Análise preliminar dos impactos do uso de mais de um sistema GNSS no posicionamento preciso.

To obtain precise coordinates in Satellite Geodesy, relative positioning and precise point positioning (PPP) techniques are used. In this work a preliminary analysis of the impacts on Dilution of Precision (DOP) and positioning accuracy caused by tracking several GNSS, using single and double frequency receivers, considering two- and 24-hour sessions in two time periods of the year, and, as such, subject to different ionospheric conditions, is presented. These analyses have been performed based on data available from the Brazilian Network for Continuous Monitoring of GNSS (RBMC) and the Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS). The processing results have been obtained using the GNSS Planning Online, IBGE-PPP and RTKLIB software/services, which have confirmed the accuracy improvement in relative and PPP positioning when using more GNSS observations. Another factor which contributes to this improvement is a more favourable satellite constellation used in the solutions. The solar activity, time of year and tracking period of the day also directly impact the quality of positioning. [ABSTRACT FROM AUTHOR]