Platform performance factors affecting link budgets of geosynchronous communication satellites

Problems of maintaining the communication antennas pointed accurately and controlling the orbit parameters so that movement relative to the Earth is minimized, are treated. The OTS is used to illustrate how natural forces tend to depoint the satellite and also disturb the otherwise perfect geostationary orbit. Experiments on OTS to reduce the latitude and longitude station-keeping deadband to + or - 0.035 deg are discussed. Attitude variations of as little as 0.05 deg can be observed in signal strength measured at the Earth stations. Monitoring these variations can be used when large maneuvers are to be conducted for purposes like changing coverage, or antenna pattern mapping.