A new approach for the planning of GPS campaigns, either static or kinematic, has been developed for the automatic determination of occlusions to the GPS signal due to natural or artifact obstacles. For each pixel of a raster map the maximum elevation of the obstacles depicted by a Digital Terrain Model is obtained in a polar diagram of the sky obstructions for each pixel of the map. Coupling this information with the satellite positions, given by the almanac file, it is possible to build satellites’ visibility maps. This is fundamental for areas where obstructions are determinant for the satellite-receiver inter visibility, such as mountain areas or city centers. The software is already suited for the integration within a GIS. The main reason behind this work is the need of planning the airborne surveys for environmental and meteorological studies organized by the Civil and Environmental Engineering Department of the University of Trento. It is possible to create maps of satellites’ visibility for the whole area (static survey) or for a trajectory (kinematic survey), either on the DTM surface (ground vehicles) or fully three-dimensional (airborne vehicles).