Objective of the activity is to develop and validate a scalable, generic and flexible payload architecture for enhanced capacity, low earth orbit broadband multimedia missions based on active array antennas.
Targeted Improvements: Enabling technology developmentto increase the readiness to implement highly flexible, enhanced capacity, low earth orbit, broadband multimedia missions using active array antenna technology.
Description: In recent years there has been a surge of interest in low latency, global broadband access provision via constellations of low earth orbit satellites. First generation systems feature rather simple and conventional bent-pipe repeaters and passive antennas and, by necessity, exploit existing technology that is compatible with near-term missions. This near-term approach inherently entails compromises in terms of system performance and payload resource allocation flexibility.
For next generation systems there is a strong drive towards lowering the cost of satellite capacity in orbit still further, which implies a step change in raw system capacity as well as significantly improved payload performance and resource allocation flexibility. These enhancements move well beyond what is achievable with todays payload technology.
The highly dynamic nature of the communication links in a non-geostationary satellite orbit, both for space-to-ground communication and for communication between satellites withinthe constellation, suggests the use of electrically steerable beams (active array antennas) and on-board digital processing. With regard to the latter, the capacity of critical communication links could be significantly improved by regenerative processing, raisingthe possibility of partial regenerative processing and a new class of hybrid transparent/regenerative digital processorfor such applications. Whatever the mix of the technology, the solution must support the business proposition of the system operator and serviceprovider.
The payload design will be driven by the specific characteristics of low earth orbit applications, includingfactors suchas the orbit dynamics, mission lifetime, platform constraints on payload mass, physical size and allowable thermal dissipation, antenna field of view, coverage size and dynamic beam steering requirements and the radiation environment. These factors will be specified at initiation of the activity and in turn will drive the development of the enabling technologies for such applications.
In viewofthe significantly shorter satellite lifetime in comparison with geostationary satellite systems, and the continuouscycle of satellite replenishment, more frequent opportunities exist for system and payload improvement in low earth orbit systems, which at the sametime reduces the time to market for new innovations.
This activity aims to bridge the technology gap between the first generation systems now being deployed commercially and future satellite payloads offering significantly enhanced capacity and flexibility forlowearth orbit broadband multimedia missions.
As a first step, a generic and scalable flexible payload architecture based on active antenna technology will be designed and optimised, taking into account aspects such as the beam forming network architecture, the digital signal processing architecture, the high power amplification sizing, the management of beam weights, system and payload timing references, the thermal management, payload reliability, and the spacecraft accommodation constraints. The outcome of this first stepwill be a reference flexible payload design with an associated technical specification, flown down to equipment specifications for the major elements of the payload.
Subsequently, a proof-of-concept breadboard will be developed and validated, ina configuration sufficient to demonstrate the functionality of the flexible payload architecture and to verify its performance in terms of both spatial and temporal in-orbit flexibility. The breadboard shall coomprise representative payload building blocks, including frequency conversion, signal processing, traffic routing, beam forming, high power amplification, filtering and radiating element functions.
Constraints and limitations identified in this activity will serve as valuable inputs to technology road maps for future low earth orbit broadband satellite communication systems.