Guidance Control system

• The control aspect of the guidance system is intended to stabilise the behaviour of the airframe. 
• The fact that the guidance system will always have some finite bandwidth, and therefore will not be able to respond instantaneously to the commends generated by the guidance law, means that the dynamical model will never be perfect and there will be differences (errors) between the required acceleration in the actual acceleration achieved.

          - A typical example would be where the airframe was not at trim, and the angular velocities generated by the control surfaces were sufficiently large to cause the airframe to oscillate wildly.

• A control system is used to drive these errors to zero, rather than letting them dominate the behaviour of the system. Generally, this involves some form of closed-loop feedback and, possibly, angle rate and acceleration measurements from inertial sensors.