Abstract: An electronic compass for vehicles comprising at least two magnetic sensors arranged in use to be respectively responsive to orthogonal horizontal components of a magnetic field which includes the earth's magnetic field and a spurious magnetic field which is associated with the vehicle, for producing electrical signals corresponding to said components, data storage means arranged to store signals derived from the sensors as the vehicle is rotated in the horizontal plane during a compass setting cycle, and signal processor means responsive to electrical signals produced by the sensors after the setting cycle has been completed and to the signals stored during the setting cycle, for providing output signals indicative of the bearing appertaining to the heading of the vehicle in which the effects of the spurious magnetic field are compensated for.

Abstract: An electronic compass for vehicles comprising three magnetic sensors arranged in use to be respectively responsive to orthogonal components of a magnetic field which includes the earth's magnetic field and a spurious magnetic field which is associated with the vehicle, for producing electrical signals corresponding to said components, tilt sensor means responsive to vehicle tilt with respect to the horizontal plane, data processor and storage means arranged to store signals derived from the sensors as the vehicle is turned through a compass setting cycle, and signal processor means responsive to electrical signals produced by the sensors after the setting cycle has been completed and to the signals stored during the setting cycle, for providing compensated signals related to the bearing appertaining to the heading of the vehicle in which the effects of the spurious magnetic field are compensated for and further processor means to which the compensated signals are applied and which is responsive to the tilt se