EFFICIENT ACOUSTIC FIELD COMPUTATION FOR ESTIMATING GEOACOUSTIC BOTTOM PARAMETERS USING MATCHED-FIELD INVERSION

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Authors
  1. Henson, N.G.
  2. Hannay, D.E.
  3. Scrimger, P.
Corporate Authors
Defence Research Establishment Pacific, Victoria BC (CAN);JASCO Research Ltd, Sidney BC (CAN)
Abstract
Matched-field inversion for source location, environmental properties, or a combination of the two (focalization) is based on comparing acoustic fields measured at an array of receivers to replica fields propagation model. Although this approach is conceptually straightforward and widely applicable, it requires a large number of replica-field computations and can be impractically slow if the propagation modelling is not carried out in an efficient manner. This is particularly true for environmental inversion and focalization problems where the expanded parameter search space generally requires a very large number of replica-field computations, even if an efficient optimization algorithm such as simulated annealing (SA) is employed. Therefore, to apply these methods to realistic problems, it is important that the propagation modelling be performed as efficiently as possible. This paper presents a method of inversion using SA optimization and rapid acoustic field modelling based on the use of pre-computed mode functions and wave numbers (generated from the KRAKEN normal mode program) and stored in 'look-up' tables. The method is described together with the results of a study which established the optimum size of the grid elements required to achieve accurate propagation modelling and reliable matched-field inversion using this 'look-up' table method. TRUNCATED.
Keywords
KRAKEN COMPUTER PROGRAM
Report Number
DREP-CR-94-54 — Contractor Report
Date of publication
01 Apr 1994
Number of Pages
65
DSTKIM No
95-00356
CANDIS No
146695
Format(s):
Hardcopy;Document Image stored on Optical Disk

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