The measure of environmental sensitivity in detection performance degradation

It is known that environmental mismatch in an uncertain ocean can cause performance degradation to sonar detection algorithms. However, there has been relatively little work in defining practical quantitative measures of environmental sensitivity. In previous studies, mismatch analysis was mainly performed on matched field processing for target localization. Environmental sensitivity for ocean acoustic propagation has also been studied where the acoustic field's pressure amplitude variation was considered. Based on these facts, this paper defines a measure of environmental sensitivity in the degradation of detection performance, in order to account for realistic uncertainties in various environmental parameters. Sensitivity is here defined for two detectors. One is the optimum detector in the deterministic ocean environment and another is the optimum Bayesian detector in the uncertain ocean environment. The Malta Plateau, a well-studied shallow-water region of the Mediterranean Sea, is used to perform the detection performance degradation sensitivity analysis. The result shows that (1) the sensitivity is range-and depth-dependent, and its value in the sound channel is much smaller compared to other regions of the ocean; (2) the optimum detector derived for the deterministic environment may suffer a great detection performance degradation when applied to the uncertain environment; and (3) the water-column sound-speed profile and the upper seabed layer are the most sensitive parameters for the degradation of detection performance.