External dependencies: The resolution of some of the air interface open issues depend on the inputs from the industry which are yet to be consolidated. This includes for example requirements on voice and ATN/OSI interface or the security and safety requirements. For these particular issues the final conclusions cannot be reached within this study, but the way forward is detailed as much as possible at this stage.

Limited prototyping: For number of the addressed issues an extensive prototyping, simulations and technical validation would be required to reach the final conclusions. This includes for example the antenna design, voice service design or assessment of the transmitter spectrum mask feasibility. This is beyond scope of this study, but the project deliverables provide as many details for the potential follow-up activities as possible.

Portability to Inmarsat terminals: The AES prototype developed under the ANTARES project hosted the most demanding algorithms in the FPGA. On the other hand the existing Inmarsat modems use DSP as the primary signal processing component. Porting the complete ANTARES waveform to DSP is not affordable under this study and thus only the most critical elements are ported. The remaining DSP capacity is then assessed against the remaining algorithms.

Antenna requirements: To support connectivity through GEO constellation during aircraft banking, the AES antenna radiation pattern would have to be guaranteed for negative elevations (relative to airframe). This was highlighted as barely possible in the past and the problem is once again confirmed in this study.

Synchronization with Iris Service Evolution: The Iris Service Evolution (Iris SE) program was started under ESA after the Iris Convergence study was launched. The Iris SE program is now the governing program intended to define the long term evolution of the satcom safety services for aviation. The results of the Iris Convergence thus were presented to the Iris Service Evolution to provide additional inputs for the design and decisions making. Furthermore the avionics standardization support planned under Iris Convergence was re-directed to support the Iris SE program.