ADS-B has been deployed in many facilities with a great amount of transparency to the controllers by adding the data into existing radar mosaics. ADS- B ground stations are already mostly installed well ahead of the 2020 mandate. The 2020 ADS-B mandate requires all aircraft operating in Class A,B,and C airspace and any altitude above 10,000 except class G to have ADS-B OUT capabilities.
ADS-B has two modes, IN and OUT. OUT is the broadcast from the A/C including ID, Position and altitude. This is the mode that will be required by the 2020 mandate. ADS-B IN is information being sent to the A/C which would include TIS-B and FIS-B. TIS-B (Traffic Information Service) provides position reports on Non ADS-B aircraft secondary radar returns, Similar to TCAS. FIS-B (Flight Information Service) provides terrain information, Weather and other products.
In Seattle Center airspace ADS-B can cover all of the airspace at 3000AGL. This may be further improved if Space Based ADS-B is adopted by the FAA. A constellation of 60 satellites will be launched beginning this year by Aireon Corp, to provide a top down receiver network for ADS-B to supplement the ground based systems. This system has a larger latency than the ground based system but would provide world wide surveillance for Oceanic Operations, and to a lesser degree greater mountainous terrain tracking.