Synthetic Elements for Moving Line Arrays

Uniformly spaced line arrays (ULAs) exhibit spatial ambiguities governed by to the Nyquist sampling theorem. This results in grating-lobes which degrade array gain and also results in direction of arrival estimation ambiguities for signals of interest. The challenge associated with the formation of synthetic elements for line arrays (SELA) to eliminate grating lobes and perform failed channel recovery for ULAs is discussed. Objectives of the solicitation and the Phase I Basic and Option work are given. These objectives are to develop methodologies and SELA algorithms for exploiting towed array motion to process higher frequency regions at all steered directions in order to use the full frequency capability of a ULA; and to develop methods to mitigate the effects of missing array elements to improve beamformer performance in a degraded submarine (or other) towed array. A schedule and work plan is presented that is focused around the development and evaluation of algorithms addressing these two objectives. A Phase I Option work plan is submitted in which we propose developing a framework for real-time SELA algorithm implementation, performing an analysis of alternatives that includes estimate processor timing and sizing estimates for the proposed algorithms.