At 11:25 PM 11/14/96 -0800, Lucky Green wrote:

If I remember correctly, some of the newer transponders used on commercial aircraft actually transmit GPS data back to the controller in real time. I wonder how long it will be before the FAA will include such information in their database.

I don't think new transponders make much difference. The old ones heighten the radar image of the airplane which gives an accurate 2D position. This position is automatically entered into the FAA computer which maintains the ATC controller's display. In the old style, altitude is determined by an altimeter on the airplane which encoded into the transponder signal. If newer transponders are returning GPS signals, the position may be more accurate (but probably not unless they can decode the selective availability signal). (OBCrypto for those who care.)

"To obtain the position of any passenger flight in the US within 10 meters, click here."

In either case, the Passenger Name Records for the flight are in the airlines databases (and have been there for many years), and the airplane's physical position is in the FAA's computer (and has been for many years). The ability to find the current position of an airplane, or a passenger remains dependent on the incentives and disincentives for database linking and application development. There are no insurmountable technical problems. The technical problems are those of getting old-technology software to do something new. ------------------------------------------------------------------------- Bill Frantz | The lottery is a tax on | Periwinkle -- Consulting (408)356-8506 | those who can't do math. | 16345 Englewood Ave. frantz@netcom.com | - Who 1st said this? | Los Gatos, CA 95032, USA