A novel safehold control law was developed for the nadir-pointing Vegetation Canopy Lidar (VCL) spacecraft, necessitated by a challenging combination of constraints. The instrument optics did not have a recloseable cover to protect them form potentially catastrophic damage if they were exposed to direct sunlight. The baseline safehold control law relied on a single-string inertial reference unit. A gyroless safehold law was developed to give a degree of robustness to gyro failures. Typical safehold solutions were not viable; thermal constraints made spin stabilization unsuitable, and an inertial hold based solely on magnetometer measurements wandered unaceptably during eclipse. The novel approach presented here maintains a momentum bias vector not for gyroscopic stiffness, but to use as an inertial reference direction during eclipse. The control law design is presented. The effect on stability of the rank-deficiency of magnetometer-based rate derivation is assessed. The control law's performance is evaluated by simulation.
A Gyroless Safehold Control Law Using Angular Momentum as an Inertial Reference Vector
AIAA GNC Conference ; 2008 ; Honolulu, HI, United States
2008-08-18
Aufsatz (Konferenz)
Keine Angabe
Englisch
Gyroless Satellite Angular Rate Estimation from Vector Measurements
British Library Conference Proceedings | 1998
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