Agile AOCS definition for an optical Earth Observation mission: LSPIM

摘要

High-resolution Earth Observation Missions require a large agility of the satellite and a fine stability of the instrument line-of-sight in order to achieve high resolution performance and to meet the on-board multi-detectors registration requirements. For Land Surface Processes and Interactions Mission (LSPIM), the PROTEUS AOCS performance has been enhanced, thus developing an agile multi-mission AOCS based on gyroscope-startracker (GYR-STR) attitude estimation and reaction wheel (RW) actuation that meets both the slew capability (2.2°/s~2 angular acceleration and 1.5°/s rotation rate) and the high stability required. The satellite architecture is based on a system optimisation: minimisation of the inertia and maximisation of the flexible mode frequencies of the solar panels. The main features of the control are: 1. The attitude target generation is performed on-board and fulfils both minimisation of the control torque and flexible modes excitation constraints. 2. The attitude control includes feedforward command and estimation and compensation of gyroscopic torques. 3. The attitude control provides full high accurate stability (2.2. 10~(-4)°/s over 2s) and pointing performance (0.02°) less than 3 s after attitude manoeuvres.