Ziv-Zakai bound on time-of-arrival estimation with statistical channel knowledge at the receiver

Time-of-arrival (TOA) based localization plays an important role due to the possibility to exploit the fine delay resolution property when wideband signals are adopted. This paper investigates lower bounds on TOA estimation error for wideband and ultrawide bandwidth (UWB) ranging systems operating in realistic multipath environments. In particular, analytical expressions for the Ziv-Zakai bound (ZZB) on TOA estimation error for multipath channels are provided and discussed under different operating conditions. Using these bounds it is shown how the a priori knowledge about the multipath characteristics can be accounted for in the TOA estimation performance. These bounds serve as useful performance benchmarks for the design of practical TOA estimators.