This paper describes an advanced air traffic control surveillance and data system concept. The system is based on the use of satellites in 24-hour inclined, elliptical orbits for both communication and aircraft position determination and communications. Emphasis in the selection of this system was placed on the minimization of user aircraft equipment costs and the centralization of information processing. The future air traffic control problem is discussed, a description of the concept is given, and system performance is analyzed in detail. Models of significance error sources are described. An illustrative satellite design is given as well as cost estimates for the satellites and user equipment.