By J.R. Wilson
PATUXENT RIVER NAS, Md. - It will have taken nearly four decades, but the U.S. Navy is finally about to enter two years of flight testing of a 21st-century replacement for the carrier-based EA-6B Prowler electronic warfare (EW) aircraft. That replacement-the EA-18G Growler-is itself based on the Navy’s F/A-18 Hornet strike fighter aircraft, which was not yet even in design when the Prowler first entered service in 1971.
The Prowler is scheduled to remain an active part of the Navy air fleet through about 2015, while the Growler is set for initial operational capability (IOC) in 2009.
Even with the EA-6B’s most recent “improved capability” (ICAP III) upgrade, what the Growler brings to U.S. sea-based EW represents the major technological advances of the 1990s and 2000s. In part, that is evident in the extensive use of open architecture “off-the-shelf” hardware and software-based upgradability.
The Growler is based on the recently introduced, greatly upgraded, and larger F/A-18E/F Super Hornet. The Growler, in fact, is four feet larger than the F/A-18E/F in length and wingspan.
“We had a short timeframe from 2009 IOC to a 2012 full operational capability transition to 10 carrier squadrons, so we needed to reduce technological risk to achieve that schedule,” says Greg Drohat, EA-18G deputy program manager and civilian lead in the Naval Air Systems Command (NAVAIR) Program Executive Office (PEO) Tactical Aircraft. NAVAIR is located at Patuxent River Naval Air Station, Md.
“Fiber-optic networks, databuses, mission computers, and so on, are the same as the Lot 30 F/A-18F, which is our take-off point for the first production EA-18G,” Drohat says.
Growler systems integrators are installing what Drohat calls “a fairly mature” Northrop Grumman ALQ-218 ICAP III tactical jamming receiver, legacy Multi-Mission Advanced Tactical Terminal (MATT), and EDO Corp. ALQ-99 low-band tactical jamming system pods. They are also developing the Interference Cancellation System (INCANS) and Communications Countermeasures Set (CCS).
These systems “did have some predecessor systems from which we are leveraging technology,” Drohat says. “Our intent was not to develop new technologies, but to evolve what was available and look to the future for new upgrades. We have a development roadmap beyond Block 1 and 2012, using a quality functional deployment that looks at potential capability upgrades to mature and integrate new technology into the platform.”
INCANS incorporates an active cancellation technology that samples the centerline jamming environment, then cancels it out from the broadcast frequency of the Growler’s UHF radio.
The Advanced Electronic Attack (AEA) mission computer is the electronic attack unit (EAU), a fairly small, single-card computer from Mnemonics Inc. in Melbourne, Fla. The EAU fits in the gun bay, where the F/A-18F currently carries a 20-mm cannon. The EAU interfaces with the aircraft mission computer (AMC) via a Fibre Channel network to control the entire electronic attack system.
A programmable interface unit also is being added to allow integration of the ALQ-99 onto the Growler. It is essentially an analog-to-digital converter to compensate for the Growler and Prowler configuration differences.
“From an architecture standpoint, instead of integrating the EAU system with the AMC from the ‘F,’ we developed a separate mission computer for the AEA suite. Otherwise, there would not have been sufficient room for growth and future system upgrades in the AMC,” Drohat says. “Upgrading from a Type 2 to a Type 3 AMC is a common change for the Super Hornet and Growler. We were bumping up against Type 2 capacity limits, so the Type 3 gives us both processing and growth capacity for the life of the airplane.”
The Growler will also feature the Super Hornet’s new APG-79 Active Electronically Scanned Array (AESA) radar, which enables simultaneous tracking and targeting of multiple air and ground targets. Combined with the ICAP III AN/ALQ-218 EW Receiver Suite, which provides precision passive radar threat detection, identification, precision geolocation and jammer control, the Growler will have unprecedented situational awareness.
“We are extending the architecture that exists on the Super Hornet today to fully integrate the airborne electronic attack suite on the Growler,” explains Kevin Fogarty, EA-18G avionics integration lead at Boeing Integrated Defense Systems in St. Louis. “That includes taking advantage of the Fibre Channel high-speed interface that was introduced into the F/A-18 Block 2 about a year ago to integrate the AESA and new mission computer and now the AEA.
“All our software is high-order language, so there is little risk changing one module would impact the overall functionality of the product,” he says. “The computers are largely COTS and easily integrated and updated. We built the architecture and the hardware with growth in mind.”
While there are no current plans to incorporate the new, faster 1553E enhanced databus into the Block 1 Growler, program officials in the Super Hornet program office are considering the faster databus, and it also is a candidate as a possible future upgrade for both aircraft.
Boeing EA-18G deputy program manager Mike Gibbons says the sum of the parts, even without being individually revolutionary, creates a strikingly evolutionary new capability.
Super Hornet capability
“A modern platform brings a lot of sensors out to the fleet, but what the Growler brings that nobody else does is Super Hornet capability integrated with ICAP III, plus the ability to communicate by voice while jamming. That integration is a definite step up from the EA-6 fleet,” he says. “We will get the Type 3 AMC during flight test and will have that upgrade in production. And the EAU will give us additional processors over and above the Super Hornet.
“So compared to the EA-6B it is replacing, the Growler has definite different capabilities to the fleet AEA mission. The AESA radar is significant, as are the additional weapons stations and carriage capabilities, so they can carry the ALQ-99 pods, HARM (AGM-88 High-Speed Anti-Radiation Missile) and AMRAAM (Advanced Medium-Range Air-to-Air Missile), which is a definite upgrade. The Super Hornet itself gives us tactical maneuvering and speed the EA-6B doesn’t have.”
That advancement also extends to the EA-18G data correlation mechanization (EDCM), a set of algorithms written into the mission computer to integrate multiple sensor inputs and do an updated correlation to provide the aircrew with a more coherent display.
The MATT uploads offboard information, the Link-16 tactical data link provides two-way tactical and intelligence information with the Global Information Grid (GIG), and UHF radios can continue to provide voice links while jamming, thanks to INCANS. That corrects a major problem with the EA-6B, where communications are vulnerable to aircraft’s own jamming systems.
“It may not be that bad because Link-16 has a tremendous amount of inherent protection. The EA-6B is experiencing that now with the ICAP III aircraft, which is the first to have an ALQ-218 receiver and Link-16; version 2 of the ALQ218 will be on the Growler,” says Capt. Steve Kochman, EA-18G deputy program manager and military lead.
“We will have a direct link between our new communications countermeasures set and one of the ALQ-99 transmitters, which is a new linkage. The CCS box also is a great technology transformation as a software programmable box with a tremendous amount of capability.”
The EA-18G’s receiver/jammer architecture also represents a significant departure from the EA-6B, which carries the stand-alone USQ-113 receiver/jammer-essentially two Rockwell Collins AN/ARC-210 multiband, multimode radios.
The Growler uses the software-programmable CCS receiver-a field-programmable-gate-array (FPGA)-based Joint Tactical Radio System (JTRS) derivative built by Raytheon in Fort Wayne, Ind., incorporating off-the-shelf technology into one weapons replaceable assembly (WRA)-and the ALQ-99 as the jammer. The two are integrated into the overall electronic attack system for greater flexibility in programming the receiver set, which can be moded to identify evolving and multiple communications transmissions, both friendly and enemy.
“The 113 was developed in the mid-’80s, using off-the-shelf technology; there have been quantum leaps in technology since that are inherent in this box,” notes Cmdr. Paul Overstreet, NAVAIR’s EA-18G chief engineer. “One of the key benefits of integrating involves going from four to two crewmen and a reduced workload.”
Another advantage for the Growler is its commonality with the F/A-18E/F, which program officials say has a robust interoperability roadmap that has been under development for several years to ensure the E and F models work well with the Navy carrier battle groups and Air Force assets in theater.
Some legacy systems currently in the Growler flight-test models remain concerns to the program office, however. That is especially true of the jamming pods.
“We have had a longstanding problem with traveling wave tubes in some of the older jamming pods and are working on a solid-state amplifier replacement (from Teledyne MEC in Rancho Cordova, Calif.),” Kochman says. “We’re in the midst of a developmental program so we won’t be reliant on those wave tubes, which are hard to produce and difficult to maintain-they have 25 percent yield on a good day. We hope to have the replacement on Block 1.
“Our major goal is a maintainability and reliability improvement, but the potential for cleaner power also is expected to come from it. That generally translates into less interference and fratricide, so we expect to have improvement from that perspective, as well. As we keep having trouble producing and maintaining the traveling wave tubes, we are having difficulty meeting fleet operational requirements, so it is important from that standpoint.”
Current Navy plans call for 90 Growlers, which will be stationed at Whidbey Island Naval Air Station, Wash., home of the EA-6B fleet. That is also expected to be the primary training facility for new Growler crews, probably a mix of pilots and crew switching from the F/A-18 and EA-6B, along with new pilots and backseaters who will begin their careers on the EA-18G. The training system is in concurrent development at Boeing, which is training the flight-test crews at its simulation facility, but will deliver the first dedicated Growler trainers to the Navy at the end of flight-testing.
“During the development period, we brought in both EA-6B and F/A-18 aircrews from the Navy and Marines to participate in the development of the displays and architecture,” Gibbons says. “It is very important to get the input of both aircrews and trainers, so we had more than 300 aircrew providing input into the crew vehicle interface, in addition to dozens who have provided time and thought as part of our formal design advisory process.
“Their ability to make the transition from either of those platforms has been very rapid, which was the intent. We tried to develop the displays and crew vehicle interface to be intuitive; the control system uses a HOTAS (hands on throttle and stick), which allows for the aircrew to very quickly change the modes and displays they are looking at and manipulate them, as you might with a mouse on your desktop computer. It is quickly picked up by the aircrews.”
Gibbons says the Growler already was on the minds of engineers when they began development of the Super Hornet’s all-glass cockpit, enabling them to switch easily from its advanced crew station and larger displays to the Growler’s different, specific mission and operating environment.
That also applies to the Boeing/VSI-built Joint Helmet-Mounted Cueing Systems (JHMCS) from the F/A-18E/F. With flight and targeting information displayed on the helmet visor, pilots are able to simply look at, lock on and attack air-to-air and air-to-ground targets anywhere within their field of view, significantly increasing launch speed, weapon effectiveness and aircraft survivability.
“On a development program such as ours, we’re not trying to invent or mature technologies, but integrate them,” he adds. If you look at the primary technologies that have been critical in allowing us to be as successful as we are in this effort, those would be:
- data correlation, which we have been working at Boeing for years and have improved upon with the EDCM;
- INCANS, which it was important for us to ensure was mature enough before we began the EDCM development; and
- a digital channelized receiver system, which is integral to the ALQ-213.
F/A-18G Growler glossary
AEA - Advanced Electronic Attack
AESA - Active Electronically Scanned Array
AMC - aircraft mission computer
AMRAAM - Advanced Medium-Range Air-to-Air Missile
CCS - Communications Countermeasures Set
COTS - commercial off the shelf
EAU - electronic attack unit
EDCM - EA-18G data correlation mechanization
EW - electronic warfare
GIG - Global Information Grid
HARM - AGM-88 High-Speed Anti-Radiation Missile
HOTAS - hands-on throttle and stick
ICAP III - improved capability upgrade III
INCANS - Interference Cancellation System
IOC - initial operational capability
JHMCS - Joint Helmet-Mounted Cueing Systems
JTRS - Joint Tactical Radio System
MATT - Multi-Mission Advanced Tactical Terminal
NAVAIR - Naval Air Systems Command
PEO - Program Executive Office
WRA - weapons-replaceable assembly