Alert to danger

Radar warning receivers help pilots make faster decisions

Surface-to-air missiles travel at mach speeds and can hit a target in seconds.

To a pilot, those seconds are precious. The earlier the warning, the more time a pilot has to make a critical decision: divert or engage.

This is where radar warning receivers, or RWRs, come in. They detect anti-aircraft threats and alert pilots, giving them  more time to take defensive measures.

“If you’re unaware of a threat, you’ll keep doing what you’re doing, possibly putting yourself in a deadly situation,” said U.S. Air Force Maj. Douglas Ferro, 118th Airlift Squadron, 103rd Airlift Wing, who pilots cargo aircraft. “Radar warning receivers dictate tactics to degrade the adversary’s opportunity to engage us.”

Any type of aircraft – manned or unmanned, strike or cargo, tanker or bomber – can become a target.

“The problem today, as opposed to even 20 years ago, is the threats are so much more advanced with extended range and digital processing capabilities of the radar,” said Gene McFalls, a manager at Raytheon Intelligence & Space, a business of Raytheon Technologies, and formerly, an Air Force B-52 electronic warfare officer and director of the Air Force Special Operations Command EW Reprogramming Center. “In the past, you could operate outside the Weapons Engagement Zone and still accomplish the mission, but now that zone has grown exponentially and it puts aircraft like tankers at risk.”

Today’s all-digital RWRs can process significantly more information and pinpoint a threat’s location.

“Cargo guys go into austere environments – areas devastated by natural disaster or an airfield or road in the middle of nowhere,” said McFalls. “The increased sensitivity and accuracy of a digital RWR is going to let them know exactly where the threats are and avoid them.”

Flying C-130s in all Operation Enduring Freedom deployments, Lt. Col. Cade Keenan, 139th Operations Support Squadron, 139th Airlift Wing, knows firsthand that with an RWR, aircraft can go into higher-risk areas.

“Fighters, by virtue of their jobs, have to go into areas where surface-to-air missiles have not been taken down yet,” he said. “Until RWRs, we had to wait until they were taken down. Now, we can go in before that.”

Pilots must also navigate through a wide range of signals in an electromagnetic spectrum crowded with cell phone traffic, long-wave and short-wave radio transmissions and microwave energy. Aircraft systems must be able to tell a pilot which signals are friendly and which are hostile. That's why processing massive amounts of data is so important in an RWR. If it can’t process that information, it gives an unknown signal notification that can potentially confuse pilots.

“If you get a lot of unknowns, then it’s confusing,” said McFalls. “You need more processing to tell you exactly what the threat is, and that’s what an all-digital RWR does.”

Raytheon Technologies’ all-digital RWR, ALR-69A, is outfitting the U.S. Navy MQ-25 and U.S. Air Force tanker and cargo aircraft, and is being tested on the F-16.

“Analog systems get bogged down because they’re just like are a huge vacuum, sucking up everything and trying to figure out what’s what,” said Keenan. “Digital RWRs actually allow us to discriminate between the noise – literal noise and waveforms we’re interested in knowing about.”

The other advantage of an all-digital system: It will be able to adopt new technologies in the future, including cognitive and artificial Intelligence, enabling systems to identify unknown threats in near real-time.

“As air crew, all you want to do is accomplish your mission and get home safely,” said McFalls. “Electronic warfare – radar warning receivers – let us do that.”