Arraying Technique for Enhanced Multiplexing of Interferometric Signals (ARTEMIS): An Enabling Technology for Long Range or High Data Rate Microspacecraft Communications

The Space Flight Laboratory of the University of Toronto Institute for Aerospace Studies has developed a prototype ground station antenna array correlator that offers advantages over previously employed approaches for weak signal communication. By using Orthogonal Frequency Division Multiplexing (OFDM) in the microspacecraft transmission, the array can perform frequency correlation in addition to time correlation (both techniques derive from Very Long Baseline Interferometry) to bring all the signals of the array into alignment. This removes the need for high accuracy local oscillators, such as hydrogen masers, to be used at each antenna to maintain frequency stability. In essence, expensive hardware requirements have been replaced with inexpensive software algorithms, allowing for the construction of low-cost ground station arrays made up of small antennas (eg. 3 m or 6.1 m diameters), perfect for use as a microsatellite ground station with a high data rate link, higher than what is currently possible. Recent hardware prototyping results have confirmed those obtained previously through simulation alone. These new results will be discussed and it will be shown how a small-antenna array ground station could be used to provide a high performance communications link for future microspacecraft missions flying to the Moon and other planets and bodies in the Solar System. The paper will also describe a planned flight demonstration mission currently being arranged through the Space Flight Laboratory’s CanX nanosatellite program