The effects of a bottom‐limited ocean on signal kurtosis—Applications to tricorrelation detection and minimum entropy deconvolution of broadband signals

Abstract

As signals propagate in the ocean their temporal and spectral features vary as a function of space and time. This is especially true in bottom‐limited environments where the signal may encounter numerous boundary interactions with significant loss due to absorption. This environmental distortion can have a significant effect on the ability to detect and classify broadband signals. A broadband parabolic equation model is used to predict signal distortion over a 25–150‐Hz bandwidth in both range‐independent and downslope, bottom‐limited environments. Signal kurtosis is used to characterize signal distortion in range and depth. Comparisons are made between the kurtosis predicted by the model and that estimated from experimental data. It is shown that the model, together with good environmental information, can accurately predict signal kurtosis as a function of range and depth in the ocean. The significance of the variation of signal kurtosis is discussed in terms of the tricorrelation detector and minimum entropy deconvolution of broadband signals. [Work supported by Office of Naval Research, Program Element 61153N, with technical management provided by the Naval Research Laboratory.]