MATCHED FIELD PROCESSING USING MULTIPOLE EXPANSION

摘要

The underwater acoustic source field is expressed in terms of the multipole series which depends on source moments. This is a generalization of the monopole field representation which is used extensively in matched field processing. The generalization allows for acoustic sources with unknown higher-order moments. It is shown that including the dipole contribution into the source model may enhance the performance of matched field processing algorithms. Incorporating higher terms of the expansion leads to algorithms depending on spatial derivatives of the Green's function replica vector. The Green's function and its derivatives are computed using a normal-mode approach in this paper. The proposed approach is applied to acoustic data acquired with a towed array during a sea trial east of Bornholm in the Baltic Sea.