Unmanned aerial vehicles (UAVs) initially gained credence with the U.S. military during the first Gulf War, continued to prove themselves in the Balkans, and finally came into their own as an indispensable asset for air, land, and sea forces at all levels during post-September 11 operations in Afghanistan and Iraq.
They also solidified the foundation for greater research and development of unmanned surface vehicles (USVs) and unmanned underwater vehicles (UUVs), which are substantially behind UAVs in technology development, integration into maritime concepts of operations and acceptance by potential users. But just as UAVs have reduced the number of pilots needed to fly dangerous intelligence, surveillance, and reconnaissance (ISR) missions or penetrate enemy air defenses early in a conflict, so are unmanned maritime systems (UMS) seen as a combination force multiplier and safety enhancement at sea.
That applies to both deep water and littoral (comparatively shallow water regions within a few miles of shore) missions.
“To meet future challenges in littoral and mine warfare, we must understand the operational capabilities resident in technologies such as unmanned vehicles. Furthermore, we must embrace advanced technology and its promises to pace the threat in this very complex world in which we live,” according to Program Executive Officer for Littoral and Mine Warfare (PEO LMW) E. Anne Sandel at the U.S. Naval Sea Systems Command (NAVSEA). “Our single most important job in PEO LMW is to deliver state-of-the-art warfighting capability to the men and women who defend our freedom. Developing technology into operational capability like UMVs is one of the ways we accomplish our mission.
“Unmanned vehicle programs will continue to evolve and play an integral part in tomorrow’s battlespace. I am very excited about how these initiatives are using COTS [commercial off-the-shelf technologies], advanced technology solutions, small business innovation, and open architecture principles to build dependable and affordable unmanned systems. We in PEO LMW are committed to developing UMVs that will engage the enemy at range and ensure tactical advantages in the littoral warfighting environment.”
The U.S. Navy currently has no plans to employ UUVs or USVs for surface warfare operations, although the prospects for UAVs in that arena are growing, and a future role for UUVs and USVs remains open to development. For anti-mine and anti submarine warfare, however, those two platforms increasingly are seen as valuable extensions of existing capabilities.
“We didn’t see a need for them with the surface warfare missions assigned and their requirements,” Capt. Mike Good, NAVSEA’s program manager for Littoral Combat Ship Mission Packages, explained. “For the other areas, there was a very clear operational contribution the unmanned vehicles could make.”
While the Navy is an obvious candidate for UUV and USV applications, the U.S. Army – which has more small boats than the Navy, mostly “brown water” (rivers) and near-shore littoral – also is looking into the new technology. The same is true for the Marine Corps – although their requirements will be met, for the most part, by Navy owned and operated assets – the U.S. Coast Guard, and various other federal investigative and law enforcement agencies.
UUVs and USVs are included in the Militarily Critical Technologies List (MCTL) prepared by the Under Secretary of Defense for Acquisition, Technology and Logistics. The MCTL is described in the report’s executive summary as identifying “technologies crucial to weapons development and has been a key element in evaluating U.S. and worldwide technological capabilities. … The [Militarily Critical Technologies Program] process is a continuous analytical and information-gathering process that refines data and updates existing technology lists to provide thorough and complete technical information. It covers the worldwide technology spectrum and provides a systematic, ongoing assessment and analysis of technologies and determines values and parameters for these technologies.”
USVs and UUVs, according to the report, “may have high-leverage, asymmetric impact on U.S. and allied naval forces.”
“Unmanned maritime vehicles (underwater and surface), both commercial and military, are a growing dimension of marine capability. Technologies for their handling, operations, and mission support (underwater data transmission, vision, and lighting) can improve the military utility of the UUVs in the hands of potential adversaries.” The report also described unmanned maritime vehicles’ potential for direct attack, operations in dangerous waters, and as vehicles to enhance swimmers’ endurance and range.
The report went on to say that technologies listed to “enhance the military utility of UMVs include:
• launch and recovery from host platforms;
• stored energy density;
• capability for autonomous navigation, operations and networking;
• underwater TV cameras and light sources;
• acoustic and fiber optic data retrieval systems; and
• capability for automated target recognition and action.”
Key concerns for UMVs include propulsion and power systems and magnetic and electronic signatures – especially with regard to reducing both noise and visibility to enhance detection avoidance – and communications.
“[Future technology] is a continuing concern of mine in two areas. First is energy, which is key to allowing off-board vehicles to extend the reach of the host platform and allow the flexibility and independence of manned naval platforms to execute their missions without worrying about recovery and refueling,” said Capt. Paul Siegrist, NAVSEA’s program manager for Unmanned Maritime Vehicle Systems.
“Second, while extended length missions and longer endurance require more energy, they also increase levels of autonomy to operate the vehicle for longer periods of time away from the host. In both areas, we maintain our awareness on a lot of developing commercial technologies.”
Both types of platforms can be tethered to their host ship, using that cable to receive controls from a human operator and to return sensor data, or operate autonomously, with no physical connection to the host ship and, typically, following a pre-programmed mission plan, although an acoustic link can be used to enable remote control or modify the mission. A fully autonomous platform can operate at greater ranges and with less potential for detection.
While the launch of either a UUV or USV from a surface ship or submarine is a relatively standard procedure, generally utilizing torpedo launch tubes for UUVs, recovery is far more challenging. For submarines, it requires a homing device to return the UUV to the boat’s launch and recovery system, a device to couple the vehicle to that system and a mechanism to reposition the UUV in the submarine’s torpedo tube. While seemingly less complex an operation for surface ships, which typically use winches or cranes to lift the vehicle from the water, during an ongoing military operation that may need to be done while the host ship is under way to reduce its potential as a stationary target.
Military missions for UUVs include ISR, mine countermeasures (MCM), antisubmarine warfare (ASW), identification and inspection of underwater objects, oceanographic reconnaissance, and underwater mapping. For ISR, ASW, and MCM missions, that also means the ability to detect, assess, avoid or, with more advanced systems, engage potential threats.
“In the area of mine warfare, what the Navy is trying to do is take the sailor out of the minefield. In order to do that, our unmanned vehicle systems provide a tremendous capability,” Siegrist said. “We have man-portable UUVs that provide mine warfare sensing, larger systems [12 3/4-inch realm], and larger onboard systems, such as the Remote Minehunting System, that can extend the detection range significantly.
“In the UUV world, as you increase the volume and size of the vehicle, your range generally is extended. In all cases, we are trying to detect mines at greater distances and take action necessary to neutralize or avoid those mines to accomplish the mission. So it is absolutely an extension of onboard sensors and the field of regard.”
USVs, under the widest definition, have been part of the military arsenal since at least World War II and, as with their aerial counterparts, cover a wider size range than current UUV models, from as small as a miniature torpedo to as large as a Cigarette (a medium-sized speed boat). They can be fitted with explosives for direct-attack missions or with sensor packages for long duration or high-threat environment operations where the use of a manned vessel would be unacceptable (i.e., areas contaminated by nuclear, biological, or chemical agents or where an overt U.S. military presence is prohibited).
“Since unmanned ground vehicles (UGVs) and USVs operate in an essentially two-dimensional world (they cannot fly or submerge), they may share some propulsion and mission system technologies,” the MCTL report noted. “By operating on the water’s surface, a USV can operate on conventional power sources, such as diesel or gas turbine, rather than more exotic and limiting power supplies, such as batteries or fuel cells. A USV could communicate in the three mediums of interest – undersea, air, and space – relaying information from submerged submarines or UUVs to any combination of surface vessels, aircraft, or satellites and vice versa.”
A September 2008 market analysis by Frost & Sullivan forecast that military spending on UAVs and UGVs will be relatively flat through 2016, but both UUVs and USVs will see a steady and consistent year-to-year rise in spending, with the USN dominating the market with a more than 84 percent share. The report also predicts spending on UUVs will be about double that for USVs, but both combined will only total about one-third the expected budget for UGVs, which in turn is dwarfed by UAV expenditures.
Pulling data from both military and industry sources, Frost & Sullivan also predicted the following growth path for UUV/USV mission capabilities through 2030 as follows:
2007-2015: UUVs will be used for reconnaissance, underwater inspection, autonomous mapping, mine neutralization and mine countermeasures; USVs for maritime surveillance and interdiction and ASW;
2015-2025: UUVs will add enhanced oceanography, communications and ISR capabilities; USVs surface warfare and expanded MCM; and
2025-2030: UUVs will expand to ship-deployed communications, submarine tracking and information operations; USVs to armed ASW.
Since September 2007, Good’s Littoral Combat Ship Mission Packages program has delivered the first of each mission package – counter-mine, surface, and antisubmarine warfare – for integration and testing, leading to planned installation on the first of the new class of ships – LCS 1 Freedom – sometime in 2009.
For the mine countermeasures mission, that package included both a mine-sweeping USV and a UUV – the Battlespace Preparation Autonomous Underwater Vehicle (BPAUV).
“For LCS, surface warfare is focused on engaging and defeating small boats; minesweeping and minehunting is a mine countermeasures function, as hunting and defeating subs is an ASW function,” he said. “ASW has two USVs with a variety of sensor payloads; the only work ongoing is not a pure underwater vehicle. There is an effort to adapt the Remote Minehunting Vehicle to do ASW; in this case, they would work together cooperatively, with one towing a medium frequency sonar source [currently in development] and the second a passive hydrophone towed array to receive sonar signals from the other system. That has not yet been fielded.
“In the MCM package, there are two snorkeling unmanned vehicles – the Remote Minehunting Vehicle – which has a sidescan sonar [AQS-20A]. They don’t operate together; we have two in order to have the capacity to cover the water space. Each of those packages incorporates a manned helicopter and an unmanned VTOL [vertical takeoff and landing] UAV. I don’t procure those, but am responsible for integration with them and work very closely with the NAVAIR [Naval Air Systems Command] PMs and their offices in PMA-266 for VTUAV and PMA-299 for the H-60 helicopters.”
The designs of the two different unmanned vehicles designated for MCM and ASW missions are driven by requirements for speed, power and endurance, as well as sea-keeping in the different environments in which they operate. The ASW USV is built by General Dynamics and the MCM USV by Oregon Iron Works, with systems integration on both largely done by the Naval Warfare Center.
“We’re preparing to do end-to-end sensor testing in the water,” Cook added. “Until now, the USV testing has largely been performed by PMS-403 [Unmanned Maritime Vehicle Systems]; as they complete their qualification effort on the USV itself, it will transition to the module level, where my team will take the MCM and ASW USVs and some of the other systems that make up a mission package or set of mission modules and perform an end-to-end test to verify all of the integration requirements have been successfully met. Subsequently, we will test each of the two LCS seaframes.
“At this stage, we’re really locking down configuration so it is very clear exactly what we’re testing. As we identify any issues, we’ll look at how to resolve those. But so far, the testing that has been conducted under PMS-403 shows the USVs are maturing very nicely.”
At PMS-403, Siegrist is working to provide UUV and USV platforms across a range of naval warfare areas. While his office is not directly involved with UAVs or UGVs, they keep a close eye on developments on those platforms because some elements – such as sensors, communications, power – may be applicable across the various regimes, as also is the case between UUVs and USVs.
“Unmanned maritime vehicles are in various stages of integration into different platforms and operational forces,” he said. “We have both UUVs and USVs supporting surface ships, especially the Littoral Combat Ship. At this point, those are primarily engineering development models that will give us lessons learned and allow us to more precisely define requirements and proceed with formal acquisitions in the future.
“For submarine-based UUVs, we recently decided to more aggressively pursue large diameter systems. Within the context of the Navy’s 2004 UUV Master Plan, there are four classes of vehicles: Small man-portable, lightweight [12 3/4 inches in diameter], heavyweight [21 inches], and large [anything larger than 36 inches]. We had been concentrating on 21-inch, but now have turned to large. The previous systems used torpedo tubes for ocean interface, but going with larger vehicles will allow incorporation onto SSGNs [converted Ohio-class cruise missile submarines] and their larger payload tubes, as well as the larger bow tubes incorporated into the Flight 3 Virginia-class submarine.”
There also are studies under way into the technological feasibility of weaponizing UUVs, but any acquisition program for direct attack platforms is considered to be several years away.
“All current systems are autonomous, not tethered, although the degree of autonomy varies from fairly complex to simple to operator-monitored systems,” Siegrist said. “The degree of autonomy really varies with the mission of the vehicle. It is relatively complex when you are operating underwater, out of communication for a long time, less so when you are near the surface and can send back frequent reports. But freeing your operators from continuous monitoring also has benefits; it just depends on the vehicle and its mission.
“The No. 1 mission for UUVs – ISR – remains valid, but we’re also looking at MCM, ASW, inspection and identification – which would be helpful in harbor security – payload delivery in support of forces ashore, time critical strike, and information operations. For USVs, mine warfare and ASW are the priorities, but maritime security is an area of interest. We do have a couple of vehicles we are looking to develop in that area, specifically smaller vehicles for basic maritime security functions. Surface warfare and special ops support also are possibilities, as is interdiction support.”
Longer term, as maritime systems evolve to the extent UAVs already have, their application may expand even beyond what was predicted in the Frost & Sullivan report, including acting as permanently deployed extensions of a submarine’s traditional sensors or operating in tandem or in swarms.
“No reason you couldn’t use a USV to support sub operations, although the nature of a USV would be more complex with regard to launching and retrieving. But if an unmanned vehicle is out there, a submarine certainly could leverage information it is providing,” Siegrist said. “In reality, what unmanned vehicles do is extend the field of regard and influence for any of our naval platforms.
“Integrating unmanned capability into some networked system would be clearly advantageous in some scenarios. While some preliminary work has been conducted, in terms of basic science and technology of a UUV and USV or multiple UMVs working together, at this point it is an area of investigation rather than implementation.”
At the Association for Unmanned Vehicle Systems International’s (AUVSI) Unmanned Systems Program Review 2009 in February, Navy officials termed the growing introduction of unmanned systems a paradigm shift for naval operations. Their impact, AUVSI members were told, ranges from the ongoing war on terrorism to the Navy’s role in battling drug smuggling at sea to anti-piracy missions and whatever new conflicts may arise in the future.
Rear Adm. Mark W. Kenny, director of the new Navy Irregular Warfare Office (stood up in July 2008), told the conference the problem for the Navy is balancing growing budget constraints with a need to more quickly develop and adapt unmanned technology to meet both current and emerging threats. For now, he added, that means surface rather than submarine launch because the former requires less complex launch systems needing less development time and money.
At the same time, the Navy expects UMVs to actually reduce both costs and the need to use valuable manned assets – including SEAL teams, which have had to meet increasing demands from commanders and politicians in recent years. That is one of the reasons behind the new emphasis on large diameter UUVs, which can be outfitted with more sensors and expand from mine countermeasures to littoral ISR, such as near-shore signals intelligence.
“Ideally, we could have a series of them to cover ports or hotbeds of activity and they collate that [UUV data] on the ship,” Kenny said. “What we’re doing is responding to needs from the front.”
Although evolving quickly, UUVs and USVs are still in their infancy in naval operations, not only by the United States, but across the world. But just as happened with UAVs in the past two decades, the number and variety of unmanned maritime systems and their missions are expected to grow rapidly in the decade to come.
“This is an area of emerging capability for the Navy, one in which there is tremendous potential to assist and augment the capabilities of our manned platforms across all areas – submarine, surface, and air,” Siegrist said. “And an area in which we will continue to put forward the best capability possible to assist our sailors in executing their missions.”