Long-Range mmID Localization and Orientation Sensing via Frequency-Divided Beam Multiplexing

Localizing objects and determining their accurate position and orientation at considerable distances within densely cluttered environments poses a formidable challenge. In this paper, the authors introduce a new approach utilizing ultra-low-power frequency-divided backscatter beams on a single tag to enable azimuth estimation. The reported mm-wave system leverages a cross-polarizing Rotman lens and radar system for its implementation. The details of the system-from the tags baseband and mm-wave front end to the properties of the radar-are presented and its multi-spectral and random-forest data processing methods are described, before the results of its testing in high clutter environments are presented and discussed. These findings underscore the tag's ability to achieve precise localization over more than 10m of range with a median error of 6.4 em, while also accurately determining orientation with a mean absolute error of
$3.6^{\circ}$
. This work not only addresses the pressing challenge of object localization and orientation detection but also lays a foundation for future advancements in extended-range sensing technology.