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Advisor(s)
Abstract(s)
A vector sensor is constituted by one omni directional
pressure sensor and three velocity-meters that are sensitive
in a specific direction - x, y or z. Since a vector sensor is able
to measure the three particle velocity directional components it
acts as a spatial filter and therefore is advantageous in three
dimensional direction of arrival (DOA) estimation. The potential
gain obtained in DOA estimation can be extended to other
geometric parameters such as source range and depth, as well
as seabed parameters. The objective of this paper is to present
experimental results of a four element vertical vector sensor
array (VSA) data set collected during MakaiEx'05 experiment for
geometric (range and depth) and seabed geoacoustic parameter
estimation (sediment compressional speed, density and compressional
attenuation). The parameter estimation problem is posed
as an inversion method based on an extension of the conventional
pressure only Bartlett estimator to particle velocity. The
developed VSA based Bartlett estimator is proportional to the
pressure only Bartlett estimator response by a directivity factor,
providing an improved side lobe reduction or even suppression
when compared with the pressure only response. This behavior
will be illustrated for geometric and seabed parameters clearly
showing the advantages of the use of VSA over hydrophone
arrays. In source localization the VSA outperforms an array
of hydrophones of same number of sensors. Moreover, when
the VSA Bartlett estimator is applied for seabed parameter
estimation, it will be shown that the estimation resolution of
these parameters increased significantly, even for density and
compressional attenuation, parameters difficult to estimate using
an array of hydrophones.
Description
Keywords
Vector sensor array processing Geoacoustic