RFID-based indoors localization of tag-less objects

Object localization has become a necessary module in many radiofrequency identification (RFID) systems that require tracking features besides the conventional identification feature. A number of techniques exists in literature that uses the RFID signal information to locate the tagged objects, i.e. objects wearing RFID tags. Nevertheless, in many applications, it is required to track objects that do not carry a tag (whether intentionally or unintentionally). In this work, we propose a technique for tag-less object localization. The technique is based on reconstructing the attenuation map of the environment using back projection of RFID signals emitted from reference tags fixed on the walls of the monitored space. Numerical simulation as well as real-world data show the feasibility of the proposed method.