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26 October 2004 MODIS on-orbit calibration: key issues and approaches
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MODIS, one of the key instruments for the NASA's Earth Observing System (EOS), is currently operating on both the Terra and Aqua spacecraft making continuous observations in 36 spectral bands from 0.4 to 14.5μm. A complete suite of on-board calibrators (OBC) have been designed for the instruments on-orbit calibration and characterization, including a solar diffuser (SD) and solar diffuser stability monitor (SDSM) system for the radiometric calibration of the 20 reflective solar bands (RSB), a blackbody (BB) for the radiometric calibration of the 16 thermal emissive bands (TEB), and a spectro-radiometric calibration assembly (SRCA) for the spatial (all bands) and spectral (RSB only) characterization. The task of continuously performing high quality on-orbit calibration and characterization of all 36 spectral bands with a total of 490 detectors located on four focal plane assemblies is extremely challenging. The use of a large two-sided paddle wheel scan mirror with a ±55° scan angle range and a retractable pinhole attenuation screen in front of the SD panel for calibrating the high gain bands have resulted in additional unanticipated complexity. In this paper, we describe some of the key issues in the Terra and Aqua MODIS on-orbit calibration and characterization, and discuss the methods developed to solve these problems or to reduce their impact on the Level 1B calibration algorithms. Instrument performance and current issues are also presented.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xiaoxiong Xiong, K. Chiang, Junqiang Sun, Nianzeng Che, and William L. Barnes "MODIS on-orbit calibration: key issues and approaches", Proc. SPIE 5542, Earth Observing Systems IX, (26 October 2004);


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