GPS tomography using phase observations

We present a tomographic method for retrieving the 3D structure of the tropospheric water vapor using GPS phase observation from a network of GPS receivers. We investigate the accuracy of this method through simulations. In these simulation also the impact of increasing the number of stations and including other Global Navigation Satellite Systems (GNSS) are investigated. We show that the wet refractivity below 4 km in height can be retrieved with an accuracy of 10-20% when using 25 station and 1 km vertical resolution.