SOSUS

SOSUS, an acronym for SOund SUrveillance System, was 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 targets in the Atlantic. Other locations in the Atlantic and Pacific Ocean also had SOSUS stations installed. It was later supplemented by mobile assets such as SURTASS becoming IUSS.

History

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. At the time the primary threat was diesel submarines, and it was known that the Soviets were in the process of building a large fleet. The group quickly decided that the solution to detecting these submarines was to use sound detectors that would use the SOFAR channel to detect low-frequency sounds from hundreds of kilometers. Each listening site consisted of multiple hydrophones and a processing facility. This then allowed them to estimate the submarine's position by triangulation. They allocated $10 million annually to develop these systems.

Research Phase

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 hydrophone 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 classified name SOSUS was first used. The number was increased to nine later in the year, and Royal Navy and USN ships, including USS "Neptune" and USS "Peregrine", 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 straits, called Project Colossus.

OSUS goes operational

In 1961 SOSUS tracked the USS "George Washington" from the United States 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 ashore. 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 Naval Facilities NAVFAC (not to be confused with Naval Facilities Command), existed on the US coastline at Adak AK, Pacific Beach WA, Coos Bay OR, Centerville Beach CA, Point Sur CA, and San Nicolas Island CA on the west coast and , Adak, AK, and Whidbey Island WA (1987) in the west and Nantucket, MA (the Tom Nevers Naval Facility), Lewes DE; Cape Hatteras NC and Puerto Rico on the east coast. Other NAVFACs were located in the Pacific at Honolulu HI, Midway Island, Guam and Japan, and in the Atlantic at Keflavik Iceland, Argentia Newfoundland, Nova Scotia, Brawdy Wales UK, Antigua, Barbados, Eluthera, Bermuda, Grand Turks, and San Salvador. Data Evaluation Centers were set up at Whidbey Island, WA and Dam Neck, VA in the early 1980’s.

LOFAR (frequency analysis) was carried out on the signals from the arrays and paper outputs of lofargrams produced, which were used to detect and classify contacts. When the USS Thresher sank in 1963 SOSUS helped determine its location. In 1968 the first detections of Victor and Charlie Soviet submarines were made, while in 1974 the first Delta was observed.

In 1985 the Fixed Distributed System test array became operational and the first SURTASS patrol began. There is a new name for the overall system, IUSS (Integrated Undersea Surveillance System). In 1991 the system mission was declassified and next year it began reporting whale detections and SOSUS Work Stations began replacing paper lofargrams. The Advanced Deployable System became operational as part of IUSS in 1996.

Current status

SOSUS was gradually condensed into a smaller number of monitoring stations during the 1970s 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 1990s, the immediate need for SOSUS decreased, and the focus of the US Navy also turned towards a system that was deployable on a theater basis. The SOSUS components are now being used for various scientific projects, such as tracking the vocalizations of whales and other ocean mammals in various study projects, as a data network for undersea instrumentation packages, and for acoustic thermometry. The SOSUS system was officially declassified in 1991, although by that time it had long been an open secret.

Regardless of the above entry, the IUSS is alive and well. Commander Undersea Surveillance (CUS) onboard the NAS Oceana Dam Neck Annex operates under the operational guidance of COMPACTFLT and the Center for Naval Meteorology (CNMOC). Naval Ocean Processing Facilities in Oak Harbor, Washington, and Virginia Beach, Virginia, still monitor SOSUS and FDS, and they provide SURTASS connectivity around the world.

See also

* Communication with submarines

External links

* [http://www.cus.navy.mil/timeline.htm History of IUSS: Timeline]
* [http://www.chinfo.navy.mil/navpalib/cno/n87/usw/issue_25/sosus.htm "SOSUS: The "Secret Weapon" of Undersea Surveillance"] , "Undersea Warfare", Winter, 2005, Vol. 7, No. 2, article by Edward C. Whitman
* [http://www.pmel.noaa.gov/vents/acoustics.html The Acoustic Monitoring Project]
* [http://www.chinfo.navy.mil/navpalib/cno/n87/history/cold-war-asw.html The Third Battle:] Innovation in the US Navy's Silent Cold War "(MIT: March, 2000)"
* [http://www.globalsecurity.org/intell/systems/sosus.htm Sound Surveillance System (SOSUS)] , GlobalSecurity.org
* [http://www.ldeo.columbia.edu/ldeo/alum/assoc/pgi.html A Letter from Joe Worzel to Lamont-Doherty Earth Observatory regarding the establishment of Palisades Geophysical Institute, its work, and support of the education and research community]
* [http://www.fas.org/irp/program/collect/sosus.htm The SOund SUrveillance System] , Federation of American Scientists, Intelligence Resource Program