Remote Digital Beam Forming for Satellite Broadcasting
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Solution Overview
Problem
Existing satellite-based broadcasting systems lack flexibility and configurability, as they are typically fixed at launch and cannot be upgraded to match advanced ground systems, with onboard satellite control systems being complex and limited in flexibility.
Innovation Solution
A satellite broadcasting system using remote digital beam forming (DBF) processors at ground-based uplink stations to create configurable downlink radiation patterns, allowing multiple simultaneous beams with different content to be directed to various geographic regions, and minimizing the impact of differential phase and amplitude drift through wavefront multiplexing and null channel calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed satellite systems are used at launch, then system stability is maintained, but adaptability and configurability deteriorate
Solution Approach 1:
The patent extracts the beam-forming control functionality from the satellite and relocates it to ground-based uplink stations. The satellite retains only simple signal reception and transmission functions, while the complex digital beam-forming processing is performed remotely on the ground, resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
Instead of controlling beam patterns from space (satellite to ground), the patent inverts the control direction by having ground stations control the satellite's downlink beams remotely. This inversion allows flexible reconfiguration without modifying the satellite's onboard systems.
2Productivity
If multiple simultaneous downlinks are implemented, then productivity increases, but loss of information from differential phase and amplitude drift worsens
Solution Approach 1:
The patent implements feedback mechanisms where ground-based uplink stations continuously monitor and measure the phase and amplitude characteristics of the uplink signals. This feedback information is used to dynamically adjust and equalize the beam-forming weights, compensating for differential drift effects and maintaining signal integrity across multiple simultaneous downlinks.
Solution Approach 2:
The system performs preliminary equalization and calibration of uplink channels before establishing multiple simultaneous downlinks. By pre-characterizing the channel conditions and pre-computing appropriate beam-forming weights, the system minimizes the impact of phase and amplitude drift before it affects the actual broadcast content.
Data Source
AI summary
A satellite broadcasting system is achieved where remote beam forming processors combined with wavefront multiplexers located among distributed ground stations are used to control downlink beam footprints and pointing directions. Digital beam forming (DBF) techniques allow a single satellite download broadcast antenna array to generate multiple independently pointed simultaneous downlinks, which may contain distinct information content. Allocation of some uplink back-channel elements as diagnostic signals allows for continuous calibration of uplink channels, improving downlink broadcast array and user broadcast performance. Wavefront multiplexing/demultiplexing allows all array element signals to be radiated by the broadcasting antenna array, with simultaneous propagation from ground stations to the broadcasting satellites through available parallel propagation channels in the uplinks of feeder links, with equalized amplitude and phase differentials. Further, additional wavefront multiplexing/demultiplexing pairs are further used to coherently broadcast signals from a remote beam forming facility on ground to cover areas through multiple broadcasting satellites.