Evaluation of separation performance with ADS-B at the Philadelphia key site

The Federal Aviation Administration's (FAA) Surveillance and Broadcast Services (SBS) Program Office has implemented one of the first enablers of the Next Generation Air Transportation System (NextGen) by installing a ground infrastructure that supports the Automatic Dependent Surveillance-Broadcast (ADS-B) data service. One of the main applications for this infrastructure is to enhance air traffic control (ATC) separation through more frequent and accurate data about aircraft. As part of the initial assessment activities, the ADS-B data was incorporated into four different automation platforms in four different key sites. One of these key sites was the Philadelphia Terminal Radar Approach Control (PHL TRACON) which uses Standard Terminal Automation Replacement System (STARS) to process and display radar data to controllers. The Philadelphia STARS was updated to accept ADS-B data in its native format. Beyond just accepting new surveillance data, however, PHL TRACON is the first location that went operational where ATC used system track positions (so called- “fused” targets) published to the ATC display to allow controllers to separate aircraft, a paradigm shift from current operations where controllers use radar “plot” positions. As part of the SBS evaluation, a working group was created that worked specifically to evaluate the end-end performance of separation services with the new data flow - ADS-B avionics, ADS-B surveillance service on the ground, and the updated STARS software. The evaluation used a comparative approach with current monopulse secondary surveillance radar (MSSR) systems as a baseline; if the new system performed as good or better than MSSR systems in separation applications, then the system was acceptable for operation. This paper describes the efforts of the SBS working group to evaluate the operational performance in Philadelphia, including the metrics used, assumptions made operational scenario development, and results from several analyses, including simulation, flight testing, and targets of opportunity operating in the TRACON airspace.