# SatScope: A Data-Driven Simulator for Low-Earth-Orbit Satellite Internet
## 1 Introduction  
The LEO satellite internet leverages satellite communication to achieve extensive coverage, offering unique connectivity services especially in remote and underserved regions. The rapid advancements in reusable rockets, miniaturized satellites, and link-tracking technologies have propelled LEO satellite internet towards maturity, positioning it as a popular alternative for network access beyond traditional fixed connections and wireless systems. Commercial initiatives such as Starlink have significantly promoted the adoption of LEO satellite internet [1]; however, this domain still faces challenges related to limited spectrum resources and space debris.  
Unlike geostationary orbit communications, LEO satellite internet excels in low propagation latency and resilience against physical damage, yet it introduces new challenges like satellite tracking and precise location determination, along with the formation of robust satellite-to-satellite links. Compared to terrestrial networks, LEO satellite networks are highly sensitive to latency, which can impede the stable operation of latency-sensitive applications such as live video streaming.  
Given the complexity of the space environment, current research on optimizing LEO satellite internet systems predominantly relies on simulation [2; 3; 4; 5; 6]. Most LEO satellite internet simulations focus on managing satellite beams [7; 8], frequency resources [9; 10], edge network resources [11; 12], signal tracking [13; 14] and network cascading effects [15; 16] in the space segment but pay less attention to the dynamic structure of space-to-ground networks. This paper introduces SatScope, a simulation method that emphasizes the dynamic changes in LEO satellite internet. SatScope aims to provide researchers with a data-driven simulator to gain deeper insights into the spatiotemporal characteristics of LEO satellite networks.  
SatScope achieves its simulation of Starlink through the following methods: Firstly, it utilizes publicly available Two-Line Element (TLE) data from Starlink to model and simulate the space segment of satellites. Secondly, active network measurements are conducted on Starlink end-user devices to collect empirical network data, which are used to model and simulate ground equipment. Thirdly, satellite-to-ground links are established between satellites and ground stations, integrating both space and ground segments. This integration allows for the configuration of satellite topology models, routing algorithms, and load balancing schemes. Finally, traffic generation is based on real-time platform measurement data, ensuring that the simulation accurately reflects the scheduling characteristics of Starlink's LEO satellite internet.  
In Section 2, we review the related work. In Section 3, we offer a detailed introduction to the construction of the SatScope simulator. We evaluate the overall performance of SatScope in Section 4. Additionally, we present two application scenarios of SatScope in Section 5. Finally, in Section 6, we summarize this paper and outline potential directions for future research.