Vehicle navigation system provided with an adaptive inertial navigation

Abstract

A navigation system for a road vehicle comprises a route-determining unit and position-locating means. The route-determining unit works together with a mass memory which stores geographic data of a road network. The route-determining unit determines a driving route between a starting point and a destination supplied by the driver of the vehicle. The position-locating devices determine the vehicle position coordinates recurrently from the speed and acceleration of the moving vehicle provided by a measuring unit. A correction unit derives a correction vector for correcting the generated vehicle position coordinates. The correction vector is determined by performing a transposition of the generated vehicle position coordinates to an actual road position as repeated by coordinates of the road network stored in the mass memory. An acceleration operator is derived from the measured speed and lateral acceleration and from the generated vehicle position coordinates. The acceleration operator operates on the correction vector in order to derive a correction value for the measured acceleration. A receiver receives position coordinate signal from a navigation satellite. A Kalman filter mixes the vehicle position coordinates with the position coordinates originating from the navigation satellite.