The future of air traffic control is satellite technology, not radar, according to the Federal Aviation Administration’s plan for a next-generation air transportation system.

A satellite-based program, known as Automatic Dependent Surveillance-Broadcast (ADS-B), would allow more planes to fly at the same time and improve safety, FAA officials said.

Studies suggest that today’s aviation system will be strained beyond capacity when demand triples in the coming years.

ADS-B will enable more precise navigation, permitting planes to fly closer to one another without colliding. The innovative system will broadcast Global Positioning System data directly from planes to neighboring aircraft and air traffic controllers. Radar, on the other hand, passively scans the airspace to locate flying planes.

For the first time, pilots — not just controllers — will have access to display screens that show details about nearby planes.

Full implementation of ADS-B is expected to take as long as 20 years. Onboard equipment and the necessary ground-station infrastructure will be installed in increments, while existing radar provides backup.

Radar is an outdated technology, the FAA says. Moving to ADS-B will let the agency eventually decommission some of the current ground radars. According to an FAA report, radar is imperfect and sometimes has trouble distinguishing airplanes from flocks of birds or patches of rain.

Radar’s constraints require planes to be separated by at least five miles in today’s National Airspace System, according to experts at the Air Transport Association (ATA), the airline trade group that lobbied for ADS-B. The system’s precision will allow planes to fly more closely without sacrificing safety, permitting increased airspace capacity.

Radar installations require large ground structures to house and support the equipment, according to the FAA. But ADS-B ground stations are the size of portable mini-refrigerators, so the FAA would not need to lease land to situate them. In addition, because the ground stations will be easier to place, they will provide better coverage to remote areas.

Increased airport capacity is another advantage of ADS-B. More accurate tracking will give air traffic controllers the ability to better manage the traffic arriving at and departing from congested airports. More planes will be able to fly from airports than before.

Currently, the ADS-B program is conceptual. Last September, the FAA officially committed to establishing it as the heart of the next-generation air traffic control system. The FAA has conducted operational evaluations in Alaska and the Ohio Valley.

For fiscal 2007, the FAA reserved $80 million to begin initial implementation of ADS-B in the National Airspace System. The FAA plans to let vendors install the ADS-B equipment and then lease services from the vendors — similar to how the agency currently buys telecommunications services.