Battlefield illumination



From a military standpoint, lighting has long been recognised as a critical part of the battlefield conditions. Shadows are good places to hide, while bright areas are more exposed. It is often beneficial to fight with the Sun or other light source behind you, giving your enemy disturbing visual glare and partially hiding your own movements in backlight. If natural light is not present searchlights, whether using visible light or infrared, and flares can be used.



Light may disclose the user's own position. Modern warfare has accordingly seen increased use of night vision through the use of infrared cameras and image intensifiers.



Flares can be used to mark positions, usually for targeting, but laser-guided and GPS weapons have reduced this function. GPS-guided bombs, for example, rely only on GPS signals, without any locally-provided target designation. Laser-guided bombs require a laser designator to guide them to the target, in turn requiring an observer (in the aircraft or on the ground) able to see the target and aim the laser designator.

Adverse weather such as fog, rain and snow reduce both visibility and the usefulness of illumination. Enemy action in the form of smoke and shellfire, and the dust and smoke created by battle generally, further limit the effectiveness of illumination. Thermal imaging devices (using infrared) can however to some extent penetrate these obstacles.

History


The Canal Defence Light was a British "secret weapon" of the Second World War. It was a tank fitted with a powerful carbon-arc searchlight to support night-time attacks. The War Office ordered 300 such lamps in 1940.

Target indicator flares were widely used by the Royal Air Force during the Second World War; these were dropped by a wave of Pathfinder Force aircraft ahead of the main force of bombers to indicate the aiming point.