Fundamental Limits in the Accuracy of Wireless Positioning

Several factors impact in practice on the achievable accuracy of wireless positioning systems. However, theoretical bounds can be set to determine the best accuracy one may expect in certain conditions and to obtain useful benchmarks when assessing the performance of practical schemes. Chapter 4 is dedicated to the presentation of several such bounds, most derived from the Cramér-Rao bound (CRB) framework. Theoretical performance bounds related to the ranging estimation via time-of-arrival (TOA) from UWB signals are derived and discussed, also taking into account critical conditions such as the multipath propagation. Also the improved Ziv-Zakai bound family is introduced as a tighter benchmark in the case of dense scattering, where the CRB falls in the ambiguity region. Then, novel results are presented, related to the derivation of performance limits for innovative positioning approaches, such as direct position estimation (DPE) in GNSS, cooperative terrestrial localization, and a recent analysis on the interference-prone systems, such as multicarrier systems.