By the end of 1995 the project had completed the first two of its planned three phases. These were an assessment of the requirements which form the main drivers for the ATN system design and the development of a catalogue of key inputs to the realisation of the future ATN.
The first phase made an assessment of the requirements that form the key ATN drivers. The philosophy taken was to combine the results of the more relevant work in this area into a single reference document. Both the airborne and ground network subsystems were considered. In addition an object-oriented requirements framework was developed and applied to the ATN. Although only partially complete this highlighted a lack of documented organisational drivers for the ATN. The work also considers the interoperability required by military organisations. The key results of the ATN requirements assessment were:
- that there is potential for extending the scope of the ATN to support a wider range of organisation and applications; there may be commercial impetus for this if the ATN is provided by a third party (an ATN Service Provider)
- that the key system issues driving the ATN design are mobility support, naming, dispersion of resources, safety and security
- that interworking with military ATC systems could be advantageous; in this case there is a need for secure gateways to the ATN
- a collation of the main requirements on the airborne and ground based sub-systems that will form the ATN.
The second phase of the project investigated a number of key areas that will contribute in different ways to the realisation of the ATN and covered:
- existing networks
- existing projects
- complementary standards and technologies.
Existing networks form a practical constraint on the deployment of the ATN. This indicates some of the development that will be required to enable subnetwork connectivity and interworking.
Fundamental to this is the ATN transition plan which was developed in the final phase of the project. A major input to the ATN realisation will be the contributions made by existing projects, in particular those based around ATN trials can be expected to provide experimental components for future ATN activities. The more interesting complementary standards and technologies are those addressing network mobility, security within a distributed system, network management and broadband services. These are all described and their applicability to the ATN discussed.
The work done compiling the ATN catalogue led to the following conclusions and recommendations:
- the key ATN system issues are addressed in other programmes in different ways which are often proprietary; opportunities for greater synergy of these with the ATN and re-use should be studied
- the ATN should be implemented in a phased approach, covering the organisations and applications to be supported including the development of interworking units with existing networks
- ATN management has only been addressed in a bottom-up fashion with little consideration for the organisation drivers
- the ATN concept is more advanced in terms of OSI networking, routing and connectionless services than other application domains.
The work has also resulted in an overview of previous and current ATN related projects and standards.
The Aeronautical Telecommunications Network (ATN) concepts have been developed over the last few years as a means to provide an integrated data communications service to the air transport community. These have focused on supporting ATC services and aeronautical operational communications (AOC) for the airlines. Based on the emerging concepts a whole range of standards work, studies and experiments have been initiated, each contributing in some way towards the realisation of an ATN. At the same time other European-funded programmes such as RACE have extended communications thinking towards broadband technologies with greater flexibility, integration and management. Also the Internet is providing improved access to information on a worldwide basis. The APAS PRESTATN project was set up in February 1995 with an objective to bring these together and determine the key work required in order that the ATN might become a reality. In particular the project was tasked with recommending key research topics, developments and experiments that are needed in the future.
GU14 6TD Farnborough