Space subsystems design: (navigation, control, structure and…)
M. Navabi; Nazanin Safaei
Volume 13, Issue 4 , December 2020, , Pages 25-35
Abstract
Several novel control techniques have been created as a result of the diversity of researches which are conducted about the problem of satellite attitude control. There are always uncertainties in the problem of satellite attitude control in the space missions. Therefore, Adaptive control is a method ...
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Several novel control techniques have been created as a result of the diversity of researches which are conducted about the problem of satellite attitude control. There are always uncertainties in the problem of satellite attitude control in the space missions. Therefore, Adaptive control is a method which is taken into consideration. High computational volume is one of the problems of adaptive control technique. In this paper, a control technique which is based on optimization concepts is introduced for the problem of satellite angular velocity and attitude control. Also, it's developed based on the three-dimensional special orthogonal group, and it's not faced by a singularity problem. For comparison, the linear quadratic regulator (LQR) control technique is simulated. Finally, the results of the simulations show that the performance of the presented adaptive control technique is optimal, and this method is robust to inertia changes.
Seyed Mohammad Reza Mosavi; Narjes Rahemi; Satar Mirza Kuchaki
Volume 7, Issue 4 , January 2015, , Pages 63-72
Abstract
GPS is a satellite-based navigation system that is able to determine the exact position of objects on the Earth, sky, or space. By increasing the velocity of a moving object, the accuracy of positioning decreases; meanwhile, the calculation of the exact position in the movement by high velocities like ...
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GPS is a satellite-based navigation system that is able to determine the exact position of objects on the Earth, sky, or space. By increasing the velocity of a moving object, the accuracy of positioning decreases; meanwhile, the calculation of the exact position in the movement by high velocities like airplane movement or very high velocities like satellite movement is so important. In this paper, two methods for positioning in very high velocities based on recursive least squares method and its combination with fuzzy logic are presented. Simulations on different data with different velocities show that proposed method can improve the accuracy of positioning more than 50%. In previous methods, the algorithm is quite dependent on the initial point, whereas in proposed method, this dependency is resolved.
