Infra-red search and track
（重定向自IRST）
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.
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.
![An IRST sensor on the Su-27.](/Images/godic/202501/21/Su-27UB_cockpit1846.jpg")
![An F-8E of VMF(AW)-235 at Da Nang, in April 1966 showing the IRST in front of the canopy.](/Images/godic/202501/21/F-8E_VMFAW-235_DaNang_Apr19661847.jpg")
![Optronique secteur frontal (IRST) of the Dassault Rafale, below the cockpit and to the side of the refueling boom. On the left, the main IR sensor (100 km range), on the right a TV/IR identification sensor with laser rangefinder (40 km range)](/Images/godic/202501/21/Rafale_B_at_Paris_Air_Show_20071847.jpg")
![Eurofighter Typhoon with PIRATE IRST](/Images/godic/202501/21/RAF_Typhoon_Prepares_for_Takeoff_from_Italy_on_Libyan_Mission_MOD_451528431847.jpg")