Hybrid Data Fusion techniques for localization in UWB networks

In this paper, we exploit the concept of data fusion in UWB (ultra wide band) localization systems by using different location-dependent observables. We combine ToA (time of arrival) and RSS (received signal strength) in order to get accurate positioning algorithms.We assume that RSS observables are usually available and we study the effect of adding ToA observables on the positioning accuracy. The proposed architecture of hybrid data fusion (HDF) is based on two stages: Ranging using RSS and ToA; and estimation of position by the fusion of estimated ranges. In the first stage, we propose a new estimator of ranges from RSS observables assuming a path loss model. In the second stage, a new ML estimator is developed to merge different ranges with different variances. In order to evaluate these algorithms, simulations are carried out in a generic indoor environment and Cramer Rao lower bounds (CRLB) are investigated. Those algorithms show enhanced positioning results at reasonable noise levels.