Lincoln Laboratory 1030/1090 MHz Monitoring

Traffic Collision Avoidance System (TCAS) behavior in New England airspace is being monitored and analyzed, making use of an omni-directional 1030/1090 MHz receiver. The receiver system, located in Lexington, MA, operated by M.I.T. Lincoln Laboratory, is used to record data for subsequent analysis in non-real time. One aspect of the program focuses on communication taking place during TCAS Resolution Advisories (RA's). Omni-directional receptions make it possible to examine the air-to-air messages exchanged between aircraft for coordination of RA's. Omni-directional reception rates are also being studied. The results indicate the percentage of aircraft that are TCAS equipped and the percentage of received signals that originate from TCAS and other systems. A third aspect of the program evaluates the availability of 1090 MHz Extended Squitter data for use in collision avoidance systems. Data is recorded continuously, and the busiest periods are selected for focused attention.