Satellite Front-End Equipment Based on Consumer Off-The-Shelf Single-Board Computers

Abstract: This Master thesis project consists of the exploration and potentially the design and implementation of an Front-End Equipment (FEE) device based on the Beaglebone Black or similar single-board computers. During development and testing of a satellite system, FEE serves to adapt telemetry and telecommand data streams between a satellite and the ground- control system. At OHB Sweden there exist FEE solutions based on old Rabbit processor modules. The two main functions of an FEE device are to forward telemetry data from a satellite to the ground control, and forward telemetry commands from the ground control to the satellite. This thesis explores if it is technically possible and economically feasible to build FEEs from consumer off-the-shelf electronics, and if a similar or better performance than with specialised equipment can be achieved. A prestudy carried out by OHB Sweden showed that the Beaglebone Black is promising, mainly favoured by its two Programmable Realtime Units (PRU). The functions of downlink and uplink are implemented, benchmarked and compared against the project's transmission speed goal. In both cases the speed was greatly affected by the concept of transmission: When the main work was done by the PRU then the overall transmission speed was higher. By having the main task done by the PRU the number and size of messages from PRU to host (vice versa for uplink) can be decreased. The Host-PRU communication is the system's bottleneck. The initially seen potential of the BBB, cannot be confirmed nor refuted completely.