AUVSI 2014: US Unmanned Maritime Systems

While war has spurred technologies and concepts of operation for UAS and UGV systems on and over land, the maritime arena has lacked such a sharp goad. Naval systems have generally moved more slowly in accordance with established notions of dull, dirty and dangerous missions.

Thinking is shifting beyond this towards systems that work in teams with humans and manned platforms, according to US Navy (USN) Chief of Naval Research R.Adm. Matthew L Klunder. The goal, he said in a January presentation, is an affordable hybrid manned and unmanned force. The Office of Naval Research (ONR) wants ideas for systems that can ensure access to complex, contested maritime domains, solve problems in logistics and intelligence and provide decision support to commanders, under Anti-Access/Area Denial (A2/AD) conditions with limited communications. Strong themes include greater autonomy and flexible multi-mission platforms that span high-end, moderate and low-end capabilities.

The X-47B Unmanned Combat Air Vehicle (UCAV) conducts touch-and-go maneuvers aboard the aircraft carrier USS Theodore Roosevelt (CVN 71). Theodore Roosevelt is the third carrier to test the tailless, unmanned autonomous aircraft's ability to integrate with carrier environment. (Photo: US Navy /Mass Communication Specialist Seaman Anthony N. Hilkowski)

While the stealthy X-47B UCAV demonstrator achieved significant milestones last summer and the Broad Area Maritime Surveillance Demonstrator (BAMS-D) logged its 10,000th combat hour in January 2014, as part of what began as an experimental deployment in 2009, intended to last just six months; most seaborne efforts are focused more on teams of smaller vehicles rather than on such high-end platforms. The Littoral Combat Ship (LCS) is a major focus of this approach – although the Unmanned Carrier Launched Airborne Surveillance and Strike (UCLASS) system for which the X-47B and the Unmanned Combat Air System Demonstrator (UCAS-D) programme are paving the way could cooperate in strike packages.

Littoral Combat Ship’s (LCS) Unmanned Progression

While the LCS programme has been curtailed at 32 ships (down from 52), the reasons behind the decision are connected with the survivability and firepower of the design rather than the extensive use of unmanned systems (UnSys) in their mission packages, which is a powerful idea with relevance and influence far beyond the programme. The concept of a mother ship operating a diverse mix of manned and unmanned vehicles is establishing itself in thinking about more coastguard-oriented missions, ECA Robotics' SIMBA 455 being a prime example, more of which later.

Increment I of the LCS mine countermeasures package features a combination of manned and unmanned systems, namely Sikorsky's MH-60S helicopter – which can deploy the AQS-20A mine hunting sonar, the Airborne Mine Neutralisation System (AMNS), and the Airborne Laser Mine Detection System (ALMDS) – and Lockheed Martin's unmanned submersible Remote Multi-Mission Vehicle (RMMV), which can also tow the AQS-20. Increment I, says the USN will provide twice the sustained area coverage rate of a current AVENGER-class MCM ship.

Both designs have a helicopter deck and hangar and are capable of launch and recovery of the MH-60R/S helicopter and a tactical UAV.

Plans call for later increments to add more capabilities based on UnSys. Due in FY15, Increment II will bring beach zone mine and obstacle detection in the form of the Northrop Grumman AN/DVS-1 Coastal Battlefield Reconnaissance and Analysis (COBRA) system. COBRA is composed of two airborne payloads, one of which is a stabilised EO pod, carried by an MQ-8B FIRE SCOUT unmanned helicopter. Increment III in FY17 will add the Unmanned Influence Sweep System (UISS) and an upgrade to the ALMDS to bring mine sweeping and near-surface neutralisation capabilities. The UISS consists of an USV and a towed magnetic and acoustic sweep. The ability to detect mines in the surf zone, including buried ones, will come with FY19's Increment IV and the General Dynamics KNIFEFISH autonomous UUV, which is based on Bluefin Robotics' 21in diameter BLUEFIN-21, and an upgrade to COBRA. KNIFEFISH will be equipped with a broadband, low frequency synthetic aperture sonar.

The USN is currently working to document the performance expected of each increment, drawing on Naval Mine Warfare Simulation modelling and insights gained in developmental testing, according to a report by the Congressional Research Service published on 11 March 2014.

SIMBA Supports Multiple Missions

ECA Robotics' SIMBA 455 concept, in a nutshell, is a family of 45, 50, or 55m mother ships with operating ranges up to 5,000nm and endurance of up to 20 days. They can house a suite of on-board sensors and facilities to support a variety of mission-specific AUVs and USVs, the acronym SIMBA being derived from IMagery & BAthymetry System for Hydrographical & Oceanographic Survey. The vessel itself can make simultaneous use of a variety of sensors, such as a side scan sonar, a multi-beam echo sounder and a sub-bottom profiler. It can also deploy towed sonar arrays. Electric propulsion reduces radiated noise, while a degaussing/deperming system minimises its magnetic signature, both critical in MCM operations.
The vessel is also intended to host a menagerie of UUV/AUV, ROV, and USV systems, and is equipped with a hydraulic deck crane and A-frame, both of 5t capacity, an electric launch boom capable of handling 2.5t vehicles, a stern ramp with a 5t winch, a towing winch, and a vehicle maintenance workshop, along with a command and information centre for mission planning and monitoring. Vehicles SIMBA 455 can operate include the 9m, 4.5t INSPECTOR USV, the 5m ALISTER AUV, and the 65kg H 300 ROV.

Stealthy Subsurface Mother Ships

With the growing emphasis on countering anti-access/area denial threats in the Asia Pacific region and elsewhere, the USN has acknowledged the need for a stealthier launch platform for UnSys than any surface vessel can provide. While the obvious answer might be to use a submarine, these will be increasingly scarce, heavily tasked assets into the foreseeable future, hence DARPA's HYDRA underwater mother ship effort. The agency published a Broad Area Announcement (BAA) on 22 August 2014, inviting proposals for the 18-month design and technology demonstration phase of an undersea system that will provide a novel mechanism for insertion of UAVs and UUVs into operational environments.

Launch and Recovery of Manned and Unmanned Boats and UUVs (Photo: US Navy)

“An unmanned technology infrastructure staged below the oceans’ surface could relieve some of that resource strain and expand military capabilities in this increasingly challenging space,” said programme manager Scott Littlefield, commenting on the BAA's release in August. DARPA wants HYDRA to use modular payloads within a standardised enclosure and intends to develop and demonstrate initial “payloads” the mother ship can launch or deploy, while keeping their options open on future examples. DARPA sees HYDRA as a cost-effective way to add undersea capacity that can be tailored to support a variety of special operations and contingency missions.

The programme is divided into five technical areas, the first centred on the modular enclosure, the second and third on the air vehicle and undersea payloads respectively, the fourth on concepts of operation and the fifth on supporting technologies. DARPA wants proposals for an enclosure that will operate for long periods in littoral waters to transport, house and launch various payloads and serve as a “mission truck” that will provided basic services and support. The air vehicle payload that DARPA envisions is a number of individually encapsulated air vehicles within a module that fits into the HYDRA enclosure. For launch, the vehicles would be ejected from the enclosure, float to the surface, launch and perform one or more missions as described in classified and export controlled annexes to the announcement. Proposals should use existing vehicles, modified variants of them or at least maximise the use of existing components to keep costs down.
DARPA sees the undersea payload as a module containing a small number of standard UUVs, the emphasis being less on their missions than on facilities to transport, launch, recover and recharge them – using an air-independent system – and transfer the information they collect to the network.

An example of the kind of supporting technologies DARPA is interested in is efficient means of recharging undersea vehicles.

“By separating capabilities from the platforms that deliver them, HYDRA would enable naval forces to deliver those capabilities much faster and more cost-effectively wherever needed,” Scott Littlefield concluded.

Nearer fruition is the Large Displacement UUV (LDUUV), an effort under the control of the Program Manager for Unmanned Maritime Systems (PMS 406). Like HYDRA it is intended to deploy payloads stealthily in contested water, but LDUUV is to be significantly more mobile. Intended for launch from a variety of platforms including surface ships and shore facilities, projected LDUUV missions include intelligence preparation of the environment, ISR and offensive operations. PMS 406 intends to award an EMD contact during FY 15.

Sub-Chasing Unmanned Surface Vehicles (USV), Autonomous Underwater Vehicles (AUV)

HYDRA is one of several major efforts to advance the state of the art in UnSys for naval missions that DARPA is undertaking. The agency expects to begin testing an operational prototype of the ASW Continuous Trail Unmanned Vessel (ACTUV) at sea in mid-2015. Cued by ASW search assets, which make the initial detection, the USV is intended to track very quiet non-nuclear submarines over long periods, holding them at risk and neutralising the threat they represent to friendly forces. With no constraints imposed by habitability requirements, the design can be optimised to provide “complete propulsive overmatch” against such submarines in a much smaller and less costly vessel – the first of the agency's three primary goals for the programme.

The Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessel (ACTUV) is developing an unmanned vessel optimised to robustly track quiet diesel electric submarines. 

The second is to bring UnSys autonomy to state in which they can deploy independently on missions lasting months and covering thousands of kilometres using what DARPA describes as a “sparse remote supervisory control model.”.This includes compliance with maritime laws and conventions for safe navigation, managing its own systems to maintain operational reliability and interacting autonomously with an intelligent adversary.
Primary goal number three is to demonstrate ACTUV's ability to employ its non-conventional sensor technologies – including multiple active sonars – to establish and maintain “robust continuous track of the quietest submarine targets over their entire operating envelope.”

Phase one refined and validated the system concept, performance measures and risk reduction testing on sensor and autonomy technologies. The programme is now moving through phases two to four in which contractor SAIC is working to design, build and test the USV, which weighs 80t and measures 130ft long and 40ft across its trimaran outriggers, ahead of the planned operational testing.

Sub-Hunting Autonomous Underwater Vehicles (AUV)

The underwater analogue of the ACTUV is the Submarine Hold At Risk (SHARK) UUV, which is intended to work with a network of passive acoustic sensors placed on the deep sea floor known as the Transformational Reliable Acoustic Path System (TRAPS). SHARK and TRAPS are key elements of DARPA's Distributed Agile Submarine Hunting (DASH) programme, SHARK being based on Bluefin Robotics Bluefin 21 AUV and TRAPS a development led by SAIC. Like ACTUV, SHARK would use active sonar to hold contact with a submarine detected by other means. Both successfully came through deep water tests during 2013.

Cooperative Operations

2013 was also an important year for advancing concepts in which multiple UnSys of different types cooperate to hunt submarines, with separate tests carried out by NATO and by US Naval Sea Systems Command (NAVSEA).

During NATO Exercise “Proud Manta 2013” (16 February to 2 March), the organisation's Centre for Maritime Research and Experimentation (CMRE) demonstrated multi-static ASW operations with a pair of OCEAN EXPLORER AUVs, built by Florida Atlantic University, and a Liquid Robotics WAVE GLIDER wave powered USV. With a sonobuoy putting sound in the water, the AUVs towed passive sonar arrays and sent their data to the WAVE GLIDER via acoustic modem. Acting as a comms gateway, the USV sent the information to the NATO research vessel Alliance, which housed the mission control element.
On 24 October, NAVSEA reported completion of the first in-water tests of the Persistent Littoral Undersea Surveillance (PLUS) system, which uses a combination of REMUS 600 long-endurance UUVs and SEA GLIDER buoyancy-driven vehicles, both of which are now available from Kongsberg. The REMUS 600s carry sonar for target detection and acoustic modems to communicate with the gliders that regularly surface to send the data back to the control centre via satellite. Tests are set to continue until early 2015, when the Navy plans to deploy PLUS for operational evaluation overseas.

While human interaction remains important in all these concepts, the technology of machine autonomy is being pushed towards great reductions in personnel requirements in terms of numbers and levels of training, driving the evolution of hybrid human/machine teams that are more effective than purely human ones operating dumb equipment.