Project update 35 of 35
Greetings from Moscow. We are the LEO-SDR project team. LEO stands for Low Earth orbit, so we’re simply a team of students in Youth Space Center of Bauman Moscow State Technical University involved in designing cubesats (very small and relatively cheap satellite, consisting of multiple 10x10x11.35 cm3 cubic units).
Our current challenge is developing a high-performance, flexible communication and storage system for cubesat, including a baseband processor combined with SSD storage and an RF front-end module. Specialized satellites with such system as a payload can be used for many different missions: in-situ EMC and propagation research, SDR-on-orbit HAM receiver, "a space router" for a swarm of research or commercial cubesats, or even something like inter-satellite internet (with a large constellation).
The XTRX is the key component of the baseband processor. Its very wide bandwidth and frequency coverage allowed us to simplify the front-end while its embeddability relieved us from the need to develop a custom, application-specific SDR.
The main design idea used in the LEO-SDR core board is to connect XTRX to both a Cortex-A53 and an NVMe SSD via PCIe bus. This solution should enable XTRX’s FPGA to work with the SSD directly, recording even full-bandwidth I/Q streams while bypassing processor. That’s very important to satisfy the severe power constraints of a small satellite since it allows most of the DSP and packet processing work to be done by the FPGA, only using the ARM for some heavy and non-trivial algorithms.
Our next step is to get more familiar with the XTRX FPGA, specifically with how to implement code for optimized PCIe data transfer.