Near-Field Localization in UAV-Mounted HRIS System

In this paper, we propose a near-field localization algorithm for an unmanned aerial vehicle (UAV)-mounted hybrid reconfigurable intelligent surface (HRIS) system. Since the position of HRIS is unknown, joint localization of HRIS and UE should be considered. To solve this problem, the HRIS is equipped with a single radio frequency (RF) chain receiver, enabling tunable reflection and sensing through power allocation. Then, both HRIS and UE receive signals and perform localization separately, which can decouple the angle of arrival (AoA) and angle of departure (AoD) in HRIS. For localization, the maximum-likelihood (ML) is adopted. Through the simulation results, we have verified the efficacy of the proposed algorithm by comparing the theoretical lower bound.