1aAO5. Robust ray path identification for ocean acoustic tomography.

Session: Monday Morning, May 13

Time: 9:05

Author: Max Deffenbaugh
Location: Dept. of Elec. Eng. and Comput. Sci., MIT, Cambridge, MA 02139
Author: Henrik Schmidt
Location: MIT, Cambridge, MA 02139
Author: James G. Bellingham
Location: MIT Sea Grant, Cambridge, MA 02139


Acoustic tomography in a ray environment is a two-step process. First, each measured ray arrival time in the received multipath structure is identified with a particular predicted ray path. Second, the differences between the measured arrival times and the predicted arrival times for the represented ray paths are used in a linear inversion to calculate corrections to parameter values describing the sound-speed structure. If measured arrival times are identified with the wrong ray paths, errors will result in the linear inversion. In deep ocean tomography, the time spacing between ray arrivals is typically large compared to the parameter induced changes in arrival times, so ray path identification is not difficult. In shallow water, however, ray path identification can be more challenging. An algorithm is presented that combines the ray path identification step with the linear inversion step to allow tomography using rays where the parameter induced arrival time shifts may be larger than the time spacing between arrivals. The performance of the algorithm is simulated for a typical shallow-water environment. [Work supported by ONR.]

from ASA 131st Meeting, Indianapolis, May 1996