Understanding deep-water striation patterns and predicting the waveguide invariant as a distribution depending on range and depth.

The Waveguide Invariant (WI) theory has been introduced to quantify the orientation of the intensity interference patterns in a range-frequency domain. When the sound speed is constant over the water column, the WI is a scalar with the canonical value of 1. But, when considering shallow waters with a stratified sound speed profile, the WI ceases to be constant and is more appropriately described by a distribution, which is mainly sensitive to source/receiver depths.

Sub-antenna processing for coherence loss in underwater direction of arrival estimation.

This paper deals with the loss of coherence in underwater direction-of-arrival estimation. The coherence loss, which typically arises from dynamical ocean fluctuations and unknown environmental parameters, may take the form of a multiplicative colored random noise applied to the measured acoustic signal. This specific multiplicative noise needs to be addressed with methodological developments.