Civil aviation's global necessity beyond GPS-based systems-IGSANS

Developments are in progress toward utilizing GPS for global ATC surveillance and landing guidance. However, although these GPS-based systems offer major advantages over existing systems, there are critical shortcomings including integrity, availability, continuity and security which cannot be practically solved with GPS/GNSS-based systems. Recognition of this fact is necessary now so that planning of evolutionary changes can be made toward a system meeting all the requirements at a minimum cost. It is believed that such a system, called the integrated global surveillance and navigation system (IGSANS), will meet the requirements. It would provide ATC surveillance, area navigation, collision warning/avoidance, Cat.I landing guidance and high speed data link functions globally, and precise Cat. II/III landing guidance through flare, touch-down and reallot where needed in terminal areas. It is a combined ground and satellite based system which would provide much needed system redundancy with substantial cost savings in both the airborne and ground/satellite facilities. IGSANS is briefly described, and its functional performance, economic and other advantages are discussed.