Modeling ionosphere VTEC over japan based on GNSS regression models and geonet

Abstract

In [1-3], we have preliminary developed a method of estimating the local models of an ionosphere VTEC (Vertical Total Electron Content) based on Global Navigation Satellite System (GNSS) regression models (abbreviated by GR models) and have shown the ionospheric delay (or advance) in the sky over Japan using the Gps Earth Observation NETwork (GEONET) data provided from the Geographical Survey Institute (GSI) of Japan [4]. In this paper, we try to refine the local models based on the orthogonal polynomials for the VTEC at the ionospheric pierce points in the ionospheric single layer model by comparing with the Taylor series expansion. From the aspect of model fitting, we also discuss the best number of orthogonal polynomials for the local model of the VTEC from informational theoretical points of views such as AIC [5] and BIC [6]. © 2010 ISSN.