Accuracy assessment of Precise Point Positioning with multi-constellation GNSS data under ionospheric scintillation effectsHaroldo Antonio Marques, Heloísa Alves Silva Marques, Marcio Aquino, Sreeja Vadakke Veettil and João Francisco Galera MonicoJ. Space Weather Space Clim., 8 (2018) A15DOI: https://doi.org/10.1051/swsc/2017043