Interferometric Sensing Motion Compensation via Spectral Domain Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical Frequency Domain Reflectometry (OFDR) measurements are degraded by time-varying disturbances such as motion of the sensing fiber or its connections during the laser sweep, leading to inaccurate strain and alignment measurements.
Innovation Solution
An optical interrogation system that includes an optical interferometric interrogator, detection circuitry, and data processing circuitry to detect and compensate for time-varying disturbances by transforming interferometric measurement signals into the spectral domain, extracting phase signals, and applying compensating signals to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If OFDR measurements are performed over a wide frequency range during laser sweep, then spatial resolution is improved, but measurement accuracy deteriorates due to time-varying disturbances from fiber motion
Solution Approach 1:
The patent extracts and separates the motion-induced phase error from the total measured phase signal. By identifying and isolating the time-varying phase component caused by fiber motion, the system can remove this error term from the measurement, thereby maintaining high spatial resolution while improving measurement accuracy in dynamic environments.
Solution Approach 2:
The system implements a feedback mechanism where the measured phase signal is analyzed to detect motion-induced errors, and correction algorithms are applied to compensate for these errors. This closed-loop approach continuously refines the measurement by comparing expected phase values with actual measurements and applying appropriate corrections.
2Manufacturing precision
If the laser sweep time is extended to cover a wide frequency range, then spatial resolution is improved, but the system becomes more sensitive to fiber motion during measurement
Solution Approach 1:
The patent converts the harmful effect of fiber motion during the extended laser sweep into a useful measurement signal. By detecting the phase changes induced by motion and analyzing their temporal characteristics, the system can identify and correct for these disturbances, transforming what was previously a source of error into information that enables compensation.
Solution Approach 2:
The system performs preliminary analysis of the phase signal to predict and prepare for motion-induced errors before they significantly degrade the measurement. By monitoring phase variations in real-time during the laser sweep, the system can anticipate motion effects and apply appropriate corrections to maintain measurement integrity throughout the extended sweep duration.
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
The system effectively compensates for motion and strain along the sensing fiber, improving the accuracy of OFDR measurements by correcting for distortions caused by time-varying changes, thereby maintaining high-resolution strain sensing capabilities even in dynamic environments.
Implementation Method 1
an optical interferometric interrogator and optical detection circuitry, coupled to the optical interferometric interrogator, for detecting optical interferometric measurement signals
Data Source
AI summary
Interferometric measurement signals are detected by a single optical interferometric interrogator for a length of a sensing light guide and an interferometric measurement data set corresponding to the interferometric measurement signals is generated. The interferometric measurement data set is transformed into a spectral domain to produce a transformed interferometric measurement data set. The transformed interferometric measurement data set is compared to a baseline interferometric data set to identify a time-varying signal corresponding to a time-varying disturbance. The baseline interferometric data set is representative of the sensing light guide not being subjected to the time-varying disturbance. A compensating signal is determined from the time-varying signal and used to compensate at least a portion of the interferometric measurement data set for the time-varying disturbance as part of producing a measurement of the parameter.