According to the United Nation Environment Program (2005), “Marine Litter” is defined as any item that has been made or used by people and deliberately or accidently discarded either directly into the sea or coast or transported from land into the marine environment.

The performance of the future GNSS systems will be driven by more and more demanding applications asking for the ultimate accuracy in the most challenging scenarios and under every condition.

The incorporation of inter-satellite-links to the Galileo architecture is under detailed assessment by the GNSS Evolution Program, given its visible potential to:- Enhance the overall constellation command-ability- Enhance the overall constellation monitoring-ability- Simplify the Ground Segment, reducing the number of remote ground stations- Enhance the navigation message accuracy- Enhance constellation autonomyThe incorporation of inter-satellite-links to Galileo imply an important evolution of its functional and physical architecture.

The European space industry and ESA programs lack information on RF breakdown (Multipactor) when ferrites and dielectrics are used.

Background and justification:

A fibre-based deep space optical data terminal incorporates a seed laser, amplitude, frequency and / or phase modulator, optical amplifier and free-space beam forming optic. Provision is also made for coarse and fine pointing. For little additional Size Weigh and Power (SWaP), the architecture can be extended to that of a coherent Laser Imager Distance and Ranging LIDAR. Unlike conventional direct detection and photon counting schemes, it is relatively straightforward with coherent LIDAR to achieve quantum limited detection performance with unsophisticated detectors.

Bandwidth, frequency and power reconfigurable payload architectures are currently under development by major satellite manufacturers. Today's fixed bandwidth filters are a major bottle neck in such systems and have led to the implementation of reconfigurable filters. These new reconfiguration scenarios require flexible converters and, hence, flexible filters to be accommodated after the down/up conversion.

GNSS sensor stations, part of large GNSS infrastructure, provide the key inputs for the core processing facilities to compute orbit, clocks , ionosphere products and even integrity corrections.

Based on an ESA feasibility study, the Wavemill concept has shown that extremely interesting results can be achieved in terms of ocean current retrieval for both velocity and direction. There is a strong interest for optimising the antenna architecture and demonstrating feasibility and performance. Among possible antenna architectures, the javelin concept looks interesting since it can provide the required along- and across-track baselines with a compact spacecraft at launch having a nearly optimal configuration for AOCS (long and thin in flight direction).