发表机构
University of Pisa（比萨大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对分布式卫星天线的FoA架构，结合球面波与几何模型评估简化假设对吞吐量和中断概率的影响，发现局部平面波近似预编码可靠、全局近似会致中断，明确了近似适用场景。
AI 中文摘要
分布式卫星可直接向商用手机提供宽带连接。在阵列（FoA）架构中，协作卫星合成一个大孔径，其范围取决于卫星数量、排列方式和间距，星间距离从数十米到数百公里不等。对于典型的S波段地球静止轨道和低地球轨道构型，当间距约为100米时，夫琅禾费距离可能超过天底链路范围。因此，要评估不同卫星群体和间距下的FoA性能，需对处于辐射近场（即低于该阵列夫琅禾费距离）的用户采用球面波建模，还需评估卫星位置、阵列方向和用户位置的平面模型与考虑轨道和地球曲率的球面几何的匹配度。本文结合这些模型，量化简化假设对吞吐量和中断概率的影响。数值结果表明，基于每个卫星阵列内局部平面波近似的多天线预编码与球面波参考结果高度吻合；而全局平面波近似会导致严重损耗，甚至完全中断。在研究场景中，阵列曲率影响很小，而忽略地球曲率会高估低地球轨道的吞吐量。这些发现明确了几何和传播近似的可靠适用场景，并证明对于大型分布式天线孔径，空间比人们想象的近得多。
英文摘要
Distributed satellites can deliver broadband connectivity directly to commercial handsets. In the formation of arrays (FoA) architecture, cooperating satellites synthesize a large aperture whoseextent depends on their number, arrangement, and spacing, with intersatellite distances ranging from tens of meters to hundreds of kilometers. For representative S-band geostationary and low-Earth-orbit configurations, the Fraunhofer distance may exceed the nadir link range at spacings on the order of a hundred meters. Therefore, accurate assessment of FoA performance across satellite populations and spacings requires spherical-wave modeling for users in the radiative near field, below the formation's Fraunhofer distance. Planar models of satellite positions, array orientations, and user locations must also be assessed against spherical geometries accounting for orbital and Earth curvature. This paper combines these models to quantify how simplifying assumptions affect throughput and outage probability. Numerical results show that multi-antenna precoding based on a local plane-wave approximation within each satellite array closely matches the spherical-wave reference. A global plane-wave approximation can instead cause severe losses, including full outage. In the investigated scenarios, formation curvature has little impact, whereas neglecting Earth curvature overestimates low-Earth-orbit throughput. These findings clarify when geometric and propagation approximations remain reliable and demonstrate that, for large distributed antenna apertures, space is much closer than one might think.
Commentscurrently submitted to IEEE Transactions on Aerospace and Electronics Systems (14 figures, 1 table)
