Industry Scan.

'Game-Changing' EO DAS Nears Action on Joint Strike Fighter

As a fifth-generation, multirole fighter, the F-35 Lightning II brings a lot to the table in terms of stealth, lethality and survivability. One "transformational" system that is quietly nearing flight on the aircraft is the Electro-Optical Distributed Aperture System (EO DAS).

Designated AN/AAQ-37, the EO DAS is comprised of six infrared sensors, flush-mounted around the aircraft to afford 360-degree, spherical coverage - in mathematical terms "4 pi steradian." The sensor array will provide the F-35 pilot with missile-warning, situational awareness and navigation FLIR, operating simultaneously, in one package. Integrated via the mission computer, the system will support target detection and identification functions of the aircraft's Electro-Optical Targeting System (EOTS) and AN/APG-81 active electronically scanned array (AESA) radar.

Northrop Grumman Electronic Systems Division is supplying both the EO DAS and AN/APG-81 radar for the F-35, or Joint Strike Fighter (JSF). The company in late June invited Avionics to its facilities in Linthicum, Md., near Baltimore- Washington International Airport, to discuss the status of the two core systems.

With the short takeoff/vertical landing (STOVL) variant of the fighter having just taken wing (see page 11) and with two F-35s now racking up flight hours, much of the discussion focused on the lesser reported EO DAS.

"Most people think of us as the radar company [but] this is the real game-changer for the F-35 that separates it from the F-22 and the F-18," said Dave Bouchard, director of JSF Programs. "The F-22 has a very basic missile launch detection system; this is a significant game-changing capability."

Said Pete Bartos, marketing director for Combat Avionics Systems, "People really don't get what DAS does. It's just one of those unknown, very core pieces of the JSF that, by the way, no other airplane in the world has."

Development of the system started in 2002, based on earlier technology. The program included flights of a F-16 equipped with a DAS sensor in a centerline pod to record data in a dynamic fighter environment. Live missile testing was conducted to collect data and validate models. The first flight of an EO DAS on Northrop Grumman's BAC 1-11 testbed, initially fitted with three sensors, took place in November 2005.

Data collected during flight tests has been used to develop and optimize algorithms that process sensor data - where the real functionality of the system lies, Bouchard said. "In the algorithms, we seamlessly stitch together two or three cameras depending on the field of regard. Our requirement is to have seamlessly stitched, near 20/20 visual acuity," he said. Extremely fast update rates are required to prevent latency of the DAS imagery, which will be projected onto the pilot's helmet-mounted display. "It has to be updated fast enough so the eye can't tell it's a video image as opposed to the real image," he said.

Infrared sensors of the Electro-Optical Distributed Aperture System surround the aircraft with 360-degree protective sphere, providing missile warning, situational awareness and navigation FLIR

Graphic courtesy Northrop Grumman

The Netherlands, a JSF program partner, has contributed to the EO DAS development. Northrop Grumman in 2003 contracted with the country's Organization for Applied Scientific Research, Physics and Electronics Laboratory to provide signal-conditioning algorithms to enhance the clarity of DAS imagery. Thales Cryogenics, of Eindhoven, The Netherlands, is providing cryogenic coolers for the infrared detectors.

At this writing, Northrop Grumman's BAC 1-11, mounted now with a full set of six sensors, had flown more than 100 hours with the EO DAS. The time flown is more impressive, Bartos said, when considering that DAS sensors collect a terabyte per hour of data. That information is archived by the company to check system performance. However, the baseline F-35 has no data storage mechanism, and using the system to track a missile, for example, "will be like taking a sip out of a fire hydrant," he said.

The company had delivered three sets of EO DAS sensors to JSF prime contractor Lockheed Martin for its mission systems integration lab in Fort Worth, for the Cooperative Avionics Test Bed (CATBird) aircraft, and for BF-4, the first F-35 slated to fly with the system. Bouchard said CATBird, a modified Boeing 737, will start flying with mission systems hardware this fall, including the AESA radar. The EO DAS "is about nine months to the right of radar," he said, putting its first flight on CATBird in latter 2009 and on F-35 in 2010.

In addition, Northrop Grumman had been awarded two contracts for Low-Rate Initial Production of the EO DAS - the first for two shipsets of six sensors each; the second for 12 shipsets. The first production delivery is slated for the end of the year.

The executives rolled a video that had been prepared for the Farnborough Airshow with previously unreleased EO DAS imagery. The narrator sings the praises of the system's many capabilities, which include missile warning and launch-site detection, continuous tracking and ID correlation during aerial combat, day and night vision around the aircraft, including through the floor, and high off-boresight target designation.

"In the age of high off-boresight weaponry and highly maneuverable aircraft, hesitation means defeat," intones the narrator. "... With DAS, maneuverability is irrelevant. Instead of mutual kills, the F-35 simply exits the fight, and lets its missiles do the turning." - Bill Carey

Tanker Ruling

The U.S. Government Accountability Office (GAO) sustained Boeing's protest of the KC-X tanker contract award to Northrop Grumman and EADS, likely delaying the priority tanker replacement program and calling into question the ability of the Air Force to manage large procurements.

GAO issued its decision June 18, responding to the March 11 protest filing by Boeing. Finding that the Air Force "had made a number of significant errors that could have affected the outcome" of the tanker competition, the congressional investigative agency recommended the service obtain revised proposals and make a new source selection decision.

The Air Force by law was allowed 60 days to inform GAO of its actions in response to the decision. In a statement, Sue C. Payton, Air Force assistant secretary for acquisition, said, "The Air Force will do everything we can to rapidly move forward so America receives this urgently needed capability. The Air Force will select the best value tanker for our nation's defense, while being good stewards of the taxpayer dollar."

The competition pits Boeing's KC-767 tanker against the KC-45A, a tanker …