Model assisted inversion of GNSS occultation data

Abstract

The classical inversion of occultation data assumes spherical symmetry. Of course in the ionosphere the electron density depends not only on height but also on the geographic coordinates. Projection on a vertical “reconstruction plane” gives dependence of electron density on height and on a horizontal coordinate. Linear horizontal gradients have no influence on inversion results. However, nonlinear gradients (e.g. troughs and ridges) can influence the inversion results in such a way that they differ strongly from true height profiles of electron density in the reconstruction plane.

We have developed an inversion algorithm which such data driven models constructing the electron density distribution along the occultation rays. This introduces weights into the design matrix of the inversion equation.