5aUW2. Relaxation techniques for finding horizontal eigenrays for global scale propagation.

Session: Friday Morning, December 6

Time: 8:16

Author: Kevin D. LePage
Location: BBN Acoust. Technologies, 70 Fawcett St., Cambridge, MA 02138


Prediction of the localization performance of a global hydrophone network requires the rapid computation of horizontal eigenrays connecting receivers to a grid of hypothetical source locations. The computation of these eigenrays using shooting techniques can be time consuming. For many of the paths, the refracted geodesic can be quite close to the horizontally refracted ray. In these cases relaxation techniques can be successfully used to bend the geodesic trial solutions onto the refracted path. This technique, which involves the iterative solution of a block diagonal system of equations, offers substantial performance benefits. Work by Collins et al. [J. Acoust. Soc. Am. 95, 3167--3170 (1994)] also suggests that relaxation techniques are useful for avoiding shooting problems associated with sensitivity to initial conditions, a common problem when shooting rays near shoaling bathymetry. Comparisons between traditional shooting eigenrays and the relaxed eigenrays are made and conclusions regarding the range of applicability of the relaxation technique are presented. [Work supported by DOE and Air Force Phillips Laboratory.]

ASA 132nd meeting - Hawaii, December 1996