Solar Flare and Radio Burst Effects on GNSS Signals and the Ionosphere During September 2017

• Autor(a) principal: de Paula, Eurico R.
• Data de Publicação: 2022
• Outros Autores: Martinon, André R. F., Carrano, Charles, Moraes, Alison O., Neri, José A. C. F., Cecatto, José R., Abdu, Mangalathayil A., Neto, Acácio C., Monico, João F. G. [UNESP], da Costa Silva, Weverton [UNESP], Vani, Bruno C., Batista, Inez S., Mendes, Odim, de Souza, Jonas R., Silva, André L. A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1029/2021RS007418; http://hdl.handle.net/11449/246269
• topic: GNSS signal fades; positioning errors; solar flare; solar radio burst

Strong solar flare events can occur even during the decay phase of the solar cycle. During these events concurrent increases in the X-ray and Enhanced UV (EUV) fluxes and solar radio bursts (SRBs) can be observed. The SRBs cover a large range of frequencies including the L band, giving rise to signal fades in the GNSS carrier-to-noise ratio and fluctuations in its amplitude and phase. The increases in the X-ray, UV, and EUV fluxes cause increase in the ionospheric D, E, and F region electron densities. The aim of this work is to analyze the effects in the GNSS signal, in the ionosphere and in the magnetic field H component of the X9.3 and X1.3 solar flares that occurred on 06 and 07 September 2017, respectively. Data from a network of six GNSS receivers, two magnetometers, and four Digisondes are used in the analysis. Fades of about 5 and 10 dB were observed in the signals of GNSS L1 and L2/L5 frequencies, respectively. Significant positioning errors, were observed for the strongest X9.3 flare. A sudden increase in Total Electron Content with the rates of 2.5–5.0 TECU/min was observed. An increase in the E layer density gave origin to an increase in the Equatorial Electrojet intensity, whose signatures were observed in the H component of two magnetometers. Another observed effect was the ionospheric D region density increase that caused disruption in the Digisonde signal. As a consequence of the described effects, GNSS receivers may fail to produce accurate navigation solution.