SACLOS (short for Semi-Automatic Command to Line-Of-Sight) is a second-generation method of missile guidance. In SACLOS, the operator has to continually point a sighting device at the target while the missile is in flight. Electronics in the sighting device and/or the missile then guide it to the target. A missile (British English: miss-isle; U.S. English: missl) is, in general, a projectile—that is, something thrown or otherwise propelled. ... Two digital voltmeters The field of electronics is the study and use of electronic devices that operate by controlling the flow of electrons or other electrically charged particles in devices such as thermionic valves and semiconductors. ...

There are two common ways SACLOS can work:

Wire and radio-guided SACLOS

The sighting device can calculate the angular difference in direction from the missile position to the target location. It can then give electronic instructions to the missile that correct its flight path so it is flying along a straight line from the sighting device to the target.

These instructions are delivered either by a radio link or a wire. Radio links have the disadvantage of being jammable, whereas wire links have the disadvantage of being limited to the length of the wire. The term Jamming can refer to several things: Jamming as an electronic warfare (EW) - a technique to limit the effectiveness of an opponents communications and/or detection equipment, like Radio Jamming and Radar Jamming E-Mail Jamming- used by electronic political activists or hackers to disable e-mail systems...

Beam-riding SACLOS

With beam-riding SACLOS, the sighting device emits a directional signal that "illuminates" the target. A detector in the missile looks for the signal, either in the nose of the missile looking for a signal reflected from the target, or in the tail of the missile looking for the beam from the emitter. Electronics in the missile then keep it centered in the beam.

Radar was the most common form of SACLOS signals in early systems, because, in the anti-aircraft role the target is typically being hit by a radar signal anyway. However, a beam-riding missile flies directly at the target, which is often inefficient for a high-speed target like an aircraft. For this reason, most anti-aircraft missiles follow their own route to the target, and do not "ride" the beam. This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ... American troops man an anti-aircraft gun near the Algerian coastline in 1943 Anti-aircraft, or air defense, is any method of combating military aircraft from the ground. ...

A more modern use of beam-riding uses a laser illuminator pointed by the operator. This illuminates the target, and the missile head has a detector for the frequency of light emitted by the laser and can therefore guide itself to the target. Laser (US Air Force) A LASER (Light Amplification by Stimulated Emission of Radiation) is an optical device which uses a quantum mechanical effect called stimulated emission (discovered by Einstein while researching the photoelectric effect) in order to generate a coherent beam of light from a lasing medium of controlled purity...

Examples of SACLOS-guided missiles

• Wire-guided SACLOS: MILAN, Swingfire
• Radio-guided SACLOS: ASM-N-2 Bat, 9K33 'Osa' (SA-8 'Gecko')
• laser beam riding SACLOS: Kornet, Starstreak, rocket launcher in Half-Life 2

Location within Italy Image:IMG 8480. ... Swingfire is a wire-guided anti-tank missile in service with the British Army. ... An SA-8 9K33M3 TELAR w/Land Roll radars. ... The Kornet is a Russian anti-tank guided missile (ATGM). ... Starstreak is a British short range surface-to-air missile, also known as Starstreak HVM where HVM stands for High Velocity Missile. ... Half-Life 2 is a first-person shooter computer game and the highly anticipated sequel to Half-Life, developed by Valve Software. ...

See also

command guided, MCLOS, Fire-and-forget Command guidance is a type of missile guidance where a ground station or aircraft relay signals to a guided missile via radio (or possibly through a wire connecting the missile to the launcher) and tell the missile where to steer in order to intercept its target. ... MCLOS (short for Manual Command to Line of Sight) is a first-generation method for guiding guided missiles. ... Fire and forget is the military term for a type of missile which does not require further guidance after launch such as illumination of the target, and can hit its target without the launcher being in line of sight of the target. ...