Sound Surveillance System (SOSUS) was the original name for a submarine detection system based on passive sonar developed by the United States Navy to track Soviet submarines. The system's true nature was classified with the name and acronym SOSUS classified as well. The unclassified name Project Caesar was used to cover the installation of the system and a cover story developed regarding the shore stations, identified only as a Naval Facility (NAVFAC), being for oceanographic research. The name changed to Integrated Undersea Surveillance System (IUSS) in 1985, as the fixed bottom arrays were supplemented by the mobile Surveillance Towed Array Sensor System (SURTASS) and other new systems. The commands and personnel were covered by the "oceanographic" term until 1991 when the mission was declassified. As a result, the commands, Oceanographic System Atlantic and Oceanographic System Pacific became Undersea Surveillance Atlantic and Undersea Surveillance Pacific, and personnel were able to wear insignia reflecting the mission.
A small waterplane area twin hull, better known by the acronym SWATH, is a catamaran design that minimizes hull cross section area at the sea's surface. Minimizing the ship's volume near the surface area of the sea, where wave energy is located, minimizes a vessel's response to sea state, even in high seas and at high speeds. The bulk of the displacement necessary to keep the ship afloat is located beneath the waves, where it is less affected by wave action. Wave excitation drops exponentially as depth increases, so wave action normally does not affect a submerged submarine at all. Placing the majority of a ship's displacement under the waves is similar in concept to creating a ship that rides atop twin submarines.
The Japan Maritime Self-Defense Force, abbreviated JMSDF, also simply known as the Japanese Navy, is the maritime warfare branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. The JMSDF was formed following the dissolution of the Imperial Japanese Navy (IJN) after World War II. The JMSDF has a fleet of 154 ships, 346 aircraft and 50,800 personnel.
HMNZS Resolution (A14) was a hydrographic ship of the Royal New Zealand Navy (RNZN). Originally the United States Naval Ship USNS Tenacious (T-AGOS-17), the Stalwart-class ocean surveillance ship was used by the United States to locate and track Soviet submarines from 1989 to 1997, when she was transferred to the RNZN for use as a hydrographic survey ship. She served until 27 April 2012. She was subsequently sold to EGS Group, a private surveying company, and renamed RV Geo Resolution.
USNS Stalwart (T-AGOS-1) was a Modified Tactical Auxiliary General Ocean Surveillance Ship and the lead ship of her class.
USNS Invincible (T-AGM-24), also known as ex-AGOS 10, is one of two tracking ships operated by the Military Sealift Command. One of the radars it carries is the Cobra Gemini dual band, X band and S band, radar.
The Hatsuyuki-class destroyer is a class of destroyer, serving with the Japan Maritime Self-Defense Force (JMSDF). It was the first class of first generation of general-purpose destroyers of the JMSDF.
The AN/UQQ-2 Surveillance Towed Array Sensor System (SURTASS), colloquially referred to as the ship's "Tail", is a towed array sonar system of the United States Navy.
USNS Triumph (T-AGOS-4) is a Stalwart-class ocean surveillance ship formerly of the United States Navy. She was struck from the Naval Vessel Register in 1995. On 1 October 2012 the ship was disposed of by Navy title transfer to the Maritime Administration. As of May 2015, Triumph was held as a reserve asset for spare parts for sister ships General Rudder and State of Michigan.
NRP Almirante Gago Coutinho (A523) is a ship of the Portuguese Navy' Dom Carlos I-class survey vessels. Before transfer to the Portuguese Navy, Almirante Gago Coutinho was formerly USNS Assurance (T-AGOS-5) of the United States Navy.
USNS Indomitable (T-AGOS-7) was a United States Navy Stalwart-class ocean surveillance ship in service from 1985 to 2002. From 2003 until 18 June 2014, she was in commission in the National Oceanic and Atmospheric Administration (NOAA) as the oceanographic research ship NOAAS McArthur II. As of 2018 it serves as a mother ship now named the Deep Submersible Support Vessel (DSSV) Pressure Drop for the crewed deep-ocean research submersible DSV Limiting Factor.
USNS Titan (T-AGOS-15) was a Stalwart-class modified tactical auxiliary general ocean surveillance ship in service in the United States Navy from 1989 to 1993. From 1996 to 2014, she was in commission in the National Oceanic and Atmospheric Administration (NOAA) fleet as the oceanographic research ship NOAAS Ka'imimoana.
USNS Capable (T-AGOS-16) was a Stalwart-class modified tactical auxiliary general ocean surveillance ship of the United States Navy in service from 1989 to 2004. In 2008, she was commissioned into service in the National Oceanic and Atmospheric Administration as the oceanographic research ship NOAAS Okeanos Explorer.
USNS Relentless (T-AGOS-18) was a Stalwart-class modified tactical auxiliary general ocean surveillance ship in service in the United States Navy from 1990 to 1993. Since 1998, she has been in commission in the National Oceanic and Atmospheric Administration (NOAA) fleet as the fisheries research ship NOAAS Gordon Gunter.
Geophysical MASINT is a branch of Measurement and Signature Intelligence (MASINT) that involves phenomena transmitted through the earth and manmade structures including emitted or reflected sounds, pressure waves, vibrations, and magnetic field or ionosphere disturbances.
USNS Able (T-AGOS-20) is a Victorious-class oceanographic survey ship in the service of the United States Navy's Military Sealift Command.
USNS Impeccable (T-AGOS-23) is an Impeccable-class ocean surveillance ship acquired by the U.S. Navy in 2001 and assigned to Military Sealift Command's Special Missions Program.
The Hibiki-class ocean surveillance ship is a class of surveillance ships operated by the Japan Maritime Self-Defense Force (JMSDF). The ships have a small-waterplane-area twin hull (SWATH) design.
JS Harima (AOS-5202) is a Hibiki-class ocean surveillance ship of Japan Maritime Self-Defense Force (JMSDF).
JS Aki (AOS-5203) is a Hibiki-class ocean surveillance ship of Japan Maritime Self-Defense Force (JMSDF).
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