This thesis describes the design and implementation of a real-time interoperative Air Traffic Control System Simulator (ATCSS) by applying the DEVS (Discrete Event System Specification) modeling framework and the associated simulation environment, DEVSimHLA.
The design and implementation has been done with the following steps. The first step is requirements analysis, in which domain experts and modeling experts discuss one another and make simulator specification from requirements. The next step is a design step, in which a simulator developer designs DEVS model defined in DEVS formalism and HLA (High Level Architecture) interface defined in HLA specification. And then a simulator is taken through an implementation process using the DEVSimHLA environment. Finally, the verification and validation process is followed. Specifically, the validation process includes testing of real-time requirement.
ATCSS operates in a set of PCs distributed in a network, which include a real machine such as the Main Control Station. Because the Main Control Station should be included in the simulation loop, ATCSS needs to operate in real time for each simulation loop. As an implemented result, simulation time increase as the number of simulation messages increase, especially flight information. In addition, ATCSS cannot meet the real time requirement even at the best time if there is more than 20 flight information. To support at least 120 flight information, which is a requirement this thesis proposes three schemes to satisfy the requirement.
The proposed three schemes are to draw changed data only, to draw filtered data with display resolution and to make message objects as a vectorized form. In real time tests, they show enough performance to guarantee that Air Traffic Control System simulator operates in real time under the 120 flight information.
DEVS formalism is used for specification of ATCSS in a hierarchical, modular form. Employment of the DEVS formalism not only makes the design of ATCSS systematic but also is efficient in implementation by using DEVSimHLA. DEVSimHLA is an extended version of DEVSim++, an implementation of the DEVS formalism in C++, to support HLA, which is a IEEE standard (IEEE 1516) for simulators interoperation.
