SPECTRUM ANOMALIES ON SMALL SATELLITE LEO TO GEO RELAY LINKS

Abstract

Working in partnership, NOAA, NASA and EUMETSAT are investigating the feasibility of implementing small satellite remote sensing in low-earth orbit (LEO) that utilizes the Data Collection System (DCS) for data relay. The small satellite remote sensing platform would use a DCS transponder onboard the NOAA GOES spacecraft as a relay to earth for conveyance to the user. Two successful experimental payloads on two NASA Ames technology education satellites have been flown so far. The initial tests, while promising and meeting mission goals, have been impacted by spectrum anomalies, that appear alongside the desired signal in spectrograms. The characteristics of the anomalies suggest they are not generated by the spacecraft. The most likely explanation for their presence appears to be doppler-shifted, multipath earth reflections. This is believed to be one of the first cube satellite LEO-to-GEO-to earth relay links to be studied and the spectrum anomalies remain an open research topic.