Patent ID: 6188959
Filing Date: 2001-02-13
Classification: G01C

Abstract:
Navigation device for dead reckoning, comprising:an input for receiving a distance signal from a sensor for determining a distance;an input for receiving a direction signal from a sensor for determining a direction;a processor for position calculation based on the distance signal and the direction signal received from the sensors;a memory device connected to said processor and having stored therein a digitized road map for comparison with a calculated position;a memory connected to said processor for storing a sequence of deviations between each of a series of calculated positions and a corresponding position on the digitized road map;said processor being programmed to correct a calculated position using a correction value derived on a basis of the stored sequence of deviations; andto save a sequence of deviations for deriving a correction value in the memory until a new deviation to be saved lies outside a defined limit.