US Patent 7149149 Acoustic flow noise cancellation using a reference hydrophone

The present invention relates to a system and a method for substantially eliminating flow noise from the signal output of each hydrophone in a hull mounted acoustic array. The system comprises a plurality of hydrophones forming an acoustic array mounted to a hull of a marine vessel, at least one reference hydrophone mounted to the hull in a laminar region of fluid flow over the hull, and a computational device for generating an output signal for each hydrophone in the acoustic array which is substantially free of flow noise using signals inputted from the acoustic array hydrophones and the at least one reference hydrophone.