A satellite antenna basically consists of a reflector and a feed. The reflector (dish) and the corresponding feed are built with respect to the specifications. Due to manufacturing tolerances the theoretical position of the feed does not completely fulfill the specifications. So relative movements of the feeds with respect to the reflector are necessary.
Alcatel Space has developed a new process for this optimization, called "Pathfinder System". After testing the feeds with their theoretical position, deviations are analyzed by software and hardware and the new optimized position for the feeds is determined. Pathfinder is fully automated. It controls two Physik Instrumente M-850 Hexapods to reach the optimized position of the feeds. The M-850 Hexapod is a complex six-degrees-of-freedom micropositioning system featuring better than 1 microns linear resolution and better than 5micro rad angular resolution in all axes. It also allows the user to define the pivot point anywhere inside or outside the system's envelope. Pathfinder drastically reduces testing time and increases performance, correcting deviations in pointing and gain with an accuracy of better than 0.01 mm and 0.001 deg. The new system has already demonstrated its full efficiency. More than 15 antennas have been optimized to date (1999).