| 摘要 |
<p>AUTONOMOUS STATIONKEEPING FOR THREE-AXIS STABILIZED SPACECRAFT Apparatus for autonomously performing stationkeeping maneuvers for three-axis stabilized spacecraft (1) such as geosynchronous satellites. For each of one or more spacecraft axes (y, z) the invention autonomously performs desaturation of a momentum/reaction wheel (31-32, 41, respectively) associated with that axis, while simultaneously accomplishing the preselected compensation of the spacecraft's east-west position. Thrusters (35-38, 45-48) having a polarity corresponding to the desired desaturation polarity are fired in a particular sequence: when a preselected east-west firing bias is present, the thrusters fired are solely from that face of the spacecraft (1) needed to counteract the east-west deviation. After the bias has been worked down, thrusters are fired from alternating spacecraft faces. An open loop portion (63-74) of the instant circuit performs or completes working-down of the east-west firing ??as once per preselected firing period in those cases where the desaturation maneuvers are not sufficient to perform this function by themselves.</p> |
