Patent ID: 8325087
Filing Date: 2012-12-04
Classification: G01S

Abstract:
1. A method for determining whether a wireless device has transmitted one or more forged satellite measurements, comprising the steps of: (a) determining an estimated location of the wireless device, the estimated location including a predetermined uncertainty area; (b) determining acquisition assistance data for a first set of satellites as a function of the estimated location by a location determining system, the assistance data including a code phase uncertainty window corresponding to said predetermined uncertainty area; (c) for ones of the first set of satellites from which the wireless device receives a signal, comparing code phase information measured by the device to code phase information in the determined acquisition assistance data; and (d) at the location determining system identifying one or more forged satellite measurements if a difference between said measured code phase information for said ones of the first set of satellites and said code phase information in the determined acquisition assistance data for the same ones of satellites is greater than a predetermined threshold, said predetermined threshold being defined by said code phase uncertainty window.