E3DinSAR: 3-D Localization of RFID-Tagged Objects Based on Interference Synthetic Apertures

摘要

RFID is one of the indispensable technologies employed to implement the Internet of Things, where it facilitates the identification and awareness of objects in our daily lives by integrating backscatter tags. The interference synthetic aperture radar (InSAR)-based localization scheme provides high precision in 3-D conditions, although it still has some practical problems such as its strict sampling operation and it is also highly time consuming. In this article, we developed E3DinSAR as an optimized InSAR-based 3-D localization approach for pinpointing tags rapidly and easily with high accuracy. E3DinSAR does not use any other infrastructure or reference tags, and only one movable reader with one antenna is sufficient to implement the localization method, where it measures the phase value of the tag at different positions throughout its movement in order to create multiple holographic images. In contrast to the previously proposed InSAR-based technique, we extend the sampling trajectory of the reader to an arbitrary curve by restricting it to several approximate linear apertures, which allows more flexible operations and increase the accuracy. We also employ a rapid computing method to calculate the results for the holographic images by estimating the direction of arrival for the tag. Experiments were performed where E3DinSAR was implemented with commercial off-the-shelf (COTS) RFID products and our systematic evaluation showed that E3DinSAR achieved a mean locating accuracy of 18.4 cm in a 3-D space.