Ionospheric Scintillation Monitoring Using GPS Based Space Weather Monitor

G. Crowley, I. Azeem, A. Reynolds, J. Santana, O. de la Beaujardiere, P. Roddy, G. Wilson

Abstract:	Ionospheric weather includes gradients and irregularities that lead to communication and navigation outages with operational impacts. Mitigating these impacts through ionospheric specification and now-casting, is a goal now within reach. However, there is insufficient data to adequately specify the global ionosphere because previous instruments have had inadequate performance, were too expensive, and 70% of the earth is covered in water, making instrument deployment difficult. The new low-cost CASES (Connected Autonomous Space Environment Sensor) GPS-based space weather monitor represents a revolutionary advance in space-weather monitoring capability. CASES is a paperback-novel-sized software receiver with robust dual-frequency tracking performance, stand-alone capability, and complete software upgradability. The receiver tracks L1 and L2 civilian signals (specifically L1 C/A, L2 CL and L2 CM). The sensor measures and calculates TEC with a relative accuracy of a few 0.01 TECU at a cadence of up to 1 Hz (post-processing up to 100 Hz). It measures amplitude and phase at up to 100 Hz on both L1 and L2-C, for up to 14 satellites in view. It calculates the standard scintillation severity indicators S4, ?o, and sigma-phi, and a new index, the Scintillation Power Ratio (SPR), all at a cadence that is user defined. It is able to track through scintillation with {S4, s0, amplitude} combinations as severe as {0.8, 0.8 seconds, 43 dB-Hz (nominal)} (i.e., commensurate with vigorous post-sunset equatorial scintillation) with a mean time between cycle slips of 480 seconds and with a mean time between frequency-unlock greater than 1 hour. A CASES GPS receiver has operated continuously at Jicamarca Radio Observatory, Peru since November 2011. Here, we describe variations in the measured S4 scintillation which was generally elevated between 20 LT and 01 LT. Comparisons are shown between CASES scintillation data versus ionospheric irregularities measured by the TIDDBIT HF sounder and C/NOFS satellite.
Published in:	Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012) September 17 - 21, 2012 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	2029 - 2037
Cite this article:	Crowley, G., Azeem, I., Reynolds, A., Santana, J., la Beaujardiere, O. de, Roddy, P., Wilson, G., "Ionospheric Scintillation Monitoring Using GPS Based Space Weather Monitor," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 2029-2037.
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