page_title: Contrast seeker
section_title: Examples
hierarchical_section_title: Contrast seeker / Examples
caption_attribution_description: AGM-65 moments before impacting on an M-48 tank.
context_page_description: Optical contrast seekers, or simply contrast seekers, are a type of missile guidance system using a television camera as its primary input. The camera is initially pointed at a target and then locked on, allowing the missile to fly to its target by keeping the image stable within the camera's field of view.
  The first production missile to use a contrast seeker was the AGM-65 Maverick, which began development in the 1960s and entered service in 1972. The system has not been widely used, as other guidance technologies like laser guidance and GPS have become more common, but the same basic concept is used in cameras to track objects, including the systems used to aim the laser designators.
  Contrast seekers should be distinguished from television guidance systems, in which a live television signal is broadcast to the launch platform, which then uses manual direction to attack the target. Examples of TV guidance include the Martel and AGM-62 Walleye. The term "contrast contour" is sometimes used, but this may be confused with TERCOM systems.
context_section_description: The basic concept has been used in various forms since the 1940s. On the earliest examples is the Aeronca GB-5 (GB for Glide Bomb) which was intended as an anti-shipping system. This was essentially a bomb equipped with short straight wings and small tail surfaces with a tracking system from Hammond-Crosley called the B-1. Unlike later examples, this used a mechanical scanning system, with two photocells examining changes in contrast as the seeker oscillated left and right. This worked well against ships, where the ship was the only thing breaking the horizon line. This was one of many different tracking systems carried out as part of the GB series, which also included television guidance, semi-active radar homing, infrared homing and any number of different MCLOS radio control systems.
  The best-known example of a contrast seeking missile is the Maverick, which has been in continual use since the early 1970s. In some early combat uses in the Vietnam War, pilots on their very first mission "vaporized" a truck with a direct hit, only to be admonished by their commanding officer for using a $25,000 weapon against a $500 target. In spite of this, the pilots were extremely enthusiastic about the weapon and it became a staple of the USAF during the 1970s. In total, 99 missiles were fired during the Linebacker raids in 1972, achieving an 88% hit rate.
  Starting in 1967, the same basic seeker was also adapted as the basis for the Homing Bomb System, or HOBOS, which was a guidance package fit to a standard 2,000 pounds (910 kg) Mark 84 bomb. The guidance systems, the KMU-353 and KMU-390, were essentially re-packaged Maverick A-model seekers, while the KMU-359/B used the later IR imager version from the D-model Mavericks. When completely assembled, the seeker, guidance system and bomb were known as the GBU-8, or GBU-9 when used with the 3,000 pounds (1,400 kg) Mark 118 bomb. An update program started in 1972 to address concerns about lock-on range, resulting in the GBU-15. This differed primarily in that it sent the image back to the launch aircraft while the missile was in flight, allowing the weapon officer to correct its trajectory in a fashion more similar to other television guided systems.
  A major problem discovered by the crews in early testing was that the image was often too small to lock onto from long range, requiring an approach to distances well into the missile's range. On other occasions the missile would lock onto nearby targets, in one case breaking off from a tank to land in a bush, which the crew quickly christened a "tactical bush". The use of videotape of the seeker's target allowed new crews to learn from their experience and quickly learn what sort of targets and encounters would lead to successes.
  The contrast seeker had a number of operational problems as well. Because of the environment they flew in, contrast seekers were generally not suitable to launch from helicopters, which led to experiments using wire guidance (TOW) or laser homing (Hellfire). Ultimately these systems proved suitable for launch from many types of platforms, and laser guidance in particular has become more widespread. These systems, however, often use the same basic tracking system as part of the laser designator system on the aircraft, keeping the camera or FLIR roughly pointed at the locked target in the same way it worked in the missile seeker.
caption: In service, Maverick demonstrated an average miss distance of only four feet from the aim point.
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