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Ref.: SiPLAB Report 02/01, FCT, University of Algarve,2001.
Abstract
The INTIFANTE'00 (INTIFANTE is a madeup acronym from INTImate and
inFANTE)
sea trial was carried out in the vicinity of Setubal, situated
approximately
50 km to the south of Lisbon, in Portugal, during the period from 9 to
29
October, 2000. The leading institutions were the Instituto
Hidrografico, that
carried out the oceanographic observations and managed the research
vessel
NRP D. Carlos I, CINTAL/UALG that provided the acoustic data
acquisition
system and the emitted source signal control and IST, that was in
charge of
the high frequency data communications testing. Other
collaborating/participating
institutions were the NATO SACLANT Undersea Research Centre with the
loan
of the acoustic sound source and respective power amplifier and the
Ente Nazionale
per l'Energia ed l'Ambiente (ENEA) that participated in the
hydrological survey.
This sea trial served a number of specific purposes under the leading
projects
INTIMATE and INFANTE, namely to acquire data for testing the
Time-Reversal
Mirror (TRM) for underwater communications at low-frequency (Event 1),
internal
tide acoustic tomography through a 25 hours observation of continous
transmissions
(Event 2), source localization and tracking over strong environmental
variability,
(Event 3) and over a mild range dependent environment (Event 4). The
data
sets acquired during Events 1 to 3 are described in this report while
Event
4 is described in a companion report. The experiment area was a
rectangular
box situated in the border of the continental platform with depths
varying
from 60 to 140 m and including a sharp submarine canyon (the Setubal
canyon)
with depths rapidly reaching over 500 m. As an overview of the
technical
aspects involved in the experiment, it can be referred that acoustic
signals
were transmitted with an acoustic projector from onboard NRP D. Carlos
I
and received on a moored 16 hydrophone-4m spacing Vertical Line Array
(VLA).
The acoustic aperture of the vertical array was located between
30
and 90 m in a 120 m water column. The acoustic signals received in the
VLA
were transmitted via an RF link to the research ship NRP D. Carlos I,
processed,
monitored and stored. Various signals were emitted by the sound
projector
ranging from linear frequency modulated (LFM) sweeps, to broadband MPSK
modulated
binary sequences .