Reducing bias in beamspace methods for uniform circular array [DoA estimation applications]

In this paper, we characterize the error introduced by the beamspace transform when it is applied to a uniform circular array (UCA). Several algorithms for direction of arrival (DoA) estimation employ this modal transform. In particular, we focus on the UCA unitary root-MUSIC algorithm. The performance of such an estimator is degraded and bias occurs especially if the array has a small number of elements. Here we propose a novel technique for reducing the bias. This leads to practically bias-free DoA estimates.