Pseudorandom noise code-based technique for thin-cloud discrimination with CO

• Published in: Optical Engineering 2011-12, Vol.50 (12), p.126002-126002
• Main Authors: Campbell, Joel F, Prasad, Narasimha S, Flood, Michael A
• Format: Article
• Language: English
• ISSN: 0091-3286; 1560-2303
• DOI: 10.1117/1.3658758

NASA Langley Research Center is working on a continuous wave (cw) laser-based remote sensing scheme for the detection of CO and O from space-based platforms suitable for an active sensing of CO2 emissions over nights, days, and seasons (ASCENDS) mission. ASCENDS is a future space-based mission to determine the global distribution of sources and sinks of atmospheric carbon dioxide (CO ). A unique, multifrequency, intensity modulated cw laser absorption spectrometer operating at 1.57 m for CO sensing has been developed. Effective aerosol and cloud discrimination techniques are being investigated in order to determine concentration values with accuracies less than 0.3%. In this paper, we discuss the demonstration of a pseudonoise code-based technique for cloud and aerosol discrimination applications. The possibility of using maximum length sequences for range and absorption measurements is investigated. A simple model for accomplishing this objective is formulated. Proof-of-concept experiments carried out using a sonar-based LIDAR simulator that was built using simple audio hardware provided promising results for extension into optical wavelengths.