Ground Segment Synchronization for Beam Hopping Satellites
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Solution Overview
Problem
Current satellite communication systems face challenges in aligning transmitter signals with beam hopping satellites, leading to inefficiencies and potential misalignment issues, particularly in beam hopping systems where the satellite switches between multiple contours, requiring precise timing synchronization to maximize throughput.
Innovation Solution
The implementation of a satellite communication system that includes a hopping framer and a central controller to synchronize the transmitter with the beam hopping satellite, using a distributed time correction loop and symbol rate adjustments to ensure accurate alignment with the satellite's beam switching times, allowing seamless switching between contours and maintaining synchronization even with redundant transmitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the satellite switches beams between multiple contours dynamically, then the flexibility to direct communication traffic to receivers is improved, but the time alignment between transmitter signals and satellite illumination is worsened
Solution Approach 1:
The system performs preliminary actions by pre-calculating and distributing timing information to ground transmitters before the actual beam switching occurs. The satellite broadcasts timing advance information in advance, allowing ground stations to prepare their transmission schedules beforehand, ensuring precise synchronization when the beam switches to their contour.
Solution Approach 2:
The system implements feedback mechanisms where the satellite continuously provides timing information about its beam switching schedule to ground transmitters. This feedback loop allows real-time adjustment and correction of transmission timing, ensuring that signals are sent at the correct moments even as the satellite dynamically reconfigures its beam pattern.
2Reliability
If the transmitter continuously transmits to ensure uninterrupted service, then the service continuity is improved, but the risk of buffer overflow and timing misalignment is worsened
Solution Approach 1:
The system applies dynamics by making the transmission schedule adaptive rather than fixed. The ground transmitters dynamically adjust their transmission timing based on real-time satellite beam switching information. This dynamic scheduling allows continuous service while preventing buffer overflow by aligning transmission bursts with actual satellite illumination periods.
Solution Approach 2:
The system maintains continuity of useful action by ensuring that transmission resources are continuously allocated and utilized efficiently. The hopping framer continuously manages the transmission schedule, and the satellite continuously provides timing information, creating an uninterrupted flow of synchronized communication without gaps or overlaps.
3Reliability
If multiple transmitters are used for redundancy, then the system reliability is improved, but the synchronization difficulty is worsened
Solution Approach 1:
The system applies universality by creating a common synchronization framework that all transmitters must adhere to. The satellite's beam switching schedule serves as a universal timing reference that all ground transmitters use for coordination. This universal timing protocol enables multiple transmitters to operate independently yet synchronously, facilitating redundancy without increasing overall complexity.
Data Source
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AI summary
The present invention relates to a satellite communication system arranged for consecutively illuminating a plurality of contours on earth and comprising : - a transmitter to generate a signal to be transmitted and comprising * encoding means for mapping a sequence of bits, organized into a hopping frame according to a hopping plan, to a sequence of digital symbols, * modulation means 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 transmission of the modulated signal, said modulation means being arranged for indicating when a next hopping frame is needed, - a satellite comprising a beam hopping transponder arranged for receiving the modulated signal and for outputting a version of the modulated signal to an illumination circuit arranged in the satellite for steering illumination from one contour to another particular contour according to the hopping plan, said illumination of that one contour starting at a switching time instant, - one or more receivers in said particular contour of the contours to be illuminated and arranged for receiving the outputted signal, - a central controller having an established communication link with at least one of the receivers and arranged for receiving via an established link information on observed illumination transitions, said central controller comprising computation means for computing an adjusted symbol rate for the transmitter based on a comparison of the observed illumination transitions with a target switching time instant.