Classic acoustic tomography uses controlled sound sources to probe the ocean for its physical properties. Instead, passive ocean acoustic tomography aims at using natural noise sources, such as wind induced noise, wave noise, or shipping noise with the scope of inverting for the ocean and/or bottom geophysical properties. Most studies found in the literature make use of ambient noise and sea surface wind generated noise, to invert bottom parameters in shallow water regions. Recently, another approach used shipping noise as illuminating signals to invert for water column parameters [Jesus et al., Conference on Acoustic Variability, Lerici (Italy), September 2002]. In that work, a focalization process was used to simultaneous invert known geometrical and unknown environmental parameters. In particular it was shown that known geometrical parameters such as source range and depth, and receiving array geometry, could be used as focus and out of focus indicators. During the focus periods, estimated water column parameters favorably compared to independently measured values. One of the difficulties found with the shipping noise was the low received power and the difficulty to determine a sufficient number of stable frequencies. 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 an certain improvement where a stable localization and inversion could be seen throughout the run.
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