A model reference adaptive control method is proposed for uncertain nonlinear characteristics of spacecraft attitude control system. This method combines fuzzy control methodology and nonlinear feedback linearization methodology, which made the closed-loop system stable and the state of fuzzy system track the state of reference model according to the parallel distributed compensation theory and...

A method of using magnetic torque rods to do 3axis spacecraft attitude control has been developed. The goal of this system is to achieve a nadir pointing accuracy on the order of 0.1 to 1.0 deg without the need for thrusters or wheels. The open-loop system is under-actuated because magnetic torque rods cannot torque about the local magnetic field direction. This direction moves in space as the ...

In this paper, two different algorithms are presented for the estimation of spacecraft body angular rates in the absence of gyro rate data for a star tracker mission. In first approach, body angular rates are estimated with the spacecraft attitude using a dynamical model of the spacecraft. The second approach makes use of a rapid update rate of star camera to estimate the spacecraft body angula...

A continuous feedback controller with a periodic time varying term for the attitude control of an un-deractuated rigid spacecraft is derived. The attitude is described with the Euler parameter vector. Due to the nondiierentiable nature of exponential stabilizers , sampling of some measurements is used. Global exponential convergence is indicated with analysis and simulations.

A key goal of NASA's New Millennium Program (NMP) is the development of technology for increasing spacecraft on-board autonomy. Achievement of this objective requires the development of a new class of ground-based autonomy testbeds that can enable the low-cost and rapid design, test and integration of the spacecraft autonomy ight software. This paper describes the development of an Autonomy Tes...

In this paper, a real-time predictive filter is derived for spacecraft attitude estimation without the utilization of angular rate measurements from gyros. The formulation described in this paper is shown using only attitude sensors (e.g., three-axis magnetometers, sun sensors, star trackers, etc.). The new real-time nonlinear filter predicts the required torque modeling error input in order to...

An integrated coupled control strategy for a servicing spacecraft autonomously approaching and docking with a freely tumbling target is studied. To implement capturing successfully, the docking port of the servicing spacecraft should be always pointing to the docking port of target during close rendezvous and docking, which involves proximity maneuvering of coupled position and attitude simulta...

In this paper, a new algorithm is developed for attitude estimation using Global Positioning System (GPS) signals. The new algorithm is based on a predictive filtering scheme designed for spacecraft without rate measuring devices. The major advantage of this new algorithm over traditional Kalman filter approaches is that the model error is not assumed to represented by an unbiased Gaussian nois...

This paper addresses three-axis attitude control for a Danish spacecraft, R mer. The algorithm proposed is based on an approximation of the exact feedback linearisation for quaternionic attitude representation. The proposed attitude controller is tested in a simulation study. The environmental disturbances correspond to those expected for the R mer mission. The pros and cons of the algorithm ar...

In this paper, a new algorithm is developed for attitude estimation using Global Positioning System (GPS) signals. The new algorithm is based on a predictive filtering scheme designed for spacecraft without rate measuring devices. The major advantage of this new algorithm over traditional Kalman filter approaches is that the model error is not assumed to represented by an unbiased Gaussian nois...