Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 41 for “"Spacecraft attitude"”.
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Spacecraft Attitude Tracking Control
The problem of reorienting a spacecraft to acquire a moving target is investigated. The spacecraft is modeled as a rigid body with N axisymmetric wheels controlled by axial torques, and the kinematics are represented by Modified Rodriques Parameters. The trajectory, denoted the reference …
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Vehicle model-based filtering for spacecraft attitude determination
… the use of vehicle model-based filtering for spacecraft attitude determination. Whereas traditional navigation filters typically rely only on the kinematic relations between body rate and attitude in their filter designs, the state estimator presented here expands the plant model to include …
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Optimal nonlinear feedback control of spacecraft attitude maneuvers
… are developed for large angle, nonlinear spacecraft attitude maneuvers. Scalar and two-state systems are presented as simple examples to demonstrate the method, and several systems of state variables to parameterize spacecraft motion are considered. Both external and internal control …
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Use of thermal reradiative effects in spacecraft attitude control.
Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Thesis. 1966. M.S.
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Tightly coupled GPS-gyro integration for spacecraft attitude determination
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1997.
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Autonomous Artificial Neural Network Star Tracker for Spacecraft Attitude Determination
… after launch as well as recovery from a loss of attitude knowledge during the mission would occur significantly faster with this prototype system when compared to current commercially available autonomous star trackers."
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Polynomial motion planning in spacecraft attitude and docking to tumbling debris
… the advances in the performance and autonomy of spacecraft operations. However, the computational resources of spacecraft are still limited. In this sense, using polynomials to shape trajectories, and computing accelerations and other parameters via inverse dynamics, is an efficient approach to …
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Adaptive Control Applied to the Cal Poly Spacecraft Attitude Dynamics Simulator
The goal of this thesis is to use the Cal Poly Spacecraft Attitude Dynamics Simulator to provide proof of concept of two adaptive control theories developed by former Cal Poly students: Nonlinear Direct Model Reference Adaptive Control and Adaptive Output Feedback Control. The Spacecraft Attitude …
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A Permanent Magnetic Dipole Reaction Sphere Actuator for Spacecraft Attitude Control
… prototype reaction sphere actuator for spacecraft attitude (orientation) control. Reaction spheres rotate spacecraft either with an equal-and-opposite torque about their rotation axis when accelerated about that axis, similar to reaction wheels, or with a more ecient gyroscopic torque …
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Estimation of spacecraft attitude in the presence of unmodeled disturbance torques
… approach is presented for the estimation of spacecraft attitude from rate gyroscope measurements of angular velocity and indirect inertial orientation measurements obtained from a pair of star sensors. The estimation algorithm is developed in such a way that the measured minus estimated …
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NONLINEAR OBSERVER/CONTROLLER DESIGNS FOR SPACECRAFT ATTITUDE CONTROL SYSTEMS WITH UNCALIBRATED GYROS
Gyroscopes, or gyros, are vital sensors in spacecraft onboard attitude control systems. Gyro measurements are corrupted, though, due to errors in alignment and scale factor, biases, and noise. This work proposes a class of adaptive nonlinear observers for calibration of spacecraft gyros. Observers …
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A novel magnetic field approach to simulate spacecraft attitude determination and control
… which will be capable of achieving 3-axis attitude control via magnetic torque coils and attitude determination via Kalman-filtered magnetometer data with an optional Sun vector measurement. This innovative new attitude determination and control (ADC) method is more sophisticated than those …
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System Integration and Attitude Control of a Low-Cost Spacecraft Attitude Dynamics Simulator
The CalPoly Spacecraft Attitude Dynamics Simulator mimics the rotational dynamics of a spacecraft in orbit and acts as a testbed for spacecraft attitude control system development and demonstration. Prior to this thesis, the simulator platform and several subsystems had been designed and …
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Hamilton-Jacobi-Bellman equation for stochastic optimal control: Applications to spacecraft attitude control
This study aims to address the problem of attitude control of spacecraft in presence of thrust uncertainty, which leads to stochastic accelerations. Spacecraft equipped with electric propulsion and other low thrust mechanisms, often experience random fluctuations in thrust. These stochastic …
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The Distributed Spacecraft Attitude Control System Simulator: From Design Concept to Decentralized Control
A spacecraft formation possesses several benefits over a single-satellite mission. However, launching a fleet of satellites is a high-cost, high-risk venture. One way to mitigate much of this risk is to demonstrate hardware and algorithm performance in groundbased testbeds. It is typically …
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Investigation of Nonlinear Control Strategies Using GPS Simulator And Spacecraft Attitude Control Simulator
In this dissertation, we discuss the Distributed Spacecraft Attitude Control System Simulator (DSACSS) testbed developed at Virginia Polytechnic Institute and State University for the purpose of investigating various control techniques for single and multiple spacecraft. DSACSS is comprised of two …
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An On-orbit Calibration Procedure for Spaceborne Microwave Radiometers Using Special Spacecraft Attitude Maneuvers
… and early results by utilizing Calibration Attitude Maneuvers (CAM), which encompasses Deep Space Calibration (DSC) and a new use of the Second Stokes (SS) analysis that can provide early and much needed insight on the performance of the instrument. This dissertation describes pre-existing …
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Coupled Dynamics in the Cislunar Region and Spacecraft Attitude Prediction in a Higher-Fidelity Model
… may be insufficient for accurately predicting spacecraft motion in environments where orbit-attitude coupling is non-negligible. One of the most famous of such models is the circular restricted three-body problem. This thesis advances the state of the art in astrodynamics by modeling all bodies …
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Estimation of Spacecraft Attitude Motion and Vibrational Modes Using Simultaneous Dual-Latitude Ground-Based Data
… will take the form of speeding up convergence of spacecraft attitude estimates, and of a non-model-based approach to the detection of vibrational modes. Because attitude observability from photometric data is angle-based, dual-site simultaneous photometric observations of a resident space object …
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