GNSS IGS Ionosphere VTEC Maps: Global Daily Vertical Electron Content

NASA CDDIS provides daily Global Navigation Satellite System (GNSS) Ionosphere Vertical Total Electron Content (VTEC) maps with a spatial resolution of 5 degrees in longitude and 2.5 degrees in latitude, and a temporal resolution of 2 hours in Universal Time. These derived products, generated by International GNSS Service (IGS) Analysis Centers, also include Delay Code Bias (DCB) values for satellites and ground receivers. The dataset incorporates data from multiple global constellations, including GPS, GLONASS, Galileo, Beidou, QZSS, and IRNSS, since 2011.

Use Cases

• Modeling ionospheric delay for high-precision GNSS positioning based on the provided VTEC maps.
• Studying space weather events and ionospheric disturbances using the global, time-series VTEC data.
• Calibrating satellite and receiver hardware biases (DCBs) for GNSS network analysis.
• Validating and assimilating ionospheric data into numerical weather prediction and climate models.

Strengths

• Data incorporates observations from a global multi-constellation GNSS network since 2011.
• Products have defined high-resolution spatial (5° lon, 2.5° lat) and temporal (2-hour) grids.
• Cross-platform presence on NASA and government portals indicates established importance and curation.

Limitations

• Column names and specific data structure are not documented in the provided metadata.
• Sources conflict on product latency (1-2 days for 'Rapid' vs. 3-7 days for 'Final') and product type ('Rapid' vs. 'Final'), creating ambiguity.
• Dataset size, row counts, and detailed license terms are not specified.

Provenance

Source

NASA Crustal Dynamics Data Information System (CDDIS), derived from International GNSS Service (IGS) Analysis Centers.

Collection Method

Derived from GNSS observations retrieved from a global ground receiver network and processed by IGS Analysis Centers to generate VTEC maps.

Time Range

Data includes constellations added since 2011; specific start date for the VTEC product series is not provided.

Freshness

Last updated on 2026-04-10 according to datagov metadata.

Geography

Global coverage.