High frequency matched field processing

Abstract

Results are discussed from a high frequency (0 9-5 7 kHz), very shallow water (<10 m) experiment exploring the feasibility of carrying out matched field processing in this frequency and water depth regime The data was received on a 22- element vertrcal array witth interelement spacing one half-wavelength at 4 hz. An acoustic source broadcasting a multitone comb was towed along radial tracks wrth maxrmum range from the arraj of reveral hundred meters. One incoming track was selected for analysis using conventronal (nonadaptive) matched field processing. The structure of the range-depth ambiguity surface (incoherently averaged across frequency) 15 shown us well ar the time-evolving range surface (for a fixed source depth) In addrtron, trme serres of the range and depth maxima are shown along wrth thew corresponding correlatron values Although a very srmple range-dependent environmental model was used to generate the matched field replica vectors, the results clearly demonstrate the ability to track the motion of the source and resolve its position to on the order of 0.5 m m depth and 10 m in range.