A robust communication networking and path reconstruction method for dense low earth orbit constellation network

Abstract

The application belongs to the technical field of satellite communication, and particularly relates to a robust communication networking and path reconstruction method for a dense low-orbit constellation network, comprising a coverage analysis method and an inter-satellite networking and path reconstruction algorithm; the coverage analysis method is to first select several uniformly distributed orbit low-orbit satellites from the dense constellation, and then sample the satellites with the same function in each orbit; the inter-satellite networking and path reconstruction algorithm is to, when a satellite needs to forward remote sensing data, first forward the data to visible satellites according to the visibility, and when there are multiple visible satellites, find the communication path between the source node and the destination node in a reactive routing mode with the spatial-temporal anti-interference of the node as the weight. The application has high robustness and low time delay, and has a wide prospect in the application of massive data with low cost and fast response.

Description

Technical Field

[0001] This invention belongs to the field of satellite communication technology, specifically relating to a robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks. Background Technology

[0002] With the rapid development of remote sensing and telemetry technologies, the scale of image data such as video and photos has exploded. However, traditional remote sensing systems use complex and independent subsystems to process and distribute data, which is difficult to meet users' needs for real-time acquisition of remote sensing information. In recent years, low-Earth orbit (LEO) communication networks have received widespread attention due to their advantages such as wide coverage, all-weather operation, and fast response. LEO commercial constellations, represented by Starlink, OneWeb, and Hongyan, have entered or are planned to be deployed on a large scale, becoming the key to real-time transmission of massive amounts of data. However, due to the short overhead time of low-Earth orbit satellites and the dynamic changes in satellite network topology, when remote sensing satellites transmit acquired data to visible communication satellites at the current moment, real-time data delivery often requires technologies such as inter-satellite networking and task distribution. In this case, reliable inter-satellite links are crucial for real-time transmission; however, interference-induced link interruptions are widespread during transmission. Consequently, remote sensing data is often lost during relay. Meanwhile, due to the limited satellite orbit resources, how to complete the transmission of remote sensing data using the fewest possible satellites while ensuring fast response transmission is also a major challenge.

[0003] To address the aforementioned challenges, this invention proposes a robust communication networking and path reconstruction method for dense low-Earth orbit constellations to solve the problem of distributing massive amounts of remote sensing data in interference scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide a robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks, which has high robustness and low latency, and has broad prospects in low-cost, fast-response massive data applications.

[0005] The specific technical solution adopted by this invention is as follows: A robust communication networking and path reconstruction method for dense low-Earth orbit constellations, including a coverage analysis method and an inter-satellite networking and path reconstruction algorithm; The coverage analysis method involves first selecting a few low-Earth orbit satellites that are evenly distributed in a dense constellation, and then sampling satellites with the same function in each orbit. The inter-satellite networking and path reconstruction algorithm is as follows: when a satellite needs to forward remote sensing data, it first forwards the data to the visible satellite based on visibility. When there are multiple visible satellites, it uses the spatiotemporal anti-interference ability of the nodes as weights and uses a reactive routing method to find the communication path between the source node and the destination node.

[0006] Furthermore, the inter-satellite networking and path reconstruction algorithm includes the following steps: S1: In the algorithm initialization phase, a time-varying graph of the network topology of visible stars is constructed under different interference levels to characterize the network features; S2: Based on the time-varying graph of network topology, the source node sends a routing request message, which prompts the source node to simultaneously search for all available routes to the destination node and find the most stable route and the backup route. S3: The destination node sends a routing response message. After receiving the response message, the node compares the weight in the response message with the weight of the neighboring node that sent the response message relative to itself, and updates the routing weight. S4: Route selection. Select the path with the highest weight in the link as the satellite data forwarding route.

[0007] Further, S1 includes the following steps: S101: Convert the time-varying graph (TVG) into a line graph (LG), realizing the conversion from a dynamic topology model to a static topology model; S102: Based on the conventional line graph, the node information maintained by the line graph is improved by weighting the spatiotemporal anti-interference ability of the nodes.

[0008] Further, S2 includes the following steps: During data forwarding, if a relay node receives this request information for the first time, it records the weight of its reverse route and then forwards the request information. If a relay node receives the same request from different upstream nodes, it compares the weights with the weights stored locally and updates the routing weights.

[0009] Further, S3 includes the following steps: When a node receives the first response to this routing request, it treats it as a temporary path for communication, records its weight and hop count, and continues to receive other response information. If the weight of the subsequent response information is greater and the number of hops is no greater than that of the previous path, the service will be switched to this path; otherwise, it will be stored as a backup in the routing table. If the node is a relay node, then after updating the path weight, the response information with a weight greater than the current route weight will be forwarded; The destination node responds to the same response message from all different previous hop nodes, returning the response message, but the relay node only forwards the same response message once.

[0010] The technical effects achieved by this invention are as follows: The present invention provides a robust communication networking and path reconstruction method for dense low-Earth orbit constellation networks. Based on satellite coverage, it analyzes the impact of different interference levels and utilizes the spatiotemporal characteristics of constellation network topology changes to construct a time-varying map to complete satellite networking and data transmission. It has high robustness and low latency, and has broad prospects in low-cost, fast-response massive data applications. Attached Figure Description

[0011] Figure 1 This is a three-dimensional schematic diagram of the dense low-orbit constellation network of the present invention; Figure 2 This is a schematic diagram of the non-sampling plane of the satellite network of the present invention; Figure 3 This is a schematic diagram of the sampling plane of satellite network 2 of the present invention; Figure 4 This is a flowchart of the communication networking and path reconstruction algorithm of the present invention; Figure 5 This is a schematic diagram illustrating how the communication networking and path reconstruction algorithm of this invention transforms the network topology into a time-varying graph; Figure 6(a) shows the coverage performance of the dense low-orbit constellation network of the present invention over a certain area without sampling. Figure 6(b) is a diagram showing the coverage performance of the dense low-orbit constellation network over a certain area during sampling according to the present invention 2. Figure 6(c) is a diagram showing the coverage performance of the dense low-orbit constellation network over a certain area during the third sampling of this invention. Figure 6(d) is a diagram showing the coverage performance of the dense low-orbit constellation network over a certain area during the 4th sampling of this invention; Figure 7 Performance chart of invisible grid interruption time percentage for dense low-Earth orbit constellation network under different sampling conditions; Figure 8 The communication networking and path reconstruction algorithm of this invention can achieve a path number graph under an interference probability of 50%. Detailed Implementation

[0012] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0013] Example 1:

[0014] like Figure 1-8As shown, this technical solution is based on the topology of an on-orbit commercial satellite constellation network. Taking into account factors such as constellation coverage, transmission latency, and construction costs, it utilizes existing satellite communication protocols to achieve real-time response and backhaul of massive amounts of data in remote sensing and defense applications. It includes two parts: coverage analysis and inter-satellite networking and path reconstruction schemes. Based on satellite coverage, it analyzes the impact of different interference levels and utilizes the spatiotemporal characteristics of constellation network topology changes to construct time-varying maps to complete satellite networking and data transmission. It is applicable to scenarios in remote sensing and defense applications such as meteorological monitoring, marine communication, and emergency rescue where massive amounts of data need to be transmitted in real time. The coverage analysis method is as follows: In a dense constellation network, to fully utilize satellite capacity and increase the utilization rate of orbital resources, and while meeting latency performance requirements, the goal is to use as few satellites as possible in the transmission process. Therefore, this invention first selects several evenly distributed low-Earth orbit satellites from the dense constellation, and then samples satellites with the same function within each orbit. This ensures that the performance before and after sampling does not change significantly, thereby reducing the number of satellites involved in transmission and the complexity of the system algorithm. The sampling process is as follows: Figures 2-3 As shown. This invention patent utilizes STK simulation software to analyze the coverage performance of this dense constellation network under 2-sampling, 3-sampling, 4-sampling, and no-sampling conditions.

[0015] The inter-satellite networking and path reconstruction algorithms are as follows: The inter-satellite networking and path reconstruction algorithm of this invention is based on satellite visibility. When a satellite needs to forward remote sensing data, it first forwards the data to the visible satellites based on visibility. When multiple visible satellites exist, the spatiotemporal anti-interference ability of the nodes is used as the weight, that is, the directed edges and lengths of the time-varying graph are constructed based on the visibility duration and inter-satellite distance. The communication path between the source node and the destination node is found using a reactive routing method. The main body of the algorithm is divided into three stages: algorithm initialization, the source node sending routing request information (RREQ), and the destination node sending routing response information (RREP). The entire process is as follows: Figure 4 As shown; like Figure 1 As shown, an inter-satellite networking and path reconstruction algorithm includes the following steps: S1: In the algorithm initialization phase, a time-varying graph of the network topology of visible stars is constructed under different interference levels to characterize the network features; In this stage, S1 includes the following steps: S101: Convert the time-varying graph TVG into a line graph LG, realize the conversion from dynamic topology model to static topology model, and more intuitively represent the connection relationship of each edge in the network while retaining the reachability information of TVG, and maintain the connection relationship in the nodes of the line graph; Here, in the process of converting the time-varying graph TVG to the line graph LG, the time-varying characteristics of TVG are preserved in order to take into account the analysis of network time characteristics. S102: Based on the conventional line graph, the node information maintained by the line graph is improved by using the spatiotemporal anti-interference ability of the nodes as weights. This involves constructing the directed edges and lengths of the time-varying graph using the visible duration and inter-satellite distances. The process is as follows: Figure 5 As shown.

[0016] S2: Based on the time-varying graph of network topology, the source node sends a route request message (RREQ) to find the most stable route and improve the stability of the transmission path, and to provide backup routes and enhance the anti-interference capability of the transmission. This allows the source node to find all available routes to the destination node at the same time. Specifically, S2 includes the following steps: During data forwarding, if a relay node receives the request information for the first time, it records the weight of its reverse route and then forwards the request information. If a relay node receives the same request from different upstream nodes, it compares the weights with the weights stored locally and updates the routing weights.

[0017] S3: The destination node sends a route response information (RREP). After receiving the response information, the node compares the weight in the response information with the weight of the neighboring node that sent the response information relative to itself, and updates the route weight. The routing weight is the minimum value of the link weight; Specifically, S3 includes the following steps: When a node receives the first response to this routing request, it treats it as a temporary path for communication, records its weight and hop count, and continues to receive other response information. If the weight of the subsequent response information is greater and the number of hops is no greater than that of the previous path, the service will be switched to this path; otherwise, it will be stored as a backup in the routing table. If the node is a relay node, then after updating the path weight, the response information with a weight greater than the current route weight will be forwarded; The destination node responds to the same response message from all different previous hop nodes, returning the response message, but the relay node only forwards the same response message once to avoid loops.

[0018] S4: Route selection. Select the path with the highest weight in the link as the satellite data forwarding route.

[0019] Example 2:

[0020] This embodiment takes the Starlink mega-constellation as an example, selects 5 evenly spaced orbits for data transmission, and performs 2-sample, 3-sample, and 4-sample on each orbit; For a constellation network of 295 Starlink satellites in five orbits, Figures 6(a) to 6(d) show the real-time coverage capability of a certain area under this constellation configuration. As can be seen from the figures, when using 295 Starlink satellites, the instantaneous coverage of the area reaches more than 87.98%, and the real-time coverage can reach 100%, with no coverage interruptions.

[0021] Under the sampling conditions, the instantaneous coverage of the area reaches more than 63%, and the real-time coverage can reach 100%, while there is no coverage interruption time. Under the sampling conditions, the instantaneous coverage of the area reaches more than 50%, and the real-time coverage can reach 100%, while there is no coverage interruption time. Under the sampling conditions, the instantaneous coverage of the area reaches more than 42%, and the real-time coverage can reach 100%, while there is no coverage interruption time.

[0022] Figure 7 This chart displays the percentage of outage time for all invisible raster cells in the area. The horizontal axis represents the duration of the outage in minutes, and the vertical axis represents the percentage of raster cells with a specific outage duration. It shows that sampling with option 4 has a significant impact in this area, causing some raster cells to have an outage time of up to 16 minutes, while sampling with options 2 and 3 has a smaller impact. Therefore, to ensure coverage over a large area, sampling with options 2 and 3 should be used as much as possible.

[0023] Figure 8 The paper demonstrates the number of reachable paths for the inter-satellite networking and path reconfiguration method proposed in this invention under an interference probability of 50%. The simulation results show that the maximum number of reachable paths at different simulation times is 7. When no reachable path is found, the interruption probability is calculated to be 0.144%, which can achieve good networking performance.

[0024] The simulation results described above verify that the inter-satellite networking and path reconstruction method proposed in this invention maximizes satellite utilization while ensuring reachable paths. This demonstrates that the proposed scheme possesses high robustness and low latency, and has broad prospects in low-cost, fast-response applications involving massive amounts of data.

[0025] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks, characterized in that: This includes coverage analysis methods and inter-satellite networking and path reconstruction algorithms; The coverage analysis method involves first selecting a few low-Earth orbit satellites that are evenly distributed in a dense constellation, and then sampling satellites with the same function in each orbit. The inter-satellite networking and path reconstruction algorithm is as follows: when a satellite needs to forward remote sensing data, it first forwards the data to the visible satellite based on visibility. When there are multiple visible satellites, it uses the spatiotemporal anti-interference ability of the nodes as the weight and uses a reactive routing method to find the communication path between the source node and the destination node. The inter-satellite networking and path reconstruction algorithm includes the following steps: S1: In the algorithm initialization phase, a time-varying graph of the network topology of visible stars is constructed under different interference levels to characterize the network features; S2: Based on the time-varying graph of network topology, the source node sends a routing request message, which prompts the source node to simultaneously search for all available routes to the destination node and find the most stable route and the backup route. S3: The destination node sends a routing response message. After receiving the response message, the node compares the weight in the response message with the weight of the neighboring node that sent the response message relative to itself, and updates the routing weight. S4: Route selection, selecting the path with the highest weight in the link as the satellite data forwarding route; S1 includes the following steps: S101: Convert the time-varying graph (TVG) into a line graph (LG), realizing the conversion from a dynamic topology model to a static topology model; S102: Based on the conventional line graph, the node information maintained by the line graph is improved by weighting the spatiotemporal anti-interference ability of the nodes; In S102, the node information is improved by constructing the directed edges and lengths of the time-varying graph based on the visibility duration and inter-satellite distance.

2. The robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks according to claim 1, characterized in that: The time-varying characteristics of TVG are preserved during the conversion from time-varying graph (TVG) to line graph (LG).

3. The robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks according to claim 1, characterized in that: S2 includes the following steps: During data forwarding, if a relay node receives this request information for the first time, it records the weight of its reverse route and then forwards the request information. If a relay node receives the same request from different upstream nodes, it compares the weights with the weights stored locally and updates the routing weights.

4. The robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks according to claim 1, characterized in that: In S3, the routing weight is taken as the minimum value of the link weight.

5. The robust communication networking and path reconfiguration method for dense low-Earth orbit constellation networks according to claim 1, characterized in that: S3 includes the following steps: When a node receives the first response to this routing request, it treats it as a temporary path for communication, records its weight and hop count, and continues to receive other response information. If the weight of the subsequent response information is greater and the number of hops is no greater than that of the previous path, the service will be switched to this path; otherwise, it will be stored as a backup in the routing table. If the node is a relay node, then after updating the path weight, the response information with a weight greater than the current route weight will be forwarded; The destination node responds to the same response message from all different previous hop nodes, returning the response message, but the relay node only forwards the same response message once.

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