Remote Gas Sensing With Generalized PoD for Emission Rate Accuracy
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Solution Overview
Problem
Existing methods for determining gas emission rate detection sensitivity face challenges due to a multi-dimensional and statistical parameter space that is complex, intractable, and often inaccurate, making it difficult to reliably and accurately estimate emission rates, especially in large geographic areas.
Innovation Solution
A method and system using remote gas sensors to collect gas concentration measurements, determine true positive detections, and generate a generalized probability of detection (PoD) function based on gas flow speed and concentration noise, allowing for the characterization of emission rate detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional point sensor methods or closed-path trajectories are used for emission rate measurement, then measurement reliability may be maintained, but device complexity and measurement time increase significantly
Solution Approach 1:
The patent replaces complex mechanical measurement systems (closed-path trajectories requiring multiple passes and stable platform operations) with an optical remote sensing system using lidars and spectroscopy. This substitution maintains measurement reliability while dramatically reducing operational complexity and measurement time by enabling open-path measurements without physical constraints
Solution Approach 2:
The patent employs a multi-functional sensor platform that integrates multiple lidars (CO2, H2O, and generic gas lidars) and spectroscopy systems into a single measurement apparatus. This universal system can simultaneously measure multiple gas species, wind speed, and temperature, eliminating the need for separate measurement systems and reducing overall device complexity
2Measurement precision
If closed-path trajectory methods are used for mass balance measurements, then emission rate accuracy may be achieved, but measurement time and operational complexity increase
Solution Approach 1:
The patent performs preliminary characterization of the measurement environment by measuring wind speed and temperature profiles before conducting emission rate measurements. This preliminary action enables the system to plan and execute more efficient measurement trajectories, reducing the number of passes required and thereby decreasing measurement time while maintaining accuracy
Solution Approach 2:
The patent transitions from static closed-path trajectories to dynamic open-path measurement approaches where the sensor platform can adapt its measurement path based on real-time wind conditions and plume location. This dynamic approach allows for more efficient data collection, reducing measurement time while maintaining the precision needed for accurate emission rate calculation
3Speed
If remote gas sensing techniques are used for plume visualization, then localization speed improves, but measurement precision for emission rate quantification decreases
Solution Approach 1:
The patent merges multiple remote sensing techniques (lidar-based plume visualization and spectroscopy-based concentration measurement) into a unified measurement system. By combining these methods, the system achieves both rapid plume localization through lidar imaging and precise emission rate quantification through spectroscopic concentration measurements, eliminating the trade-off between speed and precision
Solution Approach 2:
The patent uses wind speed and temperature measurements as intermediary parameters that link the remote plume visualization data with emission rate quantification. These intermediary measurements enable the system to translate visual plume location and shape information into accurate emission rate calculations, maintaining both localization speed and quantification precision
4Measurement precision
If tracer correlation method is used for emission rate measurement, then measurement accuracy improves, but device complexity and operational difficulty increase
Solution Approach 1:
The patent extracts and eliminates the need for tracer gas releases by using natural plume emissions combined with remote sensing measurements. This extraction of the tracer requirement simplifies implementation significantly, as it removes the need for tracer gas storage, release mechanisms, and controlled injection systems, while still achieving accurate emission rate measurements through direct observation of natural plumes
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
Enables accurate estimation of emission rates by accounting for environmental and operational parameters, improving the confidence in detection sensitivity and reducing false negatives, especially in complex environments.
Implementation Method 1
active remote gas sensing techniques, such as light detection and ranging (lidar) and open path spectroscopy systems
Data Source
AI summary
Apparatuses systems and methods for gas emission rate detection sensitivity and probability of detection (PoD) based on emission rate. A measurement system may be characterized by its ability to detect gas plumes as a function of the emission rate of those plumes. The measurement system may be characterized based on a generalized PoD function which expresses PoD relative to emission rate as a function of gas concentration noise and gas flow speed. In an example application, the PoD may be used to estimate a cumulative distribution of gas plumes which were not detected based on a cumulative distribution of measured gas plumes. In another example application, the PoD may be used to refine an estimate for a measured emission rate.