Mid-course update

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 possibly through a wire connecting the missile to the launcher: Wire-guided missile) 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.

The CLOS system uses only the angular coordinates between the missile and the target to ensure the collision. The missile is made to be in the line of sight between the launcher and the target (LOS), and any deviation of the missile from this line is corrected. Since so many types of missile use this guidance system, they are usually subdivided into four groups:A particular type of command guidance and navigation where the missile is always to commanded lie on the line of sight (LOS) between the tracking unit and the aircraft is known as command to line of sight (CLOS) or three-point guidance. That is, the missile is controlled to stay as close as possible on the LOS to the target after missile capture.is used to transmit guidance signals from a ground controller to the missile. More specifically, if the beam acceleration is taken into account and added to the nominal acceleration generated by the beam-rider equations, then CLOS guidance results. Thus, the beam rider acceleration command is modified to include an extra term. The beam-riding performance described above can thus be significantly improved by taking the beam motion into account. CLOS guidance is used mostly in shortrange air defense and antitank systems.

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Wikipedia