Three-dimensional eigenray search for a vertical line array

Abstract

Eigenray search in a two-dimensional waveguide is a feasible task, that can be solved efficiently through optimization of an ad hoc defined function (like, for instance, final ray depth deviation from hydrophone depth) over original ray elevations; in the worst case even when rays can be reflected backwards to the source an exhaustive search over the ray trajectory can be able to identify eigenrays by testing the proximity of each ray to the hydrophone. In three-dimensional waveguides the situation is far more complicated: the proximity method can be found to be very inefficient due to out-of-plane propagation and optimization needs to be developed over the plane of ray elevations and azimuths. The work presented here addresses the three-dimensional search of eigenrays based on the simplex method, implemented in a recent ray model; the performance of the method is discussed through comparisons with experimental data for a vertical line array.