Hailed as the world’s most advanced fighter pilot helmet, Striker II has an all-digital display with an integrated night vision system geared towards transforming aerial combat, writes Stuart Nathan
The cockpit of a fighter aircraft is one of the most high-tech environments in the world. Pilots have to cope with an avalanche of information, from the view outside the canopy, to the instrument displays in front of them, feedback through the manual controls, and the various noises – including alarms – inside the cockpit. In future, however, some pilots will have an important aid to help them make sense of all this and avoid total sensory overload: the Striker II helmet.
Developed by BAE Systems’ electronic systems base at Rochester in Kent, Striker II is, as the name implies, a development of the Striker system which was originally designed for pilots of the Typhoon aircraft. “Obviously, products change to reflect the introduction of new technology,” explained project manager Richard Orridge. “It wasn’t that Striker was doing a bad job, it’s more that with the advent of digital technologies we could make it a lot better.”
The role of helmets like Striker and Striker II is to provide a display system to replace the heads-up display which projected information at the pilot’s eye level onto the inside of the aircraft’s canopy. Essentially, this is augmented reality. Symbology representing other aircraft – friend or foe, mission targets and incoming armaments, as well as targeting devices, are overlaid so that the pilot can understand intuitively all the information he or she needs that may not be visible to the naked eye or might require highlighting to ensure that it is not missed.
In the original Striker, that display was a small cathode-ray tube mounted inside the front of the helmet at the correct distance for the pilot to focus upon. This, Orridge explained, is essentially an analogue device: the display is formed by a ray of electrons electromagnetically rastered across a screen treated with a fluorescent phosphor. In Striker II, however, this is replaced by a 4K digital display. The outside view is provided by cameras on the exterior of the aircraft, and the symbology is overlaid digitally.
This presents a number of advantages, Orridge said. “First of all, we can do the symbology in colour; previously it was monochrome. Moreover, digital display is much lighter in weight than the CRT.” Use of colour allows more information in the symbology: friendly aircraft can be represented in blue, hostiles in red and ground features in green, for example. This improves reaction times to threats and reduces the chance of “friendly fire” incidents. Another major advantage is that the field of view is much wider than with the CRT system.
Going all-digital also allowed the developers to overcome one of the major disadvantages of Striker. The helmet was equipped so that it could be paired with a night vision system, but this was literally placed onto the helmet and had to be pulled down in front of the eyes by the pilot. This was not ideal, explained chief systems engineer Colin Mills. “The night vision goggles are quite heavy, and mounted on the front of the helmet put it out of balance and tended to strain the pilot’s neck,” he said. “And even more seriously, the pilot would have to remove the goggles before ejecting in an emergency, and we would much rather they were able to just press the button without having to worry about anything else.”
The symbology moves smoothly as the pilot looks around, with no jittering or timelag
In Striker II, the night vision system is integrated into the helmet and located between the pilot’s eyebrows. This not only removes the need for cumbersome extra goggles, it allows the weight to be reduced significantly and distributed so the helmet is balanced perfectly when the pilot’s head is in a neutral position.
Among the other digital effects available to the 4K display is an image-in-image system that is brought into play during missions where the pilot has to fire armaments. As the aircraft gets into range of the target, the crosshairs the pilot sees are augmented by a small black-and-white pop-up image of the target area, so that he or she can be sure that when missiles are dispatched, the chances of collateral damage are minimised.
Overlaying symbology and other information into the pilot’s field of view requires that the system knows the position of the pilot’s head precisely. In the old Striker system, this was done using infrared sensors mounted around the cockpit to detect and map head position. One drawback with this, Orridge said, was that the pilot’s oxygen hose can sometimes get in the way of the detection system. In Striker II, the sensor system is augmented by an onboard digital position system using accelerometers, similar to those found in smartphones. This allows head position and orientation to be tracked precisely with little to no latency, Orridge said. “The symbology moves smoothly as the pilot looks around, with no jittering or timelag.”
The system also allows tricks that would not be possible with Striker. Cameras mounted around the entire exterior of the aircraft allow the pilot to effectively “look through” the floor of the cockpit, allowing 360° awareness.
The new helmet is also equipped with “3D sound”, so that should another aircraft or an air-to-air missile be approaching from behind, the pilot receives the illusion of the sound arriving from the appropriate direction.
Striker II was initially developed for the Typhoon, which is currently undergoing a systems upgrade, and the Swedish Saab Gripen fighter, but the Rochester team is also developing it for the F 35 Lightning II, with the only major change anticipated being in the mounting points for the intercom and oxygen mask. “It is designed to be a platform-agnostic system,” said Mills.
Other aircraft that would benefit from the use of this helmet are rotorcraft, added Jean Page, head of human factors at Rochester. “The display system would be a distinct advantage on take-off and landing, where you can have the problem of whiteout in snowy conditions and brownout in dusty and desert environments. In both cases, particulates are blown up by the downdraught and completely cut out the pilot’s view. We can use the wide viewing angle of the display to give an enhanced image,” she explained.
The display system would be a distinct advantage on take-off and landing in rotorcraft
The system is also an integral part of BAE’s ambitious plan for future cockpit environments: a “virtual cockpit” where the physical displays and dials and even switches are replaced by a graphical representation on the helmet display.
In this case, Page explained, the head tracking system might be augmented by gaze detection to determine precisely where the pilot is looking, while extra sensors track his or her hands and fingers to detect whether a switch is being manipulated. “We would augment the system with haptics to give the sensation of pressing a switch,” Page said.
Virtual cockpit is planned to be part of the ongoing upgrade of Typhoon, and may be used in the new Tempest aircraft which is now being developed to succeed Typhoon in future decades. It will also allow displays suited to different anticipated roles for fast jets, including mission overview and control of drone swarms in the battle space. Additional displays could be moved around the pilot’s field of vision to suit the mission; for example, a dedicated display might appear to assist with in-air refuelling.
However, ultimately Orridge and Mills are keen to stress that Striker II is primarily a piece of protective equipment. “Its first job is to keep the pilot’s head safe,” said Mills. “It has to ensure that they can function when they are pulling 9G in manoeuvres, and most importantly it offers protection in the case of ejection. That’s a highly hostile situation where the pilot is subjected to very sharp acceleration, deceleration and possible impact. As soon as the pilot leaves the aircraft, their head is instantly placed into an airstream moving faster than 600 miles an hour.
“We have to ensure they are fully protected from that. In developing the helmet, its performance for those situations was the absolute primary concern, and getting all the electronics into it and making sure that none of them compromised that function was almost a bonus.”