The AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM) is a modern American beyond-visual-range air-to-air missile (BVRAAM) capable of all-weather day-and-night operations. Designed with a 7-inch diameter form-and-fit factor, and employing active transmit-receive radar guidance instead of semi-active receive-only radar guidance, it has the advantage of being a fire-and-forget weapon when compared to the previous generation Sparrow missiles. When an AMRAAM missile is launched, NATO pilots use the brevity code Fox Three. The AMRAAM is the world’s most popular beyond-visual-range missile, and more than 14,000 have been produced for the United States Air Force, the United States Navy. Procured by 37 countries including the U.S., the combat-proven AMRAAM missile has been integrated onto the F-15, F-16, F/A-18, F-22, Typhoon, Gripen, Tornado and Harrier. The AMRAAM has been used in several engagements and is credited with ten air-to-air kills.
AMRAAM has an all-weather, beyond-visual-range (BVR) capability. It improves the aerial combat capabilities of US and allied aircraft to meet the threat of enemy air-to-air weapons as they existed in 1991. It also incorporates a datalink to guide the missile to a point where its active radar turns on and makes terminal intercept of the target. Once the missile closes in on the target, its active radar guides it to intercept. This feature, known as “fire-and-forget”, frees the aircrew from the need to further provide guidance, enabling the aircrew to aim and fire several missiles simultaneously at multiple targets and perform evasive maneuvers while the missiles guide themselves to the targets. The missile also features the ability to “Home on Jamming,” giving it the ability to switch over from active radar homing to passive homing – homing on jamming signals from the target aircraft.
The missile uses this information to fly on an interception course to the target using its built-in inertial navigation system (INS). This information is generally obtained using the launching aircraft’s radar, although it could come from an infra-red search and track system, from a data link from another fighter aircraft, or from an AWACS aircraft. After launch, if the firing aircraft or surrogate continues to track the target, periodic updates—such as changes in the target’s direction and speed—are sent from the launch aircraft to the missile, allowing the missile to adjust its course, via actuation of the rear fins, so that it is able to close to a self-homing distance where it will be close enough to “catch” the target aircraft in the basket (the missile’s radar field of view in which it will be able to lock onto the target aircraft, unassisted by the launch aircraft).
The AMRAAM-Extended Range missile is a new, ground-launched solution that will intercept targets at longer distances and higher altitudes. The AMRAAM-ER missile gets its boost in range from a bigger rocket motor and smarter flight control algorithms. Designed specifically for ground-based air defense, the AMRAAM-ER missile will be integrated into the NASAMS launcher to provide increased air defense protection in the medium range air defense market. The Norwegian Advanced Surface-to-Air Missile System (NASAMS), developed by Kongsberg Defence & Aerospace, consists of a number of vehicle-pulled launch batteries (containing six AMRAAMs each) along with separate radar trucks and control station vehicles. A more recent version of the program is the High Mobility Launcher, made in cooperation with Raytheon (Kongsberg Defence & Aerospace was already a subcontractor on the SLAMRAAM system), where the launch-vehicle is a Humvee (M1152A1 HMMWV), containing four AMRAAMs each. NASAMS is deployed by seven countries, and is on contract for two more, and has been integrated into the U.S.’ National Capital Region’s air defense system since 2005.