An Autonomous Satellite Time Synchronization System Using Remotely Disciplined VC-OCXOs.

Area of Science:

• Space Technology
• Satellite Communication
• Metrology

Background:

• Accurate time synchronization is critical for satellite-to-satellite and ground-to-satellite communication.
• Existing systems require frequent manual intervention and lack robustness in diverse operational scenarios.

Purpose of the Study:

• To develop an autonomous remote clock control system for robust and precise time synchronization.
• To enable long-term, unattended operation in various satellite time transfer applications.

Main Methods:

• Utilized on-board voltage controlled oven controlled crystal oscillators (VC-OCXOs) disciplined by a remote master atomic clock.
• Employed a novel architecture integrating frequency division duplex (FDD), synchronous time division duplex (STDD), and code division multiple access (CDMA).
• Incorporated dual one-way ranging for clock error measurement, least square (LS) methods for prediction, and a third-order phase lock loop (PLL) for control.

Main Results:

• Proposed a general functional model for the autonomous clock control system.
• Discussed error sources and delays impacting time synchronization, with algorithms for estimation and correction.
• Simulated system performance, providing guidance for clock selection.

Conclusions:

• The proposed system offers a robust and autonomous solution for satellite time transfer.
• The novel architecture and error correction algorithms enhance synchronization accuracy and reliability.
• This system is widely applicable to various satellite communication scenarios.