Tuesday, June 1, 2004
Will Projection Displays Give F-35 an Edge?
The Joint Strike Fighter flight deck display will set precedents for sheer size, controllability and ease of use. Will the calculated bet on projection display technology pay off for this major multinational program in the long term?
Prime contractor Lockheed Martin and avionics provider Rockwell Collins are placing a calculated bet that their new flight deck projection display technology for the F-35 Joint Strike Fighter (JSF) will result in a better, lighter and less expensive aircraft.
And despite some doubts from other quarters, the U.S. and UK defense departments are moving ahead with plans to fly 15 projection display-equipped fighters beginning in the summer of 2006 in the JSF program's system development and demonstration (SDD) phase. The F-35 is to be produced in three variants—conventional takeoff and landing (CTOL), carrier-based, and short takeoff/vertical landing (STOVL). Almost 2,600 of the aircraft are slated for the U.S. Air Force (USAF), Navy and Marines (USMC), and the Royal Air Force and Royal Navy.
"In the late '90s, we made a strategic decision that projection display technology was going to be a discriminator in cockpit advancement when it came to the mid-2000s," says Tom Frey, F-35 pilot systems integrated product team (IPT) lead for Lockheed Martin Aeronautics Co. in Fort Worth, Texas. Rockwell Collins, in San Jose, Calif.—formerly Kaiser Aerospace prior to its acquisition in 2000—was chosen to provide the F-35's multifunction display system (MFDS).
Using "reflective light" technology borrowed from the commercial TV industry, the Lockheed-Collins team is providing two adjacent 8-by-10-inch display surfaces built as one 8-by-20-inch viewing area—the largest display area in a fighter aircraft to date. "And we're at least 100 pounds [45 kg] lighter because of the way we've integrated our cockpit," Frey maintains. Employing touch screens (the first on a large-format display) and voice recognition, the team has been able to integrate many cockpit control functions typically found on switches into the displays themselves.
"In our simulations, this is the first cockpit I have worked on where the pilots haven't asked for more display area," claims Frey, who also worked on the F/A-22 cockpit. "A lot of it has to do with how efficiently we have set it up for the pilots to use," he says. Frey heads a team that includes nine cockpit engineering disciplines, ranging from ejection seats to flight controls. Another performance advantage touted for the projection display is brightness. It improves sunlight readability by a factor of two to three over conventional liquid crystal display (LCD) units in other fighters, Frey claims.
Avionics projection display technology originated in the 1980s, and some prototype displays were flown in several European aircraft. Currently, Thales Avionics provides projection-based head-up displays (HUDs) for Mirage and Rafale fighters and Airbus aircraft, as well as projection helmet-mounted displays (HMDs) for helicopters. But only recently has this technology been chosen by U.S. contractors. Rockwell Collins flew its first projection display system—a 6-by-6-inch reflective micro-LCD, projection-based "smart display"—on an F/A-18E/F Super Hornet in May 2002. However, future Boeing F/A-18 avionics block builds do not call for a projection display system.
Although not originally slated for the Lockheed Martin F/A-22, the Air Force's new air superiority fighter, a projection display unit has replaced the aircraft's original 8-by-8-inch, centrally mounted tactical LCD display. For the F-35, "more advanced, fourth-generation technology is being used," Frey says. "And if you take a look at projection displays compared to LCDs, you find this technology is coming to market and is going to be successful in fighter cockpits in a much shorter time span than LCDs ever were," he says.
Rockwell Collins MFDS
The total package Collins will provide for the F-35 includes the two 8-by-10-inch MFDs, a pilot interface module, and, for each display, a low-voltage power supply, lamp, cooling fan and igniter, and display processor—used to process all display management functions. Collins designed and will build the display processor.
These elements all plug into a backplane, or interconnect, that interfaces with the aircraft. On the front of the integrated MFD assembly is the pilot interface module that contains multiple pieces, which are combined to provide the reflective surface for the projection system. The primary surface is a chemically tempered glass substrate. Special optical coatings are applied to make the glass reflect the light in the right direction—towards the pilot's eyes. Collins procures the glass and coatings but builds the touch-screen electronics.
"The MFDS is the primary pilot-vehicle interface, used in conjunction with other JSF systems, including the helmet-mounted display system and voice commands from the pilot, to manage the JSF systems," explains Terry Harris, JSF/MFDS program manager for Rockwell Collins-San Jose. Tasks managed by the MFDS range from starting engines to displaying sensor data and systems status to the pilot.
Collins also developed software that is integrated into the display system by Lockheed Martin in Fort Worth or by team member Northrop Grumman in El Segundo, Calif. Collins provides the key projection lens assembly piece from its Kaiser Electro-Optical division in Carlsbad, Calif., and supplies the (three-card set) display processor circuit card assembly.
Collins played a role in prime contractor Lockheed Martin's decision to use projection displays in the F-35. "Rockwell Collins-San Jose is a display house, and when we receive an RFP [request for proposal], we take a look at the technology that's available and make the best choice, based on the ultimate requirements of the customer," Harris says.
"We try to use a stair-step approach," he adds. "And we've done that by taking the initial projection display technology used on the F-18 and F-22 and migrating that to a more advanced approach for JSF. We hope to take the JSF approach to the next level beyond that."
Last July (2003) Rockwell Collins won its first international projection display system contract, inking an agreement with Shimadzu Corp. of Japan to co-develop a 4.5-by-4.5-inch reflective micro-LCD projection-based display for the F-15J fighter. The display design will use highly rugged-ized, commercial off-the-shelf (COTS) projector components and technologies.
How it works
Projection display is an extension of the technology used for conference room projection systems. "It uses miniature display devices, in this case a miniature LCD to form an image, which is then magnified and projected onto a screen. "This provides us the flexibility to choose very high-resolution image devices and determine the final output display—in this case, two 8-by-10 displays," explains Tim Edwards, a technical director on Collins' MFDS program.
Like rear-projection TVs or conference room projectors, the projection equipment includes prisms, color filters, a lamp and a variety of optical components, including a projection lens to expand and illuminate the miniature LCD display device on the 8-by-10-inch screen. The resulting displays have a resolution of 1280X1024 pixels, typical of that found in a high-end laptop, or high-end desktop computer monitor, Edwards says. Depending on how the software is written, the F-35's 8-by-10-inch displays can be divided into "as many or as few [separate displays] as [the team members] choose, depending on how the Lockheed JSF team wants to view the different information needed," he adds.
To display this information, Lockheed Martin devised a concept called "portals" that allows the pilot to quickly adapt the format windows of the JSF's 8-by-20-inch display to make them smaller or larger. Pilots will be able to view sensor-supplied tactical and targeting information and threats, onboard weapons status, aircraft flight and status data, and caution and warning system alerts. While a common configuration would use four portals, each one can be expanded to take up a full 8-by-10-inch display, and then secondary window positions can be expanded or contracted—using touch, voice, or hands on throttle and stick (HOTAS) commands.
"The pilot, by touching a cyan [greenish-blue] triangle, can expand the portal vertically or horizontally and get to full 8-by-10 [display size] with one button push," explains Lockheed's Frey. The same can be done by voice. "The pilot can say `expand one'—that's the one on the left-most portal—and then, if you want to resume the same configuration, say `restore one,'" he adds. Using HOTAS, the cursor controller on the throttle is employed to "click on" the active touch icons to configure the portal. Voice and touch are designated as the primary modes of pilot input, and the cursor is the backup mode in case touch-screen and voice activation fail.
However, too much automation is not always a good thing, Frey warns. "Typically, we have found pilots really don't appreciate the display system's automatically changing formats on them. The pilot doesn't like to be surprised." He says the system does allow for major mode changes—like switching from a tactical mode to an instrument mode—with portals reconfiguring with both formats and size according to the pilot's last preference, "but other than that, we haven't found a need for additional automation, nor that it is advantageous."
While the F-35 features an 8-by-20-inch viewing area, the display system currently is limited by processing capacity to the two adjacent 8-by-10s. "We had looked at using a 9-by-16-inch HDTV [high-definition TV] format, but based on redundancy needs in the cockpit, we felt better off with two 8-by-10s built together as a single 8-by-20—you get more display surface for the same redundancy that we needed," Frey points out. The displays incorporate a zoom-in capability to make features larger.
The redundancy allows one computer to substitute for the other if it should fail. "When using voice recognition, for instance, the master display computer takes the digital voice stream coming in and does all the appropriate commands, and then the slave computer knows that, if the master goes down, it picks up those extra functionalities," Frey says.
Each 8-by-10-inch section of the 8-by-20-inch display has its own graphics processor and projection engine that create the symbology. The airplane's different sensors ship the video to the display system, which inserts it in the correct portal, Frey explains.
Using reflective LCD components direct from commercial sources obviates the need for the "unique design builds" that are required with the direct-view LCDs found in most fighters. While military transports have successfully used ruggedized commercial LCD displays, most fighter aircraft require special glass for their displays to withstand brightness and temperature ranges.
"[Projection display technology] really allows us to apply commercial technology without excessive military ruggedization or technology adaptation," Frey says. The end result? "Reduced weight, cost and size," he emphasizes.
Previously, delivery of Collins' MFDS systems was to begin at the end of June, but that schedule has slipped to October. However, a critical design review (CDR) has been passed, and companies on the JSF team now are tooling up to begin production for the SDD phase. The displays first will be test flown sometime next year on a Lockheed Martin modified Boeing 737 called CATBird (cooperative avionics test bed), according to Frey.
The first time the cockpit equipment actually flies in a fighter is when the A-1 aircraft takes off—scheduled for August 2006. At this point in the development schedule, avionics commonality across the three JSF variants has reached 98 percent. "Our goal in the cockpit is to be 100 percent," Frey says.
Lockheed Martin currently operates a cockpit demonstrator at its Fort Worth and Arlington, Va., facilities that is "flown" by military pilots to include their inputs in cockpit systems development. However, its display system uses commercial projection engines and "does not mimic the final projection engine we will build for the MFDS," says Collins' Harris.
Smiths Aerospace, of Cheltenham, UK, is providing the F-35's standby 3-by-3-inch active matrix LCD flight display system, which independently displays attitude, altitude, airspeed, vertical velocity and angle of attack. The display system is centrally located in the cockpit front panel. And VSI Systems International, a joint venture between Collins and Israel's Elbit Systems, provides the JSFs helmet-mounted displays.
Beyond JSF, is there a market for projection displays? "We've done a lot of work with a lot of different potential customers," says Harris. "We have other things in the works, but right now JSF is certainly the largest [customer]." And, as a major supplier for commercial and business aircraft, has Rockwell Collins considered projection display systems for that market? "It's possible," says a Collins spokesman at the company's Cedar Rapids, Iowa, headquarters. "But we don't have anybody working on it yet."
The JSF program office endorsed Lockheed Martin's decision to choose projection display technology for the F-35. The system's use of COTS parts "provides us with the flexibility in adapting it to the space constraints that you have with the F-35 cockpit," says USAF Lt.Col. Keith Weyenberg, F-35 vehicle systems IPT for the JSF program office. "Additionally, we felt that the technology provided us with a more cost-effective upgrade path, because you can upgrade components, such as the projection engine, as their technology improves, without replacing the entire display," he says.
A key projection system advantage is that "we're able to warm up—especially in cold weather—and be operational faster, an advantage for fighter aircraft when you are sitting on alert and want to start up and get to a fight as soon as possible," Weyenberg maintains. He concurs with Lockheed's Frey that the system also offers improved brightness. "There is more contrast there than with an LCD display. It's easier to see in a cockpit that's lit up by bright sunshine."
But the most significant breakthrough is that the F-35 "will be the first aircraft that meets the services' ideal of having a display surface that also is your instrument panel," Weyenberg says. "The portal concept provides flexibility to change displays [and] select weapons or different modes for the different systems on the aircraft through touch screen or voice [commands]," he explains. "You don't have to select different modes on your CRTs, as you do on some of our legacy aircraft, or go to other switches in the cockpit."
The new display system promises to be reliable as well, the JSF office says. The modular approach provides fairly easy access for maintenance technicians to uncover components and replace them, if necessary.
Although unable to cite a mean time between failure (MTBF) target figure at this point, "we've given Lockheed Martin some high-level reliability requirements and they have allocated those to different components on the aircraft," Weyenberg says. "Right now, based on our design analysis, they are meeting all their reliability specifications for this [projection display] system."
Revised Program Schedule
About 2,600 F-35s are slated for the U.S. Air Force (USAF), Navy and Marine Corps (USMC) and for the Royal Air Force and Royal Navy. The USMC previously was scheduled to achieve initial operational capability (IOC) by 2010, the USAF by 2011 and the U.S. Navy and UK forces by 2012. An ongoing "replan process," however, may shift the USMC IOC to 2012 and the USAF and U.S. Navy IOCs to 2013. The potential impact on the UK IOC was less clear at press time in early May. First flight of the lead aircraft is likely to move from late 2005 to 2006. More information is expected after a review of the program by senior Pentagon officials in mid-June.
Passing on Projection Display Technology
Honeywell wasn't dozing while projection display technology was being developed. In fact, the major avionics supplier took a good look at it but decided it wasn't right in the foreseeable future for its commercial air transport market.
"In 2000 we started to seriously consider projection," says Kevin Young, Honeywell's director of air transport systems displays. "We made sure that we did sufficient research to understand if it was a promising technology, and if so, we needed to proceed with developing those display systems that would utilize it."
The company "picked up a program" and evaluated the different technologies required for projection display systems. Eighteen months later, Honeywell felt it had categorized both the different technologies that could be mature and the problem solving that would be required to produce a display that would meet the needs of its marketplace.
"It just wasn't going to be a viable technology for anything that was on the horizon within our time scope," Young says. Key areas of concern involved the reliability and the alleged difficulty of maintaining a projection system. He cites the relatively short life span—8,000 hours—of lamps required by projection display systems to illuminate the magnified image. "For some marketplaces [this] probably would be acceptable, but in the commercial world, [it] would be totally unacceptable," Young maintains. "Airlines expect displays to have MTBFs [mean times between failure] of 20,000 hours or higher."
Honeywell also found the cost of projection display systems it was evaluating to be higher than for flat panel active-matrix liquid crystal displays (AMLCDs) the company was delivering. These studies also showed that the "complexity" of the projection system, requiring lenses and mirrors, added to the system's weight.
The studies, which ended in 2001, concluded that the technology wasn't ready, Young concludes.