A GPS based three-dimensional ionospheric imaging tool: Process and assessment

A Multiplicative Algebraic Reconstruction Technique (MART) assimilation process of calibrated ground-based and occultation GPS TEC data into combined IRI/GCPM model data is described. The resulting electron density fields are assessed with in situ records. An improvement of the electron density estimations by IRI/GCPM of 27.25% at northern high latitudes is obtained through the assimilation of GPS data. A specification of NmF2 and hmF2 within a mean bias of only 8.5 × 1010 m−3 and −6.1 km, respectively, is achieved in comparison with soundings of seven European ionosondes.