Ephermeris table shows calculated positions of satellite and regular intervals of time. tracking stations
worldwide. global watch for satellite and addtional data for precise predition of orbit. orbits change only slightly over time.
ephemeris calcualted for each satellite.
Antenna pointing derived from ephermeris of satellite. computed for each ground station. Bearing and elevation of
satellite at planned time of acquisition permits antenna pointing.
Control center information set up communication link planning.
