Focussing matrices for coherent signal-subspace processing

A class of focussing matrices is proposed for use in the coherent signal-subspace method (CSM) (H. Wang and M. Kaveh, ibid., vol.ASSP-33, Aug. 1985). When the directions-of-arrival of wideband sources fall into more than one group of one beamwidth each, this class leads to performance substantially better than those suggested in previous studies on direction-of-arrival estimation. New insight into the structures of various focussing matrices and their effect on the performance of CSM is presented. The performance of CSM is compared for several classes of these matrices on the simulations as well as relative sufficiency analyses