STATISTICAL MODELS OF REVERBERATION AND CLUTTER, I.
LITTON SYSTEMS INC WALTHAM MASS INFORMATION SCIENCES LAB
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A general phenomenological, statistical model of reverberation and clutter, based on Poisson processes, is constructed, generalizing and extending earlier results, and taking into account many of the detailed features of typical scattering mechanisms. These include the role of transmitting and receiving arrays, doppler effects, broad- and narrow-band illuminations, distributions of scatterers on surfaces and in volumes, reflectivities, the geometries of transmitter, receiver, and scatterers, etc. A hierarchy of characteristic functions and associated probability densities is derived, with particular attention to the various classes of process covariances, which completely describe these processes in the many cases when the scattering events are sufficiently dense that normal laws are obeyed. These processes are found to be inherently non-stationary, because of the distributed nature of the scattering elements, although quasi-stationarity may occur if illuminating signals of sufficiently short duration are used. Other new results include the statistics of correlated reverberation and clutter processes, which arise in split- and multi-beam systems when some portion of the illuminated scattering region is commonly viewed in the various beams. The results are generally applicable to radar, sonar, and seismic problems, particularly when the distributed nature of the scattering mechanisms and the space-time processing features of the receiving and transmitting spectrum must be explicitly considered. Author