Electrical Engineering and Computer Science

Defense Event

Improving RF Localization Through Measurement and Manipulation of the Channel Impulse Response

Benjamin Kempke

Friday, April 14, 2017
09:00am - 11:00am
3725 Beyster Bldg.

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About the Event

For over twenty years, global navigation satellite systems like GPS have provided an invaluable navigation, tracking, and time synchronization service that is used by people, wildlife, and machinery. Unfortunately, the coverage and accuracy of GPS is diminished or lost when brought indoors since GPS signals experience attenuation and distortion after passing through and reflecting off of building materials. This disparity in coverage coupled with growing demands for indoor positioning, navigation, and tracking has led to a plethora of research in localization technologies. To date, however, no single system has emerged as a clear solution to the indoor localization and navigation problem because the myriad of potential applications have widely varying performance requirements and design constraints that no system satisfies. Fortunately, recently-introduced commercial ultra-wideband RF hardware offers excellent ranging accuracy in difficult indoor settings, but these systems lack the robustness and simplicity needed for many indoor applications. We claim that an asymmetric design that separates transmit and receive functions can enable many of the envisioned applications not currently realizable with an integrated design. This separation of functionality allows for a flexible architecture which is more robust to the in-band interference and heavy multipath commonly found in indoor environments. In this dissertation, we explore the size, weight, accuracy, and power requirements imposed on tracked objects (tags) for three broadly representative applications and propose the design of fixed-location infrastructure (anchors) that accurately and robustly estimate a tag's location, while minimizing deployment complexity and adhering to a unified system architecture. Enabled applications range from 3D tracking of small, fast-moving micro-quadrotors to 2D personal navigation across indoor maps to tracking objects that remain stationary for long periods of time with near-zero energy cost. Each application requires careful measurement of the ultra-wideband channel impulse response, and an augmented narrowband receiver is proposed to perform these measurements. The key design principle is to offload implementation complexity to static infrastructure where an increase in cost and complexity can be more easily absorbed and amortized. Finally, with an eye towards the future, we explore how the increasingly crowded RF spectrum impacts current ultra-wideband system design, and propose an alternative architecture that enables improved coexistence of narrowband and ultra-wideband transmissions.

Additional Information

Sponsor(s): Prabal Dutta

Open to: Public