Command guided
Encyclopedia
Command guidance is a type of missile guidance
in which 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. Additionally, it is possible to send a command to the missile to detonate, even if the missile itself has a fuze
or fuzes. (It may be possible to detonate the missile and destroy or damage the target, even though the missile was not actually going to strike the target, due to the blast radius
of the warhead
).
Typically, the system giving the guidance commands is tracking both the target and the missile or missiles via radar
. It determines the position and velocity of the target and the position and velocity of the missile and calculates whether their paths will intersect. If not, the guidance system will relay commands to the missile(s), telling them to move their fins in such a way to steer themselves in the direction necessary for them to end up on an interception course with the target. If the target maneuvers, the guidance system can notice this and update the missiles' course continuously to counteract the maneuvering. If the missile passes close to the target, either its own proximity
or contact fuze
will detonate the warhead, or the guidance system can estimate when the missile will pass near the target and send a detonation signal.
On some systems there is a dedicated radio antenna or antennas for communicating with the missile(s). On others, the radar itself is actually able to send coded pulses which the missile can pick up and interpret as guidance commands. Sometimes to aid the tracking station, the missile will contain a radio transmitter, making it easier to track. Also, sometimes there is a dedicated radar antenna on the tracking station for tracking the missile as well as one or more for tracking targets. It is especially these types of systems which may be able to communicate with the missile via the same radar energy it uses for tracking it.
Examples of missiles which use command guidance include:
Note that older western missiles tended to prefer using pure semi-active radar homing
.
Pure command guidance is not normally used in modern SAM
systems since it is too inaccurate during the terminal phase (when the missile is about to intercept the target). This is because the ground-based radars are distant from the target and the returned signal lacks resolution. However, it is still quite practical to use it to guide the missile to a location near the target, and then use another more accurate guidance method to actually intercept the target. Almost any type of terminal guidance can be used, but the most common are semi-active radar homing
(SARH) or active radar homing
.
Examples of missiles which use command guidance with terminal SARH
include:
Examples of missiles which use command guidance with terminal active radar homing
include:
Track-via-missile
is a variation of command guidance, the main difference being that the missile itself sends target tracking information back to the guidance system to aid it in calculating the intercept. This negates much of the accuracy disadvantage of pure command guidance.
MCLOS
and SACLOS
are variations of command guidance.
Missile guidance
Missile guidance refers to a variety of methods of guiding a missile or a guided bomb to its intended target. The missile's target accuracy is a critical factor for its effectiveness...
in which a ground station or aircraft relay signals to a guided missile
Guided Missile
Guided Missile is a London based independent record label set up by Paul Kearney in 1994.Guided Missile has always focused on 'the underground', preferring to put out a steady flow of releases and developing the numerous GM events around London and beyond....
via radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
(or possibly through a wire connecting the missile to the launcher) and tell the missile where to steer in order to intercept its target. Additionally, it is possible to send a command to the missile to detonate, even if the missile itself has a fuze
Fuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
or fuzes. (It may be possible to detonate the missile and destroy or damage the target, even though the missile was not actually going to strike the target, due to the blast radius
Blast radius
A blast radius is the distance from the source that will be affected when an explosion occurs. A blast radius is often associated with, but not limited to, bombs, mines, explosive projectiles , and other weapons with an explosive charge....
of the warhead
Warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...
).
Typically, the system giving the guidance commands is tracking both the target and the missile or missiles via radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
. It determines the position and velocity of the target and the position and velocity of the missile and calculates whether their paths will intersect. If not, the guidance system will relay commands to the missile(s), telling them to move their fins in such a way to steer themselves in the direction necessary for them to end up on an interception course with the target. If the target maneuvers, the guidance system can notice this and update the missiles' course continuously to counteract the maneuvering. If the missile passes close to the target, either its own proximity
Proximity fuze
A proximity fuze is a fuze that is designed to detonate an explosive device automatically when the distance to target becomes smaller than a predetermined value or when the target passes through a given plane...
or contact fuze
Contact fuse
A contact fuze, percussion fuze or direct-action fuze is the fuze that is placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface....
will detonate the warhead, or the guidance system can estimate when the missile will pass near the target and send a detonation signal.
On some systems there is a dedicated radio antenna or antennas for communicating with the missile(s). On others, the radar itself is actually able to send coded pulses which the missile can pick up and interpret as guidance commands. Sometimes to aid the tracking station, the missile will contain a radio transmitter, making it easier to track. Also, sometimes there is a dedicated radar antenna on the tracking station for tracking the missile as well as one or more for tracking targets. It is especially these types of systems which may be able to communicate with the missile via the same radar energy it uses for tracking it.
Examples of missiles which use command guidance include:
- Russian: SA-1 'Guild'SA-1 GuildThe S-25 Berkut is a surface-to-air guided missile, the first operational SAM system in the world. Its NATO reporting name is SA-1 Guild. It was used only to defend Moscow, while the more mobile S-75 would be used in almost all other roles...
, SA-2 'Guideline', SA-3 'Goa', SA-15 'Gauntlet' - American: Nike AjaxProject NikeProject Nike was a U.S. Army project, proposed in May 1945 by Bell Laboratories, to develop a line-of-sight anti-aircraft missile system. The project delivered the United States' first operational anti-aircraft missile system, the Nike Ajax, in 1953...
, Nike HerculesProject NikeProject Nike was a U.S. Army project, proposed in May 1945 by Bell Laboratories, to develop a line-of-sight anti-aircraft missile system. The project delivered the United States' first operational anti-aircraft missile system, the Nike Ajax, in 1953...
, Nike ZeusProject NikeProject Nike was a U.S. Army project, proposed in May 1945 by Bell Laboratories, to develop a line-of-sight anti-aircraft missile system. The project delivered the United States' first operational anti-aircraft missile system, the Nike Ajax, in 1953...
Note that older western missiles tended to prefer using pure semi-active radar homing
Semi-active radar homing
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external ...
.
Pure command guidance is not normally used in modern SAM
Surface-to-air missile
A surface-to-air missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft or other missiles...
systems since it is too inaccurate during the terminal phase (when the missile is about to intercept the target). This is because the ground-based radars are distant from the target and the returned signal lacks resolution. However, it is still quite practical to use it to guide the missile to a location near the target, and then use another more accurate guidance method to actually intercept the target. Almost any type of terminal guidance can be used, but the most common are semi-active radar homing
Semi-active radar homing
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external ...
(SARH) or active radar homing
Active radar homing
Active radar homing is a missile guidance method in which a guided missile contains a radar transceiver and the electronics necessary for it to find and track its target autonomously...
.
Examples of missiles which use command guidance with terminal SARH
Sarh
Sarh is the third largest city in Chad, after N'Djamena and Moundou. It is the capital of Moyen-Chari region and the department of Barh Köh. It lies 350 miles south-east of the capital Ndjamena on the Chari River...
include:
- Russian: SA-4 'Ganef', SA-6 'Gainful'SA-6 GainfulThe 2K12 "Kub" mobile surface-to-air missile system is a Soviet low to medium-level air defence system designed to protect ground forces from air attack. "2К12" is the GRAU designation of the system...
, SA-11 'Gadfly', SA-17 'Grizzly'
Examples of missiles which use command guidance with terminal active radar homing
Active radar homing
Active radar homing is a missile guidance method in which a guided missile contains a radar transceiver and the electronics necessary for it to find and track its target autonomously...
include:
- Russian: SA-5 'Gammon'
Track-via-missile
Track-via-missile
“Track-via-missile” refers to a missile guidance technique which combines features of semi-active radar homing and radio command guidance.-Explanation:TVM guidance requires a radar ground station and a missile with a radar receiver...
is a variation of command guidance, the main difference being that the missile itself sends target tracking information back to the guidance system to aid it in calculating the intercept. This negates much of the accuracy disadvantage of pure command guidance.
MCLOS
MCLOS
MCLOS is a first-generation 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 joystick, and its path is observed through a periscope-type...
and SACLOS
SACLOS
SACLOS is an acronym for Semi-Automatic Command to Line of Sight, 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...
are variations of command guidance.