Unambiguous and continuous identification of aircraft: the use of Secondary Surveillance Radar (SSR) Mode S Elementary Surveillance moves up a gear

A significant number of flights landing at, and departing from, major airports and aerodromes in mainland Europe will now be identified by the aircraft’s own automatically downlinked aircraft identification and will no longer require a discrete SSR transponder code, but a common Mode S conspicuity transponder code (A1000). 

SSR transponder codes are a finite source (there are only 4,096 of them) and over the years it has become increasingly difficult to ensure that a sufficient number of codes is available during traffic periods in some areas of Europe. 

Downlinked aircraft identification is a feature of modern surveillance techniques, namely Mode S Elementary Surveillance, ADS-B and Wide Area Multilateration (WAM).   

The downlinked aircraft identification feature has been hailed as the most effective long-term solution to meet the objective of guaranteeing unambiguous and continuous identification of individual aircraft in European airspace. By early 2020, it will be ATC’s primary means of identifying the vast majority of aircraft flying under Instrument Flight Rules (IFR) as General Air Traffic (GAT). 

The ACID Programme coordinates the harmonised operational deployment of Mode S Elementary Surveillance, CCAMS (Centralised SSR Code Assignment and Management System) and enhanced functionality for ORCAM (Originating Region SSR Code Assignment Method), making for a seamless air traffic environment across Europe and ensuring that transponder codes are utilised as efficiently and effectively as possible. 

“The Network Manager, as part of its responsibility for SSR code management in Europe, will further integrate and harmonise the use of these three technological solutions aimed at improving ATM performance and achieving the SES objectives,” observed Joe Sultana, Chief Operations Officer at DNM.

Source: EUROCONTROL