Angle of Arrival Measurements with Ultra-wide Band Transceivers: Design and Evaluation

Ultra-wide Band (UWB) positioning systems estimate the user's position from several time-based measurements. While usually achieving decimeter-level accuracy, enhancing the measurements by additional measurements, such as Angle of Arrival (AoA), should improve the positioning performance and robustness. In this work, the design of our custom UWB-AoA board capable of time-based and angle-based measurements is presented. The board contained two DW1000 UWB transceiver chips with a common clock source and with independent communication interfaces, enabling parallel control of the chips. The AoA measurements using Time Difference of Arrival (TDoA) and Phase Difference of Arrival (PDoA) methods are discussed. The AoA estimation accuracy using TDoA and PDoA is evaluated experimentally with turntable experiments, done for several antenna configurations. The results show that with PDoA measurements it is possible to achieve AoA errors with 6.1 degrees standard deviation and +0.73 degrees mean for half-wavelength antenna separation and even better for longer antenna separations.