“ Ultra - Wideband Ranging in Dense Multipath Environments

Ultra-wideband (UWB) radio, a new carrierless communication scheme using impulses, is a candidate technology for future communication and ranging applications. Recent progress on both in the technical and regulatory side of this technology has made this possible. The fine time resolution and material penetration capability of UWB signals has created a vision of novel ranging and positioning applications to augment existing narrowband systems operating in dense multipath environments. In this thesis, a time-of-arrival (ToA) based ranging scheme using an UWB radio link is proposed. This ranging scheme, based on maximum likelihood estimation, implements a search algorithm for the detection of the direct path signal in the presence of dense multipath. Models for critical parameters in the algorithm are based on statistical analysis of propagation data, and the algorithm is tested on another independent set of propagation measurements. The proposed UWB ranging system uses a correlator and a parallel sampler with a high speed measurement capability in each transceiver to accomplish two-way ranging between them in the absence of a common clock. The UWB ambiguity function illustrates the effects of time offset and scaling factor (or clock offset) on the receiver’s correlator output.