Observations of Equatorial Scintillation Using GPS Receivers

Jonathan Nichols, Andrew Hansen, Todd Walter, Per Enge

Abstract:	The National Satellite Test Bed (NSTB) is currently preparing for the upcoming solar maximum by installing GPS receivers in regions of high ionospheric activity. These receivers are intended to monitor ionospheric activity levels and to estimate their expected performance under conditions of high ionospheric stress. Two receivers have been installed in Santiago, Chile, which is located near the geomagnetic equator in the equatorial anomaly region. These receivers include a survey grade dual fi-equency semi-codeless receiver, which is being used in the NSTB’S South American prototype WAAS system, and a high bandwidth single frequency receiver specifically designed to estimate ionospheric scintillation levels in real time. Numerous scintillation events were observed by these receivers from the period of February 6ti through March 2nd. Most events occurred in the evening between sunset and midnight with a few events occurring in the early morning. These events were characterized predominately by moderate to high S4 levels, and low a$ levels. These observations are in marked contrast to measurements made in Fairbanks, AK during a magnetic storm in August 1998, where numerous phase scintillation events were recorded, but little to no amplitude activity was measured [9]. Coincident with the high scintillation levels, the dual frequency receiver reported numerous epochs where its own L1 ardor L2 pseudorange andior carrier phase measurements were not reliable. Nevertheless, for a vast majority of the time, the receiver was able to track through the events without requiring a reacquisition.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	1451 - 1460
Cite this article:	Nichols, Jonathan, Hansen, Andrew, Walter, Todd, Enge, Per, "Observations of Equatorial Scintillation Using GPS Receivers," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 1451-1460.
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