Correlation of flight track data with other data sources

1. A method of triangulating aircraft transponder signals using a number of radio receivers connected to a central station over communication links, said method comprising the steps of:

applying at least one logic rule at each radio receiver to incoming aircraft transponder signals to filter redundant transponder signals,

time-stamping filtered transponder signals, and

transmitting time-stamped transponder signals to the central station.

2. The method of claim 1 , wherein the logic rules include at least one of altitude filtering, Mode S, Mode A/C code filtering, and change filtering.

3. The method of claim 1 , wherein replies are accepted when a change in state is indicated, such that the only those replies indicating a change in state are time-stamped and sent to the central server.

4. A system for triangulating aircraft transponder signals comprising:

a central station for receiving time-stamped signals from a plurality of radio receivers;

a plurality of radio receivers connected to the central station over communication links, each of said radio receivers comprising:

means for applying at least one logic rule at each receiver to incoming aircraft

transponder signals to filter redundant aircraft transponder signals,

means for time-stamping filtered aircraft transponder signals, and

means for transmitting time-stamped aircraft transponder signals to the central station.

5. The system of claim 4 , wherein the logic rules include at least one of altitude filtering, Mode S, Mode A/C code filtering, and change filtering.

6. The system of claim 4 , wherein replies are accepted when a change in state is indicated, such that the only those replies indicating a change in state are time-stamped and sent to the central server.