Active electronically scanned arrays (AESA) may be the key to powering the US military’s super-wideband airborne networks of the future, perhaps with the initial goal of dramatically improving the ability of AESA-equipped tactical fighters to perform real-time surveillance missions.
US industry has noted this potential application for AESA systems scheduled to enter service in December with the US Air Force’s Lockheed Martin/Boeing F-22A Raptor and in 2006 with the US Navy’s Boeing F/A-18E/F Block 2 Super Hornet.
Lockheed and Boeing are understood to have launched separate studies into the potential of AESA sensors as super-high-speed data transmitters. Meanwhile, DirecNet, a new consortium founded by Cubic, says the US Department of Defense has asked it to schedule demonstrations to prove the AESA datalink mode. “Using AESA datalink capability or, potentially, other solutions to even larger pipes is in the initial stages of concept studies and may work their way into the roadmap,” says Kory Mathews, Boeing’s director of growth opportunities for the Super Hornet programme.
The AESA radar’s primary role is to serve as a dual-mode air- and ground-tracking sensor for the F-22 and F/A-18. But the technology also shows promise as a data emitter mainly because it uses the X-band frequency. This region of the spectrum is already compatible with the military’s Common Data Link (CDL) terminals and is ideal for wideband throughput of up to 1Gbit/s. The Northrop Grumman APG-77 AESA aboard the F-22 and the Raytheon APG-79 AESA in production for the F/A-18 will collect and fuse vast amounts of data about the battlefield.
However, offloading this data to others who need it is problematic. Neither the existing Link 16 datalink nor the planned Rockwell Collins tactical targeting network technology (TTNT) waveform appear to offer sufficient bandwidth. The APG-77, for example, would collect data at a rate in excess of 80Mbit/s, while TTNT offers a 2-10Mbit/s bandwidth range, says Gary Nault, a Cubic CDL product manager and a founder of DirecNet. “As soon as they run into that problem, TTNT is not going to do it,” he says. “They have a lot of data they want to get off their sensors.”
AESA’s promise as a datalink also has its challenges. A key concern is that the need to transmit at very high rates across hundreds of miles requires extremely precise aiming for the AESA beam.
STEPHEN TRIMBLE / WASHINGTON DC