# SatScope: A Data-Driven Simulator for Low-Earth-Orbit Satellite Internet
## 2 Research Status
### Research on Network Measurement  
Previous research on LEO satellites [26; 27] has demonstrated that rapid changes in network topology can severely impact the stability of the Border Gateway Protocol (BGP), leading to frequent BGP message updates. To mitigate this issue, Starlink consolidates all ground segment assets under a single autonomous system (AS) and connects its satellite network to the terrestrial internet via several Points of Presence (PoPs). This approach streamlines the process of determining destination address sets for network measurement once the AS affiliation is established, thereby facilitating large-scale stateless asynchronous measurement.  
Current satellite network measurement studies can be categorized into two main types based on their objectives: The first type of research approaches from the user perspective, analyzing metrics such as latency, throughput, and packet loss rate to identify key factors affecting satellite network performance. [PERSON] et al. [28] conducted periodic tests to evaluate throughput, latency, packet loss, and routing while recording weather data, highlighting the significant impact of rainfall on satellite communications. [PERSON] et al. [29] not only measured Starlink's network performance but also tested high-latency-sensitive services like Zoom meetings and cloud gaming between two advantageous locations. [PERSON] et al. [30] developed an online platform to aggregate user-contributed data, amassing nearly 1.7 million measurements from 309 users across 29 countries. [PERSON] et al. [31] and [PERSON], [PERSON] et al. [32] performed coarse-grained network measurements on Starlink. The former study, involving 28 volunteers, identified severe periodic packet loss and recommended improvements for satellite handover and congestion control, while the latter compared LEO, GEO, and fixed-fiber internet access, finding LEO to be less stable. [PERSON] et al. [33] carried out mobile measurements of Starlink and cellular networks across the Arctic Circle, quantifying Starlink's throughput characteristics, the impact of the 15 s reconfiguration interval, and satellite visibility, while exploring their complementarity with cellular networks. [PERSON] et al. [34] developed an autonomous system for continuous measurements and evaluated it in German urban environments for two months, revealing significant decreases in download and upload speeds during movement. [PERSON] et al. [35] performed Starlink network-layer measurements, evaluating throughput variations across multiple timescales and uncovering a 1.33 ms frame timing, offering crucial insights for satellite network performance optimization and system design.  
The second type of work involves analyzing the satellite network structure and end-user access schemes through satellite network measurements [36; 37]. [PERSON] et al. [38] conducted ongoing measurements of Starlink's internal backbone structure, providing insights into the architecture of satellite internet. [PERSON] et al. [39] analyzed the algorithms used by Starlink for selecting user-access satellites based on network measurements. [PERSON] et al. [40] introduced LEO-HitchHiking, a tool for measuring LEO satellite internet using Censys, comparing the latency of ground station relays versus satellite relays.  
Starlink engineers have made significant strides in reducing latency by leveraging millions of measurements from Starlink routers [41]. This work suggests a promising approach: integrating real-world measurement data from existing satellite network equipment into simulation models to advance research on optimizing satellite network performance.