NLOS mitigation for ultra wideband localization

Abstract

One of the interesting properties of ultra wideband (UWB) signal is its superior performance and high accuracy in localization applications. This is mainly due to its high resolution resulting from its small pulse duration that is in the order of nanoseconds. However, this accuracy is affected by several factors. The killer one among those factors is the non line of sight (NLOS) propagation. In this research, the work includes the installation and implementation of a real time localization system (RTLS) provided by Ubisense. The work involves the study of small-scale and large-scale effect on the system accuracy. In addition, obstructed and NLOS scenarios are considered. The work also suggests an improved Residual weighting (Rwgh) mitigation algorithm to minimize the effect of NLOS. The work considers a channel based on IEEE 802.15.4a UWB channel model. Both indoor and outdoor environments are considered in the simulation. The localization part of the work is based on a modified version of the approximate maximum likelihood time difference of arrival (AML-TDOA) algorithm where different noise variances are considered. The simulation part considers the investigation of different parameters on the accuracy of the mitigation algorithm.