ION GPS 2001
Salt Lake City
September 11-14, 2001
Since the late 1980’s various research groups have been investigating the behaviour of the ionosphere using Global Positioning System (GPS) data. These investigations are based on the total electron content (TEC) measurements derived from dual-frequency GPS observations taking advantage of the dispersive nature of the ionospheric medium. Currently, there is a large number of GPS receivers in continuous operation worldwide. Even though large in number, these stations are unevenly distributed, being situated mostly in the northern hemisphere region. The relatively smaller number of GPS receivers in the southern hemisphere, and consequently the reduced number of available TEC measurements, causes ionospheric modelling to be less accurate for this region. GPS data from the Brazilian Network for Continuous Monitoring by GPS (RBMC) have been used for the first time to obtain TEC values in order to monitor the ionospheric behaviour in the South American region. For this task, we are using the University of New Brunswick (UNB) Ionospheric Modelling Technique which uses a spatial linear approximation of the vertical TEC above each station using stochastic parameters in a Kalman filter estimation to describe the local time and geomagnetic latitude dependence of the TEC. The utilisation of the RBMC GPS data to monitor the ionosphere over South America can help us to obtain a better understanding of many important low latitude ionospheric phenomena, such as the Appleton Equatorial Anomaly and the South Atlantic Anomaly as well as more accurate and representative regional and global ionospheric models. Furthermore, the effect of geomagnetic storms on the equatorial and low-latitude ionosphere is discussed, as well as the integrity of GPS data obtained in equatorial and low-latitude regions.
Fedrizzi, Mariangel, Langley, Richard B., Komjathy, Attila, Santos, Marcelo C., de Paula, Eurico Rodrigues, Kantor, Ivan Jelinek, "The Low-latitude Ionosphere: Monitoring its Behaviour with GPS," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2468-2475.