The objective of the proposed research is to make fundamental contributions to wireless indoor localization through innovations in algorithm and system design, and through ground-breaking applications. The wireless signal carries crucial information about its propagation paths, including the distance, angle and surroundings between communicating devices, which are primitives for finding location. Despite tremendous academic and industry efforts, indoor localization still hasn’t seen the ubiquitous availability and disruptive power anticipated. The proposed research aims to re-imagine the possibilities of indoor localization by focusing on (1) the protocol and algorithm design of new localization methods, (2) robust system design with considerations of scalability, privacy, security, cost, and deployment, and (3) the applications that a pervasive use of UWB may enable, including location-based connectivity, security and privacy.