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Anti-aircraft warfare or counter-air defence is defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action."〔AAP-6〕 They include ground-and air-based weapon systems, associated sensor systems, command and control arrangements and passive measures (e.g. barrage balloons). It may be used to protect naval, ground, and air forces in any location. However, for most countries the main effort has tended to be 'homeland defence'. NATO refers to airborne air defence as counter-air and naval air defence as anti-aircraft warfare. Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting any projectile in flight. In some countries, such as Britain and Germany during the Second World War, the Soviet Union and NATO's Allied Command Europe, ground based air defence and air defence aircraft have been under integrated command and control. However, while overall air defence may be for homeland defence including military facilities, forces in the field, wherever they are, invariably deploy their own air defence capability if there is an air threat. A surface-based air defence capability can also be deployed offensively to deny the use of airspace to an opponent. Until the 1950s, guns firing ballistic munitions ranging from 20 mm to 150 mm were the standard weapon; guided missiles then became dominant, except at the very shortest ranges (as with close-in weapon systems, which use rotary autocannons). == Terminology == The term ''air defence'' was probably first used by Britain when Air Defence of Great Britain (ADGB) was created as a Royal Air Force command in 1925. However, arrangements in the UK were also called 'anti-aircraft', abbreviated as AA, a term that remained in general use into the 1950s. After the First World War it was sometimes prefixed by 'Light' or 'Heavy' (LAA or HAA) to classify a type of gun or unit. Nicknames for anti-aircraft guns include AA, AAA or triple-A, an abbreviation of anti-aircraft artillery; "ack-ack" (from the spelling alphabet used by the British for voice transmission of "AA");〔("ack-ack, adj. and n.". ) OED Online. September 2013. Oxford University Press. (accessed September 14, 2013).〕 and archie (a World War I British term probably coined by Amyas Borton and believed to derive via the Royal Flying Corps from the music-hall comedian George Robey's line "Archibald, certainly not!"). NATO defines anti-aircraft warfare (AAW) as "measures taken to defend a maritime force against attacks by airborne weapons launched from aircraft, ships, submarines and land-based sites."〔.AAP-6〕 In some armies the term All-Arms Air Defence (AAAD) is used for air defence by non-specialist troops. Other terms from the late 20th century include GBAD (Ground Based AD) with related terms SHORAD (Short Range AD) and MANPADS ("Man Portable AD Systems": typically shoulder-launched missiles). Anti-aircraft missiles are variously called surface-to-air missile, abbreviated and pronounced "SAM" and Surface to Air Guided Weapon (SAGW). Non-English terms for air defence include the German ''Flak'' (Fliegerabwehrkanone, "aircraft defence cannon",〔(【引用サイトリンク】flak )〕 also cited as ''Flugabwehrkanone''), whence English flak, and the Russian term Protivovozdushnaya oborona (Cyrillic: Противовозду́шная оборо́на), a literal translation of "anti-air defence", abbreviated as PVO.〔Bellamy pg 219〕 In Russian the AA systems are called ''zenitnye'' (i.e. "pointing to zenith") systems (guns, missiles etc.). In French, air defence is called DCA (''Défense contre les aéronefs'', "aéronef" being the generic term for all kind of airborne device (airplane, airship, balloon, missile, rocket, etc.)).〔le petit Larousse 2013 p20-p306〕 The maximum distance at which a gun or missile can engage an aircraft is an important figure. However, many different definitions are used but unless the same definition is used, performance of different guns or missiles cannot be compared. For AA guns only the ascending part of the trajectory can be usefully used. One term is 'ceiling', maximum ceiling being the height a projectile would reach if fired vertically, not practically useful in itself as few AA guns are able to fire vertically, and maximum fuse duration may be too short, but potentially useful as a standard to compare different weapons. The British adopted "effective ceiling", meaning the altitude at which a gun could deliver a series of shells against a moving target; this could be constrained by maximum fuse running time as well as the gun's capability. By the late 1930s the British definition was "that height at which a directly approaching target at 400 mph ''(=643.6 km/h)'' can be engaged for 20 seconds before the gun reaches 70 degrees elevation".〔Hogg WW2 pg 99–100〕 However, effective ceiling for heavy AA guns was affected by non-ballistic factors: * The maximum running time of the fuse, this set the maximum usable time of flight. * The capability of fire control instruments to determine target height at long range. * The precision of the cyclic rate of fire, the fuse length had to be calculated and set for where the target would be at the time of flight after firing, to do this meant knowing exactly when the round would fire. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Anti-aircraft warfare」の詳細全文を読む スポンサード リンク
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