Patent ID: 8374785

Claim:
An improved vehicle location system, comprising: a GPS receiver carried aboard a vehicle and subject to interruptions of signal transmissions from orbiting navigation satellites; a DR-computer coupled to the GPS receiver and providing for range and heading information computed by dead-reckoning during periods of said signal interruptions, and such that vehicle location solutions are provided to a user; wheel-tick sensors coupled to the DR-computer and providing for rotational data related to the rotation of individual wheels that carry said vehicle; wherein, one or more parameters estimated to account for true radii of said individual wheels are combined with said rotational data from the wheel-tick sensors to generate delta-range information indicative of change in range, and delta-heading information indicative of change in heading, related to movements of said vehicle; wherein, said delta-range and delta-heading information are propagated by the DR-computer from absolute position information periodically obtained from the GPS receiver, with dead-reckoning location alone sometimes being output as a vehicle location solution; and wherein, said vehicle location solutions are derived solely from the GPS receiver, solely by the DR-computer, or from a mix provided by the GPS receiver and the DR-computer.