TWO-DIMENSIONAL SPATIAL-SPECTRUM ESTIMATION FOR WIDE-BAND SOURCES BASED ON INTERPOLATED CIRCULAR ARRAYS

In array signal processing, 2-D spatial-spectrum estimation is required to determine DOA of multiple signals. A circular array of sensors is found to possess several nice properties for DOA estimation of wide-band sources. C. Usha Padmini et al. (1994) have suggested that there is no frequency-direction ambiguity in azimuth estimation for wide-band signals by using a circular array, even without the use of any tap delay elements. In 2-D spatial-spectrum estimation for wide-band signals, we find that it is impossible to avoid the ambiguity in source frequency-elevation angle pairs using a circular array. In this paper, interpolated circular arrays are used to perform 2-D spatial-spectrum estimation for wide-band sources. In the estimation, a large aperture circular array (r min/2) is found to possess suprior resolution capability and robustness.