The availability of an aeronautical mobile satellite service and the e
mergence of a global navigation satellite system should enable CNS ser
vices to be established for civil aviation, virtually worldwide. This
paper discusses how the development of a low-cost ADS system, employin
g these satellite services, might be used to the advantage of European
air traffic management (ATM). it indicates that the earlier action is
taken, the greater will be the potential benefits. This paper is an u
pdated version of that presented at the NAV(94) Conference in November
1994.