Analysis of RSSI based positioning with multiband OFDM UWB

Ultra-wideband (UWB) enables accurate Localization and Tracking (LT) applications. However, the required and sophisticated time of arrival (ToA) ranging procedure relies on accurate synchronization and time measurements. Today, only few UWB devices support the required ranging feature. Examples are pulse based low data rate (LDR) UWB devices. Conventional multiband OFDM based high data rate (HDR) UWB devices do not support the ToA ranging feature. But the ultra wide frequency bandwidth of UWB enables not only high resolution of space surrounding UWB transceivers and therefore accurate time measurements, its enormous frequency diversity also minimizes fading effects. This allows reliable distance measurements, based on measurements of the received signal strength (RSS). This paper shows, that RSS based localization can be as accurate as ToA based localization. For this purpose, measurement results of the RSS and a derived path-loss model are used to calibrate a Monte Carlo simulator for RSS based ranging and localization. The RSS measurements are done with conventional Certified Wireless USB (CWUSB) sticks, using HDR UWB. For a small 4 × 4 meters network, the simulation results show mean localization errors between 0.1 and 0.3 meters.