A tracking system that provides a ground control approach (GCA) air-traffic controller with a precise display of an aircraft's position relative to a runway final-approach course. To ensure absolute safety, precise information is displayed on a plan position indicator (PPI). This display provides the controller with aircraft position information for control of heading and rate of descent.

To accomplish this and maintain the required precision for a final-approach aid, the display shows the aircraft position in relation to range, azimuth, and elevation. The information presented on the precision approach radar display allows an air-traffic controller to direct a pilot down along a runway approach course to a precision landing. Precision radar approaches are accomplished in most weather conditions and do not require any on-board avionics equipment, such as an instrument landing system (ILS).