Maritime domain awareness builds on services and systems for interactive situation analysis and decision support to assist marine authorities in their assessment of unfolding situations to determine a response to imminent danger or threats to critical infrastructure or sensitive ecosystems. We propose here a methodical and economically viable approach to systematically develop an advanced situation analysis and decision support framework using formal engineering methods that facilitate continuous design through experimental analysis and validation of situation analysis process models in a realistic operational context. Striving for scalable and extensible solutions, our framework seamlessly integrates qualitative and quantitative modeling methods. An exploratory executable prototype operating on maritime surveillance data has been developed and is being evaluated, gradually extending the feature scope.