ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2aUW16. Minimum variance matched-field source localization with SACLANT Mediterranean sea trial data.

Dept. of Elec. Eng., Duke Univ., Box 90291, Durham, NC 27708

The minimum variance (MV) adaptive beamformer has been widely proposed for matched-field processing because it provides a means of suppressing ambiguous beampattern ``sidelobes.'' In this paper, the performance of three robust MV methods is evaluated using vertical array data from the Mediterranean Sea collected by the NATO SACLANT Centre north of Elba [D. F. Gingras and P. Gerstoft, 3234 (1994)]. The three MV methods considered are (1) the reduced MV method (RMV) [C. L. Byrne et al., 2493--2502 (1990)], (2) the MV method with neighborhood location constraints (MV-NLC) [H. Schmidt et al., 1851--62 (1990)], and (3) the MV method with environmental perturbation constraints (MV-EPC) [J. Krolik, 1408--19 (1992)]. Real data results indicate that each approach has different merits. Projecting the data onto the reduced space defined by the modal eigenfunctions as in the RMV is necessary to avoid instabilities caused by highly correlated noise. Using neighboring location constraints as in the MV-NLC reduces the need to finely sample the ambiguity surface. And using constraints derived from the second-order statistics of the signal wavefront averaged over an ensemble of perturbed environmental parameters as in the MV-EPC increases robustness to environmental mismatch. [Work supported by ONR.]