Closed-form DOA estimation with multiscale unitary ESPRIT algorithm

Signal processing aspects of smart (adaptive) antenna systems are concentrated on the development of emcient algorithms for direction of arrival (DOA) estimation and adaptive beamforming. This paper describes a multiscale Unitary ESPRIT, which is an extension of modified Unitary ESPRIT algorithm. The Unitary ESPRIT algorithm (with short baseline) is necessary to determine the sectors of source localization (or unambiguous coarse reference estimates). The modified Unitary ESPRIT algorithm (with baseline beyond a half wavelength) is preferred for accuracy. The multiscale Unitary ESPRIT permits to combine the estimates of Unitary ESPRIT and modified one to obtain the phase ambiguity free DOA estimate