Modeling Swatch Bathymetry/Sidescan Sonar Image Returns

There are several systems in current use that collect bathymetric data across a swath under the ship, and simultaneously collect backscattering data similar to sidescan images. The bathymetric data allows for low spatial frequency descriptions of the bottom geomorphology and we argue here that the backscattering data can be analyzed to reveal statistical descriptions in fine- scale spatial frequency ranges determined by the sonar frequency. Included in the geomorphology would be the rms heights referred to as microroughness here in a wavelength band just shorter than a few acoustic wavelengths and rms slopes in a band from a few acoustic wavelengths to the size of the sonar footprint. For the purposes of this work, it is assumed that all the scattering is attributed to roughness at the watersediment boundary. We propose to use the information content in the backscattering strength versus incident angle curve to extract this information. Extracting these parameters, requires a valid scattering model that incorporates them. Ideally, this model would be simple enough to use in real-time as a bathymetric survey progresses.