TT-MSUA: A New Method for Time-of-Flight Tomography Based on a Moving Single UWB Anchor

The positioning based on ultra-wideband (UWB) mostly requires the target to carry tags, which is called active positioning. This method requires a constant power supply for the tag and is not suitable for continuous positioning. Therefore, we propose a localization method called passive localization that achieves target position perception without wearing assistive devices. Tomography as one of the most promising passive positioning techniques has many advantages. However, traditional tomography methods require a large number of fixed-position transceivers to form dense links to ensure accuracy. In underground environments such as tunnels, personnel positioning requires as few transceivers as possible. To reduce the number of devices, we propose a positioning system based on the moving single anchor, which obtains the signal’s flight time through communication between the moving anchor and the fixed tag. Time-of-flight (TOF) tomography is by utilizing the influence of the target on the communication time of each link. To better eliminate the error of multitarget monitoring in dense links, an elliptical model based on the first Fresnel region radius is proposed. Simulation and experiments have shown that the single target positioning accuracy reaches 0.1 m in a positioning area of
$6\times6$
m, and the maximum positioning error for eight targets is 0.5 m. The positioning error of multitarget positioning is reduced by about 85% compared to the method of multi-anchor fixation. It proves that this method has good multitarget localization performance.