Indoor Localization with Passive RFID System Based on Phase Difference of Displacement

This is the author's accepted version of:
U. Kumbul, A. Farsaei, A. Sheikh, and G. Dolmans, "Indoor
Localization with Passive RFID System Based on Phase Difference
of Displacement," Proc. 19th European Conf. on Antennas and
Propagation (EuCAP), Glasgow, UK, Mar. 2025.
doi: 10.23919/EuCAP63536.2025.10999484
The final version is available at:
https://doi.org/10.23919/EuCAP63536.2025.10999484

Abstract-The radio frequency identification (RFID) system is
investigated for indoor localization. The phase difference between
the relative displacement of the tag is used to estimate the
range towards each anchor. The updated range information at
each anchor is then used to compute the coordinates of the
tag using analytical multilateration positioning. The localization
performance of this multilateration method is demonstrated
experimentally and compared with maximum likelihood positioning,
which serves as an upper bound for localization performance.
The experiments show that the passive RFID system with analytical
multilateration positioning can achieve localization errors
between 0.06 m and 0.18 m for the chosen trajectory.

Index Terms-RFID, Positioning, Phase-based Ranging, IoT,
Phase Difference of Arrival, Indoor Localization.