The rapid expansion of the aircraft communications, with the aim to exchange navigation and maintenance data, internet services, ATM services, etc. requires the development of new tools and technologies and the improvement of the existing ones to optimise the communications management and reliability.
The modern researches in the field of the airborne communications mainly investigate the use of broadband ground/air/ground communications and air/satellite/air to achieve high data rate and secure data links. In the following paragraph the main work items will be described.
The ATENAA project focused on the possible role of civilian aircraft as nodes of an ad-hoc network, capable of multi-hop transmission over omnidirectional and broadband directional data links. The key technological components investigated were:
- aeronautical mobile ad-hoc network protocols;
- Ka-band phased array antennas;
- free-space optics for inter-aircraft communications;
- free-space optics for inside-cabin data distribution.
The project objectives can be summarised as follows:
- Objective 1: identification of areas of application for mobile ad-hoc networks in aeronautics;
- Objective 2: identification of MANET routing protocols suitable for aeronautical applications and relative assessment via simulations;
- Objective 3: methodologies and technologies to establish and maintain free space optics communication links between two platforms in relative motion, with identification of achievable performances;
- Objective 4: low profile and price competitive airborne Ka-band phased-array antenna design with steering capability, by adoption of promising technologies;
- Objective 5: feasibility study for a cabin free space optic system, which can deliver through diffused IR light, broadband communication to passengers;
- Objective 6: reduced scale validation platforms for testing the different technologies and assessing their capabilities;
- Objective 7: preparing a robust knowledge layer for subsequent related projects (e.g. MINERVAA).
The project performed research in the following areas:
- Defining the concept for a future networked avionic environment including both moving platforms (aircraft ant satellites), ground infrastructures and the related users and communications systems;
- Evaluating and developing the technologies needed for the networking and the security of the avionic network;
- Assessing a common set of requirements for the advanced technologies under investigation;
- Identifying Mobile Ad-hoc Network routing protocols suitable for aeronautical applications;
- Assessin HW technologies for Ka-band communications systems (with particular reference to TX and RX avionic phased array antenna realisation);
- Assessing HW technologies for Optical communication systems for outside-aircraft data links realisation;
- Assessin HW technologies for Optical communication systems for inside-aircraft broadband bus implementation;
- Testing and validating such emerging technologies against their applicability in the realization of broadband communication systems for the avionic networked environment;
- Dissemination of project results to a wider audience fostering the dialog with the research community and standardisation/normative bodies, trough journal publications, conferences, organisation of a workshop and a constant updating of the project web page;
- Subsequent sections describe in more detail the work performed and the methodologies and approaches employed.
Developing and refining the concept of a unified future networked avionic environment including moving platforms (aircraft, high altitude platforms and satellites), ground infrastructures and the related users and communication systems was the initial step in defining the MANET network. This allowed an assessment of a common set of requirements for the various platforms and allowed to evaluate the capabilities of each of them and their possible role in the network. This in turn was a stepping-stone for the identification of the advanced protocol and data link technologies that would be required to realise the aeronautical MANET. The evaluation of existing MANET protocol technologies needed for the networking of the avionic network has been the next step. The literature review and subsequent comparison with the defined requirements led to identification of several gaps, which required the inclusion of additional functionality.
In particular the ATENAA protocol stack includes a Data Link Selection sub-layer, which allows to logically separating the network layer from the different data-links layers installed onboard. a custom-tailored routing protocol (GeODV) has been designed, which combines the advantages of MANET reactive and proactive protocols, and takes advantage of the aircraft geographical position information expected to be exchanged among aeronautical nodes.
The developed protocols have been modelled into the OPNET network simulator and the simulation results have been used to provide proof of concept for proposed protocols. Additional work was aimed at providing security extension to the above-mentioned routing protocol. Initially the ATN security mechanism was analysed and it's suitability to the MANET environment was determined. This was done in conjunction with an overview of MANET-specific security requirements. Then a comprehensive review of MANET secure routing and distributed key exchange algorithms was made to determine if and which protocols are suitable for use in the ATENAA network. Appropriate protocols were selected and integrated into the GeODV. Finally the performance of these protocols was briefly investigated theoretically.
Detailed link-budget calculations have been carried out considering free-space loss, atmospheric attenuation, receive telescope aperture, turbulence induced fading loss, receiver sensitivity, beam splitting for PAT and data receiver, miss-pointing, tracking errors, and further losses.
Main technology aspects used for fre
High data-rate communications links are required in the future civil avionic environment to ensure passenger connectivity to their company VPNs, for in-flight entertainment and for secure and efficient ATM and fleet management. Existing radio-communication technologies are, to some extent, limited in bandwidth, capacity, data-rate, transmit-power and antenna size. A possible solution for these problems may be the applications of present systems with new-generation-wave links (Ka-band) and optical links and their overall integration in an avionic networked environment.
ATENAA project has strongly contributed toward enhancing the technological know-how of the European Industry, strengthening their capability to compete with US competitors.
The Consortium composition was consistent with respect to the above statement, thanks to the involvement of Industries, whose experience in the field guaranteed the exploitation of the project's results.
Moreover, the assessment of the potential obtainable performances constituting the results of ATENAA and the demonstration of the new technologies applicability may trigger the realisation of a new generation of avionic communication systems and, possibly, the adaptation of existing airframes or the realisation of new one. From this point of view, the European Aircraft manufacturing Industries strongly benefitted from the availability of the related know-how within the European Community.