F-35 radaren - Avionics

F-35 AESA: The Most Advanced Jet’s Biggest Antenna

By Nick Zazulia | September 4, 2018
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AESA, electronically scanned array, F-35, JSF, Lightning II, radar

AN/APG-81 AESA Radar (Northrop Grumman)

 

Active electronically scanned arrays (AESA) date back more than 20 years, but the F-35’s Northrop Grumman-built AN-APG-81 AESA is unlike any of its predecessors.

The AESA is "the biggest antenna on any airplane, so it gathers the most data,” said Dan Dixon, Northrop Grumman’s director of F-35 development planning. The electronically scanned nature of the AESA allows it to quickly scan any direction, compared to a mechanically scanned radar, whose range is constrained by the direction it is facing and how quickly its motors can turn it.

The AESA can also harvest information from all over the electromagnetic spectrum, so there is a lot coming in. Digesting all that data requires a lot of processing power, which is where technological advancement in recent years has been key. On a jet like the F-35, the system needs to be able to correlate what it’s receiving with other electronic warfare systems and radar information to provide a holistic picture.

Dixon said the feedback that Northrop gets from pilots about the fused information package they ultimately receive is positive, and the military is pleased with the ripple effect of increased situational awareness for the entire fleet. He said, however, that there’s more work to do on that front, determining who gets what information through multifunction advanced datalink and Link 16.

“It’s basically the internet of the sky for all U.S. and coalition partners,” Dixon said. “You would have had to do that with your voice in the past … It’s a mix of who gets what, but I have the opportunity to choose the richness of the data that gets exchanged. I think that’s probably the game-changer at that point.”

Dixon said that the Northrop team “is spiraling capability every week” in a way that “commercial folk would find compelling.” He said that software and apps are being updated on a weekly basis, and that the platform is agile in a way belied by stories of decade-long processes for follow-on modernization to complete a goal.

He said the testing and verification process and a desire by operators to have a stable baseline for a couple of years to unify training prevents the major updates from happening as fast as they could from a developmental standpoint.

“Even though behind the scenes you’re brewing up additional capabilities for the next drop,” Dixon said, “about every two years seems to be what the warfighter is requesting. It’s perceived stability and operational performance.”

The biggest challenge in the past for Northrop and a major focus going forward, as with the JSF in general, is on affordability.

“Joint Program Office is under a lot of pressure to work affordability initiatives in, and we get it. That’s all recompete-driven, so the enterprise gets it, too,” Dixon said. “Nobody’s above reproach. We treat it that way. We’re always looking for affordability features; We’ve come down 30-40% since we started making the radar.

"…We’ve spent as much time finding ways to produce our system more affordably as we do in finding technical upgrades, which is important for the enterprise. We’ve all adjusted, I think, and there are other competitors out there who sure would like to be a part of a 3,000-aircraft buy, no matter when you cut in.”