Synthetic Elements for Moving Line Arrays - MP 85-09

Towed arrays provide the potential for creating synthetic elements located at positions a fraction of the distance between the actual elements, thus sampling the spatial field at a higher rate and allowing for operation at higher frequencies without grating lobes. Synthetic elements may also be used to fill in for failed sensors. The ability of a towed array system to fully exploit the synthetic elements and achieve the performance of the equivalent fully populated array depends on the temporal and spatial coherence of the observed signals. In Phase I, we will develop a mathematical framework for analyzing the towed array passive synthetic aperture sonar system that takes into account the statistical properties of realistic broadband and narrowband source signals and noise, develop a set of adaptive beamforming and DOA estimation algorithms that can be applied to a variety of broadband and narrowband signal and noise models, and analyze the performance using a suitable set of performance metrics and bounds. The algorithms will be tested on simulated data and implementated in an architecture that is suitable for processing real data.