Short- and Long-Term Propagation of Spacecraft Orbits (original) (raw)
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Comprehensive Survey and Assessment of Spacecraft Relative Motion Dynamics Models
Journal of Guidance, Control, and Dynamics, 2017
and his M.S. degree from Stanford University, both in aerospace engineering. He has experience working as an engineering analyst for SpaceX and Space Systems/Loral. His current research focuses on developing advanced algorithms for angles-only relative navigation and rendezvous in distributed space systems as well as formulating improved analytical dynamics models for orbital relative motion. Sebastian Grimberg is a Master's student working in the SLAB at Stanford University. He graduated with a Bachelor of Science in Engineering in mechanical and aerospace engineering and a certificate in engineering physics from Princeton University in 2015. His current research focus is in the field of dynamics models for orbital relative motion, specifically the development of accurate and computationally efficient semi-analytical methods to propagate the relative state in a wide range of orbit scenarios.
A high accuracy modeling scheme for dynamic systems: spacecraft reaction wheel model
Journal of Engineering and Applied Science
Reaction wheels are crucial actuators in spacecraft attitude control subsystem (ACS). The precise modeling of reaction wheels is of fundamental need in spacecraft ACS for design, analysis, simulation, and fault diagnosis applications. The complex nature of the reaction wheel leads to modeling difficulties utilizing the conventional modeling schemes. Additionally, the absence of reaction wheel providers’ parameters is crucial for triggering a new modeling scheme. The Radial Basis Function Neural Network (RBFNN) has an efficient architecture, alluring generalization properties, invulnerability against noise, and amazing training capabilities. This research proposes a promising modeling scheme for the spacecraft reaction wheel utilizing RBFNN and an improved variant of the Quantum Behaved Particle Swarm Optimization (QPSO). The problem of enhancing the network parameters of the RBFNN at the training phase is formed as a nonlinear constrained optimization problem. Thus, it is proposed t...
A semi-analytic approach to spacecraft attitude guidance
Attitude slew motions for spacecraft are usually undertaken using feedback control where only the desired final attitude is stated. In this paper attitude guidance is considered which could be used, in addition to feedback control, to enhance the efficiency of slew motions by pre-planning time-dependent attitude motions. This is achieved using a three-step method in which the angular velocities are expressed as analytic functions in terms of free parameters (on the virtual time domain), and the boundary conditions on the rotation are matched using a shooting method based on a discretized form of Rodrigue's formula. Following this, the virtual time is reparametrized. This is applied to design a rest-to-rest two-impulse slew manoeuver and a slew motion using only two reaction wheels.
Journal Européen des Systèmes Automatisés, 2019
In many space applications, the spacecraft (SC) must have good agility performance, which depends heavily on the capability of attitude control system. This paper aims to maximize the onboard capability of SC attitude control system by optimizing the use of reaction wheels (RWs). The authors firstly investigated the optimal configuration of the rotation axes relative to cluster design frame, and the cluster arrangement relative to the SC body frame. Then, the octahedron pyramid configuration was selected as the RWs configuration. For this configuration, the cluster of two shifted assemblies (four wheels each) has a 20.7 % larger envelope volume, and a 10 % longer inscribed sphere radius than the cluster of coinciding assemblies. Using the optimal agility performance criterion, the cluster of shifted assemblies can maximize the system capability by increasing the SC acceleration by 9.85 % along the worst direction. Subsequently, the controller saturation limits were updated depending based on the number and arrangement of the RWs. In case of one RW off, the SC acceleration in roll or pitch channel could be enhanced by 26.23 %. Overall, our RWs configuration could enhance the SC agility by 38.51 %. The research findings make it possible to optimize the agility of the SC and rationalize the selection and sizing of the RWs.
Modeling, simulation, and control of the spacecraft attitude dynamics
2019
Based on the three-dimensional dynamics of a rigid body and Newton's laws, the simplified dynamics of a spacecraft is studied and described through the systematical representation, mathematical modeling and also by a block diagram representation, to finally simulates the spacecraft dynamics in the Matlab programming environment called Simulink. It is paramount to be able to identify and recognize the attitude (often represented with the Euler angles) and position variables like the degrees of freedom (DOF) of the system and also the linear behavior. All this to conclude up about the non-linear behavior presented by the accelerations, velocities, positions and Euler angles (attitude) when those mentioned are plotted against time. In addition to this, the linearized system is found in order to facilitate the control analysis and stability analysis, at using linear analysis tools of Simulink and concepts like controllability and observability, reaching the point of determining under the previous concepts to proceed with the control design phase. Lastly, an uncertainty and sensitivity analysis is realized, by means the Monte-Carlo and the Linear regression method (in Simulink too), to find the torque like critical model input, since it has the greatest effect on the response variables in the system; and thus finally, to implement the Linear Quadratic Regulator (LQR) controller, at using the lqr Matlab function.
PREFACE This book is the outgrowth of courses taught at Stanford University and at the University of California, Los Angeles, and of the authors' professional activities in the field of spacecraft dynamics. It is intended both for use as a textbook in courses of instruction at the graduate level and as a reference work for engineers engaged in research, design, and development in this field. The choice and arrangement of topics was dictated by the following considerations.
Mission Experience Using New Attitude Tools for Spinning Spacecraft
AIAA/AAS Astrodynamics Specialist Conference and Exhibit, 2008
was significantly enhanced. The AGSS estimator suite includes a spinning spacecraft Kalman filter and three single-axis attitude estimators: the Fuzzycones method, the Magnetometer-Only Single-Axis Estimator/Calibrator (MOSAEC), as well as a standard differentialcorrector batch-method estimator. The calibration suite of tools includes utilities to estimate relative time offsets, magnetometer calibration parameters, and Sun sensor biases.
Analytical Spacecraft Trajectory Optimization
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This monograph examines the problem of trajectory optimization for spacecraft operating within a Newtonian field. Background information of the problem formulation is provided, including the overall investigation objective. A survey of previous works is provided with regards to optimization by means of indirect and direct methods. A formulation of spacecraft equations of motion is provided following definitions of applicable coordinate systems. Specific methods of optimization are conferred in their numerical form, with most attention given to shooting methods for the reason that it was the dominant method used to obtain research results. Direct optimization through collocation is addressed in terms of Runge-Kutta and trapezoidal methods. The document further addresses the conditions of optimality in numerical form, discussing formulation of a performance index for optimality and then classifying applicable conditions of optimality into either first-order or higher-order. Trajectori...
Variable Speed Control Moment Gyroscope Workbench: a new simulation tool for tomorrow's spacecraft
20th DASC. 20th Digital Avionics Systems Conference (Cat. No.01CH37219), 2001
This paper describes the Variable Speed Control Moment Gyroscope (VSCMG) Workbench, a simulation software tool developed at Georgia Tech. This program will provide the Air Force Research Laboratory (AFRL) with a tool for studying spacecraft control system design for vehicles equipped with VSCMG actuators for combined attitude control and energy storage.