ADS-B Full Deployment By 2013
ADS-B will be fully operational in the U.S. by 2013; the FAA announced Friday that it had approved full deployment of the satellite and ground-based system. In a statement, the agency said it approved full deployment after successful testing of full systems at Philadelphia, Louisville, over the Gulf of Mexico and in Alaska proved it could work in the full range of operating conditions. "This approach ensured that ADS-B was tested in the most extreme environments, allowing the agency to uncover and resolve any anomalies before the commissioning," the statement said.
The FAA has already installed 300 of the 800 systems that will be required to ensure ADS-B provides all the coverage that radar does now. In mountainous areas, a system of ground sensors called Wide Area Multilateration will provide coverage for the nooks and crannies that the ADS-B sensors can't see. WAM will also serve as a backup for GPS in high-traffic areas. By 2020, aircraft operating in controlled airspace will have to have ADS-B out capability to announce their position and identification. If they have the optional ADS-B in they'll get cockpit displays of traffic and weather.