Water vapor tomography using GPS phase observations: simulation results

Global positioning system (GPS) tropospheric tomography normally requires that the slant wet delays between the GPS satellites and the ground receivers are estimated with high accuracy, which may be difficult given the presence of a number of error sources. This paper presents an alternative approach, namely to estimate the three-dimensional structure of the atmospheric water vapor directly from raw GPS phase observations. The method is tested in a number of simulations, where the impact of network size, the possible horizontal and vertical resolutions, the observation noise, and the inclusion of additional global navigation satellite systems were studied. The simulation results indicate that the refractivity field can be obtained with an accuracy of ~20% or better up to around 4 km with a height resolution of 1 km provided that a sufficient number of receivers and satellites is available