The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper investigates the attitude control problem of a three-inline array tethered spacecraft in two-dimensional plane. The three-spacecraft array is decoupled into three individual dynamics. A feedback control law is proposed to stabilize the center spacecraft. For the single-tethered spacecrafts at the tips, a partially simplified nonlinear model is presented. Considering the coupling property...
The inter-beam interference has been shown to be a critical factor in multi-beam satellite communication systems. This paper proposes a novel pilot sequence design criterion aiming at mitigating the inter-beam interferences. The proposed multi-beam optimality criterion is to minimize the worst-case mean square error (MSE) of an least square (LS) based channel estimator. It is shown that we can obtain...
This paper addresses the adaptive coding problem for mobile satellite communication systems with the dual-polarized multi-input multi-output (MIMO) deployment. In general, the satellite communication systems have a long channel delay, and then traditional adaptation schemes suffer from performance degradation. To overcome this drawback, we propose to add statistical channel state information (CSI)...
Residual life is widely recognized as the time period that the system can work normally from the current operating conditions until broken. As an important means of system health evaluation, the residual life prediction has become a research hotspot at home and abroad. The residual life of the satellite attitude control system is affected by a variety of factors. In this paper, the concept of degraded...
In this paper the telemetry data of Satellite TX-I are analyzed in order to have a better understanding of the satellite operating status, and to lay the foundation for fault detection task. Given the high dimensional data, the locally linear embedding (LLE), a kind of manifold learning schemes, is applied to perform dimensionality reduction and feature extraction. Furthermore the data-driven fault...
This paper presents a new filtering based multiple-model control scheme for satellite attitude tracking control in the presence of sign errors in actuator response. As a result of a software or hardware fault, such actuation sign errors which are uncertain in occurring time instants and patterns may lead to the loss of satellites. The control design employs two steps: first, a bank of control laws...
In this paper a finite impulse response (FIR) filter for online adaptive modeling of satellite attitude control systems is proposed, and a recursive least squares (RLS) algorithm is used to adjust the adaptive FIR filter coefficients for minimizing the output error between the monitored system and the FIR filter. The fault information can be obtained through the analysis of the adaptive FIR filter...
Q-law has been studied a lot as an approach to transfer orbits. This paper presents a refined Q-law method integrated with fuzzy logic control for the satellite orbit transfers between arbitrary orbits around a central body. Q-law is adopted to decide thrust angles and determine whether to thrust or to coast. Furthermore, in order to eliminate vibrations, a fuzzy controller is constructed to change...
This paper presents a robust sensor fault diagnosis and compensation scheme for satellite attitude dynamics with perturbations. The satellite attitude dynamics is linearized at the operating points with T-S fuzzy model. By introducing sensor fault as an auxiliary state vector, an augmented descriptor system is constructed. Fault diagnosis and estimation is achieved with a robust fuzzy descriptor observer...
In this paper, we present sliding mode observer (SMO) and sliding mode controller with perturbation estimation (SMCPE) for a micro-satellite attitude system. In view of the microsatellite attitude system where gyro is not available or gyro fails, the quaternion estimating angle rate of satellite is proposed by means of sliding mode observer. The SMO is suitable for microsatellite which is limit by...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.