Uncrewed Aerial Vehicle (UAV) networks require accurate Air-to-Air (A2A) channel models, but most existing work focuses on Air-to-Ground links and leaves the sub-6 GHz A2A channel poorly characterized. We present preliminary 3.4 GHz A2A channel measurements collected with a lightweight, reconfigurable, open-source channel sounder built from USRP B210 software-defined radios and a high-precision GNSS-disciplined oscillator mounted on two UAVs. Measurements were conducted at the AERPAW Lake Wheeler testbed using a spherical flight trajectory around a second drone to capture channel behavior over varying altitudes, elevation angles, and relative headings. From these data, we analyze fundamental channel properties, extract channel impulse responses, model fading behavior as a function of link geometry, and characterize fading statistics including RMS delay spread. The resulting dataset and analysis provide a more realistic basis for the design, emulation, and evaluation of physical-layer and MAC protocols for next-generation UAV communication networks.

翻译：无人机网络需要精确的空对空信道模型，但现有研究大多聚焦于空对地链路，导致对sub-6 GHz频段空对空信道的认知仍不充分。本文采用基于USRP B210软件无线电和高精度GNSS驯服振荡器构建的轻量化、可重构开源信道探测仪，在两架无人机上搭载设备，收集了3.4 GHz频段空对空信道的初步测量数据。实验在AERPAW Lake Wheeler测试平台开展，通过围绕第二架无人机执行球形飞行轨迹，捕获不同高度、仰角和相对航向下的信道特性。基于这些数据，我们分析了基础信道特性，提取了信道冲激响应，建立了衰落行为与链路几何构型的关系模型，并表征了包括均方根时延扩展在内的衰落统计特征。所得数据集及分析为下一代无人机通信网络的物理层与介质访问控制协议设计、仿真与评估提供了更贴近实际的依据。