Range spread measurement of underwater scatterers and channels using active sonar probing signals and a cross-correlation process

Abstract

A method for measuring range spread of underwater scatterers and channels based on the cross-correlation processing of the tones of a multicomponent waveform has been developed. The correlation terms which comprise the measure are samples of the time-frequency correlation functions (TFCF) of scatterers and channels. The measure has been used to characterize the time-frequency spread and represents the signal coherence. This paper will provide a review of two frequency correlation function representations and their characterization using the aggregate coherence measure, termed correlation mass. The sensitivity of this measure as a function of waveform parameters, scatterer structure, and measurement platform motion will be defined and its robustness on a multiping basis assessed. It will be shown that this measure can be decomposed into correlated components resulting from interaction with a scatterer and a channel. Essentially the composite correlation is obtained by sampling the product of the scatterer and channel TFCF’s. Data from in-water experiments and digital sonar simulations will be presented which validates the linear systems model of the composite scattering process. [Work supported by ONR.]