Coherent interference suppression for near-field underwater acoustic imaging

For the near-field underwater acoustic imaging system, the performance of conventional focused beamforming technique can become severely degraded when the target echoes are obscured by directional coherent interferences. In this paper, the Bartlett beam null-forming is adopted to suppress such interferences. It can maximize the power output of targets directions and make beam output nulls in interferences directions. Numerical simulations are provided for demonstrating the validity of the presented method. And the results indicate that the Bartlett method can form nulls in the positions of one or more coherent interferences effectively and reduce the side lobe level.