Stationary and drone-assisted methane plume localization with dispersion spectroscopy

• Published in: Remote sensing of environment 2023-05, Vol.289 (C), p.113513, Article 113513
• Main Authors: Soskind, Michael G., Li, Nathan P., Moore, Daniel P., Chen, Yifeng, Wendt, Lars P., McSpiritt, James, Zondlo, Mark A., Wysocki, Gerard
• Format: Article
• Language: English
• Subjects: class; environment; Environmental Sciences & Ecology; GEOSCIENCES; Imaging Science & Photographic Technology; Laser spectroscopy; methane; natural gas; OTHER INSTRUMENTATION; Remote Sensing; Source attribution; spectroscopy; Standoff sensing; Target tracking
• ISSN: 0034-4257; 1879-0704
• DOI: 10.1016/j.rse.2023.113513

This work presents stationary and mobile retroreflector-based remote sensing techniques for methane leak localization and quantification using chirped laser dispersion spectroscopy equipped with a custom laser transceiver capable of continuous tracking of a flying drone and coupled with inverse atmospheric gas dispersion modeling. The techniques demonstrate the ability to localize leaks as low as 0.13 g CH4·s−1, which are up to 25 times smaller than those typically observed at natural gas facilities, as well as actively track a moving retroreflector mounted on a lightweight (∼250 g) drone to enable spatial plume reconstruction. This system exhibited a 2.3 ppm-m sensitivity over pathlengths of 40–150 m. Source localization to within ±7 m is demonstrated using a modified horizontal radial plume mapping technique with a stationary retroreflector grid. Meanwhile, the mobile system utilizing a drone-mounted retroreflector is able to localize a controlled release within ±1 m of its source location and estimate leak rates using inversion techniques assuming type B Gaussian plume stability class within ±30% error with respect to the actual low flow rate releases. •A remote spectroscopic sensing system developed to quantify and localize emissions.•An advanced optical transceiver for active-tracking of a flying UAV-retroreflector.•Field demonstration of remote UAV-based location of emission sources to within ∼1 m.•Two different configurations tested using stationary and UAV-based retroreflectors.•Two inversion methods for tomographic plume mapping and emissions quantification.