…Here’s How It Works


The system uses a combination of radio signals and radar to give tower controllers a comprehensive view of what is on the field and where it’s going. This “multilateration” technology is a big step up from previous systems and is a “needed safety improvement,” according to the Department of Transportation’s Inspector General Ken Mead. Vehicles and aircraft are equipped with radio transponders that report to sensors placed strategically around the field. Anything larger than a minivan that doesn’t have a transponder is picked up by radar. The system constantly gathers all the information from both systems and funnels it into a computer that creates a screen display for controllers, which shows them the accurate location of every moving object on the field. The system also learns from its mistakes by adapting to false returns from buildings and trees. The Dallas-Fort Worth and Louisville airports are buying the system up front and Seattle-Tacoma is thinking of doing the same. Of the 33 FAA deployments, 24 are new installations and nine are upgrades of older systems.