A stab in the dark

According to a report from the research company Markets and Markets, the NVD (night vision device market) is projected to exceed $7.73 billion by 2020, rising at a CAGR of 8.8% from its 2015 value of $5.07 billion. Some estimates put its future worth even higher than that, with defence purchases tipped to boom as countries ramp up their modernisation programmes and increase their surveillance capabilities in the wake of ongoing conflicts and growing geopolitical uncertainty. 80 years on from Germany’s first experiments with so-called ‘generation-zero’ (Gen-0) technology, night vision has come of age and no army can be without it.

Early beginnings: the ‘Vampir’ of the Eastern Front

When those first systems were introduced in 1939, the limitations of the then-fledgling field of electro-optics technology meant that the new devices were big and cumbersome. The earliest versions often depended on huge, vehicle-mounted infrared searchlights to provide the necessary invisible illumination, making them useful as night sights on tanks, but severely restricting their value to infantry.

As the war progressed, Gen-0 advancements in Germany, the UK, the US and Russia increasingly began to overcome those limitations, with some notable successes recorded, particularly as the conflict drew towards its close. On the Eastern Front, veterans spoke of night snipers using “peculiar non-shining torches coupled with enormous optical sights” – the ‘Vampir’ NVD developed for the Sturmgewehr 44 assault rifle.

The improved technology came too late to change the course of the war for the Third Reich, but its performance in the Pacific may have gone a long way to establishing the value of night vision capability, and ensuring it remained a major priority for research. In the opening week of Operation Iceberg, as the US forces fought to retake Okinawa, the infrared ‘sniper scope’ is said to have been instrumental in some 30% of the total Japanese casualties that fell to small-arms fire – a remarkable tally given that only around 500 of them were issued at the time.

Going passive with ‘Starlight’ and Gen-1

Active infrared technology remained the mainstay after the Second World War with the likes of the sniper scope, by then the 4th model of the Mark-3 version, seeing service throughout the Korean War, and the AN/PAS-4 subsequently deployed during the early years of the Vietnam conflict. By 1961 however, a major breakthrough paved the way for the next step in night vision, and the next generation of devices soon followed.

Gen-1 introduced passive, image intensifying systems such as the US AN/PVS-1 ‘Starlight’ and the Soviet Union’s NSPU 1PN34 rifle sights. Freed from the need to illuminate the darkness actively, the new scopes worked on available ambient light, using significantly improved photocathode technology to intensify and amplify it by around 1,000-fold. The earliest versions were particularly bulky, and required good moonlight to function at their best, which was an obvious problem on moonless nights of the month or when under cloudy skies.

Capability step-change: Gen-2’s enhanced image intensification

Extensive development followed to reduce the weight and improve the performance and reliability. By the closing days of the Vietnam War, new image-intensifying technology was to emerge that enabled the jump to Gen-2, and the kind of superior capability that General McCaffrey enjoyed in Kuwait and Iraq.

Second-generation devices provided a real step change, with enhanced image intensification thanks to the combination of the new micro-channel plate (MCP) and upgraded S-25 photocathode. Providing light amplification in the region of 20,000 times, the resulting high-quality image was considerably brighter than with Gen-1 devices, and almost entirely free of distortion.

This period saw the start of a huge proliferation of technologies and systems in the sector, as breakthroughs in thermal imaging enabled soldiers to ‘see’ the heat emissions from people and objects, even in complete darkness, and night vision technology reached beyond rifle sights to spawn other kinds of devices, most notably night vision goggles (NVGs).

Subsequent developments in Gen-2 optics, image resolution and signal-tonoise ratios saw the arrival of further enhanced devices – referred to as ‘Gen-2+’ – before true thirdgeneration systems finally appeared.

Mixed blessing: Gen-3’s ion barrier film and gallium arsenide photocathode

In some ways, the move to Gen-3 came as a bit of a mixed blessing. These systems retain Gen-2’s MCP, coating it with an ion barrier film to prolong tube life and replace the S-25 photocathode with one made from gallium arsenide (GaAs).

In theory, this GaAs photocathode should significantly improve image resolution, but in practice, the gain has been muted because the ion film reduces the number of the electrons passing through, and additionally increases the halo-effect seen around bright light sources. Gen-3 tubes demand more power than their Gen-2 equivalents, although on the plus-side, they can achieve two-and-a-half times greater light amplification.

To address the shortcomings, devices were developed that either greatly reduced the ion barrier, or omitted it entirely and added an automatic gated power supply system to regulate the photocathode’s voltage, thus enabling it to adapt to changing light conditions instantly. Known as Gen-4 in some markets, and to the US military as Gen-3 Auto-gated tubes, these systems bring unparalleled light sensitivity and operational performance – but they are certainly not the end of the story.

Future possibilities: bringing forward-looking infrared to soldiers in the field

A range of new possibilities are waiting. Advances in long and short-wave infrared technology could bring the kind of forward-looking infrared capability currently only really seen on aircraft and vehicles, to soldiers in the field, while complementary metal oxide semiconductor and electron bombarded active pixel sensors promise new levels of low-light imaging clarity.

Future devices are likely to show a strong trend towards incorporating such multiple, stand-alone capabilities into a single unit, and additionally a high level of integration between individual NVDs themselves, allowing, for example, soldiers to use their gunsights to take a clandestine look around corners. Going even further, other technologies too can be expected to play more of a role, including eye-tracking, tactical overlays and the inclusion of microelectro-optics to overcome the severely narrowed field of view – perhaps as little as 40° – of current designs, compared with around 165° of normal human vision. The familiar ghostly green hue of night vision might disappear with the possible wider introduction of multicolour image rendition.

Enhancing for rapid target acquisition and significantly greater situational awareness NVGs in particular seem poised to see some of the biggest changes. This is due to the trend towards reducing their size, weight and power demand continuing, and unit prices dropping, favouring the growth of enhanced night vision goggle (ENVG) technology.

The fusion of thermal imaging and image intensification into a single device makes for rapid target acquisition and significantly greater situational awareness, as systems now being developed can highlight the outline of an individual soldier against the background of its surroundings.

Additional benefits: subsidiary technologies and stylistic choices for current innovations

In addition to improving threat detection and identification in all operating conditions, including total darkness, ENGVs are set to become shorter, reducing forward protrusion by perhaps as much as 3–4in, as attention focuses on the form, fit and extended wearability of the devices too.

In future, ENVGs may have super-zoom facilities, allowing a small area of view to be examined in closer detail, and be able to transfer data seamlessly with other elements of a secure battlefield network.

Looking even further ahead, advances in sensor technology such as the super-thin graphemebased infrared light sensor recently devised by researchers at the University of Michigan could ultimately see NVGs looking more like Ray-Bans or even in the form of contact lenses. Night vision still promises to have a long way to go.