A method and system in which a vehicle carries an on-board positioning system and has access to a database of information pertaining to a plurality of fixed paths. A vector between the position of the fixed path and a position of the vehicle as reported by the positioning system is calculated prior to...http://www.google.de/patents/US7142982?utm_source=gb-gplus-sharePatent US7142982 - System and method for determining relative differential positioning system measurement solutions
