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 uA 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 6m×6m 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.