Space-time diversity for NLOS mitigation in TDOA-based positioning systems

This paper studies the potential impact of using space-time information in the mitigation of the Non-Line-Of-Sight condition in mobile subscriber's positioning systems. First of all, this work discusses the positioning problem based on measures of Time Differences Of Arrival departing from a more exact characterization of the signal statistics and including some geometrical restrictions to achieve an improved accurate. Furthermore, a novel approach that integrates signal propagation characteristics to information provided by a suitable timing estimation model based on Cramer Rao Bound for a Rayleigh-fading channel, when antenna arrays are used at the receiver and when a set of channel vector estimates are available, has been introduced to study the positive benefits of space-time diversity. These approaches are evaluated within a realistic simulation scenario.