Evolutionary adaptation of ATM systems for SWIM

Air Traffic Management (ATM) has embraced the concept of System Wide Information Management (SWIM) as the means to improve data exchange between various applications in different domains such as flight data management, weather and aeronautical information management. Even though SWIM definitions in the US and Europe put emphasis at different aspects in their NextGen and SESAR (Single European Sky ATM Research) programs, the transition phase towards SWIM-enabled systems will pose similar challenges for both program initiatives. Most existing ATM systems have been designed with interfaces for specific data exchanges limited by proprietary data formats and protocols. The SWIM paradigm enables legacy systems - when adapted to new interface technologies - to be connected to new information and service users and thus impacts the life cycle of highly valuable assets. The paper outlines a stepwise approach for adaptation and evolution of systems to enable their connection to a SWIM infrastructure that follows a service-oriented architecture. We show how the models and technology selected impact the engineering of the adapters between existing legacy applications and the target infrastructure. The approach also touches nonfunctional aspects including security. Using two case studies derived from recent work with Air Navigation Service Providers (ANSPs), we discuss the evolution steps in practical examples and describe successes and pitfalls encountered so far: One case study illustrates how the system interface of the European AIS Database evolves moving from a pure JMS messaging based solution towards a service enabled approach using mainstream web services to guarantee compliance with new interoperability requirements. The second case study describes the design and development of an adapter component that connects a backend system providing VT100 interconnections for input and output streams with a SWIM message bus that completely hides all communication complexity behind XML messages. The case studies demonstrate that the system evolution process towards SWIM is driven both bottom up (from the existing applications) and top down (by standardization institutions as well as industry). Information and services provided by existing systems are valuable assets which in course of the system evolution can be maintained when properly encapsulated and hidden behind service façades. Our paper provides an outlook on the evolution towards SWIM from an ANSP's perspective as well as from an industry viewpoint. This decade will see a substantial change of the way ATM systems interact. Our approach should support decisions on how to make existing infrastructure ready for SWIM and when to launch programs to build new generation components that natively f it into the information sharing infrastructure.