Radiometer Calibration Using Colocated GPS Radio Occultation Measurements
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06740017.pdf
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Checksum (MD5)
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Author(s)
Cahoy, K. L.
Blackwell, W. J.
Bishop, R.
Cohen, B.
Crail, C.
Cucurull, L.
Dave, P.
DiLiberto, M.
Erickson, N.
Fish, C.
Date Issued
October 2014
Publisher
Institute of Electrical and Electronics Engineers
Citation
Blackwell, WJ, et al. "Radiometer Calibration Using Colocated GPS Radio Occultation Measurements." Ieee Transactions on Geoscience and Remote Sensing, vol. 52, no. 10, n.d., pp. 6423-6433. EBSCOhost, search.ebscohost.com/login.aspx?direct=true&db=edswsc&AN=000337173200035&site=eds-live&scope=site.
Abstract
We present a new high-fidelity method of calibrating a cross-track scanning microwave radiometer using Global Positioning System (GPS) radio occultation (GPSRO) measurements. The radiometer and GPSRO receiver periodically observe the same volume of atmosphere near the Earth's limb, and these overlapping measurements are used to calibrate the radiometer. Performance analyses show that absolute calibration accuracy better than 0.25 K is achievable for temperature sounding channels in the 50-60-GHz band for a total-power radiometer using a weakly coupled noise diode for frequent calibration and proximal GPSRO measurements for infrequent (approximately daily) calibration. The method requires GPSRO penetration depth only down to the stratosphere, thus permitting the use of a relatively small GPS antenna. Furthermore, only coarse spacecraft angular knowledge (approximately one degree rms) is required for the technique, as more precise angular knowledge can be retrieved directly from the combined radiometer and GPSRO data, assuming that the radiometer angular sampling is uniform. These features make the technique particularly well suited for implementation on a low-cost CubeSat hosting both radiometer and GPSRO receiver systems on the same spacecraft. We describe a validation platform for this calibration method, the Microwave Radiometer Technology Acceleration (MiRaTA) CubeSat, currently in development for the National Aeronautics and Space Administration (NASA) Earth Science Technology Office. MiRaTA will fly a multiband radiometer and the Compact TEC/Atmosphere GPS Sensor in 2015.
Subjects
Advanced Microwave Sounding Unit (AMSU)
calibration
Compact Total Electron Count (TEC)/Atmosphere Global Positioning System (GPS) Sensor (CTAGS)
CubeSat
Global Navigation Satellite System (GNSS)
GPS
GPS radio occultation (RO) (GPSRO)
humidity
Micro-sized Microwave Atmospheric Satellite (MicroMAS)
microwave
Microwave Radiometer Technology Acceleration (MiRaTA)
nanosatellite
precipitation
radiometer
remote sensing
RO
RO-Cal
temperature
MIT Department
Space Telecommunications Astronomy and Radiation (STAR) Lab
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Persistent DSpace Link
