Adaptive noise canceling applied to Sea Beam sidelobe interference rejection

An adaptive noise cancelling (ANC) technique involving a joint-process deterministic least-squares lattice filter was applied to the Sea Beam bathymetric survey system data. The filtering scheme used in Sea Beam adversely affects the underlying acoustic return and may also lead to bathymetric artifacts. The authors investigate a possible remedy for this sidelobe interference problem offered by ANC coupled with signal preservation, provided both amplitude and phase information. The joint-process deterministic least-squares lattice is the adaptive filter of choice because of its superior transit response in the presence of power discontinuities. A REVGEN (reverberation generator) simulation (R.P. Goddard, 1985) of the Sea Beam system provided support for the proposed filtering technique. A complex data acquisition system was designed and built to record the in-phase and quadrature component of Sea Beam returns. Initial ANC processing of these recorded Sea Beam data provided satisfactory sidelobe interference cancellation with no noticeable degradation of the actual bottom returns.<
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