Unmanned aircraft get all the attention nowadays, but it is beneath the waves where robots are making a splash.
From detecting and clearing underwater mines to reconnaissance and mapping the ocean floors, unmanned underwater vehicles (UUVs) are becoming increasingly prominent.
In late October, Secretary of the Navy Ray Mabus announced that a squadron of large displacement unmanned underwater vehicles (LDUUV) will be stood up by 2020.
"These systems are affordable and rapidly deployable worldwide," Mabus said. "They've already been operational and served as critical enablers and game-changers for minehunting missions, such as those that will be conducted aboard the LCS [littoral combat ship]."
While the ocean depths are murky, the attraction of unmanned vehicles for undersea operations is not. Like their robotic counterparts in the air, on land and on the ocean surface, underwater craft are great for dull, dirty and dangerous tasks. They can search for and clear mines while their operators remain safely at a distance, map the ocean floor for monotonous mile after mile, or conduct surveillance of ships and harbors. A 2009 RAND Corp. study lays out a litany of possible UUV uses, including quick strikes from underwater craft quietly positioned close to their targets, anti-submarine warfare and cyber warfare by accessing underwater communications links.
Naval Sea Systems Command (NAVSEA) has several UUV projects underway, according to spokesman Matt Leonard. These include:
- The LDUUV is still under development, but the Navy says it will be considerably larger than 21 inches in diameter, which happens to be the diameter of U.S. submarine torpedo tubes. In addition to the LCS, the LDUUV will be capable of operating from Virginia- and Ohio-class submarines. The intended missions will be more sophisticated than those performed by many current UUVs, including ISR, signals intelligence, anti-submarine warfare, mine countermeasures and strikes on enemy targets. The LDUUV will be long-endurance, reconfigurable and modular, with the ability to operate autonomously in littoral waters. Initial operating capability is scheduled for fiscal 2021, with the Navy planning to acquire 10 vehicles.
- The Knifefish is a big mine-detecting UUV, 22 feet long and weighing 2,200 pounds. Designed to detect bottom, buried and moored mines in cluttered underwater environments, it can be operated from the LCS and other vessels, and each two Knifefish team can be tasked with clandestine Intelligence Preparation of the Operational Environment (IPOE) reconnaissance. Initial operating capability is slated for 2018, with the Navy set to buy 30 systems.
- The MK18 Mod 1 Swordfish is based on the man-portable 7.5-inch diameter Remote Environmental Monitoring Unit System (REMUS) 100 model, which is made by the Woods Hole Oceanographic Institute. The Navy has 27 Mod 1 Swordfish, designed for low-visibility exploration and reconnaissance to support amphibious landings, mine countermeasures detection and hydrographic mapping in the very shallow water zone of 10- to 40-foot depth. The Navy is also developing the MK18 Mod 2 Kingfish, which is slated for operations by the end of fiscal 2016. The Kingfish, which is based on the lightweight 12.75-inch diameter REMUS 600, has greater endurance than the Swordfish and offers an increased area coverage rate through the ATLAS forward-looking sonar. The Navy has 12 Kingfish, rising to 24 by fiscal 2016’s end.
- The Littoral Battlespace Sensing (LBS) system is also based on a REMUS vehicle. The LBS-G is a long-endurance glider that is propelled by changes in buoyancy, and guided by wings and tail fins. It is used to collect oceanographic data. The LBS-AUV is a REMUS 600 used for anti-submarine, mine warfare, naval special warfare and persistent IPOE. Space and Naval Warfare Systems Command has ordered three LBS systems for environmental surveys of ocean, coastal and inshore waters.
- The Persistent Littoral Undersea Surveillance (PLUS) system consists of underwater gliders and REMUS 600 to detect and localize targets in support of anti-submarine warfare operations.
"The UUVs perform as autonomous vessels with long underwater dwell times that carry highly capable sensors," according to NAVSEA's website. "The sea gliders are smaller autonomous vessels that collect the UUV data, and return to the surface to transmit that data to a shore-based collection and processing station. The PLUS system is designed to easily deploy from any ship with a winch and crane and sufficient storage capacity."
In addition, sea gliders operated by the Naval Oceanographic Office (NAVOCEANO) have been mapping the depths since 2012.
NAVOCEANO uses Slocum gliders, developed by Teledyne Webb. Each glider is about 5 feet long, and resembles model airplanes. NAVOCEANO also uses a number of Systems Hosting Autonomous Remote Crafts (SHARCs), variants of the Wave Glider from Liquid Robotics Inc.
The gliders, controlled from Stennis Space Center through the U.S. military's Iridium satellite network, collect data on ocean temperature, salinity, clarity and pressure. The data is used for forecasting oceanographic conditions. Operating at a speed of 0.5 knots, they typically dive to nearly 1000 meters and can operate for up to four months.
"Each glider profile [data collection] costs less than $100, compared to over $10,000 for a ship-based profile," according to a NAVOCEANO fact sheet. "The glider itself costs roughly that of three days of survey ship operations."
But UUVs are not solely an American preserve. Norway's Kongsberg offers several models, such as the HUGIN, which can operate at depths of up to 6,500 yards. Then there is Saab's AUV62-MR mine-reconnaissance UUV, as well as its Double Eagle SAROV mine-detection vehicle, which can operate either under remote control or autonomously.
Meanwhile, Britain and France signed an agreement in March to develop a joint mine countermeasures system that will comprise both an unmanned surface vehicle and an unmanned underwater vehicle. The US $25 million project, which will be undertaken by Thales and BAE, "will involve the design of a Maritime Mine Counter Measures demonstrator, which includes an unmanned surface vehicle with sonar and an unmanned underwater vehicle. It will provide a demonstration of systems and equipment to defeat sea-mines using remotely operated, unmanned marine vehicles and sensors," said a British Ministry of Defense announcement.
Navies are just starting to scratch the surface in terms of UUVs.
"The early part of this decade can be viewed as the beginning of a transitional period," said Jason Stack, program officer for the Ocean Battlespace Sensing Department at the Office of Naval Research. "We now have UUVs that work, work reliably, and are getting affordable enough to buy and field in numbers. Now the emerging technology is focusing on how to employ these systems in increasingly capable and sophisticated ways."
Stack predicts UUVs will become more automated and autonomous. "A significant trend will be for UUVs to achieve a better 'understanding' of their situation and surroundings, be able to have a more rich conversation about this with their human supervisors or counterparts, and to be able to adapt in real-time as appropriate," he said. "This stands in stark contrast to many of today's employments that are essentially constituted by blindly following preprogrammed paths to collect data for later analysis by humans."
Much like the UAV world, where the weaponization of autonomous systems and the development of unmanned combat aircraft have raised concerns about humans in the loop, autonomy is a major issue with underwater craft. Interestingly, Stark speaks of a cycle of trust.
"We see huge variability depending on the specific mission," he said. "However, the trends are the same across all missions — that UUVs and their payloads are becoming more reliable, as reliability increases so does trust, and as trust increases, the responsibility handed to the machine grows."
The evolution of UUV technology promises a future of greatly enhanced — and perhaps even faintly disquieting — capabilities.
"Major improvements in UUV capabilities will be realized as UUVs become able to assess their own performance and proficiency in stride — this is something humans do naturally, and machines typically can't do at all," Stark said.
If UUVs can assess themselves, then they can adapt themselves to changing undersea conditions.
"This will begin to bring the performance of the machine to a level that many people implicitly expect — the machine may not be perfect the first time it tries a new task or old task in a new environment, but it improves noticeably with every experience," Stark said.
