Scintillation Modeling for GPS/WAAS Receivers

Christopher Hegarty, M. Bakry El-Arini, Taehwan Kim, Swen Ericson

Abstract:	A scintillation signal model and a GPSAVAAS receiver model are developed. The scintillation signal model is based on a Nakagami-m distribution for intensity and a Gaussian distribution with zero mean for phase. The GPWWAAS receiver model includes L1 GPS and WAAS carrier and C/A code tracking loops, as well as semi-codeless L2 carrier and Y-code tracking capabilities. The results show that noncoherent DLLs typically used for code tracking are very robust to both amplitude and phase scintillations. Carrier phase tracking loops are much more susceptible to scintillation and the signal-to-noise threshold for reliable carrier tracking is very dependent on the scintillation strength. Fortunately, it appears that the worst-case scintillation encountered at mid-latitudes, including the U. S., will not significantly impact L1 carrier tracking performance. Semicodeless tracking of the L2 carrier is shown to be very fragile. Even weak scintillation can cause loss-of-L2 carrier lock for low-elevation satellites.
Published in:	Proceedings of the 1999 National Technical Meeting of The Institute of Navigation January 25 - 27, 1999 Catamaran Resort Hotel San Diego, CA
Pages:	799 - 807
Cite this article:	Hegarty, Christopher, El-Arini, M. Bakry, Kim, Taehwan, Ericson, Swen, "Scintillation Modeling for GPS/WAAS Receivers," Proceedings of the 1999 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1999, pp. 799-807.
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