US 6,983,202 B2
Implementing geo-fencing on mobile devices
Douglas R. Sanqunetti, Cicero, Ind. (US)
Assigned to Electronic Data Systems Corporation, Plano, Tex. (US)
Filed on Apr. 12, 2004, as Appl. No. 10/822,490.
Application 10/822490 is a continuation of application No. 10/301994, filed on Nov. 22, 2002, granted, now 6,721,652.
Prior Publication US 2004/0193368 A1, Sep. 30, 2004
This patent is subject to a terminal disclaimer.
Int. Cl. G01C 21/30 (2006.01)
U.S. Cl. 701—207 20 Claims
OG exemplary drawing
 
1. A method for monitoring a mobile device, the method comprising:
defining a route within a coordinate system using a plurality of polygons, with each polygon defined by at least one set of coordinates;
rotating at least one of the polygons such that at least one edge of each rotated polygon is parallel with an axis of the coordinate system;
identifying a set of coordinates associated with a particular location of a monitored device;
comparing the set of coordinates for the monitored device with the plurality of polygons to determine a location of the monitored device with respect to the route by:
identifying that a current polygon within the coordinate system comprises one of the rotated polygons;
rotating the coordinates for the monitored device by a rotation angle used to rotate the current polygon; and
comparing the rotated coordinates for the monitored device with the current polygon.