Ray tracing in the troposphere for GPS satellite signals Part I

Abstract

In this paper. we propose a suitable algorithm to compute ray tracing in the troposphere for GPS (Global Positioning System) satellite signals. We use aerological data (pressure. temperature and relative humidity) for different altitudes. Which can be obtained by radiosondes. Because a ray path depends on aerological conditions in time and space. and is not vertical when it reaches the troposphere. we assume that the refractivity is an exponential function of altitude and its values are . distributed on spherical surfaces. Furthermore. we assume that the troposphere is static. spherically stratified and concentric with the Earth. As a result. we obtain that the optical path is greater than the geometric one. This fact must be considered to improve geodetic positioning.