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Design, fabrication, and testing of a data acquisition and control system for an internally-calibrated wide-band microwave airborne radiometer

Date

2014

Authors

Nelson, Scott P., author
Reising, Steven C., advisor
Notaros, Branislav, committee member
Kummerow, Christian, committee member

Journal Title

Journal ISSN

Volume Title

Abstract

The National Aeronautics and Space Administration (NASA)'s Earth Science Technology Office (ESTO) administers the Instrument Incubator Program (IIP), providing periodic opportunities to develop laboratory, ground-based and airborne instruments to reduce the risk, cost and schedule of future Earth Science missions. The IIP-10 project proposed in 2010 and led by PI S. Reising at Colorado State University focuses on the development of an internally-calibrated, wide-band airborne radiometer to reduce risks associated with wet-path delay correction for the Surface Water and Ocean Topography (SWOT) mission. This airborne radiometer includes microwave channels at 18.7, 23.8, and 34.0 GHz at both H and V polarizations; millimeter-wave window channels at 90.0, 130.0, 168.0 GHz; and temperature and water vapor sounding channels near 118 and 183 GHz, respectively. These microwave, millimeter-wave window and millimeter-wave sounding channels consist of 6, 3 and 16 channels, respectively, for a total of 25 channels in this airborne instrument. Since the instrument is a prototype for space flight, a great deal of effort has been devoted to minimizing the mass, size and power consumption of the radiometer's front-end. Similar goals of minimizing the mass, size and power consumption have driven the design of the radiometer back-end, which performs the data acquisition and control functions for the entire instrument. The signals output from all 25 radiometer channels are conditioned, integrated and digitized on the analog back-end boards. The radiometer system is controlled by a Field Programmable Gate Array (FPGA) and a buffer board. Each analog back-end board conditions and simultaneously samples four signals, performing analog-to-digital conversion. The digital back-end consists of the buffer board and FPGA, which control and accept data from all seven analog back-end boards required to sample all 25 radiometer channels. The digital back-end also controls the radiometer front-end calibration (also called "Dicke") switching and the motor used to perform cross-track scanning and black body target calibration of the airborne radiometer instrument. The design, fabrication, and test results of the data acquisition and control system are discussed in depth. First, a system analysis determines general requirements for the airborne radiometer back-end. In the context of these requirements, the design and function of each component are described, as well as its relationship to the other components in the radiometer back-end. The hardware and software developed as part of this radiometer back-end are described. Finally, the back-end testing and results of these tests are discussed.

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Subject

ESTO
JPL
MMIC
MSL
NASA
radiometer

Citation

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