Abstract:

There are scenarios of interest in which the signals have smaller fluctuation amplitudes than the clutter and noise. When this is the case, it has been shown [R. A. Wagstaff, J. Acoust. Soc. Am. 100, 2853(A) (1996)] that extraordinary gains can be achieved by signal processors that are designed to discriminate according to fluctuation amplitude. It is also possible to achieve similar gains from processors that are designed to discriminate based on the temporal order dependence of the fluctuations. Since this temporal order-dependent processor is unrelated to other order-independent fluctuation-based processors such as WISPR and AWSUM, the gains can be increased by combining the methods. This order-dependent fluctuation-based signal processor will be described, and the gains including signal-to-noise ratio enhancement, clutter reduction, and unalerted-automatic detection will be discussed. The results will be illustrated using measured data. In addition, results from combining the two different fluctuation-based processing methods, order dependent and order independent, to achieve additional gain will also be presented. [Work supported by ONR and NRL.]