The objective of the activity is to develop and validate a scalable, generic and flexible payload architecture for high capacity geostationary broadband multimedia missions based on active array antennas and suitable for use in a beam hopping system.
Targeted Improvements: Enabling technology development to increase the readiness to implement highly flexible, high capacity, geostationary, broadband multimedia missions using active array antenna technology and beam hopping techniques.
In recent years the commercial satellite market has been evolving rapidly. Satellite operators now recognise that the high degree of in-orbit coverage flexibility provided by active array antennas is an enabler for their business models, providing the service flexibility needed to adaptto changing commercial conditions and to seize new business opportunities. At the same time, there is a strong drive towards lowering the cost of satellite capacity in orbit, leading to the emergence of high throughput systems featuring large numbers of beams.
As the number of beams increases, allocating capacity to beams according to need becomes increasingly difficult and inefficient in the frequency domain. This has led to a strong interest in techniques for capacity allocation on a time basis, in particular beam hopping. In addition to providing spatial (geographical) coverage flexibility, active antennas are well suited to applications requiringtime-dependent payload resource allocation.
The first commercial applications of active antennas seen in recent years are limited to a few beams only, exploiting existing technology that is compatible with near-term missions. Current active antenna technology andthe associated flexible payload architecture require significant further development to be able to accommodate the much higher number of beams demanded by high throughput systems in an efficient and scalable manner. The flexible payload architecture must be able to support beam hopping applications, "smart gateway" techniques to simplify the ground segment, gradual deployment of the gateway earth stations during service roll-out and an efficient site diversity and earth station redundancy schemes.
The payload design will be driven by the specific characteristics of geostationary broadband multimedia missions, including factors such as the mission lifetime, platform constraints on payload mass, physical size and allowable thermal dissipation, antenna field of view, number of beams,beam size and inter-beam isolation requirements, dynamic beam steering and beam hopping requirements, and dynamic capacity and payload management needs. These factors will be specified at initiation of the activity and in turn will drive the development of the enabling technologies for such applications.
This activity aims to bridge the technology gap between the small-scale flexible payloadsnow being deployed commercially and future high capacity geostationary satellite payloads for broadband multimedia missions with demonstration focused on the transmit section. As a first step, a generic and scalable flexible payload architecture basedon active antenna technology will be designed and optimised, taking into account aspects such as the beam forming network architecture, high power amplification sizing, the management of beam weights, the timing sub-system for beam hopping, the thermal managementand the spacecraft accommodation constraints. The outcome of this first step will be a reference flexible payload design with an associated technical specification, flown down to sub systems and equipment specifications for the major elements of the payload transmit section (from the downconverter outputs up to the active antenna feeds).
Subsequently, a proof-of-concept breadboard will be developed and validated, in a configuration sufficient to demonstrate the functionality and scalability of the flexible payload architecture and to verify its performance in terms of both spatial and temporal in-orbit flexibility. The breadboard shall comprise representative payload building blocks, including (fast) switching, beam forming, high power amplification, filtering and radiating elementfunctions. Constraints and limitations identified in this activity will serve as valuable inputs to technology road maps for futurehigh throughput geostationary broadband satellite communication systems.