On board communication subsystem for Sathyabama University nano-satellite

The primary goal of the communication subsystem of any satellite is to establish a communication link between the satellite and the ground station to relay payload and housekeeping data. In this paper, various hardware and software design aspects of the Sathyabama nanosatellite communication subsystem is discussed. Hardware devices chosen for our design includes Microhard MHX-425 ultra low power FHSS radio transceiver, Beacon transmitter, Microchip dsPIC on board processor and monopole antennas. The software written for the dsPIC processor is responsible for encoding telemetry and payload information into standard AX.25 format data packets as well as decoding commands transmitted from the ground station.