Quartz Oscillator Rotation Testing for Accurate G-Sensitivity
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Solution Overview
Problem
Existing methods for measuring the g-sensitivity of quartz oscillators incorporated in high-precision systems like navigation receivers are inadequate, particularly when subjected to vibrational effects and mechanical forces, as they fail to accurately account for temperature drift and require complex, expensive equipment.
Innovation Solution
A method and system for measuring g-sensitivity by rotating the quartz oscillator around multiple orthogonal axes at a constant angular velocity, using a data fitting model to estimate the integral g-sensitivity vector, which accounts for thermal frequency variations and does not require continuous axis position indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional static testing methods are used to measure g-sensitivity, then the testing procedure is simple, but temperature drift effects are not accounted for and measurement accuracy deteriorates
Solution Approach 1:
The patent transitions from static testing to dynamic rotation testing. The oscillator is rotated at a constant angular velocity around orthogonal axes, converting the static measurement problem into a dynamic one. This allows differentiation between temperature drift (slow varying) and g-sensitivity effects (periodic with rotation), resolving the contradiction by making the measurement process dynamic rather than static.
Solution Approach 2:
The patent employs periodic rotation of the oscillator around orthogonal axes at constant angular velocity. The frequency measurements are taken at a predetermined rate during this periodic motion. The periodic nature of the rotation creates periodic frequency variations that can be distinguished from aperiodic temperature drift through spectral analysis, thereby improving measurement accuracy while maintaining operational simplicity.
2Measurement precision
If dynamic testing with vibration benches is used, then temperature drift can be accounted for, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex vibration benches with a simple rotation mechanism. Instead of using sophisticated mechanical vibration systems to create controlled accelerations, the invention uses simple rotational motion around orthogonal axes. The g-sensitivity is derived from frequency measurements during rotation combined with mathematical modeling, substituting mechanical complexity with mathematical analysis.
Solution Approach 2:
The patent introduces mathematical modeling and data fitting as an intermediary between the physical rotation and the g-sensitivity measurement. Rather than directly measuring g-sensitivity through complex vibration analysis, the invention uses frequency measurements as an intermediary, then applies mathematical models to extract g-sensitivity parameters, reducing the need for complex test equipment.
3Productivity
If high rotation speed is used during testing, then measurement rate increases, but thermal effects and centrifugal forces increase
Solution Approach 1:
The patent carefully selects and controls the rotation speed parameter to optimize the measurement process. The rotation is performed at constant angular velocity at a rate that provides sufficient measurement data points while remaining low enough to minimize thermal and centrifugal effects. This parameter optimization resolves the contradiction by finding the optimal rotation speed that balances measurement rate with minimizing harmful effects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides a robust, accurate, and practical method for measuring g-sensitivity, overcoming the limitations of conventional tests by simplifying equipment requirements and improving accuracy in estimating frequency shifts under vibrational conditions.
Implementation Method 1
quartz oscillators are used in many different devices, systems and applications that require a stable frequency reference
Implementation Method 2
g-sensitivity, which is defined as the relative change in the output frequency of an oscillator at an acceleration of one g applied to an oscillator, where g is the acceleration of gravity on the surface of the earth
Data Source
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AI summary
A method and system are provided for estimating the g-sensitivity of a quartz oscillator, which includes rotating the quartz oscillator successively around each of a plurality of axes constituting a full-rank system, measuring a frequency of the quartz oscillator at a predetermined rate as a function of time during rotation, and estimating an integral g-sensitivity vector while the quartz oscillator is rotated. Estimation can be performed utilizing a data fitting and estimation model, e.g., a Least Square Method (LSM) in one example, using the frequency measurements obtained while the quartz oscillator is in rotation around the axes. The method and system are especially useful for measuring g-sensitivity of quartz oscillators that are incorporated in high-precision systems, such as navigation receivers, which operate in environments that are subjected to vibrational effects and other mechanical forces.