S.M. Jesus and C. Soares email@example.com and firstname.lastname@example.org
SiPLAB-FCT, Universidade do Algarve
Comments: download pdf file .
Ref.: Proc. Int. Conf. on Theoretical and Computational Acoustics, p.211-220, Honolulu, USA,2003.
Abstract : One of the most stringent impairments in the
and widespread of ocean tomography are the enormous equipment
to obtain a useful spatial coverage and resolution. In particular the
to have a perfect control both on the source and receiver sides over
areas and during long periods of time is seen as a major obstacle.
tomography has been proposed under various forms to take advantage of
sound sources to simplify the tomographic process while producing
inversion results for environmental parameters. Most of the results
in the literature make use of ambient noise, and sea surface wind
noise, to invert bottom parameters in shallow water regions. Recently,
approach used unknown deterministic signals and ship noise as
sources to invert for water column parameters [Jesus et al., ECUA,
(Poland), June 2002, and Conference on Acoustic Variability, Lerici
September 2002]. In that work, a focalization process was used to
invert known geometrical and unknown environmental parameters. In
it was shown that geometrical parameters such as source range and
and receiving array geometry, could be used as focus and out of focus
During the focus periods, estimated water column parameters favorably
to independently measured values. This was particularly true for the
deterministic signals, while for the ship noise the low received power
the difficulty to determine enough stable frequencies destroyed the
during several portions of the run.
In the present work, the received signal is used to deconvolve the source power, and thus obtain a full-spectrum weighting function for optimum frequency combination during the focalization process. Results obtained in the same ship noise data set have shown a significant improvement where a stable localization and inversion could be seen throughout the run.
ACKNOWLEDGMENT: this work was partially supported by LOCAPASS and ATOMS projects (FCT).