A method and system for scheduling optimization of multi-link data transmission of an earth observation satellite

Abstract

The application provides a scheduling optimization method and system for multi-link data transmission of an earth observation satellite. In a network topology structure, a path indicator of a sub-flow, a data rate of the sub-flow, and a data transmission time of a source node are obtained according to a network topology graph of each time slot in a task cycle, capacities of various links, sources of requested data, a data amount required to be transmitted by each source node, and a destination node set. The obtained information is subjected to bandwidth constraint and data amount constraint, and a shortest path set from the source node to the destination node is obtained with a total data transmission time being minimized as an optimization target. Then, the shortest path set from a source satellite to each target ground station is calculated, and an optimal path is selected based on a joint degree and a survival time. Based on the selected optimal path, bandwidth resources are allocated according to a priority of a source satellite task, and data transmission from the source satellite to a destination is performed to realize multi-link efficient data transmission of data and improve data transmission efficiency.

Description

Technical Field

[0001] The present invention relates to the field of routing technology, and more particularly to a scheduling optimization method and system for multi-link data transmission in an earth observation satellite system. Background Art

[0002] Routing technology is used in computer networks to determine the path that data packets take from source to destination. It is a core technology that ensures the effective and efficient transmission of data packets within the network. It uses various algorithms and protocols to select the optimal path. With the development of network technology, routing technology is also constantly evolving and innovating to cope with increasingly complex network environments and demands.

[0003] The development of Earth observation technology began with aerospace observation. Relying on optoelectronic instruments carried by space platforms such as satellites, spacecraft, and space shuttles, Earth observation uses a variety of detection methods to monitor the Earth's environment and human activities. Entering the 21st century, with the rapid development of advanced technologies such as remote sensing, computing, data communications, and sensors, Earth observation technology has ushered in new opportunities for development, forming a comprehensive observation system covering all aspects of the land, ocean, and atmosphere. Earth observation satellites are equipped with multiple high-resolution sensors that capture Earth observation data from space for various missions. Emerging Earth observation constellations also generate massive amounts of data daily. In emergency situations such as disaster response, optoelectronic data acquired in space must be downloaded to ground-based mission centers as quickly as possible. Therefore, optimizing the data transmission process for Earth observation constellations is crucial for the Earth observation industry.

[0004] Numerous previous works have investigated methods for transmitting data from Earth observation satellites. At a high level, existing methods can be categorized into three main types: (a) downloading via a network of ground stations; (b) downloading via geostationary Earth (GEO) relays; and (c) downloading via LEO satellite routes. However, these existing methods suffer from numerous issues with efficiency, latency, and scalability. Due to the high dynamism of observation satellites and the Earth's rotation, network topology frequently changes, and the short duration of the link between the ground station and the source satellite, the transmission of large amounts of observation data over extended periods of time is impractical. Summary of the Invention

[0005] In order to solve the problem that the network topology changes frequently, the link duration between the ground station and the source satellite is short, and a large amount of observation data cannot be transmitted for a long time, the present invention proposes a scheduling optimization method and system for multi-link data transmission of Earth observation satellites to improve the efficiency of data transmission.

[0006] In order to achieve the above technical effects, the technical solutions of the present invention are as follows:

[0007] A scheduling optimization method for multi-link data transmission of an earth observation satellite comprises the following steps:

[0008] Connecting multiple ground workstation nodes, observation satellite nodes, relay satellite nodes and Earth observation satellite mission center nodes to form a network topology structure;

[0009] According to the network topology diagram of each time slot in the task cycle, the capacity of each link, the source of the requested data, the amount of data that each source node needs to transmit, and the set of destination nodes, the path indicator of the subflow, the subflow data rate, and the data transmission time of the source node are obtained;

[0010] The path indicator, the data rate of the subflow, and the data transmission time of the source node are subjected to bandwidth constraints and data volume constraints, with minimizing the total data transmission time as the optimization goal, to obtain a set of shortest paths from the source node to the destination node;

[0011] The Dijkstra algorithm is used to calculate the shortest path set from the source satellite to each target ground station, and the optimal path is selected based on the joint degree and survival time;

[0012] Based on the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite mission, and the bandwidth of each source satellite is evenly distributed to the selected transmission path to perform data transmission from the source satellite to the destination.

[0013] The present invention also provides a scheduling optimization system for multi-link data transmission of an earth observation satellite, comprising:

[0014] A network structure module is used to interconnect multiple ground workstation nodes, observation satellite nodes, transfer satellite nodes and Earth observation satellite mission center nodes to form a network topology structure;

[0015] a data acquisition module, configured to obtain a subflow path indicator, a subflow data rate, and a data transmission time of a source node based on a network topology diagram of each time slot in a task cycle, the capacity of each link, the source of the requested data, the amount of data to be transmitted by each source node, and a set of destination nodes;

[0016] A shortest path selection module is configured to obtain a set of shortest paths from a source node to a destination node by applying bandwidth constraints and data volume constraints to the path indicator, the data rate of the subflow, and the data transmission time of the source node, with the optimization goal of minimizing the total data transmission time;

[0017] The optimal path selection module is used to calculate the shortest path set from the source satellite to each target ground station using the Dijkstra algorithm and select the optimal path based on the joint degree and survival time;

[0018] The bandwidth allocation module is used to allocate bandwidth resources based on the selected optimal path and the priority of the source satellite mission, evenly distribute the bandwidth of each source satellite to the selected transmission path, and perform data transmission from the source satellite to the destination.

[0019] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0020] The present invention proposes a scheduling optimization method and system for multi-link data transmission of an Earth observation satellite. The method combines path indicators, substream data rates, and data transmission time of a source node with bandwidth constraints and data volume constraints, with minimizing the total data transmission time as the optimization goal. A set of shortest paths from the source node to the destination node is obtained, and bandwidth utilization is maximized by minimizing the total data transmission time, thereby ensuring optimal resource utilization and reducing waiting time. Secondly, a Dijkstra algorithm is used to calculate a set of shortest paths from the source satellite to each target ground station, and an optimal path is selected based on the joint degree and survival time to improve data transmission efficiency. Finally, based on the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite mission, and the bandwidth of each source satellite is evenly distributed to the selected transmission path. Data transmission from the source satellite to the destination is performed to ensure data transmission efficiency, thereby achieving efficient and reliable completion of large-scale Earth observation data download tasks in a dynamically changing network environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The flowchart of the scheduling optimization method for multi-link data transmission of an earth observation satellite is shown in an embodiment of the present invention.

[0022] Figure 2 This is a general structural diagram of a method for scheduling optimization of multi-link data transmission for an Earth observation satellite according to an embodiment of the present invention.

[0023] Figure 3 FIG. 4 is a shortest path set diagram for a time slot according to an embodiment of the present invention.

[0024] Figure 4 This is a pseudo code diagram of an algorithm for calculating the shortest path shown in an embodiment of the present invention.

[0025] Figure 5 This is a pseudo code diagram of an algorithm for calculating bandwidth allocation according to an embodiment of the present invention.

[0026] Figure 6 This is an architecture diagram of a scheduling optimization system for multi-link data transmission of an Earth observation satellite according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0028] The terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The singular forms "a," "the," and "the" used in this invention and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0029] It should be understood that although the terms "first," "second," "third," etc. may be used in the present invention to describe various information, such information should not be limited to these terms. These terms are merely used to distinguish information of the same type from one another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present invention. Depending on the context, the term "if" as used herein may be interpreted as "when," "when," or "in response to determining."

[0030] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] This embodiment proposes a scheduling optimization method for multi-link data transmission of earth observation satellites, such as Figure 1 FIG. 1 is a flowchart of the method for optimizing scheduling of multi-link data transmission for an earth observation satellite according to the present embodiment.

[0033] The present embodiment provides a method for optimizing scheduling of multi-link data transmission for an Earth observation satellite, including the following steps:

[0034] Connecting multiple ground workstation nodes, observation satellite nodes, relay satellite nodes and Earth observation satellite mission center nodes to form a network topology structure;

[0035] According to the network topology diagram of each time slot in the task cycle, the capacity of each link, the source of the requested data, the amount of data that each source node needs to transmit, and the set of destination nodes, the path indicator of the subflow, the subflow data rate, and the data transmission time of the source node are obtained;

[0036] The path indicator, the data rate of the subflow, and the data transmission time of the source node are subjected to bandwidth constraints and data volume constraints, with minimizing the total data transmission time as the optimization goal, to obtain a set of shortest paths from the source node to the destination node;

[0037] The Dijkstra algorithm is used to calculate the shortest path set from the source satellite to each target ground station, and the optimal path is selected based on the joint degree and survival time;

[0038] Based on the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite mission, and the bandwidth of each source satellite is evenly distributed to the selected transmission path to perform data transmission from the source satellite to the destination.

[0039] This embodiment first interconnects multiple ground workstation nodes, observation satellite nodes, transit satellite nodes, and an Earth observation satellite mission center node to form a network topology. Second, based on the network topology diagram for each time slot within a mission cycle, the capacity of each link, the source of the requested data, the amount of data required to be transmitted by each source node, and the set of destination nodes, a subflow path indicator, subflow data rate, and source node data transmission time are obtained. Next, the path indicator, subflow data rate, and source node data transmission time are subjected to bandwidth constraints and data volume constraints. With the optimization goal of minimizing total data transmission time, a set of shortest paths from the source node to the destination node is obtained. By minimizing total data transmission time, bandwidth utilization is maximized, thereby improving transmission reliability. Then, the Dijkstra algorithm is used to calculate the set of shortest paths from the source satellite to each target ground station, and the optimal path is selected based on the joint degree and survival time to improve data transmission efficiency. Finally, based on the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite mission, and the bandwidth of each source satellite is evenly distributed to the selected transmission path. Data transmission from the source satellite to the destination is performed to ensure data transmission efficiency and fairness.

[0040] In an optional embodiment, due to the high-speed movement of satellites and the rotation of the earth, the network topology changes over time, so it is necessary to recalculate the network topology in each time slot t. The connection between low-earth orbit satellites and ground stations usually changes within a few minutes, but the entire satellite topology is considered constant in a short time. Assuming that time is segmented, the network topology in time slot t∈T{1,2…,Γ} is represented by Figure G t (V, E(t)) is represented by , where T is the mission period. Here, the duration of each time slot is set to 1 second. The vertex set V includes the Earth observation satellite mission center (i.e., the ground destination), available ground stations, and all satellites (i.e., the observation satellites that obtain raw data in space, and the forwarding satellites that forward the observation data from the source node to the ground destination). The overall structure diagram is shown as follows: Figure 2shown.

[0041] In an optional embodiment, it is assumed that there are n earth observation satellites S = {s1, s2, ..., s n}, indexed by i, which have data to transmit for a certain observation data request. The edge set E(t) describes the connectivity between vertices in time slot t, where an edge e(a,b)∈E(t),a,b∈V indicates that there is an available link between nodes a and b in time slot t.

[0042] The link capacity matrix is ​​represented as The source with the requested data The total amount of data that each source node needs to transmit is D = {d1, d2, ..., d n}, destination node dst∈V, assuming that each source satellite has Ψ interfaces, then the source satellite can establish at most Ψ sub-flows with the destination at the same time. The sub-flow indexed by j of the i-th source satellite in time slot t is denoted as f ij (t), r ij (t) is the sub-flow f ij (t) corresponds to the data rate, for f ij (t) The path passed, define a binary variable As a path indicator, when the path indicator is 1, the subflow indexed by j of the i-th source satellite in time slot t passes through the link edge between nodes a and b; otherwise, the path indicator is 0; its expression is:

[0043]

[0044] in, Indicates the path indicator, f ij (t) represents the subflow indexed by j of the i-th source satellite in time slot t, a represents node a, b represents node b, and (a, b) represents the link between nodes a and b.

[0045] The path indicator of each sub-flow in each time slot is represented as The sub-flow data rate allocation for each flow is represented as

[0046] According to the network topology G of each time slot in the task cycle T t (V,E(t)), link capacity matrix The source with the requested data The total amount of data that each source satellite needs to transmit is D = {d1, d2, ..., d n}, destination node dst∈V, thereby first obtaining the path indicator f ij (t) represents the substream indexed by j of the i-th source satellite in time slot t, if f ij(t) passes through the edge (a,b), then Otherwise, it is 0; then, the sub-flow f of each flow is obtained. ij (t) Data rate allocation The final source s i Completion time where t′ refers to the source s i The number of time slots that elapse from the start of data transmission until it successfully transmits the data assigned to it, so t′ is actually a measure of the source s i An indicator of the time required to complete a transmission task, reflecting the delay and efficiency of the transmission process. Where Z represents a set of integers, which is used to limit the source index i to an integer, thus ensuring that each source has a unique, discrete identifier.

[0047] In an optional embodiment, the bandwidth constraint includes that the bandwidth usage of any communication link is less than or equal to the maximum data transmission rate in time slot t; its expression is:

[0048]

[0049] in, It represents the capacity of the edge (i.e. link) (a, b) in time slot t. Specifically, a and b are nodes, which can be satellites or ground stations, and the edge (a, b) represents the communication link between them. It is the maximum data transmission rate of the link in time slot t, which defines the maximum amount of data that can be transmitted from node a to node b in a specific time t, usually in bits per second (bps).

[0050] The data volume constraint includes that the amount of data flowing into and out of any intermediate node in the network topology is equal, unless the node is a source node or a destination node; its expression is:

[0051]

[0052] Among them, ∏(a,i,j,t) represents the node indicator, when a=s i That is, when node a is the source node s i When , the value of ∏(a,i,j,t) is 1; it means that for the source node s i, only one link from that node is used to send data. When a = dst, that is, when node a is the destination node dst, the value of ∏(a, i, j, t) is -1; this means that for the destination node, only one link entering that node is used to receive data. For any intermediate node a that is not a source node or a destination node, the value of ∏(a, i, j, t) is 0. This means that for all intermediate nodes, the amount of data flowing in and out must be equal to ensure flow conservation. The source node data volume constraint limits the subflow data rate to a non-negative value.

[0053] In this embodiment, the path indicator, the data rate of the sub-flow, and the data transmission time of the source node are constrained by bandwidth and data volume, with the optimization goal of minimizing the total data transmission time, thereby maximizing bandwidth utilization and improving transmission reliability, and obtaining the shortest path set from the source node to the destination node. Specifically, the shortest path set for a time slot in data multi-link data transmission is as follows: Figure 3 shown.

[0054] In an optional embodiment, the set of shortest paths from the source satellite to each target ground station calculated using the Dijkstra algorithm is within a static duration, where the static duration is formed by combining multiple consecutive time slots; the static duration represents, in time slot t0, the shortest duration of all component links of the path minus the initial time; its expression is:

[0055]

[0056] Where, PSD t0 represents the static duration of the path at time slot t0, t represents the time slot, t0 represents the initial time, P t0 represents the path currently used by each source node, and E(t) represents the edge set.

[0057] The path static duration may be updated at the beginning of each path static duration or after performing path selection and bandwidth allocation when some source nodes complete the transmission process.

[0058] In this embodiment, time slots are merged. When there is not much data to transmit, the transmission process is likely to complete before the network topology changes. Even if the topology changes, the transmission process remains stable as long as no transmission paths are affected. This reduces the problem to several simple subproblems where the path sets remain static for different durations. The data rate and loss rate remain constant for the duration of these static paths, as no paths are affected.

[0059] In an optional embodiment, at the beginning of each time slot, the Dijkstra algorithm is used to calculate all the shortest paths from each source satellite node to the destination ground station under the current topology conditions. The pseudo code of the algorithm is as follows: Figure 4 The specific steps are as follows:

[0060] First, initialize and create the distance dictionary distances, which is used to record the distance between the node and the source node s i Initialize the distance of all nodes to infinity, except for the source node s i , and its distance is initialized to 0. Create a predecessor dictionary predecessors to record the predecessor nodes of each node. Initially it is an empty list. Use queue queue to store the nodes to be processed. Initially, the source node s i and its distance 0 is added to the queue. After that, each source node s i Traverse all ground stations gs as intermediate nodes and use Dijkstra algorithm to output the source node s under the current topology G(V,E(t)) i All shortest paths to the ground station gs, each path is added to the edge from the ground station to the target node dst. Output returns the set of candidate paths for all source nodes Then calculate the joint degree and survival time of each path. Combine the joint degree and survival time to calculate the priority, and take the path with the highest priority as the optimal path.

[0061] The path jointness measures the number of links shared by multiple paths in the network. A higher path jointness means more overlap between these paths on some links, which may lead to bandwidth contention or congestion. In a network, avoiding excessive sharing of links between paths can reduce this contention and improve the network's data transmission efficiency. Suppose there are multiple paths P1, P2, ..., P n , each path has a certain set of links, and the path union degree U p It can be defined as the overlap of all links in path p:

[0062]

[0063] Among them, U p represents the path jointness, e represents the link, p represents the path, jointness(e) represents the number of times link e appears in other paths, and paths with lower jointness indicate that these paths have fewer shared links between different paths;

[0064] The survival time refers to the time a path remains available before the network topology changes. Due to the high dynamics of satellite communications, the communication link between the satellite and the ground station will change in different time periods. The survival time is calculated to determine the maximum length of time a path can remain stable and available. Assume that the path p = (s i ,g1,g2,…,g k ,d) consists of multiple intermediate nodes, where g1,g2,…,g k is a transit satellite node, s i is the source satellite, d is the target ground station. Path survival time T p Determined by the shortest available time of each link in the path:

[0065]

[0066] Among them, T P represents the path survival time, Indicates the path survival time of the first transit satellite node, Indicates the path survival time of the second transit satellite node, represents the path survival time of the k-th transit satellite node, is a link (g i-1 ,g i ) or (g i ,g i+1 ) depends on the relative positions and orbits of the satellites.

[0067] The priority obtained by combining the joint degree and the survival time includes calculating the ratio of the path joint degree and the path survival time; the expression is:

[0068]

[0069] Among them, M p represents the priority index, T P represents the path survival time, U p Indicates the path jointness. Paths with longer survival times and lower jointness have higher priority. Therefore, when selecting a path, paths with longer survival times and lower jointness are preferred.

[0070] In this embodiment, the Dijkstra algorithm is used to calculate the set of shortest paths from the source satellite to each target ground station. The union degree of each path, i.e., the degree of overlap between the paths, and the survival time, i.e., the time during which the path can remain stable, are calculated. The path with the highest priority is used as the optimal path, thereby improving data transmission efficiency.

[0071] In an optional embodiment, bandwidth resources are allocated based on the priority of the source satellite missions. Each source satellite will receive a total bandwidth, and then each source satellite will have multiple paths for data transmission. The bandwidth of each source satellite is evenly distributed to the selected transmission paths, so that time-sensitive tasks can be processed more quickly. The pseudo code of the algorithm is as follows: Figure 5 First, each source satellite will process a specific task, and the task priority expression is:

[0072] W={w1,w2,…w n}

[0073] Among them, W represents the mission priority, w1 represents the mission priority of the first source satellite, w2 represents the mission priority of the second source satellite, and w n Indicates the priority of the nth source satellite mission.

[0074] Calculate the bandwidth allocated to each source satellite; the expression is:

[0075]

[0076] Where, represents the bandwidth of each source satellite, w i Indicates the priority of the source satellite mission, H total Indicates the total bandwidth;

[0077] Calculate the bandwidth allocation on each data transmission path of the source satellite; the expression is:

[0078]

[0079] Where b p Indicates the bandwidth of each data transmission path, Indicates the path number of the source satellite.

[0080] In this embodiment, based on the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite mission, the bandwidth of each source satellite is evenly distributed to the selected transmission path, and data transmission from the source satellite to the destination is performed to achieve multi-link and efficient data transmission.

[0081] In an optional embodiment, changes in the network topology are detected in real time during data transmission. If changes in the network topology are detected, the optimal path is recalculated and bandwidth is reallocated to adjust the data transmission path.

[0082] If any anomalies are encountered during transmission, including link disconnection, data loss, node failure (possibly a hardware failure in a satellite or ground station, causing it to malfunction), signal interference (external factors such as solar storms and electromagnetic interference degrade the communication link quality), traffic congestion (multiple satellites simultaneously attempting to transmit large amounts of data over the same link in certain hotspots or time periods, causing network congestion), time synchronization issues (due to the high-speed movement of satellites, the time between nodes may be out of sync, causing packet reordering), and software errors (possible software issues on satellites or ground stations, affecting normal data processing and forwarding), the system will automatically take appropriate recovery measures, including rescheduling data flows, switching to alternative paths, and retransmission mechanisms. For lost packets, an automatic retransmission request mechanism is activated to ensure that the receiving end receives all data. If packet loss is caused by a brief link outage, partial retransmission can be performed after the link is restored, rather than a full retransmission. Intelligent routing adjustments monitor network status in real time and, upon detecting anomalies, initiate new routing calculations to replan the optimal path. Faulty nodes or links are quickly removed from the routing table and alternative paths are sought.

[0083] Example 2

[0084] This embodiment proposes a scheduling optimization system for multi-link data transmission of an earth observation satellite, and applies the scheduling optimization method for multi-link data transmission of an earth observation satellite proposed in Example 1. Figure 6 , which is an architecture diagram of the scheduling optimization system for multi-link data transmission of earth observation satellites according to this embodiment.

[0085] This embodiment proposes a scheduling optimization system for multi-link data transmission of an Earth observation satellite, including:

[0086] A network structure module is used to interconnect multiple ground workstation nodes, observation satellite nodes, transfer satellite nodes and Earth observation satellite mission center nodes to form a network topology structure;

[0087] a data acquisition module, configured to obtain a subflow path indicator, a subflow data rate, and a data transmission time of a source node based on a network topology diagram of each time slot in a task cycle, the capacity of each link, the source of the requested data, the amount of data to be transmitted by each source node, and a set of destination nodes;

[0088] A shortest path selection module is configured to obtain a set of shortest paths from a source node to a destination node by applying bandwidth constraints and data volume constraints to the path indicator, the data rate of the subflow, and the data transmission time of the source node, with the optimization goal of minimizing the total data transmission time;

[0089] The optimal path selection module is used to calculate the shortest path set from the source satellite to each target ground station using the Dijkstra algorithm and select the optimal path based on the joint degree and survival time;

[0090] The bandwidth allocation module is used to allocate bandwidth resources based on the selected optimal path and the priority of the source satellite mission, evenly distribute the bandwidth of each source satellite to the selected transmission path, and perform data transmission from the source satellite to the destination.

[0091] It can be understood that the system of this embodiment corresponds to the method of the above-mentioned embodiment 1, and the options in the above-mentioned embodiment 1 are also applicable to this embodiment, so they will not be described again here.

[0092] Example 3

[0093] This embodiment proposes a computer device including a memory and a processor, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the processor executes all or part of the steps of a scheduling optimization method for multi-link data transmission of an earth observation satellite as proposed in Example 1.

Claims

1. A scheduling optimization method for multi-link data transmission of an Earth observation satellite, characterized in that: The following steps are involved: Connecting multiple ground workstation nodes, observation satellite nodes, relay satellite nodes and Earth observation satellite mission center nodes to form a network topology structure; According to the network topology diagram of each time slot in the task cycle, the capacity of each link, the source of the requested data, the amount of data that each source node needs to transmit, and the set of destination nodes, the path indicator of the subflow, the subflow data rate, and the data transmission time of the source node are obtained; The path indicator, sub-flow data rate, and data transmission time of the source node are subjected to bandwidth constraints and data volume constraints, with minimizing the total data transmission time as the optimization goal, to obtain a set of shortest paths from the source node to the destination node; The Dijkstra algorithm is used to calculate the shortest path set from the source satellite to each target ground station, and the optimal path is selected based on the joint degree and survival time; The joint degree is defined as the overlap of all links in the path, and its expression is: Where U p represents the path jointness, e represents the link, p represents the path, and jointness(e) represents the number of times link e appears in other paths; The path survival time is determined by the shortest available time of each link in the path, and its expression is: Where, T P represents the path survival time, Indicates the path survival time of the first transit satellite node, Indicates the path survival time of the second transit satellite node, represents the path survival time of the k-th transit satellite node; The priority is calculated by combining the joint degree and the survival time, including the ratio of the calculated path joint degree and the path survival time; Its expression is: Where M p represents the priority index, T P represents the path survival time, U p represents the path joint degree; Based on the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite mission, and the bandwidth of each source satellite is evenly distributed to the selected transmission path to perform data transmission from the source satellite to the destination; The method of allocating bandwidth resources according to the priority of the source satellite missions and evenly distributing the bandwidth of each source satellite to the selected transmission path includes the following steps: Calculate the bandwidth allocated to each source satellite; the expression is: Where, represents the bandwidth of each source satellite, w i Indicates the priority of the source satellite mission, H total Indicates the total bandwidth; Based on the ratio of each source satellite's bandwidth to the number of source satellite paths, the bandwidth allocation on each data transmission path of the source satellite is calculated, and the bandwidth of each source satellite is evenly distributed to the selected transmission path; the expression is: Where b p Indicates the bandwidth of each data transmission path, Indicates the path number of the source satellite.

2. The method for scheduling and optimizing multi-link data transmission of an Earth observation satellite according to claim 1, wherein: The bandwidth constraint includes that the bandwidth usage of any communication link is less than or equal to the maximum data transmission rate within time slot t; the data volume constraint includes that the amount of data flowing into and out of any intermediate node in the network topology is equal; the source node data volume constraint includes that the sub-flow data rate is a non-negative value.

3. The method for scheduling and optimizing multi-link data transmission of an Earth observation satellite according to claim 1, wherein: When the Dijkstra algorithm is used to calculate the shortest path set from the source satellite to each target ground station, the following steps are also included: Combine multiple consecutive time slots into a static duration of a path, and use the Dijkstra algorithm to calculate the set of shortest paths from the source satellite to each target ground station within the static duration. The static duration in time slot t0 represents the shortest duration of all component links of the path minus the initial time. Its expression is: Where, PSD t0 represents the static duration of the path at time slot t0, t represents the time slot, t0 represents the initial time, P t0 represents the path currently used by each source node, and E(t) represents the edge set.

4. The method for scheduling and optimizing multi-link data transmission for an Earth observation satellite according to claim 1, wherein: The specific steps of using the Dijkstra algorithm to calculate the shortest path set from the source satellite to each target ground station are: First, initialize the distance dictionary and initialize the distance of all nodes to infinity; Create a predecessor dictionary, which is initially an empty list. Use a queue to store the nodes to be processed. Initially add the source node and its distance to the queue. Each source node traverses all ground stations as intermediate nodes and uses the Dijkstra algorithm to output all the shortest paths from the source node to the ground station under the current topology network graph. Each path adds an edge from the ground station to the target node. Output the candidate path set returning all source nodes and calculate the joint degree and survival time of each path; The priority is calculated by combining the joint degree and survival time, and the path with the highest priority is taken as the optimal path.

5. The method for scheduling and optimizing multi-link data transmission of an Earth observation satellite according to claim 1, wherein: The performing of data transmission from the source satellite to the destination further comprises the following steps: During data transmission, changes in the network topology are detected in real time. If changes are detected in the network topology, the optimal path is recalculated and bandwidth is reallocated to adjust the data transmission path.

6. A scheduling optimization system for multi-link data transmission of an Earth observation satellite, applying the scheduling optimization method for multi-link data transmission of an Earth observation satellite according to any one of claims 1 to 5, characterized in that: include: A network structure module is used to interconnect multiple ground workstation nodes, observation satellite nodes, transfer satellite nodes and Earth observation satellite mission center nodes to form a network topology structure; a data acquisition module, configured to obtain a subflow path indicator, a subflow data rate, and a data transmission time of a source node based on a network topology diagram of each time slot in a task cycle, the capacity of each link, the source of the requested data, the amount of data to be transmitted by each source node, and a set of destination nodes; A shortest path selection module is configured to obtain a set of shortest paths from a source node to a destination node by applying bandwidth constraints and data volume constraints to the path indicator, the data rate of the subflow, and the data transmission time of the source node, with the optimization goal of minimizing the total data transmission time; The optimal path selection module is used to calculate the shortest path set from the source satellite to each target ground station using the Dijkstra algorithm and select the optimal path based on the joint degree and survival time; The bandwidth allocation module is used to allocate bandwidth resources based on the selected optimal path and the priority of the source satellite mission, evenly distribute the bandwidth of each source satellite to the selected transmission path, and perform data transmission from the source satellite to the destination.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for optimizing scheduling of multi-link data transmission for an earth observation satellite according to any one of claims 1 to 5 is implemented.

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