Elementary Magnetic Attitude Control System
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A three-axis closed-loop attitude control system for Earth observatory momentum bias spacecraft is proposed. A horizon scanner and magnetometer are employed to measure attitude errors; no yaw sensor is required. Appropriate control signals are generated and used to command variable strength electromagnets, which interact with the geomagnetic field to reduce observed errors. This system provides for initial acquisition, precession control, nutation damping, and pitch axis momentum control. All functions are performed autonomously-no ground station interaction is required. Analytical expressions predicting system response are compared with numerical solutions of the governing equations, and with the results of the application of Floquet theory. Good agreement is obtained. The control concepts are straightforward and can be implemented with a minimum of hardware. Three-axis control accuracy on the order of one-half degree may be expected in typical applications. © American Institute of Aeronautics and Astronautics, Inc., 1976, All rights reserved.
author list (cited authors)
Stickler, A. C., & Alfriend, K. T.