Some issues concerning numerical simulation as a predictive tool for assessing sonar performance in uncertain environments

Abstract

One goal of numerical simulation in ocean acoustics is the accurate prediction of acoustic field properties in complex environments. In this context, the objective assessment of both sonar performance and associated signal-processing schemes operating within uncertain littoral environments pose significant challenges for numerical simulation. Some of the issues involved with using numerical models for the prediction of sonar performance in the presence of incomplete environmental information are addressed. To achieve credibility as a prediction tool, the simulation results should be held to the same standards as those associated with experimental results, i.e., the numerical predictions should include error bars or confidence intervals that represent a quantitative measure of the environmental uncertainty that is always present. Providing a rational, quantitative assessment of system uncertainty in complex environments is a nontrivial task. Incomplete environmental information occurs at multiple space-time scales within both the oceanographic and acoustic modeling phases; this uncertainty can propagate, interact, and amplify in the course of transmitting and processing the signal. It is argued that environmental uncertainty should be directly incorporated into the numerical simulation process so that it links directly to the physics of wave propagation. [Work supported by NRL Base funding through ONR.]