Satellite Clock Ensemble Synchronization via Dynamic Master Switching
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Solution Overview
Problem
Current satellite systems face challenges in maintaining precise timekeeping, particularly in space environments where frequent updates are necessary to maintain positioning accuracy, and existing methods either focus on improving individual clock hardware or averaging time readings, but lack robustness against diverse system-threatening scenarios.
Innovation Solution
A master/slave ensembling algorithm is implemented where satellites are designated as either master or slave, with clocks cross-linked for time and frequency synchronization, and the master designation changes based on performance indicators, allowing for robust timekeeping and error minimization across the constellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual clock hardware is improved to maintain precise timekeeping, then timekeeping accuracy is improved, but system complexity and cost increase
Solution Approach 1:
Multiple satellite clocks are merged into a single ensemble timescale, where individual clock readings are averaged to create a more accurate reference time. This combines the functionality of multiple clocks to achieve higher precision without requiring each individual clock to be highly complex or expensive.
Solution Approach 2:
The ensemble timescale serves as a universal reference for all satellites in the constellation, allowing each satellite to use the same averaged time reference rather than requiring individual high-precision clocks. This multi-functional approach benefits the entire system through a shared solution.
2Measurement precision
If ground-station updates are performed frequently to maintain nanosecond-level timekeeping, then positioning accuracy is improved, but loss of time increases
Solution Approach 1:
The ensemble timescale is pre-computed by averaging individual clock readings over time, creating a stable reference that can be used between ground-station updates. This preliminary averaging action allows the system to maintain accuracy without requiring frequent ground contact.
Solution Approach 2:
The ensemble timescale provides continuous time reference functionality between discrete ground-station updates, allowing satellites to maintain accurate timing autonomously. The useful action of timekeeping continues uninterrupted even when ground contact is lost.
3Device complexity
If a single master satellite is used for time synchronization, then system complexity is reduced, but reliability decreases due to single point of failure
Solution Approach 1:
The master satellite designation is dynamic rather than static, allowing the system to switch between different satellites based on performance indicators. This dynamic reconfiguration maintains system robustness while preserving the simplicity of a single-master architecture during normal operation.
Solution Approach 2:
The system monitors performance indicators of individual satellites and uses this feedback to determine when to switch master satellites. This feedback mechanism ensures the system automatically adapts to changing conditions, maintaining reliability without requiring complex manual intervention.
4Measurement precision
If individual clocks are made more accurate, then timekeeping precision is improved, but weight and power consumption increase
Solution Approach 1:
Instead of requiring each satellite to carry heavy, high-precision individual clocks, the system merges the functionality of multiple clocks into a shared ensemble timescale. This allows satellites to use lighter, less precise individual clocks while achieving high precision through the ensemble averaging process.
Data Source
AI summary
Time-synchronization of a space-system having a plurality of satellites. During a first period, a first satellite of the plurality of satellites is designated as a master satellite. A clock of the master satellite is configured to provide time and frequency to remaining satellites of the plurality of satellites and the remaining satellites are designated as slave satellites. During a second period, a second satellite of the slave satellites is designated as the master satellite based on a performance indicator and the first satellite is designated as a slave satellite. During the first period and the second period, clocks of the slave satellites are crosslinked with a clock of the master satellite using time transfer. At least one satellite during the first period and the second period, delivers time data having the time and the frequency generated by a clock of the at least one satellite.