Magnetic Storm Modeling for the Wide Area Augmentation System (WAAS) Simulation Studies

Steven Chavin

Abstract:	As part of ISTI’s ionospheric modeling program to support the IV&V of the Federal Aviation Administration’s Wide Area Augmentation System (WAAS) algorithms we have created a set of magnetic storm models, as well as a set of models for the undisturbed ionosphere. The goal of the magnetic storm modeling program is to create realistic storm models, which will span the range of the ionospheric storminess parameters discussed in a previous ION conference paper. This paper discusses the procedure we have used to generate the storm models based to the greatest extent possible upon published observational data. The magnetic storms of Dec. 17, 1971, Oct. 21, 1989, Nov. 3, 1993 and other storms are used to provide scenarios. The WAAS system will provide the user with a grid of value of vertical ionospheric delays. The vertical ionospheric delays are a measure of the ionosphere’s vertical total electron content (TEC). During magnetic storms the TEC may change rapidly with time or have large spatial gradients. These conditions will make it difficult for the WAAS system to maintain accurate values of the delay at the grid points. Also during magnetic storms the vertical distribution of the electron density may create inaccuracies as the user translates the vertical delays into slant delays. Plots will be shown characterizing the three dimensional spatial and time variations of the electron density as well as the level of stress on the WAAS system using the ionospheric storminess parameters. Comparisons will be made with the ionospheric storminess parameters of the ionosphere during quiet periods.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	891 - 899
Cite this article:	Chavin, Steven, "Magnetic Storm Modeling for the Wide Area Augmentation System (WAAS) Simulation Studies," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 891-899.
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