System for synchronizing a ground segment to a beam hopping satellite

A satellite communication system arranged for consecutively illuminating a plurality of contours on earth and comprising:

• a transmitter device arranged for generating a signal to be transmitted and comprising:
• one or more hopping framers each arranged for receiving a sequence of bits and for organizing said sequence of bits into a hopping frame according to a hopping plan indicating an order in which said plurality of contours is to be illuminated;
• an encoder per hopping framer for mapping said hopping frame to a sequence of digital symbols;
• a modulator per hopping framer arranged for receiving said sequence of digital symbols and for modulating said digital symbols on a waveform at a symbol rate, thereby obtaining a modulated signal to be transmitted, and for initiating transmission of said modulated signal at a time instant equal to a Start of Hopping Frame, SoHF, time instant, said modulator being arranged for indicating to said hopping framer when a next hopping frame is needed, whereby said hopping framer is arranged for inserting dummy data if not sufficient bits are available in said sequence of bits when said next hopping frame is needed;
• a satellite comprising a beam hopping transponder arranged for receiving said modulated signal and for outputting a version of said modulated signal to an illumination circuit arranged in said satellite for steering illumination from one contour to another particular contour of said plurality of contours according to said hopping plan, said illumination of said one contour starting at a switching time instant;
• one or more receiver devices in said particular contour of said plurality of contours to be illuminated and arranged for receiving said outputted version of said modulated signal;
• a central controller having an established communication link with at least one of said receiver devices and arranged for receiving via said established link information on observed illumination transitions, said central controller comprising computation means for computing updated timing information for aligning in time said transmitter device with said beam hopping transponder, based on said information on observed illumination transitions and being in connection with said transmitter device for passing said updated timing information to said transmitter device.