Abstract: Apparatus for air navigation to a point of known location which is separated from a VOR beacon of known location. The apparatus comprises storage means for storing signals representative of, respectively, the known locations of said point and said VOR, an estimated ground speed, an estimated range-to-go to said point, and an estimated course to said point, means for receiving from a VOR signal receiver/VOR bearing generator a signal representative of the current bearing of said VOR beacon, a bearing change generator for generating a signal that is representative of the change in the VOR bearing, a course estimator for generating a signal representative of an updated course heading, a range-to-point estimator for generating a signal representative of the range-to-point, and control means for controlling the bearing sampling and for activating the course estimator at predetermined intervals.