Active radar homing (ARH) is a missile guidance method in which a missile contains a radar transceiver (in contrast to semi-active radar homing, which uses only a receiver) and the electronics necessary for it to find and track its target autonomously.
The NATO brevity code for an air-to-air active radar homing missile launch is Fox Three.
Brimstone is a ground or air-launched ground attack missile developed by MBDA UK for the UK's Royal Air Force. It was originally intended for "fire-and-forget" use against mass formations of enemy armour, using a millimetre wave (mmW) active radar homing seeker to ensure accuracy even against moving targets. Experience in Afghanistan led to the addition of laser guidance in the dual-mode Brimstone missile, allowing a "spotter" to pick out specific and the highest priority targets, particularly useful to minimise collateral damage when friendly forces or civilians were in the area. The tandem shaped-charge warhead is much more effective against modern tanks than older similar weapons such as the AGM-65G Maverick missile. Three Brimstones are carried on a launcher that occupies a single weapon station, allowing a single aircraft to carry many missiles.
After a protracted development programme, single-mode or "millimetric" Brimstone entered service with RAF Tornado aircraft in 2005, and the dual-mode variant in 2008. The latter was used extensively in Afghanistan and Libya. An improved Brimstone 2 was expected to enter service in October 2012, but problems with the new warhead from TDW and the ROXEL rocket motor put back the planned date to November 2015. MBDA is studying the use of Brimstone on ships, attack helicopters, UAVs, and from surface launchers. However, it will not be integrated on the Lockheed Martin F-35 Lightning II. Germany, Qatar and Saudi Arabia have purchased the missile. The cost per missile has been quoted as £175,000 each in 2015, or "over £100,000".
An air-to-surface missile (ASM) or air-to-ground missile (AGM) is a missile designed to be launched from military aircraft at targets on land or sea. There are also unpowered guided glide bombs not considered missiles. The two most common propulsion systems for air-to-surface missiles are rocket motors, usually with shorter range, and slower, longer-range jet engines. Some Soviet-designed air-to-surface missiles are powered by ramjets, giving them both long range and high speed.
Guidance for air-to-surface missiles is typically via laser guidance, infrared guidance, optical guidance or via satellite guidance signals. The type of guidance depends on the type of target. Ships, for example, may be detected via passive radar or active radar homing, which is less effective against multiple, small, fast-moving land targets.
An anti-ship missile (AShM or ASM) is a guided missile that is designed for use against ships and large boats. Most anti-ship missiles are of the sea-skimming variety, and many use a combination of inertial guidance and active radar homing. A large number of other anti-ship missiles use infrared homing to follow the heat that is emitted by a ship; it is also possible for anti-ship missiles to be guided by radio command all the way.
Many anti-ship missiles can be launched from a variety of weapons systems including surface warships (also referred to as ship-to-ship missiles), submarines, bombers, fighter planes, patrol planes, helicopters, shore batteries, land vehicles, and, conceivably, even infantrymen firing shoulder-launched missiles. The term surface-to-surface missile (SSM) is used when appropriate. The longer-range anti-ship missiles are often called anti-ship cruise missiles. Several countries are also developing anti-ship ballistic missiles.
Fire-and-forget is a type of missile guidance which does not require further external intervention after launch such as illumination of the target or wire guidance, and can hit its target without the launcher being in line-of-sight of the target. This is an important property for a guided weapon to have, since a person or vehicle that lingers near the target to guide the missile (using, for instance, a laser designator) is vulnerable to attack and unable to carry out other tasks.
Generally, information about the target is programmed into the missile just prior to launch. This can include coordinates, radar measurements (including velocity), or an infrared image of the target. After it is fired, the missile guides itself by some combination of gyroscopes and accelerometers, GPS, onboard active radar homing, infrared homing optics, and anti-radiation homing. Some systems offer the option of either continued input from the launch platform or fire-and-forget.