Patent ID: 7835863

Claim:
A vehicle navigation device includes a computer platform comprising: a global positioning system (GPS) receiver operable to acquire and track a GPS signal; a processor assembly; and a memory, wherein the memory includes: last recorded GPS information comprising at least one of Ephemeris information and Almanac information; a GPS velocity vector determination module operable to output a velocity vector in the absence of current Ephemeris based upon the tracked GPS signal and the last recorded GPS information; and a dead reckoning module operable to determine a current location of the navigation device based on the determined velocity vector and a dead reckoning startup location, comprising: a verification logic for determining an estimated position calculated from pseudo-ranges and Doppler values using the last recorded GPS information, then comparing the estimated position against a last recorded location, and using the last recorded location as the dead reckoning position if a difference between the estimated position and the last recorded location does not exceed a predetermined value.