Semiautonomous stationkeeping of geosynchronous satellites

The feasibility of semi-autonomous stationkeeping of geosynchronous satellites is studied, analyzing a + or - 1.0 deg longitude tolerance mission (FLTSATCOM) and a + or - 0.1 deg latitude and longitude tolerance mission (DSCS III). It is found that when the longitude tolerance is + or - 1.0 deg, semi-autonomous stationkeeping with a 10 percent maneuver uncertainty is feasible for a period of six months. For a DSCS III type requirement, the feasibility of keeping the longitude within + or - 0.1 deg depends largely on the longitude. Within 15 percent of all longitude regions, the number of maneuvers is less than three and autonomous stationkeeping is feasible under the assumption of low eccentricity. In other regions, where the number of required maneuvers is three or greater, the 10 percent maneuver error must be removed by an onboard accelerometer and the longitude error must grow linearly with time.