Mesh Satellite Terminal Synchronization Using Ephemeris Data
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Solution Overview
Problem
Traditional gateway-based synchronization methods in mesh satellite communications are inadequate for establishing timing between user terminals, as they do not provide sufficient timing information for the link between each user terminal and the satellite, leading to synchronization challenges in mesh communication systems.
Innovation Solution
The use of ephemeris data and terminal measurements to modify the start of transmit and receive frame settings for terminals or gateways, allowing for synchronization in mesh satellite communications by adjusting frame timing based on changing distances between satellites and terminals, and employing self-synchronization techniques using terminal-to-terminal bursts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gateway-based synchronization methods are used, then timing for gateway-to-terminal links can be established, but timing information for terminal-to-terminal mesh communication links is insufficient
Solution Approach 1:
The patent segments the synchronization problem into two distinct parts: gateway-to-terminal synchronization (handled by traditional methods) and terminal-to-terminal mesh link synchronization (handled by new terminal-based methods). Each segment uses appropriate synchronization techniques tailored to its specific requirements, allowing precise timing for both gateway communications and direct terminal mesh communications independently
Solution Approach 2:
The patent introduces terminal measurements and ephemeris data as intermediary elements that bridge the gap between gateway-based synchronization and mesh link requirements. These intermediaries provide the additional timing information needed for terminal-to-terminal communications without replacing the existing gateway synchronization infrastructure
2Ease of operation
If gateway-based synchronization is used, then terminal timing can be set based on gateway signals, but changes in satellite-to-gateway distance are not adequately compensated
Solution Approach 1:
The patent implements feedback mechanisms where terminals continuously measure their own receive timings and compare them against expected timings derived from ephemeris data. The differences (errors) are fed back to adjust terminal transmit timings, creating a closed-loop system that automatically compensates for distance variations between satellite and gateway, maintaining synchronization accuracy despite orbital movements
Solution Approach 2:
The patent changes the parameter basis for synchronization from purely gateway-referenced timing to a hybrid approach incorporating terminal-measured timing and ephemeris-derived distance corrections. This parameter change allows the system to adapt to varying satellite-gateway distances by adjusting timing parameters based on actual measured conditions rather than fixed gateway references
3Measurement precision
If terminal measurements and ephemeris data are used to adjust frame timing, then synchronization accuracy improves, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating expected receive timings using ephemeris data before actual communications occur. Terminals use this pre-computed timing information as a reference framework, reducing the real-time computational burden and complexity during actual synchronization operations, while still achieving high precision through the combination of pre-calculated and measured data
Data Source
AI summary
Methods, systems, and devices are described for synchronization in mesh satellite communications. The arrival time of the gateway signal may be used to set a start of receive frame time for a terminal. A received control signal from the gateway may then be used to set a start of transmit frame time for the user terminal. The distance between the satellite and the gateway may change. Ephemeris data, various collections of terminal measurements, or terminal sync bursts may be used to modify start of transmit frame or start of receive frame settings for the terminal or gateway.