The Selex ES SIR-S/I is a Mode S solution for the detection of cooperative targets in surveillance services. It has been designed to comply with the international standards for Secondary Surveillance Radar (SSR) systems and to guarantee a high degree of maintainability and reliability.


The Selex ES SIR-S/I Secondary Surveillance Radar is a modular system fully compliant with ICAO and EUROCONTROL recommendations on Mode S operation. It can be installed as standalone equipment or integrated (co-mounted) with a Primary Surveillance Radar (PSR).

The Selex ES SIR-S/I is a dual-channel system with automatic changeover, solid-state transmitter and receiver designed for unmanned operation. The dual channel system is housed in a single cabinet providing an integrated solution with embedded tracking function and embedded ADS-B channel.

The Selex ES SIR-S/I can operate in SSR Conventional Modes (1, 2, 3/A, C), Mode S Elementary and Enhanced Surveillance up to full Extended data link operation employing level 5 transponders. It is equipped with a dedicated ADS-B receiving channel and processing chain in order to acquire, decode and process 1090MHz Extended Squitter messages from Omni and Sum MSSR antenna channels. The SIR-S/I ADS-B receiving channel is designed according to ICAO Annex 10, RTCA DO-260, RTCA DO-260A, RTCA DO-260B specifications.

Mode S allows high data integrity (synchronous garbling elimination, defruiting), unambiguous aircraft identification, improved situation awareness and safety enhancements by the use of the additional information extracted from the transponder (Call-Sign, Selected Altitude, Ground Speed, Magnetic Heading, etc.).

The antenna used with the equipment is the ALE-9 LVA antenna, designed or full monopulse operation. It provides high directional properties in azimuth and high aperture in the vertical plane, as recommended by ICAO, in particular for Enhanced Mode S Surveillance (EHS) operation.

The Selex ES SIR-S/I Mode S operation has been fully tested and in the framework of the EUROCONTROL PreOperational Mode S Station Implementation Programme (POEMS). In addition, the system is compliant with all the SSR and Mode S performance requirements demonstrating outstanding performances in terms of accuracy figures and de-garbling, defruiting algorithm efficiency.