Direction-of-Arrival Estimation in the Presence of Correlated Signals with Non-Ideal Uniform Circular Arrays

The Davies transformation is a method to transform the steering vector of a uniform circular array (UCA) to a vector with Vandermonde form. As this form is similar to that of the steering vector of a uniform linear array (ULA), we can apply to UCAs the many tools that have been developed for ULAs. However, the Davies transformation can be highly sensitive to perturbations of the underlying ideal array model. In this paper, we present two different methods for deriving a more robust transformation. The main underlying idea is to trade off robustness against accuracy of the Vandermonde form. In particular, we consider its application to direction-ofarrival estimation in the presence of correlated signals using root Weighted Subspace Fitting (root-WSF). The effectiveness of these methods are illustrated through numerical examples.