METHOD FOR MINIMIZING THE MAXIMUM SYSTEM TIME UNCERTAINTY FOR A MOBILE STATION

摘要

The maximum system time uncertainty for a mobile station in a wireless communications system using GPS signals for position determination is minimized by using aiding information from base stations, such as neighbor search window size (NSWS) parameters or neighboring pilot measurements (NPM). Knowledge of the last successful position determination fix (LSPDF) and the speed of the mobile station may also be used. In one embodiment, a weighted combination of estimates based on NSWS parameters, neighboring pilot measurements and/or last successful position determination fix is used. The search time window is then proportional to the maximum system time uncertainty plus position uncertainty.