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On measurement noise in the European TWSTFT network
Dirk Piester1, Andreas Bauch, Jürgen Becker
1Physikalisch-Technische Bundesanstalt Braunschweig, Germany.
Summary
Optimizing satellite time transfer (TWSTFT) for Galileo involves managing network traffic. A less congested transponder significantly reduces timing jitter and improves frequency transfer accuracy, ensuring reliable synchronization for critical systems.
Area of Science:
- Satellite communication
- Metrology
- Navigation systems
Background:
- Two-way satellite time and frequency transfer (TWSTFT) is crucial for modern timing applications, including the Galileo satellite navigation system.
- Understanding link performance under various operational parameters is essential for network optimization.
Purpose of the Study:
- To investigate the impact of operational parameters on TWSTFT link performance in a multistation network.
- To determine optimal configurations for TWSTFT, particularly for integrating Galileo's precise timing facilities (PTFs).
Main Methods:
- Analysis of TWSTFT performance with varying numbers of transmitting stations, transmit/receive power, and chip rates.
- Measurement of 1 pps jitter and Allan deviation to quantify timing noise and frequency transfer stability.
Main Results:
- A "quiet" transponder (2 stations) reduced measurement noise (1 pps jitter) by 1.4x compared to a busy one (12 stations).
- Frequency transfer capability (Allan deviation) improved at short averaging times in less congested networks.
- Higher transmit power improved signal quality but caused interference; lower chip rates increased jitter significantly.
Conclusions:
- Network congestion is a primary factor affecting TWSTFT performance, with quieter channels yielding better results.
- Galileo PTFs can be integrated into existing networks if suitable ground equipment is implemented.
- Careful consideration of transmit power and chip rates is necessary to balance performance and interference.
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