page_title: Infrared homing
section_title: Later designs
hierarchical_section_title: Infrared homing / History / Later designs
caption_attribution_description: English: Mockup of SRAAM missile on display at RAF Museum Cosford
context_page_description: Infrared homing is a passive weapon guidance system which uses the infrared light emission from a target to track and follow it. Missiles which use infrared seeking are often referred to as "heat-seekers" since infrared is radiated strongly by hot bodies. Many objects such as people, vehicle engines and aircraft generate and emit heat and so are especially visible in the infrared wavelengths of light compared to objects in the background.
  Infrared seekers are passive devices, which, unlike radar, provide no indication that they are tracking a target. That makes them suitable for sneak attacks during visual encounters or over longer ranges when they are used with a forward looking infrared or similar cuing system. Heat-seekers are extremely effective: 90% of all United States air combat losses over the past 25 years have been caused by infrared-homing missiles. They are, however, subject to a number of simple countermeasures, most notably by dropping flares behind the target to provide false heat sources. That works only if the pilot is aware of the missile and deploys the countermeasures, and the sophistication of modern seekers has rendered them increasingly ineffective.
context_section_description: As Vietnam revealed the terrible performance of existing missile designs, a number of efforts began to address them. In the US, minor upgrades to the Sidewinder were carried out as soon as possible, but more broadly pilots were taught proper engagement techniques so they would not fire as soon as they heard the missile tone, and would instead move to a position where the missile would be able to continue tracking even after launch. This problem also led to efforts to make new missiles that would hit their targets even if launched under these less-than-ideal positions. In the UK this led to the SRAAM project, which was ultimately the victim of continually changing requirements. Two US programmes, AIM-82 and AIM-95 Agile, met similar fates.
  New seeker designs began to appear during the 1970s and led to a series of more advanced missiles. A major upgrade to the Sidewinder began, providing it with a seeker that was sensitive enough to track from any angle, giving the missile all aspect capability for the first time. This was combined with a new scanning pattern that helped reject confusing sources (like the sun reflecting off clouds) and improve the guidance towards the target. A small number of the resulting L models were rushed to the UK just prior to their engagement in the Falklands War, where they achieved an 82% kill ratio, and the misses were generally due to the target aircraft flying out of range. The Argentine aircraft, equipped with Sidewinder B and R.550 Magic, could only fire from the rear aspect, which the British pilots simply avoided by always flying directly at them. The L was so effective that aircraft hurried to add flare countermeasures, which led to another minor upgrade to the M model to better reject flares. The L and M models would go on to be the backbone of western air forces through the end of the Cold War era.
  An even larger step was taken by the Soviets with their R-73, which replaced the K-13 and others with a dramatically improved design. This missile introduced the ability to be fired at targets completely out of view of the seeker; after firing the missile would orient itself in the direction indicated by the launcher and then attempt to lock on. When combined with a helmet mounted sight, the missile could be cued and targeted without the launch aircraft first having to point itself at the target. This proved to offer significant advantages in combat, and caused great concern for western forces.
  The solution to the R-73 problem was initially going to be the ASRAAM, a pan-European design that combined the performance of the R-73 with an imaging seeker. In a wide-ranging agreement, the US agreed to adopt ASRAAM for their new short-range missile, while the Europeans would adopt AMRAAM as their medium-range weapon. However, ASRAAM soon ran into intractable delays as each of the member countries decided a different performance metric was more important. The US eventually bowed out of the program, and instead adapted the new seekers developed for ASRAAM on yet another version of the Sidewinder, the AIM-9X. This so extends its lifetime that it will have been in service for almost a century when the current aircraft leave service. ASRAAM did, eventually, deliver a missile that has been adopted by a number of European forces and many of the same technologies have appeared in the Chinese PL-10 and Israeli Python-5.
caption: SRAAM was designed to address most of the problems found with earlier IR missiles in a very short-range weapon.
exif: {"Image Make": "FUJIFILM", "Image Model": "FinePix S5000", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Digital Camera FinePix S5000 Ver3.00", "Image DateTime": "2010:11:15 16:37:20", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "5120", "Thumbnail ImageWidth": "200", "Thumbnail ImageLength": "101", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail JPEGInterchangeFormat": "242", "Thumbnail JPEGInterchangeFormatLength": "4739", "EXIF ExposureTime": "1", "EXIF FNumber": "28/5", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "400", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2010:11:15 16:37:20", "EXIF DateTimeDigitized": "2010:11:15 16:37:20", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "2", "EXIF ShutterSpeedValue": "0", "EXIF ApertureValue": "5", "EXIF BrightnessValue": "-139/100", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "15/2", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1614", "EXIF ExifImageLength": "816", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "5546", "EXIF FocalPlaneXResolution": "3827", "EXIF FocalPlaneYResolution": "3827", "EXIF FocalPlaneResolutionUnit": "3", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Manual", "EXIF SceneCaptureType": "Standard", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0"}