A method for focusing a beam of a high energy radiation source on a reference point on the surface of a flying object, comprising: recording a number of consecutive two-dimensional images of the flying object determining the trajectory of the flight path simultaneously determining the line of sight angle between the image acquisition device and the position of the flying object calculating a three-dimensional model of the flying object displaying the currently acquired two-dimensional image marking the reference point on the displayed two-dimensional image of the flying object; calculating the three-dimensional reference point on the surface of the flying object focusing the beam of the high energy radiation source on the three-dimensional reference point.