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Abstract

The Galileo Reference Troposphere Model of ESA defines the algorithms for the calculation of zenith tropospheric delay and the mapping functions, to be implemented in navigation receivers. The model describes the dependence of delay on position, season, elevation angle and surface meteorological data. A critical analysis has been carried out of the model and the procedures to extract vertical and slant delay values, in particular with respect to consistency and scientific soundness. The main results of this study are discussed. ZENITH DELAY Refractivity model The classical model for refractivity, formulated by Smith and Weintraub (7) is: with where ( ) dry vapour N N