The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 22, 2009
Filed:
Oct. 21, 1998
Peter James Duffett-smith, Cambridge, GB;
Paul Hansen, Cambridgeshire, GB;
Peter James Duffett-Smith, Cambridge, GB;
Paul Hansen, Cambridgeshire, GB;
Cambridge Positioning Systems Ltd., Cambridge, GB;
Abstract
The invention relates to a determining the position of a mobile receiverin a digital telephone network positioning system. A first receiveris at a known location and others are mobile. The method involves transmitting signals from a plurality of sourcesthe transmission signals having a format at least a portion of which has predetermined values or a portion of which is repeated. The time offset of the transmission signals received at each receiverfrom a transmission sourcerelative to a reference clock of each receiver is determined by generating a reference signal locked to the reference clock. The reference signal has a similar format to the transmission signals and includes a portion identical to the predetermined values or repeated portion of the received signal and compares the received transmission signal and the reference signal. The time delay between the respective signals received at the receiversis determined from their relative time offset, to thereby determine the position of the other receivers