Low Earth orbit microsatellites for data communications using small terminals

For more than a decade SSTL/UoSAT has been pioneering the use of microsatellites in low Earth orbits. Simple, efficient and low cost digital 'store and forward' communications systems are a key element for a successful microsatellite mission. These communications payloads now form the basis of the communications links for both experimental and operational microsatellite missions and perform a range of missions from remote sensing data transfer and experimental data downlinks to remote site data collection and messaging. This paper assesses the performance and capabilities of the most recently launched digital store and forward payloads on SSTL/UoSAT microsatellites. Increasing levels of interference in the WARC-92 'little LEO' band have a large impact upon the design and performance of the microsatellite communications system, particularly for communications with small terminals. Coupled with the constraints of the small microsatellite platform innovative solutions have been adopted to optimise throughput to small terminals. Measurements of the global interference environment in these bands have been made using microsatellites equipped with store and forward transponders.<
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