The European Space Operations Centre (ESOC) in Darmstadt, Germany operates spacecraft on behalf of the European Space Agency (ESA) and maintains the ground facilities and expertise for ESA and other institutional and commercial customers. ESOC is composed of two departments: the Mission Operations Department and the Ground Systems Engineering Department, of which the Navigation Support Office is an integral part. The main objectives of the Navigation Support Office (NSO)are the provision of expertise for high-accuracy navigation, satellite geodesy, and the generation of related products and services for all ESA missions and for third-party customers, as well as supporting the European GNSS Programmes: Galileo and EGNOS.