Ionospheric Scintillation Effects in the Equatorial and Auroral Regions

Patricia H. Doherty, Susan H. Delay, Cesar E. Valladares and John A. Klobuchar

Abstract:	Ionospheric scintillation effects on GPS signals and ultimately on satellite navigation and communication is a growing concern. This concern is primarily due to the challenges that intense scintillation may pose on these systems during periods of high solar activity. The most extreme scintillation activity is expected to occur in the equatorial anomaly regions during the evening hours at high solar activity levels. The auroral and polar cap regions are also expected to experience significant scintillation activity during geomagnetically disturbed periods. Scintillation is expected to be rare in the mid- latitudes, limited to periods of extreme geomagnetic activity. The FAA's National Satellite Test Bed (NSTB) has been monitoring scintillation activity at Fairbanks, Alaska since mid-1998, intermittently from Santiago, Chile since February 1999 and more recently from Mauna Loa, Hawaii. The Air Force Research Laboratory (AFRL) has also initiated long term scintillation measurements near the magnetic equator at Ancon, Peru and at several locations in the equatorial anomaly region. These measurements have been made with a commercially available Ionospheric Scintillation Monitor (ISM) developed by GPS Silicon Valley. The ISM is a modified NovAtel GPS single-frequency receiver that measures amplitude and phase scintillation parameters in real-time. In this paper, we submit a summary of the scintillation activity recorded by the NSTB at Fairbanks and by AFRL at Ancon. In addition, we correlate the scintillation activity with receiver performance of nearly co-located dual-frequency codeless L2 GPS receivers. The results of this study may begin to quantify the frequency and magnitude of scintillation at GPS frequencies at these two dynamic locations. It will also illuminate the effect that scintillation can have on the performance of co-located codeless L2 dual-frequency receivers and ultimately on GPS based satellite navigation for civilian receivers without access to the encrypted L2 code. Finally, it will serve as a test for the ISM receiver to monitor amplitude and phase scintillation in real-time.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	662 - 671
Cite this article:	Doherty, Patricia H., Delay, Susan H., Valladares, Cesar E., Klobuchar, John A., "Ionospheric Scintillation Effects in the Equatorial and Auroral Regions," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 662-671.
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