Framing and Synchronization of Satellite TTC Data

Communication between a satellite and a ground station is a complex process. It must follow standard space protocols. Small satellites need to exchange data over the space links, and at the same time, optimize the amount of data exchanged within the limited time of communication window with the ground station. As part of the ongoing work on BMSCE Upagraha, this paper proposes an optimized protocol for telemetry and telecommand communication, along the lines of CCSDS, using frame structures having much lesser redundancy than the existing protocols, like AX.25 and FX.25. The contingency decoder design is also presented. Simulation results show that this simplified protocol is useful for small satellites, because it uses smaller frame sizes; its throughput varies linearly with the payload size; and it uses lesser encapsulation data overhead as compared to existing standards.