Long-term impact of ionospheric scintillations on kinematic precise point positioning: seasonal and solar activity dependence over Indian low latitudes

• Published in: GPS solutions Vol. 27; no. 1; p. 40
• Main Authors: Yousuf, M., Dashora, N., Sridhar, M., Dutta, G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2023; Springer Nature B.V
• Subjects: Amplitudes; Atmospheric Sciences; Automotive Engineering; Climatology; Earth and Environmental Science; Earth Sciences; Electrical Engineering; Fluctuations; Geophysics/Geodesy; Global positioning systems; GPS; Influences of Space Weather on GNSS Operations; Kinematics; Original Article; Perturbation; Plasma bubbles; Position errors; Solar activity; Solar cycle; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Variability; Solar activity; Equatorial plasma bubbles; Extreme events; Low latitudes; Kinematic precise point positioning; Ionospheric scintillations; Geomagnetic storm
• ISSN: 1080-5370; 1521-1886
• DOI: 10.1007/s10291-022-01378-1

The lengthiest GPS observations from a reference station during 2002–2018 and a colocated scintillation monitoring receiver during 2013–2018 at Hyderabad, India, are used to analyze the degradation in kinematic precise point positioning (KPPP) due to ionospheric irregularities. The GipsyX software is employed to estimate the KPPP of the reference station and the residuals for each coordinate are computed against the monthly mean values of the daytime observations. The results establish the long-term variability of the residuals of KPPP under the climatological and event-specific effect of the post-sunset equatorial plasma bubbles (EPBs). The extreme post-sunset fluctuations in the residuals during a few quiet and disturbed nights obtained from the 18 years of continuous observations are emphasized. The outstanding and persistent patterns in the residuals are majorly found during extended post-sunset hours with striking seasonal contrast. The large and rapid fluctuations in the residuals are found to exhibit long-term day-to-day, seasonal, and solar cycle variations, which correspond to the occurrence of the amplitude and phase scintillations. Thus, uniquely, the colocated observations of scintillations corroborate the impact of the simultaneously affected number of satellites (S4 index > 0.17) and indicate the possibility of cycle slips eventually affecting the KPPP solutions. The seasonal climatology of the scintillations is shown to translate over the 3-D position error, which modulates with change in the solar F10.7 cm flux. This study, thus probably for the first time, reports the long-term effect of solar cycle variability on the amplitude of perturbations in KPPP for the solar cycles 23 and 24.