RF-Track: Real-Time Tracking of RFID Tags with Stationary Antennas.

Passive wireless localization and track technologies have attracted much attention in academia recently. Although some schemes can locate tags with a centimeter accuracy, they usually require complex deployment or lack of real-time positioning capabilities, which is not practical in real-world applications. In this paper, we present a new localization method with the phase value in backscattered signal, called RF-Track, which aims for real-time tracking of passive RFID tags to high accuracy with 4 stationary antennas in real-time. We use simulation to analyze the proper layout of antennas and optimize the probability density function. Based on this, we implement RF-Track using COTS RFID devices. In addition, we applied some methods in real experiments, including reducing the impact of tag orientation, calibrating the antenna phase center, etc. to reduce the difference between actual and theoretical phase values to achieve similar results in simulation. The experimental results show that RF-Track can achieve an accuracy of 30mm and within 10mm after calibrating the track shifting.