DIRECTION-OF-ARRIVAL AND FREQUENCY ESTIMATIONS FOR NARROW-BAND SOURCES USING 2 SINGLE ROTATION INVARIANCE ALGORITHMS WITH THE MARKED SUBSPACE

In array signal processing, one is frequently interested in simultaneously estimating the directions of arrival and the centre frequencies of the uncorrelated narrowband radiating sources having different centre frequencies. By using single spatial rotation invariance and temporal rotation invariance algorithms, e.g. the original ESPRIT, we can individually estimate the spatial frequencies-alpha(i) and the temporal frequencies-omega(i) of the sources. If detecting radiating sources only in azimuths is of interest, the spatial frequency-alpha(i) is defined as alpha(i) = omega(i) sin (theta(i)), where theta(i) is the location of the ith source relative to the broadside of the array, and we need decide which of the omega(i) and alpha(i) values belong to the same radiating source to obtain the pair {theta(i), omega(i)} for each source. In this paper, we propose a technique, the marked subspace technique, which is applied to the original ESPRIT to obtain the parameter pair {theta(i), omega(i)}. By using both single spatial invariance and single temporal invariance algorithms along with the marked subspace, the parameter pair {theta(i), omega(i)} of each radiating source can be more easily obtained than using the original ESPRIT without the marked subspace.