Ionospheric tomography by using diverse data sources

The computerized ionospheric tomography (CIT) is an under-determined, ill-posed inverse problem. The limited-angle geometry and sparse receivers lead incomplete information in measurements, which affect the precision of the CIT imaging, especially in the vertical dimension. This paper puts forward a new method by combining vertical and oblique sounding data with the total electron content (TEC) retrieved from an assumed tri-band beacon of a planned Chinese satellite for seismological studies transmitting VHF, UHF and L-band frequencies. A ground-based high-resolution ionospheric observation network (GHRION) has been built in northern China in April, 2009. Based on this ground network and the planned satellite, high-resolution ionospheric structures will be reconstructed in real time, for helping monitoring the ionospheric precursors of earthquakes over several large seismic belts in northern China. The initial of the iterative is specified by real sounding data, so it slightly deviates from the real electron density distribution and the CIT result is in high precision. The numerical simulations show that electron density images reconstructed from TEC using three-frequency technique are significantly improved after combining real observation data of the ground-based vertical and oblique ionograms. The results in this paper will help to ensure that the measurements to be made by this solid network will yield their potential.