Near-field to far-field projection algorithm for free-field or buried scatterer.

A near-field to far-field projection algorithm is applied to a structure in the free-field case and generalized to a buried scatterer. The method of superposition is applied where the scattered field produced by the target may be approximated by the field produced by a number of point sources placed near the target. The source strengths are determined by requiring the field they produce to satisfy boundary conditions on the measurement surface.

At-sea measurements of sound penetration into sediments using a buried vertical synthetic array.

Acoustic bottom penetration experiments were carried out in a medium-grain sandy bottom at a site in St. Andrews Bay, Florida. These investigations used a new buried, vertical, one-dimensional synthetic array system where a small hydrophone was water-jetted into the sediment to a depth of approximately 2 m.