01 Jul 2002
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IFMS equipment
The European Space Agency has for many years funded the construction and launch of satellites and space vehicles for scientific purposes.
Each of these requires a control and communications link, and over the years the Agency has operated a number of such legacy systems in parallel, each requiring its specialist support.
The ATC is now delivering to the Agency a new generation of equipment for installation in their earth stations, which will replace the existing systems, and provide the link with future space vehicles. The equipment, known as the 'Intermediate Frequency and Modem System' or IFMS, provides a maximum of flexibility in the link by extensive use of re-programmable hardware (fieldprogrammable gate arrays) and software (general purpose processors and programmable signal processing chip sets) in both its signal processing and data processing sub-systems.
Remote operation of the IFMS equipment in sites around the world is a key factor in the design, enabling the Agency not only to control spacecraft, but also to load new software and re-program the IFMS hardware from its European headquarters.
As well as transmitting and receiving data, the IFMS equipment provides a highly accurate measurement of range to the space vehicle, typical accuracy being a few cm. In addition controlling all existing Agency space vehicles, the IFMS will play key roles in the forthcoming 'Mars Express' and the 'Rosetta' mission to comet Wirtanen. In the comet mission, the Rosetta spacecraft will travel for over eight years, to rendezvous and land on Wirtanen in 2011 somewhere around the orbit of Jupiter. Throughout its flight it will be controlled and communicate via the IFMS.
The IFMS is, in essence, a radio which can change its modulation scheme under software control. A similar capability is required of military radios, which need to be able to cope with a variety of communication networks. The experience gained from IFMS is of direct relevance to the C4ISR community.
