The DAPHNE project is about photonic networks and components for aircraft. The project aims to exploit photonic technology from terrestrial communications networks and to identify and address technology gaps in implementing photonics extensively throughout the aircraft industry. The project brings together avionic equipment and aircraft manufacturers with photonic industry members and academic network specialists.
Aircraft data networks have increased dramatically in complexity throughout the history of powered flight. Modern networks must support many nodes with a wide range of span lengths, bandwidths and protocols. Existing systems, chiefly based on copper conductors, have evolved to support these ever-increasing demands. These networks have consequently become larger, heavier and more expensive, and this trend is set to continue. A coordinated step change to fibre optics would reduce network size, weight and cost and improve the modularity, flexibility and scalability. Moreover, fibre brings many other advantages including EMC immunity and improved security. By defining networks according to a DAL-based hierarchy, the flexibility of photonics can be harnessed within the constraints of safety certification restrictions. Terrestrial telecoms provides a rich source of technology. However, R&D is required to adapt terrestrial photonics for aircraft networks.
The primary objective of DAPHNE is to enable the full exploitation of terrestrial optical networking technology in future European aircraft and systems.
DAPHNE aims to increase the use of telecoms and industrial optical networking technology in future European aircraft and systems. Fibre optics and photonics offers obvious size, weight and bit rate advantages beyond aircraft systems state-of-the-art, but there are several other benefits:
- Excellent electromagnetic compatibility (EMC) due to the nature of the optical signal, without the need for heavy and bulky shielding;
- Increased functionality, e.g. wavelength division multiplexing (WDM), wavelength switching and optical-electrical-optical (OEO) conversion, potentially permit aircraft networks to be modular and reconfigurable;
- Hierarchical segregation: e.g. physical (multiple fibre), wavelength (single fibre) or temporal (single channel) allows novel modular network designs.
Cabin systems have been identified as the most immediate application area: here the need for high flexibility (driven by customization), high bandwidth (driven by information-to-the-seat) and large node count mean that the technology and business cases for photonics are compelling.
The project will adopt key component and network technology from commercial markets and develop and validate future aircraft networks to take European aircraft systems capability well beyond current state-of-the-art and be suitable as a platform for future development.
Fibre optics for aircraft data networks
Aircraft data networks have become increasingly complex over the years. EU-funded scientists developed fibre optics solutions that promise significant reductions in weight and size with enhanced functionality and modularity.
The copper wiring that forms the backbone of conventional aircraft data networks has evolved to meet needs. However, this evolution is accompanied by undesirable increases in bulk, weight and cost. Adopting terrestrial fibre-optic technology for aircraft applications would minimise these issues while increasing the modularity, flexibility and scalability of the network. EU-funded scientists initiated the project 'Developing aircraft photonic networks' (http://www.fp7daphne.eu/ (DAPHNE)) to pave the way.
Aircraft systems consist of numerous nodes, multiple transmission distances (span lengths) and bandwidths that can differ depending on the information transferred. In addition, different information with different levels of criticality (design assurance levels) is typically physically segregated, increasing cabling requirements. With photonics technology, the same network can support channel segregation to deliver the required quality-of-service characteristics for each individual channel.
Intensive research and development was supported by aircraft photonic network modelling tools adapted from commercial modelling software. Scientists delivered significant innovation at all levels consisting of the network, modules and photonic components. To speed certification and uptake, DAPHNE used a variety of commercial off-the-shelf hardware.
A number of new aircraft photonic network elements and technologies were developed, including integration of structural health monitoring data transmission. Researchers also provided the first demonstration of the use of a differential global positioning system carried over fibre optics for aircraft attitude determination. The team developed modular housing recommendations proposed as a new standard series for the aircraft fibre-optic networks, including design of cables and connector interfaces. Finally, DAPHNE developed more than 20 photonics components for aircraft use, many of which were tested within the scope of the project. These included couplers and splitters modified to withstand the harsh aircraft environment.
Scientists have provided important advances in techniques, reliability and standardisation of aircraft photonics networks devices and protocols. Work has led to about 50 presentations at more than 25 international conferences. The small field of aviation fibre optics has only two annual events worldwide and DAPHNE was an important contributor at both. Close ties with industry and standards organisations throughout the project should facilitate certification and market uptake of developed technologies.