Precise localization of mobile robots in GNSS-challenged urban mobility scenarios : experimental insights on the Influence of anchor vertical placement using ultra-wideband

Abstract

Autonomous navigation of mobile robots and micromobility vehicles in dense urban corridors requires decimeter-level localization accuracy that GNSS (Global Navigation Satellite System) alone cannot reliably provide. Ultra-wideband (UWB) offers a promising complementary solution via precise time-of-flight measurements. However, UWB outdoor localization remains underexplored, particularly how anchor geometry affects positioning performance. This paper presents experimental insights into the influence of anchor vertical placement on two-dimensional (2D) UWB positioning accuracy outdoors. Three anchor-height configurations were evaluated over a 7 m x 10 m field using a custom Qorvo DWM3000-based UWB beacon system built at HAW Hamburg: one homogeneous baseline configuration (all anchors at 2.7 m) and two configurations with incremental height variations up to 0.6 m. Static measurements were conducted with the tag mounted at 0.80 m to simulate a mobile robot. Positioning performance was assessed via mean position offsets, standard deviations, 2D positional scatter, and Dilution of Precision (DOP) analysis.