Engineering a System-of-Systems (SoS) solution for complex military problems introduces special challenges. While system engineering processes for the design and development of individual systems are relatively well-defined in DoD policy directives, engineering processes for a SoS solution are less mature and less tractable due to the reliance on existing system components developed according to a disparate set of requirements, that serve different users, and which were never designed to interact with other systems in a SoS context. Still, the realities of constrained budgets and the inherent complexity of modern operational strategies and tactics requires the seamless integration of multiple sensor, weapon, and communication systems to achieve the desired military capability of net-centric warfare in a joint operating environment.

The Navy's Triton Program (MQ-4C) is developing a high altitude, long endurance Unmanned Aircraft System that is required to operate safely and effectively in the vicinity of other air traffic. Triton depends on a layered defense strategy involving seamless interoperation of multiple Sense and Avoid (SAA) system elements as part of a larger Concept of Employment for strategic separation and collision avoidance. To verify that potential hazards in the Triton operational environment can be effectively mitigated, the Triton Program relies heavily on Modeling and Simulation (M&S) to generate evidence substantiating safety claims related to SoS performance. This paper focuses on the application of advanced M&S tools and techniques to support the Triton Safety Case. Special considerations for modeling overall SoS performance and behavior will be discussed, including issues related to the characterization of complex airspaces, runtime interaction among disparate system models, the role and relationship of constructive and virtual models in SoS analyses, the buildup from simulation to emulation to hardware-in-the-loop (HWIL) M&S, and VV&A of SoS representations.