Book Description

A general approach to scattering phenomena is developed and applied specifically to underwater acoustic scattering situations involving the medium and its interfaces. The fundamental elements of the method are the development of the available scattering elements into a hierarchy of independent scatter processes, based on the scatterers activated, at any given instant. This, with the governing class of Langevin equation (e.g., forms of the (scalar) wave equation here) permits a corresponding development, in linear superposition, of the received, scattered field x sub m as a hierarchy of independent processes, x sub m(k), k=0,1,2., representing different scales of inhomogeneity which may be present in the medium, or upon its interfaces. First- and second-order moments (covariances and generalized spectra) are obtained in canonical form, representing global properties of the channel and the local properties of the medium itself. A number of probability densities are also obtained in important limiting cases, e.g. various (conditional) normal p.d.f.'s. Part I concludes with some remarks on an experimental program, designed to test and quantify various aspects of the general model, both for studies of the medium itself (and its associated interfaces), and for the broad class of statistical communication applications, such as detection, extraction, classification, communications per se, as well as signal and aperture design problems