Scheduling optimization method and system for multilink data transmission of earth observation satellite

Abstract

The invention provides a scheduling optimization method and system for multi-link data transmission of an earth observation satellite, and the method comprises the steps: carrying out the scheduling optimization of the multi-link data transmission in a network topology structure according to a network topological graph of each time slot in a task period, the capacity of each link, the source of request data, the data size needing to be transmitted by each source node, and a destination node set; obtaining the path indicator of the substream, the substream data rate and the data transmission time of the source node; carrying out bandwidth constraint and data volume constraint on the obtained information, and taking minimization of total transmission time of data as an optimization target to obtain a shortest path set from a source node to a destination node; then calculating a shortest path set from the source satellite to each target ground station, and selecting an optimal path based on the joint degree and the survival time; and on the basis of the selected optimal path, bandwidth resources are allocated according to the priority of the source satellite task, and data transmission from the source satellite to the destination is executed to realize multi-link high-efficiency data transmission of the data, so that the data transmission efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of routing selection, and more specifically 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 for data packets to be transmitted from the source node to the destination node. It is the core technology to ensure the effective and efficient transmission of data packets in the network. It uses different algorithms and protocols to select the best path. With the development of network technology, routing technology is also constantly evolving and innovating to cope with increasingly complex network environments and needs.

[0003] The development of earth observation technology started with aerospace earth observation, relying on optoelectronic instruments carried by space platforms such as satellites, spacecraft, and space shuttles, and using a variety of detection methods to conduct detection activities of the earth's environment and human activities. Entering the 21st century, with the rapid development of high-tech technologies such as remote sensing technology, computer technology, data communication, and sensor technology, earth observation technology has ushered in new development opportunities, forming a comprehensive observation system for all levels such as land, ocean, and atmosphere. Earth observation satellites are equipped with multiple high-resolution sensors that can capture earth observation data from space for various tasks. At the same time, emerging EO constellations generate a large amount of data every day. In emergency situations such as disaster response, optoelectronic data obtained in space needs to be downloaded to the ground mission center as soon as possible. Therefore, optimizing the data transmission process of earth observation constellations is crucial for the earth observation industry.

[0004] Many previous works have investigated methods for transmitting data from Earth observation satellites. At a high level, existing methods can be divided into three categories: (a) downloading via a network of ground stations; (b) downloading via geostationary (GEO) relays; and (c) downloading via LEO satellite routes. However, these existing methods have many problems in terms of efficiency, latency, and scalability. Due to the high dynamics of observation satellites and the rotation of the Earth, the network topology changes frequently, and the short duration of the link between the ground station and the source satellite, it is not possible to transmit large amounts of observation data for a long time. 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 solution of the present invention is 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 constrained by bandwidth constraints and data volume constraints, and the shortest path set from the source node to the destination node is obtained with the minimization of the total data transmission time as the optimization goal;

[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 is used to obtain a path indicator of a subflow, a subflow data rate, and a data transmission time of a source node according to 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] The shortest path selection module is used to obtain the shortest path set from the source node to the destination node by combining the path indicator, the data rate of the sub-flow, and the data transmission time of the source node with the bandwidth constraint and the data volume constraint, with the minimization of the total data transmission time as the optimization goal;

[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 technical solution of the present invention has the following beneficial effects:

[0020] The present invention proposes a scheduling optimization method and system for multi-link data transmission of an earth observation satellite. The method comprises the following steps: constraining a path indicator, a data rate of a substream, and a data transmission time of a source node through bandwidth constraints and data volume constraints, taking minimizing the total data transmission time as an optimization target, obtaining a set of shortest paths from a source node to a destination node, maximizing bandwidth utilization by minimizing the total data transmission time, thereby ensuring optimal use of resources and reducing waiting time; secondly, calculating a set of shortest paths from a source satellite to each target ground station by using a Dijkstra algorithm, and selecting an optimal path based on a joint degree and a survival time to improve data transmission efficiency; finally, based on the selected optimal path, allocating bandwidth resources according to the priority of a source satellite task, evenly allocating the bandwidth of each source satellite to a selected transmission path, executing data transmission from the source satellite to the destination to ensure data transmission efficiency, and realizing efficient and reliable completion of a large-scale earth observation data download task in a dynamically changing network environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flowchart of a method for optimizing scheduling of multi-link data transmission for an earth observation satellite according to an embodiment of the present invention.

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

[0023] Figure 3 The shortest path set diagram of a time slot is shown in an embodiment of the present invention.

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

[0025] Figure 5 The pseudo code diagram of the algorithm for calculating bandwidth allocation shown in an embodiment of the present invention.

[0026] Figure 6 The present invention is a diagram showing the architecture of a scheduling optimization system for multi-link data transmission on 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 shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0028] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more 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, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "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 an earth observation satellite, such as Figure 1 , which is a flow chart of the scheduling optimization method for multi-link data transmission of an earth observation satellite in this 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 constrained by bandwidth constraints and data volume constraints, and the shortest path set from the source node to the destination node is obtained with the minimization of the total data transmission time as the optimization goal;

[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] In this embodiment, a plurality of ground workstation nodes, observation satellite nodes, transit satellite nodes and earth observation satellite mission center nodes are interconnected to form a network topology structure; secondly, according to the network topology diagram of each time slot in the 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 destination node set, the path indicator of the substream, the substream data rate, and the data transmission time of the source node are obtained; next, the path indicator, the substream data rate, and the data transmission time of the source node are constrained by bandwidth constraints and data volume constraints, and the total transmission time of the data is minimized as the optimization goal to obtain the shortest path set from the source node to the destination node, and the bandwidth utilization is maximized by minimizing the total transmission time of the data, thereby improving the reliability of the transmission; then, 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 the survival time to improve the data transmission efficiency; finally, based on the selected optimal path, the bandwidth resources are allocated according to the priority of the source satellite mission, the bandwidth of each source satellite is evenly allocated to the selected transmission path, and the data transmission from the source satellite to the destination is performed to ensure the data transmission efficiency and fairness.

[0040] In an optional embodiment, due to the high-speed movement of the satellite and the rotation of the earth, the network topology changes with time, so it is necessary to recalculate the network topology in each time slot t. The connection between the low earth orbit satellite and the ground station 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 the time slot t∈T{1,2…,Γ} is represented by Figure G t (V, E(t)) represents, 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 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, they 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 simultaneously. The sub-flow indexed by j of the i-th source satellite in time slot t is denoted by 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 in time slot t of the i-th source satellite, 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-stream data rate allocation for each stream is characterized by

[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 i Completion time where t′ refers to the source s i The number of time slots 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 an integer set, which is used to limit the source index i to an integer, thereby 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 edge (i.e. link) (a,b) in time slot t. Specifically, a and b are nodes, which can be satellites or ground stations, and 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 target 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 this 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; it means that for the destination node, only one link entering the 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 traffic 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 constraints and data volume constraints, with the optimization goal of minimizing the total data transmission time, and thereby maximizing the bandwidth utilization, thereby improving the reliability of transmission, and obtaining the shortest path set from the source node to the destination node. Specifically, the shortest path set for a time slot in the data multi-link data transmission is as follows: Figure 3 shown.

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

[0055]

[0056] In the formula, 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, and when there is not much data to be transmitted, the transmission process is completely possible to end before the network topology changes. Even if the topology changes, the transmission process can remain stable as long as no transmission path is affected. Therefore, the problem can be simplified into multiple simple sub-problems where the path set can remain static for different durations. The data rate and loss rate remain the same during the static duration of these paths, and no path is affected.

[0059] In an optional embodiment, at the beginning of each time slot, the Dijkstra algorithm is used to calculate all shortest paths from each source satellite node to the destination ground station under the current topological conditions. The pseudo code of the algorithm is as follows: Figure 4 As shown, 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 The distance of all nodes is initialized to infinity, except for the source node s i , whose 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 adds an edge from the ground station to the target node dst. Output returns a set of candidate paths to all source nodes Then calculate the joint degree and survival time of each path. Combine the joint degree and survival time to get 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 cause bandwidth competition or congestion. In the network, avoiding sharing too many links between paths can reduce this competition and improve the data transmission efficiency of the network. 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, represents the path survival time of the first transit satellite node, represents the path survival time of the second relay satellite node, represents the path survival time of the k-th transit satellite node, is the 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 joint degree. The longer the path survival time and the lower the joint degree, the higher the priority. Therefore, when selecting a path, the path with a longer survival time and a lower joint degree will be 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, and the union degree of each path, that is, the degree of overlap between the paths, and the survival time, that is, the time that the path can remain stable, are calculated at the same time. The path with the highest priority is used as the optimal path, thereby improving data transmission efficiency.

[0071] In an optional embodiment, the bandwidth resources are allocated according to the priority of the source satellite tasks. Each source satellite will get a total bandwidth, and then each source satellite will have multiple paths for data transmission. The bandwidth of each source satellite is evenly allocated to the selected transmission path, so that time-sensitive tasks can be processed faster. 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] Where 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] In the formula, 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 on 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 abnormal situation is encountered during the transmission process, including link disconnection; data loss; node failure, that is, hardware failure of the satellite or ground station may occur, causing it to fail to work properly; signal interference, that is, external factors including solar storms and electromagnetic interference cause the quality of the communication link to decline; traffic congestion, that is, in certain hot spots or time periods, multiple satellites try to transmit a large amount of data through the same link at the same time, causing network congestion; time synchronization problem, that is, due to the high-speed movement of the satellite, if the time between the nodes is not synchronized, it may cause problems such as disordered data packet order; software error, that is, there may be problems with the software on the satellite or ground station, affecting normal data processing and forwarding. The system will automatically take corresponding recovery measures, including rescheduling data flow; switching to alternative paths; retransmission mechanism, that is, for lost data packets, the automatic retransmission request mechanism is enabled to ensure that the receiving end can receive all data completely. If the packet loss is caused by a short link interruption, partial retransmission can be performed after the link is restored instead of full retransmission; intelligent routing adjustment, that is, real-time monitoring of the network status, once an abnormality is detected, a new routing calculation is immediately started, the optimal path is replanned, and for failed nodes or links, it is quickly removed from the routing table and an alternative path is found.

[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 Embodiment 1. Figure 6 , which is an architecture diagram of the scheduling optimization system for multi-link data transmission of an earth observation satellite according to the present embodiment.

[0085] The present embodiment provides 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 is used to obtain a path indicator of a subflow, a subflow data rate, and a data transmission time of a source node according to 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] The shortest path selection module is used to obtain the shortest path set from the source node to the destination node by combining the path indicator, the data rate of the sub-flow, and the data transmission time of the source node with the bandwidth constraint and the data volume constraint, with the minimization of the total data transmission time as the optimization goal;

[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 repeatedly here.

[0092] Example 3

[0093] This embodiment proposes a computer device, including a memory and a processor, wherein the memory stores computer-readable instructions, and 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 to 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; 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.

2. The scheduling optimization method for multi-link data transmission of an earth observation satellite according to claim 1, characterized in that: 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 scheduling optimization method for multi-link data transmission of an earth observation satellite according to claim 1, characterized in that: 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 shortest path set from the source satellite to each target ground station within the static duration; wherein 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: In the formula, 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 scheduling optimization method for multi-link data transmission of an earth observation satellite according to claim 1, characterized in that: 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 and create a distance dictionary, and initialize the distances 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 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 then calculate the joint degree and survival time of each path; The priority is calculated by combining the joint degree and the survival time, and the path with the highest priority is taken as the optimal path.

5. The scheduling optimization method for multi-link data transmission of an earth observation satellite according to claim 4, characterized in that: The path union degree is defined as the overlap degree 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, represents the path survival time of the first transit satellite node, represents the path survival time of the second relay satellite node, Represents the path survival time of the k-th transit satellite node.

6. The scheduling optimization method for multi-link data transmission of an earth observation satellite according to claim 4, characterized in that: The combining of the joint degree and the survival time to calculate the priority includes calculating the ratio of the 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.

7. The scheduling optimization method for multi-link data transmission of an earth observation satellite according to claim 1, characterized in that: The method of allocating bandwidth resources according to the priority of the source satellite missions and evenly allocating 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: In the formula, 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 bandwidth and 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 allocated to the selected transmission path; the expression is: Where b p Indicates the bandwidth on each data transmission path, Indicates the path number of the source satellite.

8. The method for scheduling and optimizing multi-link data transmission of an earth observation satellite according to claim 1, characterized in that: 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 in the network topology are detected, the optimal path is recalculated and the bandwidth is reallocated to adjust the data transmission path.

9. A scheduling optimization system for multi-link data transmission of an earth observation satellite, using the scheduling optimization method for multi-link data transmission of an earth observation satellite according to any one of claims 1 to 8, 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 is used to obtain a path indicator of a subflow, a subflow data rate, and a data transmission time of a source node according to 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; The shortest path selection module is used to obtain the shortest path set from the source node to the destination node by combining the path indicator, the data rate of the sub-flow, and the data transmission time of the source node with the bandwidth constraint and the data volume constraint, with the minimization of the total data transmission time as the optimization goal; 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.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the scheduling optimization method for multi-link data transmission of an earth observation satellite as described in any one of claims 1 to 8 is implemented.

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