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Global Navigation Satellite System (GNSS) IGS Final Analysis Center (AC) Troposphere Zenith Path Delay (ZPD) product from NASA CDDIS

Metadata Updated: April 10, 2026

This derived product set consists of Global Navigation Satellite System Final Troposphere Zenith Path Delay (ZPD) Product (daily files by station) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce troposphere ZPD estimates for stations of the IGS network. The primary troposphere products generated from ground-based GNSS data are estimates of total zenith path delay and north/east troposphere gradient. Ancillary measurements of surface pressure and temperature allow the extraction of precipitable water vapor from the total zenith path delay. The IGS Troposphere Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS troposphere ZPD estimates for many of the stations in the IGS network. The final AC products consist of daily files containing data from each observing station. All ZPD solution files utilize the Solution INdependent EXchange format for combination of TROpospheric estimates (SINEX_TRO) and span 24 hours from 00:00 to 23:45 UTC.

Access & Use Information

Public: This dataset is intended for public access and use. License: See this page for license information.

Downloads & Resources

Dates

Metadata Created Date April 9, 2025
Metadata Updated Date April 10, 2026

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 9, 2025
Metadata Updated Date April 10, 2026
Publisher CDDIS
Maintainer
Identifier 10.5067/GNSS/GNSS_IGSTROPZPDAC_001
Data Last Modified 2026-04-06
Category Earth Science
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 07259395-799f-4921-89ab-586d90cb0010
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
License https://www.usa.gov/government-works
Old Spatial {"EastBoundingCoordinate":180,"NorthBoundingCoordinate":90,"SouthBoundingCoordinate":-90,"WestBoundingCoordinate":-180},"CARTESIAN"
Program Code 026:000
Source Datajson Identifier True
Source Hash c339353c1917205c885a9dce9d130c0673d2e52e54d418b3b8968ce831daeb70
Source Schema Version 1.1
Spatial
Temporal 2000-01-01/2026-03-30

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