Precise and continuous tracking with multi-satellite systemsof aircraft andlow flying satellites, accurate airbornemeasurement of gravity and gravity gradients, and satellitegradiometry have fundamentally changed our view on the de-termination of the Earth's gravity field. The papers in thisvolume describe these techniques in detail. The ideas arepresentedas complementary, and are used to develop newtheoretical concepts of gravity field analysis. Computatio-nal models using these techniques are also discussed and aretested in simulations.The papers presented in this volume are the result of an IAGsymposium held during the XX General Assembly of the Inter-national Union of Geodesy and Geophysics in Vienna, Austria,August 11-24, 1991.
