# SatScope: A Data-Driven Simulator for Low-Earth-Orbit Satellite Internet
## 2 Research Status
### Research on Simulators  
To enhance the communication quality for users of LEO satellite internet and improve overall network stability, researchers have evaluated delay-tolerant routing and load-balancing strategies within simulation environments. [PERSON] et al. [22] developed Hypatia, a simulator built on the NS3 extension modules and the pyephem library. Hypatia imports TLE data to construct satellite models and simulate packet transmission over discrete static topologies. The study focused on the 100 most populous cities as ground terminals, analyzing fluctuations in inter-satellite laser link utilization under the +Grid architecture. [PERSON], [PERSON] et al. [4] integrated STK 11 [2] and MATLAB 2013b to create StarPerf, a non-discrete time simulator based on idealized satellite models derived from reported parameters such as altitude and inclination for Starlink and OneWeb constellations. StarPerf optimizes relay selection algorithms by selecting specific cities as ground terminals. In a subsequent work, [PERSON], [PERSON] et al. [5] introduced STARRYNET, which employs a digital twin environment to simulate large-scale integrated space-ground networks. This approach requires substantial computational resources and real-time data synchronization, thereby increasing experimental costs. [PERSON] et al. [6] developed Plotinus, a digital twin system for satellite networks that offers sophisticated physical modeling of satellite terminals. Building upon idealized satellite models, Plotinus uses digital twin technology to model  
Figure 1: Diagram of satellite internet operating mechanism. Terminal users from around the world access the LEO satellite internet by connecting to satellites, which function as data relays in the satellite communication network.  
and analyze antenna array gains, beam interference, and channel capacity at the physical layer. [PERSON], [PERSON] et al. [23] also leveraged STK and MATLAB, using parameters like altitude and inclination from Iridium and Celestri satellites to generate satellite models. They proposed SPDA, a method for static placement and dynamic allocation that addresses the placement of Software-Defined Networking controllers in LEO satellite networks. [PERSON] et al. [24] developed LeoEM, a real-time simulator for LEO satellite networks, and designed the SATCP cross-layer mechanism. By predicting satellite handover events to optimize TCP congestion control, they enhanced LEO satellite network performance. [PERSON] et al. [25] presented an efficient topology partitioning algorithm for system-level parallel simulation of mega-constellation communication networks. They built a parallel simulation architecture using STK, OPNET, and Proxmox VE, greatly improving simulation efficiency. Also, they optimized simulation resource allocation via a resource evaluation algorithm and a Load-Balanced Topology Partitioning algorithm.  
In simulation environments, using real-time satellite data from TLE for LEO satellite internet presents two key factors that influence fidelity:  
* Lack of Focus on Ground Segment User Distribution: Research on satellite networks predominantly emphasizes the performance of communications between space segment assets and major cities, lacking detailed granularity down to the user level. The distribution of different ground terminal users significantly impacts network configuration and strategy optimization.
* Insufficient Support for Ground Station Distribution: In various studies related to satellite networks, the locations of ground stations are generated according to specific rules. However, these rules fail to account comprehensively for complex factors such as economic development, regional culture, and regulatory policies, thereby reducing the fidelity of the simulations.  
Recent advancements in LEO satellite internet have notably progressed in optimizing satellite communication systems from a network measurement perspective, particularly focusing on the ground segment.