Patent ID: 6876598

Claim:
A computer implemented method for predicting propagation of a wave in a medium, said medium bordering a top reflective surface and a bottom reflective surface, said method comprising the steps of: (a) selecting a direction in which predictions of said propagation are desired; (b) selecting a pair of transparent boundaries that are parallel to said direction; (c) selecting a plurality of range steps in said direction; (d) calculating a plurality of local modes between said transparent boundaries and at said range steps; (e) calculating a plurality of coupling coefficients between said transparent boundaries and at said range steps; (f) selecting a plurality of modal amplitudes between said transparent boundaries and at said range steps; (g) splitting said modal amplitudes into a plurality of primary components and a plurality of secondary components; (h) selecting a plurality of initial values for said modal amplitudes at a first one of said range steps; (i) using a decomposition method to predict said modal amplitudes between said transparent boundaries and at said range steps from said initial values, said decomposition method including (1) using a coupled-parabolic-equation method with said coupling coefficients to predict boundary values of said primary components at an arbitrary range step from said modal amplitudes and said secondary components at a preceding range step, (2) using a parabolic-equation method to predict said secondary components at said arbitrary range step from said boundary values and from said secondary components at said preceding range step, (3) using said coupled-parabolic-equation method with said coupling coefficients to predict said modal amplitudes at said arbitrary range step from said secondary components at said arbitrary range step and from said modal amplitudes and said secondary components at said preceding range step, j) determining mathematically said propagation of said wave from said local modes and from said modal amplitudes.