Sea beam sidelobe interference cancellation

The Sea Beam multibeam bathymetric system is in operation aboard research vessels worldwide. While it has contributed greatly in advancing the understanding of the deep-sea floor, several types of bathymetric artifacts have been identified in its contoured output which could be mistaken for sea floor structure. Among those, the "tunnel" effect results from sidelobe interference caused by the near specular return and is most prominent when the sea floor is relatively flat. It is characterized by a trough in the bottom profile produced by Sea Beam. It will be shown that this type of interference can be greatly reduced or eliminated through an adaptive filtering scheme, pending a minor modification of the Sea Beam data acquisition system. The noise-cancelling configuration of the adaptive least-squares lattice filter will be used to process simulated Sea Beam data obtained through REVGEN, a high-fidelity sonar system simulation program.