DIAL Fluid Detection with Reflectivity Correction
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Solution Overview
Problem
Differential absorption LIDAR systems face challenges in accurately detecting fluid leaks due to low signal-to-noise ratios and variations in surface reflectivity, leading to false alarms and errors in concentration path length estimates.
Innovation Solution
A method and system that transmit multiple pulse bursts with both on-line and off-line pulses, using a CPL estimator to determine concentration path lengths and correct for reflectivity variations, forming a target fluid map with error estimation and spatial location association.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DIAL systems use on-line and off-line lasers for trace fluid detection, then the ability to detect target fluid concentration is improved, but the signal-to-noise ratio deteriorates because on-line returns are typically not much higher in energy than background noise
Solution Approach 1:
The patent segments the detection process by separating on-line and off-line laser transmissions and processing their returns independently through different signal processing paths. This allows targeted optimization of each wavelength's signal characteristics while maintaining the differential absorption measurement capability.
Solution Approach 2:
The patent implements feedback mechanisms where the detected on-line and off-line returns are continuously compared and processed to adjust signal processing parameters. This feedback loop enables dynamic optimization of the measurement signal while compensating for background noise variations.
2Measurement precision
If DIAL systems transmit laser beams for remote fluid detection, then the detection capability is improved, but surface reflectivity variations cause corresponding variations in on-line and off-line returns leading to detection errors
Solution Approach 1:
The patent extracts the surface reflectivity component from the total signal by using the off-line laser returns as a reference. By separating and analyzing the reflectivity variation independently, the system can remove this harmful factor from the final concentration calculation.
Solution Approach 2:
Instead of trying to directly measure and correct surface reflectivity variations in the traditional way, the patent inverts the approach by using the off-line returns (which are not absorbed by target fluid) as the reference for what the surface reflectivity should be, then comparing on-line returns against this inverted reference to eliminate reflectivity effects.
3Measurement precision
If multiple lasers with different wavelengths are used for trace fluid detection, then the ability to distinguish target fluid from swamp gas is improved, but the system complexity increases
Solution Approach 1:
The patent makes the laser system multi-functional by configuring it to operate at multiple wavelengths using either multiple lasers or a single tunable laser. This universal design allows the same hardware platform to detect different target fluids and distinguish them from swamp gas by analyzing spectral characteristics at various wavelengths.
Solution Approach 2:
The patent changes the operational parameters of the laser system by tuning the wavelength to match different target fluid absorption features. This parameter adjustment allows flexible adaptation to detect various fluids without requiring completely different hardware configurations for each detection scenario.
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
Enhances the accuracy of fluid leak detection by improving signal processing and noise reduction, reducing false alarms and errors in concentration path length estimates, and providing a precise target fluid map.
Implementation Method 1
Differential absorption LIDAR (DIAL) systems may be used to remotely measure the chemical composition of fluids in the atmosphere. The wavelength of one of the lasers, referred to as the on-line laser, is typically selected to coincide with a strong absorption feature of the fluid to be detected. The wavelength of another of the lasers, referred to as the off-line laser, is typically selected such that it is not absorbed by the target fluid.
Implementation Method 2
Differential absorption LIDAR (DIAL) systems may be used to remotely measure the chemical composition of fluids in the atmosphere.
Data Source
AI summary
Methods and systems for obtaining a target fluid map of a survey area using a differential absorption LIDAR (DIAL) system are provided. Pulse bursts are transmitted toward the survey area, where each pulse burst includes an off-line pulse and at least one on-line pulse. Pulse bursts, each being associated with a measurement point, are received from the survey area. A concentration path length (CPL) corresponding to a respective on-line pulse, a spatial location associated with the CPL, and an error associated with the CPL are determined for each measurement point. The CPL for each measurement point is arranged within the survey area to form the target fluid map.