Applications are invited for PhD positions in the following thematic areas: GNSS surveying and geodesy (e.g., RTK, PPP and CORS networks), GNSS remote sensing (e.g., meteorology, reflectometry, ionospheric sounding) GNSS air/space-based applications (e.g., relative navigation, attitude determination, formation-flying) GNSS quality control (e.g., integrity theory, ambiguity resolution, validation)