There’s a whole range of sophisticated night vision equipment available to police, paramilitary and security organisations. But one reliable passive light system has existed for thousands of years – the good old Mk I eyeball.
Combined with good hearing and a sense of smell, human eyesight can be used to penetrate darkness. With the assistance of simple equipment like binoculars, it can gather enough light to see objects that would otherwise be ill-defined in the dark. For many years, these senses, along with active light sources like flares and electric light, were all that were available for night operations.
At the close of World War II, active infra-red (IR) had entered service. With it, a driver could illuminate the road with lights fitted with an IR filter, and see it through special binoculars. Fitted to a rifle, the system could also be used for medium range sniping.
Unfortunately it could also be seen by anyone wearing similar binoculars, and even by men wearing the next generation of night viewing equipment – Image Intensification or II. It was easy to trace the source of the IR beam – it looks like a powerful torch beam.
Image Intensification is a passive system that amplifies the ambient light from man made and natural sources including the moon and stars – which gave it the nickname the Starlight Scope in US military service during the 1962-75 Vietnam War. One of the attractions of II is that it can be upgraded simply by adding extra lenses at the front – rather like adding a telephoto lens to a camera.
The Pilkington Kite Observation Sight, or KOS, is in British Army service as the Common Weapons Sight or CWS (pictured at top of page). It can be upgraded from 4x to 6x magnification by adding an extra lens at the front. This allows a soldier to recognise a standing man at a range of 450 metres in starlight conditions. Other modifications to Kite include Binokite (pictured alongside), which has a 4.5x magnification and, with its two eyepieces, is easier to use. Significantly, these Pilkington systems use commercially available 1.5V AA batteries.
II equipment has improved enormously since the 1960s, and its weight has been reduced. The EEV Nite Watch Plus II viewer, for instance, is only 46mm in diameter, 120mm long, and weighs just 330g with lens and batteries. It can be used in a simple hand-held mode, or fitted to an SLR camera, CCTV or video.
Reliability has been enhanced through three generations of II equipment. ‘Second Gen’ II equipment has improved light intensification up to 20,000 times, compared to 1,000 times in ‘First Gen’ equipment. Filtration is incorporated so that Second Gen kit does not ‘bloom out’ if the user points it at a light source such as car headlights. Blooming out fogs the screen by producing a temporary after-image.
‘Third Gen’ is an improvement on second, with better filters, but the enhancement is relatively small for the increase in cost, making it unattractive to all but government agencies.
Litton Elecronic Devices of Tempe, Arizona, have a wide range of Second and Third Gen equipment, including goggles and monoculars for aircrew, AFV drivers and, interestingly, scuba divers.
Passive Night Goggles (PNGs) were first used operationally by British helicopter crews in the Falklands War of 1982, to insert special forces by night onto the island.
The end of the Cold War released a huge range of low cost Russian made II equipment onto the market, including binoculars and hand-held systems with IR illumination. First Gen systems such as the T3C2 can now be bought for as little as £100, and this has led to the use of II equipment by criminals and terrorists. II can be extremely useful in planning and carrying out a criminal or terrorist attack. One way to combat this new threat is to ensure that vulnerable buildings and installations are screened from view by fences, walls or vegetation.
Though criminals and terrorists may have access to II, unless they are sponsored by state oranisations they are unlikely to have Thermal Imaging (TI) equipment. TI presents a picture showing the different heat patterns produced by men, machines and other objects, whether natural or man-made.
TI allows operators to see through visual camouflage and smoke, so a vehicle screened by a net or vegetation would show up warm through the cover. TI is extremely useful in search and rescue operations, since operators can find survivors in dense cover or smoky rooms. They can also locate small heat sources, such as a liferaft in the open sea, or a live body in an expanse of snowy hillside.
TI was first used by the British Army operationally in the Falklands in 1982, where the heat ‘signature’ of sheep roaming across the moorland cause some confusion for operators! TI can be used by day as well as by night, without special filters.
As with II, TI equipment has been made much smaller than the early bulky systems. Modern TI equipment is no more bulky than a video camcorder. A good example is the GEC Marconi Pyro 2000. This battery powered unit weighs 1.5kg excluding the lens and battery pack. It is 200mm long, 75mm high, and 140mm wide.
The Thorn EMI Electronics Lite can be fitted with a variety of lenses and is cooled by a microcooler or air bottle, which means that weights range from 3.4kg to 5.6kg. Lite can be used as a hand-held system, fitted to weapons such as machine guns, or used as a tracker for anti-aircraft or anti-tank missile firing posts.
TI is enormously useful, but it does have its limitations. It doesn’t perform well in rain or sand storms for instance. The picture it produces at medium and short ranges is clear, but at longer ranges the operator sees just a warm ‘blob’. In the Gulf War of 1991, this led to some of the ‘blue on blue’ or friendly fire casualties.
TI was literally a life-saver during the Gulf War, however. With no ambient light on a cloudy night in the desert, II equipment is useless. Only HHTI (hand-held thermal imaging) equipment allowed soldiers to locate Iraqi positions.
The cost of night vision equipment has fallen since the 1960s, along with its weight and bulk, while the quality and versatility have improved considerably. The various night vision devices open up new possibilities for fighting at night, but it can only be used effectively if the soliders using it also make good use of the night vision equipment they were born with – eyes, ears, nose, and a suspicious mind!