Electron Density

Electron density describes the number of free electrons per unit volume in a plasma, most prominently in the Earth’s ionosphere. In geodesy, electron density is a key parameter because it directly affects the propagation of radio signals used by space-geodetic techniques such as GNSS, DORIS, and VLBI. Variations in ionospheric electron density cause signal delays and phase shifts, influencing positioning accuracy and timing. Geodetic observations are therefore used both to correct ionospheric effects and to monitor the ionosphere as part of Earth system research and space weather studies.