# Digital Twin Technology-Based Networking Solution in Low Earth Orbit Satellite Constellations
## 7 Conclusions  
In this study, we develop a DT-enabled LEO satellite network to address the challenges of high trial-and-error costs and limited sensing capabilities. Specifically, we propose a network topology simulation method that dynamically analyzes the inter-satellite topology based on predefined ephemeris and orbit information. The proposed method allows for a deeper understanding of the structure and behavior of satellite constellations, enabling effective network design and optimization. Furthermore, we design a digital twin algorithm based on network virtualization, cloud platform management, and software-defined networking to validate and analyze the requirements of the twin system at different stages. It helps to identify potential issues and formulate optimized solutions. Finally, we construct a LEO satellite twin validation environment to verify the network protocols at various stages. Through extensive experimental evaluations, the performance of the twin system is demonstrated, showcasing its effectiveness in different scenarios.  
The foundation for the creation of digital twins of low earth orbit constellations lies in establishing a low Earth orbit constellation twin system. Two primary mature technologies for this process are network simulation and physical entity simulation. However, neither of these two approaches can simultaneously meet the requirements for full-constellation high-fidelity simulation, low-cost implementation, and comprehensive lifecycle simulation. Therefore, our study innovatively introduces advanced methods such as network function virtualization, cloud platform management, and software-defined networking into the realm of network twinning. To achieve the twinning of the low Earth orbit constellation topology, network elements within the constellation are simulated using virtualization, and the network topology is simulated through SDN control flow tables. Subsequently, the low Earth orbit constellation twinning system is constructed based on these technical methods. In our future work, we will pursue the more accurate physical modeling of satellite activities by incorporating SAR images and change detection techniques into the digital twin formation procedure and considering more detailed parameters during state sampling and reconstruction [31].  
**Author Contributions:** Formal analysis, M.Y.; Funding acquisition, Y.Z.; Methodology, J.K.; Supervision, C.C.; Writing-original draft, C.H.; Writing-review and editing, C.H. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the National Key Research and Development Program of China (2020 YFB1807500), the National Natural Science Foundation of China (62072360, 62001357, 62172438, 61901367), the key research and development plan of Shaanxi province (2021 ZDLGY02-09, 2023-GHZD-44, 2023-ZDLGY-54), the Natural Science Foundation of Guangdong Province of China (2022A1515010988), Key Project on Artificial Intelligence of Xi'an Science and Technology Plan (23 ZDCYJSGG0021-2022, 23 ZDCYYYCJ0008, 23 ZDCYJSGG0002-2023), Xi'an Science and Technology  
Figure 23: End-to-end delay change caused by abnormal interruption of inter-satellite link.  
Plan (20 RGZN0005) and the Proof-of-concept fund from Hangzhou Research Institute of Xidian University (GNYZ2023 QC0201).  
**Data Availability Statement:** Data are contained within the article.  
**Conflicts of Interest:** The authors declare no conflicts of interest.