Single-Anchor Ultra-Wideband Localization System Using Wrapped PDoA

The ultra-wideband (UWB) technology has been widely used in high-accuracy localization systems benefiting from its superior time-resolution and stability. In recent years, the single-anchor localization (SAL) scheme has attracted intense interests with its high accuracy, low system complexity, and low deployment costs compared to traditional UWB localization schemes. In this paper, we develop a SAL system which achieves 3D high-accuracy localization using time and wrapped phase measurements of UWB signals. We expand the array aperture to improve the localization accuracy and address the phase wrapping problem using information fusion. Statistical characterization of ambiguous position estimates is encapsulated by soft positional information (SPI), which is approximated by Gaussian mixture model (GMM) to accelerate the filtering process. The parameters of GMM are estimated by an efficient parallel algorithm and two filtering methods are proposed to track the agent in different scenarios using approximate SPI. Finally, we implement the system on a low-cost platform and experimental results show that the proposed SAL system can achieve decimeter-level 3D localization accuracy in outdoor and indoor environments.