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Tróia, 9 - 29 October 2000

PRAXIS XXI contracts
INFANTE - 3/3.1/TPAR/2042/95
INTIMATE - 2/2.1/MAR/1698/95 (ending)
ATOMS - PDCTM/P/MAR/15296/1999 (starting)

António Pascoal
ISR - Instituto Superior Tecnico, Lisboa, Portugal
Emanuel F. Coelho
Instituto Hidrográfico, Lisboa, Portugal
Sérgio M. Jesus
CINTAL - Universidade do Algarve, Faro, Portugal
Paola Picco,
ENEA - Italy

Brief description

The INTIFANTE'00 sea trial took place from 9 - 29 October, 2000 in the continental platform near Setúbal, west coast of Portugal. The research vessel involved was NRP DOM CARLOS I from the Portuguese Navy and run by the Instituto Hidrografico. INTIFANTE'00 was composed of three parts:

Environmental Survey from 16 to 29 October,
INFANTE'00 from 9 to 13 October,
INTIMATE'00 from 16 to 20 October.

Environmental Survey

During this part environmental data such as, CTD, geoacoustic, seismic, bathymetry and currents was gathered in the designated area to support the acoustic measurements to be performed under INFANTE and INTIMATE.

INFANTE'00 Sea Trial

Objectives: this part of the sea trial served for testing underwater acoustic communications systems and to test the navigation system of a remote controlled catamaran. It involved deploying transmission modules in the sea bottom and communication either to the surface and/or to an high-frequency array of receivers.
Scenario:the NRP Dom Carlos I deployed the bottom and surface modules for testing underwater communication algorithms and methods. She also deployed the catamaran (DELFIM) for autonomous navigation testing. During two days off-vertical transmissions were performed from bottom module to a surface suspended array of receivers transmitting received signals via radio back to NRP Dom Carlos I for monitoring, checking and backup.

INTIMATE'00 Sea Trial

Objectives: this sea trial followed previous experiments (see INTIMATE'96 ) and has the objective of determining internal tides by means of acoustic tomographic measurements. Additional objectives during this sea trial were to acquire data to support highly range-dependent source tracking and tomographic inversion with random signals (either computer generated or ship induced noise).
Scenario: NRP Dom Carlos I deployed a sound source and transmitted signals to a moored vertical array and listened to received signals via an RF link. The sound source performed a number of geometries around the receiving array. The sound source was loaned by courtesy of SACLANT Undersea Research Centre, La Spezia, Italy.

Cruise Report

Starting was delayed for 4 days due to adverse weather conditions. INFANTE has completed one event out of 3 due to equipment failure (lack of communication between bottom and surface modules). DELFIM catamaran deployment was accomplished during the third week. INTIMATE objectives have reached 100% completion with over 50 GBytes of data acquired. Environmental survey tasks have been only partially achieved due to the redraw of NRP Almeida Carvalho due to equipment failure. In order to achieve a sufficiently accurate oceanographic description of the area, NRP D. Carlos I performed extra oceanographic measurements with the collaboration of Paola Picco from ENEA. Seismic and sidescan sonar surveys were done during the third week with success.

Some pictures taken during the sea trial:

last update on April 20, 2001