On the application of uniform linear array bearing estimation techniques to uniform circular arrays

The problem of estimating the directions of arrival of narrowband plane waves impinging on a uniform circular array with M identical sensors uniformly distributed around a circle is considered. Specifically, the authors study a transformed data sequence that is equal to a reordering of the inverse discrete Fourier transform sequence corresponding to the outputs of a circular array with M elements uniformly distributed around the array circumference. It is shown that the transformed sequence may be processed using a ROOT MUSIC based approach to estimate the elevations and azimuths of the observed sources. Any root estimated via ROOT MUSIC which is on or close to the unit circle indicates the presence of a source at the elevation under consideration and an azimuth equal to the phase of the root. Experimental results are provided to demonstrate the advantages of processing the transformed data