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.
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 short-wavelength 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 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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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL) detailing a software system designed to generate tropospheric corrections for Interferometric Synthetic Aperture Radar (InSAR) using data from GPS and weather models. This initiative is part of a NASA Advanced Information Systems Technology project aimed at improving the accuracy of satellite measurements by addressing atmospheric effects, particularly tropospheric delays.
The research leverages a network of approximately 1,200 continuous, permanent GPS stations in western North America, which are regularly analyzed to produce Earth Science Data Records, including position time series, velocities, and strain. A key component of this analysis is the estimation of Zenith Troposphere Delay (ZTD), which is crucial for creating accurate tropospheric maps. These maps are intended to reduce atmospheric artifacts in InSAR interferograms, thereby enhancing the quality of the data obtained from satellite observations.
The document outlines the integration of GPS estimates with water vapor data from weather models, specifically the NOAA North American Mesoscale (NAM) analysis. This combination allows for a dataset with uniform spatial resolution, which is essential for resolving short-wavelength atmospheric features that GPS data alone may not adequately capture.
The software system aims to provide the InSAR community with tropospheric delay correction maps, which can significantly improve the precision of measurements related to surface deformation and other geophysical phenomena. The document also includes references to various studies and technical papers that support the methodologies employed in this research.
Additionally, the document emphasizes the collaborative nature of the project, involving researchers from JPL and the Scripps Institution of Oceanography. It highlights the importance of this work in advancing our understanding of atmospheric impacts on satellite data and its potential applications in various scientific and commercial fields.
Overall, this Technical Support Package serves as a comprehensive overview of the ongoing efforts to enhance the accuracy of InSAR measurements through innovative software solutions that integrate GPS and weather model data, ultimately contributing to advancements in Earth science research.
