The Combined Surveillance Committee (CSC) has been actively developing updates to the Mode S Transponder and 1090 MHz Extended Squitter Automatic Dependent Surveillance – Broadcast (ADS-B) and Traffic Information Services – Broadcast (TIS-B) MOPS documents over the last several years. The CSC met for the first time in February 2016 and has been actively meeting and working towards delivering updated MOPS to RTCA in time for the RTCA PMC meeting in September 2020. The final meeting of the CSC is scheduled for June 2020 at EASA Headquarters in Cologne, Germany.

The CSC is a composite of four separate entities that includes SC-186 ADS-B Working Group (WG) 3, SC-209 ATCRBS/Mode S Transponder and EUROCAE WG 49 Mode S Transponders and WG 51 ADS-B. The harmonization of the Mode S Transponder and 1090 MHz Extended Squitter (1090ES) MOPS changes between RTCA and EUROCAE is of paramount importance to the international aviation community. Ultimately, the changes that result from the work of the CSC will be reflected in international standards at ICAO. One significant benefit that will result from the updates to the Mode S Transponder MOPS is cost savings potentially realized by eliminating legacy functions no longer utilized. The CSC is coordinating with other RTCA committees to incorporate required capabilities. The Committee is working with SC-206, Aeronautical Information and Meteorological Data Link Services to support broadcast of meteorological data via ADS-B and SC-147 Traffic Alert & Collision Avoidance System to support ACAS X and future collision avoidance coordination capabilities. One of the important drivers in updating the 1090ES MOPs is to support the Advanced Interval Management application in development by SC-186 WG4. The update to the 1090ES MOPS will provide support for reporting of supersonic and commercial space vehicles as well as the introduction of the capability to overlay phase-modulated data over existing 1090ES signals. This capability is being introduced as optional in this version of the MOPS but is expected to be the means of providing future capacity over the crowded 1090 MHz frequency as it is designed to increase capacity without adding additional signals or impacting congestion.