Low Cost and Precise Localization in a Remote-Powered Wireless Sensor and Identification System

A low cost and precise localization system based on a remote-powered UWB-RFID tag is presented for wireless identification, sensing, positioning and tracking. Our contribution is to utilize the Impulse Radio Ultra wideband (IR-UWB) communication in a RFID system. Such as conventional RFIDs, a tag captures energy from the received RF signal transmitted by a reader which also carries data and clock. However, instead of backscattering, an Impulse-UWB transmitter is used. By a low power design operation distance of 13.9 meters is achieved. A network consist of several readers provide power and retrieve data from the tags in a wide area. Due to the fine time resolution of the ultra-short pulse in IR-UWB, the UWB receiver in the readers are able to accurately approximate the time of arrival of the signal and based on the time-difference-of-arrival algorithm the position of the tag can be estimated precisely. In the line-of-sight scenario by a two-step acquisition system, ±16.8cm accuracy can be achieved. By a new communication protocol proposed based on slotted-ALOHA anti-collision algorithm, 2000 tags per second can be read. The tag circuitry is designed and implemented in CMOS 180nm technology in a single chip solution.