Robust matched field noise suppression for towed line array

For a towed line array sonar system, tow ship noise is a kind of wideband interference with strong multi-path and angle dispersion. The cancellation of the multipath interference is a challenge. Based on the novel concept of Matched Field Noise Suppression (MFNS) proposed by the authors, this paper discusses two robust MFNS beamformers. One is Multiple Constraints MFNS (MC-MFNS) and the other is Matched Field Postbeamformer Interference Canceller (MF-PIC). Closed-form solutions of the two robust methods are given and some details are discussed. The prominent advantage of the methods is that they can be used to cancel the tow ship noise for all arrival directions and keep signal power with robustness.