Radio navigation system for aircraft.

A tactical air navigation system, commonly referred to by the acronym TACAN, is a navigation system initially designed for naval aircraft to acquire moving landing platforms (i.e., ships) and later expanded for use by other military aircraft.

An air navigation service provider is a public or a private legal entity providing Air Navigation Services.glossary by Eurocontrol It manages air traffic on behalf of a company, region or country.

an avionics system which provides direct data link communication between the pilot and the air traffic controller.

The Plan for the Security Control of Air Traffic and Air Navigation Aids is an emergency preparedness plan of the United States which prescribes the joint action to be taken by appropriate elements of the Department of Defense, Federal Aviation Administration, and the Federal Communications Commission in the interest of national security in order to effectively control air traffic and air navigation aids under emergency conditions.