SuperSight: Sub-cm NLOS Localization for mmWave Backscatter

Abstract

Precise localization encompassing diverse indoor spaces is the key to immersive interaction services. In practice, indoor localization often undergoes blind spots as RF is easily blocked by everyday objects ranging from concrete walls, metallic shelves, and partitions to electronics and appliances. This paper presents SuperSight, an NLOS localization for mmWave backscatter that, for the first time, achieves NLOS (non-penetrable) localization without multipath environment profiling/manipulation. The key insight of SuperSight is uniquely exploiting the mmWave features of highly directional and specularly reflected multipath in combination with the triangular tag array to yield sub-cm NLOS localization accuracy over 8 m range - an order of magnitude performance enhancement compared to the competitors. Circularly polarized, 77GHz retro-reflective tag ensures high precision and robustness across diverse reflectors and tag orientations. The prototype was evaluated across six different reflector materials (including metal, concrete, and plaster) and demonstrated in the corridor and office space to reveal x, y, z position accuracy of up to (metal reflector) 5.7 mm, 5.5 mm, 7.7 mm at 8 m range, with Yaw, Pitch, Roll accuracy of 0.22, 0.28, 0.1 degrees respectively.