Terminal area surveillance system

The terminal area surveillance system (TASS) is a multifunction, ground-based radar system. It is being developed to replace the airport surveillance radars (ASR-7s, 8s and 9s), terminal Doppler weather radars (TDWRs), and low level wind advisory systems (LLWASs) in the 2004 to 2010 time frame. The terminal area surveillance functions that can be met by an e-scan system are depicted. The system is being procured under the Federal Aviation Administration´s implementation of Office of Management and Budget Circular A-109. TASS is entering Phase 2, the demonstration and validation phase, of that process. The TASS program is a complementary system to the Global Positioning Satellite (GPS) system being implemented by the FAA. The TASS does several important functions that cannot be accomplished by the space-based GPS system. These include: positive control of the 30 to 40 percent of general aviation aircraft that do not have electrical systems capable of supporting the GPS avionics; aircraft intrusion detection; bird detection; and wake vortex, thunderstorm and gust front, microburst and wind field prediction and detection. It will also provide positive control for special operational aircraft such as medical evacuation and oil line inspection helicopters, and high performance military aircraft that may be operating inside the terminal area without transponders