Abstract: A sensor system for providing a cartographic overlay on a displayed sensor image for a current location within a selected region. The sensor system includes a sensor for generating the sensor image and a location device for generating a location signal corresponding to the current location of the sensor. Additionally, the system includes a storage device in electrical communication with the location device wherein the storage device electronically stores cartographic data for the selected region. The cartographic data consist of titles and symbols for known objects in the region. The storage device is operative to generate a map data signal corresponding to the cartographic data based on the location signal. The system further includes a display in electrical communication with the sensor and the storage device for presenting a final image. The display produces a final image that consists of the sensor image superimposed with cartographic data based upon the map data signal.

Abstract: A directional finding system for providing a corrected compass bearing based upon true north rather than magnetic north for a selected location. The true bearing is calculated by determining a present position with a GPS receiver or other location finding device, then selecting the deviation between true north and magnetic north for the present position from a store of magnetic deviation data, and finally correcting the magnetic bearing by the deviation to find a true bearing. The store of magnetic deviation data comprises the deviation between true north and magnetic north for any location. Additionally, the true bearing can be further corrected by a time-based magnetic deviation based upon the monotonic movement of the magnetic north pole. The true bearing is presented on a display along with the magnetic bearing and the present position.

Abstract: A method for forming a two-dimensional map of a three-dimensional object has the steps of mapping the three-dimensional object to an ellipsoid and then mapping the ellipsoid to a two-dimensional surface. Mapping of the three-dimensional object to the ellipsoid is accomplished by forming a plurality of generally parallel, generally planar slices of the three-dimensional objects which correspond to similar slices of the ellipsoid and projecting each point on the surface of a slice of the three-dimensional object to a corresponding point of the ellipsoid. Mapping the ellipsoid to two-dimensional surface may be done according to various different contemporary methodologies.