GPS based three-dimensional ionospheric monitoring: procedure and asessment

Kurzfassung

Integrated TEC measurements derived from ground- and space-based GPS observations are used to image the ionospheric electron density distribution through threedimensional tomographic reconstruction. Here, the reconstruction procedure is presented, that has been applied for ionospheric mapping especially during perturbed geomagnetic conditions. The monitoring technique including tomographic algorithm and external constraints is described and discussed in detail. The procedure is based on an iterative MART algorithm and is initialised by a combined IRI/GCPM model. Input data are GPS TEC measured from ground-based networks as well as from the scientific Low Earth Orbiting (LEO) satellite CHAMP. The problem of spaceborne GPS instrumental biases is addressed, and the approach applied for bias estimation by using calibrated zenith antenna TEC data is presented. Statistical validations of tomographic results with independent data are shown.