Enhancing Model-Based System Architecting Through Formalized Decision Management

System architecture decisions are typically informally captured in design documents. This practice leads to a loss of knowledge that impedes later activities like design changes, impact analysis, and reuse. Model-Based Systems Engineering (MBSE) frameworks support the development of increasingly complex systems but must address the problem of capitalization on architectural knowledge. To this end the "Decision Ontology for System Architectures (DOSA)"is developed to provide a formalized data model to capture system architecture decisions. DOSA is developed through a synthesis of decisions observed while developing an architecture model for a preliminary study of a novel satellite navigation system at Airbus Defence and Space. The approach is integrated into an MBSE framework enabling engineers to capture decisions that influence the architecture's characteristics while developing the system model and imminently trace decision to artifacts of the system architecture. Subsequent visual inspection and formal querying of the decision graph facilitates the analysis of made decisions, and their interrelations.