A method for large-scale random node loss rerouting for low-Earth orbit satellite constellations

Abstract

This invention discloses a method for replanning routes after large-scale random node loss in low-Earth orbit (LEO) satellite constellations, belonging to the field of LEO satellite constellation communication technology. This invention solves the problem of rapidly rebuilding links in a sudden large-scale random node loss event in an LEO remote sensing satellite constellation, as described in existing technologies. By performing topology analysis on the LEO communication constellation based on a Walker-Delta configuration, a multi-level hierarchy based on point distance is established. This is combined with the communication weights between nodes to perform spontaneous recursion of the damaged links, enabling the replanning and reconstruction of communication routes even in the absence of global network information after large-scale random node loss. It offers advantages such as rapid response, decentralization, and spontaneous network reorganization, providing technical support and reference for the spontaneous reconstruction of links after random node loss in large-scale LEO constellations, and solving related engineering problems.

Description

Technical Field

[0001] This invention relates to the field of low-Earth orbit (LEO) satellite constellation communication technology, specifically to a large-scale random node failure routing replanning method for LEO satellite constellations. Background Technology

[0002] With the rapid deployment of low Earth orbit (LEO) satellite constellations in global communications, the Internet of Things (IoT), and emergency communications, highly reliable routing technology under their dynamic topology has become a key challenge. Traditional satellite routing algorithms are typically based on pre-defined inter-satellite links (ISLs) and periodic topology update mechanisms, capable of handling routine satellite node switching or a small number of link failures. However, in the event of sudden events such as space debris impacts, solar storms, or human attacks, constellations may experience large-scale, clustered satellite damage (e.g., regional node failures exceeding 30%), at which point existing routing schemes face severe bottlenecks.

[0003] (1) Low convergence efficiency: Routing reconstruction based on distributed link state protocols (such as OSPF extended algorithm) relies on the flooding of the entire network topology. When nodes fail continuously on a large scale, the flooding of update messages will cause network congestion, and the convergence time will increase exponentially, which cannot meet the real-time communication requirements.

[0004] (2) Path calculation failure: When a centralized routing controller (such as a ground gateway station) is suddenly damaged, it may be unable to obtain the complete topology due to the loss of critical relay nodes, resulting in the suspension of path calculation. Even with a backup controller, the latency of topology reconstruction still far exceeds the service interruption tolerance threshold.

[0005] (3) Cascaded congestion risk: After local damage triggers traffic redirection, adjacent satellites become overloaded due to sudden load surges, causing avalanche-like network paralysis (such as satellites at the edge of "hole areas" going down due to traffic convergence). Existing load balancing algorithms lack elastic response mechanisms for extreme damage scales.

[0006] (4) Resource constraints: Onboard computing power is limited. Traditional multi-path redundancy schemes (such as the k-shortest path algorithm) have a significantly increased computational complexity when there are large-scale topology changes, exceeding the onboard processing capacity, and cannot dynamically coordinate backup paths across orbital planes.

[0007] Current technologies are based on machine learning or topology partitioning for optimized routing, but they still focus on small-scale failures or planned maintenance scenarios. Their model training relies on historical data and is difficult to adapt to unpredictable topologies with sudden large-scale damage. Meanwhile, SDN-based satellite-ground coordination solutions are limited by satellite-ground transmission latency, resulting in delayed control response in emergency scenarios.

[0008] Therefore, there is an urgent need for an efficient route replanning mechanism for extreme damage scenarios, capable of achieving sub-second topology awareness, distributed collaborative decision-making, and anti-cascading congestion control under onboard resource constraints, ensuring that the constellation maintains core service connectivity even when some functions are paralyzed. Summary of the Invention

[0009] The purpose of this invention is to provide a method for replanning routes in low-Earth orbit (LEO) satellite constellations after large-scale random node damage. Based on a Walker-Delta configuration, the method performs topology analysis on the LEO communication constellation orbit, establishes a multi-level hierarchy based on point distance, and combines the communication weights between nodes to perform spontaneous recursion of damaged links. This allows for the replanning and reconstruction of communication routes in the event of large-scale random node damage and a lack of global network information. It offers advantages such as rapid response, decentralization, and spontaneous network reorganization, providing technical support and reference for the spontaneous reconstruction of links after random node damage in large-scale LEO constellations, solving related engineering problems, and addressing the issues raised in the background section.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A method for large-scale random node loss rerouting for low-Earth orbit satellite constellations includes the following steps:

[0012] Step 1: Establish a low-Earth orbit communication satellite constellation topology model;

[0013] Step 2: Identify the communication link nodes that need to be established and construct the data packet structure for inter-node interaction;

[0014] Step 3: Calculate the possible hop count list based on the routing rules, and simplify the topology model, compressing the three-dimensional topology into a planar local topology;

[0015] Step 4: Based on the initial node, prioritize the secondary nodes;

[0016] Step 5: Calculate edge weights within nodes of the same priority level sequentially, and determine the next-hop node, including:

[0017] Based on the maximum of three levels, the weights of each hop edge within the same level are calculated sequentially. A weight estimation model for inter-satellite links is established, and the weight formula is as follows:

[0018] (1)

[0019] in, Indicates at time From satellite node To satellite node The overall weight of the links; Indicates the weighting coefficient of the bandwidth factor; Indicates the weighting coefficient of storage factors; This represents the weighting coefficient of the distance factor; This represents the actual physical distance of the inter-satellite link;

[0020] (2)

[0021] in, This represents the normalized ratio of the current link bandwidth to the maximum bandwidth. This indicates the currently available bandwidth of the current link; This represents the maximum theoretical bandwidth of the current link;

[0022] (3)

[0023] in, Indicates satellite node Metrics related to remaining storage capacity; Indicates satellite node The current used storage capacity; Indicates satellite node Total storage capacity;

[0024] If there is no suitable secondary node under the current priority level, then query the secondary nodes of the next priority level until a suitable secondary node is found or all possible nodes are completely traversed.

[0025] Step 6: Iterate through the results of the secondary node selection until a usable route is found or a result indicating that a link cannot be established is returned.

[0026] Furthermore, in step 1, a low-Earth orbit communication satellite constellation topology model is established, including:

[0027] Let the satellite's orbital altitude be Inclination angle is And all tracks are circular tracks;

[0028] Consider two satellites, A and B, located between two adjacent orbits. Let the phase difference between A and B be denoted as . ;

[0029] Since the two satellites have the same orbital period, the phase difference between their nodes remains constant. Therefore, at time t, the angle between the two satellites and the line connecting them to the Earth's center is... Represented as:

[0030] (4)

[0031] in, The phase difference between satellites A and B; The difference in longitude between the ascending nodes of the two satellites; and These are the phases of satellite nodes A and B at time t, respectively;

[0032] The phase of node B is then expressed as:

[0033] (5)

[0034] The link distance between satellites A and B is:

[0035] (6)

[0036] Among them, R E It is expressed as the average radius of the Earth.

[0037] Furthermore, after determining the link distance between satellites A and B, the following is included:

[0038] Link elevation angle from satellite A to satellite B and azimuth for:

[0039] (7)

[0040] (8)

[0041] in:

[0042] (9)

[0043] (10)

[0044] (11)

[0045] At the same time, it was concluded that The scope is:

[0046] (12)

[0047] (13).

[0048] Furthermore, after determining the link distance between satellites A and B, the following is also included:

[0049] If let Then the expressions for the link distance and pointing angle between the two satellites simplify to:

[0050] (14)

[0051] To clarify the variation of inter-satellite links with phase, further analysis of the links was conducted:

[0052] (15)

[0053] right The derivative is expressed as:

[0054] (16)

[0055] Based on the previous analysis:

[0056] (17)

[0057] Therefore, the equation for the inter-satellite link variation with phase can be derived as follows:

[0058] (18)

[0059] Obviously, by setting the above equation to 0, we can obtain the extreme case of the inter-satellite link, where:

[0060] (19)

[0061] in, It is represented as a set of integers.

[0062] Further analysis of the link includes:

[0063] Combining equations 4 and 19, we arrive at the following conclusion:

[0064] when When k is even:

[0065] (20)

[0066] (twenty one)

[0067] when When k is odd:

[0068] (twenty two)

[0069] (twenty three).

[0070] Further, in step 2, based on the construction of the inter-node interaction data packet structure, the following is included:

[0071] The TCP / IP protocol is used to complete communication between nodes;

[0072] Based on the inter-satellite network and topology model, a data packet encapsulation structure is constructed; the data packet encapsulation structure includes: packet identifier, source node satellite identifier, destination node satellite identifier, source node IP, destination node IP, packet length or multiple packet continuation identifier, packet data, and checksum.

[0073] Furthermore, in step 3, a list of possible hop counts is calculated based on routing patterns, and the topology model is simplified, compressing the three-dimensional topology into a planar local topology, including:

[0074] In the network topology, select any two nodes A and B. Calculate the hop count limit between A and B using Equations 4-23 based on their node numbers. The expression is as follows:

[0075] (twenty four)

[0076] in, and These represent the node numbers of A and B in the network, respectively.

[0077] Furthermore, after calculating the limit of the number of jumps between points A and B, it includes:

[0078] Based on the node numbers of nodes A and B, the total number of orbits, and the number of nodes on the orbital plane, the reverse links of nodes A and B are calculated, and expressed as follows:

[0079] (25)

[0080] (26)

[0081] (27)

[0082] in, This represents the total number of orbital surfaces; This represents the total number of satellite nodes on each orbital plane; This is represented by taking the outer arc in both directions, indicating a path around the outer edge of the torus in the two-dimensional topology; This is represented as moving in an outer arc in the direction of the orbital plane number and in an inner arc in the direction of the phase within the orbit; This is represented as moving in an inner arc in the direction of the orbital plane number and in an outer arc in the direction of the phase within the orbit;

[0083] By comparison Based on the above three results, the shortest hop count between nodes A and B in the local area is obtained, the logical boundaries that the shortest link may cross in the three-dimensional topology are determined, and the planar local topology is derived, simplifying the entire three-dimensional topology into a local planar topology centered on A and B.

[0084] Furthermore, in step 6, the selection results of secondary nodes are used for iterative iteration until a usable route path is found or a result indicating that a link cannot be established is returned, including:

[0085] When the current node queries a sub-node, there are two possibilities: a suitable sub-node is found, or no suitable sub-node is found after traversal.

[0086] If the current node finds a suitable secondary node, then the current node is added to the routing sequence and the list of memory nodes, and the found secondary node is set as the current node.

[0087] If no suitable secondary node is found after the current node is traversed, the current node is considered a closed node, the previous node of the current node in the routing sequence is set as the current node, and the selection of secondary nodes is performed again.

[0088] The process is repeated iteratively until a usable route is found or a result indicating that a link cannot be established is returned.

[0089] Compared with the prior art, the beneficial effects of the present invention are:

[0090] This invention, based on a Low Earth Orbit (LEO) communication constellation with a Walker-Delta configuration, performs topological analysis of the LEO constellation's orbit, establishes a multi-level hierarchy based on point-to-point distance, and combines the communication weights between nodes (i.e., the values ​​of each edge in the topology) to perform spontaneous recursion of damaged links. This enables the replanning and reconstruction of communication routes in situations where large-scale random node damage occurs and global network information is lacking. It offers advantages such as rapid response, decentralization, and spontaneous network reorganization, providing technical support and reference for the spontaneous reconstruction of links after random node damage in large-scale LEO constellations, and solving related engineering problems. Attached Figure Description

[0091] Figure 1 This is a schematic diagram of the constellation local network of the present invention;

[0092] Figure 2 This is a schematic diagram of the protocol stack structure of the network of the present invention;

[0093] Figure 3 This is a schematic diagram illustrating the priority grouping of the current node to the secondary node according to the present invention. Detailed Implementation

[0094] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0095] To address the technical problems of low convergence efficiency, path calculation failure, cascading congestion risk, and resource constraints in existing technologies, please refer to [link to relevant documentation]. Figure 1 This embodiment provides the following technical solution:

[0096] A method for large-scale random node loss rerouting for low-Earth orbit satellite constellations includes the following steps:

[0097] Step 1: Establish a low-Earth orbit communication satellite constellation topology model; including:

[0098] As can be seen from the characteristics of low-Earth orbit communication constellations, in a Walker constellation, the relative topology between any two satellites remains constant throughout the entire operation, but the physical characteristics between the two satellites will change periodically. Taking a laser link as an example, the inter-satellite link distance and laser pointing after the link is established between two satellites will change over time. The pattern of this change can be determined by the constellation parameters. Taking a Walker constellation with 1296 satellites and constellation parameters of 1296 / 72 / 1 as an example:

[0099] Let the satellite's orbital altitude be Inclination angle is And all tracks are circular tracks;

[0100] Consider two satellites, A and B, located between two adjacent orbits. Let the phase difference between A and B be denoted as . ;

[0101] Since the two satellites have the same orbital period, the phase difference between their nodes remains constant. Therefore, at time t, the angle between the two satellites and the line connecting them to the Earth's center is... Represented as:

[0102]

[0103] in, The phase difference between satellites A and B; The difference in longitude between the ascending nodes of the two satellites; and These are the phases of satellite nodes A and B at time t, respectively;

[0104] The phase of node B is then expressed as:

[0105]

[0106] The link distance between satellites A and B is:

[0107]

[0108] Among them, R E It is expressed as the average radius of the Earth;

[0109] Link elevation angle from satellite A to satellite B and azimuth for:

[0110]

[0111]

[0112] in:

[0113]

[0114]

[0115]

[0116] At the same time, it was concluded that The scope is:

[0117]

[0118]

[0119] Analysis of the formulas shows that only... The relationship between satellite nodes A and B changes over time, and also changes with the satellite's orbital period; therefore, the physical relationship between them also changes periodically with time. Furthermore, it can be seen that the inter-satellite link also changes with orbital altitude. From this perspective, it can be explained that for large-scale communication constellations, low-Earth orbit (LEO) inter-satellite links are more economical than high-Earth orbit (HEO) inter-satellite links.

[0120] If let Then the expressions for the link distance and pointing angle between the two satellites simplify to:

[0121]

[0122] At this point, the link relationship between satellites with different phases in the same orbit can be indicated. It can be seen that none of the formulas above contain time variables. This indicates that the physical characteristics of the link between any two satellite nodes in the same orbit are only related to their phase difference and do not change with time, which is consistent with expectations.

[0123] To clarify the variation of inter-satellite links with phase, further analysis of the links was conducted:

[0124]

[0125] right The derivative is expressed as:

[0126]

[0127] Based on the previous analysis:

[0128]

[0129] Therefore, the equation for the inter-satellite link variation with phase can be derived as follows:

[0130]

[0131] Obviously, by setting the above equation to 0, we can obtain the extreme case of the inter-satellite link, where:

[0132]

[0133] in, It is represented as a set of integers.

[0134] Based on the above formulas, we can conclude that:

[0135] when When k is even:

[0136]

[0137]

[0138] when When k is odd:

[0139]

[0140]

[0141] The above calculations lead to the conclusion that when k is even... At this point, the distance of the inter-satellite link is decreasing over time; when k is odd, At this time, the distance of the inter-satellite link increases with time, and its period of change is , with the phase interval between the maximum and minimum values ​​being . .

[0142] In summary, within a low Earth orbit constellation, the links between adjacent nodes within the same orbit remain stable, while the links between adjacent orbits exhibit periodic changes.

[0143] like Figure 1 As shown, in a single-layer network, since it has a stable two-dimensional rectangular grid topology, it is possible to consider using M×N type numbering based on different tracks; where m is the track surface number and n is the node number within the same track surface; for each adjacent track surface, the track numbers are adjacent and the node numbers within the track correspond.

[0144] Step 2: Identify the communication link nodes that need to be established, and construct the data packet structure for inter-node interaction; including:

[0145] The TCP / IP protocol is used to complete communication between nodes;

[0146] Based on the inter-satellite network and topology model, a data packet encapsulation structure is constructed; the data packet encapsulation structure includes: packet identifier, source node satellite identifier, destination node satellite identifier, source node IP, destination node IP, packet length or multi-packet continuation identifier, packet data, and checksum; specifically:

[0147]

[0148] Table 1. Packet Encapsulation Structure

[0149] Here, m1 and m2 represent the orbits of the nodes; n1 and n2 represent the node numbers within their respective orbits; adjacent satellite nodes periodically exchange their own information, and packet identifiers are used to distinguish signaling data packets from transmission data packets; simultaneously, a time-to-live limit is set for the packets contained in the packet identifiers to avoid circular data links during the process of decentralized routing, which would lead to a large amount of dead data in the network; the entire cluster achieves inter-satellite routing through the source node satellite identifier and the destination node satellite identifier in the packet encapsulation structure. Accordingly, based on this design, the protocol stack structure of the established network is as follows: Figure 2 As shown.

[0150] Taking the data packet from node (1,1) to node (18,10) as an example, the generated data packet would be as follows:

[0151]

[0152] Step 3: Calculate the possible hop count list based on routing patterns and simplify the topology model, compressing the three-dimensional topology into a planar local topology; including:

[0153] Analyzing the constructed 3D topology, directly mapping all nodes to a 2D planar topology cannot fully describe the routing situation of a 3D topology in a single link planning process. To represent the routing planning process of a single link in a planar topology, a 2D planar extended topology with complete nodes is constructed, transforming the optimal path problem in the 3D topology into a pathfinding problem in a 2D topology.

[0154] In the network topology, select any two nodes A and B. Calculate the hop count limit between A and B using the formula above, based on their node numbers. The expression is:

[0155]

[0156] in, and These represent the node numbers of A and B in the network, respectively;

[0157] Since the external links of nodes AB supplement the internal links of nodes AB, the reverse links of nodes AB are calculated based on the node numbers of nodes AB, the total number of tracks, and the number of nodes on the track plane. This is expressed as:

[0158]

[0159]

[0160]

[0161] in, This represents the total number of orbital surfaces; This represents the total number of satellite nodes on each orbital plane; This is represented by taking the outer arc in both directions, indicating a path around the outer edge of the torus in the two-dimensional topology; This is represented as moving in an outer arc in the direction of the orbital plane number and in an inner arc in the direction of the phase within the orbit; This is represented as moving in an inner arc in the direction of the orbital plane number and in an outer arc in the direction of the phase within the orbit;

[0162] By comparison Based on the above three results, the shortest hop count between nodes A and B in the local area is obtained, the logical boundaries that the shortest link may cross in the three-dimensional topology are determined, and the planar local topology is derived, simplifying the entire three-dimensional topology into a local planar topology centered on A and B.

[0163] Step 4: Using the initial node as the starting node, prioritize the secondary nodes; specifically: (e.g.) Figure 3 As shown, based on the positions of the starting and ending nodes, the ideal optimal number of hops between all possible secondary nodes and the ending node in the topology network is calculated; and based on the possible ideal optimal number of hops, all secondary nodes are divided into a maximum of 3 levels.

[0164] Step 5: Calculate edge weights within nodes of the same priority level sequentially, and determine the next-hop node; including:

[0165] Based on the division of up to 3 levels, the system traverses sequentially and calculates the weight of each hop edge within the same level. The weight is the single-hop cost from the current node to the next hop. In practical applications, this part can be adjusted according to the planning objectives and actual needs. This embodiment takes the bandwidth constraints of inter-satellite links, the storage constraints on satellites, and the dynamic topology changes of satellite networks caused by changes in satellite fixed links as examples to give a delay calculation model.

[0166] Based on three points, a weight estimation model for inter-satellite links is established, and the weight formula is as follows:

[0167]

[0168] in, Indicates at time From satellite node To satellite node The overall weight of the links; Indicates the weighting coefficient of the bandwidth factor; Indicates the weighting coefficient of storage factors; This represents the weighting coefficient of the distance factor; This represents the actual physical distance of the inter-satellite link;

[0169]

[0170] in, This represents the normalized ratio of the current link bandwidth to the maximum bandwidth. This represents the available bandwidth of the current link; This is represented as the maximum theoretical bandwidth of the link; a threshold mechanism is introduced into the storage weight, and the weight drops sharply when the storage rate is greater than 80%, which can greatly avoid storage overflow;

[0171]

[0172] in, Indicates satellite node Metrics related to remaining storage capacity; Indicates satellite node The current used storage capacity; Indicates satellite node Total storage capacity;

[0173] If there is no suitable secondary node under the current priority level, then query the secondary nodes of the next lower priority level until a suitable secondary node is found or all possible nodes are completely traversed.

[0174] Step 6: Iterate through the results of the secondary node selection until a usable route is found or a result indicating that a link cannot be established is returned; including:

[0175] Any node that has been included in the current node will be added to a memory node list. This list ensures that no closed loop will occur during the iteration process. Any node added to this list will not be considered as an optional secondary node in subsequent iterations.

[0176] When the current node queries a secondary node, there are two possibilities: a suitable secondary node is found, or no suitable secondary node is found after traversal. If the current node finds a suitable secondary node, it is added to the routing sequence and the memory node list, and the found secondary node is set as the current node. If no suitable secondary node is found after traversal, the current node is considered a closed node, its predecessor in the routing sequence is set as the current node, and the selection of a secondary node is repeated. This process is repeated until a usable route is found or a result indicating that a link cannot be established is returned.

[0177] Specifically, by repeating steps 3-5 above, where the source node is numbered "1" and the destination node is numbered "316", the link is determined as follows:

[0178]

[0179] Table 2. Initial Link Data Table

[0180] After node {18, 1} (307) is damaged, the communication link is rebuilt according to steps 3-5:

[0181]

[0182] Table 3. Reconstruction Link Data Table

[0183] It is evident that after the relay node was damaged, the link was quickly rebuilt, and the changes to the link were kept to a minimum.

[0184] The beneficial effects achieved by the above are as follows: By establishing a low-Earth orbit (LEO) communication constellation based on the Walker-Delta configuration, topological analysis of the LEO constellation orbit is conducted to establish a multi-level hierarchy based on point distance. This is combined with the communication weights between nodes, i.e., the values ​​of each edge in the topology, to spontaneously recursively reconstruct damaged links. This enables the replanning and reconstruction of communication routes in the event of large-scale random node damage and a lack of global network information. It possesses advantages such as rapid response, decentralization, and spontaneous network reorganization, providing technical support and reference for the spontaneous reconstruction of links after random node damage in large-scale LEO constellations, and solving related engineering problems.

[0185] Working principle: By designing the network topology, adopting the basic idea of ​​distributed networking, and using the iterative algorithm, the network can quickly rebuild links in the face of large-scale random network damage. While ensuring autonomous and rapid link building, the optimal routing path is found.

[0186] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0187] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for large-scale random node loss rerouting in low-Earth orbit satellite constellations, characterized in that, Includes the following steps: Step 1: Establish a low-Earth orbit communication satellite constellation topology model; Step 2: Identify the communication link nodes that need to be established and construct the data packet structure for inter-node interaction; Step 3: Calculate the possible hop count list based on the routing rules, and simplify the topology model, compressing the three-dimensional topology into a planar local topology; Step 4: Based on the initial node, prioritize the secondary nodes; Step 5: Calculate edge weights within nodes of the same priority level sequentially, and determine the next-hop node, including: Based on the maximum of three levels, the weights of each hop edge within the same level are calculated sequentially. A weight estimation model for inter-satellite links is established, and the weight formula is as follows: （1）； in, Indicates at time From satellite node To satellite node The overall weight of the links; Indicates the weighting coefficient of the bandwidth factor; Indicates the weighting coefficient of storage factors; This represents the weighting coefficient of the distance factor; This represents the actual physical distance of the inter-satellite link; （2）； in, This represents the normalized ratio of the current link bandwidth to the maximum bandwidth. This indicates the currently available bandwidth of the current link; This represents the maximum theoretical bandwidth of the current link; （3）； in, Indicates satellite node Metrics related to remaining storage capacity; Indicates satellite node The current used storage capacity; Indicates satellite node Total storage capacity; If there is no suitable secondary node under the current priority level, then query the secondary nodes of the next priority level until a suitable secondary node is found or all possible nodes are completely traversed. Step 6: Iterate through the results of the secondary node selection until a usable route is found or a result indicating that a link cannot be established is returned.

2. The method for large-scale random node loss routing replanning for low-Earth orbit satellite constellations according to claim 1, characterized in that, Step 1 involves establishing a low-Earth orbit communication satellite constellation topology model, including: Let the satellite's orbital altitude be Inclination angle is And all tracks are circular tracks; Consider two satellites, A and B, located between two adjacent orbits. Let the phase difference between A and B be denoted as . ; Since the two satellites have the same orbital period, the phase difference between their nodes remains constant. Therefore, at time t, the angle between the two satellites and the line connecting them to the Earth's center is... Represented as: （4）； in, The phase difference between satellites A and B; The difference in longitude between the ascending nodes of the two satellites; and These are the phases of satellite nodes A and B at time t, respectively; The phase of node B is then expressed as: （5）； The link distance between satellites A and B is: （6）； Among them, R E It is expressed as the average radius of the Earth.

3. The method for large-scale random node loss routing replanning for low-Earth orbit satellite constellations according to claim 2, characterized in that, After determining the link distance between satellites A and B, the following is included: Link elevation angle from satellite A to satellite B and azimuth for: （7）； （8）； in: （9）； （10）； （11）； At the same time, it was concluded that The scope is: （12）； （13）。 4. The method for large-scale random node loss routing replanning for low-Earth orbit satellite constellations according to claim 3, characterized in that, After determining the link distance between satellites A and B, the following is also included: If let Then the expressions for the link distance and pointing angle between the two satellites simplify to: （14）； To clarify the variation of inter-satellite links with phase, further analysis of the links is conducted: （15）； right Differentiate, the expression is: （16）； Based on the previous analysis: （17）； Therefore, the equation for the inter-satellite link variation with phase can be derived as follows: （18）； Obviously, by setting the above equation to 0, we can obtain the extreme case of the inter-satellite link, where: （19）； in, It is represented as a set of integers.

5. The method for large-scale random node loss route replanning for low-Earth orbit satellite constellations according to claim 4, characterized in that, Further analysis of the link includes: Combining equations 4 and 19, we arrive at the following conclusion: when When k is even: （20）； （21）； when When k is odd: （22）； （23）。 6. The method for large-scale random node loss routing replanning for low-Earth orbit satellite constellations according to claim 1, characterized in that, Step 2, based on the construction of the inter-node interaction data packet structure, includes: The TCP / IP protocol is used to complete communication between nodes; Based on the inter-satellite network and topology model, a data packet encapsulation structure is constructed; the data packet encapsulation structure includes: packet identifier, source node satellite identifier, destination node satellite identifier, source node IP, destination node IP, packet length or multiple packet continuation identifier, packet data, and checksum.

7. The method for large-scale random node loss route replanning for low-Earth orbit satellite constellations according to claim 1, characterized in that, In step 3, a list of possible hop counts is calculated based on routing patterns, and the topology model is simplified, compressing the three-dimensional topology into a planar local topology, including: In the network topology, select any two nodes A and B. Calculate the hop count limit between A and B using Equations 4-23 based on their node numbers. The expression is as follows: （24）； in, and These represent the node numbers of A and B in the network, respectively.

8. The method for large-scale random node loss route replanning for low-Earth orbit satellite constellations according to claim 7, characterized in that, After calculating the limit of the number of jumps between points A and B, the following is included: Based on the node numbers of nodes A and B, the total number of orbits, and the number of nodes on the orbital plane, the reverse links of nodes A and B are calculated, and expressed as follows: （25）； （26）； （27）； in, This represents the total number of orbital surfaces; This represents the total number of satellite nodes on each orbital plane; This is represented by taking an outer arc in both directions, indicating a path around the outer edge of the torus in the two-dimensional topology; This is represented as moving in an outer arc in the direction of the orbital plane number and in an inner arc in the direction of the phase within the orbit; This is represented as moving in an inner arc in the direction of the orbital plane number and in an outer arc in the direction of the phase within the orbit; By comparison Based on the above three results, the shortest hop count between nodes A and B in the local area is obtained, the logical boundaries that the shortest link may cross in the three-dimensional topology are determined, and the planar local topology is derived, simplifying the entire three-dimensional topology into a local planar topology centered on A and B.

9. The method for large-scale random node loss routing replanning for low-Earth orbit satellite constellations according to claim 1, characterized in that, In step 6, the selection results of secondary nodes are used for iterative looping until a usable route path is found or a result indicating that a link cannot be established is returned, including: When the current node queries a sub-node, there are two possibilities: a suitable sub-node is found, or no suitable sub-node is found after the traversal is completed. If the current node finds a suitable secondary node, then the current node is added to the routing sequence and the list of memory nodes, and the found secondary node is set as the current node. If no suitable secondary node is found after the current node is traversed, the current node is considered a closed node, the previous node of the current node in the routing sequence is set as the current node, and the selection of secondary nodes is performed again. The process is repeated iteratively until a usable route is found or a result indicating that a link cannot be established is returned.

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