Abstract:
Global Navigation Satellite System (GNSS) and international telecommunications
critical to a modern technological world are frequently disrupted by the Earth’s iono sphere. Trans-ionospheric satellite navigation links operate primarily at L band and are
frequently subject to severe degradation of performances arising out of ionospheric ir regularities. As human society has become heavily dependent on GNSS services, timely
and accurate space weather characterization and forecasts are needed. This analysis
investigates the frequency dependence of ionospheric scintillation on GNSS signals. By
examining data from multiple GNSS frequencies, the study aims to understand how
scintillation affects different signal frequencies and to identify patterns in scintillation
behavior. The data derived from high-rate Global Navigation Satellite System (GNSS)
receiver located at Bahir Dar University, Ethiopia, were used to analyze the effect of
ionospheric scintillation on GNSS signals with different frequency bands. The results
are presented for data recorded by GNSS receiver during the last solar maximum in
2015. Observation data from two GNSS receiver stations msbd01 and msbd02 were
used to investigate the characteristics of ionospheric scintillation across different fre quency bands for GPS, GLONASS and Galileo constellations. The results showed
that the amplitude scintillations were observed during local sunset. The influence of
ionospheric scintillation on different frequency GNSS signals is also different. During
strong scintillation events, there is a reduction in the correlation coefficient between
different frequency signals, indicating that the ionospheric irregularities affect different
frequencies differently. It is found that the higher frequencies experienced less severe
amplitude scintillation compared to lower frequency signals during scintillations. We
also used continuous wavelet transform to detect the ionospheric plasma bubble causing
scintillations. This work would be helpful for understanding the features of GNSS
amplitude scintillations over the equatorial regions. The findings will help improve
GNSS receiver performance and develop effective mitigation strategies. Moreover,
these kinds of investigations are helpful for developing new algorithms to forecast
ionospheric scintillations over such regions.