DETERMINING POSITION WITHOUT USE OF BROADCAST EPHEMERIS INFORMATION

摘要

Devices and methods are described for determining position information without broadcast ephemeris data for extended time periods. A server or client device 110 receives or collects historical state data of satellites of a satellite-based positioning system and generates predictions of future satellite trajectories for future time periods. When a server generates the predictions, the predictions are subsequently transferred to a client device. The client device selects predictions appropriate to time of interest. The time can be any time during a period of at least seven calendar days. The client device reconstructs satellite states using information on the predictions and uses the reconstructed satellite states to acquire satellite signals as appropriate to the current location and time of the client device. The client device determines and/or tracks its position using information of the satellite states and timing information of the satellite signals.