Airborne Network Gateway Keeps Warfighters on the Same Wavelength

February 2012
Topics: Combat Service Support, Signal Processing
MITRE engineers helped develop the Battlefield Airborne Communications Node, which links warfighters with their command, even in mountainous terrain.
UAV

When warfighters need to call for air support, contact their command center, or communicate with one another for any other reason, it's critical that they have a clear signal and reliable connection. The risk of being cut off can determine a mission's success or failure as well as a soldier's life or death.

Staying connected, however, is a challenge because personnel in different locations often use different networks. In addition, every communications system has its vulnerabilities. For example, ground-based communication networks become targets, and satellites aren't always within radio line of sight.

A few years ago, Lt. Col. John T. Cheney, who at the time led the Tactical Data Networks requirements branch at Langley Air Force Base in Virginia, proposed the idea of an airborne communications gateway. In response, a small team of MITRE engineers—working with the Electronic Systems Center (ESC) at Hanscom Air Force Base in Massachusetts and staff from Northrop Grumman—collaborated to develop a communications relay that operates from the payload of a high-altitude aircraft.

The relay, known as the Battlefield Airborne Communications Node (its acronym—BACN—is pronounced "bacon") is already generating results in the field, supporting critical tactical data operations by providing communications among joint forces on the ground, in the air, and on the sea.

This new capability moves incoming signals from one waveform/frequency to another as the aircraft flies over an assigned area closing communications links and tying disparate networks together. Closing these gaps enables the sharing of information across the operational theater, often across great distances.

"We have some aircraft that use one radio standard, and other aircraft that use a different standard," explains Dave Dodge, leader for MITRE's Quick Reaction Capability (QRC) Project. "Even though warfighters function in the same theater, they can't always talk directly to each other. BACN was seen as a way to bridge all of them together–providing one network from north to south."

Convoys in Deep Valleys

"Originally, the vision was for BACN to provide a single, tactical data link," says Kevin Fong, deputy project lead for the QRC and MITRE engineering lead of the BACN project. Along the way, however, the Air Force program office directed Northrop Grumman to add multi-mode airborne voice radios to the payload. The addition of voice radio had immediate impact.

"It turns out the most urgent need among military convoys in theater was to maintain contact with one another and with their bases," Fong says. In some areas, the convoys are moving through deep valleys where satellite signals are difficult to maintain.

"At first, the Army built towers with radio transmitters on top of them along the thoroughfares where the convoys went," says Fong. "Terrestrial wire linked the towers. But the problem was defending the ground network. Not only did the convoys become targets for ambushes, the communications system was difficult to protect as well." Satellites provide an alternative, but they're not always in the proper position to aid communications.

Airborne relays like BACN are more nimble and less expensive than a satellite, and the airborne communications relay is also more readily moved into a position where it is required than ground-based gateways. In addition, the encrypted transmissions relayed through BACN can't easily be deciphered by anyone who attempts to intercept them. Most important, BACN ensures a continuous communications link across a broad territory.

A Borrowed WB-57 Canberra

"We started back in 2005, with the concept of a gateway node that could connect or relay for other nodes, then translate and forward information for other users," Fong says. According to Dodge, there were no formal user requirements. "We knew that if a thing like BACN existed, and we proved there was value in it, the users would buy into it," he says.

In 2006, the BACN team brought a prototype to the Joint Expeditionary Force Experiment (JEFX), a military exercise where the Army, Air Force, Marines, and Navy demonstrate experimental projects that are not official programs. For JEFX 2006, Northrop Grumman built a prototype using a borrowed WB-57 Canberra that NASA had converted for high-altitude experiments. The system performance at JEFX made a great impression, stimulating additional funding to continue development. The successes at JEFX 2006 also led to efforts to mature the payload and systems operations, which helped pave the way for its ultimate deployment to theater.

At JEFX 2008, the team demonstrated BACN using a Bombardier BD-700 business jet. This particular aircraft arrived already outfitted with antennas and radar domes for an experimental air surveillance platform and was easily adapted for BACN. After another successful demonstration at JEFX 2008, the team took BACN overseas to provide critical voice bridging, relay, and tactical data networking capabilities.

Dodge notes that warfighters are hesitant to change the systems they use, particularly if change involves incorporating capabilities that haven't been rigorously tested. By deploying BACN in phases, with a promise to turn it off if it caused problems in the network, the Air Force project managers gained the warfighters' trust and BACN proved its worth.

A Real Airborne Network

That initial test aircraft has evolved into a fleet of business jets and unmanned aerial vehicles. The military currently uses this fleet every day for multiple types of missions, connecting tactical edge warfighters to air support operations centers, the combined air and space operations center, and the control and reporting centers.

"BACN is the beginning of a real airborne network," Dodge says. "Eventually, we may deploy lower tier networks or other high-flying interconnected nodes." While the project took three years from concept to first aircraft deployment, Dodge notes that BACN is an example of a project that moved quickly, by military standards.

MITRE helped keep the process moving quickly by focusing the team on mitigating the most critical risks, such as co-site interference, environmental compatibility, and airworthiness certification. MITRE staff performed analyses and simulations, and developed quicker processes, to more rapidly identify solutions with acceptable risks.

"We focused only on the experiment and functionality," says Dodge. "We did what was required by the acquisition regulations, but tailored the project to a minimum possible set of deliverables that was acceptable. If it wasn't required, we didn't do it. We were trying to determine whether this was really worth doing, whether it would benefit the objective. We didn't want to waste effort or the government's money."

In fact, the BACN project, which achieved its mission of providing a means of consistent communication in the theater, led to the establishment of the Air Force Quick Reaction Capability branch. "MITRE, the Air Force, and the contractors worked as a cohesive team," Dodge says. "We agreed to check our badges at the door—whatever it took to get communications in the [soldiers'] hands. And now the warfighter is seeing the benefit of it."

—by Molly Manchenton

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