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An infra-red search and track (IRST) system (sometimes known as infra-red sighting and tracking) is a method for detecting and tracking objects which give off infrared radiation (see Infrared signature) such as jet aircraft and helicopters.〔Mahulikar, S.P., Sonawane, H.R., & Rao, G.A.: (2007) "Infrared signature studies of aerospace vehicles", ''Progress in Aerospace Sciences'', v. 43(7-8), pp. 218-245.〕 IRST is a generalized case of forward looking infrared (FLIR), i.e. from forward-looking to all-round situation awareness. Such systems are passive (thermographic camera), meaning they do not give out any radiation of their own, unlike radar. This gives them the advantage that they are difficult to detect. However, because the atmosphere attenuates infra-red to some extent (although not as much as visible light) and because adverse weather can attenuate it also (again, not as badly as visible systems), the range compared to a radar is limited. Angular resolution at short ranges is better than radar due to the shorter wavelength. == Early systems == The first use of an IRST system appears to be the F-101 Voodoo, F-102 Delta Dagger and F-106 Delta Dart interceptors. The F-106 had an early IRST mounting replaced in 1963 with a production retractable mount.〔Kinzey 1983, p. 12.〕 The IRST was also incorporated into the Vought F-8 Crusader (F-8E variant) which allowed passive tracking of heat emissions and was similar to the later Texas Instruments AAA-4 installed on early F-4 Phantoms.〔Sweetman 1987, p. 552.〕 The F-4 Phantom had a Texas Instruments AAA-4 infrared seeker〔Sweetman 1987, p. 526.〕 under the nose of early production aircraft F-4B's and F-4C's and not installed on later F-4-D's due to limited capabilities,〔Sweetman 1987, p. 532.〕 but retained the bulge and indeed some F-4D's had the IRST receiver retrofitted in a modified form.〔Sweetman 1987, p. 552.〕 The F-4E eliminated the AAA-4 IRST bulge and received an internal gun mount which took up the area under the nose.〔Sweetman 1987, p. 537.〕 The F-4J also eliminated the AAA-4 IRST receiver and bulge under the nose.〔Eden 2004, p. 279.〕 The Swedish Saab J-35F2 Draken (1965) also used an IRST, a Hughes Aircraft Company N71. 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「Infra-red search and track」の詳細全文を読む スポンサード リンク
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