Empirical Analysis and Characterization of Indoor GPS Signal Fading and Multipath Conditions

Moving GNSS towards indoor positioning is an important challenge. Increases in receiver sensitivity, the forthcoming increase in number of GNSS satellites and signal design improvements all contribute to addressing this challenge. Another remaining issue for GNSS-based indoor positioning is the impact of signal multipath phenomena in indoor environments. We designed an measurement campaign with the main object to assess the current state of GNSS as a positioning technology for indoor environments. In this paper we present the methodology for gathering and analyzing measurement campaign data and present first results, assessing GPS positioning performance parameters such as availability and accuracy and reasoning about environment-inherent performance limiting factors such a signal fading and multipath phenomena. The basis for this performance assessment is data gathered in a real-world indoor environment using state-of-the-art commercial receiver technology.