It determines the positions and velocities of a target and a missile, and calculates whether their paths will intersect.
If not, the guidance system will relay commands to a missile, telling it to move the fins in a way that steers in the direction needed to maneuver to an intercept course with the target.
On others, the radar can send coded pulses which a missile can sense and interpret as guidance commands.
The CLOS system uses only the angular coordinates between the missile and the target to ensure the collision.
In the case of glide bombs or missiles against ships or the supersonic Wasserfall against slow-moving B-17 Flying Fortress bombers this system worked, but as speeds increased MCLOS was quickly rendered useless for most roles.
Is similar to MCLOS but some automatic system positions the missile in the line of sight while the operator simply tracks the target.
SACLOS has the advantage of allowing the missile to start in a position invisible to the user, and is generally far easier to operate.
The guidance system ensures the interception of the target by the missile by locating both in space.
An example is later versions of the RIM-8 Talos missile as used in Vietnam: the radar beam was used to take the missile on a high arcing flight and then gradually brought down in the vertical plane of the target aircraft, the more accurate semi-active radar homing (SARH) being used at the last moment for the terminal homing and strike.
LOSBR suffers from the inherent weakness of inaccuracy with increasing range as the beam spreads out.
The main difference is that the missile sends target tracking information back to the guidance system to aid it to calculate an intercept.