W-CBTI: A CIR Shift-Based W-Combination Model of Tomography Imaging Method Using a Moving Single Anchor in UWB Systems

Device-Free Localization (DFL) is a critical technology in the Internet of Things (IoT), applicable in target tracking and intrusion detection. To improve the accuracy of DFL systems while simplifying equipment deployment, this study introduces a novel mobile single-anchor positioning scenario, where an anchor is placed on a mobile vehicle to communicate with a tag in a fixed position. In the mobile anchor scenario, we propose a tomography imaging method based on the W-combined (W-CB) model, which was developed through the analysis of the shift patterns in Channel Impulse Response (CIR) induced by the presence or absence of a target in the DW1000 module. This approach effectively mitigates the adverse effects of multipath interference on signal accuracy. Experimental verification in a warehouse environment demonstrates that, when applied to tomography imaging, the CIR shift-based W-CB model maintains a positioning error within 0.20 m in 99 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula>, outperforming traditional ellipse weight models and methods that rely on the time of flight as an observation. Furthermore, it achieves higher accuracy when the distance between targets is minimal.