Achievable performance of a novel Bragg-scattered acoustic receiving array

Abstract

The merits of a novel beamforming technique, based on generating Bragg-scattered acoustic wavelengths along the surface of an array, will be described. The technique, denoted acoustic trace wavelength enhancement, relies on embedding periodic structures within an array, chosen to precisely replicate and shift an incident acoustic wavenumber into higher wavenumber regions. Thus, shorter trace wavelengths are created over the aperture surface. The enhancement technique is documented in two recent publications: enhanced directivity with array grating [J. Acoust. Soc. Am. 136, 2014] and experimental verification of acoustic trace wavelength enhancement [J. Acoust. Soc. Am. 138, 2015). These references dealt, however, solely with high signal-to-noise ratios. Specifically, we will investigate the noise characteristics of this new array by calculating its array gain and Cramer-Rao lower bounds on bearing estimation error for plane wave signals embedded in an isotropic Gaussian noise field. Of particular interest...