A communication unit and a method for calibrating the alignment of a communication unit in a mobile carrier platform are described. The method incudes the following steps: determining an initial alignment of the communication unit with the moon on the basis of a position and bearing of the mobile carrier platform; moving the communication unit so that it adopts the initial alignment; tracing a search pattern with the communication unit starting from the initial alignment until a detection unit detects the moon; determining a real alignment of the communication unit when the detection unit detects the moon; determining a difference between the initial alignment and the real alignment of the communication unit; using this difference when performing a target alignment with the communication unit.