| Popis: |
In recent years, geoacoustic inversion methods based on matched‐field processing concepts have been devised for inferring the sub‐bottom properties of shallow‐water waveguides using measurements of acoustic signals received on hydrophone arrays. The development of these matched‐field inversion (MFI) procedures is driven by two goals: (1) to obtain an accurate geophysical description of the morphology of the sub‐bottom structure, and (2) to characterize the acoustic response of the sub‐bottom so that its effect on sound propagation can be predicted. Knowledge of (2) can improve the effective ranges for using sound in underwater communication and/or source localization applications. Of practical interest is the question: How crude can our estimates of the sub‐bottom structure be and still allow successful acoustic source localization using model‐based signal processing methods? In this paper, a hybrid simplex simulated annealing MFI code [M. R. Fallat and S. E. Dosso, J. Acoust. Soc. Am. 105, 3219–3230 (1999)] is combined with a high‐order parabolic equation (PE) model and applied to geoacoustic inversion in a shallow‐water waveguide whose sub‐bottom properties vary with range. In particular, we investigate simple sub‐bottom characterizations for some test cases considered recently at the Inversion Techniques Workshop held in Gulfport, MS. a)Presently on exchange from the Defence Science and Technology Organisation, Australia. |
