Near-Field Localization for Mobile Robots With Single-Antenna Devices

Abstract

Utilizing device mobility to form virtual large-scale antenna arrays can provide accurate angle-of-arrival (AoA) information for robots. However, existing wireless localization systems that exploit device mobility are designed based on far-field channel assumptions and cannot directly provide range estimates. To address this problem, in this paper, we develop a novel near-field localization architecture for mobile robots by fusing the robot’s motion trajectory and channel state information (CSI) of a single antenna. Specifically, we first utilize channel reciprocity to multiply the uplink CSI and downlink CSI to eliminate the phase offset. Second, we further propose a two-stage localization algorithm that separates the line-of-sight (LoS) path from the multipath, and a multi-scale iterative scheme is employed to refine the estimation of AoA and distance of the LoS path. In addition, the range and AoA profiles for different trajectory shapes and the Cramer-Rao bounds for localization accuracy under squared channels are derived. Finally, the effectiveness of the proposed system is verified in a real environment. The simulation and experimental test results show that the proposed near-field localization system can operate in complex channel environments, and its localization accuracy outperforms the existing schemes.