Infrared aiming system
An infrared target system ( English infra-red search and track , IRST ) is a military device that is mostly installed on combat aircraft with the task of discovering and tracking objects emitting infrared radiation (e.g. aircraft and helicopters).
The infrared aiming system works with Forward Looking Infrared (FLIR) technology ( thermal imaging camera ). It works completely passively, which means that it does not emit any electromagnetic radiation. This enables the system to capture a target unnoticed and to attack with infrared guided missiles. With radar-based fire control, this is only possible with a great deal of effort due to the widespread use of radar warning systems , which detect the radar radiation that is inevitably emitted with this method and can even localize its source ( LPI ). In addition, due to their passive nature, FLIR systems are completely immune to electronic countermeasures . Another advantage over traditional radars is their relatively small size and lower energy consumption.
However, the considerable weather dependency of the infrared radiation has a disadvantageous effect. In particular, water vapor, which is concentrated near the ground and especially in clouds of all kinds, can reduce the range of an IRST system many times over. In addition, the range of an infrared system, even under good conditions (sensor and target fly at high altitude with little atmospheric water vapor), is usually considerably less than that of a radar system with a similar technical level. Furthermore, in comparison to a radar, an IRST system cannot directly determine the distance, speed or size of a detected contact, but can only determine the direction relative to the sensor. Only through time-consuming long-term observation, favorable flight directions and data links with other IRST systems in the vicinity can these parameters be determined precisely enough after a while to be able to use guided weapons effectively. The effort for such a determination is greater, the further away the target is. Since most FLIR systems are mounted as an external container or just in front of the cockpit window, they also have a more restricted viewing angle than the radar that is usually mounted in the tip of the aircraft , as this is largely covered by the aircraft fuselage.
Due to these properties, airborne IRST systems are usually only suitable for the reliable use of weapons over relatively short distances and act more as an early warning sensor over medium to long distances. In addition, it is a useful addition to typical radar systems, especially for targets with advanced radar stealth technology and strong electronic countermeasures, as their effectiveness is greatly reduced under such conditions. Newer all-round IRST systems (e.g. AAQ-37 DAS ) can, in addition to the traditional detection of other aircraft, also detect a large number of other heat events such as the firing of ( flak ) cannons or ( SAM ) missiles as well as approaching guided weapons. In addition, they can serve as a replacement for night vision devices.
Ground-based IRST systems are relatively rare because the relatively high humidity and frequent cloud cover massively reduce the range. In this context, if at all, they are only used for short to very short distances as a secondary aid for the radar.
literature
- Eden, Paul ed. The Encyclopedia of Modern Military Aircraft . London: Amber Books Ltd, 2004. ISBN 1-904687-84-9
- Kinzey, Bert. F-106 Delta Dart, in Detail & Scale . Fallbrook, CA: Aero Publishers, 1983. ISBN 0-8168-5027-5 .
- Sweetman, Bill and Bonds, Ray. The Great Book of Modern Warplanes . New York, New York: Crown Publishers, 1987. ISBN 0-517-63367-1
Web links
Individual evidence
- ↑ Mahulikar, SP, Sonawane, HR, & Rao, GA: (2007) "Infrared signature studies of aerospace vehicles", Progress in Aerospace Sciences , v. 43 (7-8) , pp. 218-245.