Ultra Low-Power UWB-RFID System for Precise Location-Aware Applications

Ultra low-power radio-frequency identification (RFID) tag with precision localization is often the enabling technology for location-aware sensor applications. Impulse-Radio Ultra-Wideband (IR-UWB) is a promising technology to fulfill the usage requirements in indoor cluttered environment. An ultra low-power precise UWB-RFID localization system is proposed in this paper. The RFID tag is a transmitter comprising of a micro-controller board and a UWB impulse radio board. Power saving and precision localization is achieved by optimization of the circuit design for ultra short pulses as well as system architecture and operation. When 1 s sleep mode is incorporated with 0.72 ms active mode, the tag consumes on average 6.8 mu A when pulsing at 3.3 MHz rate with 15.5 dBm peak transmit power. The transmitted pulse is captured by low-cost energy-detection receivers at the locator. Measurement in a 6mx6m typical indoor environment demonstrates that the proposed system is able to achieve positioning accuracy of 10 cm. Due to the high sensitivity of the receiver (-71 dBm), the proposed system can reach a potential reading range of over 100 meters. The ultra low-power consumption, accurate ranging and positioning result, and long reading distance makes the proposed system suitable for a variety of intelligent sensor applications.