Patent ID: 8135537

Claim:
A method of generating data indicative of real time locations of a driver controlled self-propelled vehicle during its traversal of a route in an area having impaired reception of navigational signals emanating from satellites associated with a global positioning system comprising: progressively moving the vehicle along said route, said vehicle having a pair of wheels that are spaced apart and rotatable in ground contact about a common axis, generating signals indicative of predetermined incremental distance movements of each of said wheels, generating coordinate data during such progressive movement of the vehicle that are indicative of respective end point locations of route segments which are successively traversed by the vehicle during its movement along said route, generating data indicative of the length of each of said segments by a continuing measurement of the distance traveled by the vehicle during its traversal thereof and terminating the distance measurement upon the occurrence of a predetermined change in the heading of the vehicle during its traversal thereof, generating data indicative of the heading of the vehicle during the traversal of each of said segments, said heading indicative data being generated on the basis of a difference in incremental distance movements of said wheels during the traversal of the segment by the vehicle, and said coordinate data being generated on the basis of the length and heading indications for the segment associated therewith, and storing the generated coordinate data for subsequent evaluation of the driver's control of the vehicles movements along said route.