Direction Finding with UWB and BLE: A Comparative Study

Using Angle-of-Arrival based on Phase-Difference-of-Arrival is a recent trend in indoor positioning. Although the basic techniques for direction estimation have been known and used for a long time in different application scenarios (e.g., RADAR), the complexity of Phase-Difference-of-Arrival transceivers discouraged its use for indoor applications. This scenario changed with the recent development of modern chips at competitive prices. Specifically, two ubiquitous technologies in the context of indoor positioning, namely Bluetooth Low Energy (BLE) and Ultra-Wideband (UWB), currently feature Angle-of-Arrival estimation. In this paper we compare these two technologies regarding their potential for indoor positioning based on a fair evaluation of their performance for estimating Angle-of-Arrival in five different realistic setups. The results obtained are compared with existing studies when available. Our results show that Ultra-Wideband is, in general, more accurate and precise, especially when subject to multipath interference. Additionally, we discuss possible approaches to improve the accuracy and precision of Angle-of-Arrival estimation using BLE, such as the impact of increasing the number of antenna elements. By using UWB, we achieved an angular accuracy of up to 5° even under obstructed LOS and multipath, while an overall mean error of nearly 25° was obtained with BLE in an outdoor scenario without obstacles.