A comprehensive evaluation of the errors inherent in the use of a two‐dimensional shell for modeling the ionosphere

Abstract

Accurately modeling the ionosphere is a critical component to many radionavigation applications. However, in a significant number of cases, these models assume the ionosphere is compacted into a thin shell surrounding the Earth, rather than a full three‐dimensional field. While such models allow for ease of use and small storage needs, they are necessarily lacking in detailed information on the actual three‐dimensional distribution of electrons in the ionosphere. This paper attempts to quantify all geometric and numerical errors made through the use of a shell model. Such errors can reach as high as 14% on days of no strong ionosphere activity. Ultimately, this paper concludes that the highest levels of accuracy require the total electron content of the ionosphere be modeled three‐dimensionally. However, for those who must continue to use a shell model, a new mapping function has been derived which removes as much as 50% of the total errors seen using the previous, standard mapping function for shell models.