APPLICATION OF GPS TO A RAILROAD NAVIGATION SYSTEM USING TWO SATELLITES AND A STORED DATABASE

摘要

A method for determining the location of a vehicle whosemovement is constrained to a route whose location is fixed andknown, such as a train. An initial estimate of location is madebased upon information contained in a route database based ondistance traveled from a reset point. The accuracy of theestimated vehicle location is improved through use of just twoglobal positioning satellites.