The Decca Omnitrac Installation provides for the pilot a pictorial display on which the present position and track of an aircraft is continuously plotted. The system uses Dectra, Loran C, and Doppler for long range overwater flights, and Decca, VOR/DME and Doppler for short range flights. Automatic guidance through the autopilot along any selected flight path is included. The pictorial display provides a marked advance in reducing the cockpit workload by clearly showing the aircraft position on a chart, thus eliminating mental effort in estimating position. Safety is improved by clearly plotting the relationship of the aircraft to known geographical hazards. Accuracies in the order of a few miles have been observed on transatlantic flights. Accuracies are measured in yards under short range flight conditions.