After a successful test, the FAA makes an enhancement to the Global Positioning System (GPS) called Wide Area Augmentation System (WAAS) available to some aviation users. WAAS improves the accuracy of GPS data by correcting some known measuring errors. “The system demonstrated one to two meters horizontal accuracy and two to three meters vertical accuracy throughout the contiguous United States,” says the FAA. The system will be operated by Raytheon. [Federal Aviation Administration, 8/24/2000] The deployment of WAAS is only one of many technological advances that could lead to pilotless aircraft navigation, including takeoff and landing. Tests have shown that landing by autopilot is possible (see also August 25, 2001). [Spinoff, 1998; Federal Aviation Administration, 8/13/1999; Rockwell Collins, 10/5/1999] WAAS also has non-aviation uses. It will be used during the rescue effort at Ground Zero. “[A]t the World Trade Center, rescue teams used WAAS to survey the site during the recovery program,” according to Avionics Magazine. [Avionics Magazine, 2/1/2002] After 9/11 there will be some speculation that the hijackers used GPS to navigate to their targets (see (September 12-17, 2001)). Some press reports will claim that 9/11 hijacker Mohamed Atta was at the WTC the day before the attacks to gather GPS data (see September 10, 2001).