Abstract

This paper evaluates Wi-Fi Fine Timing Measure ment (FTM) for 3D indoor positioning and compares it with Ultra-Wideband (UWB). We follow a two-phase experimental methodology. First, we quantify ranging precision in a 45 m corridor under Line-of-Sight (LoS), Non-Line-of-Sight (NLoS), and mixed conditions. Second, we assess 3D positioning accuracy in a laboratory using nonlinear multilateration with four anchors, under both LoS and strong NLoS conditions. The evaluation uses commercial off-the-shelf FTM devices (Google Nest Wi-Fi and Pixel 6 Pro) and a Qorvo MDEK1001 UWB development kit. Results show that Wi-Fi FTM provides meter-level 3D positioning with minimal infrastructure, while UWB achieves substantially higher ranging precision and lower 3D positioning error under LoS. Under strong NLoS, both technologies suffer from reduced range availability, preventing 3D estimation when fewer than four ranges are returned. These results clarify the accuracy versus deployability trade-offs when selecting FTM or UWB for practical 3D indoor positioning.