Indoor positioning from vibration localization in smart buildings

Indoor localization by means of a global navigation satellite system (GNSS) remains a difficult problem due to GNSS signal impairments created by the building's structure. This problem prompted the research community to devise many alternative techniques. Unfortunately, in order to locate persons indoors, these alternatives often require each person to carry some device to facilitate the localization process. This paper investigates the naturally-generated vibration signals from a person's footsteps as a potential source of information for indoor localization. Instrumenting a building with vibration sensors is a mature technology, but, historically, the role of the technology was measuring a building's response to external events (e.g., earthquakes), not for measuring occupant-generated vibrations. Some prior work studied outdoor detection of footsteps near borders or within restricted areas, but that environment and the localization objectives differed sufficiently from the scope of this research to limit the relevance of prior results. This paper reports on measurements from an instrumented, public building and examines viability of conventional localization algorithms for locating persons moving within a building. Noting the sub-optimum performance of these algorithms in this localization task, this paper proposes an extension to existing techniques to accommodate signal distortions encountered by vibrations in building structures.