GNSS Data Processing Investigations for Characterizing Ionospheric Scintillation

M. Najmafshar, S. Skone and F. Ghafoori

Abstract:	Ionospheric scintillations are generally characterized via scintillation indices, calculated from amplitude and phase of the received GNSS signals. For many scintillation monitoring and mitigation applications, it is important to determine these indices accurately. Investigating appropriate data algorithms (here, data detrending) in deriving scintillation information for mitigation applications is the focus of this paper. Commonly, most GNSS receivers use a Butterworth filter with a fixed cutoff frequency of 0.1 Hz to remove low frequency trends from the data [Forte and Radicella 2002, Mushini, et al., 2012]. However, as shown in Forte and Radicella, 2002, inherent characteristics of ionospheric effects at different regions require different detrending settings. In this study, four detrending methods and effectiveness of each are examined using real data sets from high latitude and equatorial regions. Based on our results, it is observed that data detrending via wavelet-based filter can result in cleaner (less noisier) signal. In addition, correlation between computed amplitude and phase scintillation indices improves when wavelet filtering is used. Moreover, we present initial considerations for scintillation monitoring and mitigation via exploiting new GNSS signals to determine additional information. To examine real data, IF samples from scintillation events are post-processed using the GSNRx™ software receiver, developed by the Position, Location and Navigation (PLAN) group at the University of Calgary. This software receiver has the capability of processing GPS L1C/A and L2C signals. Scintillation parameters are calculated using the post-correlator in-phase (I) and quadra-phase (Q) components and carrier phase measurements, all obtained from the software receiver.
Published in:	Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014) September 8 - 12, 2014 Tampa Convention Center Tampa, Florida
Pages:	1190 - 1202
Cite this article:	Najmafshar, M., Skone, S., Ghafoori, F., "GNSS Data Processing Investigations for Characterizing Ionospheric Scintillation," Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014), Tampa, Florida, September 2014, pp. 1190-1202.
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