Abstract:

It has been shown [R. A. Wagstaff, J. Acoust. Soc. Am. 100, 2853(A) (1996)] that extraordinary gains can be achieved in signal-to-noise ratio enhancement, spatial and spectral resolution can be increased, clutter can be reduced, and submerged sources can be detected by exploiting the natural amplitude fluctuations of the signal and noise. Natural amplitude fluctuations are those fluctuations induced during propagation through the undersea acoustic environment. The gains were achieved by biasing the signal processor, through the WISPR and AWSUM controlling equations, to operate at very low percentiles in the distributions. It is shown in this paper that it is not only possible to achieve additional fluctuation exploitation gains for fluctuation-based processors, such as WISPR and AWSUM, but it is also possible to convert conventional processors to fluctuation-based processors by appropriate modification using a fluctuation sensitive parameter such as the standard deviation. The method is discussed and examples are presented that demonstrate the gains that have been achieved. [Work supported by ONR and NRL.]