NASA ACCESS 2019 Project

Name: GNSS RO Data in the AWS Cloud

Team: Stephen Leroy (PI), Amy McVey (Lead Software Engineer), Mark Leidner, Jonathan Martin


Earth radio occultation (RO) using the transmitters of the Global Navigation Satellite Systems (GNSS), including the U.S. Global Positioning System, has become a cornerstone of climate monitoring and numerical weather prediction because of its extraordinary calibration, vertical resolution approaching 100 meters, and all-weather capability. The RO proof-of-concept mission GPS/MET flew in 1995–1997, and the continuous data set extends from 2001 through the present. Working with GNSS RO data is fraught with difficulties, including differences in retrieval as produced by independent processing centers, data formats that are heterogeneous across processing centers and among RO missions, data volume and bandwidth, and an effective means of sub-setting the data. The goal of this project to manifest all GNSS RO data ever recorded and as processed by as many independent retrieval centers as wish to contribute in uniform data formats in the AWS Open Data Registry, generate a database for easy searching and sub-setting of the data, keep that repository current, and educate the general public about AWS cloud computing. This will enable researchers anywhere to perform research with GNSS RO data with far greater ease than in the past, and it will nudge the scientific community in the direction of cloud computing for research purposes.

This project of the NASA Advancing Collaborative Connections for Earth System Science 2019 Program (NASA ACCESS 2019).


  • The project commenced on January 1, 2021. GNSS RO data contributed by UCAR and ROMSAF are live in the AWS Open Data Registry here.
  • RO data as published by UCAR are current. COSMIC-2 RO data has yet to be manifested, though.
  • RO data as produced by the ROM SAF are current, but only for RO data from the COSMIC-1 and Metop missions. The ROM SAF data products that are manifested are the CDR and the ICDR.
  • The live version is v1.1.


The GNSS RO data repository in the AWS Open Data Registry is found here.

A GitHub support page with documentation, useful utilities, and tutorial demonstrations is found here.


The project will conduct workshops to introduce the scientific public on GNSS RO data in the AWS Open Data Registry and how to use the repository with AWS cloud computing. The dates, times and places are

September 13, 2022, from 19:00 to 21:00 (Central European Time), in Leibnitz, Austria, as part of the OPAC-7 / IROWG-9 workshop. More information here.