Attitude Determination and Control (ADCS)

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Optical Communications
Part of the Optical Communications series
Team Goals
Amateur Optical Communication RecordCubeQuest Challenge
Equipment
OpComms System ISystem IISystem IIISystem IV3 cm Board
Noteworthy Tests
SSI-1E4Test Procedure
Important Concepts
The Field of Optical CommunicationsBeam DivergencePulse Position ModulationScintillationPrecision AimingFogLong Range RFOptical Internet BackhaulSignal-to-Noise Ratio
Field Test Locations
W6YX (also see Amateur Radio) • Skyline Boulevard OverlookProposed Alternate OpComms Test Sites
People
Dr. Simone D'Amico (Team Advisor)Elizabeth Hillstrom (Co-Lead)Sasha Maldonado (Co-Lead)Dr. Joseph KahnDr. Leo Hollberg
Optical Communications Satellites
FitSat-1LADEEARTEMIS and SPOT-4OICETSOPALSJPL 1U Optical Communications Terminal
Astronomy
Las Cumbres Observatory Global Telescope NetworkStanford Astronomy ClubStanford Student Observatory
Miscellaneous
Tactical Cinderblock
VE

An Attitude Determination and Control (ADCS) provides measurements regarding a satellite's orbit and allows the satellite to change its inertial position.

Examples of ADCS Hardware

  • Most ADCS hardware relies on an ability to change the satellite's position relative to the Earth.
    • Reaction wheels: Using small, spinning wheels, reaction wheels allow satellite positioning using the principle of conservation of momentum.
      • CubeADCS: CubeSpace's CubeADCS utilizes a variety of sensors (including magnetometers and sun sensors) to accurately determine the satellite's precision. It can use either magnetic torquers (see below) or reaction wheels for attitude determination.
    • Magnetorquer: By creating a magnetic field that interact's with the Earth's own magnetic field, a magnetic torquer produces a force that can rotate a satellite.
    • Control Moment Gyros: Similar to Reaction Wheels, Control Moment Gyros use a gimbal to change the rotation of a spinning flywheel. See https://www.youtube.com/watch?v=JTWA6tUREi8 for an excellent visual demonstration of CMG technology.
    • Thrusters: Though far more uncommon on small satellites, thrusters remain a dependable and conceptually straightforward method of attitude determination.

ADCS Specifications

  • ADCS Pointing Accuracy
    • ADCS accuracy varies depending on the type and quality of mechanisms and control systems. The popular CubeSpace hardware used on 2U QB50 satellites has an accuracy of 0.2º to 0.6º (keep in mind, however, that the QB50 missions requirements regarding ADCS precision are fairly lax). The BlueCanyon XB1 high precision ADCS suggests an accuracy of 0.002º.
  • ADCS Maneuvering Rates