Raytheon and the US Navy (USN) are looking to increase the jamming capability of the Boeing EA-18G Growler by also using the electronic attack aircraft’s APG-79 active electronically scanned array (AESA) radar.
They have discussed updates that would give the Raytheon-made radar the ability to jam enemy transmissions. Such a capability would be in addition to the Growler’s payload of current and future jamming pods, including the USN’s trio of next-generation jammers.
“The navy is looking to understand how to employ [AESA radar] best, along with the next-gen jammers,” says Eric Ditmars, vice-president of secure sensor solutions at Raytheon Intelligence & Space.
Ditmars’ comment, made in an interview with FlightGlobal last October, offered a rare glimpse into the top-secret world of electronic warfare, which is central to an increasingly heated arms race between the USA and near-peer adversaries China and Russia.
“We are already seeing races in airborne electronic warfare, [in terms of] power and range. This is part of the response to that,” says JJ Gertler, senior associate with the Center for Strategic and International Studies.
Electronic warfare, which includes radar jamming, has been used by the USN and US Air Force in past wars to temporarily blind, frustrate and confuse opponents.
INCREASED THREAT
The possibility of using the EA-18G’s AESA radar for jamming points to the navy’s hunger for electronic measures that can help counter the increasing number of advanced surface-to-air missile systems and combat aircraft being fielded by Beijing and Moscow.
Additional jamming capabilities might allow Growlers to attack targets more precisely, or from greater stand-off ranges, say electronic warfare experts. New capabilities might also allow them to hit more targets simultaneously and across a wider swath of battlefield.
The Growler can already carry up to five ALQ-99 Tactical Jamming Systems – two under each wing and one under the fuselage centreline. The USN plans to replace the Cold War-era technology with a trio of next-generation advanced jammers, respectively designed to operate in low-, mid- and high-band frequencies.
The service awarded Raytheon a contract last July to start producing the ALQ-249 Next Generation Jammer Mid-Band (NGJ-MB). That system, scheduled to reach initial operational capability by autumn 2023, is intended for offensive electronic attacks against air-defence and communications systems using mid-band radio frequencies.
“This is the first time we know of [that] anybody has tried to do both technologies on the same airplane,” says Gertler, referring to combining AESA jamming capabilities with purpose-built jammers.
Unlike older radar systems using mechanically pivoting arrays, AESA radars electronically steer individual antennae, allowing the system to transmit in different directions – and at different frequencies – simultaneously. It also allows for the rapid and simultaneous detection of multiple threats.
The mid-band ALQ-249 also employs AESA technology. “AESAs are very steerable. You can aim directly at a target,” says Gertler.
Radar jamming could be useful when the Growler’s dedicated pods are already employed. The system could allow electronic warfare officers to quickly shut down specific threats – such as enemy surveillance aircraft and a radar-guided missile – on other frequencies, he adds.
AESA-based jamming is not new. For example, Northrop Grumman’s APG-81 AESA radar, fielded on the Lockheed Martin F-35 stealth fighter, can jam some surface-to-air missile systems.
“While the idea of using AESA in this application has been around for a while, processing improvements make it a viable capability,” says Brad Martin, a retired captain and surface warfare officer with the USN, who now works for think tank RAND Corporation.
AESA radars can operate passively, “listening” for adversary radar transmissions. This can allow defending aircraft to detect adversaries without being detected themselves. That listening ability, as well as computing power to make sense of what is being “heard”, is useful for jamming.
“Using AESA as a jammer allows rapid processing of threat information across a broad spectrum, and then rapid response with a jamming beam that’s tailored to the specific detected threat,” says Martin. For example, a Growler protecting an aircraft carrier battle group could use its AESA to jam radar-guided anti-ship missiles, he says.
But AESA jamming has limitations. The nose-mounted radar systems are not designed for electronic warfare and can jam only targets ahead of the aircraft. Also, while jamming, the radars cannot perform their primary mission: searching for enemy aircraft.
“I’m envisioning a scenario where you have several Growlers up. Some of them are using their radars to detect aircraft. Their buddies are using their radars for jamming,” says Gertler. “It ends up being a team operation.”
Co-ordinating the APG-79 AESA with the Growler’s purpose-built jamming pods is tricky, because additional radio waves from the radar can interfere with other aircraft systems, such as radar warning receivers, says Ditmars.
“You just have to make sure you have the right software, which we are quite capable of doing, to make sure that everything is working in concert,” he says. “You have to decide on your mission: When do you want to employ the jammer? When do you want to employ the radar?”
Adding AESA jamming capability would be done as a software update through the EA-18G’s rolling block upgrade programme, says Ditmars.
The APG-79 has the biggest antenna on the EA-18G, larger even than the ALQ-99, he says. The array’s size is “on par” with the incoming NGJ-MB.
“In a contested environment, you are not sure how many jammers are going to be employed on you or how many different targets you will have – so the more options you have, the better,” Ditmars says.
AMPLE POWER
When in jamming mode, the APG-79 would not compete for electricity with the Growler’s purpose-built jamming pods, he says. That is because the pods receive power from ram air turbine-generators that harness the jet’s forward airspeed.
“Everybody is trying to reach out farther and farther, to establish their zones around their countries and around their units,” says Gertler. “The more power you have to be able to burn through the electronic interference, and the larger an area you can defend, the more of an advantage you have.”
Raytheon did not respond to questions about specific applications for AESA jamming, and the USN also declined to comment. The service notes that it frequently discusses different uses for various technologies, but says such discussions do not mean a programme of record is imminent.
The USN is usually reluctant to talk about jamming, notes Gertler.
“[Electronic warfare] is one of the least talked about aspects of military aviation because it’s such a sensitive technology. Hard numbers are very difficult to come by,” he says. “[But] the concept of using both ends of the Growler for jamming makes a tremendous amount of sense.”
