Semi-automatic command to line of sight (SACLOS) is a method of missile
command guidance
Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept its ...
. In SACLOS, the operator has to continually point a sighting device at the target while the missile is in flight.
Electronics
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
in the sighting device and/or the missile then guide it to the target.
Many SACLOS weapons are based on an
infrared seeker
Infrared homing is a passive weapon guidance system which uses the infrared (IR) light emission from a target to track and follow it seamlessly. Missiles which use infrared seeking are often referred to as "heat-seekers" since infrared is radi ...
aligned with the operator's
gunsight
A sight is an aiming device used to assist in visually aligning ranged weapons, surveying instruments or optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligne ...
or sighting
telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
. The seeker tracks the missile, either the hot exhaust from its
rocket
A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...
motor or
flare
A flare, also sometimes called a fusée, fusee, or bengala in some Latin-speaking countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, ...
s attached to the missile airframe, and measures the angle between the missile and the centerline of the operator's sights. This signal is sent to the missile, often using
thin metal wires or a
radio link
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...
, which causes it to steer back toward the center of the line-of-sight. Common examples of these weapons include the
BGM-71 TOW
The BGM-71 TOW ("Tube-launched, Optically tracked, Wire-guided") is an American anti-tank missile. TOW replaced much smaller missiles like the SS.10 and ENTAC, offering roughly twice the effective range, a more powerful warhead, and a greatly ...
wire-guided
anti-tank guided missile
An anti-tank guided missile (ATGM), anti-tank missile, anti-tank guided weapon (ATGW) or anti-armor guided weapon is a guided missile primarily designed to hit and destroy heavily armored military vehicles. ATGMs range in size from shoulder ...
(ATGM) and the
Rapier
A rapier () or is a type of sword with a slender and sharply-pointed two-edged blade that was popular in Western Europe, both for civilian use (dueling and self-defense) and as a military side arm, throughout the 16th and 17th centuries.
Impor ...
radio-command
surface-to-air missile
A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...
(SAM).
Another class of SACLOS weapons is based on the
beam riding
Beam-riding, also known as Line-Of-Sight Beam Riding (LOSBR) or beam guidance, is a technique of directing a missile to its target by means of radar or a laser beam. The name refers to the way the missile flies down the guidance beam, which is ai ...
principle. In this case, a signal is sent from the operator's sights toward the target. The signal is generally radio or a
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
. The missile has receivers for the signal on the rear of the fuselage. Some form of encoding is used in the signal so that the missile can steer itself into the center of the beam. Changing frequencies or dot patterns are also commonly used. These systems have the advantage that the link between the launcher and missile cannot easily be broken or jammed. But, they have a disadvantage because the guidance signal may be detected by the target. Examples include the laser-guided
RBS 70
RBS 70 (Robotsystem 70) is a man-portable air-defense system (MANPADS) designed for anti-aircraft warfare in all climate zones and with little to no support from other forces. Originally designed and manufactured by the Swedish defence firm of ...
SAM and
9M119 Svir ATGM.
Wire and radio-guided SACLOS
With
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. Most antitank SACLOS systems such as Milan and TOW use a strobe or flare (
visible
Visibility, in meteorology, is a measure of the distance at which an object or light can be seen.
Visibility may also refer to:
* A measure of turbidity in water quality control
* Interferometric visibility, which quantifies interference contrast ...
,
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
(IR) or
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
(UV) light) in the tail of the missile with an appropriate sensor on the firing post, to track the missile's flight path. The launching station incorporates a tracking camera with two lenses. A wide field of view lens that locates and "gathers" the missile near the center of the gunners line of sight immediately after launch, and a narrow view lens with automatic zoom that accomplishes the fine tracking adjustments. In most configurations, the narrow field camera utilizes electronics that translate the brightest spot in the view – the flare or strobe of the missile – into an electrical impulse. This impulse changes as the missile leaves the center of the field of view, and the electronics automatically apply a correction instruction in the opposite direction of the change to re-center the missile.
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 disadvantages of being limited to the length of the wire and fragile (i.e. not very good for penetrating/attacking targets in vegetated areas such as forests) and can not be fired over bodies of water due to potential shorting of the wires. Also, wires leave a trace all the way to the target, which could help find the source of the fire.
;Examples:
* Wire-guided:
HOT
Hot or the acronym HOT may refer to:
Food and drink
*Pungency, in food, a spicy or hot quality
*Hot, a wine tasting descriptor
Places
* Hot district, a district of Chiang Mai province, Thailand
**Hot subdistrict, a sub-district of Hot Distric ...
,
MILAN
Milan ( , , Lombard: ; it, Milano ) is a city in northern Italy, capital of Lombardy, and the second-most populous city proper in Italy after Rome. The city proper has a population of about 1.4 million, while its metropolitan city h ...
,
Swingfire
Swingfire was a British wire-guided anti-tank missile developed in the 1960s and produced from 1966 until 1993. The name refers to its ability to make a rapid turn of up to ninety degrees after firing to bring it onto the line of the sighting ...
,
AT-4 Spigot
The 9K111 ''Fagot'' (russian: Фагот; "bassoon") is a second-generation tube-launched semi-automatic command to line of sight (SACLOS) wire-guided anti-tank missile system of the Soviet Union for use from ground or vehicle mounts. The 9K111 F ...
,
AT-5 Spandrel
The 9M113 ''Konkurs'' (russian: 9М113 «Конкурс»; en, "Contest"; NATO reporting name AT-5 ''Spandrel'') is a Soviet SACLOS wire-guided anti-tank missile.
A development of the 9K111 Fagot with greater firepower, the 9M113 Konkurs ca ...
,
M47 Dragon
The M47 Dragon, known as the FGM-77 during development, is an American shoulder-fired, man-portable anti-tank guided missile system. It was phased out of U.S. military service in 2001, in favor of the newer FGM-148 Javelin system.
The M47 Drago ...
,
AT-7 Saxhorn
The 9K115 Metis (; NATO reporting name AT-7 Saxhorn) is a man-portable, tube launched, SACLOS wire-guided anti-tank guided missile of the Soviet Union. It is considered the Soviet counterpart to the American M47 Dragon ATGM.
The relatively small ...
,
BGM-71 TOW
The BGM-71 TOW ("Tube-launched, Optically tracked, Wire-guided") is an American anti-tank missile. TOW replaced much smaller missiles like the SS.10 and ENTAC, offering roughly twice the effective range, a more powerful warhead, and a greatly ...
,
Bumbar
The Bumbar ( sr-cyr, Бумбар, Bumbar, lit=Bumblebee) is a Serbian short-range portable anti-tank missile system.
Description
The Bumbar is a wire-guided, man-portable, short-ranged missile system for use against ground targets. The missile h ...
,
Baktar-Shikan
The HJ-8 or Hongjian-8 and Baktar Shikan (Pakistani version) () is a second generation tube-launched, optically tracked, wire-guided anti-tank missile system which was originally deployed by China's People's Liberation Army since the late 1980s. ...
* Radio-guided:
ASM-N-2 Bat
The ASM-N-2 Bat was a United States Navy World War II radar-guided glide bomb which was used in combat beginning in April 1944. It was developed and overseen by a unit within the National Bureau of Standards (which unit later became a part of ...
,
9K33 'Osa' (SA-8 'Gecko'),
Javelin surface to air missile
Beam-riding SACLOS
With
beam-riding
Beam-riding, also known as Line-Of-Sight Beam Riding (LOSBR) or beam guidance, is a technique of directing a missile to its target by means of radar or a laser beam. The name refers to the way the missile flies down the guidance beam, which is ai ...
SACLOS, the sighting device emits a directional signal directed toward the target. A detector in the tail of the missile looks for the signal. Electronics in the missile then keep it centered in the beam.
It differs from
semi-active radar homing
Semi-active radar homing (SARH) is a common type of missile guidance system, perhaps the most common type for longer-range Air-to-air missile, air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is ...
(SARH) and
semi-active laser homing
Laser guidance directs a robotics system to a target position by means of a laser beam. The laser guidance of a robot is accomplished by projecting a laser light, image processing and communication to improve the accuracy of guidance. The key ide ...
(SALH) in which the target is illuminated by a powerful emitter, and a sensor in the head of missile detects the reflected emissions and directs it to the target.
Radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
was the most common form of SACLOS signals in early systems, because, in the
anti-aircraft
Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based, ...
role the target is typically already being ''illuminated'' by a radar signal. 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 intercept the target, and do not ''ride'' the beam. A more modern use of beam-riding uses
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
signals because they are compact, less sensitive to distance, and are difficult to detect and jam.
This was also one of the main advantages over concurrent SALH systems: regarding detection laser riding beam emitter is typically a low powered device and does not need to be pointed immediately to the target, and because the missile sensor ''looks'' backward to it, the whole system is impervious to most
jamming devices. Another advantage in antitank applications is that the backward-looking guidance system does not interfere with the process of jet formation of
high-explosive anti-tank
High-explosive anti-tank (HEAT) is the effect of a shaped charge explosive that uses the Munroe effect to penetrate heavy armor. The warhead functions by having an explosive charge collapse a metal liner inside the warhead into a high-velocity ...
(HEAT) charges, thus maximizing weapon's effectiveness.
However, such systems don't allow for a
top-attack mode, or target illumination from a different source than the launcher itself, so choice between the two operating modes may vary between operators.
The main disadvantage of both SACLOS guidance systems in an anti-tank role is that working on angular differences evaluation, it does not allow any notable separation between guidance system and missile launch post the opposite of
manual command to line of sight
Manual command to line of sight (MCLOS) is a method for guiding guided missiles.
With an MCLOS missile, the operator must track the missile and the target simultaneously and guide the missile to the target. Typically the missile is steered with a ...
(MCLOS) ones, thus allowing updated version of such anti-tank weapons (notably AT-3
Malyutka) to still remain in service in some countries.
;Examples:
*
9M133 Kornet
The 9M133 Kornet (russian: Корнет; "Cornet", NATO reporting name AT-14 Spriggan, export designation Kornet-E) is a Military of Russia, Russian man-portable anti-tank missile, anti-tank guided missile (ATGM) intended for use against main ...
*
9M119 Svir
*
HJ-9
The HJ-9, HongJian-9 (), military designation AFT-9, is an advanced, third-generation, man-portable or vehicle-mounted anti-tank missile system deployed by the People's Liberation Army Ground Force.
History and development
The development of HJ-9 ...
*
MSS-1.2
The MSS-1.2 is Brazilian Anti-tank guided missile with laser guidance used for close-range fighting. It is the standard personal missile launch system of the Brazilian army and marine corps. The MSS 1.2 has a range of 500 to 3,000 m and can be ...
*
RBS-70
RBS 70 (Robotsystem 70) is a man-portable air-defense system (MANPADS) designed for anti-aircraft warfare in all climate zones and with little to no support from other forces. Originally designed and manufactured by the Swedish defence firm of ...
*
Shershen
*
Starstreak
Starstreak is a British short-range surface to air missile that can be used as a man-portable air-defence system (MANPADS) or in heavier systems, manufactured by Thales Air Defence (formerly Shorts Missile Systems), in Belfast, Northern Ireland. ...
*
ZT3 Ingwe
The ZT3 Ingwe (Leopard) is a modern South African multi-role laser beam riding anti-tank guided missile (ATGM) manufactured by Denel Dynamics (formerly Kentron).
Design and development
The ZT3 and its launch system were developed under the co ...
See also
*
Command guidance
Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept its ...
*
Manual command to line of sight
Manual command to line of sight (MCLOS) is a method for guiding guided missiles.
With an MCLOS missile, the operator must track the missile and the target simultaneously and guide the missile to the target. Typically the missile is steered with a ...
(MCLOS)
*
Fire-and-forget
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 targe ...
{{Missile types
Missile guidance