Acoustic Maritime Rapid Environmental Assessment
during the MREA'04 sea trial
S.M. Jesus, sjesus@ualg.pt
C.Soares, csoares@ualg.pt
P. Felisberto, pfelis@ualg.pt
A. J. Silva, asilva@ualg.pt
L. Farinha, lfarinha@ualg.pt
C. Martins, celestino.m@sapo.pt
SiPLAB - FCT, University of Algarve
Campus de Gambelas,
PT-8005-139 Faro, Portugal
Comments: download file (pdf)
Ref.: SiPLAB Report 02/05, FCT, University of Algarve,2005.
Abstract
Environmental inversion of acoustic signals for bottom and water column
properties is being proposed in the literature as an interesting
concept for complementing direct hydrographic and oceanographic
measurements for Rapid Environmental Assessment (REA). The acoustic
contribution to REA can be cast as the result of the inversion of ocean
acoustic properties to be assimilated into ocean circulation models
specifically tailored and calibrated to the scale of the area under
observation. Traditional ocean tomography systems and methods for their
requirements of long and well populated receiving arrays and precise
knowledge of the source/receiver geometries are not well adapted to
operational Acoustic REA (AREA). The Acoustic Oceanographic Buoy (AOB)
was proposed as an innovative concept that responds to the operational
requirements of AREA. That concept includes the development of water
column and geo-acoustic inversion methods being able to retrieve
environmental true properties from signals received on a drifting
network of acoustic-oceanographic sensors - the AOBs. An AOB prototype
and a preliminary version of the inversion code, was tested at sea
during the Maritime Rapid Environmental Assessment 2003 (MREA'03) sea
trial and was reported in Jesus [2003]. On a separate register it
should be noted that the characterization of the environment between
the source and the receiver also contributes to the identification of
the acoustic channel response and therefore provides a basis for
fulfilling the objectives of project NUACE (Non-cooperative
Underwater Acoustic Channel Estimation, FCT contract
POSI/CPS/47824/2002, initiated in January 2004). The present report
describes the data sets and results gathered during the MREA'04 sea
trial that took place from 29 March to 19 April 2004 off the west coast
of Portugal, south of Lisboa (Portugal), with the objectives of testing
an improved version of the individual AOB and its functionality in a
simple network. The acoustic part of the experiment lasted for four
days between April 7 and April 10, 2004 and involved the transmission
and reception of pre-coded signals along range-dependent and
range-independent acoustic tracks.
ACKNOWLEDGMENT: this work was partially supported by project NUACE (POSI/CPS/47824/2002) from FCT, Portugal.