Indoor footstep localization from structural dynamics instrumentation

Measurements from accelerometers originally deployed to measure a building's structural dynamics can serve a new role: locating individuals moving within a building. Specifically, this paper proposes measurements of footstep-generated vibrations as a novel source of information for localization. The complexity of wave propagation in a building (e.g., dispersion and reflection) limits the utility of existing algorithms designed to locate, for example, the source of sound in a room or radio waves in free space. This paper develops enhancements for arrival time determination and time difference of arrival localization in order to address the complexities posed by wave propagation within a building's structure. Experiments with actual measurements from an instrumented public building demonstrate the potential of locating footsteps to sub-meter accuracy. Furthermore, this paper explains how to forecast performance in other buildings with different sensor configurations. This localization capability holds the potential to assist public safety agencies in building evacuation and incidence response, to facilitate occupancy-based optimization of heating or cooling and to inform facility security. •A novel role for building structural dynamics instrumentation is locating building occupants by their footstep vibrations.•Conventional time difference of arrival algorithms for localization are inadequate in the complex propagation environment of a building's structure; new algorithms enable sub-meter localization accuracy.•Analysis of sensor geometric dilution of precision (GDOP) provides a quantitative means to evaluate constraints on localization performance created by a particular sensor layout.