Abstract: A land navigation system, e.g. for a vehicle, which compensates for deviations and drifts of the system sensors. The system has movement sensors, the signals of which are digitalized to make periodic computations of the estimated position of the vehicle. A memory stores the estimated route. A digital cartographic data base is read to extract and memorize the useful zone of the route to be displayed and the coordinates of a readjustment point. A central processing unit for management and computation is programmed to compute deviation measurement between the estimated position and the real position of the vehicle at each readjustment point, and to give compensation parameters that are memorized and used during the next readjustment operation, and so on.