Process for reducing code change searches in a global positioning system receiver and system for aligning the time base of a mobile station

摘要

"PROCESS OF REDUCING SEARCHES FOR CODE CHANGE IN A GLOBAL POSITIONING SYSTEM RECEIVER AND SYSTEM FOR ALIGNING THE TIME BASE OF A MOBILE STATION". A process and system improves signal acquisition at a Global Positioning System (GPS) receiver by providing information to focus the acquisition search on the receiver. In particular, the invention relates to the case in which a GPS receiver is integrated with a transceiver that is capable of communicating with a cellular or GPS network via the particular aerial interface of that network. The standard information provided by the network is used to assist the integrated GPS receiver and improve its sensitivity and latency. The result of this improvement is that the receiver can quickly acquire satellites and compute its position in environments where conventional isolated GPS receivers cannot. This added performance is very important for the emergency location application, since the user can have high expectations regarding personal safety in various situations. In addition, rapid acquisition reduces energy consumption, which is very important for battery powered devices using such combined GPS and cellular technologies.