Enhanced-range remote-sensing of fugitive Methane using retroreflector-based DLAS System with RTK Integration for improved location accuracy on a UAV Pair

Methane is one of the most potent greenhouse gases in our atmosphere, with various anthropogenic factors increasing its prevalence. Methane has 28 times greater heating capacity than carbon dioxide and its atmospheric concentration has increased roughly from 800 parts-per-billion (ppb) in the early 1900s to an alarming 1800 ppb in 2016. With approximately 3.2 million abandoned wells in the US, mitigating fugitive emissions was designated a high priority by the Biden administration. While we have ample satellite or tower data that provide global or point concentrations/flux of greenhouse gas emissions, we have little understanding of localized “topology” of emission and transport. Without that knowledge we do not know where our hidden carbon offenders lie and thus cannot mitigate leaks. Several COTS methane sensors in use can provide some information at scale on methane presence or information on concentration but they are fixed systems. They are not able to scale or be adaptive to varied terrain and operations, or to 3D mapping of intricate and complex topographies, with high resolution both of spatial characteristics as well as low methane concentrations. To address the issues mentioned above and building on our Phase I effort, we offer the solution of remote sensing of fugitive methane using Retroreflector-Based Differential Laser Absorption Spectroscopy (DLAS) system on a UAV pair—termed our RetraSpectra™ system. Standalone DLAS systems based have demonstrated to be a reliable and accurate method of detecting low-concentration levels of fugitive gases. However, measurements without the use of a dedicated retroreflector are often noisy (function of the environment) and thus, cannot be scaled to measure larger columns of interest. Utilizing a retroreflector on one UAV and a ground-based DLAS, detection range of fugitive leaks can be measured in significantly less time as compared to currently used manual methods, coupled with an RTK system, cm-level location accuracy can be obtained. In Phase II, Censys Technologies Corporation looks to commercialize its RetraSpectra system whilst proving out sensor metrics such as accuracy, resolution, response time to be comparable or better than existing COTS sensors.