Path Persistency for High Precision Ranging in Different Building Architectures

Indoor positioning systems employing high bandwidth (up to ultra-wideband) time-of-arrival methods have attracted a lot of attention recently owing to their potential for precise localization and tracking of personnel or assets inside buildings where the GPS systems fail to operate. However, these systems suffer heavily due to severe multipath in indoor areas, leading to large positioning errors since direct path cannot be detected due to obstructions. This in turn leads to a condition that we call undetected-direct-path condition. An effective solution would be to exploit other multipath components to aid in the localization by analyzing their persistency in indoor areas. Tracking the mobile station in the absence of direct path is dependent on the internal structure of the building. We present how this method can be applied in different buildings to aid in the time- of-arrival based ultra-wideband localization and we propose a methodology to analyze the effect of different parameters of a building on the statistical behavior of persistency.