Speaker
Ms
Elena Salazar
(GMV)
Description
Activity: TRP
ESA TO: Mr. Christophe Honvault - Software Systems Divisions
The ESA AAML (Avionics Architecture Modelling Language) study, led by GMV and with the participation of TAS-F, aimed at advancing the avionics engineering practices towards a model-based approach by identifying and prioritizing the analyses of interest to be performed based on an avionics architecture model, specifying the modelling language features necessary to support those analyses, and prototyping a software tool to demonstrate the automation of the analyses.
In the AAML study a set of relevant avionics analyses, mapped to the main satellite functions, were identified. In order to support modelling and analysis of the avionics system, a process based on three levels of definition was specified:
1) The avionics functional definition, used to design the avionics system as a set of avionics functions that communicate each other exchanging data.
2) The avionics logical architecture definition, that consists of a representation of how the system will be logically structured so as to fulfil the requirements and expectations of the users.
3) The avionics physical architecture definition, which comprises an allocation of logical components to physical components and the consolidation of the interfaces between components in their final form.
The three previous levels are complemented by an orthogonal one where the corresponding non-functional properties are specified.
This process provides the means to manage the different phases of conception and implementation of the avionics system as a sequence of subsequent refinements of the avionics definition.
The most noteworthy characteristics of the AAML modelling language are:
• The avionics analyses are performed based on the information extracted from the AAML model entities. This way, the model represents a single source of input for the various analyses, guaranteeing overall consistency.
• The language supports most of the developments across the different project phases and allows expressing the concepts of the avionics architecture in the model, keeping the best possible compromise between abstraction and precision.
• The language also supports the possibility of first providing a coarse-grained specification of the model entities and their non-functional properties, which can then be refined to introduce more details in the suitable consecutive project phase. This allows the user to perform an early coarse-grained analysis to obtain an initial set of analyses results, which is of great value for the so called “design space exploration”.
• The language accommodates a component-based design to allow developing a common library of COTS models for various architectural elements (e.g., buses, devices).
During the study an implementation of the Avionics Architecture Modelling Language and a sub-set of the relevant avionics analyses selected (in particular, the bus load and data latency analysis, the commandability and observability analysis and the on-board functions and performance analysis) was developed.
Additionally, a prototype tool was developed to conduct the system avionics definition process, to support the model definition and to execute the analyses. This prototype implementation was evaluated and tested by means of an use-case, based on the ESA’s Sentinel-3 satellite, consisting of an avionics architecture model developed using the AAML modelling language.
