A system architecture approach for the Cherenkov telescope array (Conference Presentation)

Abstract

The Cherenkov Telescope Array (CTA) is planned as the first ground-based gamma-ray observatory open to the worldwide physics community. The CTA Observatory (CTAO) will consist of arrays of up to 100 telescopes at two sites, one in the Northern and one in the Southern hemisphere, as well as complex and distributed software systems for an efficient operation of the arrays and for the management and scientific exploitation of the CTA data. One of the challenges in the design of such a large installation is to ensure that all the systems that compose the CTAO have well-defined scope and identified interfaces, allowing it to work reliably as a seamless whole. In this contribution, we provide an overview on a methodology for a model-based architecture approach, tailored to the CTA needs, with the main goals to (i) capture the stakeholder interactions with the CTAO, (ii) capture the processes and activities that will be required to successfully operate the CTAO and meet stakeholder expectations, including science operations and maintenance, (iii) agree on a functional decomposition of the CTAO into (sub-)systems and an allocation of the functionality to the (sub-)systems to assign responsibilities and identify interfaces. To accomplish this, we have developed an architecture approach based on process-based system scoping and using a notation based on the SysML and UML formalisms. The different views of the architecture model are presented, each focusing on different aspects of the CTAO. These views contain, among others, stakeholders and project objectives, activity diagrams for describing the CTAO processes, the context and structure of the CTAO system and sub-systems, and their relationships. In this contribution, we will focus on the methodology with a few selected examples.