Efforts Under Way to Harden Unpiloted Aircraft for Contested Airspace

By their own admission, troops tasked with flying drones in the current conflicts have been spoiled. They often use local runways in Afghanistan and Iraq and enjoy complete freedom in the skies.

But what happens when the services want to fly their unmanned aerial vehicles inside a hostile nation that has the air defenses to deter them? Military leaders are beginning to wonder how Predators, Reapers, Hunters, Shadows and the rest will perform in unfriendly skies.

The NATO bombing of the former Yugoslavia in 1999 lasted two months. During that time, just two U.S. fighter jets were shot down. But allied forces lost about 50 unmanned aircraft in the skirmishes, including 15 drones operated by the United States.

Air Force officials are tight-lipped about what attributes future remotely piloted vehicles would need to increase their chances of survival. “We cannot discuss our operations capability and cannot speculate on future operations,” said Capt. Jennifer S. Ferrau, a spokesperson at Air Combat Command.

But comments made by leaders at recent conferences and roundtables indicate that they are working on the issue behind the scenes.

“We’re thinking about the next war, thinking about the next fight, thinking about the next campaign,” said Air Force Col. Dean Bushey, deputy director of the Joint Unmanned Aircraft Systems Center of Excellence. “We’ve fought in a very permissive environment where there are no enemy attacks against our unmanned aircraft … It would be foolish for us to imagine that we could continue to fly unmanned systems in an environment that is not only friendly but is not GPS-denied, that is not communications-denied.”

The military must continue to develop systems that are hardened against GPS-denied environments, situations where communications are disabled and against aerial and ground threats, Bushey said.

U.S. remotely piloted vehicles are “very” susceptible to electronic jamming, Bushey said. “It would be misrepresentative of me to say we are hardened against electronic warfare,” he said. Insurgents in Iraq and Afghanistan have used inexpensive software programs to intercept video feeds from U.S. drones.

Most systems, but not all, are programmed to fly to a home base when communications go down. The vehicles have computers on board that will find automated flight plans if they don’t hear from their operators. “Sometimes that flight plan is to continue with your mission,” Bushey said.

When NATO began its recent operations in Libya, military leaders didn’t send Predators right away. The Libyans have SA-24 missiles that can be launched from vehicles or off the shoulder.

“That’s one reason that has been given that they weren’t there from day one,” said Keven Gambold, operations director of Unmanned Experts, an international UAS consulting firm. “Because it was a denied aerial environment and [Predators] are straight-winged, slow and not designed with any low observability.”

Two Air Force fighter pilots who formed a folk-rock band called Dos Gringos wrote a song called “Predator Eulogy.” In it, they sing that shooting down the drones is as easy as “clubbing baby seals.”

Gambold and other experts said that this is a common misconception.

“In many respects, they aren’t that easy to see or kill,” Gambold said. He pointed to Operation Southern Watch, which monitored Iraqi airspace between the first Gulf War and second invasion in 2003. Predators were used as bait to stir up Iraqi fighters and air defenses. Surface-to-air missiles eventually brought down two of the drones and an Iraqi fighter jet shot down a third, but it didn’t come that easy to the enemy, Gambold said.

Aging first-generation Predators were used again as lures to expose Iraqi air defenses during the second Iraq invasion. “At the start of a war, you want to know where everything is, so these things are perfect,” Gambold said. “You don’t risk the pilot while you stir up the defenses. And they’re persistent, so they hang out for two days picking up exactly what the battlefield commander needs.”

In the future, most unmanned aircraft probably will have to come equipped with some sort of self-defense system, Gambold said. It makes little sense to design low-observable aircraft with no radar warning capability, he said. But not everyone agrees.

Gambold helped brainstorm a design of a future UAS cockpit, where pilots in remote locations sit while flying the aircraft. During a discussion on what functions the different screens would perform, he suggested one be dedicated to a missile warning receiver. “No one seemed to agree,” he said. But things are changing and the focus has shifted to “the things you are missing that you could use in the next conflict,” Gambold added. The missile warning system is one of those things, he said.

It would be challenging for today’s unmanned aircraft to operate in more contested airspace, said Chris Ames, business development director at General Atomics Aeronautical Systems, creator of the Predator and its variants. The platform has about 950,000 flight hours, flies at speeds up to 125 knots and at heights up to 25,000 feet. The aircraft was designed for a benign environment, Ames said, “but we realized that as the threat spectrum increases, there’s a need for greater survivability.”

The second incarnation of the Predator brought increased speed and the ability to fly at higher altitudes. The third variation, called the Avenger, is even faster.

The Avenger is a “pure jet aircraft” that first flew in 2009, Ames said. It has a maximum speed of 400 knots and can fly at 50,000 feet. The new aircraft features a reduced heat signature and a new shape that allow it to avoid detection. Its payload capacity is such that it could be equipped with a missile warning receiver if a customer so desired.

“I don’t know that stealth is the right word,” Ames said. “Survivability is a better term.” The latter can refer to characteristics from speed and shape to special coating and electronic warfare attack systems. But the cost of the aircraft increases dramatically with the addition of these features, he said.

“Changes and additions to future unmanned aircraft systems must be balanced against the anticipated threat and concepts supporting the UAS mission,” Ames said. “That approach recognizes the fact that UAS survivability requirements escalate procurement costs. The elegance is defining the threat and the employment concept so as to prevent runaway costs.”

Ames uses the manned F-22 fighter jet as an example. It is one of the stealthiest aircraft around, but it also cost $150 million per unit in fiscal year 2009, according to Air Force budget documents.

“You can’t buy a fleet of those,” Ames said. “You’d break the piggy bank.”

Ames envisions unmanned aircraft that will be equipped with flexible electronic countermeasure and attack systems, along with directed energy and kinetic weapon capabilities.

The recent mission to monitor Osama bin Laden’s compound in Pakistan may have provided a glimpse of the future in the use of the RQ-170 Sentinel, an ultra-stealthy drone developed by Lockheed Martin. The aircraft is designed to go undetected by radar and surveillance systems. Unlike the Predator with its separate wings and tail, the Sentinel features a bat shape more closely resembling other common stealth aircraft.

The military is not just concerned about improving its own unmanned fleet, but it also has been working on ways to counter adversary drones. More than 50 nations today have unmanned aircraft and could employ them against the United States and its remotely piloted vehicles during a conflict. The Pentagon has been holding events such as “Black Dart” and “Blue Knight” to see what technology industry has to offer and to test it against adversaries’ unmanned aircraft. This year’s Black Dart event will take place in August at Point Mugu, Calif. Previous experiments have focused on detecting UAS and using directed energy to defeat them.
Changes are also happening in the schoolhouse, said Col. Grant Webb, training chief at the Joint UAS Center of Excellence. More of an emphasis is being put on situations that don’t necessarily reflect current conflicts.

“We have multiple basing options, multiple runways all over the place that we are able to use in Iraq and Afghanistan,” Webb said. “What if you don’t have runways? What do you do?”

Army aviators who recently returned from theater mostly have reported positive experiences. Speaking at a recent conference, Sgt. 1st Class Kelly C. Boehning said that his unit was lucky enough to find an airfield that once was used by the Iraqi Air Force. It came with everything they needed and more, including a hard runway and a communications tower. But other units have been kicked off airfields and were forced to use crumbling facilities.

Army UAS operators are taught that they need an area the size of a soccer field to launch and land their Shadow unmanned aircraft. Without readymade facilities, they said they would have to block off streets to create landing strips and haul dirt from one area to another to build a runway.

“We can stage our unmanned systems pretty much anywhere we want, whether it’s littoral, sea-based or land-based,” Bushey said. “As we move these unmanned systems to other environments like the European theater, the South American theater or the African theater, basing options become very important.”                       

Topics: Robotics, Unmanned Air Vehicles