Calibration of a 2.45 GHz indoor Direction of Arrival system based on unknown antenna gain

In this paper we discuss the calibration procedure and effectiveness for an indoor Direction of Arrival (DOA) positioning system based on a switched six-beams antenna operating at 2.45 GHz. The introduced calibration procedure consists in optimizing the radiation pattern parameters of the antenna to minimize DOA estimations error, over a limited set of known positions. The estimations are obtained by the multiple signal classification (MUSIC). We demonstrate that in a realistic indoor environment the mean errors for the DOA estimations are less than 4.9 deg for both the DOA coordinate angles θ and θ, with a peak error of 8 deg, while a DoA estimation accuracy less than 3 deg was observed.