Radiometer calibration using colocated GPS radio occultation measurements

AMS Citation:
Blackwell, W. J., and Coauthors, 2014: Radiometer calibration using colocated GPS radio occultation measurements. IEEE Transactions on Geoscience and Remote Sensing, 52, 6423-6433, doi:10.1109/TGRS.2013.2296558.
Date:2014-10-01
Resource Type:article
Title:Radiometer calibration using colocated GPS radio occultation measurements
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.
Peer Review:Refereed
Copyright Information:Copyright 2014 IEEE.
OpenSky citable URL: ark:/85065/d7p55pgh
Publisher's Version: 10.1109/TGRS.2013.2296558
Author(s):
  • William Blackwell
  • Rebecca Bishop
  • Kerri Cahoy
  • Brian Cohen
  • Clayton Crail
  • Lidia Cucurull
  • Pratik Dave
  • Michael DiLiberto
  • Neal Erickson
  • Chad Fish
  • Shu-peng Ho - NCAR/UCAR
  • R. Leslie
  • Adam Milstein
  • Idahosa Osaretin
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