Rep 04/05 - SiPLAB
17/Nov/2005
UniversityIt is now well accepted in the underwater acoustic scientific community that below, say, 1
kHz acoustic propagation models are accurate enough to be able to predict the received
acoustic field up to the point of allowing precise and reliable source tracking in range and
depth with only limited environmental information. This results from a large number of
studies both theoretical and with real data, carried out in the last 20 years. With the
event of underwater communications and the necessity to increase the signal bandwidth for
allowing higher communication rates, the frequency band of interest was raised to above
10 kHz. In this frequency band the detailed knowledge of the environment - acoustic
signal interplay is reduced. The purpose of the MakaiEx sea trial is to acquire data in
a complete range of frequencies from 500 Hz up to 50 kHz, for a variety of applications
ranging from high-frequency tomography, coherent SISO and MIMO applications, vector
- sensor, active and passive sonar, etc...The MakaiEx sea trial, that took place off Kauai I.
from 15 September - 2 October, involved a large number of teams both from government
and international laboratories, universities and private companies, from various countries.
Each team focused on its specific set of objectives in relation with its equipment or
scientific interest. The team from the University of Algarve (UALg) focused on the data
acquired by their receiving Acoustic Oceanographic Buoy - version 2 (AOB2) during six
deployments in the period 15 - 27 September. This report describes the AOB2 data
set as well as all the related environmental and geometrical data relative to the AOB2
deployments. The material described herein represents a valuable data set for supporting
the research objectives of projects NUACE1, namely to fulfill NUACE’s task 3 and 4 and
RADAR2, namely its tasks 2 and 3 devoted to the developement and testing of a field of
sonobuoys.This report presents the testing of the most recent version of the Acoustic Oceanographic
Buoy (AOB) system and the results obtained during the Makai Ex sea trial. The MakaiEx
sea trial took place off the west coast of Kauai I., Hawaii, USA, in the period September
15 - 27, 2005.
The authors of this report would like to thank:
• all the personnel involved, including R/V Kilo Moana crew
• the scientist in charge Michael B. Porter
• the University of Hawaii for its support
• FCT (Portugal) for the funding provided under projects NUACE (POSI/CPS/47824/
2002) and RADAR (POCTI/CTA/47719/2002).
• ONR for the funding under ONR-IFO VSP grant # N00014-04-1-403
