Abstract: There is disclosed an area navigation system including signal averaging and lag compensation circuits to overcome VOR signal propagation instabilities and a meter sensitivity control circuit which decreases the sensitivity of a track angle deviation left-right needle display as the aircraft approaches a waypoint. Means are also provided for digitally displaying the aircraft bearing to the waypoint.

Abstract: There is disclosed a vertical guidance computer for general aviation aircraft operating in conjunction with an area navigation system to convert data representing the range from the aircraft to a runway or other target into a measure of the altitude at which the aircraft should be for a given descent rate. Means are provided for adding a correction representing the mean sea level altitude of the runway, and for pre-establishing an adjustable minimum descent altitude. When the range corresponding to the minimum descent altitude is reached, an appropriate warning is given. The system utilizes a time analog of range data and a scaling of the basic system clock in accordance with the desired glide slope or descent rate. The scaling is such that the number of cycles of the scaled clock directly represents the command altitude in feed above mean sea level.