Data and Phase Links
The maximum scientific data rate of downlink is 128 Mbit/s (total rate 144 Mbit/s). Data transmission is being done by VIRK communicationsystem through the high gain antenna at frequency 15.000 GHz. The downlink data stream is divided into frames each being 20 000 bytes long. Every frame contains the header of 30 bytes long, which is placed at the beginning of each frame. VIRK provides also two-side coherent link (phase transfer) at 7.207500 up / 8.400 down GHz, (fup/fdown) = 961/1120. Reference signal for SRT is derived by H-maser on tracking station using also predicted navigation data.