XBDL | ESA CSC

Status

Completed
Status date

2019-01-28
Activity Code

5D.031

Objectives

The project was developing an X-band transmitter (8.025GHz to 8.4GHz) using a high-speed baseband processor, coded and modulated to the latest CCSDS standards, in a compact highly integrated and power efficient design. The modulation drives a nonlinear SSPA followed by an integrated post-amplification RF shaping filter (as specified by ECSS-50-05C). Such an approach offers high efficiency at high data rates with low risk. In addition to this mode of operation, the system architecture readily supports linear modulation scheme such as QPSK.

To meet parallel to serial data stream processing as well as baseband processing the intention is to leverage the latest commercial FPGA technology, including commercial IP cores where needed.

The project took an evolutive approach that allowed a stepped development to more advanced coding and modulation techniques.

The result was a more flexible, software configurable product designed to give mission assurance with optimised cost of ownership for the evolving small sat world.

Picture credit: COM DEV Europe Ltd, Heritage C-band product

Challenges

The key challenges were in appropriate component selection for the given design philosophy and the system architecture choices to meet the exacting radiation, thermal, mechanical and electrical environmental factors, while maximising product functionality and configurability. Key experiences in flexible TT&C and heritage flight datalink products, where pragmatic qualification approaches were validated were essential to development success. Our development also required inputs from as many potential users as possible to ensure that its capabilities meet customer needs.

Benefits

The software defined architecture allowed for reconfigurability and fine tuning to individual end customer needs. Software configurability also enabled:

flexible modulation
flexible data-rate
flexible output power

Connecting the baseband processor directly to an X-band modulator and subsequent high power high-efficiency GaN based power amplifier delivered savings in mass, power and volume.

Software defined radio (SDR) based implementation
Non-ITAR commercial-off-the-shelf (COTS) components
Low mass and low volume unit
Programmable output frequency
Selectable coding
High efficiency Gallium Nitride (GaN) amplifier-based design for low power consumption

This solution was aimed at missions in low earth orbit (LEO) with a balance of affordability, flexibility and total cost of ownership in mind, enabling smaller, lower cost, more agile platforms in our evolving industry.

Features

Units were built in accordance with ECSS class 3 (NASA level 2) standards, taking a radiation tolerant, rather than radiation hardened, approach to deliver mission assurance.