Optimum detrending of raw GPS data for scintillation measurements at auroral latitudes

Forte, Biagio

doi:10.1016/j.jastp.2005.01.011

Cited by 72 publications

(97 citation statements)

References 22 publications

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“…However, the amplitude scintillation S 4 index remained low, a result that has been reported previously (e.g., Ngwira et al, 2010). Low S 4 index is sometimes attributed to imprecise detrending methods, which in turn may lead to overestimation of phase scintillation indices compared to amplitude scintillation indices resulting in phasewithout-amplitude scintillation (Forte and Radicella, 2002;Forte, 2005Forte, , 2007Mushini et al, 2010). Figure 3a and b shows TEC, the phase scintillation index σ φ and the ground magnetic field X-component in Taloyoak, where the magnetic local midnight and noon were at 06:37 and 19:04 UT, respectively.…”

Section: Instruments and Datamentioning

confidence: 51%

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

et al. 2011

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Abstract. Maps of GPS phase scintillation at high latitudes have been constructed after the first two years of operation of the Canadian High Arctic Ionospheric Network (CHAIN) during the 2008-2009 solar minimum. CHAIN consists of ten dual-frequency receivers, configured to measure amplitude and phase scintillation from L1 GPS signals and ionospheric total electron content (TEC) from L1 and L2 GPS signals. Those ionospheric data have been mapped as a function of magnetic local time and geomagnetic latitude assuming ionospheric pierce points (IPPs) at 350 km. The mean TEC depletions are identified with the statistical high-latitude and mid-latitude troughs. Phase scintillation occurs predominantly in the nightside auroral oval and the ionospheric footprint of the cusp. The strongest phase scintillation is associated with auroral arc brightening and substorms or with perturbed cusp ionosphere. Auroral phase scintillation tends to be intermittent, localized and of short duration, while the dayside scintillation observed for individual satellites can stay continuously above a given threshold for several minutes and such scintillation patches persist over a large area of the cusp/cleft region sampled by different satellites for several hours. The seasonal variation of the phase scintillation occurrence also differs between the nightside auroral oval and the cusp. The auroral phase scintillation shows an expected semiannual oscillation with equinoctial maxima known to be associated with aurorae, while the cusp scintillation is dominated by an annual cycle maximizing in autumn-winter. These differences point to different irregularity production mechanisms: energetic electron precipitation into dynamic auroral arcs versus cusp ionospheric convection dynamics. Observations suggest anisotropy of scintillationcausing irregularities with stronger L-shell alignment of irregularities in the cusp while a significant component of Correspondence to: P. Prikryl (paul.prikryl@crc.gc.ca) field-aligned irregularities is found in the nightside auroral oval. Scintillation-causing irregularities can coexist with small-scale field-aligned irregularities resulting in HF radar backscatter. The statistical cusp and auroral oval are characterized by the occurrence of HF radar ionospheric backscatter and mean ground magnetic perturbations due to ionospheric currents.

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Section: Instruments and Datamentioning

confidence: 51%

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

et al. 2011

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“…Also, it should be a constant, so that the scintillation values are comparable. For the case of GNSS scintillation data, a Butterworth filter with a constant cutoff frequency of 0.1 Hz is the most common approach, but it has been shown that this value is inappropriate at high latitudes [16,24].…”

Section: Cutoff Frequency Determinationmentioning

confidence: 99%

“…However, the estimated value of can be highly sensitive to the cutoff frequency of the filter. While the most common cutoff frequency is 0.1 Hz, it has been shown that this is suboptimal at high latitudes and that higher values like 0.3 Hz might yield better results [24]. The variation in the carrier phase of GNSS signals is also commonly quantified using the rate of total electron content index (ROTI) [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…The variation in the carrier phase of GNSS signals is also commonly quantified using the rate of total electron content index (ROTI) [25][26][27]. Several other indices for quantifying phase variations have also been proposed [24,[28][29][30][31][32]. It is worth noting that all of these indices are directly related to the scintillation signal variance.…”

Section: Introductionmentioning

confidence: 99%

“…A major advantage of wavelet filters is that they manage to preserve local features in the signal, thus avoiding misinterpretation that can occur when using standard filter approaches [24,[33][34][35][36]. While such wavelet filters may yield better results than conventional filters, the computational load can become very high, especially when processing data with high sampling rates (50+ Hz).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estimation of Scintillation Indices: A Novel Approach Based on Local Kernel Regression Methods

Ouassou

Kristiansen

Gjevestad

et al. 2016

International Journal of Navigation and Observation

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We present a comparative study of computational methods for estimation of ionospheric scintillation indices. First, we review the conventional approaches based on Fourier transformation and low-pass/high-pass frequency filtration. Next, we introduce a novel method based on nonparametric local regression with bias Corrected Akaike Information Criteria (AICC). All methods are then applied to data from the Norwegian Regional Ionospheric Scintillation Network (NRISN), which is shown to be dominated by phase scintillation and not amplitude scintillation. We find that all methods provide highly correlated results, demonstrating the validity of the new approach to this problem. All methods are shown to be very sensitive to filter characteristics and the averaging interval. Finally, we find that the new method is more robust to discontinuous phase observations than conventional methods.

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GPS scintillation and irregularities at the front of an ionization tongue in the nightside polar ionosphere

Meeren

Oksavik

Lorentzen³

et al. 2014

JGR Space Physics

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In this paper we study a tongue of ionization (TOI) on 31 October 2011 which stretched across the polar cap from the Canadian dayside sector to Svalbard in the nightside ionosphere. The TOI front arrived over Svalbard around 1930 UT. We have investigated GPS scintillation and irregularities in relation to this TOI front. This is the first study presenting such detailed multi‐instrument data of scintillation and irregularities in relation to a TOI front. Combining data from an all‐sky imager, the European Incoherent Scatter Svalbard Radar, the Super Dual Auroral Radar Network Hankasalmi radar, and three GPS scintillation and total electron content (TEC) monitors in Longyearbyen and Ny‐Ålesund, we observe bursts of phase scintillation and no amplitude scintillation in relation to the leading gradient of the TOI. Spectrograms of 50Hz phase measurements show highly localized and variable structuring of the TOI leading gradient, with no structuring or scintillation within the TOI or ahead of the TOI.

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Optimum detrending of raw GPS data for scintillation measurements at auroral latitudes

Cited by 72 publications

References 22 publications

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions

Estimation of Scintillation Indices: A Novel Approach Based on Local Kernel Regression Methods

GPS scintillation and irregularities at the front of an ionization tongue in the nightside polar ionosphere

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