2023-04-14 プリンストン大学
The retroflector mounted onto the drone. Photo by Bumper DeJesus
この技術は、他の手法では通常検出されない25倍小さいリークを正確に検出し、その源をメートル単位で特定できる。また、難易度の高い場所での見逃されがちなリークを素早く発見することもできるため、大気感知のための革新的な可能性を開くと研究者たちは語っている。
プリンストンの手法は、小さなドローンに小型の鏡を取り付けることで、センサーをドローンに取り付けることなく、基地局に分散分光法を用いた大型ガスセンサーを設置することで、センサーを基地局に移動させることができ、他のドローンでは困難な同時測定も可能になるという。
＜関連情報＞
- https://engineering.princeton.edu/news/2023/04/14/using-drones-and-lasers-researchers-pinpoint-greenhouse-gas-leaks
- https://www.sciencedirect.com/science/article/abs/pii/S0034425723000640
分散分光法を用いた定点観測とドローンによるメタンガスプルーム位置の特定 Stationary and drone-assisted methane plume localization with dispersion spectroscopy
Michael G. Soskind, Nathan P. Li, Daniel P. Moore, Yifeng Chen, Lars P. Wendt, James McSpiritt, Mark A. Zondlo, Gerard Wysocki
Remote Sensing of Environment Available online :1 March 2023
DOI:https://doi.org/10.1016/j.rse.2023.113513
Highlights
•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.
Abstract
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.
