发表机构
Skylo Technologies（Skylo Technologies）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出开源GNU Radio测试平台gr-ntnisac，用于测试面向NTN-ISAC的5G LEO卫星无源接收器，通过仿真与硬件实验验证了直接路径对消等关键技术的性能。
AI 中文摘要
无源接收器可通过5G下行链路的回波感知附近物体。当发射机为低地球轨道（LEO）卫星时，单个发射机可覆盖广阔区域，但接收器需处理数十kHz的多普勒频移，且直接路径延迟会在每个观测间隔内变化。此类接收器在实际应用于卫星前，需在已知正确结果的环境中进行测试。本文提出gr-ntnisac，一款开源GNU Radio测试平台，该平台将仿真的LEO信道应用于标准5G新空口下行链路，通过两个有线通用软件无线电外设（USRP）传输，并针对每条路径的延迟和多普勒指令对接收器进行评分。同一接收器代码可在仿真、录制的捕获数据及硬件上运行。作为首次应用，我们测量了直接路径的对消效果，直接路径是会掩盖弱回波的强卫星信号。硬件上的对消深度为34.8 dB，无无线电的匹配仿真中为37.6 dB，说明无线电并非主要限制因素。受控仿真显示，仿真器的8抽头分数延迟滤波器以及几乎处于直接路径延迟处的仿真旋转叶片，各自将对消深度限制在约40 dB；若两者均不存在，对消深度可达71.0 dB。一款同时移除子载波响应和符号相位的诊断对消器，在相同捕获数据上达到72.7 dB。在一次传导捕获中，有效载荷辅助接收器在76.9%的驻留时间内检测到-25 dB的移动路径。
英文摘要
A passive receiver can sense nearby objects from the echoes of a 5G downlink. When the transmitter is a low-Earth-orbit (LEO) satellite, one transmitter covers a wide area, but the receiver must handle tens of kHz of Doppler and a direct-path delay that changes within every observation interval. Such a receiver should be tested where the correct answer is known before it is tried on a satellite. This paper presents gr-ntnisac, an open GNU Radio testbed that applies an emulated LEO channel to a standard 5G New Radio downlink, sends it through two cabled USRPs, and scores the receiver against the delay and Doppler commanded for every path. The same receiver code runs in simulation, on recorded captures, and on hardware. As a first use, we measure cancellation of the direct path, the strong satellite signal that masks weak echoes. Depth is 34.8 dB on hardware and 37.6 dB in a matched simulation without radios, so the radios are not the main limit. Controlled simulation shows that the emulator's 8-tap fractional-delay filter and a simulated rotating blade at almost the direct path's delay each limit depth to about 40 dB; without either, depth reaches 71.0 dB. A diagnostic canceller that also removes the per-subcarrier response and per-symbol phase reaches 72.7 dB on the same captures. On a conducted capture, a payload-aided receiver detects a -25 dB moving path in 76.9 percent of dwells.
CommentsVol. 11 No. 1 (2026): Proceedings of the 16th GNU Radio Conference / Articles
