Effects of Automatic Dependent Surveillance (ADS) on DOD Flight Operations Over the High Seas

Domestic air traffic control (ATC) within the United States is based on the use of radar surveillance and very high frequency (VHF) communications, both of which are line-of-sight systems. Oceanic ATC, however, usually begins where these systems no longer provide service. There are no direct communications between aircraft and the oceanic centers once an aircraft is beyond line-of-sight range of VHF. Position reports at mandatory points along the route, filed verbally with Aeronautical Radio, Inc. (ARINC) by the pilot using high frequency (HF) radio, provide the only means for tracking oceanic flights. To assure safety in the oceanic environment, large separations must be maintained, forcing aircraft to operate on less than optimal routes. The tremendous increase in air traffic that has occurred during the 1980’s is expected to continue through the year 2000. Traffic on the North Atlantic Routes is expected to increase by 36 percent and on Pacific routes by 86 percent. This will require improved surveillance and communications systems if capacity is to be increased while maintaining present levels of safety. The United States Federal Aviation Administration (FAA) and the International Civil Aviation Organization (ICAO) and its special committee on Future Air Navigation Systems (FANS) have recognized the need for a more efficient ATC system and have developed a satellite based communications, navigation, and surveillance (CNS) concept. This concept of Automatic Dependent Surveillance (ADS), based on satellite communications technology, will revolutionize the way ATC is presently performed in large oceanic areas which are beyond the coverage of land-based radar and communications. The implementation of ADS, coupled with Global Navigation Satellite Systems (GNSS), ICAO's generic term which includes the U.S. Global Positioning System (GPS) and the Russian Global Orbiting Navigation Satellite System (GLONASS) is expected to improve safety, capacity, and efficiency of the oceanic ATC system. The objective of this paper is to focus on the existing environment of military oceanic flight profiles, describe and discuss the present and future North Atlantic environment of airspace and ATC, discuss teh ADS concept, and identify issues and possible impacts on DoD operations from ADS implementation. This paper will focus on the North Atlantic environment but the points presented are applicable on a global basis.