Tech Briefs

Software for Generating Troposphere Corrections for InSAR Using GPS and Weather Model Data

Atmospheric errors due to the troposphere are a limiting error source for spaceborne interferometric synthetic aperture radar (InSAR) imaging. This software generates tropospheric delay maps that can be used to correct atmospheric artifacts in InSAR data. The software automatically acquires all needed GPS (Global Positioning System), weather, and Digital Elevation Map data, and generates a tropospheric correction map using a novel algorithm for combining GPS and weather information while accounting for terrain.

Advanced Land Observing Satellite (ALOS) Data. At left, the original stack of 33 interferograms. Center: The stacked correction maps, showing typical distribution of moisture in the Coachella Valley, CA. At right, the corrected stacked image." class="caption" align="right">Existing JPL software was prototypical in nature, required a MATLAB license, required additional steps to acquire and ingest needed GPS and weather data, and did not account for topography in interpolation. Previous software did not achieve a level of automation suitable for integration in a Web portal. This software overcomes these issues.

GPS estimates of tropospheric delay are a source of corrections that can be used to form correction maps to be applied to InSAR data, but the spacing of GPS stations is insufficient to remove short-wavelength tropospheric artifacts. This software combines interpolated GPS delay with weather model precipitable water vapor (PWV) and a digital elevation model to account for terrain, increasing the spatial resolution of the tropospheric correction maps and thus removing shortwavelength tropospheric artifacts to a greater extent. It will be integrated into a Web portal request system, allowing use in a future L-band SAR Earth radar mission data system. This will be a significant contribution to its technology readiness, building on existing investments in in situ space geodetic networks, and improving timeliness, quality, and science value of the collected data.

This work was done by Angelyn W. Moore, Frank H. Webb, Evan F. Fishbein, Eric J. Fielding, Susan E. Owen, and Stephanie L. Granger of Caltech; Fredrik Björndahl and Johan Löfgren of Chalmers University of Technology; and Peng Fang, James D. Means, Yehuda Bock, and Xiaopeng Tong of UC San Diego’s Scripps Institution of Oceanography for NASA’s Jet Propulsion Laboratory.

This software is available for commercial licensing. Please contact Dan Broderick at This email address is being protected from spambots. You need JavaScript enabled to view it. . NPO-48556

This Brief includes a Technical Support Package (TSP).

Software for Generating Troposphere Corrections for InSAR Using GPS and Weather Model Data (reference NPO-48556) is currently available for download from the TSP library.

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