The US Ocean Surveillance Systems emerged during the Cold War to track and monitor global maritime movements and activities. With oceans covering 70% of the earth’s surface, these advanced systems operate across multiple domains: land, sea, air, and space. Designed to detect threats, provide real-time data, and enable operations ranging from anti-submarine warfare and maritime Intelligence, Surveillance, and Reconnaissance (ISR) to strategic deterrence, these systems are a crucial component of US national security. 

Images Sourced From: Lt. James Caliva

1 History and Background 

1.1 World War II

During the Second World War, the US Navy fell behind in anti-submarine operations, largely due to limited knowledge of the oceanographic and acoustic conditions, particularly off the continental coasts. By contrast, the German Navy understood the Atlantic Ocean’s complex underwater environment much better. [source]

Since the war, the US Navy has thus endeavoured to carry out ongoing oceanographic research and extensive seabed mapping to improve its comprehension of environmental variables. Amongst other factors, this primarily includes currents, temperature, salinity, all of which influence how sound travels through seawater. [source]

1.2 During the Cold War 

1.2.1 Early Cold War Decades

By the early 1950s, however, the submarine threat had not disappeared; a new danger had emerged. Drawing on advanced German WWII technology, Soviet submarines became a growing security concern beneath the waves. Utilising the recently discovered SOFAR (SOund Fixing and Ranging) channel, a layer in the ocean that allows low-frequency sound to travel great distances, the Office of Naval Research (ONR) funded an undersea surveillance system to detect and track Soviet submarines. The programme, initially code-named Project Jezebel, later evolved into the SOund Surveillance System (SOSUS). [source]

The SOSUS installation involved positioning hydrophones on the ocean floor on the edge of the continental shelf, connected by cables to shore-based processing centres called Naval Facilities (NAVFACs). Specialised instruments called Low Frequency Analysis and Recording (LOFAR) were installed at NAVFACs to analyse low-frequency underwater sounds. In doing so, this allowed the distinctive sound signatures of submarines to be seen in LOFAR-grams. The first SOSUS programme was deployed off the island of Eleuthera, Bahamas in 1952. By 1954, the system was extended to the West Coast and Hawaii. [source]

1.2.2 The 1970s

The 1970s marked a pivotal decade in the expansion of US maritime surveillance systems. Central to this growth was the establishment of the US Navy’s Ocean Surveillance System (OSIS), which comprised of a Naval Ocean Surveillance Information Centre (NOSIC), three Fleet Ocean Surveillance Information Centres (FOSIC), and two Fleet Ocean Surveillance Information Facilities (FOSIF). [source, source] 

The OSIS, supported by its global network of sound surveillance facilities (SOSUS), ocean surveillance satellites, and ship-based and airborne sensor systems, was largely tasked to concentrate on the Soviet Navy and consisted of “personnel, facilities, computers, communications, and procedures designed to receive, process, correlate, and disseminate evaluated ocean surveillance information”. By the mid-1970s, the SOSUS system had expanded to include 20 NAVFACs, two Ocean Systems commands, and around 3,500 personnel, reflecting the increasing presence of Soviet submarines in the North Atlantic Ocean. [source, source]  

1.2.3 Late Cold War Decades

By the 1980s, US ocean surveillance capabilities had improved substantially. This was largely aided by the addition of satellites in low earth orbits which helped detect and record electronic emissions from vessels. By the end of the Cold War, however, the ability to detect and track Soviet nuclear submarines at long ranges had declined substantially as Russian submarine technology had become quieter. As a result, many SOSUS systems in the north Pacific were closed in the early 1990s.   [source, source]

2 Land 

Land-based surveillance systems are crucial in processing, disseminating, and sometimes collecting surveillance data. Land-based stations assist in processing data from both SOSUS hydrophone arrays from the sea, but also satellite signals from space such as the Classic Wizard land base network for the PARCAE satellites, located both in the US and overseas. [source]   

Companies such as Controp and Hensoldt assist the US military by providing high-level technologies to advance their surveillance capabilities and mission. For example, Controp offers a range of advanced sensor systems designed to strengthen coastal and border surveillance, counter-UAS operations, force protection, and critical site protection, using advanced EO/IR systems and multi-spectral sensors. With advanced technological devices, Controp provides long-range threat detection capabilities around the clock and in all weather conditions. [source]

3 Sea

Sea-based platforms play a key role in US surveillance and combat operations in the maritime domain. Submarines are especially versatile, delivering a broad spectrum of capabilities from anti-submarine and anti-surface ship warfare to precision land strikes, mine deployment, intelligence gathering, surveillance, early warning signals, and special operations. The US Pacific Submarine Force (SUBPAC) thus remains critical in this framework. SUBPAC operates an array of submarines and missile systems throughout the Pacific Ocean while also contributing to strategic deterrence under US Strategic Command. [source]

3.1 A few examples: 

3.2.1 Tactical Auxiliary General Ocean Surveillance (T-AGOS) Ships

In 2022, the US Navy obtained an array of larger, faster surveillance ships known as T-AGOS 2025. Today, these ocean surveillance ships form a key component of sea-based surveillance. These vessels conduct Surveillance Towed Array Sensor System (SURTASS) operations overseen by Military Sealift Command. T-AGOS ships support the anti-submarine warfare mission by gathering underwater acoustic data. By carrying electronic equipment, the T-AGOS ships then process and transmit the data gathered via satellite to onshore stations. [source]

3.2.2 Uncrewed Systems: 

The US Navy increasingly employs uncrewed naval vessels in the maritime domain. These include uncrewed underwater vehicles (UUVS), underwater mine hunting systems, uncrewed aerial vehicles, and many more. [source]

For example, Northrop Grumman, a force multiplier for the US Joint Forces, offer a series of advanced UUVs. These include the Manta Ray, utilised for long-range, long-duration missions, the Scion/Helix, the Fire Scout, a combat-proven, autonomous helicopter system delivering real-time intelligence, and the AQS-24B/C Minehunting vessel, the fastest fielded mine hunting system in the world. [source]

3.2.3 Precise Undersea Imagery: the Micro-SAS (synthetic aperture sonar)

Northrop Grumman also provides the µSAS™ (micro-SAS). This is a synthetic aperture sonar for underwater vehicles that captures precise, high-resolution imagery of the ocean and sea-bed. Due to its low size, weight, power, and adaptability to support missions from shallow water to full ocean depth, the micro-SAS is hugely versatile. Therefore, the micro-SAS greatly enhances ocean surveillance as it can function on many platforms from small UUVs to submarines. [source]

4 Air

Airborne platforms provide essential capabilities such as command and control, surveillance, and reconnaissance. 

4.1 A few examples: 

4.1.1 The E-2D Advanced Hawkeye: 

The E-2D Advanced Hawkeye is a combat-proven Airborne Command and Control surveillance platform which is rooted in the defence of a carrier battle group against long range bombers over water. This aircraft delivers decision dominance through battlespace awareness over air, land, and sea. Its advanced design has evolved to identify and deter threats in various environments for extended durations of time. The E-2D supports net-centric carrier strike groups, providing air and missile defence, and multiple sensor fusion capabilities. Due to its advanced technology and high performance, the E-2D was rated in the top five acquisition programmes by the US Navy in 2025. [source]

[source]

4.1.2 The MQ-4C Triton 

This high-altitude, long-endurance uncrewed aircraft provides persistent and reliable Intelligence, Surveillance, and Reconnaissance (ISR). The Triton detects, tracks, and classifies objects quickly and safely and is able to  fly at altitudes over 50,000 ft for over 24 hours at a time. This allows the aircraft to operate beyond surface threats and above weather and commercial traffic. A single Triton can cover nearly 4.2 million square nautical miles of ocean in a single flight. Its sensor suite includes a multi-functional advanced radar, electro-optical infrared sensor, and a full signal intelligence suite. [source]

4.1.3 The E-6B Mercury and E-130J TACAMO

The E-6B Mercury aircraft currently supports the US Strategic Command’s Airborne Command Post in addition to the very low frequency TACAMO relay mission. This mission maintains survivable communication links between key US decision-makers and the triad of strategic weapon delivery systems. For example, the communication channel between the National Command Authority and ballistic submarines. [source]

4 Space

Throughout the history of US ocean surveillance, space-based systems have provided cutting-edge developments and wide-range capabilities. Indeed, for many years, the Naval Ocean Surveillance System (NOSS) has utilised constellations of satellites in low earth orbits (LEOs) to detect and record the electronic emissions from vessels at sea. These were particularly useful in monitoring Soviet ships and submarines during the Cold War, orbiting at an altitude of roughly 450 kilometres. [source]

Notable early examples include the White Cloud, Parcae, and Improved Parcae satellite constellations. These were supported by ground stations known as Classic Wizard and developed by the Naval Research Laboratory in Washington, DC. The US launched the final satellite constellation in 1996, terminating the programme officially in 2008. The project, however, remained classified until late 2023. Reports indicate these satellite constellations were later replaced by more advanced systems that remain classified to the public. [source]

Today, the US Navy uses LEO ELINT satellites, launched in 2001. These more advanced models detect and record land-based radars and other electronic and sea-based emissions. According to the National Environmental Satellite, Data, and Information Service (NESDIS), NOAA owns and operates eight satellites including five geostationary, two polar-orbiting, and one deep space satellite. In addition, NOAA operates seven other satellites including the Suomi NPP, Jason-3, three Defence Meteorological Satellite Program (DMSP) satellites, and the EWS-G1 and EWS-G2. [source, source] 

5 The Future 

As demonstrated by companies such as Northrop Grumman and Airbus, the US Navy continues to advance its ocean surveillance capabilities through cutting-edge technology and procurements. 

Further efforts are underway to optimise the process from satellite tasking and image capture to analysis and information delivery. Northrop Grumman is heavily investing in digital engineering techniques and advanced manufacturing to rapidly design, build, test, and sustain future systems like the E-130J. Equally, Airbus has outlined future goals to use satellite imagery to detect oil spills and icebergs. [source]

Moreover, in February 2025, Serco launched the Defence Advanced Research Projects Agency’s (DARPA) prototype vessel, the USX-1 Defiant. This uncrewed surface vessel (USV) is designed for a series of upcoming trials that aim to deliver a cost-effective USV capability to the US Navy. Not only does the USV perform 90% reliability at sea for a year, it is also capable of autonomous refuelling. [source]

6 Conclusion 

Overall, the US employs a sophisticated, multi-domain approach to ocean surveillance. Not only does the Navy utilise modern capabilities across the public and private sectors, it also successfully integrates methods across land, sea, air, and space. Rooted in the Cold War efforts to counter Soviet submarine threat with systems like SOSUS and the first OSIS and NOSS satellites, US ocean surveillance continues to evolve. Whether land-based data processing facilities, high-performance uncrewed vessels at sea, or ISR aircraft in the sky, ongoing research and modernisation ensure the US maintains its capabilities in a dynamic maritime environment. This integrated network is critical for maintaining strategic deterrence and national security. Ocean surveillance therefore remains a vital asset in preserving maritime awareness and stability.