A very-wide-angle acoustic model for underwater sound propagation

A parabolic model, valid for wide angles (out to 90° from the assumed propagation direction for a homogeneous environment), is presented. Numerical computations for the model are done almost entirely in the Fourier domain, and the model can be shown to be theoretically exact for a homogeneous ocean. In addition, the model can implicitly handle range-dependent sound-speed profiles. An error analysis indicates that the model is more accurate than the standard parabolic equation (SPE) and the modified-wide-angle parabolic equation (MWAPE) for constant perturbations of the index of refraction. The accuracy of the model is examined by comparison of computed solutions with exact solutions for range independent cases. Several idealized range-dependent cases are also examined.