Method for Determining an Electron Density Distribution in the Earth's Atmosphere

A method for determining a four-dimensional ionosphere model of an electron distribution in the Earth's atmosphere is disclosed, which is used to correct runtime measurements of signals emitted by satellites, for position determinations by means of signal receivers. The method comprises: a) defining at least one distribution function based on at least one function parameter which is suitable to describe a distribution of electrons over the height of the Earth's atmosphere; b) receiving data from a plurality of runtime measurements by means of a plurality of movable dual-frequency signal receivers, in order to determine parameters that are representative for a total quantity of electrons along a signal transmission path from a satellite to a dual-frequency signal receiver; c) determining location-dependent and time-dependent function parameters for the distribution function at least by means of the parameters; and d) providing the function parameters determined in step c) as a four-dimensional ionosphere model.