【作者】 杨光；

【导师】 尤力； 徐贵州；

【作者基本信息】 东南大学 ， 通信工程（专业学位）， 2024， 硕士

【摘要】 近年来,低轨巨型星座因其低延迟、高带宽、广泛覆盖和快速部署等特点,成为全球空间战略资源竞争的“新战场”。由于卫星数量的增加以及低轨轨道相比其他轨道更高的切换需求,星地可通信时间随之降低,导致卫星与地面站之间的馈电链路切换将变得更为频繁,卫星的负载压力显著增大。另一方面,动态变化的卫星业务需求对馈电链路切换提出了新的要求。本论文围绕低轨巨型星座的馈电链路切换策略展开研究。具体研究内容如下:首先,研究了低轨巨型星座网络中的链路切换策略。概述了卫星网络中卫星轨道和卫星链路等关键要素。回顾了卫星通信中链路切换等关键技术,并对低轨巨型星座的发展现状及链路切换技术进行了阐述。进一步地,基于美国太空探索技术公司Space X的数据,指出其卫星部署与地面站布局并不匹配的问题,并得出轨道高度与馈电链路切换频率的关系。数据分析结果表明:馈电链路在低轨巨型星座下需要更频繁的切换。其次,研究了低轨巨型星座的馈电链路切换策略。回顾并评估了最短距离、最长可视时间以及最强传输信号等经典切换策略。给出了链路预算中载干噪比的计算方法。在此基础上,融合多种链路评价指标,提出一种新型馈电链路切换策略。借助STK(Satellite Tool Kit)仿真平台,构建了低轨巨型星座馈电链路切换策略仿真平台,并利用STK所提供的精确星历数据,对所提新型切换策略和经典切换策略进行了对比。仿真结果表明:所提出的新型切换策略在切换次数、可通信时间及卫星负载等关键性能指标方面展现出明显优势。最后,研究了低轨巨型星座在动态业务需求场景下的馈电链路切换策略。针对具有动态业务需求的馈电链路,提出一种动态性评估模型,并搭建了可视化平台对其进行仿真测试。测试结果表明,该模型能支持不同馈电链路切换策略,并能生成一系列关键的馈电链路性能指标。进一步地,利用STK仿真平台,在卫星的动态业务需求场景下,对所提新型切换策略和经典切换策略进行了对比。仿真结果表明:新型切换策略不但适用于具有卫星动态业务量需求场景的低轨巨型星座中,而且有效提升了切换次数、可通信时间、卫星负载及业务容量等链路指标性能。更多还原

【Abstract】 In recent years,low Earth orbit(LEO)mega-constellations have emerged as a“new battleground”in the global competition for strategic space resources,owing to their advantages of low latency,high bandwidth,extensive coverage,and swift deployment.The increasing numbers of satellites and ground stations lead to more frequent feeder link switches between satellites and ground stations.This not only shortens the communication time but also significantly elevates the load on satellites.Moreover,the dynamic shifts in satellite operational demands necessitate new feeder link switching approaches.Research into feeder link switching strategies for LEO mega-constellations is currently in progress,with the following areas of focus:Firstly,this study explores the link switching strategies within the LEO mega-constellation network.It provides an overview of essential aspects such as satellite orbits and links within satellite networks.It reviews key technologies in satellite communication,including link switching,and discusses the current state and technological advancements in LEO mega-constellations.Additionally,leveraging data from Space X,a leader in space exploration technologies,this research highlights the misalignment between satellite deployment and ground station layouts and establishes the correlation between orbital altitude and feeder link switching frequency.Simulation outcomes suggest an increased necessity for frequent switching within LEO mega-constellations.The results of the data analysis indicate that the feeder link requires more frequent switching under the low-orbit mega constellation.Secondly,the study delves into the feeder link switching strategies specific to LEO mega-constellations.Classic switching strategies such as shortest distance,longest visible time,and strongest transmission sig-nal are reviewed and evaluated.The calculation method for the carrier-to-noise ratio in the link budget is provided in the article.Building on prior research,a novel feeder link switching strategy that amalgamates multiple link evaluation metrics is proposed.Utilizing the STK(Satellite Tool Kit)simulation platform to model LEO mega-constellations,the study compares the innovative strategy with conventional approaches.The findings indicate that the new strategy significantly outperforms traditional methods in key performance metrics,including switching frequency,communication time,and satellite load.Finally,the research investigates feeder link switching strategies within dynamic operational demand scenarios for LEO mega-constellations.It proposes a dynamic evaluation model for feeder links that adapt to changing operational demands and develops a simulation testing visualization platform.Test outcomes demonstrate the model’s capability to support various switching strategies and produce essential performance metrics for feeder links.Furthermore,employing the STK platform for simulations,the study contrasts the new switching strategy against traditional methods in scenarios with dynamic satellite traffic demand.The results affirm that the novel strategy not only suits LEO mega-constellations facing fluctuating traffic demands but also markedly enhances link performance metrics,including switching frequency,communication time,satellite load,and operational capacity.更多还原