PEC: Synthetic Aperture RFID Localization with Aperture Position Error Compensation

In recent years, location-based services have been widely applied not only in daily life but also in automation industries. As one of main location sensing technologies, RFID based localization has attracted increasing attention. Existing synthetic aperture RFID localization systems use the inverse correlation filter to reconstruct holograms and achieve satisfactory accuracy. However, these methods require accurate aperture positions for theoretical signal construction, while the ubiquitous aperture uncertainty in practice causes non-negligible performance degradation. In this paper, we present PEC, an accurate synthetic aperture RFID localization system with aperture position error compensation, which has a major advantage over the classic systems for no need to know the exact trajectory of the synthetic aperture. We first build a mathematical model for localization and merge all coherent received signals to estimate the tag position. Then we propose an iterative algorithm which can alternately estimate both the tag position and the aperture position error. We have implemented and evaluated PEC using commercial-off-the-shelf (COTS) RFID devices. Extensive experimental results show that it achieves the cm-level accuracy with aperture position error in noisy environments, which proves its effectiveness and robustness.