Design and Implementation of High-Precision UWB Indoor Positioning System with Numerous Users

Abstract

In the past few years, ultra-wideband (UWB) as a new type of wireless communication technologies has drawn an increasing attention in the field of indoor positioning. Since the UWB has ultra-high temporal resolution, the time of arrival (TOA) and time difference of arrival (TDOA) based ranging methods have found wide applications in UWB positioning systems. However, the existing positioning methods suffer from performance graduation due to the problem of high-resolution clock synchronization and limited number of located users. In this paper, a pseudo clock synchronization scheme based on the signal communication mechanism is proposed to resolve the clock synchronization problem. Through two-way communication between base stations, the proposed scheme achieves accurate clock synchronization while it is easy to implement in practical applications. In addition, under the framework of the signal communication mechanism, the mobile tags only receive the ranging signal from the base stations passively. Thus, the proposed scheme achieves the ability of unlimited number of located users theoretically. To further improve the positioning accuracy, the least square method is exploited to compensate the difference of the time resolution. The superior performance of the proposed positioning scheme has been verified by indoor positioning experiment on a prototype UWB positioning platform.