Discrimination of near-field infrasound sources based on time-difference of arrival information

Abstract

A computationally efficient method for discriminating between near- and far-field infrasound sources using array time-difference of arrival (TDOA) information is described. Rather than assess wave-front curvature, the discriminant quantifies the statistical departure of TDOA information from that of a plane wave passing the array. Since the method constrains neither the functional form nor the amplitude characteristics of a signal it is suited for discrimination of signals across large-aperture infrasound arrays. Experimental results confirm theoretical predictions to a range of order ten array apertures. The discriminant is applied to data from an Antarctic infrasound array.