Diploma in Physics in 1979, ETH Zurich, PhD thesis in gravity field determination in 1991. Presently he is professor in satellite geodesy and precise navigation at the geodesy and geodynamics lab. He works on precise Kinematic GPS, airborne Laser technique and GPS based landing approaches, geodynamic interpretation of GPS measurements, and 4-dimensional modelling of atmospheric refractivity. He is a fellow of the International Association of Geodesy and serves as president of the Swiss Geodetic Commission of the Swiss Academy of Sciences.