UWB Channel Measurements for Accurate Indoor Localization

Recently, indoor localization has attracted considerable attention. More importantly, indoor channel measurements and models are very essential to accurate characterization of the ranging error for military applications. This paper provides the results of UWB measurements and modeling performed for indoor geolocation applications. The measurement campaign took place in the Worcester, MA in a modern office building, a manufacturing floor, a residential house, and an old office building. A total of 2934 wideband measurements at frequency band of 3-8 GHz were collected in the four sites. Measurements were divided into indoor-to-indoor, outdoor-to-indoor, and roof-to-indoor conditions with two different polarity of the mobile antenna representing an upright soldier and a soldier lying on the ground. The models developed from the measurements represent a number of propagation scenarios for different areas in each set of measurements. In this paper we provide novel path-loss models of the first-detected path (FDP) and the total power which is essential for localization applications. In addition ranging error models are also provided which characterizes the behavior of the direct-path (DP) and its relationship to the error. All the models are presented for two different bandwidths of 500 MHz and 3 GHz.