Sensitivity of matched-field processing to sound-speed profile mismatch for vertical arrays in a deep water Pacific environment

Abstract

In this paper, the sensitivity of matched-field processing (MFP) to sound-speed profile mismatch (based upon archival profiles resulting in various degrees of mismatch) will be examined with emphasis on sources within 50 km. A 10-Hz source will be considered whose field is generated by a normal mode model where only the water-borne energy is used, thereby eliminating issues relating to the estimation of bottom parameters. Array parameters, i.e., number of phones and array depth, will be examined for their effects on range and depth localization for various degrees of mismatch. In particular, it will be indicated where an array is most and least sensitive to sound-speed mismatch as a function of depth from the surface and range from the source. Also, the issue of selecting the range increment for the minimum variance (Capon) processor will be briefly addressed and it will be pointed out how too crude an increment can lead to erroneous results. Finally, an example will be presented of coherent broadband (BB) MFP illustrating improved robustness and sidelobe suppression relative to both single frequency and incoherent BB results.