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Mobile navigation system

  • US 8,200,426 B2
  • Filed: 08/22/2001
  • Issued: 06/12/2012
  • Est. Priority Date: 01/06/1999
  • Status: Expired due to Term
First Claim
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1. A method for determining a current time zone for a mobile navigation system having a GPS receiver, the method comprising:

  • storing a digital representation of three sets of time zone division lines, ranging in accuracy from course to medium to fine, each of said three sets being represented by a number of polygons, wherein said number of polygons in each of said three sets is different in complexity from course to medium to fine;

    obtaining a position from the GPS; and

    comparing said position with said three sets of time zone division lines successively from course to medium to fine to determine how many of said three sets of time zone division lines said position is falling onto, wherein the current time zone is determined from a finer one of said three sets of time zone division lines that said position is falling onto.

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