Localization of multiple sources with moving arrays

An asymptotically efficient estimator based on the generalized least squares (GLS) criterion is proposed for the problem of localizing multiple narrowband stationary signals using an arbitrary time-varying array. The estimator approximates the maximum likelihood estimator for the large-sample case and when the signals are a priori known to be uncorrelated, exploits this to get better performance. A second estimator, the spatial-smoothing estimator, is found to be inferior in performance to the GLS estimator.