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A Common Calibration Source Framework for Fully-Polarimetric and Interferometric RadiometersTwo types of microwave radiometry--synthetic thinned array radiometry (STAR) and fully-polarimetric (FP) radiometry--have received increasing attention during the last several years. STAR radiometers offer a technological solution to achieving high spatial resolution imaging from orbit without requiring a filled aperture or a moving antenna, and FP radiometers measure extra polarization state information upon which entirely new or more robust geophysical retrieval algorithms can be based. Radiometer configurations used for both STAR and FP instruments share one fundamental feature that distinguishes them from more 'standard' radiometers, namely, they measure correlations between pairs of microwave signals. The calibration requirements for correlation radiometers are broader than those for standard radiometers. Quantities of interest include total powers, complex correlation coefficients, various offsets, and possible nonlinearities. A candidate for an ideal calibration source would be one that injects test signals with precisely controllable correlation coefficients and absolute powers simultaneously into a pair of receivers, permitting all of these calibration quantities to be measured. The complex nature of correlation radiometer calibration, coupled with certain inherent similarities between STAR and FP instruments, suggests significant leverage in addressing both problems together. Recognizing this, a project was recently begun at NASA Goddard Space Flight Center to develop a compact low-power subsystem for spaceflight STAR or FP receiver calibration. We present a common theoretical framework for the design of signals for a controlled correlation calibration source. A statistical model is described, along with temporal and spectral constraints on such signals. Finally, a method for realizing these signals is demonstrated using a Matlab-based implementation.
Document ID
20010016273
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Kim, Edward J.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Davis, Brynmor
(Arizona Univ. AZ United States)
Piepmeier, Jeff
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Zukor, Dorothy J.
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Subject Category
Instrumentation And Photography
Meeting Information
Meeting: Microwave Radiometer Calibration
Location: College Park, MD
Country: United States
Start Date: October 30, 2000
End Date: October 31, 2000
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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