Options
Nottingham Geospatial Institute, University of Nottingham, Nottingham, UK
2 results
Now showing 1 - 2 of 2
- PublicationOpen AccessPerformance of ionospheric maps in support of long baseline GNSS kinematic positioning at low latitudes(2016)
; ; ; ; ; ; ; ; ; ;; ; ;Ionospheric scintillation occurs mainly at high and low latitude regions of the Earth and may impose serious degradation on GNSS (Global Navigation Satellite System) functionality. The Brazilian territory sits on one of the most affected areas of the globe, where the ionosphere behaves very unpredictably, with strong scintillation frequently occurring in the local postsunset hours. The correlation between scintillation occurrence and sharp variations in the ionospheric total electron content (TEC) in Brazil is demonstrated in Spogli et al. (2013). The compounded effect of these associated ionospheric disturbances on long baseline GNSS kinematic positioning is studied in this paper, in particular when ionospheric maps are used to aid the positioning solution. The experiments have been conducted using data from GNSS reference stations in Brazil. The use of a regional TEC map generated under the CALIBRA (Countering GNSS high-Accuracy applications Limitations due to Ionospheric disturbances in BRAzil) project, referred to as CALIBRA TEC map (CTM), was compared to the use of the Global Ionosphere Map (GIM), provided by the International GNSS Service (IGS). Results show that the use of the CTM greatly improves the kinematic positioning solution as compared with that using the GIM, especially under disturbed ionospheric conditions. Additionally, different hypotheses were tested regarding the precision of the TEC values obtained from ionospheric maps, and its effect on the long baseline kinematic solution evaluated. Finally, this study compares two interpolation methods for ionospheric maps, namely, the Inverse Distance Weight and the Natural Neighbor.250 34 - PublicationOpen AccessGPS phase scintillation at high latitudes during geomagnetic storms of 7–17 March 2012 – Part 2: Interhemispheric comparison(2015)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Prikryl, P.; Geomagnetic Laboratory, Natural Resources Canada, Ottawa, ON, Canada ;Ghoddousi-Fard, R.; Canadian Geodetic Survey, Natural Resources Canada, Ottawa, ON, Canada ;Spogli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Mitchell, C. N.; Department of Electronic and Electrical Engineering, University of Bath, Bath, UK ;Li, G.; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China ;Ning, B.; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China ;Cilliers, P. J.; Space Science Directorate, South African National Space Agency, Hermanus, South Africa ;Sreeja, V.; Nottingham Geospatial Institute, University of Nottingham, Nottingham, UK ;Aquino, M.; Nottingham Geospatial Institute, University of Nottingham, Nottingham, UK ;Terkildsen, M.; IPS Radio and Space Services, Bureau of Meteorology, Haymarket, NSW, Australia ;Jayachandran, P. T.; Physics Department, University of New Brunswick, Fredericton, NB, Canada ;Jiao, Y.; Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO, USA ;Morton, Y. T.; Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO, USA ;Ruohoniemi, J. M.; Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA ;Thomas, E. G.; Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA ;Zhang, Y; Johns Hopkins University Applied Physics Lab, Laurel, MD, USA ;Weatherwax, A. T.; Department of Physics and Astronomy, Siena College, Loudonville, NY, USA ;Alfonsi, Lu.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;De Franceschi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Romano, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7–17 March 2012 caused geomagnetic storms that strongly affected high-latitude ionosphere in the Northern and Southern Hemisphere. GPS phase scintillation was observed at northern and southern high latitudes by arrays of GPS ionospheric scintillation and TEC monitors (GISTMs) and geodetic-quality GPS receivers sampling at 1 Hz. Mapped as a function of magnetic latitude and magnetic local time (MLT), the scintillation was observed in the ionospheric cusp, the tongue of ionization fragmented into patches, sun-aligned arcs in the polar cap, and nightside auroral oval and subauroral latitudes. Complementing a companion paper (Prikryl et al., 2015a) that focuses on the highlatitude ionospheric response to variable solar wind in the North American sector, interhemispheric comparison reveals commonalities as well as differences and asymmetries between the northern and southern high latitudes, as a consequence of the coupling between the solar wind and magnetosphere. The interhemispheric asymmetries are caused by the dawn–dusk component of the interplanetary magnetic field controlling the MLT of the cusp entry of the storm-enhanced density plasma into the polar cap and the orientation relative to the noon–midnight meridian of the tongue of ionization.716 565