whether the intersatellite link established with the satellite in a different orbit is fixed depends on v n,m Communication distance. Set v n,m The link distance is Dist com , satellite v n1,m1 With v n,m The distance between them is defined as During the satellite operation cycle, if any time is given, it always satisfies Then v n1,m1 With v n,m The fixed intersatellite link is established between them. If any time is given, sometimes sometimes Then v n1,m1 With v n,m A temporary intersatellite link is established between them. If any time is given, it always satisfies Then v n1,m1 With v n,m No intersatellite link can be established between them. In the GW-2 constellation, at a given time t, the distance between any two satellites is calculated as follows:

[0137]

[0138] Loc n,m,t =[x n,m,t ,y n,m,t ,z n,m,t ]

[0139] Loc n1,m1,t =[x n1,m1,t ,y n1,m1,t ,z n1,m1,t ] (1)

[0140] Among them, Loc n,m,t and Loc n1,m1,t Satellite v n,m and v n1,m1The coordinate information at time t can be calculated by the six orbital numbers. The distance between two adjacent satellites on the same orbit in the sub-constellations with inclinations of 30°, 40°, 50°, and 60° is calculated by formula (1), which is 1311.40 km. This distance value can also be directly exported using the Satellite Tool Kit (STK) platform. In order to simplify the inter-satellite link modeling, the communication distance of each satellite in this specific application example is set to 1312 km, that is, Dist com = 1312KM. The purpose of this setting is to ensure that any given satellite can establish a fixed intersatellite link with only two other satellites in the same orbit. n,m For example, in an orbital period T:

[0141]

[0142] Where R is the radius of the Earth, G is the gravitational constant, and M is the mass of the Earth. n,m In sub-constellations with different orbital inclinations, the number of inter-satellite links that can be established changes with time as follows: Figure 3 shown.

[0143] Depend on Figure 3 It can be seen that when v n,m For satellites with a medium inclination of 30°, the average number of intersatellite links that can be established is about 65. n,m When the satellites are of 40° inclination, the average number of intersatellite links that can be established is about 65. n,m For satellites with a medium inclination of 50°, the average number of intersatellite links that can be established is about 60. n,m For satellites with a medium inclination angle of 60°, the average number of inter-satellite links that can be established is about 54.

[0144] 2. Problem Definition

[0145] The real-time dynamic local update method for paths that reduce end-to-end delay proposed in this specific application example mainly solves the problem that the path selected by the existing large-scale LEO constellation path selection method is not the real-time shortest end-to-end delay path. The current path selection method is to calculate the shortest end-to-end transmission path for a data packet at a certain moment, but the high dynamics of large-scale LEO constellations makes the "shortest" end-to-end transmission path become non-optimal as the constellation operates. If the transmission path of the data packet is recalculated from the source end, it will cause large computational overhead and delay, so a real-time dynamic local update strategy for the path is proposed in this specific application example. The end-to-end delay between ground station ES1 and ground station ES2 is defined as

[0146]

[0147] in, is the point-to-point delay between two satellites on the path from ES1 to ES2, Satellite v n,m To satellite v n1,m1 The transmission delay, Satellite v n,m To satellite v n1,m1 The propagation delay of Satellite v n,m The processing delay of the data packet, v n,m The length of the data packet, Satellite v n,m The transmission rate, Satellite v n,m to v n1,m1 where c is the speed of light. Since this application example is specific to satellite networks, the latency from the ground station to the satellite and the download latency from the satellite to the ground station are not considered.

[0148] 2. Design and Application of Path Real-time Dynamic Local Update (RPDLU) Strategy

[0149] The RPDLU policy execution process is as follows:

[0150] Step 1, v n,m Calculated to Delay Satellite v n,m arrive Delay and arrive Latency The sum of

[0151] Step 2, v n,m Calculate the satellite coordinates that can establish intersatellite links. The number of intersatellite links that can be established changes with time as follows: Figure 3 As shown;

[0152] To reduce the cost of intersatellite links, v n,m The satellite coordinates of the satellite with the probability of establishing an intersatellite link are calculated by calculating the six orbital numbers of the surrounding satellites, and v is calculated by the coordinates. n,m The straight-line distance to a satellite with which an intersatellite link can be established. The calculation of coordinates and distance is achieved through the following two steps:

[0153] Step 2.1, first determine which satellites have a probability of being with satellite v n,mEstablish intersatellite links. This judgment can be made by using the Satellite Tool Kit (STK) simulation method. In STK, simulate the GW-2 constellation to run a cycle and compare the satellites that can communicate with v n,m The six orbital numbers of the satellites that establish intersatellite links are stored in v n,m In memory. This strategy can reduce v n,m Storage space and computational complexity. If no simulation is performed, all six satellite orbit numbers in the GW-2 constellation need to be stored in v n,m Then v n,m Then traverse all satellites and calculate the position information of these satellites, and use the method simulated by STK, v n,m It is only necessary to calculate the position information of the satellites that have the probability of establishing intersatellite links in the entire cycle. For example, in GW-2, satellite v 1,1 , without STK simulation, v 1,1 It is necessary to calculate the positions of the other 6911 satellites in the constellation. After using STK simulation, at any time, v 1,1 Only the positions of 448 satellites in the constellation need to be calculated. This computational effort will be further optimized in the next step.

[0154] Step 2.2, v n,m The latitude and longitude information of the satellite at time t and the probability of establishing an intersatellite link are calculated by the following formula: n1,m1 The latitude and longitude information of the satellite is calculated by the latitude and longitude and the satellite altitude data. n,m With satellite v n1,m1 The straight-line distance between the time t The f function completes the conversion of latitude, longitude and altitude to three-dimensional coordinates, and after conversion, it is completed by formula 1 Calculation of the value. Where i, Ω, e, ω, a, M0 are the six orbital numbers.

[0155]

[0156] To further reduce v n,m The computational cost is calculated by using the time slot concept and dividing the GW-2 operation period T into N time slots. The length of each time slot is According to the simulation results of STK, at any time slot, v n,m Only the positions of satellites that have the probability of establishing an intersatellite link in this time slot are calculated. Satellite v n,m The amount of calculation is determined by the value of N. When N=1, v n,m The computational complexity is the largest because v n,m To calculate the satellite positions of all satellites that have the probability of establishing intersatellite links in the entire period. For the GW-2 constellation, when each time slot is defined as 20s, it is divided into time slots, each time slot v1,1 It is necessary to calculate the change of the number of satellites with the probability of establishing intersatellite links over time slots, such as Figure 4 As shown, compared with the calculation of 448 satellite positions, the use of 20s time slot makes each satellite v 1,1 At most, only 83 satellite positions need to be calculated. In summary, STK simulation and time slot division can effectively reduce the amount of satellite calculations.

[0157] Step 3, v n,m Calculate the distance to the satellite v that can establish an intersatellite link by the distance to the satellite that can establish an intersatellite link n1,m1 Delay The distance calculation method is shown in formula (3). It includes propagation delay, queuing delay and computation delay. The calculation formula is shown in formula (2).

[0158] Step 4, v n,m Calculated to Delay The calculation method is the same as step 3, and this delay is combined with For comparison, if Then v n,m Do not v n1,m1 As the pre-selected satellite for the next hop in the data transmission process, otherwise, v n,m V n1,m1 The satellite preselected as the next hop.

[0159] Step 5, v n,m Send the request data to the pre-selected satellite via the intersatellite link, set v n1,m1 For any of the pre-selected satellites, the request data contains v n,m The next hop satellite of the next hop in the current path The request data format is as follows: Figure 5 As shown:

[0160] Step 6: Receive the requested data n1,m1 , calculate the satellite using the same calculation method as step 3 Delay and will The value is sent back to v as the response data n,m The interaction diagram between step 5 and step 6 is as follows: Figure 6 shown.

[0161] Step 7, v n,m V n1,m1 The delay value sent back With v n,m Calculate to v n1,m1 The delay value Add them together to get v n,mAfter v n1,m1 to satellite New delay value if v n,m Then the satellite v n1,m1 As an alternative next-hop satellite. Use v n2,m2 As one of the alternative satellites.

[0162] Step 8, v n,m Among all the satellites available, select The satellite with the smallest value is used as the new next hop, which means the original transmission path is changed from Replace with where v' n2,m2 The minimum delay among the alternative satellites The satellite corresponding to the value is called local path optimization. Figure 7 shown.

[0163] Step 9: This update targets some satellites in the path of a single service data transmission process. The update does not affect the normal transmission of data, such as satellite Update to v' n2,m2 Afterwards, satellite v n,m When transmitting data packets, the route will not be recalculated, so there will be no interruption in the transmission of data packets. n,m The next hop is becomes v' n2,m2 Afterwards, v n,m In the routing table entry Synchronously modified to v' n2,m2 , and v' n2,m2 The next hop in is changed to In satellite Afterwards, the data packet continues to be transmitted along the original path to the destination node.

[0164] In step 10, there are the following special cases:

[0165] 1) The pre-selected satellite is an empty set, that is, in the satellite v n,m There are no satellites that can directly establish intersatellite links that meet the requirements of satellite.

[0166] 2) The candidate satellites are empty, that is, there is no delay that satisfies the pre-selected satellites. satellite.

[0167] 3) Both the pre-selected satellites and the candidate satellites are not empty sets, select The satellite v' corresponding to the minimum value n2,m2 It's a satellite That is, satellite v'n2,m2 With satellite The scenario that satisfies this situation is as follows: Satellite v n,m With satellite During the initial communication, Not on Satellite V n,m The communication range of the satellite v n,m Able to directly Establish intersatellite link. Because the original path satellite v n,m to satellite Need to pass through satellite Complete the forwarding of data packets. It will increase processing delay, queuing delay and propagation delay, so when v n,m Can When establishing an intersatellite link directly, select v n,m and Direct communication.

[0168] 3. Analysis of Path Real-time Dynamic Local Update (RPDLU) Strategy

[0169] 1. Satellite v n,m The calculation of the position information (latitude and longitude information) and distance information (straight-line distance value) of the satellite that can establish an intersatellite link is based on the six stored orbital numbers. This step does not require interaction with satellites that have the probability of establishing an intersatellite link, reducing the bandwidth overhead of the intersatellite link. n,m When the satellite establishing the intersatellite link is selected as the pre-selected satellite, the satellite v n,m Interacting with the pre-selected satellite once completes v n,m By preselecting satellite to satellite v n,m Next hop satellite Delay Satellite v n,m According to the delay Delay in the original path The value of the relationship, select the candidate satellite, select the candidate satellite The satellite with the smallest value is taken as satellite v n,m New next hop.

[0170] 2. After the path is partially updated, the end-to-end delay will inevitably decrease. For example, the satellite v n,m The next hop satellite is updated. After the update, the data packet is in the satellite v n,m Before and Satellite The subsequent transmission path remains unchanged. Therefore, the satellite v n,m Before and Satellite The delay will not change after that, but the satellite v n,m to satellite Therefore, the end-to-end delay between the source and destination nodes is reduced. Figure 7 In the transmission path, there is only the original satellite v 2,2 Switch to satellite v 1,2 , after switching satellite v 1,1 To satellite v 2,3 If the delay is reduced, the updated delay must be smaller than the original path delay.

[0171] 3. The local path update does not affect the business data being transmitted. n,m Next-hop satellite After switching to a new satellite, it is a black box operation for other satellites in the path, that is, the switch does not affect the data transmission of other satellites in the path. The only change is the satellite v n,m The data is transmitted to the next hop, which then transmits the data to the satellite.

[0172] An embodiment of the present invention provides a path local update system for large-scale low-orbit constellations.

[0173] Specifically, if Figure 8 As shown, the path local update system for large-scale low-orbit constellations provided in this embodiment may include the following modules:

[0174] System modeling module, which is used to perform system modeling of the low-orbit constellation and obtain the constellation model and end-to-end delay problem description;

[0175] Path update strategy design module, which provides a real-time dynamic local update strategy for paths based on the established constellation model and end-to-end delay problem description;

[0176] The path optimization and update module optimizes and updates the local path in the data packet transmission path of the low-orbit constellation through a real-time dynamic local update strategy.

[0177] It should be noted that the steps in the method provided by the present invention can be implemented using corresponding modules, devices, units, etc. in the system. Those skilled in the art can refer to the technical solution of the method to implement the composition of the system, that is, the embodiments in the method can be understood as preferred examples of constructing the system, which will not be elaborated here.

[0178] An embodiment of the present invention provides a computer terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the processor can be used to execute any one of the methods described in the foregoing embodiments of the present invention, or to execute any one of the systems described in the foregoing embodiments of the present invention.

[0179] Optionally, the memory is used to store programs; the memory may include volatile memory (English: volatile memory), such as random-access memory (English: random-access memory, abbreviated: RAM), such as static random-access memory (English: static random-access memory, abbreviated: SRAM), double data rate synchronous dynamic random access memory (English: Double Data Rate Synchronous Dynamic Random Access Memory, abbreviated: DDR SDRAM), etc.; the memory may also include non-volatile memory (English: non-volatile memory), such as flash memory (English: flash memory). The memory is used to store computer programs (such as applications, functional modules, etc. that implement the above-mentioned methods), computer instructions, etc., and the above-mentioned computer programs, computer instructions, etc. can be partitioned and stored in one or more memories. In addition, the above-mentioned computer programs, computer instructions, data, etc. can be called by the processor.

[0180] The aforementioned computer programs, computer instructions, etc. may be partitioned and stored in one or more memories, and the aforementioned computer programs, computer instructions, data, etc. may be called by a processor.

[0181] The processor is configured to execute the computer program stored in the memory to implement the various steps of the method or various modules of the system involved in the above embodiments. For details, please refer to the relevant descriptions in the above method and system embodiments.

[0182] The processor and memory can be independent structures or integrated structures. When the processor and memory are independent structures, the memory and processor can be coupled via a bus.

[0183] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it can be used to execute any method of the above embodiments of the present invention, or to run any system of the above embodiments of the present invention.

[0184] The above-mentioned embodiments of the present invention provide a method and system for local path updating for large-scale low-orbit (LEO) constellations, which implement an inter-satellite link construction method for large-scale LEO constellations. By adopting the STK simulation and time slot partitioning method, the set of satellites with which any determined satellite in the constellation has a probability of establishing an inter-satellite link can be effectively determined, thereby effectively reducing the computational complexity of the determined satellite. The satellite can calculate the position (latitude and longitude information) of the satellite with which it has a probability of establishing an inter-satellite link without interaction, and then calculate the distance between the satellite and the satellite with the probability of establishing an inter-satellite link. For any satellite in the current data transmission path, by comparing the delay from the satellite to the next hop with the delay relationship to other satellites within the communication range, a pre-selected satellite can be effectively determined. A hybrid method of calculating satellite position information and one-time information interaction is used to complete the calculation of the delay for any satellite in the path to reach the next-hop satellite through the pre-selected satellite. The delay includes calculation delay, transmission delay, and propagation delay, and the candidate satellite can be confirmed based on this delay.

[0185] Matters not mentioned in the above embodiments of the present invention are well known in the art.

[0186] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A path local update method for large-scale low-orbit constellations, characterized by: include: Conduct system modeling of the low-orbit constellation to obtain a constellation model and end-to-end delay problem description; Based on the constellation model and the description of the end-to-end delay problem, a real-time dynamic local path update strategy is provided, which is used to perform local path optimization of the data packet transmission path; The local path in the data packet transmission path of the low earth orbit constellation is optimized and updated by using the real-time dynamic local update strategy of the path.

2. The path local update method for large-scale low-orbit constellations according to claim 1, characterized in that: The system modeling of the low-orbit constellation includes: Assume that the low-orbit constellation consists of multiple sub-constellations with different orbital inclinations; define the low-orbit constellation as an undirected graph G = (V, E), where V is a satellite node and n is the orbit number, m is the satellite number in the orbit, and there are a total of tracks, each track has Satellites, where the satellite number starts from the satellite in the sub-constellation with the smallest orbital inclination; E is the inter-satellite link in the constellation; the ground station is defined as ES i , i is the ground station number, ground station ES i The constellation is accessed through the ground-satellite link, and the ground stations connected to different satellite nodes are connected through the inter-satellite link E relay; in the current data packet transmission path, let the satellite v n,m The next hop satellite is The next hop satellite of the next hop is denoted as And so on; Provides a rule for establishing an intersatellite link; wherein, satellite v n,m The intersatellite link established with the same orbit satellite is fixed, and the satellite v n,m Intersatellite links between satellites in different orbits are based on the satellite v n,m The communication distance is determined; Defines the end-to-end delay between two ground stations.

3. The path local update method for large-scale low-orbit constellations according to claim 2, characterized in that: The establishment rules of the intersatellite link include: Satellite v n,m The intersatellite link established with the satellite in the same orbit is a fixed intersatellite link; Satellite v n,m The intersatellite link established with a satellite in a different orbit is set up in the following way: Assume satellite v n,m The link distance is Dist com , different orbit satellite v n1,m1 With satellite v n,m The distance between During the satellite operation cycle, if any time is given, it always satisfies Then satellite v n1,m1 With satellite v n,m Establish a fixed intersatellite link between them; if any time is given, sometimes Sometimes satisfied Then satellite v n1,m1 With satellite v n,m Establish a temporary intersatellite link between them; if any time is given, it always satisfies Then satellite v n1,m1 With satellite v n,m No intersatellite links can be established between them; among them: For a given time t, the satellite v in different orbits n1,m1 With satellite v n,m The distance between Calculated in the following way: Loc n,m,t [x n,m,t ,y n,m,t ,z n,m,t ] Loc n1,m1,t [x n1,m1,t ,y n1,m1,t ,z n1,m1,t ] (1) Among them, Loc n,m,t and Loc n1,m1,t Satellite v n,m and satellite v n1,m1 Coordinate information at time t; By using formula (1), the distance between two adjacent satellites on the same orbit in each sub-constellation is calculated as the communication distance Dist of each satellite. com .

4. The path local update method for large-scale low-orbit constellations according to claim 2, characterized in that: The definition of the end-to-end delay between two ground stations includes: Assume that the end-to-end delay between ground station ES1 and ground station ES2 is in, is the point-to-point delay between two satellites on the path between ground station ES1 and ground station ES2, Satellite v n,m To satellite v n1,m1 The transmission delay, Satellite v n,m To satellite v n1,m1 The propagation delay of Satellite v n,m The processing delay of the data packet, Satellite v n,m The length of the data packet, Satellite v n,m The transmission rate, Satellite v n,m To satellite v n1,m1 The straight-line distance between them is c, which is the speed of light.

5. The path local update method for a large-scale low-orbit constellation according to any one of claims 1 to 4, characterized in that: The path real-time dynamic local update strategy includes: Satellite v n,m Calculate satellite v separately n,m to satellite Delay and satellite to satellite Delay Get the sum of the two delays Satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between According to satellite v n,m With satellites that can establish intersatellite links v n1,m1 The straight-line distance between them is used to calculate the satellite v n,m To a satellite that can establish an intersatellite link v n1,m1 Delay Delay and delay For comparison, if Then satellite v n,m Do not use satellite v n1,m1 As the pre-selected satellite for the next hop in the data transmission process, otherwise, satellite v n,m Satellite v n1,m1 As a pre-selected satellite for the next hop; Satellite v n,m Send request data to the pre-selected satellite via the intersatellite link, wherein the request data includes satellite v n,m The next hop satellite of the next hop in the current path address; Receive the pre-selected satellites of the requested data and calculate the pre-selected satellite to satellite Delay And delay The value is sent back to the satellite as the response data n,m ; Satellite v n,m The delay in sending back the pre-selected satellite and delay Add them together to get satellite v n,m From pre-selected satellite to satellite New delay if Then satellite v n,m Use the pre-selected satellite as the next-hop candidate satellite; Satellite v n,m Among all the candidate satellites, select Delay The satellite with the smallest value of is used as the new next-hop satellite, that is, the original transmission path is changed from Replace with where v' n2,m2 Complete local path optimization for the new next-hop satellite.

6. The path local update method for large-scale low-orbit constellations according to claim 5, characterized in that: The satellite v n,m Calculate the number of satellites v that can establish intersatellite links n1,m1 The straight-line distance between: Determine the probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 ; Satellite v n,m Calculate the latitude and longitude information of itself at time t and the satellite v with which it has the probability of establishing an intersatellite link n1,m1 The latitude and longitude information; Using the obtained latitude and longitude information and satellite altitude data, calculate the satellite v n,m With satellite v n1,m1 The straight-line distance between the time t Among them, i,Ω,e,ω,a,M0 are the six orbital numbers, is the satellite v at time t n,m Longitude, is the satellite v at time t n,m Latitude, P n,m (·) is the satellite v calculated by combining the six orbital elements with the time t n,m The latitude and longitude function, is the satellite v at time t n1,m1 Longitude, is the satellite v at time t n1,m1 Latitude, P n1,m1 (·) is the satellite v calculated by combining the six orbital elements with the time t n1,m1 The longitude and latitude function, f is the function used to complete the conversion of longitude and latitude and altitude to three-dimensional coordinates.

7. The path local update method for large-scale low-orbit constellations according to claim 6, characterized in that: Also includes: The operating period T of the low-orbit constellation is divided into N time slots, and the length of each time slot is According to the simulation results of STK, at any time slot, satellite v n,m Only the longitude and latitude information of satellites with the probability of establishing an intersatellite link in this time slot is calculated.

8. The path local update method for large-scale low-orbit constellations according to claim 5, characterized in that: The determination has a probability with satellite v n,m Satellite v that establishes an intersatellite link n1,m1 ,include: Use STK to simulate the low-orbit constellation to run a cycle, and calculate the number of satellites that can be connected to the satellite v in this cycle. n,m The six orbital numbers of the satellite that establishes the intersatellite link are stored in the satellite v n,m In memory, get the probability of satellite v n,m Satellite v that establishes an intersatellite link n1,m1 .

9. The path local update method for large-scale low-orbit constellations according to claim 5, characterized in that: Also includes any one or more of the following: -When satellite v n,m The next hop is satellite Become a satellite v' n2,m2 Afterwards, the satellite v n,m Satellite in the routing table entry Synchronous modification to satellite v' n2,m2 , at the same time, the satellite v' n2,m2 The next hop information in the command is changed to satellite. In satellite After that, the data packet continues to be transmitted along the original path to the destination node; -When any one or more of the following special circumstances occur, perform the following operations: The pre-selected satellites are empty sets, that is, in the satellite v n,m There are no satellites that can directly establish intersatellite links that meet the requirements of Satellite, satellite v n,m Continue to transmit data along the original path; The candidate satellites are an empty set, that is, there is no delay that satisfies the pre-selected satellites. Satellite, satellite v n,m Continue to transmit data along the original path; The pre-selected satellites and the candidate satellites are not empty sets, and the minimum delay is selected among the candidate satellites. The value of satellite v' n2,m2 For satellite That is, satellite v' n2,m2 With satellite For the same satellite, satellite v n,m Determine whether it can communicate with the satellite Directly establish intersatellite link, if satellite v n,m Can communicate directly with satellite To establish an intersatellite link, the satellite v n,m Change the next hop to satellite At this time, the number of routing hops in the path will be reduced by one hop.

10. A path local update system for large-scale low-orbit constellations, characterized by: include: System modeling module, which is used to perform system modeling of the low-orbit constellation and obtain the constellation model and end-to-end delay problem description; Path update strategy design module, which provides a real-time dynamic local update strategy for paths based on the established constellation model and end-to-end delay problem description; A path optimization and updating module optimizes and updates a local path in the data packet transmission path of the low-orbit constellation through the real-time dynamic local update strategy of the path.

11. A computer terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When executing the computer program, the processor can be used to perform the method according to any one of claims 1 to 9, or run the system according to claim 10.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it can be used to perform the method according to any one of claims 1 to 9, or to run the system according to claim 10.

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