Method for providing assistance data to a mobile station of a satellite positioning system

摘要

Satellites of a satellite positioning system broadcast within the navigation signals ephemeris data having a certain period of validity. At a mobile station, ephemeris data are required for position-fixing. In assisted satellite positioning systems, acquisition of navigation signals emitted by the satellites is facilitated as assistance data are provided to the mobile station. At a server station, a request for assistance data issued by said mobile station is received, and the server station transmits ephemeris data as part of the assistance data to the mobile station in response to its request. The ephemeris data transmitted to the mobile station comprise long-term ephemeris data derived from satellite orbit predictions. The long-term ephemeris data have a period of validity substantially increased with respect to the ephemeris data broadcast by the satellites.