13: Scattering from Rock and Rock Outcrops

In terms of target detection and classification, scattering from exposed rock on the seafloor, (i.e., individual rocks and rock outcrops) presents some of the most difficult challenges for modern MCM and ASW sonar systems in shallow water. Work on characterizing, modeling and simulating mean levels and other statistical measures of acoustic scattering from rocks and rock outcrops is therefore critical. Unfortunately (and curiously) information on scattering from underwater rock and outcrops is almost non-existent. Scattering from rock outcrops is not simple enough to be encompassed by a single scattering strength curve, but has a variety of expressions depending on the exact geomorphology of the rock. Smoothed surfaces may actually scatter less than surrounding sediment; curvature may dramatically affect scattering and rough areas as seen in the ‘plucked’ area on the rock outcrop in Fig. 1, display high variability which could pose difficulty for target detection and classification systems.