How intelligent is the combat cockpit going to become?
Douglas Barrie/LONDON Julian Moxon/PARIS Graham Warwick/ATLANTA
A late 1980s' slice of Hollywood Cold War melodrama (Firefox) had film star Clint Eastwood stealing the Soviet Union's next-generation combat aircraft. In the ensuing chase, Eastwood has to "think" in Russian to launch his air-to-air weapons.
In reality, Russia's next-generation multi-role fighter, Mikoyan's 1.42, is hamstrung by a desperate lack of funding. A first flight early this year is likely, but advanced cockpit technologies on a par with those portrayed by Hollywood remain a mere glint in the avionics designer's eye.
This is not to say, however, that little advance is being made in the design and development of the combat-cockpit environment. The latest combat aircraft in development - the Eurofighter, the Lockheed F-22, the Saab JAS39 Gripen, the Mikoyan 1.42 and the Dassault Rafale - will all place the pilot in an environment considerably different to that of the previous generation of fighter aircraft.
When the McDonnell Douglas F-15A entered service in the mid-1970s, it was the apogee of Western combat-aircraft design. The cockpit was dominated by a plethora of "knobs and dials", with a single display screen high on the left-hand side of the cockpit front panel. In its latest incarnation, the F-15E, the cockpit environment has been redesigned. There are fewer "knobs and dials", with flat-panel displays now the predominant technology.
In the case of the F-15's eventual successor in the air-superiority role, the F-22, the cockpit environment will be dominated by large full-colour liquid-crystal displays (LCDs), with few traditional instruments in evidence.
The move to the screen-based data display, however, is merely the visible evidence of a much deeper trend, nominally referred to as a "sensor-data fusion", intended to provide the combat pilot with the information to carry out his role successfully.
Yves Thiriet, Dassault's senior vice-president for research, design and engineering, says: "Most of the effort has been concentrated on visual areas because the best correlation a human is capable of is with the eyes. Most of the organisation of a modern fighter-aircraft cockpit is now done on the screen."
John Mabberley, managing director (operations) at the Defence Research Agency (DRA) in the UK, notes that integrating the pilot into the system "...is a complex and very challenging requirement" and covers both the "...presentation of data in an understandable form and the selection of the data in a timely manner and in a form that suits the circumstances".
The next-generation combat aircraft will have an array of on-board and off-board sensors which will be capable of providing data to the pilot across the electromagnetic spectrum and at ranges previously only dreamed of.
The F-22 will have a Westinghouse active-array antenna with a capability beyond that of the F-15C/E's Hughes APG-70 airborne fire-control radar. While the US Air Force has dropped an infra-red search and track (IRST) sensor from the initial requirement, the four-nation Eurofighter will enter service with both a multi-mode pulse-Doppler radar and IRST, as will the Rafale.
The French air force has sought improved sensor-data fusion for the Rafale, specifying the Thomson-CSF/Dassault Electronique RBE 2 radar, IRST, integration of missile-seeker information and incorporation of the SPECTRA electronic-countermeasures system.
Such developments will provide the pilot with both active and passive means of target acquisition and tracking, but they could also contribute to what, in a high-threat environment, will be an already demanding cockpit workload.
A too-demanding workload is a potential problem which air forces wish to avoid, and which industry is trying to address. Eric Brydon, a member of the UK Industrial Avionics Working Group (British Aerospace, GEC-Marconi and Smiths Industries), said at a recent Shephard Military Avionics conference that there are now "...more intelligent systems offering the aircrew a greater situational awareness and tactical options. They rely on a high level of sensor fusion and it is in this area that we should see a technology breakthrough."
Programmes such as the UK's Mission Management Aid, the US Pilot Associate program and France's Co-pilot Electronique are all aimed at addressing these issues.
What has proved problematic in the past is the lack of maturity in many of the technologies which could be applied to reduce the amount of unstructured data reaching the pilot, and in improving the "human/computer interface".
Technologies such as artificial intelligence (AI) and direct voice input (DVI) have clear applications in the combat cockpit, but only if such systems can be shown to have reached the required level of maturity.
In the case of AI, there have been several "false dawns", in both the civil and military environments. AI-based systems could be used to mediate between the aircraft's sensors and the pilot, classifying and ordering hostile radar threats. Systems could also be used to control and deploy active and passive countermeasures.
What is more likely to emerge in the near-to-medium term is the use of "federated" processing to provide an "intelligence aid" to the pilot. On-board sensor information on actual threats could be fed via datalink to an aircraft such as the Boeing E-3 Airborne Warning and Control System, or the Grumman E-8 Joint Surveillance Target Attack Radar System. These could provide off-board processing of actual threat data to provide near-real time mission management.
In the mid-term, AI-based systems are likely to be introduced. Thiriet says: "The on-board EW [electronic warfare] computers should throw up priorities for decision making. The pilot would then be able to request [possibly by speaking] a list of options from the aircraft's integrated-warfare system." He sees this type of system being introduced as part of a Rafale mid-life update.
The US Air Force, the French air force, the Royal Air Force and the Russian air force are attracted by DVI and all are looking at the technology for inclusion at some point in combat aircraft now under development. Thiriet says that a considerable amount of work is being done on "...voice-activated functions for setting radio frequencies, and so on", for the Rafale
Voice-activated systems, such as for missile launch, could save time because no manual command inputs are required. In a close-in infra-red-missile engagement, the pilot who fires his missile first is likely to emerge as the victor.
Part of the problem with DVI is how to ensure that a command is unambiguous. As one senior USAF officer points out, there is not much difference between "shoot" and a four-letter expletive in certain US regional dialects. How a DVI system deals with this has yet to be determined.
Even before the RAF's next generation of combat aircraft, the Eurofighter, had taken to the air in 1994, the service had begun pre-feasibility studies to meet its next strike-aircraft needs to replace the Panavia Tornado GR.4. This is known as the Future Offensive Aircraft (FOA).
Brydon says: "The pilot of the FOA will have to acquire and maintain situational awareness to cope with the ever-increasing complexity of the battlefield scenario."
As if this were not enough, cockpit-avionics designers will have to accept the distinct possibility that the aggressor's weapon and sensor capability "...is expected to improve to the point where effective electro-optical and electromagnetic weapons will prevent the pilot using a direct view of the outside world in future high-threat regions".
To meet electro-optical threats, visor technology capable of countering known-frequency lasers is already being flown. An agile- frequency electro-optical threat, however, presents a far greater challenge, even against a visor capable of responding to variable frequencies. The response window required to prevent eye damage is narrow.
Designers spent years developing systems to get the pilot in a head-up mode, to provide him with as much time as possible looking outside the cockpit. Now, the designers have to contemplate the possibility of shutting out the outside world, at least for the strike/attack role.
This could mean either "closing" the cockpit or designing the pilot's advanced helmet to provide generated images only. Thiriet says that Dassault has carried out paper studies into "windowless cockpits", adding that such an approach also has design benefits. "The canopy is a pest for designers because it induces drag, and increases fuel consumption significantly," Thiriet adds.
Such an approach, taken to its logical conclusion, would remove the most vulnerable subsystem on the aircraft: the pilot.
Thiriet, however, remains in no doubt that a pilot will remain at the heart of combat aircraft. "Only a pilot can take care of unexpected events and only a pilot can take decisions where the data input is vague. Computers are still no good at answering the question of what it looks like, or sounds like."
In dealing with a hostile electro-optical environment, the look-out mode - through the head-up display (HUD) would be replaced by what Brydon describes as a "virtual-world display". He adds: "Virtual-helmet-mounted and large-format head-down displays must be explored to provide intuitive low-workload, high-situational awareness, presentations."
Brydon does not underestimate the size of the task, saying: "This will remain a large human-factors problem for some years yet."
Programmes are under way to determine and quantify the element of technical risk in such an approach, and also to examine the impact such a system has on its operator.
The UK's Advanced Panoramic Helmet Interface Display System (APHIDS) is a technology-demonstrator programme being run by the DRA and led by GEC-Marconi. The programme is to develop a 60¡-field-of-vision panoramic helmet-mounted display with which to examine "virtual cockpit" concepts and to evaluate the impact such a system has on pilot performance.
The Eurofighter helmet will have a 40¡ binocular field of view (FOV), while the Rafale helmet will have a 30¡ monocular FOV. In part, the DRA's APHIDS programme is also intended to identify the cut-off point beyond which an increased FOV does not elevate operational capability enough to justify the increased technical complexity and cost.
Along with research into expanding the pilots' FOV provided by the helmet, there is also a general consensus that the multi-function display screens will also get larger. The Eurofighter will be fitted with cathode-ray-tube (CRT)-based displays, a conservative approach which belies the much-heralded and oft-repeated death of the CRT. The Rafale will go straight to LCD technology.
The "big screen"
Thiriet says that Dassault has looked at the "big-screen" concept, coupled with a three-dimensional format. "It will take time to re-educate pilots away from the two-dimensional images they are used to," he admits.
So far, three countries have fielded helmets which have incorporated an advanced system normally associated with a manual cockpit task in operations. This is the helmet-mounted sight in service with Israel, Russia and South Africa, although several other nations have research-and-development programmes in progress. The USAF is now firmly in their favour.
The emergence of the helmet-mounted sight marks the beginning of a further shift in the way in which data are displayed to the pilot, and pilots' ability to react. Future combat-aircraft displays will consist of two or three multi-function display systems: large flat-panel LCD displays, head-up/head down displays and helmet-mounted display systems.
There is a debate as to whether the advent of advanced helmet displays heralds the end of the HUD. The USAF, under the auspices of the Joint Advanced Strike Technology programme, for instance, will explore the interaction between helmet-mounted displays and the HUD.
HUD advocates within the avionics industry argue that the accuracy and resolution of primary flight instrumentation displayed on a HUD will be beyond that of advanced helmet-mounted systems. They also claim that using only a helmet-mounted sight in targeting places extra strain on a pilot's neck muscles.
The Russian air force, among the first to field a simple helmet-mounted sight, is also working on next-generation cockpit technology, although Russian combat cockpits have not previously been noted for the early deployment of advanced systems. The Russian air force has usually adopted a conservative approach, with "dials and knobs" still the predominant feature in its present front-line aircraft. Monochrome display screens have begun to appear in upgrades of aircraft such as the Mikoyan MiG-29M and MiG-31M. The Sukhoi Su-34 and the Su-35 also have multi-function screens as the primary cockpit instrumentation and displays.
Although so far no full-colour screen has been seen in a prototype cockpit, examples of such systems have been displayed "on the bench".
The Russian air force talks openly about the need for an advanced cockpit, capable of reducing pilot workload while providing improved reliability and reduced life-cycle costs. Along with the use of high-speed parallel processors to provide the requisite computing power, the air force is also examining DVI. It identifies two main problem areas in this technology: pilot stress, coupled with voice distortion and the need to filter out background noise. Given funding and technology constraints, Russian combat-aircraft cockpit design is likely to continue to lag behind that of the West.
The "thinking cockpit" flown by Clint Eastwood in Firefox remains in embryonic form in the laboratory. Ironically, the backward-firing weapon he uses to dispose of his pursuers is much more advanced in Russian missile manufacturer Vympel's rearward-launch variant of the R-73 (AA-11 Archer) is now under test.
Flat displays get a lift
Space has been created in the combat cockpit for flat-panel displays, but operational experience is still limited and production is in its infancy. More than 20 military-aircraft programmes use, or plan to use, flat-panel displays.
Early applications capitalise on the advantages of the liquid-crystal display (LCD) over the cathode-ray tube (CRT): in helicopters, lower weight; in fighters, sunlight readability; in transports, increased reliability.
Simply put, LCDs weigh 40% less, occupy 40% less space and consume 40% less power than CRTs. In military-aircraft applications, the mean time between failure (MTBF) is likely to exceed 5,000h, compared with 1,000-1,500h for a CRT. Other advantages include improved display readability in direct sunlight and the capability to present sophisticated graphics.
There are disadvantages, but these are being overcome with the rapid advance in LCD technology, driven by the market for commercial displays in applications such as lap-top computers. Colours are still not as rich as those produced by CRTs and the viewing angle remains limited. While not a problem in the confines of a fighter cockpit, cross-cockpit viewing in a transport has required the development of sophisticated optical coatings.
There are three manufacturers of avionics-grade "glass": Litton Systems Canada, Optical Imaging Systems (OIS) in the USA, and Thomson in France. In addition, US-based Electronic Designs "ruggedises" glass supplied by Sharp of Japan, the biggest producer of commercial LCDs, for avionics use.
In general, these companies supply glass to avionics manufacturers, which produce the finished displays. OIS supplies glass to major display manufacturers AlliedSignal Aerospace, Honeywell, Kaiser Electronics and Smiths Industries, while Thomson supplies Sextant Avionique. Litton differs in producing glass for use in its own displays.
OIS has won a $48 million US Advanced Research Projects Agency contract to build a production line for avionics-quality LCDs, the publicly traded company putting up the rest of the plant's $100 million cost. Displays will begin rolling off the production line late in the third quarter of 1995 and the plant will have the capacity to produce 40,000 150 x 200mm displays a year.
As the only US source of LCDs, OIS has the lion's share of the domestic military flat-panel market. The company has agreements to supply glass to AlliedSignal for Boeing CH-46 and Lockheed C-141 cockpit upgrades; to Honeywell for the Bell/Boeing V-22 and Lockheed F-16A/B; and to Kaiser for the Lockheed/Boeing F-22 and McDonnell Douglas F-18E/F.
Litton entered the LCD business in the mid-1980s by acquiring the rights to technology developed by Westinghouse. Initial experience was not encouraging - the Canadian company was display supplier to the losing Northrop/McDonnell Douglas YF-23 Advanced Tactical Fighter and McDonnell Douglas/Bell Light Helicopter Experimental teams and to Boeing for the cancelled Update IV programme for the Lockheed P-3C.
Fortunes improved in the early 1990s, when Litton was selected by Harris to supply displays for the Boeing/Sikorsky RAH-66 Comanche; by Loral ASIC for the Agusta/Westland EH101 Merlin; and by Lockheed Sanders for the Lockheed C-130J Hercules 2. Litton's LCD production plant is scheduled to be completed in February, with the first displays rolling off the line by July. Capacity will be around 5,000 LCDs a year.
LCD applications are on the increase. Major programmes pending in the USA include the Bell AH-1W, McDonnell Douglas AH-64 and Northrop T-38 cockpit upgrades. Internationally, LCDs are fast becoming the display of choice. AlliedSignal will use OIS glass in 100 x 100mm multi-function displays to be supplied to Lockheed, for Argentina's McDonnell Douglas A-4M upgrade, and to Rockwell, avionics integrator for the Czech Republic's Aero L-159.
Sextant, which supplies flat-panel displays for the Dassault Rafale and Eurocopter Tiger, has been selected to provide similar equipment for India's indigenous Light Combat Aircraft. Litton's contract with Loral is to supply rear-cabin mission displays and cockpit pilot-repeater displays for 44 Merlin helicopters for the Royal Navy.
How to make intelligence data accessible
Successful technology demonstrations have fuelled enthusiasm for the concept of making intelligence data from satellites available in the combat cockpit, but work remains to be done on how such information can be presented effectively.
A series of US demonstrations, under the umbrella concept of real-time information in the cockpit (RTIC), has shown that satellite data can be relayed to an aircraft to allow the pilot to update the mission plan, avoid air defences and attack an unseen target. A parallel effort is under way to develop an airborne supercomputer capable of filtering and fusing onboard and off-board sensor data to produce a useable picture.
Under the designation Talon Sword, a series of "satellite-to-shooter" technology demonstrations was conducted in 1993-4. In one, a US Navy Grumman EA-6B crew used satellite over-the-horizon targeting data to attack a patrol boat with an AGM-88 HARM anti-radiation missile. In another, satellite data were received by a US Air Force Constant Source ground-station, retransmitted to a Lockheed F-16 and used to launch a HARM beyond visual range.
In one Talon Sword demonstration, an EA-6B crew correlated satellite targeting data with onboard sensor data to identify and locate an emitter, then transmitted the information to an F-16 via the improved data modem (IDM). The F-16 pilot then fired a HARM at the simulated radar site, which was beyond visual range.
The ultimate Talon Sword demonstration, in July 1994, was the most complex. Satellite data were used initially to plan an attack on an air-defence-missile site. In planning the attack, the crew of a Navy Lockheed P-3 used satellite data to cue a long-range electro-optical sensor to confirm and refine the locations of air defences en route to the target. These were transmitted via IDM to an inbound F-16, along with a satellite image of the target area. Final orientation for the bomb attack was provided by a video image of the target transmitted from the P-3's electro-optical sensor to the F-16. In the final phase of the demonstration, satellite data were used to plan a "clean-up" raid.
The follow-on to the Talon Sword is the Talon Lance, a programme to demonstrate the RTIC technology needed to distribute satellite intelligence to combat aircraft. Loral Electronic Systems is prime contractor for the Talon Lance, which began in mid-1993 with a demonstration of the concept of an on-board supercomputer. Taped data from 1991's Desert Storm and live satellite broadcasts were processed and presented on an aircraft-type multi-function display.
Talon Lance testing is progressing from a ground-based flight simulator using a commercial processor, via an airborne testbed using a prototype supercomputer, to an operational flight-demonstration using a flyable processor. The eventual aim is to develop a single computer card with the power of two Cray supercomputers, operating up to 30 times faster than the computers on today's aircraft.
Two USAF technology programmes are supporting the Talon Lance. The Advanced Defensive Avionics Response Strategy (ADARS) programme is developing software modules to correlate onboard and off-board sensors. The Electronic Warfare Preprocessing Elements programme is developing a modular, scalable, open-architecture avionics supercomputer. Loral is prime contractor on both programmes.
The main objective of the ADARS is to improve aircraft self-protection. The demonstration system correlates information from the aircraft's ALR-56M radar-warning receiver, AAR-47 missile- approach-warning system and ALQ-131 electronic-countermeasures system, using satellite intelligence data from a Constant Source ground-station to fill in the gaps, then performs threat assessment and cues the self-protection suite. ADARS software is being developed so that it can be used in new and retrofit applications.
Satellites can provide data on threats and targets well beyond the range of the aircraft's on-board sensors and can be used to cue those sensors to increase their effectiveness. Other off-board sources of data which the USAF hopes to exploit include Boeing RC-135 Cobra Ball infra-red and Rivet Joint electronic-intelligence aircraft, the Boeing E-3 Airborne Warning and Control System and the Northrop Grumman E-8 Joint Surveillance Target Attack Radar System (JSTARS).
While the USAF is concentrating efforts on using off-board sensor data for self-protection and defence-suppression, the US Army has launched a major effort to "digitise" the battlefield by enabling troops, tanks and helicopters to communicate digitally.
The Navy-developed, USAF-procured IDM, manufactured by Florida-based Symetrics Industries, plays a key role in the Army's plans. So far, the IDM has been used to transfer data between McDonnell Douglas AH-64D attack helicopters; between an AH-64D and a Sikorsky UH-60V command-and-control helicopter; between an AH-64D and an E-8 JSTARS; and between an M1 tank and a Bell OH-58D scout helicopter.
The Army plans to use digital communications to transmit weather, target and threat data directly to the cockpit to increase situational awareness and to turn combat aircraft into intelligence-gathering assets.