Measurement and Analysis of UAV Air-to-Ground Radar Sensing Channel in Campus Scenarios

To enhance the sensing capabilities of unmanned aerial vehicles (UAVs) during low-altitude flight and ensure their safe and reliable operation across diverse environments, the investigation of UAV air-to-ground (A2G) radar sensing channels has become increasingly critical. This study establishes a UAV A2G radar sensing channel measurement platform based on a 77 GHz frequency-modulated continuous wave (FMCW) millimeter-wave radar. For varying UAV motion states, a systematic channel measurement campaign was conducted in complex campus environments, resulting in a comprehensive dataset. Focusing on UAV horizontal flight conditions, the study first extracts channel impulse responses (CIRs) from measured field data. Subsequently, the space alternating generalized expectation maximization (SAGE) algorithm is employed to estimate multipath components (MPCs) within the channel. Finally, large-scale and small-scale fading characteristics, including path loss (PL), root mean square (RMS) delay spread and Rician K-factor, are quantitatively analyzed based on the estimated MPCs. This work further develops an empirical statistical model for UAV A2G radar sensing channels in campus scenarios, providing foundational insights for channel characterization in similar environments.