A method and apparatus for determining a location of a remote receiver is described. The remote receiver receives satellite tracking data from a server, which it stores in memory. This satellite tracking data has a predetermined validity time period associated with it. When a connection cannot be established between the remote receiver and the server and the predetermine validity time period of the satellite tracking data has expired, the remote receiver calculates acquisition assistance data using the expired satellite tracking data for use with obtaining ephemeris data from a satellite. The remote receiver then calculates its position using the receiver ephemeris data.