Abel ionospheric inversion technique and its error analysis

Currently, GNSS-LEO ionospheric radio occultation (IRO) is a new and powerful technique in probing ionosphere. In order to eliminate the effect from the topside ionosphere above LEO, the Calibrated TEC inversion technique retrieves electron density profiles utilizing non-occultation side measurements. In this paper, a new technique is firstly proposed based on the Epoch Difference, and then the two techniques are applied in the inversion of simulated data, subsequently some conclusions can be drawn from the inversion results and its error analysis: the inversion results derived from the Epoch Difference inversion technique show better performance than those derived from the Calibrated TEC inversion technique; no matter which inversion technique is used, the inversion results at the higher orbits (~800 km) are better than those at the lower orbits (~500 km). The lower the profile altitudes, the lower the precision of inversion; the inversion errors are significant during 8-18 (local time), and are mainly located between -30° and 30° (magnetic latitude).