Lidar-based gas analyzer for remote sensing of atmospheric methane

Enhancement of methane emission measurement techniques is necessary to address the need for greenhouse gas emissions monitoring. Here we introduce a gas analyzer designed for remote sensing of atmospheric methane aboard unmanned aerial vehicles. This device employs the wavelength modulation laser spectroscopy approach and quadrature detection of laser radiation scattered from the underlying surface. This method is conceptually similar to the operating principle of lidar-based rangefinders, and the device also provides distance measurement capabilities. Our results demonstrate that the observed correlation between various signal attributes and the distance to the surface, where laser radiation scatters, aligns with analytical expectations. Calibrations proved that the instrument provides reliable methane measurements up to 120 m while being lightweight and power efficient. The presented device operates at a sampling rate of 19 Hz and achieves a measurement resolution of 15 ppm & sdot;m at an altitude of 50 m. Notably, this device surpasses its competitors in performance at higher altitudes, which offer greater safety for piloting.