In-situ estimates of environmental uncertainty on sonar performance prediction

Abstract

Oceanographic and geo-acoustic variability in the shallow water can dominate acoustic propagation. Sonar performance predictions using archival sound speed and geo-acoustic information do not contain any information about variability or uncertainty in the environment and its likely impact on sonar performance prediction. Using measurements from the NATO Undersea Research Centres BOUNDARY 2003 sea test, an approach is presented that estimates the uncertainty and transfers it through the acoustic propagation and the sonar equation to sonar performance. The sound speed field is characterized by an Empirical Orthogonal Function decomposition of the measured profiles. The geo-acoustic uncertainty is considered to be a normal distribution around the inverted geo-acoustic parameters (from 4 separate inversions). Dynamic ambient noise variability is measured from the array beamformer output. Uncertainty in propagation is quantified in terms of sound speed, geo-acoustic, and ambient noise uncertainty. The uncertainty in sonar performance, due to environmental uncertainty, is then displayed to the operator. [Work supported by the ONR Capturing Uncertainty DRI.]