SYSTEM FOR SETTING COARSE GPS TIME IN A MOBILE STATION WITHIN AN ASYNCHRONOUS WIRELESS NETWORK

摘要

A method and apparatus for setting coarse GPS time in a GPS receiver in a mobile station (MS) that is communicating with a base station and a position determining entity (PDE). The MS requests an assistance message from the PDE that includes a sequence of predicted navigation bits, including a predicted time indicator field, which is then located and decoded. Coarse time is set responsive to the time indicator value. A Pattern Match Algorithm may be performed to provide more precise GPS time. In order to better set coarse time, an expected error in the Time of Week may be determined, by for example using the expected network latency. The system described herein enables the use of IS-801 protocol by an MS in asynchronous networks by improving the coarse time setting process.