Angle of arrival localization systems generally rely on multiple antenna arrays, estimating the position of a mobile node by measuring the line-of-sight directions. However, indoor multipath effects tend to deteriorate system performance. In this paper, an alternative system for in-room positioning is proposed and tested, consisting of a mobile transmitter and a single antenna array for angle of arrival estimation of direct and reflected signals. With the help of a floor plan of the room and a ray tracing algorithm, antenna array outputs can be calculated for every possible position of the mobile node. These simulation outputs are compared to the measurement results to determine the position of the transmitter. The system is evaluated in an extreme multipath environment, being a 2.25 m × 3 m room with metallic walls. Measurements are performed with a 2.45 GHz and a 5.2 GHz 8-element antenna array, followed by an MVDR beamforming algorithm with a variable number of spatial smoothing operations. Two distinct localization algorithms are tested, as well as the influence of various parameters on localization accuracy, resulting in an optimal setup with an average localization error under 1 m.
['Stijn Wielandt', 'Jean Pierre Goemaere', 'Lieven De Strycker']
Multipath-assisted angle of arrival indoor positioning system in the 2.4 GHz and 5 GHz band