Attitude Determination and Control System Characterization

Attitude Determination and Control System Characterization Nathan Barnwell, Sean Stanko, Dmitriy Obukhov, Stan Volchenok, Kevin Book, and David Wayne Objective: Simulate space environment on the ground to characterize nanosatellite Attitude Determination & Control Systems (ADCS) Satellite Attitude Control Background • Energizing a torque coil (electromagnet) produces a torque on the satellite based on local magnetic field • Accelerating a reaction wheel produces a torque on the satellite to control attitude • Often 3 (or more) of each are used to achieve 3-axis control • Torques produced by torque coils and reaction wheels are small in magnitude and challenging to observe on earth due to air currents, magnetic field, and friction NIWC Pacific ADCS Characterization Equipment • Torsion string has a low enough torsional resistance to observe reaction wheel and torque coil induced rotation about the torsion string axis • Three pairs of Helmholtz-spaced square coils enable 3-axes of magnetic field control to cancel out nominal magnetic field and create custom test scenarios Test Setup Results and Conclusions • Can produce magnetic fields ~3x greater than the nominal magnetic field in each axis • Field uniformity was sufficient for a 1U, but larger coils & cage would be required for larger systems • Even though torsion string enabled observation of rotations from torque coils, it was more difficult to observe than the reaction wheels • Could only observe relative rotation magnitudes • Evaluated polarity of reaction wheels & torque coils • Verified software assignments for each reaction wheel and torque coil Acknowledgments This work is supported by the Naval Innovative Science and Engineering program.

Acknowledgements

Naval Information Warfare Center (NIWC) Pacific provides technological and engineering support critical to information warfare for the U.S. Navy, as well as for Marine Corps, Air Force, Army and Coast Guard programs. Additional information can be found at:  https://www.niwcpacific.navy.mil

This work is supported by the Naval Innovative Science and Engineering Program.

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