The Future of Maritime Warfare: Unmanned Undersea Vehicles (UUVs)

August 21, 2012 - via Maritime Security Challenges 2012

Royal Roads University, the Asia Pacific Center for Security Studies, and Maritime Forces Pacific will be holding the biennial Maritime Security Challenges conference in Victoria BC from October 1-3, 2012. One of the conference panel discussions will focus on maritime applications of unmanned vehicles.  This article by Craig Graham explores several different uses for unmanned undersea vehicles (UUVs) in maritime security operations.

There has been significant coverage in the media surrounding US unmanned aerial vehicle (UAV) strikes in Afghanistan, Pakistan and elsewhere; however, it is probably less well known that navies around the world are adopting similar robotic technology for maritime use. Officially known as unmanned undersea vehicles (UUVs), these high-tech submersibles are currently being assigned to mine countermeasure (MCM) operations, naval intelligence, surveillance, and reconnaissance (ISR) roles, and anti-submarine warfare (ASW) missions. And while compared to UAVs, UUV technology is still in its relative infancy, the use of UUVs, notably in places like the Strait of Hormuz and off the coast of Iraq, has ensured the safety of personnel operating in hostile maritime environments, and has changed the way in which maritime security operations are conducted.

There are generally two kinds of UUVs used in military operations: autonomous undersea vehicles (AUVs) and remotely operated undersea vehicles (ROVs). Although distinctions between the two are becoming increasingly blurred through rapid advances in technology, an AUV can typically be described as a submersible vessel that maintains some degree of autonomy from human control, while an ROV is either mostly or completely controlled by humans via a cable that connects the ROV to a remote control, usually on a surface vessel.

In early July 2012, the United States Navy (USN) responded to Iran’s threats to use warships and mines to close the strategic Strait of Hormuz – through which around 40 percent of the world’s energy travels – by deploying dozens of ROVs to the Persian Gulf. The small semi-autonomous ROVs, called SeaFox C, are made by German naval systems manufacturer Atlas Elektronik. Each ROV, which sells for roughly USD $100,000, is equipped with an integrated homing sonar device that autonomously locates mines previously found by minesweeping surface vessels. Once these mines are located by the SeaFox, the ordnance is identified by a video camera and then destroyed under the instruction of the human operator with a “large calibre shaped charge,” which also eliminates the ROV. Given the relatively small size of the SeaFox at just 43 kilograms, the vessels can be launched from surface ships, small craft, and even helicopters, and can locate and destroy enemy mines within minutes of deployment.

Another anti-mine UUV currently employed by the USN is the Remote Environmental Monitoring Unit System (REMUS). This lightweight, torpedo-shaped AUV uses sonar to patrol shallow waters in search of anti-ship mines. After the vehicle is recovered, sonar data is reviewed and any discovered ordnance is removed by divers. The USN estimates that around 50 countries have a total of over 250,000 mines in their possession. In order to reduce the risk to humans in sub-sea mine disposal, UUVs are being used more frequently. In 2003, US forces in Iraq used REMUS UUVs to locate mines in the approach lanes to the port of Umm Qasr.

UUVs are also being developed for use in ISR operations, which will reduce the risk to manned intelligence-gathering vessels. The United States Office of Naval Research (ONR) is currently working alongside Science Applications International Corporation (SAIC) on an AUV that deploys and controls several tiny UUVs in hostile waters in a collaborative intelligence-gathering effort. Typically, manned vessels are used to deploy and recover UUVs in unfriendly waters, but this new AUV acts as the host. It carries, deploys, and recovers smaller UUVs and then downloads the collected data from them. The ONR’s challenge is to produce an unmanned vehicle that is difficult to detect and completely autonomous in order to further improve ISR missions.

An AUV that could be well suited for ISR operations is the sea glider, a small, energy efficient, winged AUV. This vessel uses a unique form of propulsion in which a small pump fills and empties a chamber, changing the vehicle’s buoyancy and allowing it to ascend and descend as a means of moving forward. While most gliders can only move at speeds of up to half a knot, these vessels have extremely low energy demands which allow them to stay at sea for months at a time. Although gliders currently lack the situational awareness needed to avoid detection by adversaries or from getting tangled in fishing nets, their endurance and ability to operate stealthily due to a lack of noise-producing engines makes them ideal candidates for ISR missions. Gliders can also be deployed by submarines to detect and locate a passing ship without the vessel realizing it is being tracked. The USN is considering working with California-based company Liquid Robotics to develop an AUV called the Wave Glider for ISR-type missions.

UUVs are also being considered for ASW missions to support nuclear-powered attack submarines (SSNs) that typically carry out ASW operations. This development could allow UUVs to replace SSNs in ASW tracking missions so that SSNs are able to perform more critical duties. Although very little has been revealed about these UUVs, the Talisman A – currently under development by British defence company BAE Systems – is being designed specifically for ASW missions. The USN’s UUV Master Plan 2004 suggests that an ASW-specific UUV, such as the Talisman A, should be equipped with a passive sonar device, which, unlike active sonar, only receives acoustic signals instead of sending and receiving them. This would allow UUVs to track a submarine by following the sounds that it makes without sending its own signals, thus avoiding detection. The Talisman A would also likely be fitted with what is known as a non-traditional tracker, or electromagnetic sensor, which can be used for initial detection of a submarine or to maintain tracking of the vessel. Furthermore, along with advanced communications systems, the Talisman A may need a short-range high frequency, low-probability of intercept sonar to avoid obstructions while tracking submarines.

UUVs are currently being used by the USN in ASW training exercises as well as being used in preparation for future submarine tracking operations. UUVs, such as the reusable MK-30 Acoustic Target and the MK-39 Mod 2 Expendable Mobile ASW Training Target (EMATT), are being used by the USN to simulate enemy submarines during ASW training. According to the USN Fact File website, the MK-30 works by mimicking the “dynamics, acoustics, and magnetic signature” of an enemy submarine, and acts as a “target for ASW sensors and torpedoes to detect, classify, track, and pursue in a realistic training environment.” The MK-39 will even avoid torpedo attacks by moving autonomously, making it an excellent alternative to a real submarine during training exercises. The EMATT can operate at speeds of up to eight knots, and can last for up to four hours submerged. The UUV can also move realistically, responding to active sonar noise or by using artificial intelligence to respond similar to a real, human-controlled submarine.

Global maritime security is rapidly evolving as UUV technological development continues. While mines are already being dispatched by ROVs, maritime intelligence operations will likely be supported by silent AUVs in the near future. And although USN ASW training currently uses UUVs, future ASW operations may be bolstered by stealthy robotic submarines, identifying and tracking enemy submersibles to provide distance between the host vessel and hostiles. Furthermore, though this robotic maritime technology is still in the beginning stages of growth, UUVs have proven to be a safe alternative to personnel operating in dangerous environments.

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Author:Craig Graham

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