Crewless Craft on Steady Course

July 2007
By Maryann Lawlor
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The unmanned sea surface
vehicle–high tow force (USSV-HTF), one of the unmanned surface vehicles being developed at the Carderock Division Detachment, Naval Surface Warfare Center, takes part in an operation off the east coast of the United States.
Designers take on maritime operational environment challenges.

Unmanned aerial vehicles have become such an integral part of missions that it is difficult to remember a time when the U.S. military relied solely on manned aircraft. As the U.S. Navy prepares to launch into a similar brave new world where crewless platforms propel warfighters out of harm’s way, the service faces challenges beyond the technical hurdles. Some issues can be resolved by industry; others will require a worldwide national-level consensus that will change the maritime domain with ramifications not seen since the dawn of modern shipbuilding.

Unmanned surface vehicles (USVs) will affect future military and homeland security operations as powerfully as unmanned aerial vehicles (UAVs) have influenced modern military missions, Willard Sokol III predicts. He is the branch head for combatant craft naval architecture at the Carderock Division Detachment, Naval Surface Warfare Center in Norfolk, Virginia, the organization responsible for designing the Navy’s USVs. Many of the same issues must be resolved before any type of unmanned vehicle becomes an ingredient in the military mix; however, operational environments shape the design process, and the wild blue yonder makes it easier for UAVs to take to the air than the deep blue does for USVs to take to the seas. In some cases, being earthbound is advantageous; in others, it is like dragging an anchor.

Despite unique challenges, USVs resemble UAVs in several ways. Some unmanned craft are operated by remote control, whereas others have a scripted capability. The former may feature rudimentary automatic capabilities such as assessing and reporting systems; the latter use a global positioning system to traverse from one point to another and can be programmed to change course. A subsequent level of autonomy, called preprogrammed, includes vessels encoded to follow a specific path but can change course based on input from onboard sensors.

The USVs currently being developed are likely to be controlled using multiple methods, Sokol says. When a craft is docking, for example, it would be controlled remotely; for simple missions, a scripted capability could be employed. In terms of total autonomy, the Navy generally will not use a craft until it is at technology readiness level 6 or 7, he adds.

Challenges in designing USVs are different yet equal in nature to those faced in UAV development, Sokol contends. While aircraft designers address the issue of air traffic, air space management already is basically in place—even privately owned airplanes must emit a signal that designates their location. This is not the case in the maritime environment, he notes. Transmission of identity and location are purely voluntary for sea craft, so ships must maintain a safe distance not only from land—a requirement they obviously share with aircraft—but also from floating and stationary objects in their path. This is one area where sensors are aiding navigation system development, Sokol says.

The first wave of Navy USVs will support the littoral combat ship (LCS). The remote minehunting system, also known as the remote minehunting vehicle, already has been fielded on the service’s fast frigates and will be installed on the LCS. The Navy also is designing and building an unmanned sea surface vehicle (see page 50) that can be used for mine influence warfare. These vehicles will conduct minesweeping missions. The LCS also will carry out antisubmarine warfare missions by employing a system that is being developed by General Dynamics Robotic Systems, Sokol reveals.

For several years, the Navy has been experimenting with how USVs can provide force protection by performing anti-terrorism missions, Sokol allows. In policing or patrolling situations, the service has demonstrated that USVs equipped with cameras can evaluate a situation before personnel deploy. This surveillance has been taking place at military bases both in the United States and overseas. “For the most part, it’s never been anything that’s been specifically indoctrinated and widely done, but it has been done. The military has been looking into using it in other ways as well, and it’s had some successes,” he states.

Although the Navy has been exploring these uses for USVs, development and deployment of the vehicles are tied primarily to LCS delivery and deployment schedules. When littoral combat ships begin operations, the USV and its operators must be ready to go as well. This is likely to take place within the next couple of years, he says.

Designing the USV poses several challenges in certain areas, Sokol admits. “We’re bringing a critical mission capability to the fleet for the first time. We’re doing something that hasn’t been done before. We’re not doing a modification 1 repeat project. We’re dealing with all kinds of growing pains as well as using new technology.

The USSV-HTF is designed to carry large payloads and to tow a variety of sensors.
“We’re talking doctrine as well, not just their specific uses and engineering of system integration. Obviously, the vehicles are being carried and deployed by the LCS, so we’re talking about doctrine of use. What’s the right level of system redundancies? What kind of fail-safes do we need? Those are the types of things that we’re cutting our teeth on,” Sokol relates.

And the nontechnical issues that must be resolved extend beyond doctrine. For example, Sokol points out that training may be one of the more difficult aspects of fielding the USVs. “There’s not a rate or a type of sailor out there today that’s specifically qualified for USVs—not one that you can say should automatically know how to do this. It’s new equipment,” he offers.

Communications methods and bandwidth constraints also set USVs apart from UAVs in design and deployment. A UAV’s altitude increases the distance of line-of-sight communications—not typically the situation a USV will find itself in when communicating, Sokol quips. As a result, the distance a USV can operate from what he calls “the mother ship” may be limited by line-of-sight communications capabilities.

 “We’re also limited in the amount of available bandwidth and what communications gear we can use. The available bandwidth we have to use just to keep a single vehicle on mission can be very limiting,” Sokol adds. But in this case, limitations may be the mother of invention. “These all push us to develop, mature and have more complete autonomy,” he says.

And although information tampering and theft concern UAV developers, these hurdles present even greater challenges for USV designers. “It’s not like an air vehicle. The adversary’s not going to jump from one air vehicle to another and just take it over. For a USV, the enemy could,” Sokol notes. Consequently, communications links must be secured so an adversary cannot take over the USV, and if the enemy does embark on a USV, the information onboard must be secured in some way.

Industry can help solve some of these distinct problems, but the solutions are not likely to come right off the shelf, Sokol maintains. As with UAVs, weight and center of gravity issues must be managed to ensure that the equipment operates correctly. In addition, heating and cooling requirements for electronic equipment must be addressed, and communications technologies must be able to withstand heavy seas and sea mist. “For the most part, we do get the benefit of what rolls out of the [U.S.] Army as well as the other military services, but they’re not always specific to our needs,” he allows.

Sensors and the information they collect and provide are essential but are a double-edged sword, Sokol notes. To ensure reliability and to boost confidence in the abilities of the craft, the Navy wants to have as many sensors as possible on a craft. Redundant verification of the obstacles a craft encounters increases the likelihood that sailors will trust the information delivered to a ship. “We don’t have a lot of operational experience in throwing these vessels over the side of a ship and knowing that they’re going to be fine, that they’re programming is perfect and that they’re going to be able to handle every situation they’re going to come up against,” Sokol notes.

But while it is data—and a lot of it—that will boost confidence in the USVs, this requirement in itself multiplies the bandwidth challenges. The preferable capability would be the ability to process the information onboard the vehicle and then send the oversight operators only the results.

“What we’re talking about is literally sensor integration from the standpoint not just that the sensors can pass information back and forth but that the information that comes in from each of the sensors can be resolved to a single object. Now, instead of sending a camera image, a radar image and, say, a third sensor’s data all the way back to the ship, the only message that the USV sends to the ship is ‘contact made, one mile straight ahead,’ and that’s all that the operator needs to know,” Sokol relates. This capability is still in the developmental stage, and universities are working on the algorithms, he adds.

Late last year, the Naval Surface Warfare Center contracted with Spatial Integrated Systems, Rockville, Maryland, to develop a multipurpose sensor system that includes a state-of-the-art three-dimensional imaging system integrated with intelligent agent technology. This capability will enable autonomous operations in a specified area. With this system onboard, the USV will make routine operational decisions and capture, record and process information that even humans cannot detect.

As development continues, this capability will support autonomy, he states. Once the data can be collected, resolved and collapsed to the bit of needed information, the vehicle will be able to make decisions autonomously, and operators will merely monitor a vehicle’s activity.

This step toward autonomy presents an entirely new set of challenges that must be resolved. For example, when a USV can identify a particular ship sailing into the Chesapeake Bay and determine that this type of vessel would have to travel one of two channels, it would use this information to independently choose a route to avoid a collision. Autonomous capabilities such as this raise questions about the rules of the road uniformly followed by sailors today. “You can see where all this information and all these various contacts will lead to navigating and following rules of the road. Eventually, there’s going to have to be law changes about all of this,” Sokol says.

Currently, the Navy primarily is using USVs in locations where it is in charge of the maritime area. It coordinates scheduling and testing with the U.S. Coast Guard and issues commands concerning radio traffic. But once USVs begin to practice scanning-ship drills, in which they scrutinize vessels to determine whether they are carrying contraband, they will have to operate in waters alongside commercial and pleasure craft. “We have to get the technology to a high enough level that there’s confidence in letting the machines go out there by themselves and confidence in the rules of the road and laws that are associated with what results. For example, who’s responsible if that unmanned boat runs into a ship? Now, we’re creating a new class of vehicle that will have to have doctrine and law that goes along with that for it to be around the public,” Sokol explains.

The Navy has not yet developed a craft that it would put into the water and turn its back on, Sokol allows, but it is working toward a vehicle that can do as much as possible autonomously. “We would tell it that if it encounters some object, it should replan itself to go around it. We can do that. The hard part still tends to be coming up with sensors that can detect and classify objects in all environments,” he states. “The greater that ability is, the fewer sailors we’ll need to oversee and make decisions for the vehicles. It’s really hard, from my perspective, to bring it down any lower than that.”

Web Resources
Naval Surface Warfare Center, Carderock Division:
Naval Surface Warfare Center Detachment Norfolk,Combatant Craft Department:
General Dynamics littoral combat ship program:
Lockheed Martin Corporation littoral combat ship:
Spatial Integrated Systems:


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