Passive detection in deep water using the reliable acoustic path.

Abstract

The detection of quiet targets in deep water environments is of increasing interest for Navy applications, and detection performance depends critically on efficiently exploiting the frequency-dependent signal and noise structure. Previous measurements in the deep ocean environment of the northeast pacific has demonstrated the significant depth and frequency dependence of the noise, which can also vary with local wind conditions [Gaul et al., IEEE JOE (2007)]. The signal structure depends both on the spectrum of the target itself, but also on the propagation characteristics of the channel. In the concept of a reliable acoustic path (RAP), a receiver placed at or below the critical depth can detect shallow sources out to moderate ranges independent of near-surface water conditions or bottom interaction (hence, the identification as a “reliable” path). In this presentation, we present analysis of noise and signal structure for deep water channels from historic data, propagation modeling, and more recent experimentation. This structure is then used to compute signal excess to quantify detection performance as a function of receiver array placement and topology. Implications of the results on future Navy systems is discussed.