Voice communication system for air traffic control - Development and evaluation of a prototype

Abstract: This report details the development and evaluation of a prototypical, Internet Protocol(IP)-based voice communication system (VCS) for air traffic control. Sucha system is concerned with connecting air traffic controllers to the radio which is used to communicate with aircraft pilots. Some benefits with a VCS are theintegration of telephone and radio services, recording of voice communications and data, retransmission on several radio channels. Using IP also entails interoperabilitybetween components of different manufacturers. The prototype was to be the smallest possible that could allow two users to connect simultaneously to a radio. Because of its safety critical nature, the requirements for a VCS arestrict, and documents from the European Organisation for Civil Aviation Equipment(Eurocae) were used as a basis for the specification. From the documents, a subset of the requirements concerned with the functionality for basic radio calls,communication initiation between the VCS and radio, performance of the system, and maximum allowed delays were chosen.
The radio gateway that was selected for the project did not fulfil several of thechosen requirements, since it was using an experimental firmware and was not developed fully in accordance with Eurocae’s specifications. To develop a fullfledgedsystem, a radio gateway in line with the required specifications must be used.
One part of the project was to test requirements concerning the maximum latency in the system. Different methods were used to measure the latencies. It was discovered that they sometimes show different results, which leads to theconclusion that care must be taken when deciding what measurement methods to use and how to use them.