ESA GNC Conference Papers Repository
AOCS FINE POINTING TECHNIQUES FOR ESA PLATO MISSION
Planned for a launch in December 2026, PLATO is the 3rd medium mission of the Cosmic Vision ESA program. Based on a payload consisting of 26 cameras that will look at transit of exoplanets in front of their stars, the pointing requirements of PLATO are very stringent. In order to fulfill the required pointing performances, the AOCS is relying on the use of a Fine Guidance System (FGS), which is part of the payload and on different fine pointing techniques, some of which were developed by Thales Alenia Space in the frame of PLATO. In the first part, the presentation will recall the objectives and constraints of the PLATO mission, while presenting the AOCS main pointing requirements (APE, MPE, PDE, RPE, performance in frequency domain) and the design of this payload in the loop AOCS. In the second part, the different fine pointing techniques will be presented. A focus will be done on the different Kalman filters used for the attitude and angular rates estimation, reaction wheels friction torque estimation, and also how the AOCS is compensating for misalignment between attitude sensors (FGS and Star trackers) and the effect of the kinematic aberration of stars on the FGS line of sight.