Unmanned aerial vehicles (UAVs) are increasingly integrated into cellular networks to support emerging Internet of Things (IoT) applications. In such settings, reliable communication is critical for electronic conspicuity (EC), enabling UAV detection and tracking in shared airspace. However, UAVs operate at elevated altitudes where enhanced line-of-sight (LOS) visibility leads to simultaneous exposure to multiple base stations, resulting in strong inter-cell interference. This article presents a system-level analysis of how UAV altitude influences the radio environment and affects EC reliability. Using spatial and network-level metrics, including serving distance, association behavior, and aggregate received power, we show that increasing altitude leads to stronger multi-cell interaction, reduced dominance of nearby sectors, and interference-dominated connectivity. These effects result in fragmented association regions and increased variability in link performance. The analysis is supported by measurement data from a helikite-based spectrum monitoring campaign and corresponding simulation results. Despite differences in experimental conditions, both approaches exhibit consistent altitude-dependent trends. These findings provide practical insights for designing altitude-aware and interference-aware cellular systems to support reliable UAV operation.

翻译：无人机正日益融入蜂窝网络，以支持新兴的物联网应用。在此类场景中，可靠的通信对于实现共享空域内无人机的检测与跟踪至关重要，即电子显性。然而，无人机运行在高海拔时，增强的视距可见性会导致同时暴露于多个基站，从而产生强烈的蜂窝间干扰。本文从系统层面分析了无人机高度如何影响无线电环境及其对电子显性可靠性的作用。通过使用服务距离、关联行为及聚合接收功率等空间与网络级指标，我们表明高度增加会引发更强的多蜂窝交互、削弱邻近扇区的主导地位，并导致连接以干扰为主。这些效应使得关联区域碎片化，链路性能变差。该分析得到了基于高空气球频谱监测活动的测量数据及相应仿真结果的支持。尽管实验条件存在差异，两种方法均表现出一致的高度依赖趋势。这些发现为设计适应高度与干扰感知的蜂窝系统以支撑无人机可靠运行提供了实用见解。