A robust passive interferometry technique for sediment geoacoustic characterization

Due to the dispersive characteristics of acoustic propagation in shallow water, the broad-band sound field excited by a passing ship usually exhibits an interference structure with the form of striations in the space-frequency plane. Waveguide invariant theory is derived to interpret the striation slope and has been used for underwater inverse problems including sediment geoacoustic characterization, source localization, target recognition and others. Owing to the interference structure processing methods previously used, most applications only use the overall striation slope as acoustic observable, however, the local striation structure that is also closely related to the environmental properties was not considered. In this paper, a passive acoustic interferometry technique is proposed for sediment geoacoustic characterization using local striation features extracted by a multi-scale line filter. Based on the Yellow Shark environmental model, a synthetic study using the proposed method is presented for sediment geoacoustic characterization. The robustness of the passive acoustic interferometry technique to source depth and range uncertainties are also studied by theory analysis and numerical simulation. Finally, the acoustic data due to passing ships collected in Mediterranean Sea in 2007 are processed to test the feasibility of the proposed method.