Digital array gas radiometer (DAGR): a sensitive and reliable trace gas detection concept

Larry L. Gordley; Martin J. McHugh; B. T. Marshall; Earl Thompson

doi:10.1117/12.818538

30 April 2009 Digital array gas radiometer (DAGR): a sensitive and reliable trace gas detection concept

Larry L. Gordley, Martin J. McHugh, B. T. Marshall, Earl Thompson

Proceedings Volume 7312, Advanced Environmental, Chemical, and Biological Sensing Technologies VI; 73120F (2009) https://doi.org/10.1117/12.818538
Event: SPIE Defense, Security, and Sensing, 2009, Orlando, Florida, United States

Abstract

The Digital Array Gas Radiometer (DAGR) concept is based on traditional and reliable Gas Filter Correlation Radiometry (GFCR) for remote trace gas detection and monitoring. GFCR sensors have been successful in many infrared remote sensing applications. Historically however, solar backscatter measurements have not been as successful because instrument designs have been susceptible to natural variations in surface albedo, which induce clutter and degrade the sensitivity. DAGR overcomes this limitation with several key innovations. First, a pupil imaging system scrambles the received light, removing nearly all spatial clutter and permitting a small calibration source to be easily inserted. Then, by using focal plane arrays rather than single detectors to collect the light, dramatic advances in dynamic range can be achieved. Finally, when used with the calibration source, data processing approaches can further mitigate detector non-uniformity effects. DAGR sensors can be made as small as digital cameras and are well suited for downlooking detection of gases in the boundary layer, where solar backscatter measurements are needed to overcome the lack of thermal contrast in the IR. Easily integrated into a satellite platform, a space-based DAGR would provide near-global sensing of climatically important species such as such as CO, CH₄, and N₂O. Aircraft and UAV measurements with a DAGR could be used to monitor agricultural and industrial emissions. Ground-based or portable DAGRs could augment early warning systems for chemical weapons or toxic materials. Finally, planetary science applications include detection and mapping of biomarkers such as CH₄ in the Martian atmosphere.

Citation Download Citation

Larry L. Gordley, Martin J. McHugh, B. T. Marshall, and Earl Thompson "Digital array gas radiometer (DAGR): a sensitive and reliable trace gas detection concept", Proc. SPIE 7312, Advanced Environmental, Chemical, and Biological Sensing Technologies VI, 73120F (30 April 2009); https://doi.org/10.1117/12.818538

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