PERFORMANCE OF NARROWBAND SIGNAL-SUBSPACE PROCESSING.

The authors present an analytical evaluation of detection (determination of the number of sources) and estimation performance of narrowband signal-subspace processing for multiple-source direction-finding. The probabilities of underestimating and overestimating the number of sources are derived, under asymptotic conditions and around the threshold region, in terms of the choice of a penalty function and signal, noise, and array parameters for at most two closely spaced sources in spatially white noise. A scalar measure is introduced for evaluating the quality of the estimated signal-subspace. On the basis of the statistics of this measure performance, thresholds are demonstrated for the signal-to-noise ratio, angle separation, and correlation between two equipowered sources.