Formation Flying Radio-Frequency metrology validation and performance: The PRISMA case

The Radio-Frequency (RF) metrology sub-system developed by Thales Alenia Space© under contract from French (CNES) and Spanish (CDTI) space agencies provides autonomous relative positioning for high-altitude formation flying missions, where Global Navigation Satellite System (GNSS) services are not available. The RF sub-system basically provides navigation products such as relative distance, Line-of-Sight (LoS) and velocity estimates over a wide relative distance range starting from three meters and up to 30 km. It allows full-space coverage thanks to multiple antennae and offers an Inter-Satellite communication Link (ISL) featuring a 12 kbps throughput.The first two Flight Model (FM) units have been delivered at the end of 2009 in the framework of PRISMA flight demonstration mission. Thales Alenia Space© performed the integration and validation of the units in the conductive mode, covering functional and performance aspects. A complementary validation phase was achieved by CNES in radiated conditions, including multi-path and antennae phase center characterization in anechoic chamber.

► An overview of the FFRF metrology is presented.
► The validation scheme and first performance results in both conducted and radiated conditions are examined.
► Despite a high degree of complexity, functional and performance results are very encouraging for the future.