author = "Becker-Guedes, F{\'a}bio and Carmo, Carolina de Sousa do and 
                         Camargo, Paulo O. and Monico, Jo{\~a}o F. Galera and Candido, 
                         Cl{\'a}udia Maria Nicoli",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Universidade Estadual 
                         Paulista (UNESP)} and {Universidade Estadual Paulista (UNESP)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "GNSS derived ionospheric TEC observed through different TEC 
                         calibration techniques in the brazilian sector",
            booktitle = "Proceedings...",
                 year = "2017",
         organization = "AGU Fall Meeting",
             abstract = "Global Navigation Satellite System (GNSS) is becoming a reliable 
                         tool for use in air navigation systems. Its use as the main 
                         technology for determination of airplanes positioning has various 
                         economic and logistic benefits but it depends strongly on the 
                         ionospheric layer influences. The Brazilian sector ionosphere, 
                         mainly over the equatorial ionization anomaly (EIA), presents 
                         remarkable errors in the GNSS signal as compared to North America 
                         and Europe. In order to study the total electron content 
                         latitudinal variation of the Brazilian ionosphere we used a pair 
                         of GNSS receivers on the ground, one located in the equatorial 
                         region (Sao Luis) and other in the southern crest of the EIA 
                         (Cachoeira Paulista), to collect the GNSS observables and 
                         calculate the vertical TEC using different methods that has proven 
                         to work well to describe the ionospheric behavior in the North 
                         America and in Europe. We compared this results with a modified 
                         Nagoya TEC calculation method used by the EMBRACE (Estudo e 
                         Monitoramento BRAsileiro do Clima Espacial - Brazilian Study and 
                         Monitoring of Space Weather) program. This work intends to follow 
                         the performance of different TEC tuning methods to evaluate the 
                         spurious effects of the ionospheric EIA gradients in the TEC 
                         determination under typical conditions of the low-latitudes 
                         ionosphere in the Brazilian sector. The calculated TEC under 
                         different solar cycle conditions, geomagnetic activity, and 
                         seasonal variations show deviations in the performance of each 
                         method and stress the importance of well adjust the GNSS 
                         observations to local conditions in order to optimize the TEC 
                         evaluation. This study contributes to a better understanding of 
                         local GNSS signal errors in the global intent of offering 
                         conditions to improve the accuracy, integrity, availability, and 
                         continuity requirements for the use of GNSS for air navigation in 
                         South America.",
  conference-location = "New Orleans",
      conference-year = "11-15 Dec.",
             language = "en",
        urlaccessdate = "24 jan. 2021"