Hybrid positioning using synchronous and asynchronous techniques

Abstract

Methods and apparatuses for a mobile station to obtain a position fix using synchronous hybrid positioning and asynchronous hybrid positioning techniques are described. In one embodiment, a wireless communication apparatus may transmit a request to a mobile station for fine time assistance (FTA) corresponding to a global navigation satellite system (GNSS). The apparatus may be configured to receive the FTA, first timing measurements from one or more base stations, and second timing measurements from the GNSS. The apparatus may identify whether the FTA was received from the mobile station. If it is determined that the FTA was received, then a system frame number (SFN) received within the FTA may be identified, wherein the SFN is associated with one of the base stations. The apparatus may then establish a position fix for the mobile station using a synchronous hybrid positioning technique that involves relating the timing measurements to a time scale associated with the SFN. If it is determined that the FTA was not received, then the apparatus may establish the position fix using an asynchronous hybrid positioning technique.

What is claimed is: 
     
         1 . A method for a mobile station, comprising:
 forming one or more pseudoranges for the mobile station based on first timing measurements and second timing measurements, wherein:   the first timing measurements are obtained by the mobile station from at least one base station, and the second timing measurements are obtained by the mobile station from a global navigation satellite system (GNSS);   a time scale for the first timing measurements and a time scale for the second timing measurements are not interrelated; and   establishing a position fix for the mobile station based on the pseudoranges.