A Low-Cost Ultra-Wideband Indoor Ranging Technique

This paper presents the development of a low-cost indoor ranging technique based on time-of-arrival (TOA) estimation, using short-pulse ultra-wideband (UWB) signals. The realized system includes two identical UWB transceiver devices, in which the receiver section is based on a tunnel diode detector and the pulse generation is performed by a common bipolar transistor driven in avalanche mode. An indirect measurement of the distance between the devices is obtained by measuring the frequency of the generated pulse train. A theoretical model of the system is described and a statistical analysis is presented, including the evaluation of the Cramer-Rao lower bound (CRLB) on the distance estimation. Furthermore the principle of operation of the realized system prototypes is described, along with some implementation issues. Finally experimental results are shown and discussed.