John S. Perkins
Laurie T. Fialkowski
Michael D. Collins
W. A. Kuperman
Timothy L. Krout
Jon Jannucci
Naval Res. Lab., Washington, DC 20375
Ross F. Barrett
L. J. Kelly
Ashley Larsson
Defence Sci. and Technol. Organization, Salisbury, SA, Australia
Lindsay Hall
Defence Sci. Establishment, Auckland, New Zealand
John A. Fawcett
Anthony Hoffmann
Defence Res. Establishment Pacific, Victoria, BC, Canada
Preliminary results will be presented for the second TTCP Environmental Signal Processing Exercise (TESPEX 2), which was conducted in June 1994 in shallow waters north of Darwin, Australia. There were two objectives: (1) demonstrate improvements in environmental source tracking [Collins et al., J. Acoust. Soc. Am. 94, 3335 (1993)] (a single-frequency, single-hydrophone synthetic-aperture tracking technique) by relying on a second, horizontally separated hydrophone, and (2) determine the horizontal resolution the environment provides to a vertical array through matched-field processing [Perkins and Kuperman, J. Acoust. Soc. Am. 87, 1553 (1990)]. The approach was to first characterize the region by towing a high-SNR source throughout the region and measure the replica fields using two vertical line arrays separated by several kilometers (one with 32 elements, the other 4 elements), and then to use this data to form the replicas needed to track the source as it traversed the region alone a variety of tracks. The measured replicas are supplemented by modeled replicas; the environment used in the modeling is determined by inverting the measured data. We present preliminary processing results relevant to both objectives, including environmental inversions and tracking with measured and modeled replicas. [sup a)]Present address: Scripps Institution of Oceanography, La Jolla, CA 92093.