Trajectory generation methods for radio and optical telescopes

The axes servo control of optical telescopes and antennas acts in two typical phases: the slew to a new target and the subsequent accurate tracking of the source. Although the tracking error minimization is paramount, a good design of the slewing phase is needed as well. In fact, saturations of velocity and acceleration can easily occur during telescope slew, introducing non-linearities in the control system which may lead to undesired behaviors. Also, sudden accelerations may trigger vibrations of the telescope structure, which may increase the slew time or even prevent a stable target acquisition. In this paper, a command pre-processor is adopted to provide recursively a valid path to reach the assigned target, never exceeding the specified rate and acceleration limits. Different generation methods are considered, with different degrees of smoothness and slewing time. Numerical simulations show their main features in different test cases, for both radio and optical telescopes.