Development, performance analysis, and experimental evaluation of beamspace Root-MUSIC

A computationally efficient beamspace implementation of Root-MUSIC is developed. The algorithm exploits the common out-of-band nulls property exhibited by discrete Fourier transform (DFT) beams. For each set of B successive DFT beams encompassing a given spatial sub-band, the major computations are an eigenvalue decomposition of the real part of the B×B beamspace sample correlation matrix and the rooting of a polynomial of order 2B-2. Virtual tapering is effected by summing weighted DFT beams to yield reduced out-of-band sidelobes while retaining the common out-of-band nulls property. Experimental results are presented involving data obtained from an N=32 element uniformly-spaced, linear array operating at X-band