A Method for Autonomous Generation of High-Precision Time Scales for Navigation Constellations

Area of Science:

• Satellite Navigation
• Timekeeping Systems
• Atomic Clocks

Background:

• Navigation constellation time accuracy is crucial for user positioning and autonomous operation.
• Atomic clock frequency stability onboard satellites is a key factor in maintaining time accuracy.
• Developing constellation-level synthetic atomic time is a trend in Global Navigation Satellite Systems (GNSS).

Purpose of the Study:

• To propose a framework for generating navigation constellation time scales.
• To improve the stability of navigation constellation time-frequency systems.
• To enhance autonomous navigation capabilities through precise timekeeping.

Main Methods:

• Developed a navigation constellation time scale generation framework.
• Designed an improved Kalman plus weights (KPW) time scale algorithm integrating genetic algorithms.
• Implemented a time-frequency steer algorithm.

Main Results:

• Simulated 30-day autonomous timekeeping using GPS precision clock data.
• Achieved Allan deviations of 5.73 × 10^-14 (300s interval, 71% improvement) and 8.87 × 10^-16 (1x10⁶s interval, 94% improvement).
• Demonstrated significant stability improvements compared to traditional KPW algorithms.

Conclusions:

• The proposed constellation-level time scale generation technology substantially enhances navigation constellation autonomous timekeeping stability.
• This advancement is vital for improving the performance and reliability of future autonomous navigation systems.
• The integrated genetic algorithm approach offers a more robust and stable timekeeping solution.