TIM ROBINSON visits BAE Systems Rochester to find out more about next-generation lightweight HUDs and digital HMDs.  

BAE's Striker II - about to complete flight tests represents the apex of HMD technology (BAE Systems)

Situational awareness and human machine interfaces for fighter pilots have come a long way since the days of the first illuminated Revi gunsights. Today glass cockpits dominate, as well as head-up displays (HUDs). Helmet mounted displays (HMD), meanwhile, are now expanding from purely fighter and attack helicopter pilots to wider applications.

Yet these advances in cockpit and avionics technology have also come with challenges. Increasing sophistication and a need for 24hour operations means that HMDs and separate night vision goggles (NVGs) have now reached the limits of weight – increasing fatigue and potentially even risking a neck injury in an ejection. Meanwhile, as HUDs have increased in size, that, too, has brought its own issues, as cockpit designers attempt to fit ever larger-head down displays in the same restricted space.

BAE Systems at Rochester

Rochester is also the centre for BAE 'active inceptor' controls - which provide 'force feedback' and enhanced situational awareness for FBW aircraft (BAE Systems).

One company at the forefront of next-generation displays is BAE Systems – and its factory at Rochester, Kent, which designs, researches and manufactures HUDs and HMDs. Rochester is also responsible for flight controls and ground-breaking active inceptor sticks – which it produces for the F-35 and KC-390 among others, as well as the Gulfstream 500/600 business jets – the first-ever civil application for this new technology.

Rochester itself, which employs 1,500 people today, can trace its history back 70 years, when, as a Shorts factory, it produced the Stirling bomber in WW2. Becoming an avionics factory through Elliot Brothers and then Marconi GEC, it now rests in the US Electronic Systems arm of BAE Systems, rather than the Military Aerospace division.

Enter Striker II

HMD test cell at Rochester. Helmets are subjected to a demanding set of environmental tests. (BAE Systems)

Rochester is a centre of excellence for BAE‘s HMD business, producing the helmet that currently equips Eurofighter Typhoon and Saab Gripen pilots – and gives them the ability to designate targets wherever they look – and cue sensors whether it be radar or a targeting pod.

This is no dumb ‘bone-dome’. The absolute precision needed, along with the demanding environment it is used in, means that these helmets (which come in two sizes) are subjected to a battery of environmental (temperature and vibration) tests before they leave the factory. The helmets are subjected to +70degC and –40degC as well as 6G worth of vibration, before they are deemed to have passed.

Normally it takes 16 days to assemble a HMD, but BAE have made strides to optimise the production process – such as bringing suppliers on site and moving inventories to technicians. New tracker testing machinery has also reduced a two-day test and validation process to two hours.

Yet BAE is already working on the next evolution of this sophisticated piece of aircrew equipment – the Striker II HMD. Originally developed as part of an alternative helmet solution for the F-35, the Striker II was unveiled in 2014, and this HMD features a 40deg display and digital inputs – taking the previous analogue helmet into a HDTV world.

One HMD to rule them all?

Trying out the Striker II in the simulator. Latency is extremely low with no tearing, jittering or lag detectable in the symbology when moving the head fast. (BAE Systems)

More revolutionary, it also features a built-in night vision camera, that allows pilots to dispense with bulky NVGs. Not only are the NVGs cumbersome and awkward (and often force the pilot to chose between night vision/or symbology if a mission is at dawn or dusk) they also are extremely tiring. Wearing a NVG-equipped helmet with the equivalent of a ‘bag of sugar’ perched in front of your nose, means neck strain and fatigue – as well as increasing the risk of severe injury should the pilot have to eject. Says Mark Bowman, BAE Systems Director of Flight Operations: “It’s a 24/7 capability with a single helmet. I can have one helmet now and it is irrelevant to whether it is day or night.”

The digital interface now mean that the Striker II is future proofed for further updates – such as colour symbology or video. With digital inputs, picture in picture video, for example, could be fed into the helmet from on or offboard sensors. The Striker II HMD, paired with 360deg cameras (or even an in-built terrain database) could also enable a non-F-35 fighter pilot to enjoy a similar sort of situational awareness as a F-35 – by allowing the pilot to ‘look right through’ the aircraft‘s structure.

Another upgrade could see 3D positional audio integrated with the helmet – giving the pilot audio cues as to which direction, for example, a missile threat was coming from.

Leveraging gaming technology

A digital HMD opens up future HMI possibilties like this 'virtual/augmented reality' cockpit. Such a cockpit could be customised to the individual pilot or even the phase of flight. (BAE Systems)

Bowman also revealed that future enhancements of the Striker II could include Artificial Intelligence (AI) or further 3D augmented reality (AR) features. For example a ‘virtual cockpit’ could see (as in video games) weapons or defensive aid systems status icons ‘floating’ in virtual space – allowing the pilot to take in critical information merely by glancing down with eye tracking technology. “Its a powerful opportunity of converging gaming into how we can develop a future human machine interface (HMI).” As well as using eye-tracking to navigate large head-down displays, “If I could use eye tracking ‘head-out’ to open menu boxes, or manipulate data – how incredibly powerful is that?” adds Bowman.

Merging augmented reality too, with a digital HMD, could have training applications, allowing live/virtual synthetic training with pilots able to dogfight ‘virtual‘ bandits in visual range that are projected inside their helmet.

A digital HMD could conceivably be used as part of a future UAV/UCAV ‘cockpit’ ground control system allowing a ‘drone’ pilot to actually fly a UAV/UCAV as if they were sitting in it. Latency and bandwidth might be a challenge but it is worth remembering that some future concepts foresee UCAV wingmen being controlled by a manned fighter. Could a two-seat fighter in the ‘battlespace commander’ role see a rear WSO become a UCAV ‘pilot‘ flying the drone using a digital HMD?

Finally, it may one day be possible to incorporate ‘thought control‘ technology or neural sensors into the HMD to enhance situational awareness or flight safety (eg perhaps allowing the flight computer to take over if it had sensed the pilot had passed out due to G-LOC). Says Bowman on the future possibilities of Striker II: “Its limitless - it’s really where the technology wants to take you.”

BAE expect to finish flight testing of the Striker II by the ‘end of the second quarter of 2016’, according to Bowman. While the Striker II is yet to be ordered by any customer, the RAF‘s comprehensive Typhoon ‘Centurion’ upgrade, set for 2018 would seem a perfect time to phase in this new HMD front line pilots. Says Bowman: “I would want this technology now because it is the future and the sooner we can get it in the platform, the sooner we can take advantage of all that digital holds.” It is also worth noting that as an agnostic HMD, it could also find its way onto other platforms.

HUD evolution

The Blackburn Buccaneer was the first operational type to be fitted with a HUD. 

Rochester is also home of BAE’s HUD business – which can be traced back 50 years all the way to 1958 and the Strike Sight System for the Blackburn Buccaneer – the worlds first HUD in operational service. Since then, the company has supplied HUDs for 50 different aircraft – including the F-16, F-22 and C-17 and has delivered over 14,000 HUDs. It also provides the latest widescreen holographic HUD for the Eurofighter Typhoon.

Low-profile LiteHUD


View through the LiteHUD. Optical waveguide technology means it is 50% the weight of previous HUDs (BAE Systems).

Early HUDs, with bulky CRTs, have now given way to digital LED displays as used in projectors, which provide much higher levels of reliability. Yet while HUDs have ever wider fields of view (FoV) (the Typhoon is 30deg) the next trend is to address the form factor and space required for HUDs. Here BAE believe it is ahead of the game with its LiteHUD, a low-profile HUD that, while giving a 20deg FoV, is half the weight of a traditional display and 60% smaller in volume. The LiteHUD achieves this through novel optical waveguide technology – a proprietary IP from BAE. The waveguide technology also means that the pilot does not have to be ‘square-on‘ to see the symbology.

This means that for new aircraft (or even for retrofits or upgrades) cockpit design with the LiteHUD becomes less of a challenge as there is enough space for large-area displays below the HUD to be fitted in comfortably. While TextronAirLand demonstrated its new ScorpionJet at Farnborough 2014 with the LiteHUD sitting in their new aircraft, the first production aircraft to have selected the LiteHUD is Turkey‘s TAI Hürku-B basic trainer/light COIN aircraft.


Apex predator? The digital Striker II opens up  a 'limitless' upgrade path according to BAE. (BAE Systems) 

While HUDs and HMDs have spread from their original military roots to civil aviation, cars and even consumer augmented reality devices, there is no doubt that the combat pilot application, which requires ultra-demanding levels of precision, protection and reliability, represents the very apex of this technology. Furthermore, with the new digital Striker II HMD, BAE Systems has a product to ‘spiral in’ a number of innovative COTS technologies from sports science, medicine and video gaming. “The cornerstone for a HMI,” says Bowman “has to be a digital helmet display. We are now on a springboard, how do you now exploit it?”

11 March 2016