| 摘要 |
A method and an appara-tus which acquire satellite posi-tioning system (SPS) signals in an SPS receiver. Information on time of day, approximate re-ceiver location, and satellite po-sitions are used to reduce the time to search and acquire sig-nals from one or more SPS satellites. In an example of a method of the invention, a first pseudorange to a first SPS satel-lite is determined, and an ap-proximate location of the SPS receiver is determined. An es-timated pseudorange for a sec-ond pseudorange to a second SPS satellite is determined from the approximate location and a satellite position of the second SPS satellite. The SPS receiver then searches for SPS signals from the second SPS satellite in a range determined by the esti-mated pseudorange. Typically, this method reduces the search time to initially acquire SPS signals from the second SPS satellite, and the estimated pseudorange is not based on a previously determined pseudorang e for said second SPS satellite. In a particular example of the invention, the approximate location is determined from a cell based information source which correlates an identification of each of various wireless cell sites with an approximate location for objects within a cell of a wireless cell based communication system, such as a cellular(or cell based) telephone system. In other examples of the invention , relatively precise time of day information may be used with information indicating satellite positions and information indicating the approximate location to determine an estimated pseudorange for a first SPS satellite to be acquired.
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