Tracking moving sources using the rank-revealing QR factorization

The author investigates an updating scheme for the rank revealing QR (RRQR) algorithm described earlier by T.F. Chan (see Linear Algebr. Appl., vol.88, no 89, p.67-82 1987) and applies it to the direction of arrival problem. This technique allows for tracking of moving sources by taking advantage of the simplicity of the regular QR updating scheme and the rank-revealing property of the RRQR factorization. Subspace methods and the RRQR technique are reviewed. It is shown that the RRQR algorithm can be used to update signal and noise subspaces from the noise-free correlation matrix. Experimental results and comparisons with eigen-based signal and noise subspaces are presented