Map-based land vehicle navigation system with DGPS

Commercial automobile navigation systems currently employ a Global Positioning System (GPS) receiver coupled with a dead reckoning system and a map-matching algorithm. The dead reckoning system, which compensates for GPS inaccuracies and frequent GPS signal obstructions, employs an odometer, a directional sensor, and a backlight signal. The dead reckoning system along with a map-matching algorithm updates the position whenever the vehicle completes a sharp turn into a street whose position is distinguishable on the stored map. In this paper a positioning system is proposed, which employs only a DGPS or GPS receiver and a map-matching algorithm. The algorithm correlates the received power from different GPS satellite vehicles (SVs), leading to a specific signature, to a stored map with periodic time-varying estimates of SVs received powers. An experimental approach is presented to examine the feasibility of applying the proposed positioning system.