With the transformation from the traditional document-based systems engineering (DBSE) to the model-based systems engineering (MBSE), it becomes more and more difficult for the "Vee" process model of the DBSE to reflect the characteristics and the requirements of the system of systems (SoS) engineering. Based on the analysis of the SoS engineering (SoSE) process models and their shortcomings, this paper takes the capability as the invariant feature in the system requirement analysis, the design, the verification and the evaluation. The architecture with its prototype is selected as the connector of all activities of the SoSE. A ring model for the SoSE process is proposed and analyzed from the viewpoints of the time, the capability and the architecture. The results of this paper could be used for understanding the SoSE process, establishing the architecturecentric SoSE theory and guiding the SoSE practice.

system of system  /  SoS engineering process  /  capability-based  /  architecture-centric  /  time viewpoint