Today's technologies used in aeronautical communications have limited capabilities both on data rate transfer and on internal and external aircraft networking. MINERVAA aimed to be a fundamental step on the roadmap to the implementation of the future aeronautical broadband network. The project applied the paradigm 'bringing the technologies from the lab to the aircraft'. MINERVAA validated in-flight the outside-aircraft optical link technology and on a fully representative aircraft mock-up, several Inside-aircraft optical link specific applications. The project also further developed the basic research on Ka-band avionic phased-array antennas, already carried out in ATENAA to a further extent.
The project aimed at the validation on aircraft and in-flight of free space optical communications technologies and to continue the basic research on some specific technological areas in the field of Ka band antennas.
Namely, the network components MINERVAA focus on were:
- Outside aircraft optical link (OOL);
- Inside aircraft optical passengers network (IOPN);
- Ka band data link based on avionic phase arrays.
Those innovative technologies were selected as key elements in the prospective of achieving wider bandwidth with respect to other state of art communications technologies. Moreover, as well known, optical connections ensure lower level of interference with other on board equipment. Ka band antennas are the most suited for on board installation versus available bandwidth and physical size.
In order to achieve these objectives, the project was structured into Work packages (WP): three technical WPs (WP2000, WP3000 and WP4000), one demonstration WP (WP5000), 1 dissemination WP (WP6000) and one management WP (WP1000). The WPs are sub-divided into tasks.
WP1000: The project management included effective leadership, provision for monitoring processes and budget expenditure, and ensuring that all deliverable were received on time and to specification. Within this WP, internal processes such as communications to the CEC were managed.
WP2000: This WP was devoted to design, develop and validate an outside-aircraft optical link with the following characteristics:
- higher data transmission rate (at least 100 Mbit/s, target 500 Mbit/s);
- higher range (at least 12 km, target 25 km);
- capability to operate in-flight and provide broadband connections between aircraft and / or high altitude platform and / or satellites.
For this technology to be practically viable for aircraft installation, the following constraints were taken in account:
- high safety (including eye-safety in this specific case);
- high availability and reliability (i.e. capability to provide stable and continuous performance);
- limited installation impact (low mass, aerodynamical drag, power consumption, etc.);
- low life cycle costs, easy upgradeability, limited maintenance.
WP3000: This WP was based on the creation of an innovative wireless optical in-cabin link to serve health monitoring application as well as safety and security in cabin systems. Further research on wireless optical modulation schemes for further evolvement of the wireless optical physical layer has been carried out. The health monitoring systems along with the safety and security system application have shown the possibility of increasing in-flight safety by minimising cost and crew workload.
WP4000: An integrated Rx/Tx Ka-band phased array antenna has been designed and a 1/4 scale test bed realised and measured. Test-bed EIRP is comprised between 18.7 +/- 0.5 dBW and 19.8 +/- 0.5 dBW, test-bed gain is larger than 18 dBi, and steering capability is more than +/- 36 degrees at -3 dB level.
WP5000: The creation of the flight certification documentation for the airborne terminal of the outer optical link was carried out with success. Furthermore, the in-flight-validation was executed and a total of thre
Comparison of expected results and achievements is presented by work packages:
The goals, that were expected to be fulfilled, could mainly be achieved. Most of the system’s functionalities, as e.g. the RF Link for GPS-Position- and Video-Transmission, the communication system, the pointing, acquisition and tracking of the Airborne Terminal could be demonstrated during Ground-Tests and the In-Flight-Validation. Due to a very demanding time-schedule in the integration phase, the algorithms regarding the closed-loop tracking of the Airborne Terminal could not be fully verified. This led to the unfortunate fact that a stable communication link could only be shown during ground tests and not during the few In-Flight-Validation Flights. However, the principal operability of the system was shown.
The achievements correspond to the expected results. More publications were published than expected, also in other areas like medical measurement.
Thermal considerations had to be considered. The test-bed design allows nominal behaviour with simple forced air at 25°C: no liquid fluid cooling is required. The design is therefore successful on a thermal point of view.
It is achieved, within the MINERVAA project, to keep a single low profile active layout instead of multiple connected modules, to deal with thermal dissipation through HPA careful relative placement and configuration, thus obtaining a highly integrated antenna with a good efficiency (EIRP and dissipated power are in-line with objectives). The main Tx efficiency loss is due to the HPA efficiency itself, as the active panel combiners, phase-shifters and attenuators are at low microwave level.
Satellite to mobile link up to 432 kbps per channel on the move is now available with Swiftbroadband® from Immarsat, but still in low frequency band.
On the Ka point of view, the Hylas 1 and W3B will provide some Ka capabilities and will be launched at the end of 2010, and the KA-SAT satellite will be launched for Eutelsat at end 2010 or beginning 2011 for providing high speed internet, HDTV, 3DTV, Tooway® Eutelsat service to Europe.
These capabilities and the ATENAA project results would give satellite to aircraft capability. MINERVAA provided the basis for the complementary link tools, with OOL link for very high speed link between two aircrafts and Ka link for high speed link between several aircrafts within a MANET network.