ASCAT Satellite Calibration Transponder for the European Space Agency

The ATP1 precision Az-El pedestal was selected to provide the satellite ground segment tracking platform for calibration trials by ESA. In this application the pedestal provides real-time tracking of the LEO satellite according to a programme track table downloaded beforehand.

The payload is a horn antenna with associated rx/tx electronics enclosure, and interconnecting waveguide. Prime considerations in selecting the ATP1 was its ability to provide high positional and timing accuracy (better than 0.2° and 10mS). In actual performance trials the ATP1 comfortably exceeded this requirement, achieving positional errors of 0.02° and timing synchronization within 0.2mS!

Other ESA requirements were that the ATP1 should have a service life of 15years, be capable of operation totally remotely (with the operator as far as 900km away!).