GEOMETRIC AND RADIOMETRIC CORRECTION OF MULTIBEAM BACKSCATTER DERIVED FROM RESON 8101 SYSTEMS

A common by-product of multibeam surveys is a measure of the backscattered acoustic intensity from the seafloor. These data are of immense interest to geologists and geoscientists since maps of the acoustic backscatter strength can be used to infer physical properties of the sea bottom, such as impedance, roughness and volume inhomogeneity. Before such maps can be created from multibeam acoustic backscatter data, however, two tasks must be performed: 1. The data must be geographically registered using the bathymetric profile collected by the multibeam (which accounts for full orientation and refraction), as opposed to using the traditional flat-seafloor assumption. This allows us to additionally calculate the true grazing angle. 2. The signal intensities must be reduced to as close a measure of the backscatter strength of the seafloor as possible by radiometrically correcting the data on a ping-by-ping basis for variables such a