IUSS, SOSUS, and mobile towed-array surveillance

The Integrated Undersea Surveillance System is likened to an oceanic early-warning network. Fixed SOSUS arrays monitor strategic passages such as the GIUK Gap, while SURTASS ships tow very large arrays beyond major shipping lanes to add depth and mobility. These sensors hear entire ocean regions rather than one selected target, producing more data than operators can examine contact by contact. Accurate acoustic profiles and machine-assisted search methods help separate submarines from the background and prioritize follow-up patrols. Centralization and reduced shore infrastructure may save money, but they may leave too little resilient capacity for wartime.