A Handheld Fine-Grained RFID Localization System with Complex-Controlled Polarization

There is much interest in fine-grained RFID localization systems. Existing systems for accurate localization typically require infrastructure, either in the form of extensive reference tags or many antennas (e.g., antenna arrays) to localize RFID tags within their radio range. Yet, there remains a need for fine-grained RFID localization solutions that are in a compact, portable, mobile form, that can be held by users as they walk around areas to map them, such as in retail stores, warehouses, or manufacturing plants. We present the design, implementation, and evaluation of POLAR, a portable handheld system for fine-grained RFID localization. Our design introduces two key innovations that enable robust, accurate, and real-time localization of RFID tags. The first is complex-controlled polarization (CCP), a mechanism for localizing RFIDs at all orientations through software-controlled polarization of two linearly polarized antennas. The second is joint tag discovery and localization (JTDL), a method for simultaneously localizing and reading tags with zero-overhead regardless of tag orientation. Building on these two techniques, we develop an end-to-end handheld system that addresses a number of practical challenges in self-interference, efficient inventorying, and self-localization. Our evaluation demonstrates that POLAR achieves a median accuracy of a few centimeters in each of the x/y/z dimensions in practical indoor environments

The Possibility of Interference Suppression by Correlation Receiver Applied to Marker Localization

The actual applications of the radiofrequency identification (RFID) systems in industry are focused not only on the identification but also on the localization of the RFID transponders. The special type of the RFID transponders is used to localize and to identify the underground facility networks such as pipes and cables. In such applications the RFID transponders are called markers. The paper describes an analysis of the correlation receiver for RSSI based localization of the inductive coupled RFID markers. The analysis is performed by the modeling of the localization device and the marker in Matlab – Simulink software. The aim of the analysis is to examine the ability of the correlation receiver to suppress the interfering signals from industrial sources, for example from the long wave telemetry transmitters which have their working frequencies in the same band as the working frequencies of the markers