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Ionospheric S4 Scintillations from GNSS Radio Occultation (RO) at Slant Path
oleh: Dong L. Wu
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2020-07-01 |
Deskripsi
Ionospheric scintillation can significantly degrade the performance and the usability of space-based communication and navigation signals. Characterization and prediction of ionospheric scintillation can be made from the Global Navigation Satellite System (GNSS) radio occultation (RO) technique using the measurement from a deep slant path where the RO tangent height (<i>h<sub>t</sub></i>) is far below the ionospheric sources. In this study, the L–band S4 from the RO measurements at <i>h<sub>t</sub></i> = 30 km is used to infer the amplitude scintillation on the ground. The analysis of global RO data at <i>h<sub>t</sub></i> = 30 km shows that sporadic–E (Es), equatorial plasma bubbles (EPBs), and equatorial spread–F (ESF) produce most of the significant S4 enhancements, although the polar S4 is generally weak. The enhanced S4 is a strong function of local time and magnetic dip angle. The Es–induced daytime S4 tends to have a negative correlation with the solar cycle at low latitudes but a positive correlation at high latitudes. The nighttime S4 is dominated by a strong semiannual variation at low latitudes.