brings it into an angle of attack. This is dealt with in the 'Axis Control' chapter. The drift itself is then either controlled visually by the quadcopter pilot himself or with a superimposed controller that uses GPS as a sensor. This regulation is dealt with in the chapter 'GPS Control'. There are many controller structures for quadcopters in the literature. The one discussed here was deliberately chosen so that it can be implemented with as many flight controllers as possible. In particular, the separation into a subordinate axis control and a superimposed GPS control corresponds to the state of the art in quadcopter controls.