GPS Scintillations and Losses of Signal Lock at High Latitudes During the 2015 St. Patrick's Day Storm

Abstract

We investigate the Global Positioning System (GPS) amplitude and phase scintillations during a severe geomagnetic storm on 17 March 2015. The auroral oval expanded significantly due to a strongly southward interplanetary magnetic field (Bz was −25 nT). When the auroral oval was over Skibotn in northern Norway, significant enhancements in total electron content (TEC) fluctuations, amplitude, and phase scintillation were observed. The strongest amplitude and phase scintillations were observed when a TEC blob propagated across the field of view. Strong amplitude and phase scintillations were observed near the edges of the TEC blob. The European Incoherent SCATter ultrahigh frequency radar observed significant enhancement of electron density (from 0.8 × 1011 to 1.6 × 1011 m−3) near the edge of the TEC blob in the F2 region, while the E region was only slightly enhanced. This indicates that the plasma processes and instability modes, which accounted for the strong GPS scintillations, should involve the F2 region ionosphere. We also analyzed the tracking performance of the GPS receiver during strong ionospheric scintillation condition. While the receiver maintained tracking of the GPS L1 signal, the strong amplitude scintillation resulted in a power fade up to 12 dB‐Hz. Losses of lock occurred in the GPS L2 band. Both the power fade and rapid phase fluctuation should contribute to losses of lock.

Simultaneous Rocket and Scintillation Observations of Plasma Irregularities Associated With a Reversed Flow Event in the Cusp Ionosphere

“…These slopes are consistent with the result inJin and Oksavik (2018). The spectra show a power-law spectrum, and the black lines show linear fits to the spectral slopes.…”

“…The receiver can provide TEC from the dual frequency measurements of the GPS signals. In addition, the 50-Hz raw data of the amplitude and carrier phase at the GPS L1 frequency were used for calculating high-resolution (1 s) scintillation indices and 10.1029/2019JA026942 Journal of Geophysical Research: Space Physics power spectra in this study (Jin & Oksavik, 2018). In addition, the 50-Hz raw data of the amplitude and carrier phase at the GPS L1 frequency were used for calculating high-resolution (1 s) scintillation indices and 10.1029/2019JA026942 Journal of Geophysical Research: Space Physics power spectra in this study (Jin & Oksavik, 2018).…”

Polar Cap Patch Prediction in the Expanding Contracting Polar Cap Paradigm

“…However, a patch does not have to be exactly above the receiver to cause scintillations, because GPS satellites are seen in different directions and elevations, and so the patch can be observed at a different time. The same pattern was seen by Jin and Oksavik (). Additionally, there are some data gaps in the GPS TEC observations in the first panel of Figures and (white areas).…”

“…We observed significant scintillations at Ny-Ålesund at 20:30 UT, which agrees well with our prediction. The VTEC observations show a significant drop at 20:30 UT, consistent with a peak in the scintillation parameter (Jin & Oksavik, 2018). However, a patch does not have to be exactly above the receiver to cause scintillations, because GPS satellites are seen in different directions and elevations, and so the patch can be observed at a different time.…”

“…Scintillations are associated with irregularities in electron density, which are found in events like storm-enhanced density, auroral precipitation, and polar cap patches (Alfonsi et al, 2011;De Franceschi et al, 2008;Jin et al, 2014Jin et al, , 2015Jin et al, , 2016Mitchell et al, 2005;Moen et al, 2013;Prikryl et al, 2010Prikryl et al, , 2015Spogli et al, 2009). Scintillations degrade position accuracy and can cause loss of lock (Aarons, 1982;Garner et al, 2011;Jacobsen & Andalsvik, 2016;Jin & Oksavik, 2018).…”