Disciplining a Rubidium Atomic Clock Based on Adaptive Kalman Filter

Area of Science:

• Atomic Physics
• Control Systems Engineering
• Metrology

Background:

• Rubidium atomic clocks are crucial for Global Navigation Satellite Systems (GNSS) but suffer from poor long-term stability.
• Accurate timekeeping is essential for navigation, communication, and scientific research.

Purpose of the Study:

• To develop and evaluate a novel control system for enhancing the long-term stability of rubidium atomic clocks.
• To improve the accuracy and frequency stability of rubidium atomic clocks for demanding applications.

Main Methods:

• Development of an adaptive Kalman filtering algorithm for clock disciplining.
• Utilizing Autocovariance Least Squares (ALS) for accurate estimation of clock noise parameters.
• Experimental validation against Coordinated Universal Time (UTC) standards.

Main Results:

• The adaptive Kalman filtering algorithm demonstrated high estimation accuracy for clock noise parameters.
• Achieved a standard deviation of clock error better than 2.568 nanoseconds (ns) against UTC.
• Improved peak-to-peak clock error values to within 11.358 ns.
• Reduced frequency stability to 3.06 × 10^-13 @100,000 s.

Conclusions:

• The proposed adaptive Kalman filtering algorithm is an accurate and effective control strategy for rubidium atomic clock discipline.
• The developed system significantly enhances the performance of rubidium atomic clocks, making them more suitable for high-precision applications.