A new method for computing absolute (unambiguous) levels of Total Electron Content (TEC) in the ionosphere and subsequently the L1 and L2 phase advances of GPS is presented, dubbed “ICON” (for its primary purpose of modeling the Ionosphere over CONus). Unlike previous computational methods, this method relies solely upon dual-frequency, ambiguous carrier phase data with no reliance on pseudo-ra...

This paper optimizes a GPS smoothing filter to minimize biases caused by ionosphere divergence during anomalous storms. Ionospheric storms represent the most severe threat to high-integrity differential GPS systems, such as Ground-Based Augmentation Systems (GBAS). Substituting the optimized filter for the Hatch Filter typically used in GBAS reduces ionosphere divergence bias by over 10% for a ...

Generalization of radio holographic method for 3-dimensional case is presented. Application of this method to analysis of radio occultation data gives high vertical resolution and accuracy in estimating physical parameters of the ionosphere and atmosphere and allows recovering vertical temperature gradients and wave structures in the atmosphere and in the ionosphere.

Strong ionosphere storms are the most-threatening potential fault mode for the Local Area Augmentation System (LAAS). Multi-frequency GPS techniques are known to be an effective means of reducing or removing ionosphereinduced problems. Among those techniques, of great interest are Divergence-Free smoothing (denoted here as DFree) and Ionosphere-Free smoothing (denoted here as IFree). This paper...

The ionosphere plays a role in radio propagation that varies strongly with frequency. At extremely low frequency (ELF: 3–3000 Hz) and very low frequency (VLF: 3–30 kHz), the ground and the ionosphere are good electrical conductors and form a spherical Earth-ionosphere waveguide. Many giants of the electromagnetics community studied ELF-VLF propagation in the Earth-ionosphere waveguide, a topic ...

One can divide the existing ionospheric methods for SBAS in two categories: tomography and methods relying on the thin shell model. At first sight, tomography appears to be the right choice. Tomography reconstructs the three dimensional density of the ionosphere from the available measurements. However, there are several drawbacks to tomography: the system of equations to be solved is often und...

Spaceborne imaging of the Earth’s surface by synthetic aperture radar (SAR) may be adversely affected by the ionosphere that causes distortions of the signals emitted and received by the radar antenna. In our previous publication on the subject [SIAM J. Imaging Sci., 2 (2009) pp. 140–182], we have analyzed those distortions for the inhomogeneous ionosphere described by the cold plasma model. Ba...

Through respectively adding September DE3 tide and March DE3 tide at the low boundary of Global Coupled Ionosphere-Thermosphere-Electrodynamics Model, Institute of Geology and Geophysics, Chinese Academy of Sciences (GCITEM-IGGCAS), we simulate the influence of DE3 tide on the equinoctial asymmetry of the zonal mean ionospheric electron density. The influence of DE3 tide on the equinoctial asym...

We introduce a methodology to extract the separate contributions of the ionosphere and the plasmasphere to the vertical total electron content, without relying on a fixed altitude to perform that separation. The method combines two previously developed and tested techniques, namely, the retrieval of electron density profiles from radio occultations using an improved Abel inversion technique and...