IONEX

An IONEX (IONosphere Map EXchange) file is a standardized ASCII format developed to facilitate the exchange of global ionospheric maps among various institutions and researchers. These maps represent the Total Electron Content (TEC) of the ionosphere, which is crucial for correcting ionospheric delays affecting GNSS signals.

IONEX content

IONEX files provide global grids of TEC values, typically measured in TEC units (1 TECU = 10¹⁶ electrons/m²). These grids enable users to model and correct ionospheric delays in GNSS applications.

The format supports time series of TEC maps, allowing for the representation of the ionosphere’s temporal variations. The temporal resolution can vary, depending on the data provider’s specifications.

Each IONEX file contains metadata detailing the generation method, time coverage, mapping function used, and the institution responsible for the data.

External references

For a detailed specification of the IONEX format, refer to the official IGS documentation: