Geostationary satellites orbit the Earth in sync with the Earth's rotation. This may cause it to appear stationary in space , however, natural disturbances such as gravitational effects associated with the Earth, sun and the moon as well as station-keeping maneuvers cause the satellite to drift around its orbital slot.
A satellite Center of Box is defined as Longitude ±0.005° and Latitude ±0.005° of its orbital position. If a satellite moves within this range, the Earth station antenna can use the Center of Box predictions to align the antenna for optimal signal quality. It is recommended that antenna isolation and pointing adjustments be carried out when the satellite is in its Center of Box for peak performance.
Schedules indicated below are in GMT.
Center of Box information for ABS-1
| 03/25/08 18:34:19 | Entering Limits of Center of Box |
| 03/25/08 19:59:17 | Exiting Limits of Center of Box |
| 03/26/08 18:19:11 | Entering Limits of Center of Box |
| 03/26/08 19:53:43 | Exiting Limits of Center of Box |
| 03/27/08 18:54:56 | Entering Limits of Center of Box |
| 03/27/08 19:22:25 | Entering Limits of Center of Box |