Simulation and Comparison of Vehicle Satellite Connectivity under a 3D Foliage Environment: Starlink and OneWeb

Satellite communication for mobility use-cases is emerging as a key market for low-Earth orbit satellite constellations, offering broadband internet with sufficiently low latency in regions lacking terrestrial coverage. A commonly overlooked challenge in these scenarios is dynamic blockage caused by dense foliage or complex topography, where a line-of-sight satellite link can be difficult to establish. This work introduces a simulation framework to estimate key performance indicators for given constellation designs in a 3D geospatial environment comprising natural and build features. We demonstrate the simulator in a selected 3D scenario, showcase its capabilities, and compare the performance of two commercially active mega-constellations in delivering broadband connectivity under these conditions.

面向移动应用场景的卫星通信正成为低地球轨道（LEO）卫星星座的一个关键新兴市场，它能在缺乏地面网络覆盖的地区提供延迟足够低的宽带互联网服务。在此类场景中，一个常被忽视的挑战是由茂密植被或复杂地形引起的动态阻塞，导致难以建立视距（Line-of-Sight, LoS）卫星链路。本研究引入了一个仿真框架，用于在包含自然和人造地物的3D地理空间环境中，评估给定星座设计的关键性能指标（Key Performance Indicators, KPIs）。我们在一个选定的3D场景中对该仿真器进行了演示，展示了其各项功能，并比较了两个已商业运营的巨型星座在此类条件下提供宽带连接的性能。

Introduction

In recent years, the launch and adoption of satellite systems in Low Earth Orbit (LEO) as communication payloads for broadband internet have had unprecedented effects on the satellite communication (SATCOM) ecosystem [1]. With the privatization of this sector by players such as Starlink, OneWeb, and Amazon Kuiper, a new gold rush for the “Internet from Space” has emerged. What began as a vision to provide internet access to underserved and remote regions has evolved into a multifaceted commercial model, extending far beyond the original humanitarian intent. Today, active developments and deployments target a broad range of use cases, including direct-to-device connectivity, governmental and defense applications, and mobility scenarios such as aviation, maritime, and automotive integration [2].

These advancements, together with cheaper launches and manufacturing processes, have enabled more agile and applicationspecific system design concepts [3]. Among the industries exploring SATCOM as a strategic asset, the automotive sector plays an increasingly important role, with growing interest driven by the need for reliable broadband connectivity to support infotainment, over-the-air updates, vehicle-to-cloud (V2X) communication, and autonomous driving functions [4]. As such, the integration of NonTerrestrial Networks (NTNs) is emerging as an indispensable opportunity to enhance future automotive connectivity.

However, one critical challenge remains sparsely addressed: the highly dynamic and unpredictable propagation environment of automotive platforms. As illustrated in Figure 1, even small changes in vehicle position or orientation can cause severe signal degradation due to terrain or foliage obstructing the line-of-sight (LOS) to the satellite. While uninterrupted LOS is essential for broadbandlevel throughput in state-of-the-art LEO constellations, such conditions are rarely sustained in real-world automotive scenarios. Although other obstructions, such as man-made structures, can also impair SATCOM performance, this work focuses on vegetation- and terrain-related attenuation, as these are particularly prevalent in rural regions where NTNs are envisioned to complement terrestrial networks. Despite its relevance, vegetation-induced attenuation in LEO SATCOM remains insufficiently addressed in current literature, leaving a significant gap in understanding its impact on mobile SATCOM reliability.

To address this gap, we present a modular simulation framework that integrates 3D terrain and foliage environments to assess the performance of LEO SATCOM in vehicle mobility scenarios.

The remainder of the paper is structured as follows. Section 2 provides an overview of related work on foliage attenuation in SATCOM links and existing simulation platforms. Section 3 presents the proposed simulation framework, including the integration of a 3D foliage environment and the introduction of key simulation parameters. In Section 4, we present and discuss results for two representative satellite constellations. Finally, Section 5 outlines current limitations and directions for future work on the simulation framework.

近年来，低地球轨道（Low Earth Orbit, LEO）卫星系统作为宽带互联网的通信载荷，其发射与应用对卫星通信（SATCOM）生态系统产生了前所未有的影响[1]。随着Starlink、OneWeb和亚马逊Kuiper等公司推动该领域的私有化，“太空互联网”的新一轮淘金热已经兴起。最初旨在为服务欠缺及偏远地区提供互联网接入的愿景，现已演变为一个多层面的商业模式，其范围远超最初的人道主义初衷。如今，活跃的研发与部署已面向广泛的应用场景，包括直连终端设备、政府与国防应用，以及航空、海事和汽车集成等移动场景[2]。

这些技术进步，加之发射与制造成本的降低，催生了更敏捷且面向特定应用的系统设计理念[3]。在众多将卫星通信视为战略资产的行业中，汽车行业扮演着愈发重要的角色。为了支持信息娱乐、空中下载（Over-the-Air, OTA）更新、车云通信（V2X）以及自动驾驶功能，汽车行业对可靠宽带连接的需求日益增长，从而激发了对卫星通信的浓厚兴趣[4]。因此，集成非地面网络（Non-Terrestrial Networks, NTNs）正成为增强未来汽车连接性不可或缺的机遇。

然而，一个关键挑战的研究尚不充分：汽车平台所处的高度动态且不可预测的传播环境

如图1所示，车辆位置或姿态的微小变化都可能因地形或植被遮挡卫星视距（Line-of-Sight, LOS）而导致严重的信号衰减。

对于最先进的LEO星座而言，不间断的LOS是保证宽带级数据吞吐量的必要条件，但在真实的汽车应用场景中，这种条件却鲜能持续满足。

尽管建筑物等人造障碍物同样会影响卫星通信性能，但本研究聚焦于由植被和地形引起的衰减，因为这些因素在非地面网络旨在补充地面网络的广大农村地区尤为普遍。尽管植被引起的衰减问题至关重要，但在当前的LEO卫星通信文献中仍未得到充分探讨，这在理解其对移动卫星通信可靠性的影响方面留下了显著的研究空白。

为填补这一空白，我们提出了一个模块化的仿真框架，该框架集成了三维地形与植被环境，用以评估LEO卫星通信在车载移动场景下的性能。

本文的其余部分结构如下。第2节概述了卫星通信链路中植被衰减的相关研究工作及现有的仿真平台。第3节介绍了我们提出的仿真框架，包括三维植被环境的集成和关键仿真参数的引入。在第4节中，我们展示并讨论了两个代表性卫星星座的仿真结果。最后，第5节总结了该仿真框架当前的局限性及未来的工作方向。

Related Work

Foliage attenuation in SATCOM has a well-established research history. [5] proposed a simple model between 8 GHz-18 GHz to characterize attenuation from individual trees in satellite-to-mobile scenarios, identifying two diffraction zones around the trunk and the crown. Similarly, [6] presented Ku-band measurement data for land-mobile links, analyzing cumulative attenuation distributions across varying slant path angles. The ITU provides standardized models for vegetation-induced attenuation in radiowave propagation, covering multiple vegetation types and geometric configurations, including slant path scenarios in SATCOM [7].

Simulators have been central to evaluate LEO satellite systems. A range of open-source and commercial tools support system-level design, performance analysis, and network evaluation. MATLAB and STK are frequently used for end-to-end simulations, while tools like ns-3 and OMNeT++ enable network-layer modeling [8]. Notably, [9] employed ns-3 to develop “Hypatia,” a network simulator for dynamic inter-satellite link topologies, highlighting the challenges LEO constellations pose for routing and traffic management. In the automotive domain, research has focused on traffic management, Vehicle-to-Vehicle (V2V) communication, and autonomous driving. SUMO enables large-scale simulations of vehicular and pedestrian flows with V2V and demand modeling, while CARLA supports development and validation of autonomous driving systems in customizable 3D urban environments [10, 11].

However, integrated simulation frameworks that combine dynamic LEO constellations with time-varying terrestrial channel environments remain poorly understood. To the authors’ knowledge, no existing studies model LEO satellite communication performance within detailed 3D foliage environments.

卫星通信中的 植被衰减 已有完善的研究历史。[5] 提出了一个适用于 8 GHz-18 GHz 频段的简化模型，用于表征卫星至移动终端场景中单棵树木所造成的衰减，并识别出围绕树干和树冠的两个衍射区。类似地，[6] 提供了陆地移动链路的 Ku 波段测量数据，并分析了不同斜路径角度下的累积衰减分布。国际电信联盟（ITU）也为无线电波传播中的植被衰减提供了标准化模型，涵盖了多种植被类型和几何配置，包括卫星通信中的斜路径场景 [7]。

仿真器在评估 LEO 卫星系统中一直扮演着核心角色

一系列开源及商业工具可支持系统级设计、性能分析和网络评估:

• MATLAB 和 STK 常用于端到端仿真
• ns-3 和 OMNeT++ 等工具则支持网络层建模 [8]

值得注意的是，[9] 采用 ns-3 开发了名为 “Hypatia” 的网络仿真器，用于模拟动态的星间链路拓扑，突显了 LEO 星座在路由和流量管理方面所面临的挑战

在汽车领域，研究主要集中在交通管理、车对车（V2V）通信和自动驾驶:

• SUMO 能够对车辆与行人流进行大规模仿真，并支持 V2V 和需求建模
• CARLA 则支持在可定制的 3D 城市环境中开发和验证自动驾驶系统 [10, 11]

然而，将动态 LEO 星座与时变的地面信道环境相结合的集成化仿真框架，目前仍缺乏深入的研究。据作者所知，尚无现有研究在精细的 3D 植被环境中对 LEO 卫星通信性能进行建模。