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Abstract

The ionospheric delay is the main error sources for one frequency GNSS users. Models have been developed to reduce such effects and improve the quality of the positioning. However, when some irregularities occur in the ionosphere, even the users of multi frequency receivers, with multi-constellation, may suffer degradation in the quality of the positioning. At low latitude region, ionospheric scintillation (IS), that occurs mainly from September to March, and stronger during the period of high solar cycle, affects the performance of GNSS applications that require real time navigation. IS occurs in the Earth's ionosphere and can cause variations in the amplitude and phase of GNSS signals. In particular, it is an issue impacting both the availability and the accuracy of high-precision GNSS based positioning techniques. Experiments were carried out during December 2022 and January 2023, in Presidente Prudente, Brazil, a region with high level of IS, and with a cluster of stations that provide several elements for the investigation. The aim is to assess how the use of multi-constellation considering or not the multi-frequencies available, may help in the mitigation of the IS. From the preliminary results, that will be expanded for the presentation, multiple frequencies may help to provide improvement, but attention has to be paid with the level of increasing noise in the observables and also with the dependency of requiring observables present at both frequencies, what is not always the case. The stochastic model also plays an important function and will be discussed during the presentation.