Design and performance of the ESA optical ground station

The European Space Agency (ESA) has undertaken the development of Optical Data Relay payloads, aimed at establishing free space optical communication links between satellites. The first of such systems put into orbit is the SILEX project(1), in which an experimental link between a GEO satellite (ARTEMIS) and a LEO satellite (SPOT IV) will be used to relay earth observation data. In order to perform In Orbit Testing (IOT) of these and future optical communications systems, ESA and the Instituto de Astrofisica de Canarias (IAC) reached an agreement for the building of the Optical Ground Station (OGS) in the IAC Teide Observatory, which consists basically of a 1-meter telescope and the suitable instrumentation for establishing and testing bi-directional optical links with satellites(2). The presence of the atmosphere in the data path posses particular problems, with an impact on the instrumentation design. The transmission, reception and measurement functions, along with the overall control of the instruments, are performed at OGS by the Focal Plane Control Electronics (FPCE). The design and performance of this instrumentation is presented, emphasising the Pointing, Acquisition and Tracking, the Tuneable Laser and the Master Control.