AVANÇOS EM SISTEMAS DE SATÉLITES EM BAIXA ÓRBITA: PROTOCOLOS DE COMUNICAÇÃO, NAVEGAÇÃO E APRENDIZADO FEDERADO

This article presents a systematic review of recent advancements in Low Earth Orbit (LEO) satellite systems, focusing on three main areas: communication protocols, navigation solutions, and decentralized federated learning. The review was conducted through searches in well-established databases such as IEEE Xplore, SpringerLink, and ScienceDirect, covering publications from 2023 and 2024. The methodological process followed defined steps, including article selection based on specific keywords and the application of temporal filters to ensure relevance and up-to-date information. This survey aims to address fundamental questions: What solutions exist to reduce latency and enhance scalability in LEO networks? How can opportunity signals improve navigation accuracy in urban environments? How can decentralized federated learning be applied to optimize computational resource utilization in satellite constellations? The reviewed results highlight that regenerative architectures based on 3GPP standards, navigation systems using opportunity signals, and federated learning frameworks such as FedLEO offer promising solutions while still presenting challenges like frequent handovers and bandwidth limitations. This study provides a solid foundation for future research and development, with potential impacts on telecommunications, IoT, and disaster response. Keywords: Low Earth Orbit satellites, Communication protocols, Navigation, Federated learning.