Subarray Beamforming for Reducing the Effect of Flow Noise on Sonar Arrays

Subarray beamforming has been identified as a signal processing technique to potentially reduce the effect of aerodyn amically induced flow noise against a target signal which is difficult to target with full array beamforming due to its near-field and non-stationary nature. Previously the technique had been proposed yet was not fully investigated nor adequately compared to its full array adaptive counterpart. In this study the nature of flow noise and its implications to the effectiveness of the subarray technique have been investigated through an idealised mathematical model. The result demonstrates the potential to achieve considerable array gains against traditional adaptive beamforming, heavily dependent on flow noise characteristics, and the choice of subarray configuration is justified by a trade-off in faster adaption times against the accuracy of the cross-spectral matrix estimate.