The ionosphere causes the most difficult error to mitigate in Satellite Based Augmentation Systems (SBAS). The problem has been solved for the mid latitude regions using the thin shell approximation. There, it is very accurate on quiet days and allows the augmentation system so send the information in a two dimensional grid with a five by five degree resolution. However, even during quiet days,...

New opportunities for the refinement of ionospheric modelling and reduction of the ionospheric error in GPS measurements arise since a third-frequency will be introduced for the modernised GPS system. This paper investigates theoretical models of the ionospheric refractive error. A triple-frequency method of correcting the 1 and 2 order ionospheric refraction is presented and a triple-frequency...

Ionospheric delay is one of the largest and most variable sources of error for Ground-Based Augmentation System (GBAS) users because inospheric activity is unpredictable. Under normal conditions, GBAS eliminates ionospheric delays, but during extreme ionospheric storms, GBAS users and GBAS ground facilities may experience different ionospheric delays, leading to considerable differential errors...

A major error component of Global Positioning System (GPS) is the ionospheric delay. Ionopspheric error can be reduced by a dual frequency receiver using a linear combination technique that can not be applied with a single frequecy receiver. However, an accurate ionospheric error modeling for single-frequency receiver is required. Due to the nonlinearity of the ionospheric error, a highly nonli...

In this contribution the impact of a presumed presence or absence of the ionospheric delays on the quality of the least-squares ambiguities is analysed. The spatial correlation and the time correlation of the ionospheric delays are captured in an a priori ionospheric variance matrix. It is shown how the size and shape of the ambiguity search space is a€ected by the use of these a priori ionosph...

Ionized by solar radiation, the ionosphere causes a phase rotation or time delay to trans-ionospheric radio waves. Reconstruction of ionospheric electron density profiles with global navigation satellite system (GNSS) observations has become an indispensable technique for various purposes ranging from space physics studies applications. This paper conducts comprehensive review on development vo...

The long-term goal of our research is to develop a reliable and accurate global ionospheric weather monitoring and forecast system which can serve as a prototype for an operational system. To achieve this goal, we are developing and validating advanced data assimilation techniques to analyze diverse sources of ionospheric measurements. The assimilation of ionospheric measurements into mature fi...

When interpreting GNSS observations of ionospheric scintillation, it is instructive to distinguish between the separate goals of characterizing the GNSS signal fluctuations and characterizing the disturbed ionospheric medium that produces the scintillations. The statistics of GNSS signal fluctuations are of primary interest for GNSS tracking loop analysis and design studies intended to quantify...

Ionospheric scintillation occurs mainly at high and low latitude regions of the Earth and may impose serious degradation on GNSS (Global Navigation Satellite System) functionality. The Brazilian territory sits on one of the most affected areas of the globe, where the ionosphere behaves very unpredictably, with strong scintillation frequently occurring in the local postsunset hours. The correlat...