This work addresses the problem of localizing an impact in a dispersive medium (waveguide) using a network of vibration sensors (accelerometers), distributed at various locations in the waveguide, measuring (and detecting the arrival of) the impact-generated seismic wave. In particular, the last part of this document focuses on the problem of localizing footsteps using underfloor accelerometers.
The author believes the outcomes of this work pave the way for realizing real-time indoor occupant tracking using underfloor accelerometers; a system that is tamper-proof and non-intrusive compared to occupant tracking systems that rely on video image processing.
A dispersive waveguide (e.g., a floor) causes the impact-generated wave to distort with the traveled distance and renders conventional time of flight localization methods inaccurate. Therefore, this work focuses on laying the foundation of a new alternative approach to impact localization in dispersive waveguides. In this document, localization algorithms, including wave-signal detection and signal processing, are developed utilizing the fact that the generated wave's energy is attenuated with the traveled distance. The proposed localization algorithms were evaluated using simulations and experiments of hammer impacts, in addition to occupant tracking experiments. The experiments were carried out on an instrumented floor section inside a smart building.
As will be explained in this document, energy-based localization will turn out to be computationally cheap and more accurate than conventional time of flight techniques. / PHD / When a person walks, each footstep impact generates a tiny floor-quake. The floor-quake sends a shock wave traveling along the floor, and causes the floor to vibrate. If these vibrations are sensed/measured at different locations in the floor, then the measurements can be used to estimate the individual footstep impact locations. Estimating the location of each footstep impact can then be utilized to track the walking path of the person.
This dissertation proposes a novel footstep location estimation approach. The localization approach uses a group of underfloor vibration sensors, called accelerometers, to measure the footstep-generated floor vibration. Then, the sensor measurements are used to estimate footstep locations.
Footstep location estimates are generated using the fact that the strength/energy of the generated wave is absorbed by the floor, and consequently the wave energy is attenuated with the traveled distance.
The proposed footstep localization approach can be used to track occupants inside buildings, providing a tracking system that is non-intrusive compared to tracking occupants using a system of cameras and a video image-processing software.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/103466 |
| Date | 30 November 2017 |
| Creators | Alajlouni, Sa'ed Ahmad |
| Contributors | Electrical Engineering, Tarazaga, Pablo Alberto, Baumann, William T., Buehrer, Richard M., Embree, Mark P., Philen, Michael Keith |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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