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Published on: March 6, 2017
Residual Asymmetry Modeling and Joint Time-Frequency Estimation for High-Dynamic Two-Way Microwave Links.
Zhijuan Hao1,2, Huabing Wu1,3
1National Time Service Center, Chinese Academy of Sciences, Xi'an 710600, China.
Sensors (Basel, Switzerland)
|June 12, 2026
Summary
This study introduces a new method to improve time synchronization for high-speed platforms. It accurately estimates errors in microwave links, achieving sub-nanosecond precision even under challenging conditions.
Area of Science:
- Engineering
- Signal Processing
- Navigation Systems
Background:
- High-precision time synchronization is critical for distributed systems involving high-dynamic platforms.
- Two-way microwave links face challenges like propagation asymmetry, Doppler shifts, and link degradation, impacting synchronization accuracy.
- Existing compensation methods may leave residual errors that degrade clock-offset estimation.
Purpose of the Study:
- To propose a novel method for modeling and jointly estimating residual asymmetric errors in high-dynamic two-way microwave links.
- To enhance the stability and accuracy of time synchronization in challenging operational environments.
- To address the limitations of current compensation techniques in high-dynamic scenarios.
Main Methods:
- Modeling residual asymmetric error as a recursively estimable dynamic state with its rate of change.
- Developing a four-timestamp and frequency-offset joint observation model.
- Employing a link-state-information-assisted IMM-IEKF (Interacting Multiple Model - an extended Kalman filter) for online joint estimation.
Main Results:
- The proposed method effectively models and estimates residual asymmetric errors.
- Sub-nanosecond synchronization accuracy was achieved under strong-dynamic and degraded-link conditions.
- The joint observation model enhances the separability of clock offset, frequency offset, and residual link state.
Conclusions:
- The developed method offers a robust solution for time synchronization in high-dynamic systems.
- Accurate estimation of residual errors is key to achieving high-precision synchronization.
- This approach improves the reliability of networked operations for high-speed mobile platforms.
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