Eigen-structure based near-field wideband sources localization

Energy sources localization problem has been extensively elaborated in far-field scenario, but yet been fully addressed in near-field scenario. This paper presents an eigen-structure based near-field wideband sources localization method using arbitrarily spaced sensor array. First, we introduce a near-field sensor signal model, which takes into account both the attenuation of the sound pressure and the time delay of the signal. Far-field scenario could be considered as a special case of it. Estimation of the source locations is based on the straightforward exploitation of the eigenstructure of array power spectral density matrices. We use the analysis proposed by Wax et al. that locations are chosen as those whose location steering vectors are most nearly orthogonal to the set of eigenvectors belong to noise subspace over each frequency bin, but with a slightly different formation. Far-field sources localization could be considered as a 1-D (azimuth only) or 2-D (azimuth and elevation) problem. Our method solves the 3-D (azimuth, elevation and range) localization problem. A fast algorithm but with a sacrifice in the freedom in sensor arrangement is also presented. Simulation tests prove its validity and good performance.