Patent ID: 7916072

Claim:
A method of providing assistance data to a mobile station for facilitating acquisition of signals emitted by satellites of a satellite positioning system, said satellites broadcasting within said signals, ephemeris data having a certain period of validity, said method comprising: receiving at a server station a request for assistance data from said mobile station; receiving at the server station said broadcast ephemeris data; deciding at the server station whether said mobile station could achieve a specified position fix accuracy if provided with said broadcast ephemeris data; and when it is decided that said mobile station could achieve a specified position fix accuracy: transmitting said broadcast ephemeris data to said mobile station; when it is decided that said mobile station could not achieve a specified position fix accuracy: transmitting long-term ephemeris data to said mobile station as part of said assistance data in response to said request, said long-term ephemeris data having a period of validity substantially increased with respect to said ephemeris data broadcast by said satellites and said long-term ephemeris data being derived from satellite orbit predictions.