In this paper, a reflective methane (CH₄) gas telemetry system has been developed based on the direct optical absorption spectroscopy technique for an open light path. It can realize the real-time in-situ monitoring of CH₄ gas within a range of 150 m. Considering the potential cross-interference effects of hydrocarbon gases in ambient air, a diode laser operating at a specific wavelength of 1653.7 nm is employed to target the strong CH₄ absorption line in near-infrared region and therefore avoid the interference of water vapor absorption simultaneously. A measurement precision of 0.02 ppm within 40 m open optical path has been achieved over 30 h of continuous monitoring, indicating the excellent measuring sensitivity and stability of our telemetry system. Through the field test of leaked CH₄ gas with a 150 m one-way open optical path, the developed CH₄ telemetry system has proved to have great potential and reliability for environmental monitoring and remote gas detection in various industries.

在本文中，基于直接光吸收光谱技术的开放光路，开发了一种反射式甲烷（CH ₄）气体遥测系统。它可以实现150 m范围内CH ₄气体的实时原位监测。考虑到环境气体中碳氢化合物气体的潜在交叉干扰效应，使用在1653.7 nm特定波长下工作的二极管激光器瞄准强CH ₄吸收线位于近红外区域，因此可以同时避免水蒸气吸收的干扰。在连续监测30小时的过程中，在40 m的开放光路内达到0.02 ppm的测量精度，表明我们的遥测系统具有出色的测量灵敏度和稳定性。通过使用150 m单向开放光路对泄漏的CH ₄气体进行现场测试，事实证明，开发的CH ₄遥测系统在各种行业的环境监测和远程气体检测中具有巨大的潜力和可靠性。