Reducing avionics system development risk is key to winning the Joint Strike Fighter (JSF) competition. So Boeing is honing its entry by using full mission simulations to provide instant updates, while readying another airborne flying laboratory to verify the results.
The simulations are to demonstrate how its overall JSF weapons system will perform in a variety of threat environments and combat situations, feeding input from customer pilots into software changes and updates. Later this year, following the lead of its F-22 flying avionics testbed (Avionics Magazine, April 1999, p. 30), Boeing will begin flying its JSF Avionics Flying Laboratory (AFL), a modified 737 jetliner, to demonstrate JSF avionics performance in a real-time dynamic environment.
Boeing’s design combines on-board and off-board sensors with cockpit and helmet-mounted tactical displays. The combination is designed to give pilots unprecedented situational awareness and enhanced targeting information, with emphasis on the air-to-ground attack mode.
Boeing currently is refining this cockpit design and its software in the four-year concept demonstration phase of the JSF program. While defining the operational JSF, Boeing also is building two X-32 proof-of-concept flight demonstrators, with the first flight targeted for April 2000.
Boeing’s JSF competitor is a Lockheed Martin-led team that includes Northrop Grumman and British Aerospace. The winner will be selected in 2001.
JSF is a joint U.S. Air Force, U.S. Navy, U.S. Marine Corps, and UK Royal Navy and Royal Air Force program to develop a common, next-generation stealth attack aircraft that will be produced in three slightly different variants.
One version, a conventional takeoff and landing (CTOL) aircraft is designed for the U.S. Air Force to replace the F-16 and A-10 and complement the F-22A. A similar version will be produced for the U.S. Navy to complement the F/A-18E/F. A short-takeoff and vertical landing (STOVL) variant is intended for the Marines to replace AV-8Bs and F/A-18s, and for the Royal Navy and Air Force to replace Sea Harriers and the GR.7. As many as 3,000 JSF aircraft could be built, it is estimated, with production deliveries starting in 2007 and operations to begin in 2009.
Cockpit Design
The cockpit features two large 8-by-10-inch liquid crystal displays (LCDs) side-by-side and two smaller 3-by-4-inch LCDs above those, along with an up- front control panel. There is no head-up display (HUD) in the cockpit because the HUD information is integrated into the helmet-mounted display (HMD) and shown on the helmet visor.
With "affordability" vital, Boeing plans to use commercial glass for the head-down displays, and in its simulations it is depending on automatic source code generation to quickly make software updates or changes. In its cockpit design, Boeing is stressing a PVI (pilot-vehicle interface) that puts the pilot in the center of the loop, according to Marshall Williams, PVI team leader.
"We give the pilot an integrated battle space picture – offensively and defensively. We are showing how the systems can be operated by one pilot, in a single seat. We do that by automation, sensor fusion, automatic sensor tasking. This allows the pilot to be a tactician, not a sensor fuser or sensor manager," Williams says.
Unlike those on older aircraft, JSF avionics systems don’t operate on their own separate processors. In Boeing’s JSF they will operate off a single ICP (integrated core processor) – supplied by Raytheon – similar to that in the F-22’s avionics design.
Boeing’s HMD (see cover) provides primary flight, defensive threat, and target information, along with the ability to read the night vision scene without using night vision goggles. Multiple infrared (IR) sensors mounted around the aircraft provide a panoramic view, "so wherever you look, you can see the world," Williams notes. "It allows you to ‘look through your wings’…for landing purposes or weapons deployment."
While "flying" in Boeing’s cockpit development station (CDS) with the helmet on, if the pilot’s head is level or looking up, flight information normally displayed on a HUD is at eye level. Looking sideways or down, the pilot sees the infrared picture of the terrain.
The helmet, which receives its input from the air vehicle, is being designed to Boeing specifications by Marconi Electronic Systems, which is testing a similar device on the Eurofighter 2000 Typhoon. All information can be displayed both head-up on the HMD or head-down on the cockpit displays. A voice recognition system, part of the aircraft’s intercom system, is integrated into the helmet, allowing the pilot to call up any display.
Boeing has nearly finalized its cockpit design, Williams says. "We did a major display trade last year, changed the display configuration. As far as hardware, I don’t think there will be any [other] major changes."
Customer requirements have been changing, as well, he says. Boeing’s preferred weapons system concept continues to evolve with small updates and "ultimately [the weapons system] will be what we are going to propose, what we will be building."
The company borrows from its experience as avionics integrator for the Air Force’s F-22 air superiority fighter. Sensor fusion and data link technologies, including an intra-flight data link, have been designed for both aircraft. Boeing is also calling on its avionics heritage in the B-1, B-52 and its helicopter programs, as well as in the former McDonnell Douglas F/A-18, F-15 and AV-8B aircraft.
Suppliers
While suppliers of avionics and other components in the JSF will not be locked up until the winning team is selected and EMD (engineering and manufacturing development) begins, Boeing announced in Paris last June that 25 aerospace companies had joined the Boeing JSF industry team.
Avionics and weapons system suppliers include: AlliedSignal, subsystems; Dowty Aerospace (UK), flight control actuator; EDO, weapons bay swing arm system; Fokker (The Netherlands), wire bundles; Harris, PVI network interface cards; Honeywell, prognostics and health management (PHM); Sanders, electronic warfare (EW); Sundstrand, subsystems; TRW, communication/navigation/identification system (CNI); and Marconi (UK), vehicle management system and cockpit displays.
While the radar system supplier has not been officially selected, the radar Boeing will be using on its airborne flying laboratory (AFL) is part of a family provided by Raytheon. (Raytheon also provides the IR sensors.) Again, affordability and performance are the key factors, and system architecture would allow another radar to be incorporated.
Simulated Demos
Key elements in Boeing’s risk reduction effort are the full mission simulations of its operational (preferred weapons system) concept for the JSF. Last May, Boeing completed the third in a series of four planned week-long simulations at its Seattle facilities. Pilots from the various customers flew some 40 missions using operational scenarios to evaluate integration of avionics, PVI and mission software. Boeing demonstrated new functions for two-ship operations: its intra-flight data link and its off-board data information concept.
Automatic code-generating tools were used that allowed simulation changes to be made the same day. To make the quick changes, Boeing employs Designers Workshop, a commercially available three-dimensional drawing package provided by Centric Software.
"We have the ability in simulation to manipulate – for example, the size of the radar array – to determine the right sizes to do the missions required. We can manipulate the avionics while the pilot is ‘in the air.’ This is part of the affordability solution," Williams says.
The FMS can simulate all types of planned JSF missions – Air Force, Navy and Marines. But Navy carrier landings are not simulated. All "up-and-away" flying – with decisions on whether to avoid, engage or return to base, and actual carrier landings or takeoffs – are experienced in a separate full dome simulator called the X-32 handling qualities simulator, Williams explains.
In its demonstrations, Boeing has linked its full-dome mission simulator with its cockpit development station to allow pilots to "fly" two-ship missions. Also, manned work stations simulate pilots flying "threat" aircraft. One demonstration emphasized Navy missions and included theater air defense, suppression of enemy air defenses, and short-range and limited-long-range air-to-ground missions. Prior demonstrations have focused on Air Force and Marine requirements. The fourth full mission simulation is scheduled for next April.
The U.S. Department of Defense (DoD) supports simulation-based acquisition to reduce time, resources and risk. "These simulations allow us to involve the real war-fighters," says Cmdr. Ron Unterreiner, the U.S. Navy operational requirements officer who coordinates pilot participation in demonstrations for DoD’s Avionics Flying Laboratory.
Avionics development during the JSF’s current concept demonstration phase will culminate in a series of tests beginning later this year, using the JSF Avionics Flying Laboratory. Testing in this environment is intended to provide an early opportunity to detect targets under realistic conditions, years before the operational JSF is delivered to the customer, according to Daniel Cossano, Mission Systems team deputy. Six months of AFL flight testing will probably overlap flying of the X-32 demonstration vehicles.
"The X-32 will not have any mission avionics. It won’t be doing what we are doing in the AFL," says Cossano. "We will be bringing a good portion of the systems together with the PVI. We will bring the [EW], some IR, the radar and integrate it into the real environment."
The AFL requires a 4-foot (1.2-meter) nose extension, using the 737’s existing radome to house the radar array, and radar electronics behind. The electronic warfare system is on the bottom and the distributed IR system is on top.
The 737-200 required some structural modification for the nose extension to carry more than 2,000 pounds (907 kg) of avionics equipment, which is liquid cooled. A conventional diesel engine mounted in the aft of the aircraft provides supplemental power for the avionics equipment. The integrated core processor (ICP) for the avionics systems is installed in the cabin.
The AFL cabin will accommodate 20 to 25 engineers and have a "cockpit," with a stick, throttle and helmet for the operator. While the operator won’t fly the airplane, he will see some of the IR picture and some HMD imagery. There will be a camera mounted in the cockpit window, with a cabin display to show where the aircraft is headed.
The avionics test director will be able to show displays from all work stations, and communicate with ground stations and airborne targets. He also can view telemetry from various targets to determine how well the systems are tracking.
"We can put a lot more instrumentation on this [737] than we could on a small fighter," Cossano asserts. "We will be flying a lot of the systems pre-EMD. We will validate concepts, including sensor fusion – both air-to-air and air-to-ground.
"This is the only place we can test in a dynamic environment," he adds. "That’s even more important in the air-to-ground mission. You have to have the airborne velocity."
The AFL is being configured as a "company asset," Cossano concludes, to be used for other Boeing programs in the future, in addition to JSF.