Space-time signal subspace estimation for wide-band acoustic arrays

Acoustic array applications are generally characterized by very large signal bandwidth. Most existing wide-band direction of arrival (DOA) estimators are based on binning in the frequency domain, so that within each bin the signal model is considered approximately narrow-band. In this work the basic inconsistency of the commonly used binning is first shown. It is shown that the recent Space Time MUSIC (ST-MUSIC) method, which estimates a set of narrow-band signal subspaces directly from the space-time array covariance and combines them within a Weighted Subspace Fitting paradigm, can restore wide-band DOA estimation consistency in most scenarios, obtaining a large variance improvement at high signal to noise ratio (SNR). In addition, a refined ST-MUSIC subspace weighting is proposed to improve accuracy, especially at low SNR.