Unmanned Surface Vessles
Robot warships are sailing in
Byline: Ted Hooton / London
The past few decades have seen electronics make radical changes in almost every aspect of human endeavour – including the way naval operations are conducted. Indeed the changes are as revolutionary as those in the equivalent period of the late 19th and early 20th Centuries, but one of the most intriguing must be the emergence of the robot warship.
As electronic components shrink in size and swell in processing power almost to infinity, warships have received more accurate and faster-responding sensors, the data processed by command systems and fed to missiles and torpedoes which have become more sophisticated and more lethal. This trend has also raised the prospect that the navy of the future will include substantial numbers of Unmanned Surface Vessels (USV) replacing the conventional warship in a variety of roles just as Unmanned Aerial Vehicles (UAV) play an increasing role in operations against Al Queda and the Taliban in Afghanistan and the Middle East.
This is not science fiction; three Asian navies operate or have operated USVs and the US Navy is steadily introducing them into active service. USVs have been tested since the Second World War and the biggest problem has been one of control – which meant they were largely confined to acting as moving targets, but in the late 1970s this began to change.
With naval mine sensors and control systems becoming increasingly sophisticated the traditional method of neutralising them, by sending manned ships through suspected minefields became ever more hazardous. In the early 1970s the Chinese developed the 47-ton Futi (Type 312) class remotely controlled USV to carry out this task. With conventional hull forms they are controlled by radio from shore up to 2.7 nautical miles (5.7 kilometres) away and carry out sweeps against influence (magnetic and acoustic) mines.
In the early 1980s both the West Germans and the Swedes separately adopted a similar approach; the former using the Seehund drones, which are miniature (95 ton) diesel-powered ships carrying out mechanical sweep Troika operations. These were originally in three-boat teams controlled from a manned mine counter-measures vessel although in practice the Troika could include a fourth drone. Sweden adopted a 20-ton catamaran, to reduce signatures, for influence sweeping as the SAM (Self-propelled Acoustic Magnetic) and this has also been sold to Japan. In the 1990s Australia acquired three glass reinforced plastic catamaran drones from Hamil Haven and these have operated ahead of the auxiliary minesweepers HMAS Bandicoot and Wallaroo, although the fate of the USVs is uncertain as both ships are to be paid off in 2013.
The Hamil USVs have a Global Positioning System (GPS) package which provides accurate navigation and in combination with inertial navigation systems and improved processing these help to make possible the development of autonomous guidance systems for the latest generation of semi-autonomous USVs. The new generation of vessels are capable of carrying out patrols in a predetermined sector without human input but human monitoring is maintained to identify matters of concern and to pursue and, if necessary, to neutralise them. They also have the advantages of reduced life cycle costs and can benefit from commercial USV activity to provide economies of scale.
The earliest models have often been based upon rigid inflatable boats (RIB) because they are light but rugged platforms with deep V planning hulls providing stability even in rough weather making them extremely manoeuvrable platforms. One of the earliest has been the Rafael Protector, based upon a 9-meter RIB, whose water jets give a top speed of 50 knots. The USV has a navigation radar, GPS and an inertial navigation system as well as a Toplite electro-optical surveillance and day/night targeting system is linked to a mini-Typhoon stabilised 12.7mm machinegun.
Controlled by line-of-sight communications from ship or shore the Protector is capable of eight hour missions. It uses Rafael’s Lightlink jam resistant communication technology, to send secure digital video and telemetry to the command centre through the downlink channel and the uplink is used to transmit command data with communication maintained even in severe jamming conditions.
The Protector was designed for patrolling in hazardous environments such as hostile coasts or for engaging potential suicide groups in boats. The human monitor can give instructions to a target boat’s crew through a loudspeaker allowing the USV to provide a first line of defence for personnel and manned ships. Protector was revealed in 2003 and the following year two were purchased by Singapore and deployed in March 2005 from the dock landing platform (LPD) RSS Resolution in anti-piracy duties off the Horn of Africa. At least one was acquired by Sri Lanka for inshore patrols, specifically in areas where Tamil Tiger suicide boats were operating during the insurgency which ended in 2011.
Protector was offered to the US Navy as part of the Littoral Combat Ship (LCS) programme although interest began in the 1990 and was initially for a hydrographic vessel based upon jet-ski platforms. This led to the Owl and with modified low profile hull, a side scan sonar and electro-optic sensor this was used in the Gulf as Owl Mk II, which also formed the basis for the Unmanned Harbour Security Vehicle (UHSV). As a result of an advanced demonstrator programme the Spartan was developed based upon a 7 metre RIBs with 2 tonne payload and some were used for multiple roles in Iraq after 2003, with plans for an 11-metre version.
In July 2007 the US Navy published a USV master plan envisaging four kinds of USV; a small one for use by special forces, a 7-metre Harbor vessel against surface threats and mines, a Snorkler class semi-submersible for mine counter-measures and an 11-metre Fleet class with similar roles to the Harbor but with anti-submarine and electronic warfare roles added. It did not consider the development of a fully autonomous USV feasible in the near future, although autonomous functions including piloting and obstacle avoidance can be added making the vessel a force multiplier. However, it was recognised that with most USVs, being only 2-15 metres long with a displacement of 1.5-10 tonnes, should be confined to harbour protection, reconnaissance and coastal patrol roles. For more advanced roles, such as mine counter measures and anti-submarine warfare, a larger platform with greater stability and the ability to carry a larger payload as well as to tow large sensors is essential.
The master plan is now being implemented in the LCS as part of that multi-role vessel’s mission modules and the US Navy plans to base some of these ships in Singapore as well as its usual bases. The Snorkler is a key part of the mine warfare modular in the form of the diesel-powered AN/WLD-1 semi-submergible Remote Minehunting System (RMS) with AN/AQS-20A towed minehunting sonar which it tows at up to 10 knots and it is used in the anti-submarine module with the Remote Towed Active Source (RTAS), a multiband transducer with a remote towed array multi-function sonar. A Fleet-type USV, with a 7.7 tonne displacement and 2.25 tonne payload, will meet influence mine threats towing the Unmanned Surface Sweep System (USSS) while two will be available to meet anti-submarine threats with dipping, multi-static active and ULITE ultra-lightweight towed array sonars.
In Anti-Submarine Warfare (ASW) modules the two USVs can operate as a team; one will operate the ULITE for long range detection while the other has the dipping or multi-static array for shorter range detection and tracking. General Dynamics Robotics are providing these USVs which have a top speed of 35 knots and are capable of operating continuously for more than 24 hours.
In a separate development in November 2011 the Program Executive Office for Littoral Combat Ships delivered three Modular Unmanned Surface Craft Littoral (MUSCL) X type USVs to the U.S. Navy’s Riverine Group One for tedious and repetitive surveillance tasks. They will be used for real-time monitoring of suspicious vessels, personnel, and activity along waterways, shorelines, and under bridges and piers.
Between July 2011 and February 2012 the US Navy has conducted a series of experiments exploring the capabilities of USVs, the last with non-lethal weapons for maritime security and force protection operations. Operating in autonomous and semi-autonomous modes the USVs employed a directional acoustic hailer, eye-dazzling laser and stun grenades whose use was carefully-orchestrated to respond to a set of threatening behaviour of intruder vessels.
During Exercise ‘Trident Warrior 2011’, the USVs’ ability to react autonomously to vessels travelling in protected waterways were tested and validated. The USV had a rotating laser to survey the waters environment around it and provide information about approaching boats so that it could take appropriate action. This year’s ‘Trident Warrior’ in June will be multi-phased and integrated with major joint and multi-national exercises in the West Coast.
In the short term most USV development is focused upon commercial applications but a number of naval systems are under development. The Swedish company Kockums is involved in the Piraya project with four USVs capable of operating independently, in a miniature squadron or in conjunction with land- or sea-based systems for surveillance and harbour security. In Italy Calzoni are developing the U-Ranger, originally developed to meet a mine counter-measures requirement and now adopted for multi-mission roles with manual, semi-autonomous and autonomous modes. The last involves the craft following a pre-planned track but it will be capable of performing planned manoeuvres independently thanks to obstacle avoidance and target identification features
Israel’s Elbit have developed the 11-metre RIB-based Silver Marlin with 12.7mm machinegun and electro-optical packages for security and surveillance missions. In the US a similar sized platform is part of AAI’s Common Unmanned Surface Vessel (CUSV), a catamaran-design capable of mine counter-measures and anti-submarine warfare mission as well as communications relay, intelligence, surveillance and reconnaissance, anti-surface warfare and UAS/UUV launch and recovery of UAVs and Unmanned Underwater Vehicles (UUV). Similar roles are envisaged for the Zyvex Marine Piranha 1.37-metre, 3.6 tonne commercial design made from a lightweight carbon-nanotube enhanced composite material called Arovex, which is claimed to allow the craft to weigh significantly less than any other USV. The Piranha can carry a 6.8 tonne payload and has a range of 2,500 nautical miles (4,600 kilometres.
Yet despite the advances USVs have limited applications either in surveillance/reconnaissance or in support of manned ships and certainly they require monitoring either from ships or shore bases. There is little doubt, however, that they can act as force-multipliers within conventional task groups especially for patrol and mine counter-measures roles, the ASW role must be regarded with some scepticism as this form of warfare requires high sensor-operator skills and the expertise to deploy weapons at the appropriate time. However, they can help extend ASW sensor coverage.
The question for navies is how to integrate USVs into operations; should they operate from conventional warships or should they operate from what might be called ‘robot carriers’. Indeed France, Italy and the United Kingdom are all considering the concept of a high-speed mother ship initially for the mine counter-measures support role with large spaces to store and to maintain robot systems as well as the command and deployment facilities not only for USVs but also for UUVs and UAVs.
Rolls-Royce, who are the world’s leading and largest supplier of deck machinery and handling systems, are addressing the problems of operating USVs through their subsidiary Rolls-Royce Naval Marine Canada. The company believes future surface combatants will need to operate numbers of USVs and have a number of solutions, often based upon technology developed for the offshore oil industry.
With many USVs based upon RIBs the obvious launch/recovery solution is the stern ramp, which is already integrated into many new patrol vessels which use RIBs to deploy inspection teams and can be used in 8-metres seas. Deck-mounted handling systems in mission bays already exist in the offshore oil industry to handle underwater vehicles and could be adapted for USVs while the company produces automatic sea fastening systems and containerised mission packages for commercial applications.
The company produces automatic deploying and towing systems for sensors which can be deployed in USVs, it has developed a crane-based refuelling system which permits automatic refuelling at sea of USV as well as handling systems which can move a USV to or from a stern ramp. It is supplying a crane-based USV deploying system which lifts the craft out of the mission bay, across the side and into the water. The company have declined to identify the customer or application but the evidence suggests it is for Singapore’s Formidable class frigates.
A possible signpost to the future is an ambitious US USV programme launched with Defense Advanced Research Projects Agency (DARPA) funding in October 2010 is the four-stage programme to produce the ASW Continuous Trail Unmanned Vessel (ACTUV) which is to be the first unmanned naval vessel designed for independent long-endurance deployment in regional theatres and even world-wide.
The programme has three primary objectives, of which the first is to design, build, and demonstrate a technology demonstrator in which no person steps aboard at any time during operations. The programme will demonstrate the technical viability of an autonomous USV with limited remote supervisory control and then integrate it with a sensor suite capable of tracking quiet modern diesel electric submarines.
The ACTUV will be able to detect submarines within a nautical mile (1.852 kilometres) and to track them navigating autonomously around the world in all kinds of ocean conditions. It will also be able to employ its sensor suite autonomously and carry out appropriate tactics based on target behaviour and environmental conditions and it will be capable of long deployments without human maintenance or repair.
Several first-phase initial study contracts, each worth US$2 million, have been issued with recipients including Northrop Grumman Undersea Systems and QinetiQ North America Technology Solutions Group. In December 2011 DARPA sought responses to Phases 2-4 by the end of February 2012; Phase 2 will involve integrated hardware-in-the-loop testing, Phase 3 will fund construction of an integrated prototype vessel and initial sea trials, and Phase 4 will involve mission-oriented sea trials. Phases 2-3 will cover 36 months and Phase 4 up to 18 months. The vessel will have a service life of up to 15 years and is to be deployed three times a year and have a range of 3,300 nautical mile (6,200 kilometres).
As human beings have a distrust of machines operating without supervision, DARPA plans to give the ACTUV at least minimal supervisory command and control. Shore bases will monitor performance intermittently and provide outline mission objectives through beyond line-of-sight communications links while the vessel itself will have the autonomous navigation and anti collision features now regarded as essential for USVs. The command and control system will be based upon commercial-off-the-shelf (COTS) and customised sensors to provide the situational awareness it needs to respond to target behaviour.
How viable the ACTUV concept will be as a future surface combatant remains to be seen but it does appear that in the next couple of decades USVs will become a feature of the world’s navies. In part this is driven by the increasing cost of conventional platforms and the difficulties of manning them making robot solutions more cost effective as well as creating more platforms. But the problem with full robot vessels is the daunting prospect of a naval equivalent of Arnold Schwarzenneger’s Terminator with a shoot-on-sight policy. Where the happy medium will lie remains to be seen but admirals will clearly be living in interesting times, to paraphrase the Chinese curse.