• The guidance law is used to generate a requirement (usually an required acceleration) that will achieve the guidance objective.
• In this course, we will look at three main types of guidance law.

- The simplest guidance law is ‘line of sight guidance', which aims to keep the velocity vector of the vehicle directed toward the objective, thereby ensuring that the vehicle reaches the objective.

- The most common guidance algorithm is ‘proportional navigation' (used in practically all guided weapons and aircraft autopilots). This  method aims to reduce the rate of change of the line of sight to zero and generates an acceleration control that is proportional to the  rate of change of the line of sight.
- More advanced algorithms use techniques taken from the theory of optimal control to improve system performance and robustness.