Object and ownership management in air traffic control simulations

We have developed a distributed air traffic controller simulator to study High Level Architecture (HLA) and services that are provided by the Runtime Infrastructure (RTI), especially Object Management and Ownership Management. In our simulation model, each airport is represented by a federate and controls a set of aircraft. The control of the aircraft is transferred among airports as the aircraft fly to different airports. In this paper we discuss two different approaches that we have used to facilitate federates to exchange the ownership of aircraft attributes, the pull and the negotiated push method, and present a comparison of these methods. We also discuss several problems we encountered while implementing these mechanisms and our approach to resolve them. We have experienced that in scenarios like ours, the push method is much more efficient and accurate. We have also noticed some shortcoming in the current RTI interface specification, as discussed in the paper.