Satellite-Referenced Oscillator Aging Estimation Under Poor Signal Quality
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Solution Overview
Problem
Existing oscillators, such as TCXO and OCXO, face challenges in maintaining high frequency stability over time due to aging effects, which can lead to variations in oscillation frequency, especially when the precision of the reference signal from GPS satellites decreases, affecting aging estimation precision.
Innovation Solution
A circuit device that includes an oscillation signal generation circuit and a processing circuit, which estimates the aging characteristic of the oscillation frequency by comparing the phase of a satellite signal with a clock signal and uses an index value representing the reliability of the satellite signal state to improve aging estimation precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If aging correction is performed using phase comparison between reference signal and clock signal, then oscillation frequency stability is improved, but measurement precision deteriorates when satellite signal quality is poor
Solution Approach 1:
The patent introduces a reliability evaluation mechanism that acts as an intermediary between the phase comparison result and the aging estimation process. When satellite signal reliability is low, the system selectively weights or discards phase comparison data, preventing poor-quality measurements from degrading the aging estimation accuracy while still allowing good-quality data to improve frequency stability.
Solution Approach 2:
The system dynamically adjusts the aging estimation process based on the reliability of satellite signals. The estimation algorithm transitions between different operational modes: using phase comparison data when reliability is high, and relying on historical aging characteristics when reliability is low. This dynamic adaptation resolves the contradiction by optimizing measurement usage in real-time according to signal conditions.
2Stability of the object's composition
If phase comparison is continuously performed for aging estimation, then frequency stability is maintained, but reliability of estimation deteriorates under poor satellite signal conditions
Solution Approach 1:
The system performs preliminary evaluation of satellite signal reliability before using phase comparison results for aging estimation. This preliminary action filters out unreliable measurements in advance, ensuring that only high-quality phase comparison data contributes to the aging estimation, thereby maintaining estimation reliability while still providing continuous frequency stability through selective data usage.
3Stability of the object's composition
If reference signal from GPS satellite is used for phase comparison, then oscillation frequency can be stabilized, but precision of reference signal varies with satellite signal state
Solution Approach 1:
The patent changes the parameter of reference signal usage based on satellite signal quality. When satellite signal precision is high, the system actively uses the reference signal for phase comparison and aging estimation. When precision degrades, the system reduces or suspends reference signal usage, switching to alternative methods such as historical aging data or internal oscillation characteristics, thereby maintaining frequency stability without being adversely affected by poor reference signal quality.
Data Source
AI summary
A circuit device includes an oscillation signal generation circuit that generates an oscillation signal by using a resonator and a processing circuit that estimates an aging characteristic of the oscillation frequency of the resonator based on the result of comparison between the phase of a reference signal based on a satellite signal transmitted from a navigation satellite and the phase of a clock signal based on the oscillation signal. The processing circuit estimates the aging characteristic based on an index value representing the reliability of the state of the received satellite signal and the result of the phase comparison.