Smart and Mobile Systems (SMILE) Lab

Accurate localization of a large number of objects over a wide area is one of the keys to the pervasive interaction with the Internet of Things. Our technique, for the first time, offers over (i) hundred-scale simultaneous 3D localization at (ii) subcentimeter accuracy for over an (iii) hectometer distance. The performance practically applies to indoors and outdoors as well as under mobility. Our custom backscatter consumes only 8.4 microwatts of power – i.e., over 40 years of battery life on a single cell. The tag's Van Atta array design with retro-reflectivity in both elevation and azimuth planes offers 3D localization and effectively suppresses the multipath. Our system is compatible to the commodity FMCW radar with a lightweight signal processing. It uniquely leverages the interplay between the tag signal and clutter to boost the signal quality by six orders of magnitude, and leverages the signal spectral leakage for fine-grained positioning. A 24GHz retro-reflective custom backscatter. The PCB-fabricated tag requires only 16 PIN diodes, achieving low-cost and low-power consumption. Super-resolution is achieved by a lightweight signal processing, without any hardware modification. It is compatible with commodity radar (EVAL-TinyRad).