The ionosphere is a major source of systematic errors in positioning and navigation by GNSS (Global Navigation Satellite System), due to the observables be affected by various ionospheric conditions due to changes of the Space Weather. Develop new algorithms and improve existing ones, in order to minimize the effects of the ionosphere, especially in GNSS techniques, is one of the main aspects of the Space Geodesy. Among the GNSS techniques stand out the SBAS (Satellite-Based Augmentation System) and the GBAS (Ground-Based Augmentation System), used in aviation in support of the approach and landing phases of aircrafts. The GBAS has the ability to correct most errors involved in the pseudorange near an airport, provided the ionospheric layer are of non-disturbed behavior. However, depending on the solar ionization flow, geomagnetic activity, sunspot cycle, zenith angle of the sun, local time and geographic location, the ionosphere can suffer serious disturbances, thus providing a threat to the integrity of the GBAS. This way, investigations of the effects of systematic errors due to ionospheric layer in GBAS have been objects of study of many researchers and air institutions a few years ago. Ionospheric threat models were developed especially for the northern hemisphere, specifically for the North American territory, whose ionosphere is more stable, unlike Brazil, located in low latitude ionospheric region, which has unique conditions from the rest of the Earth, such as occurrence of Equatorial Ionization Anomaly (EIA), ionospheric bubbles, ionospheric scintillation and Magnetic Anomaly of the South Atlantic. The increasing demand for domestic and international flights in Brazil, along with the implementation of a GBAS in the country through the Department of Airspace Control (DECEA) sparked interest in the study of a threat model. Thus, the research project proposes the development and evaluation of an ionospheric threat model for GBAS in Brazil, with emphasis on the effects of the EIA, ionospheric irregularities and ionospheric scintillation, as well as research and analysis of the benefits in the use of GLONASS and Galileo signs and new GPS L5 carrier in the GBAS system, given that currently only pseudorange measurements for GPS L1 are used. For this will be used GNSS data of Brazilian active networks for the development of the model, as well as data from the only GBAS station installed in Brazil, located in the Antonio Carlos Jobim International Airport (Galeao), Rio de Janeiro/RJ, and others that can be installed throughout the project, to evaluate the system.
News published in Agência FAPESP Newsletter about the scholarship: