GPS satellites  Barrow  Kotzebue  Bethel  Fairbanks  Iqaluit  Anchorage  Juneau  Cold Bay  Goose Bay  Winnipeg  Gander  Auburn  Billings  Olathe  Farmington  Nashua  Ronkonkoma  Freemont  Salt Lake  Aurora  Oberlin  Longmont  Leesburg  Palmdale  Memphis  Fort Worth  Hampton  Albuquerque  Houston  Jacksonville  Miami  San Jose Del Cabo  San Juan  Honolulu  GEO satellite  Puert Vallarta  Mexico City  Merida  Tapachula  Legend  GEO satellite  Wide-area reference station (WRS)  New WRSs  Wide-area master station (WMS)  Ground uplink station  Figure 5-9. Wide Area Augmentation System (WAAS).  more safety benefits such as improved situational  awareness (SA), near real-time weather information,  and additional voice communications.  2. ADS-B services have been deployed to all 24 modernized enroute ARTCCs and the largest terminal radar approach control facilities in the NAS.  In 2020, ADS-B will be mandatory for all aircraft in almost all NAS controlled airspace. [Figure 5-8] 3. Satellite-based technologies, including the Wide Area Augmentation System (WAAS), are improving access to runways at both large and small airports. [Figure 5-9] Directions and maps have been published  for more than 500 precision-like approaches enabled by WAAS. Localizer performance with vertical guidance (LPV) procedures improves access to airports in lower visibility conditions and where obstacles are present. These procedures are particularly valuable for smaller airports used by general aviation. There are now oer 2,300 LPV procedures available at runways where no instrument landing system (ILS) is present. 4. The Ground-Based Augmentation System (GBAS) has  been approved for Category I operations and the first satellite-based system has been approved for this category of precision approach which enables instrument-based operations down to 200 feet above the surface even during reduced visibility. [Figure 5-10] GBAS was installed at Houston, Texas and Newark, New Jersey airport in 2009. 5. Multilateration, a ground-based surveillance technology, is being implemented to help improve runway access. The FAA installed and is now using wide area multilateration (WAM) systems to control air traffic in Juneau, Alaska, and at four airports in Colorado. This allows air traffic to be safely separated  by five miles whereas before each aircraft had to clear  the airspace around the airport before the next could  enter.  6. New runways at Chicago O’Hare, Washington Dulles, and Seattle-Tacoma Airports opened in November of 2008, which are now beginning to have a reduction in delays. 5-6