C. Soares csoares@ualg.pt
FCT - Universidade do Algarve,
Campus de Gambelas,
PT-8000 Faro, Portugal.
M. Siderius martin.siderius@saic.com
SAIC, Sand Diego
USA
S.M. Jesus sjesus@ualg.pt
FCT - Universidade do Algarve,
Campus de Gambelas,
PT-8000 Faro, Portugal.
Comments: download pdf file.
Ref.: J. Acoust. Soc. Am., Vol. 112 (5), pp. 1879-1889,
2002.
Abstract
The ADVENT'99 sea trial took place in the area of the Adventure Bank in the
Strait of Sicily during May 1999, with the objective of testing matched-field
processing (MFP) techniques. A 62 m aperture - 31 hydrophone vertical line
array was deployed at 2, 5 and 10 km from an acoustic source. The source was
emitting a series of multi-tone signals alternating with LFM sweeps in two
frequency bands: 200-700 Hz and 800-1600 Hz.
One of the most stringent impairments in MFP is the impact of missing or
erroneous environmental information on the final source location estimate.
This problem is known in the literature as model mismatch and is strongly
frequency dependent. A number of MFP processors have been proposed to cope
with inevitable model mismatch in real data. The approach taken in this paper
includes a incoherent broadband conventional Bartlett processor used in a
two step procedure: in the first step the data is pre-focused using genetic
search where the environmental and geometric parameters are estimated and
in the second step an exhaustive search is performed for source range and
depth.
This method showed to be effective up to 10 km range in both frequency bands
achieving a precise localization during the whole recording of the 5 km track,
and most of the 10 km track. It is shown that the increasing MFP dependence
at high frequency and at longer ranges can only be accountted for by including
a time dependent modelling of the water column sound speed profile.