Radio Tomography of the Ionosphere: Analysis of an Under-determined, Ill-posed Inverse Problem, and Regional Application
Garcia, R.¹; Crespon, F.^2
1Laboratoire de Dynamlque Terrestre et Planétaire, Observatoire Midi-Pyrénées; ²Noveltis

After an analysis of the forward and inverse problems of radio tomography, a time varying three-dimensional imaging method of the ionosphere through GPS slant TEC data is described, justified and applied at regional.

Our approach is based on local basis parametrisation of electron density, and constrained by NeQuick ionosphere model and its space gradients.

Our inversion scheme is fundamentally different from the data assimiliation approach because it is not based on a physical ionosphere model.

However, because our imaging method is able to retreive small scale ionosphere features in properly resolved volumes, these two approaches appear to be very complementary.

The preliminary results obtained with european GPS receiver data validate the method and its stability, even if a lot of improvements are still possible on the algorithm and a careful validation of inverted models by independent data is still necessary.