ASA 127th Meeting M.I.T. 1994 June 6-10

3pUW2. Experimental spatiotemporal signal correlation functions in a shallow water environment (SWellEX-1).

L. A. Shook

Appl. Sci. Div., Code 572, NRaD, San Diego, CA 92152-5000

F. J. Ryan

NRaD, San Diego, CA 92152-5000

During 2 weeks in August 1993, a high-fidelity acoustic experiment, SWellEX-1, was conducted in shallow waters off San Diego, CA. The SWellEX-1 site is a 50-to 200-m bottom-limited shallow water environment characterized by thin sediments and strong range dependence. During the course of the experiment extensive synoptic oceanographic measurements were collected. The site's bathymetry and geoacoustic bottom properties are characterized on a 2-arcsecond lat/lon grid. Broadband and tonal signals (50--750 Hz) from calibrated projectors were received on a 48-channel, 90-m aperture vertical line array (VLA) spanning the lower half of the water column. Source tows were conducted along the isobath and up-slope relative to the VLA. Experimental results of signal propagation and spatiotemporal vertical correlation functions will be presented along with high-fidelity full-wave simulations. The impact of a strongly bottom-limited shallow water environment on signal correlation and the resulting effect on plane-wave signal processing schemes will be investigated. Relative signal phase stability results will be presented and its impact on inverse synthetic aperture processing discussed. [Work supported by ONR under NRaD block CS3A.]