Air Force takes steps toward 'smart' tanker: new technology could lead to changes in tactics and operational concepts.

The Air Force expects to have a fleet of "smart" tankers ready to fly by year's end. It could take much longer, however, to figure out how to best take advantage of the new technology and how to integrate it into operational scenarios.

In an effort to facilitate "digital conversations" between aircraft operating in a battle zone, the Air Force will equip refueling tankers with antennas and radios that effectively turn the tanker into a communications node. Because they fly above 30,000 feet, the tankers could become the "high ground" for radio transmissions.

An airborne network of smart tankers dramatically would increase the reach of tactical communications by allowing users of different data links and radio frequencies to relay information through the tanker, where a so-called gateway-manager computer would translate the messages to make them accessible to air, land and sea forces.

The notion of a smart tanker emerged in the late 1990s, its legacy being a secret "black" program called Warrior Gateway. The concept has since been promoted by the Air Force Chief of Staff Gen. John Jumper. He views tankers as ideal communications relays, because they fly at high altitudes and area constant presence in any theater of operations.

A smart tanker "expands our communications from line-of-sight to beyond-line-of-sight," said Bruce Stockdale, a technical advisor to the Air Force.

As part of a $30 million program called roll-on beyond line-of-sight enhancement, or ROBE, the Air Force will wire 40 KC-135 tankers and install satellite antennas on the aircraft, so they can become data link nodes. The radios and gateway computers will be placed on roll-on pallets, rather than become permanent fixtures in the airplane. The Air Force will buy 20 pallets, to be used on any of the 40 tankers, wherever they are needed.

The first ROBE-equipped aircraft will be delivered this summer. The plan is to produce seven per month, and complete the entire run by December.

The prime contractor is Modern Technologies Corp. ARINC is responsible for the tanker modifications, and Northrop Grumman Information Technology supplies the ROBE pallets.

"The tankers are always up there flying. So why not use them to help with our communications?" said Air Force Capt. Stephen Thompson, program manager at the Electronic Systems Center.

The ROBE program, however, only provides the initial basic capability to make a KC-135 into a smart tanker. "This is not what a smart tanker will be, but it's a step in the right direction," Thompson said.

Another way to view ROBE is as a "gap-filler" that the Air Force can deploy fairly quickly, rather than wait for more advanced communications relays--such as Global Hawk UAVs and Milstar satellites--to be produced.

On each of the 40 smart tankers will be three antennas: one is for GPS navigation and satellite communications. Two are for the Link 16 joint tactical information distribution (JTIDS) radio.

The roll-on pallet weighs about 140 pounds. It has four metal boxes that contain the AN/ARC-210 satcom radio, the JTIDS, the gateway manager (a laptop PC), a display, a keyboard and associated cabling.

There is no dedicated operator aboard the tanker to run the communications equipment. With crews already stretched thin, the Air Force did not want ROBE to create additional work. Once installed, up and running, it's left alone during flight. In the future, Thompson said, the Air Force will upgrade the system with a remote-control capability, so it can be manipulated from a ground station. The ground operators will be able to filter the data moving through the network, keeping it from becoming overloaded with unneeded information.

The smart tanker program is not just about technology, but also about subtle changes in the culture of tanker crews, said Ed Riley, business development manager at Northrop Grumman. "At the beginning, the crew's reaction was 'don't bother us with this new stuff,'" Riley said. "Over time, they have become more amenable, as they see the utility of the system, such as being able to track the tankers, the airplanes who need gas and how much gas they need.

"This is the first time that the tanker has been able to enter the Link 16 network," said Riley. In the absence of Link 16, the tankers rely on an AWACS air-traffic controller to direct them to the fighters that need gas. "Studies have shown that tankers are 10 percent more efficient just by knowing where everyone is at," said Riley.

Future Upgrades

It is still unclear what the future of the program holds, after the 40 tankers and 20 pallets are delivered. Upgrades are possible, but none has been funded, Thompson said. Improvements could range from adding more radios--such as the Army's situational awareness data link (EPLRS)--to making the system interoperable with the Navy's Link 11 and Link 22 networks.

Communications relay and gateway systems like ROBE eventually all must become compliant with the so-called Mil-Standard 3011, known as joint range extension application protocol. That would allow a commander at the Pentagon, for instance, to keep an eye on the air war via Link 16, as well as to monitor the ground picture.

The ultimate smart tanker would have many more capabilities onboard than just communications relays, Thompson explained. Advanced sensors could turn the smart tanker into an ISR (intelligence, surveillance and reconnaissance) platform, that would contribute to the collection of battlefield information. "That is the true vision," Thompson said.

Stockdale noted that the smart tanker's mission would not overlap with AWACS functions.

"The AWACS do not have the ability to send their radar information beyond line of sight. This is where ROBE becomes a specific enabler," he said. ROBE allows the information to reach wherever commanders are executing the air war.

An industry source who closely follows the smart tanker program said that the Air Force has a "con-ops challenge," referring to the concept of operations, for the smart tanker. "It will take a period of time to evolve," he said. "Not everything can be done on a tanker. Some capabilities are so specific that you can't put them on rankers."

Once the Air Force begins to integrate sensors on the tankers, these could take over some of the work now performed by the Rivet Joint ISR aircraft, the industry source said. It also would make sense for the tankers to have built-in communications packages, rather than roll-on pallets.

A modern tanker, such as a Boeing 767, would provide a better platform for new sensors and communications equipment than the aging KC-135, said the source. "New technology can be applied to old tankers but it would be costly.... It makes more sense to do it with new aircraft, which can better meet the power demands and can fly at 47,000 feet."

Another concern for the Air Force is how to manage the flow of information when airplanes are networked.

"The good news is that everyone shares data. The bad news is that everyone shares data," he joked. "When everyone is infusing [expletive] into the system, you can effectively jam yourself."

The industry expert also questioned the wisdom of expanding the Link 16 network, given that the L-band spectrum--used for air-traffic navigation--already is overcrowded.

Safety also becomes an issue when tankers serve as communications relays. During aerial refueling, the tanker typically does not emit any radio signals, to avoid detection. JTIDS emits lots of energy, so it would have to operate on standby mode every time the tanker refuels an airplane.

Interoperability With Navy

At press time, ROBE was being tested at the U.S. Joint Interoperability Testing Center, said Stockdale, the technical advisor to the Air Force. "Anything that is going to communicate with Link 16 has to go through the JITC," he noted.

The program also received a special waiver from the Defense Department, under a policy designed to keep the services from buying new radios that are not compliant with the Joint Tactical Radio System. "For the ROBE system, we had to get a JTRS waiver," said Stockdale. "That provides a transition plan to migrate to JTRS when it becomes available."

In the long term, the ROBE technology also could find its way into Navy programs, said Riley. Specifically, Northrop Grumman is seeking to interest the Navy in using ROBE-like systems for the broad-area maritime surveillance project--a network of P-3 reconnaissance aircraft and long-endurance UAVs.

The Navy, meanwhile, has been engaged in its own pursuits of roll-on communications and sensor systems for the C-130J aircraft, under a program called Hairy Buffalo-II.

The Hairy Buffalo is a modified NP-3 aircraft used to test C4ISR systems. In a February demonstration, the Hairy Buffalo served as a C4I node for three different battlefield data links: Free Wave, VRC-99 (a networking radio used by the Marine Corps) and the TCDL (tactical common data link). The Naval Air Systems Command said that the Hairy Buffalo architecture could be repackaged to fit a standard military shelter onboard a ship, or be airborne on a C-130.

Hairy Buffalo-II will be a C-130J test aircraft with a roll-on sensor pallet designed in make the C-130J both an ISR platform and an airborne control station for UAVs, possibly for homeland security and Coast Guard applications, said the program manager, Navy Lt. Cmdr. Anthony S. Vivona.

NAVAIR may fund a demonstration for a KC-130J tanker, effectively giving the Navy its own smart ranker, Vivona said. The KC-130J, however, has not yet been certified as a ranker. Hairy Buffalo-II could fly as early as September 2003, said Vivona.

A C-130, noted one expert, would be limited as a smart tanker, because it can only fly at 18,000 feet. Generally, he said, battlefield communications relays are more effective at higher altitudes.