Options for the Iris satellite-based datalink

Iris is the European Space Agency's programme of satellite communications for Air Traffic Management (ATM). Iris aims at designing, developing and validating a new system for air-ground safety communications within the framework of the Single European Sky ATM Research (SESAR) Programme, to enable operational use by 2020. The system design studies are progressing in an iterative process with projects of SESAR Joint Undertaking. Overall, the general source of requirements for applications and communication performance is the FAA/Eurocontrol COCR v2 document, but several system-level requirements are not defined yet. User requirements are being defined by SESAR JU but some of them require a better understanding of their impact on the system design before a consolidation can take place. To this end, ESA studies have been analyzing the range of options for user requirements defined by aviation, and deduced the requirements for the user terminals, the characteristics required of the communication protocols, the link budget and, consequently, determined the requirements for the space segment and the ground segment. To cope with the uncertainties linked to the future operational concept and implementation of it, variation and combination of the user requirements is considered for defining “requirements options” that are further assessed and traded-off. The present Paper provides the latest results of the analysis of these requirements options, focusing on their consequences on the system design.