Acurácia do posicionamento absoluto GPS com correção da ionosfera advinda de mapas ionosféricos globais e regionais

Abstract

The effect caused by the ionosphere in the GPS signal is one of the most important in the geodetic coordinate estimation process, mainly for data collected by single frequency receivers, if a not consistent ionospheric model is available. For such case, one can currently apply the ionospheric corrections provided by the Klobuchar model and from Global or Regional Ionosphere Maps. The latter have been investigated by the scientific community in recent years. In this this paper, attention is driven to the LPIM (La Plata Ionospheric Model) developed at the University La Plata and made available within the SIRGAS project context. Thus, this paper presents the evaluation of the absolute positioning accuracy with ionospheric corrections coming from the GIM and LPIM. It was accomplished PPP processing by using only GPS code data collected by Brazilian RBMC stations. The coordinates estimation was carried out in an epoch by epoch basis and the solutions were compared with ground truth estimated in the SIRGAS-CON network providing the daily RMS with time series generation for the complete year of 2013. Based on the improvement produced by the application of the LPIM it is proposed the stochastic model modification for the adjustment considering that only the functional model is affected by ionospheric corrections coming from distinct models.