Study on the Calculation Strategies of Ionospheric Scintillation Index ROTI from GPS

Abstract

Ionospheric irregularities which is related with irregular plasma or density variations in the ionosphere can cause rapid fluctuations in amplitude and phase of Global Navigation Satellite Systems (GNSS) signals. In order to get a better strategy for ionospheric scintillation monitoring with GNSS observations, in this article, we studied the capability of ROTI (Rate of TEC Index) from different calculation strategies in reflecting the ionospheric scintillation by comparing their correlation with amplitude scintillation index in low-latitude region of China with the data from CMONOC (Crustal Movement Observation Network of China). The results indicate that various samplings all can show strong consistency with scintillation index S4 in overall and higher samplings is followed with higher correlations with S4. The contribution of calculation time interval of ROTI to the correlation with S4 depends on sampling rate. The analysis also indicates that the curve of ROTI tends to be more smooth as the time interval of calculation of ROTI increases and the ROTI in shorter time interval of calculation, e.g., 1 minute, can reveal more details compared with the curve of scintillation indices. Moreover, the ROTI maps retrieved from CMONOC can reflect the temporal and spatial evolution of ionospheric irregularities in the region of China, which is helpful to provide warning for GNSS users.