SOSUS, an acronym for SOund SUrveillance System, is a chain of underwater listening posts located across the northern Atlantic Ocean near Greenland, Iceland and the United Kingdom—the so-called GIUK gap. It was originally operated by the U.S. Navy for tracking Soviet submarines, which had to pass through the gap to attack shipping in the Atlantic. Other locations in the Atlantic and Pacific Ocean also had SOSUS stations installed.

SOSUS development was started by the Committee for Undersea Warfare in 1949. This panel was formed by the Navy, in order to further research into anti-submarine warfare when the main concern was snorkeling diesel submarines. This group quickly decided that the solution was to use low-frequency sound detectors that would detect engine sounds from hundreds of kilometres. Each listening site consisted of multiple detectors. This then allowed them to estimate the submarine's position by triangulation. They allocated $10 million annually to develop these systems.

Project Hartwell

At MIT during 1950, the committee sponsored Project Hartwell, named for the director of the committee, Dr. G.P. Hartwell, professor at the University of Pennsylvania. In November,they selected Western Electric to build a demonstration system, and the first six element array was installed on the island of Eleuthera in the Bahamas. Meanwhile Project Jezebel at Bell Labs and Project Michael at Columbia University focused on studying long range acoustics in the ocean.

By 1952 such progress had been made that top secret plans were made to start deployment of six arrays in the North Atlantic basin, and the name SOSUS was first used. The number was increased to nine later in the year, and Royal Navy and USN ships started laying the cabling under the cover of Project Caesar. In 1953 Jezebel's research had developed an additional high-frequency system for direct plotting of ships passing over the stations, intended to be installed in narrows and straights.

SOSUS goes operational

In 1961 SOSUS tracked the USS George Washington from the United States all the way to the United Kingdom. The next year it tracked the first Soviet diesel submarine to be detected using the system. Later that year the SOSUS test system in the Bahamas was able to track a Soviet Foxtrot class submarine during the Cuban Missile Crisis. SOSUS underwent a number of upgrades over the years, as the quality of the opposing submarines increased.

SOSUS systems consisted of bottom mounted hydrophone arrays connected by underwater cables to facilities on shore. The individual arrays are installed primarily on continental slopes and seamounts at locations optimized for undistorted long range acoustic propagation. The combination of location within the ocean and the sensitivity of arrays allows the system to detect acoustic power of less than a watt at ranges of several hundred kilometers. SOSUS monitoring stations, known as NAVFACs, existed in the US west and east coasts, Keflavik (in Iceland), Antigua, Barbados, Brawdy (in Wales, UK), Puerto Rico, Argentia (in Newfoundland), and Grand Turks.

Pioneering alternative futures

SOSUS was gradually condensed into a smaller number of monitoring stations during the 70s and 80s. However, the SOSUS arrays themselves were based upon technology that could only be upgraded irregularly. With the ending of the Cold War in the 1980s, the immediate need for SOSUS decreased, and the focus of the US Navy also turned towards a system that was deployable on a theatre basis. The SOSUS components are now being used for various scientific projects, such as tracking the vocalizations of whales in various study projects, and as a data network for undersea instrumentation packages. The system was officially declassified in 1991, although by that time it had long been an open secret.

External links

---

• SOSUS: The "Secret Weapon" of Undersea Surveillance", Undersea Warfare, Winter, 2005, Vol. 7, No. 2, article by Edward C. Whitman
• The Acoustic Monitoring Project
• The Third Battle: Innovation in the US Navy's Silent Cold War (MIT: March, 2000)
• Sound Surveillance System (SOSUS), GlobalSecurity.org

Sonar | Anti-submarine warfare | Physical oceanography | 5-letter acronyms

Sound Surveillance System | Sound Surveillance System