. "Communication, navigation and surveillance (CNS) are the main functions that form the infrastructure for air traffic management, and ensure that air traffic is safe and efficient."@en . . . "1057111329"^^ . . . "3924"^^ . . . . . . . . . . . . "Communication, navigation and surveillance (CNS) are the main functions that form the infrastructure for air traffic management, and ensure that air traffic is safe and efficient."@en . . . . . . . . "54891526"^^ . . "Communication, navigation and surveillance"@en . . .