Apparatus and method of remote gas trace detection
US6664533B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 20, 2000 |
| Grant date | Dec 16, 2003 |
| Priority date | — |
| Expiry date | Jan 20, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/1793
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This specification discloses a method and apparatus for the mobile and remote detection of a gas, such as methane, in the atmosphere. The apparatus includes a TDL based Light Detection and Ranging (LIDAR) driven at carrier frequency lying within the absorption line of the gas. The apparatus also drives the TDL with a modulation frequency to generate upper and lower sidebands in the output of the TDL and with a low ramp frequency to sweep the output of the TDL across twice the width of the pressure-broadened absorption line of the gas, preferably the first overtone absorption line in the case of methane detection. The apparatus include reference and calibration cells or chambers, and includes a light collector and detectors to detect the quantity and modulation of the light that passes the reference or calibration cells and that is received by the apparatus after reflection back toward the apparatus from an uncooperative target. The apparatus further includes a signal processor that applies a derivative spectroscopy technique, such as frequency modulation spectroscopy or wavelength modulation spectroscopy, to determine the presence of the gas in the atmosphere.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.