Predicted fire (originally called ''map shooting'') is a tactical technique for the use of

artillery Artillery consists of ranged weapons that launch Ammunition, munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and l ...

, enabling it to fire for effect without alerting the enemy with ranging shots or a lengthy preliminary bombardment. The guns are laid using detailed calculations and surveys to increase aiming accuracy from the first round.

Field artillery

Predicted fire aims to achieve tactical surprise when the target is to be engaged by

indirect fire Indirect fire is aiming and firing a projectile without relying on a direct line of sight between the gun and its target, as in the case of direct fire. Aiming is performed by calculating azimuth and inclination, and may include correcting ...

. Gun laying is based on calculations of the range and

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

of the target relative to the gun position, without the need for ranging shots (or ''adjusting'') or even observation of the target. Ranging shots take time, and alert the enemy both to the presence and position of the guns, and to the likelihood of an attack. Predicted fire enables enemy artillery, strongpoints or troop concentrations to be struck without warning, often shortly before a friendly attack so as to leave no time for recovery, or engagement of targets hidden from observation by friendly forces. It can be used to plan any type of fire, including concentrations or the creeping barrages commonly used in

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

.Hogg, p 32 Predicted fire was developed during World War I and became the main method of using

field artillery Field artillery is a category of mobile artillery used to support army, armies in the field. These weapons are specialized for mobility, tactical proficiency, short range, long range, and extremely long range target engagement. Until the ear ...

until the present day. The first battle in which the fireplan consisted entirely of predicted fire was the Battle of Cambrai in 1917, in which the British guns were moved into surveyed positions at the last moment, achieving tactical surprise when they commenced firing. Predicted fire requires precise surveying of the gun position and accurate maps. Ideally all firing batteries will have been surveyed onto a common survey grid. Accurate shooting needs complicated calculations including such factors as the elevation of the target and firing position, wind speed and direction, barometric pressure, gun barrel wear and even propellant batch and temperature. The opposite of prediction is ''reduction'', the process of calculating a target's map co-ordinates for a target registered by firing. Glossary of Royal Artillery terminology in World War 2

Anti-aircraft warfare

Predicted fire is also used by anti-aircraft guns, using a device called a ''predictor'' or ''director'' to compute a firing solution.

Footnotes

References

* Hogg, Ian V, Barrage: the Guns in Action, Macdonald, 1971 * {{cite web , url=http://nigelef.tripod.com/index.htm , title=Artillery in World War 2—The field artillery organisation, tactics, gunnery methods and regiments of the Royal Artillery and the artilleries of British Commonwealth , accessdate=2 January 2010 A large and detailed site on Royal Artillery methods in World War 2 Artillery operation