ASA 125th Meeting Ottawa 1993 May

2aAO10. Shallow-water broadband source localization in range and bearing by matched fields.

David P. Knobles

Stephen K. Mitchell

Appl. Res. Labs., Univ. of Texas at Austin, P.O. Box 8029, Austin, TX 787123

Data from a moving source received by three horizontally separated bottomed sensors in a shallow-water environment are analyzed using a broadband matched-field approach to source localization. The water depth was approximately 120 m, and the low bottom loss in the area results in low spatial coherence of the broadband field. The modeled acoustic fields are constructed via a ray model with wave-like corrections. Localizations are made in the x-y plane. The time evolution of the matched-field surfaces produced from the data agree well with simulated surfaces. Matched-field surfaces are generated successively in intervals of about 1.6 s in small search areas with a fine spatial grid to test the possibility of tracking a source. Results of the source tracking will be presented. The analysis also considers the effects of the sea floor and environmental mismatch of sea floor descriptions on localization in the context of spatial coherence. In addition the effect of varying the receiver separation on the ability to make a localization when a source is in the ``broadside'' region of the array is discussed. [This work is supported by the Office of Naval Research, Code 23, through Block RL3B.]