Abstract: A direction finder includes a terrestrial magnetism sensor, a magnetization correction means for correcting an output of the sensor with a magnetic field component produced by a vehicle itself on which the sensor is mounted and a correction amending means for amending a corrected output on the basis of coordinates of a cross point of a line extending perpendicularly from a coordinates corresponding to a correction amount produced by the magnetization correction means onto a perpendicular bisector of a line segment connecting two coordinates points obtained by the sensor at different time instances.

Abstract: A position determining apparatus for a vehicle in which movement components in longitudinal (southerly-northerly) and latitudinal (easterly-westerly) directions in a unit running distance of the vehicle are determined from an initialized location. The apparatus determines the longitudinal distance of the current position of the vehicle from the initialized location by integrating the movement component in the longitudinal direction and utilizes the longitudinal distance for determining a latitude difference from a reference latitude and a virtual latitude. The apparatus converts the movement component in the latitudinal direction at the virtual latitude into a latitudinal movement component at the reference latitude to determine the latitudinal distance of the current position of the vehicle from the initialized location. The latitudinal and longitudinal distances of the current position of the vehicle are displayed.